IUG-bricks

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Paper Fibre Based Bricks for Low Cost Housing in Developing Countries

Mads Prange Kristiansen

MSc Thesis project in Civil Engineering, 2009

s032486

Foreword The project at hand is conducted as a Master of Science Thesis at the Department of Civil Engineering, Technical University of Denmark (DTU). The conceptual framework for my project arose, as I in my initial project research contacted Engineers Without Borders Denmark (IUG). IUG focuses on humanitarian needs with an overall vision to secure life after survival. The organization has a student branch which seeks to link engineering students and their skills to technical and humanitarian issues worldwide. The project is based on two issues in India, expected poor building materials and waste problems in slums. The project seeks to link these problems to a common solution by using paper fibres as aggregate in a building brick. Geographically, the project is based on the Rasoolpura slum in Hyderabad, state of Andhra Pradesh, India. The project is initiated with an abstract. A brick containing paper fibres is developed based on pre experiments. Selected material properties for the developed brick are measured through experiments. These constitute the basis for evaluating the bricks’ general utility as a building material. A field study was performed in the project, Annex 2. For two weeks I visited India in March, 2009. The field study constitutes the basis for evaluating the bricks utility specifically for the project case, the Rasoolpura slum. During the initial phase of the project the possibility of using enzymes as a binding agent in paper fibre based materials came apparent. A spinoff study was performed on Novozym 51003, Annex 1. This study has no direct connection to the project objective. I owe great gratitude to my supervisor, Associate Professor Kurt Kielsgaard Hansen, who has given great motivation through his own commitment and thorough knowledge in Material Science. Associate Professor Staffan Svansson has shared his extensive knowledge in Wood Science. Further thanks to IUG, who inspired the project initially, and trusted me to perform two seminars on my project, one for members of The Danish Society of Engineering (IDA), and one for students at DTU. Professor Ali Ansari, Professor at Muffakham Jah College of Engineering and Technology (MJCET), chairman on Engineers Without Borders International (EWBINT) and founder of Engineers Without Borders India (EWBI), helped me define the project case and plan my Field Study to Hyderabad. Final year students at MJCET and members of EWBI, Mohammed Abdul Kaleem, Mohammed Arshad Ahmed, Zafar Mahmood and Mohammed Abdul Waheed showed immense hospitality and were indispensable to my visit in Hyderabad. In addition, I thank Papiruld Danmark ApS by Manager Claus Skov, who supplied materials and technical information as well as an excursion at the production facilities.

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The project is performed in the period from the 15th September 2008 till the 5th April, 2009. In the written report, a CD is enclosed which contains a pdf-version of the report and useful Microsoft Excel files containing all data. Danish setup Microsoft Excel was used for computing of testing results. As a consequence, most graphs in the report use “,” as decimal separator instead of “.”. In the text, “.” is used as decimal separator.

Date:

Mads Prange Kristiansen

Front-page picture: Rag picker at the Army Dental College landfill, Hyderabad, India. Photograph is taken by Mads Prange Kristiansen.

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1 Table of contents Foreword ........................................................................................................................ 2 1

Table of contents .................................................................................................... 4

2

Abstract .................................................................................................................. 8

3

Background and purpose...................................................................................... 10

3.1 Background ...................................................................................................... 10 3.1.1 MJCET project summary ....................................................................... 11 3.2 Purpose ............................................................................................................. 13 3.3 Objective for the project................................................................................... 14 3.3.1 Requirements ......................................................................................... 14 3.3.2 Conditions and project case ................................................................... 14 3.3.3 Criterions................................................................................................ 16 3.4 Delimitations .......................................................................................... 16 4 Analytic method ................................................................................................... 17 5

Material selection ................................................................................................. 18

6

5.1 Inorganic binding agent ......................................................................... 18 5.2 Paper fibres ............................................................................................ 18 5.3 Sand and stone aggregates ..................................................................... 19 Preproduction experiments and considerations ................................................... 20 6.1 Preproduction experimental plan ..................................................................... 20 6.2 Gravimetric water content of paper fibres from Papiruld Danmark ApS on delivery............................................................................................................. 21 6.2.1 Scope ...................................................................................................... 21 6.2.2 Experimental setup................................................................................. 21 6.2.3 Experimental procedure ......................................................................... 21 6.2.4 Derivation of gravimetric water content and concise conclusion .......... 22 6.2.5 Discussion and sources of error ............................................................. 22 6.3 Investigation on fibre behaviour at different water levels to clarify useful forming methods .............................................................................................. 23 6.3.1 Scope ...................................................................................................... 23 6.3.2 Experimental setup and apparatus ......................................................... 23 6.3.3 Experimental procedure and apparatus .................................................. 23 6.3.4 Physical observations at the four phases ................................................ 24 6.3.5 Observations on volume reduction when forming paper pulp in cylinders ................................................................................................................ 26 6.3.6 Discussion .............................................................................................. 27 6.3.7 Sources of error and concise conclusion ................................................ 27 6.4 Determination of fibre and lumen saturated outer surface dry state and density of paper fibres .................................................................................................. 29 6.4.1 Scope ...................................................................................................... 29 6.4.2 Determining fibre and lumen saturated surface dry- state for paper fibres ................................................................................................................ 29 6.4.3 Water absorption in cellulose fibres dependency on time ..................... 30 Page 4 of 106

6.4.4 6.4.5

Experimental setup and procedure ......................................................... 30 Derivation of fibre and lumen saturated outer surface dry density, Ď f.l.s.s.d. ................................................................................................................ 31 6.4.6 Discussion .............................................................................................. 31 6.4.7 Sources of error ...................................................................................... 32 6.4.8 Concise conclusion ................................................................................ 32 6.5 Determination of sieving curves for 0-4 mm sand ........................................... 33 6.5.1 Scope ...................................................................................................... 33 6.5.2 Experimental setup, apparatus and procedure ....................................... 33 6.5.3 Derivation of sieving curves for 0-4 mm lake sand and conclusion ...... 33 6.6 Consideration on geometry related conditions for setting of paper fibre based cement mortar................................................................................................... 35 6.6.1 Scope ...................................................................................................... 35 6.6.2 Identification of special considerations - comparison between traditional and paper fibre based mortars .............................................................................. 35 6.6.3 Specific surface in traditional mortar or concrete and paper fibre based mortars ................................................................................................................ 37 6.6.4 Discussion .............................................................................................. 39 6.6.5 Sources of error ...................................................................................... 41 6.6.6 Concise conclusion ................................................................................ 42 6.7 Determination of slump dependency on free water content in paper fibre based cement mortar................................................................................................... 43 6.7.1 Scope ...................................................................................................... 43 6.7.2 Lyses’ law and general considerations for free water in paper fibre based cement mortar ...................................................................................................... 43 6.7.3 Experimental setup and apparatus ......................................................... 43 6.7.4 Experimental procedure ......................................................................... 44 6.7.5 Water/cement-relation change ............................................................... 45 6.7.6 Derivation of slump dependency on the water content .......................... 45 6.7.7 Discussion .............................................................................................. 46 6.7.8 Sources of error ...................................................................................... 47 6.7.9 Concise conclusion ................................................................................ 47 6.8 Concise conclusion of chapter 6 ...................................................................... 48 7 Derivation of paper fibre based brick production formula and method ............... 49 7.1 Production formula........................................................................................... 49 7.1.1 Production method ................................................................................. 49 8 Determination of material properties for CEMCEL Bricks ................................. 53 8.1 Material properties and parameters experimental plan .......................... 53 8.2 Porosity and density ......................................................................................... 54 8.2.1 Scope ...................................................................................................... 54 8.2.2 Experimental setup and apparatus ......................................................... 54 8.2.3 Experimental procedure ......................................................................... 55 8.2.4 Correlation between porosity and other properties ................................ 55 8.2.5 Determination of porosity and density ................................................... 56 8.2.6 Calculation ............................................................................................. 56 8.2.7 Discussion .............................................................................................. 57 8.2.8 Sources of error ...................................................................................... 62 8.2.9 Concise conclusion ................................................................................ 62 8.3 Capillary suction .............................................................................................. 63 Page 5 of 106

8.3.1 Scope ...................................................................................................... 63 8.3.2 Experimental setup and apparatus ......................................................... 63 8.3.3 Experimental procedure ......................................................................... 64 8.3.4 Capillary suction capability ................................................................... 64 8.3.5 Discussion .............................................................................................. 66 8.3.6 Sources of error ...................................................................................... 67 8.3.7 Concise conclusion ................................................................................ 68 8.4 Thermal conductivity ....................................................................................... 69 8.4.1 Scope ...................................................................................................... 69 8.4.2 Experimental setup and apparatus ......................................................... 69 8.4.3 Experimental procedure ......................................................................... 70 8.4.4 Determination ........................................................................................ 71 8.4.5 Calculation ............................................................................................. 71 8.4.6 Discussion .............................................................................................. 71 8.4.7 Sources of error ...................................................................................... 74 8.4.8 Concise conclusion ................................................................................ 74 8.5 Moisture related deformation and hysteresis ................................................... 75 8.5.1 Purpose ................................................................................................... 75 8.5.2 Experimental setup and apparatus ......................................................... 75 8.5.3 Experimental procedure ......................................................................... 76 8.5.4 Determination ........................................................................................ 77 8.5.5 Discussion .............................................................................................. 78 8.5.6 Sources of error ...................................................................................... 80 8.5.7 Concise conclusion ................................................................................ 80 8.6 Compression strength and stress/strain-relation curve ..................................... 81 8.6.1 Scope ...................................................................................................... 81 8.6.2 Experimental setup and apparatus ......................................................... 81 8.6.3 Experimental procedure ......................................................................... 82 8.6.4 Primary testing - Determination of compression strength and stress/strain relation ............................................................................................. 83 8.6.5 Secondary testing - Comparison of compression strength and stress/strain relation for chemically pulped paper fibres ..................................... 87 8.6.6 Tertiary testing - Sensitivity analysis on the compression strengths dependency on the w/c- ratio ............................................................................... 88 8.6.7 Discussion .............................................................................................. 89 8.6.8 Sources of error ...................................................................................... 89 8.6.9 Concise conclusion ................................................................................ 89 8.7 Investigation of biological deterioration .......................................................... 90 8.7.1 Scope ...................................................................................................... 90 8.7.2 Experimental setup and procedure ......................................................... 90 8.7.3 Determination and discussion ................................................................ 90 8.7.4 Concise conclusion ................................................................................ 91 8.8 Analysis of microstructure and elemental composition ................................... 92 8.8.1 Scope ...................................................................................................... 92 8.8.2 Experimental setup and procedure ......................................................... 92 8.8.3 Microscopic analysis on geometry the paper fibres delivered from Papiruld Danmark ApS ........................................................................................ 92 8.8.4 Scanning Electron Microscope analysis on CEMCEL Bricks ............... 93 8.8.5 Energy Dispersive X-ray Spectroscopy analysis ................................... 97 8.8.6 Concise conclusion ................................................................................ 99 Page 6 of 106

9

8.9 Concise conclusion of chapter 8 .................................................................... 100 Conclusion ......................................................................................................... 102

10 The project in perspective .................................................................................. 103 References .................................................................................................................. 104 Appendix overview .................................................................................................... 106

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2 Abstract The present project concerns paper fibre based bricks for low cost housing in developing countries. The project case is the Rasoolpura slum in Hyderabad, state of Andhra Pradesh, India. The project addresses two problems in Rasoolpura, expected poor building materials and extensive waste problems. Using waste paper fibres as aggregate in cement based building bricks, these two problems are sought to partly solve each other through development and production of a paper cellulose fibre based brick. The project starts with an exposition of the project background, purpose, objective and delimitations, followed by a method section wherein the analytic methods used in the project are described. In chapter 5, clarification is given to the materials used in the development process of a paper fibre based brick. These are Aalborg Portland Basis (ABC) Cement, paper fibres from Papiruld Danmark ApS, 0-4 to 4 mm sand and 4-8 mm stones. A series of preproduction experiments are performed in the development process to define the boundaries for composition and production of a paper fibre based brick, chapter 6. Several experiments are performed in the following categories: o Paper fibres behaviour related experiments o Sand behaviour related experiments o Mortar behavior related experiments It is evaluated that the composition boundaries limit the paper fibre content to 3.7 vol-% in dry state, the remaining aggregates 50 vol-% 0-4 mm sand and 31 vol-% of 4-8 mm stones. The cement content should be 290 kg/m3, with a w/c-ratio of 1.0. The bricks must be shaped using compression. The bricks are shaped in mould to dimensions 220 mm * 100 mm * 70 mm, equal to the Indian standard. The chapter ends with a concise conclusion, where experimental results are set up schematically. A conclusive formula and production details regarding mixing, forming and curing is given in chapter 7. Based on the limit of allowed cellulose paper fibres found in chapter 6, the bricks are named CEMCEL Bricks (CEMent and CELlulose paper fibre Bricks) instead of paper based bricks. Chosen material properties are experimentally derived in chapter 8. The results are compared to conventional building materials to give the reader a reference. The following material properties are derived: o Porosity and density o Capillary suction o Thermal conductivity o Moisture related deformation and hysteresis o Compression strength and stress/strain-relation curve o Investigation of biological deterioration o Analysis of microstructure and elemental composition The CEMCEL Brick is a porous material with a porosity of 36 % and a dry density of 1664 kg/m3. This makes it lightweight compared to reference materials. Page 8 of 106

From the capillary suction experiment, the water absorption coefficient, k, is found to 0.090 kg/(m2*s1/2). The resistance coefficient, m, is found to 7.64 * 106 s/m2. The CEMCEL Bricks generally absorbs water slower than conventional concrete and burned bricks. When dried at 50 °C until a moisture content of 1.8 weight-%, the thermal conductivity is found to 0.43 W/(m*K). This is superior to most reference materials. The thermal conductivity is dependent on the water content and increases with an increase in the water content. Moisture related deformation was quantified. A freshly cured CEMCEL Brick with a water content of 10-19 weight-% will shrink 0.075 % when dried to 50 % RH at 32 ĚŠC. This is more than most reference materials. To avoid hazardous coherent tension stresses, the CEMCEL Bricks should be sundried after curing but before building. When freshly cured after 45 days CEMCEL Bricks have a compression strength of 3.7 MPa. This is poor compared to most cement based materials, but superior to medium density cellular concrete and sufficient for single storey housing like the Rasoolpura dwellings. The compression strength is postulated to increase after building, as the CEMCEL Bricks dries. The organic cellulose paper fibres are subject to potential biological deterioration. The experiment performed did not give any general conclusions on biological deterioration for the CEMCEL Brick. The elemental composition between carbon, oxygen, aluminium, silicon and calcium is: carbon 18 % to 22 %, oxygen 44 % to 45 %, aluminium 0.15 % to 0.30 %, silicon 2 % to 4 % and calcium 30 % to 35 %. This is in coherence with the elemental composition of paper fibres, cement paste and aggregates. The main conclusion of the project is that the CEMCEL Bricks are considered to have general practical utility as building bricks. However, the feasibility of the bricks as a building material in relation to the slums in Rasoolpura is evaluated low.

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3 Background and purpose 3.1 Background According to United Nations Population Fund, UNFPA’s, annual State of World Population Report 2007 [1], 24.71 million people were homeless home at the end of 2006. 99 % of these people lived in developing countries like India. In the developing process, urbanisation changes the inhabitants life from rural towards urban. This tendency has and will change the percentage of people in developing regions living in cities from 18 % in 1950 to an expected 56 % in 2030. The part of the urban population living in slums is increasing due to general urban job shortage. The number of Indian slum dwellers is estimated at 40.3 millions in the 2001 census. This was about 14.2 % of the total urban population of 284 millions in India. Today, year 2008, India’s urban population is 329.4 millions and increasing 2.3 % per year. The percentage of slum dwellers has increased accordingly. Presently exactly half of the world’s total population of 6.61 billion people live in urban areas. In developing regions like India this generates massive and growing wastage problems. In lack of an effective renovation system, potentially recycled waste end up in landfills. Landfills, in its most primitive version, are enormous excavations where unsorted waste is dumped, leaving it to slowly decompose over many decades. Obvious hazards are contamination of groundwater and disease carrying insects, birds and small mammals scavenging the landfills, spreading diseases to humans. A substantial part of the waste is cellulose fibre based materials, often paper. During my initial research of potential subjects for my MSc Thesis, I contacted Engineers Without Borders, Denmark (EWBDK). EWBDK is a technical Non Governmental Organisation established in 2001, focusing on humanitarian need with the vision; “Based on engineering and technical expertise, Engineers Without Borders will provide life sustaining assistance to people in disaster-stricken areas and provide technical assistance for humanitarian projects, which can alleviate distress”[2]. The organization has a student wing which aims to involve future engineers in their work. After having studied their project list and discussing options with representatives János Hethey and Johanne Wibroe, I was excited about a project involving the above mentioned issues in housing shortage and waste disposal problems in the city of Hyderabad, India. Two engineering students from Muffakham Jah College of Engineering and Technology (MJCET) recently participated in the Engineers Without Borders, India (EWBIN) Green Award Student Competition. The competition was supervised by Professor at MJCET, Ali Ansari, who is founder of EWBIN and chairman of Engineers Without Borders, International (EWBINT). Their project concerned the use of alternative paper-based building bricks for cost-effective and environmentally sustainable buildings in the Rasoolpura slum in Hyderabad. The vision of the project was that the stones in the near future can be used effectively for the construction of affordable housing. In the following a summary of the MJCET project is presented to give the reader of the project at hand an impression of the inspiration which has formed the foundation for my subject selection.

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3.1.1 MJCET project summary The two students from MJCET, Rafay Salman and Nitya Malladi started the project with two main objectives; an inexpensive and sustainable building brick, helping the waste problems and housing shortage problems in India. The following is referenced from their project results. The components of the brick are waste paper, cement and sand, fine soil or ash. Cement reduces drying time and initial shrinking. Sand or ash improves the fire resistance. Finally lime or commercial products for water-proofing and termites proofing is admixed. In the processing, the paper material is mixed with water to achieve pulp consistency. The water in the paper pulp is the only water contribution to the final mixture. Paper pulp, cement, sand or ash and additives are mixed to achieve the final mixture ready for forming and drying. The paste is poured into a brick form measuring the conventional Indian brick dimensions 22 cm Ă— 10 cm Ă— 7 cm. Finally the bricks are left to dry outside for 3 days in Indian climate to obtain dry composition. No pressure is applied during the process. The wet weight composition is listed in Table 1. Composite

Waste paper pulp Cement Sand, soil or ash

Wet composition, weight-%

52 22 26 <1

Additives Table 1. Wet weight composition of MJCET paper fibre based brick [3].

In the curing process, the water in the paper pulp reacts with the cement or vaporises to the surroundings. Consequently, the relative percentage of cement and sand, soil or ash increases and the dry waste paper weight percentage is revealed. The weight composition of the cured, dry bricks, are shown in Table 2. Composite

Dry waste paper Cement Sand, soil or ash

Dry composition, weight-%

25 34 41 <1

Additives Table 2. Dry weight composition of MJCET paper fibre based bricks after curing [3]

Based on Table 1 and Table 2, the water content of the wet composition can be extracted to 36 % of the final mixture before curing, or 69 % of the waste paper pulp. Thus, the weight percentage of waste paper in the wet composition is 16 %. A summary of the material properties from the MJCET project [3] is given in Table 3. The table shows the values found and according units used in the MJCET project. These units are converted into standard SI units or common used units and displayed in Table 3 along with the appurtenant values. When no results exist, fields are left blank.

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Name Dry density Porosity Thermal conductivity Specific heat capacity Water vapour permeability Young's modulus Compression strength, cracking Compression strength, crushing Coefficient of linear expansion Moisture related strain, wet to 50 % RH

Symbol ρd p λ cp δ E fc f cr α -

Given units 3 g/cm 0.539 80 % 2 2-3 Btu/ft °F*h kg/cm2 9.52 2 kg/cm 67.46 -

-

converted SI units 3 kg/m 539 80 % 0.3 - 0.4 W/(m*K) J/(kg*K) - kg/(Pa*m*s) GPa 0.9 MPa 6.6 MPa -1 °C 0 /00 -

Table 3. MJCET paper fibre based brick measured material properties [3]

To create a reference for comparison, the found SI values along with values for materials; cellular concrete medium density and hard burned bricks, is listed in Table 4.

Name Dry density

Symbol ρd

Porosity Thermal conductivity Specific heat capacity Water vapour permeability Young's modulus Compression strength, cracking

p λ cp

Compression strength, crushing coefficient of linear expansion Moisture related strain, wet to 50 % RH

δ E fc f cr α -

Cellular Paper concrete, based medium Bricks, hard burned Unit brick density 539 500 1800 80 80 0.3 - 0.4 0.12 960 -12 - 70 * 10 15 0.9 6.6 -

2.5 -6 7.5*10 0.65

3

kg/m

30 % 0.35-0.58 W/(m*K) 960 J/(kg*K) -12 30*10 kg/(Pa*m*s) 15 GPa MPa 65 -6 5.5*10 0.0075

MPa -1 °C 0 /00

Table 4. MJCET paper fibre based brick measured material properties. Reference values for materials; cellular concrete medium density and hard burned bricks [4]. Values extracted from [4] are referenced as mean values when listed in [4] as intervals.

In addition to the properties listed in Table 3, the MJCET project indicates numerous advantages of both environmental and social nature. Waste paper can be obtained in excessive amounts from landfills or separation of waste prior to disposal in the landfills free of charge. In consequence, the scale of landfills and associated pollution is decreased. The sand, soil or ash component is also obtained locally from numerous disposable sources at an insignificant cost. Cement is commonly available in India, but has a high economical price compared to the other components. The material cost per brick is estimated to almost half that of traditional earthen bricks, namely 1.26 Indian rupees, the equivalent of 2.00 eurocents, based on local cement price of 4.50 Indian rupees per kilogram. Based on these prerequisites, the bricks can be produced in any scale of numbers by any individual or local community with a very limited amount of necessary tools and financial commitment. They have no known harmful by-products or effects. The above circumstances bring about a potential or partial solution for the overall problems described in section 3.1. However, it was discovered by the MJCET research that the bricks expands laterally when applied with compression forces. Also, it cracks if wetted after production. Hence, the idea of paper fibre based bricks needs additional research. Page 12 of 106

3.2 Purpose The project aims to conclusively determine material compositions and production techniques with practical utility. On this basis, a paper fibre based brick is sought developed. Further, selected appurtenant material properties will be determined and analysed through experiments. On this basis, clarification is sought on whether and to what extent; paper fibre based bricks with technical utility can be deployed in low-cost housing in the Rasoolpura slum in Hyderabad, state of Andhra Pradesh, India.

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3.3 Objective for the project The objective of the project is divided into requirements, conditions and criterions.

3.3.1 Requirements A series of preproduction experiments must be performed to determine the production “boundaries” for production of consistent paper fibre based bricks. A mortar formula and production method must be derived on this basis. A range of testing specimens must be produced based on the derived mortar formula and production method. These specimens must be tested to reveal chosen material properties. Ultimately, results are reflected on the project’s overall purpose to determine the bricks’ utility as an alternative to existing building materials in the Rasoolpura slum in Hyderabad, India. The material properties tested for the paper fibre based bricks are as follows:  Porosity and density  Capillary suction  Thermal conductivity  Moisture related deformation and hysteresis  Compression strength and stress/strain-relation curve  Investigation of biological deterioration  Analysis of microstructure and elemental composition

3.3.2 Conditions and project case To the extent possible, CEN standards are used for the experiments. In cases where such do not exist, testing guides made by Department of Civil Engineering at Technical University of Denmark is used. All tests are performed on apparatus available at the Department of Civil Engineering at the Technical University of Denmark. The aim is to specify conditions that are pertinent to the project, so as to secure relevance. Respective to the project background in section 3.1, the Rasoolpura slum in Hyderabad is the overall frame. In the preliminary phase of the project, a meeting was established with Prof. Ali Ansari. The meeting agenda and summary is given in appendix 1. Based on the meeting, the conditions for the project are outlined as a project case description in the following. The case contains terms of local, materials, constructional and climatic nature. These terms will be the reference when the project results are to be evaluated and concluded upon.

3.3.2.1 Local terms Respect to the local terms is of absolute importance. To insure relevance, the local context must be included when solutions are evaluated. Residents of the slums in Hyderabad are typically engaged as follows: Most adult men have jobs in the city. Types of work vary, as do incomes. The income range might be Rupees 1500 per month to Rupees 4000 per month per family, the equivalent of 25 € to 65 €. Thus they are able to make a living, enough to buy food and clothing and Page 14 of 106

other bare essentials. As for women, about 30 % are gainfully employed outside the home, or self employed, and earn something to supplement their husbands’ income. Others stay home and do housework - cooking, keeping house, and taking care of small children. Consequently, the slum dwellers in the Rasoolpura slum have very poor economic conditions. Relative to their economy, they have much greater working potential. Hence, solutions should be sought work heavy, conversely economically light. Many families have ownership of their homes, but others live in rented houses, paying anywhere between Rs. 500 to Rs. 2000 per month for a 2 room house with kitchen and toilet. Some of the houses have toilets inside the house. Otherwise people ease themselves outside, causing extreme filth. Women, who do not have toilets in their homes, are much worse off, since the few community toilets are unusable due to lack of water and hygiene. Lack of safe and affordable cooking fuel is a common problem. Maybe 20 % to 30 % families can purchase LPG gas cylinders. Many use kerosene stoves. Those living in extreme poverty (perhaps 5% of the slum population) look for sticks, dead wood, twigs etc. or use dried cow dung cakes as cooking fuel. Probably 60 % to 70 % of the children go to school. Some are sent to work, though child labour is illegal. The level of illiterate amongst Indian people in general is 27 % for males and 52 %for women. In the Rasoolpura slum it might be as high as 60 % for men, 40 % for women, indicating the importance of low-tech and low-info solutions. This also emphasizes the need for “elastic solutions”, elasticity indicating that production methods and compositions should have relatively low success sensitivity.

3.3.2.2 Materials terms At the landfills recycle paper is plentiful and can easily be collected. The paper is similar to recycled paper in Denmark such as that used in newspapers. At the riverbeds in and around Hyderabad, water, sand and small stones can be collected free of cost. These have similar properties to those in the foundry at the Department of Civil Engineering, Technical University of Denmark. Cement can be purchased locally. To secure the economical incitement, the amount of cement in the mortar cannot exceed 290 kg/m3. The cement is similar to Aalborg Portland Basis cement.

3.3.2.3 Constructional terms Almost all houses in Rasoolpura slum are constructed from ordinary bricks and cement mortar, most of them having tin or aluminium roofs, a few with reinforced cement roofs. Very few are bricks plastered with mud. The houses are typically very small – one or two small rooms – sometimes there is no separate kitchen. A household of two adults and 3 – 4 children is likely to have two rooms on a gross area of 20 m2 containing kitchen, eating and sleeping facilities. There are no windows and one hinged door. Brickwork is single with no cavity. Bricklayers use traditional cement based mortar.

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3.3.2.4 Geographic and climatic terms The city of Hyderabad in India is located on the Deccan Plateau in the southern part of India. Hyderabad is the capital of Andhra Pradesh, which is the largest state in the south of India. The geographical location of Hyderabad is 17.20 N Latitude and 78.30 E Longitude. It is situated at an altitude of 536 meters above sea level. Located on the East coast of India, the state of Andhra Pradesh stretches along the coast of Bay of Bengal. In the summer, temperatures rise to aggressive 45 째C, and never fall under 13 째C. The humidity also varies largely during the seasons. To make climatic reference conditions, the climate used in the project case is constant at 32 째C and 85 % RH.

3.3.3 Criterions The objective is considered met, if the composition and production boundaries, within which paper fibre based bricks can be produced, are clarified. The material properties, cf. the above listed tests, should be determined and assessed in order to establish the technical utility of the paper fibre based bricks. Based on these findings, the feasibility of the bricks in relation to the slums in Rasoolpura must be evaluated.

3.4 Delimitations The core scope of the project is the paper fibre based bricks. Hence, other constructional aspects of low cost housing such as foundation issues etc. are not considered. The project addresses the potential providing of a sustainable solution to provide an affordable and easy accessible building brick. Through the project, a series of presumptions are made. Though effort is put into verifying these, they are subject to potential incorrectness. The project is performed within these and does therefore not involve circumstances that are not comprised by the presumptions.

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4 Analytic method In this section, the analytic method used in the project is explained. Initially, an explanatory and descriptive clarify the context of the project. Then follow an analysis phase of the used materials, in order to produce the paper fibre based bricks in the production phase. The bricks are evaluated and analysed through its material properties. Finally, these evaluations and analysis are combined to make a synthesis and evaluation phase, concluding on the paper fibre based bricks’ utility. 

Explanation/descriptive phase

Case definition

Analysis phase

Preproduction experiments

Production phase

Evaluation and analysis phase

Material properties

Synthesis and evaluation phase

Conclusion

Paper fibre based brick production

Figure 1. Overall analytic method diagram.

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5 Material selection The purpose of the chapter is to clarify the materials used in the following paper based brick development.

5.1 Inorganic binding agent In modern constructions, inorganic binding agents are being used widely. Cement, lime and gypsum are the three main categories. They mainly consist of calcium, silicon and aluminium oxides. These oxides are crucial for the chemical reactions which govern the inorganic binding agents use. The raw materials are naturally occurring LIME stones, clay, sand and gypsum in different compositions, depending on the specific binding agent. Inorganic binding agents are subdivided into two categories depending on the setting process; hydraulic and non-hydraulic. Hydraulic binding agents can set submerged in water without the presence of air. Gypsum and cement can set under water, but gypsum is not waterproof after setting, and will deteriorate over time if left submerged after setting. Whether an inorganic binding agent is hydraulic or not, depends on its content of Silicon dioxide, SiO2. Figure 2 shows that the hydraulic effect occurs only at SiO2 levels higher than 6 %. The hardening process of non-hydraulic binding agents in air is depending on carbon dioxide. This limits the utility.

Figure 2. Chemical composition pyramid for the inorganic binding agents. Dashed line shows the limit for hydraulic binding agents. Above the line is hydraulic. Figure is in Danish. [15].

Based on the above, Aalborg Portland Basis (ABC) Cement is used in the project.

5.2 Paper fibres Recycled paper from newspaper will be used in the project. The paper is sought representative to that in the landfills. The paper fibres used is delivered from Papiruld Danmark ApS. The company and production facility were visited to secure that the Page 18 of 106

product was useful. The visit it referenced in appendix 2. The product contains fireretardant salts. On request, Papiruld Danmark ApS produced paper fibres without salts especially for this project.

5.3 Sand and stone aggregates The sand is considered to have similar chemical and physical properties as that in Indian riverbeds. All sand and stone aggregates used in the project are from the foundry at the Department of Civil Engineering, Technical University of Denmark. Sand of 0 mm to 4 mm diameter is used. Stones of 4 mm to 8 mm diameter are used. Sieving curves for both materials are given in appendix 3.

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6 Preproduction experiments and considerations In this section, preproduction experiments are performed to define the boundaries for production of the paper fibre based brick.

6.1 Preproduction experimental plan The plan to define the boundaries for production of a paper fibre based brick is diagrammed in Figure 3, which includes a series of paper fibres, sand and mortar related experiments.

Paper fibres behaviour related experiments

Determination of gravimetric water content of paper fibres from Papiruld ApS on delivery Investigation on fibre behavior at different water levels Determination of fibre and lumen saturated outer surface dry density of paper fibres

Sand behaviour related experiments

Determination of sieving curves for 0-4 mm sand and 48 mm stones

Mortar behavior related experiments

Consideration on geometry related conditions for setting of paper fibre based cement mortar

Derivation of mortar formula and production method

Determination of slump dependency on free water content in paper fibre based cement mortars

Figure 3. Paper fibre based brick development plan.

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6.2 Gravimetric water content of paper fibres from Papiruld Danmark ApS on delivery 6.2.1 Scope The scope of this testing is to determine the gravimetric water content of paper fibres from Papiruld Danmark ApS on delivery from the factory.

6.2.2 Experimental setup The paper fibres are delivered in plastic bags as shown in Figure 4. The bags are heat sealed in the production so that no moisture can escape or enter. Therefore, the water content at testing can be assumed equal to that on delivery.

Figure 4. Paper fibres packed in plastic bags, as delivered from Papiruld Danmark ApS. Note the writing�٪salt�, indicating that these bags of paper fibres are specially produced without any additives as requested for this project. The bags’ dimension is 370 mm * 400 mm * 900 mm.

Right after opening of the bags, the paper fibres are prepared as follows: 4 petri dishes of 2 litres each are filled with paper fibres. The fibres are slightly compressed to allow more fibres into the petri dishes. This improves the accuracy of the test. The fibres for the 4 testing samples are mixed before put into the petri dishes. This is done to assure that any local moisture content differences within the bag are accounted for, making the samples representative for the delivered paper fibres.

6.2.3 Experimental procedure The gravimetric water content is determined by weighing the samples together with the petri dishes and subtracting the weight of the petri dishes, giving the weight of the samples alone, m1. The samples are dried in an oven at 105 °C for two days and then weighed after they have been cooled down to below 35 °C in a desiccator, m0. The cooling is required because the mass of the air in the pores drops with temperature increase, causing a potential source of error. The gravimetric water content, u, is derived from Equation 1. đ?‘˘=

đ?‘š 1 −đ?‘š 0 đ?‘š0

Equation 1

The gravimetric water content is determined for all four test specimens and the average is calculated.

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6.2.4 Derivation of conclusion

gravimetric

water

content

and

concise

The gravimetric water contents are given in appendix 4. The average is calculated to 8.7 weight-%.

6.2.5 Discussion and sources of error The samples used to derive the gravimetric water content are taken from one of a three delivered bags. The content of all three is from the same production and was bagged when the facility was visited. Nevertheless, difference in gravimetric water content between the three bags is possible but expected to be small. Within the individual bags, gravimetric water content variations are unlikely to occur as the fibres are mixed in the production. As the bags are sealed, differences due to vaporising from the fibres closest to the bag surface are unlikely.

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6.3 Investigation on fibre behaviour at different water levels to clarify useful forming methods 6.3.1 Scope The scope of the experiment is to determine and evaluate how the paper fibres behave in the mortar at different water levels at and above the fibre and lumen saturated outer surface dry state (f.l.s.s.d.-state), explained in section 6.4. Hereby, practical verification of the occurrence of free water at water levels above the f.l.s.s.d.-state is sought. Moisture related volume technical properties are to be clarified. The experiment aims to provide clarification on how paper fibre based bricks can and should be formed prior to hardening.

6.3.2 Experimental setup and apparatus The experimental setup consists of two 20 litre buckets, 2000 g of water and a total of 884 g of paper fibres with delivery water content, Figure 5, referring to a final water content of 2000 g / 884 g = 226 weight-%. From section, 6.4.8, this refers to the f.l.s.s.d.-state, adjusted for delivery moisture found in section 6.2.4.

Figure 5. Experimental setup, 2.0 litre of water and 0.884 kg of paper fibres.

6.3.3 Experimental procedure and apparatus The 2000 g of water is put in a bucket, and paper fibres are added in phases as shown in Table 5. Phase 1 2 3 4 Water content [g] 2000 2000 2000 2000 Paper fibre content [g] 525 700 800 884 Accumulated pulp content [g] 2525 2700 2800 2884 Water content [weight-%] 381 286 250 226 Table 5. The four water contents evaluated. Number four is that of f.l.s.s.d.-state.

During each phase, visual and physical observations during and after the mixing are made and noted. At phase 4, the overall volume difference between the water and paper fibres before and after mixture is evaluated. Three 100 mm * 200 mm (diameter *height) cylinders are filled and formed using the following methods: 1. First cylinder was stamped 25 times against a solid surface. 2. Second cylinder was vibrated on a concrete vibration table, till no further compacting could be observed. 3. Third cylinder was compressed with hand force. After each forming method, the volume change is observed and noted. Page 23 of 106

Ultimately, the f.l.s.s.d.-state paper fibres are formed in 100 mm * 200 mm (diameter * height) cylinders, using stamping, vibration and compression to observe volume technical properties, Figure 6.

Figure 6. Left: Forming by stamping on hard surface. Middle: Forming by vibration on vibration table. Right: Forming by compression with hand force.

6.3.4 Physical observations at the four phases

6.3.4.1 Phase 1 At this phase, the water content is 381 weight-%. The pulp consistency was chunky, and an easy hand squeeze resulted in large spillage of free water and a compact paper fibre ball when released. When additional paper fibres were added, these would quickly obtain even water distribution, indicated by colour match, meaning that plenty of free water is available.

Figure 7. Pulp consistency observations, phase 1. Left: Uncompressed. Right: compressed till water spillage. Handwriting; total mass of pulp, 2525 g.

6.3.4.2 Phase 2 The water content is 286 weight-%. The pulp consistency was very small chunks, and a firm hand squeeze released a moderate amount of free water. The compressed ball would easily break after release. In this phase, additional paper fibres took 5 minutes of mixing to obtain even water distribution.

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Figure 8. Pulp consistency observations, phase 2. Left: Uncompressed. Right: compressed till water spillage. Handwriting; total mass of pulp, 2700 g.

6.3.4.3 Phase 3 At this phase, the water content is 250 weight-%. The pulp consistency has no chunks, and only at a very hard squeeze, a minimal of free water is released. The compressed ball falls completely apart after release and even water distribution taken more than 10 minutes, indicating that the amount of free water is very low.

Figure 9. Pulp consistency observations, phase 3. Left: Uncompressed. Right: compressed till water spillage. Handwriting; total mass of pulp, 2800 g.

An additional test was performed to see how the pulp would react to additional water. A handful of phase 3 pulp was placed on a non absorbing surface in a cone shape. 10 ml of water was slowly poured over and left for one minute. After one minute, the pulp was lifted carefully away, showing that most of the water had run straight through the pulp, indicating the fibres seemingly were close to the f.l.s.s.d.-state.

Figure 10. Testing for water penetration in pulp. Left: Cone of pulp before water is poured. Middle: Pouring of 10 ml water. Right: Observation of water penetration through the pulp, as water drops had formed on the surface of the disc when the pulp was removed.

6.3.4.4 Phase 4 The water content is 226 weight-%, referring to the f.l.s.s.d.-state. Release of free water is practically impossible by hand squeeze, and when released, the fibres partly Page 25 of 106

spring back to their pre compression volume, indicating a spring effect, which will be discussed in section 6.3.6.

Figure 11. Pulp consistency observations, phase 4. Uncompressed. Handwriting; total mass of pulp, 2884 g.

When comparing the volume of the 2 litre water and 884 grams of paper fibre before and after mixing, it is evident that the water content has a high significance for the volume of the paper fibres. After mixing, the pulp constitutes 39 % of the volume before mixing, explained in Figure 12.

Figure 12. Volume ration of 2 litre water and 884 grams of paper fibres before and after mixing. Left: before. Right: After.

This observation indicates that the fibres are packed more closely or perhaps more practical with a higher water content. This observation is expected to be a consequence of the paper fibres increase in density when wetted, causing a higher load in the pulp, making it self-compacting.

6.3.5 Observations on volume reduction when forming paper pulp in cylinders Three cylinders were filled and formed as described in section 6.3.3. The three methods represent common general methods of forming, depending on the materials, product etc. Stamping is used in handcrafted tiles, vibration in conventional concrete work and compression typically in plate materials. Therefore the observations gives a large scale perspective on the general circumstances under which paper fibre based bricks can be formed. The observations are shown in Figure 13. For both the vibration and the stamping method, it seemed that the fibres sprung back to its previous volume.

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Figure 13. Volume change of paper pulp formed in cylinders. Left: using stamping. Middle: using vibration. Right: using hand compression. Percentages indicate how much the pulp was compressed.

6.3.6 Discussion The consistency and physical behaviour of the pulp in phase 4 indicates that the f.l.s.s.d.-state definition is solid, and that the pulp can only be compacted by compression. The volume decreases with an increase in water content, for the experiment a reduction of 61 %, until the cavities in between the fibres have all been water filled, shown at point A in Figure 14. Further water will expand the cavities and hence lead to a volumetric increase. This naturally leads to a relation between the water content and the bulk density of the paper fibres, which are approximately 35 kg/m3. Referring to section 6.4.5, it is essential to remember that the f.l.s.s.d.-density does not refer to the density of the pulp, but to that of a single f.l.s.s.d.-stated fibre, or a f.l.s.s.d.-stated pulp where all air cavities have been forcible removed, e.g. by compression.

Figure 14. Principled relation between water content and pulp volume. The blue hatched area after the extreme point of minimal volume indicates that the cavities in between the fibres have all been water filled and additional water therefore results in volume increase.

When the pulp is vibrated or stamped, a spring effect seems to take place, indicating that the fibres, instead of packing within themselves, springs on each other and maintains the volume. This effect is expected to happen due to the geometric nature of the fibres and the low density of the f.l.s.s.d.-stated paper pulp.

6.3.7 Sources of error and concise conclusion There are no obvious sources of error in the testing. In general, the experiment seeks to make visual observations and is therefore not particularly scientific, nevertheless of high importance.

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It is evident that an effective volume reduction can only be obtained by compression. The air content of the pulp is high, and cannot be reduced significantly using stamping or vibration. If compression is not to be used, these air cavities must therefore be water filled in the mortar mixing in order to secure the cement’s access to water for the hydration process. This inevitable leads to a high water content, resulting in high cement usage if the w/c- ratio is to be kept below 1.2. This will eliminate the economic incentive for using paper fibres in the bricks. Conclusively, paper fibre based bricks can only be formed using compression.

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6.4 Determination of fibre and lumen saturated outer surface dry state and density of paper fibres 6.4.1 Scope The scope of this testing is to determine the fibre and lumen saturated outer surface dry state (f.l.s.s.d.-state) and the coherent density of paper fibres from Papiruld Danmark ApS. The experimental setup and method is derived from that of determining of density of sand in saturated surface dry state (s.s.d.). Based on discussion with Associate Professor Staffan Svensson, appendix 5, and Associate Professor Mette Geiker, the following method is derived and the supporting theory evaluated. The aspects given special concern in deriving the method is explained in the following when relevant. The f.l.s.s.d. density is essential in the mortar formulation, as the water content must be adjusted coherent to the water amount absorbed by the paper fibres.

6.4.2 Determining fibre and lumen saturated surface dry- state for paper fibres To determine the s.s.d.-state for sand a standardised method is used [21]. The method includes a soaking and drying cycle, finishing with visual detection of s.s.d. state, Figure 15.

Figure 15. Sand grain in s.s.d. condition. The grain is saturated, but the surface is dry [21]

This visual detection is very inaccurate and practically impossible for paper fibres. Therefore the soaking and drying cycle must be avoided. As discussed in appendix 6, paper fibres total absorption ability is approx. 235 weight-%, including delivery moisture. The cell wall holds 35 weight-% and the lumen 200 weight % of water, relative to the fibres mass. When both are water filled, the fibres are in f.l.s.s.d. state. The f.l.s.s.d.-state corresponds to the s.s.d.-state of sand. Hence, a paper pulp in f.l.s.s.d.-state must be used in the testing, following the standardized method [21]. When 100 grams of paper fibres and 235 grams of water are mixed, corresponding to the mixing proportion of the f.l.s.s.d.-state, this state cannot be assumed to automatically take place, as illustrated in Figure 16.

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Figure 16. Left: Fibres in f.l.s.s.d.–state. All water is kept inside the cell walls and lumen. Right: Fibre pulp with water content equal to that of f.l.s.s.d. –state, but water is partly inside the cell walls and lumen, partly in between the fibres.

Nevertheless, the mass of the pulp to the right is equal to that of the corresponding f.l.s.s.d.-state to the left, mf.l.s.s.d., and is used so in the experimental calculations below.

6.4.3 Water absorption in cellulose fibres dependency on time Before determining the f.l.s.s.d. density, the time before soaked fibres reach the f.l.s.s.d.-state should be addressed. For the cell lumen, the time aspect is related to the theory for capillary suction. For the cell wall, the time is depending on hydrogen bonding. The relevant theory and consequences for the water absorption in cellulose fibres dependency on time is given in appendix 7.1. From appendix 7.1, the f.l.s.s.d.-state is obtained after no longer than 45 minutes. In the following experimental procedure, the paper fibres were left soaked overnight for 23 hours.

6.4.4 Experimental setup and procedure The testing equipment and setup is shown in Figure 17. A 2000 ml flask with 20 ml graduation is places on a horizontal surface. The flask has a diameter of 82 mm. The flask is filled with 2000 ml distilled water, and the mass of flask and water, m0 is measured. The exact volume of the water amount is not of importance for the testing, but it is essential that the exact same level can be re-established. Because of the relatively large flasks radius of 41 mm, the brim angle, θ, of the water surface is close to zero, and hence a water level can easily be fixed. In the testing, the brim is levelled with the upper side of the 2000 ml line, Figure 17.

Figure 17. Left: Testing equipment and setup. Right: Levelling of brim with upper side of 2000 ml line. Level can easily be re-established.

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The flask is emptied and dried thoroughly. The flask is places on the scale and the scale is reset to zero. With respect to section 6.4.2, 32 grams of paper fibres are put into the flask along with a water amount equal to that of f.l.s.s.d.-state. The mass of paper fibres and water is shown in Table 6. The water mass is adjusted for delivery water content derived in section 6. weight- %,

Adjusted weight- %,

relative to dry paper weight

relative to paper on delivery

weight [g]

mpaper fibres mwater

32,0 235,00

226,31

72,4

mf.l.s.s.d.

104,4 Table 6. Mass of paper fibres and water. Water mass is adjusted for delivery moisture content, 8.7 weight-%.

Additional water is added to the flask till it is almost full. The content is stirred till all possible air is driven out of the paper fibres. With respect to section 6.4.3, the flask is now left still for 23 hours to allow the fibres to be saturated. After 23 hours, the flask is stirred carefully, driving potential air inside the flask to the surface. The flask is again filled with water to the exact same level as earlier in the testing, Figure 17, and the mass of flask, water and saturated paper fibres, m1 is measured.

6.4.5 Derivation of fibre and lumen saturated outer surface dry density, Ď f.l.s.s.d. Firstly, it is important to remember that the Ď f.l.s.s.d. as well as Ď s.s.d. for sand, is a grain density or rather a fibre density, and is therefore not to be confused with a bulk density for a given sample of fibres in f.l.s.s.d.-state. The fibre and lumen saturated outer surface dry density can be derived from Equation 2. đ?‘šđ?‘“.đ?‘™.đ?‘ .đ?‘ .đ?‘‘. đ?œŒđ?‘“.đ?‘™.đ?‘ .đ?‘ .đ?‘‘. = ∗ đ?œŒđ?‘¤ đ?‘šđ?‘“.đ?‘™.đ?‘ .đ?‘ .đ?‘‘. + đ?‘š0 − đ?‘š1 Equation 2

3

Ď w is the density of water [kg/m ]. At 20 °C and 1 atm. pressure, Ď w is 998 kg pr. m3. The water temperature at testing time was 23.9 °C. In the calculations, Ď w is set to 1000 kg pr. m3. mf.l.s.s.d. is found from Table 6. In appendix 7.2, Ď f.l.s.s.d. is calculated to 1122 kg pr. m3.

6.4.6 Discussion The f.l.s.s.d.-density is of high importance for the experimental mortar design for the paper fibre based bricks. It has direct influence on the mortar mixing and therefore an essential prerequisite for making useful mortar formulas. As a theoretical control of the results, the solid state density, Ď s, of water and paper fibres can be used. Relative to their adjusted mass percentage of paper fibres in f.l.s.s.d.-state, 100.00 % for paper fibres and 226.31 %, for water, the theoretical f.l.s.s.d.-density can be derived from Equation 3 as a weighted average to 1153 kg. pr. m3. đ?œŒđ?‘“.đ?‘™.đ?‘ .đ?‘ .đ?‘‘. =

đ?œŒđ?‘ ,đ?‘¤ ∗ %đ?‘¤ + đ?œŒđ?‘ ,đ?‘?đ?‘“ ∗ %đ?‘?đ?‘“ %đ?‘¤ + %đ?‘?đ?‘“ Page 31 of 106

Equation 3

Where ﾏ『 [kg/m3] is the density of water, 1000 kg/m3 and ﾏ《,pf [kg/m3] is the solid state density of paper fibres, 1500 kg/m3 [4], %w [%] is the mass percentage of water and %pf [%] is the mass percentage of paper fibres.

6.4.7 Sources of error Equation 2 is sensitive to variations of the masses involved in the equation and therefore also reliant on a precise measurement of the water levels described in section 6.4.4. If the water level was misread in the last phase of the experiment with e.g. 3 ml too much, equalling 3 g, the derived f.l.s.s.d.-density would change from 1122 kg/m3 to 1160 kg pr. m3.

6.4.8 Concise conclusion

The f.l.s.s.d.-density is concluded equal to 1122 kg pr. m3. This density is used in the mortar formulation.

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6.5 Determination of sieving curves for 0-4 mm sand 6.5.1 Scope The scope of the experiment is to secure that the sand data used in the experiments, represents the actual sand used in the foundry. Special relevance refers to the theory of specific surface dependency on particle size’s increasing importance at particle sizes smaller than 1 mm, section 6.6.5.

6.5.2 Experimental setup, apparatus and procedure To get a representative sample, approx. 4 kg of sand is taken evenly from the container. The sand is dried for 24 hours at 105°C. The sand is then subdivided using a sand divider, Figure 18, until a representative sample between 100 grams and 200 grams is obtained. The sample is then shaken through a sieve pillar, Figure 18. When sieving is completed, the results are noted and the cumulated fall through percentage derived for each sieve. Finally, the results are shown graphically as the sieving curve. Container 1

4.0 2.0 1.0 0.500 0.250 0.125 <0.125

Container 2 Figure 18. Left: Sand divider from above. Blue arrows display how sand is divided into two representative samples of roughly equal mass. Middle: Sand divider from the side, while sand is being poured, falling into one of the two containers. Right: Sieve pillar. The sieves from the top are: 4.0 mm, 2.0 mm, 1.0 mm, 0.500 mm, 0.250 mm and 0.125 mm. In the bottom, a tray collects particles smaller than 0,125 mm. The pillar vibrates at a fixed frequency for 10 minutes.

6.5.3 Derivation of sieving curves for 0-4 mm lake sand and conclusion Results are given in appendix 3. From the sieving curve, the average particle size is derived to 0.4 mm, as shown in the sieving curve, Figure 19. The curve slope indicates that biggest percentage of particles, roughly 60 % - 25 % = 35 %, is in the interval between 0.250 mm and 0.500 mm.

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Sieving curve 100 90

Fall through, weight %

80

70 60 50 40 30 20 10 0

0,125 0,25

0,1

0,5

Sand

11

2

4

Sieve width mm

8

10

16

32

64

100

Stones

Figure 19. Sieving curve for 0-4 mm lake sand. Blue line indicates average particle size, 0.4 mm

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6.6 Consideration on geometry related conditions for setting of paper fibre based cement mortar 6.6.1 Scope The hydration of cement in general is dependent on the access of water. Furthermore, the mortars internal geometric circumstances has impact on the cements ability to set, which makes these circumstances vital for successful production of paper fibre based bricks. In this section, the general difference between a traditional cement based mortar or concrete and a paper fibre based mortar is evaluated and quantified. The relationship between the aggregate size and geometry and the setting ability of the mortar is discussed. Further, circumstances related to the paper fibre based brick mortar are investigated thoroughly. Ultimately, general advises for composing high content paper fibre based mortars in derived.

6.6.2 Identification of special considerations - comparison between traditional and paper fibre based mortars When cement sets, it happens because of the chemical hydration process. The pictures in Figure 20 are taken with a Scanning Electron Microscope (SEM) [13]. They show the needle formed calciumsilicatehydrates that interconnect the cement particles.

Figure 20. SEM photographs of cement setting. Left: Rapid Cement that has not hydrated. Right: Rapid Cement hydrated for 6 days. Forming of needle shaped calciumsilicatehydrates happen as a result of the calciumsilicates contact with water [10].

Considering the potential length of the needles from Figure 21, the needle length can be estimated to equal the diameter of the cement particle, d [m]. The average diameter of cement particles in Portland Basis cement is 15*10-6 m. Based on this, and securing an effective overlap between neighbouring particles’ needles, the critical distance, dcrit, allowed between cement particles in the mortar can be estimated equal to the average diameter of the cement particles, illustrated in Figure 21.

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Figure 21. Left: Estimated relation between particle size and needle length. Right: Estimated relation between particle size and critical particle distance to secure sufficient contact potential, 15*10 -6 m [10]

As the cement particles ideally are evenly distributed over the mortars internal specific surface, the specific surface is of high importance when evaluating the inter particular distances and hence the setting ability. The larger specific surface, the longer inter particular distance.

6.6.2.1 Identification of insufficient calciumsilicatehydrates - needles overlap To confirm the above theory of insufficient needle overlap between the cement particles, early mortar samples were photographed with a Nikon stereo microscope and investigated. These did in fact not have any or very poor setting abilities, Figure 22. The mortar used had 280 kg/m3 of water and 290 kg/m3 of cement. The aggregate was 25 vol-% 0-4 mm sand and 75 vol-% paper fibres. 1 2 3

Figure 22. Nikon stereo microscope photography taken at photo laboratory, BYG•DTU. Ruler numbers are in millimetres. 1: Single cellulose fibre. With a close look, cement particles and calciumsilicatehydrate needles can be observed on the surface as small “bumpsâ€?. 2: Joint of several paper fibres effectively joined by calciumsilicatehydrate needles. 3: Sand grain, seemingly unconnected to its neighbouring particles and fibres.

The picture reveals that even though the cement has hydrated, the cement particles are insufficient to obtain sufficient inter particular connections. The zoom level is not high enough to analyse the cement particles and calciumsilicatehydrate needles, but

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they can however be identified as small “bumps� on the paper fibres surface. Section 8.8.4 analyses the needles with SEM photographs.

6.6.3 Specific surface in traditional mortar or concrete and paper fibre based mortars Figure 23 shows a volumetric example of aggregate compositions for traditional and paper fibre based mortars. The cement paste constitutes 25vol-% and the aggregate 75 vol-%, and 65 vol-% respectively, for the traditional and paper fibre based mortars.

Figure 23. Volumetric example on composition of traditional and paper fibre based cement mortar/concrete.

Before addressing the specific surface difference of the two mortars in Figure 23, a volumetric observation must be made. The volume of the stones in the traditional concrete can be described as passive volume. This indicates that the stone internal volume does not need the cements setting abilities as it is already solid. Hence, the spatial concentration of cement particles on the surface of the aggregates will increase with bigger particles. This fact is, in essence, the link between the specific surface of the aggregates, and hence the setting abilities of the mortar. For any given particle, the specific surface in depending on the geometry, and will be evaluated for sand and cellulose fibres in the following.

6.6.3.1 The specific surface for sand The sieving curve for the used 0-4 mm lake sand is derived experimentally in section 6.5. The sieving curve is shown in appendix 3. The average grain size is derived as 0.4 mm. The specific surface of a sand particle in s.s.d.-state, Ssand [m2/kg] for an average grain size of 0.4 mm can be derived from Equation 4 to 5.7 m2/kg. The s.s.d.-state is to be used because the pores in the sand are assumed empty of cement. đ?‘†đ?‘ đ?‘Žđ?‘›đ?‘‘

đ?‘†đ?‘˘ 4đ?œ‹đ?‘&#x; 2 6 = = = đ?‘š 4 đ?œ‹đ?‘&#x; 3 ∗ đ?œŒ đ?‘‘ ∗ đ?œŒđ?‘ .đ?‘ .đ?‘‘. đ?‘ 3

Equation 4

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Where Su [m2] is the surface of a spherical sand particle, m [kg] is the mass, r [m] is the radius and d [m] is the diameter of the particles. Figure 24 shows the correlation between the specific surface and diameter for sand with an s.s.d.-density of 2650 kg/m3.

2

S [m2/kg]

Relation between diameter and specific surface, particulate materials 2,5

1,5

1 y = 2,3077x -1 R² = 1

2650

Power (2650)

0,5

0 35

30

25

20

15

10

5

0

Diameter [mm]

Figure 24. Specific surface as a function of the particle diameter for sand with a solid density of 2650 kg/m. The powered equation is given next to the trend line.

The graph equation reveals that a halving of the particle diameter induces a doubling of the specific surface.

6.6.3.2 The specific surface for paper fibres When considering cellulose fibres’ specific surface in a mortar, the volume of a cylinder is used as a reference, Equation 5. The f.l.s.s.d.-state is used, based on the same assumption as for sand. This excludes the internal surface of the fibre wall from the specific surface. đ?‘†đ?‘˘ 2đ?œ‹đ?‘&#x;đ?‘• đ?œ‹ đ?‘†đ?‘“đ?‘–đ?‘?đ?‘&#x;đ?‘’ = = 2 = đ?‘š đ?œ‹đ?‘&#x; đ?‘• ∗ đ?œŒđ?‘ đ?‘&#x; ∗ đ?œŒđ?‘“.đ?‘™.đ?‘ .đ?‘ .đ?‘‘. Equation 5

Where h [m] is the cellulose fibre length and r [m] is the radius of the fibres. For a cellulose fibre of 3,5 mm length and a diameter of 30 Âľm [11] with a f.l.s.s.d.-density of 1122 kg/m3, as found in 6.4.5, the specific surface becomes 186.7 m2/kg.

6.6.3.3 Specific surface for mixed aggregates When aggregates of different types are used in a mortar, the mortars specific surface can be derived as a weighted average from Equation 6, weighted by the aggregates gravimetric part of the mortar. đ?‘†1 ∗ đ?‘š1 +đ?‘†2 ∗ đ?‘š2 +đ?‘†3 ∗ đ?‘š3 ‌ . +đ?‘†đ?‘› ∗ đ?‘šđ?‘› đ?‘†đ?‘šđ?‘œđ?‘&#x;đ?‘Ąđ?‘Žđ?‘&#x; = đ?‘š1 + đ?‘š2 + đ?‘š3 ‌ . +đ?‘šđ?‘›

Equation 6

Where S1-n [m2/kg] is the specific surface for the different aggregates and m1-n [kg/m3] is the relative mass of the aggregates in the mortar.

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6.6.3.4 Comparison between specific surface of traditional mortar and paper fibre based mortars Based on the findings in section 6.6.3.1 to 6.6.3.3, the specific surface can be compared for a sand only (mortar SA) and a sand and paper fibres mortar (mortar P), where the fibres constitute 50 vol-% of the aggregate. For both formulas, the water content is fixed to 290 kg/m3 and the cement content to 290 kg/m3, so the aggregates volumetric part of the mortar is the same for both. The formulas used are shown in appendix 8. In appendix 9, the specific surface is derived to 5.7 m2/kg for mortar SA and 59.5 m2/kg for mortar P, giving the mortar P with 50 vol-% paper fibres an internal specific surface more than 10 times larger than mortar SA, which only contains sand.

6.6.4 Discussion In order to evaluate the cements geometry related setting potential, the critical distance, dcrit, between the cement particles, shown in Figure 21, is compared with the actual distance between the cement particles in mortar SA and mortar P, dact. The criterion for sufficient setting potential is then given in Criteria 1. đ?‘‘đ?‘Žđ?‘?đ?‘Ą < đ?‘‘đ?‘?đ?‘&#x;đ?‘–đ?‘Ą = đ?‘‘

Criteria 1

To determine the actual distance between cement particles, the average cement particle mass, mp [kg] and the number of cement particles pr. kg cement, np [kg-1] must first be derived. 4 đ?‘šđ?‘? = đ?‘‰đ?‘? ∗ đ?œŒđ?‘ = đ?œ‹đ?‘&#x; 3 ∗ đ?œŒđ?‘ 3 1 1 đ?‘›đ?‘? = = = đ?‘šđ?‘? −1 đ?‘‰đ?‘? ∗ đ?œŒđ?‘ 4 đ?œ‹đ?‘&#x; 3 ∗ đ?œŒ đ?‘ 3

Equation 7

Equation 8

From Equation 7 and Equation 8, and using the average diameter of cement particles in Aalborg Portland Basis cement, 15*10-6 m and a solid density, Ď s, of 3100 kg/m3, the average cement particle mass, mp, can be derived as 5.5*10-12 kg. The average particle number, np, pr. kg Aalborg Portland Basis cement to 182.5*109 kg-1. The cement particle number and specific surface of a given mortar is then used to derive the average actual distance between two neighbouring particles. The situation is shown in Figure 25.

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Figure 25. Principled display of situation of evenly distributed particles, indicated by black dots, and distance, d, between particles. Number of particles, n=26. Total area, A=24a2.

From geometric studies, the actual distance can be expressed by the total area and particle number by Equation 9. For the principled situation in Figure 25, đ?‘‘đ?‘Žđ?‘?đ?‘Ą = 2đ?‘Ž, which corresponds with Pythagoras theorem. đ?‘‘đ?‘Žđ?‘?đ?‘Ą =

2∗

đ??´ đ?‘› Equation 9

To apply Equation 9 to mortar SA and mortar P, the total area, A, is substituted by the specific surface. The number of particles, n, is the number of cement particles in the mortar. As the cements relative percentage of mortar SA and mortar P depends on the aggregate, n is found as follows: From appendix 8, the cement constitutes 13 mass-% in mortar SA, therefore n = 0.13 * np = 0.13 * 182.5 * 109 kg-1 = 24.0*109 kg-1. In mortar P, the cement constitutes 17 mass-%, therefore n = 0.17 * np = 30.5*109 kg-1. The actual distance can then be derived from Equation 9 to 7.9 ¾m for mortar SA and 25.5 ¾m for mortar P. Detailed calculations are shown in appendix 9. This indicates that mortar P will have poor or no setting abilities, as the particle average distance is more than the critical distance from Figure 21, 15*10-6 m. In order to secure sufficient setting abilities, passive volume in the form of stones could be added to mortar P in order to substitute some of the paper fibres and hence lower the aggregates specific surface and hereby the particle distance. In appendix 8, the formula for a third mortar ST is given. It contains 50 vol-% 0-4 mm sand, 31 vol-% 4-8 mm stones and 19 vol-% paper fibres. It is of absolute importance to remember that the 19 vol-% paper fibres are in f.l.s.s.d. state. The coherent vol-% of dry paper fibres is 3.7 vol-%. In order to meet general demands for biggest allowed stone size [8], the stones’ diameter must not exceed 1/5 of the smallest brick dimension. The brick height is 70 mm. Hence only 4-8 mm stones can be used in the production.

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The average diameter for the stones is derived from appendix 3 to 5.8 mm. From appendix 9, the actual distance then becomes 14.9*10-6 m, which respects the critical distance of 15.0*10-6 m.

6.6.5 Sources of error The geometry of a cellulose fibre varies with many different parameters, and is therefore unique between samples. This has potential importance for the specific surface. Nevertheless, this source of error is considered minor, as the geometry used is an average. The trend line in Figure 24 has the equation S=2.3*d-1. This indicates that the specific surface only changes slightly with geometry deviations for the sand and stones. Therefore the potential geometry source of error is considered relevant for the paper fibres only. A similar source of error should be noted concerning the cement particle size. A diameter reduction will result in a particle number increase, reducing the actual distance found from Equation 9. The relation between the actual distance and the diameter for mortar ST is shown in Figure 26. Relation between actual distance and particle diameter (critical distance) 140,0E-6

Actual distance, dact [m]

120,0E-6 100,0E-6 80,0E-6 60,0E-6 40,0E-6 20,0E-6

y = 9E-08e 1,0397x R² = 1

15*10^6 m

000,0E+0 1,0E-6

2,0E-6

4,0E-6

8,0E-6

Particle diameter, dcrit, [m]

16,0E-6

32,0E-6

64,0E-6

15*10^6 m

Figure 26. Relation between actual distance and particle diameter.

From the figure, it can be seen that around the average particle diameter, 15*10-6 m, tangent indicated by red line, dcrit ≈ dact. This rough approximation reduces the impact of this source of error significantly. With a different type of cement with a larger cement particle size, this source of error could have heavy impact. The source of error with the highest potential impact is that of Figure 21, indicating that the needle length is equal to the particle diameter. If, for instance, the needle length in mortar ST is actually only half the particle diameter, Criteria 1 would change to Criteria 2 below đ?‘‘đ?‘Žđ?‘?đ?‘Ą < đ?‘‘đ?‘?đ?‘&#x;đ?‘–đ?‘Ą = 0.5 đ?‘‘ Criteria 2

In order to fulfil Criteria 2, mortar ST should reduce the paper fibre content in the aggregate to 2.5 weight-%, and 47.5 weight-% 4-8 mm stones.

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6.6.6 Concise conclusion

The particle distance must not exceed the critical distance, 15*10-6 m. Stones of size 4-8 mm can be used as passive volume to secure this. Provided that the sand weight-% is no less than 50, this reduces the weight-% of paper fibres in f.l.s.s.d state to 19 vol-% or 3.7 vol-% of dry fibres. The mortar aggregate should be composed coherent.

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6.7 Determination of slump dependency on free water content in paper fibre based cement mortar 6.7.1 Scope The purpose of the section is to determine the paper fibre based cement mortar slumps dependency on the water content and aggregate composition. The experiment is needed to determine how the workability changes with the free water content for the paper fibre based cement mortar. The experiments usefulness relies on Lyses’ Law on the workability’s independence from the cement content and water/cement- ratio in cement based mortars and concretes. The experiment is performed for two different aggregate compositions between paper fibres and sand: 1. Paper fibres 75 vol-% and sand 25 vol-% 2. Paper fibres 50 vol-% and sand 50 vol-% The experimental setup and procedure is identical for both aggregate compositions.

6.7.2 Lyses’ law and general considerations for free water in paper fibre based cement mortar The consistency of any given fresh cement mortar is solely determined by the content of free water and not the absolute water content. Hence, the consistency is independent from the cement content and water/cement-ratio. This fact is defined as Lyses’ law. With a higher content of free water, the fluidity of the mortar increases. The free water content needed for the mortar to obtain a certain consistency depends on the size, shape and surface of the aggregates. Big, round and smooth particles generally require the least free water.

6.7.3 Experimental setup and apparatus To determine the slumps dependency on the water content, two mortars of given formulas with a low slump is used as point of reference. The formulas used are given in appendix 10. They have an initial free water content of 230 kg/m3. This initial water content was chosen as initial mortar testing showed that a free water content less than 230 kg/m3 had no utility, as the mortar would become too dry. A free water content of 230 kg/m3 is also the upper limit for conventional concrete when using small aggregates (8 mm to 10 mm) and high slumps (100 mm to 150 mm). On these bases, 230 kg/m3 of free water was chosen as initial content. The water/cement-ratio was 0.8 and an aggregate composition as described in 6.7.1. For the experiment, the slump measurement method, standardised in [9], is used. The procedure requires a levelled surface, a 300 mm truncated cone with a lower diameter of 200 mm and an upper diameter of 100 mm. A 16 mm round iron bar of 600 mm length is used for stamping, Figure 27.

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Figure 27. Levelled surface, 300 mm truncated cone with a lower diameter of 200 mm and an upper diameter of 100 mm, 16 mm round iron bar of 600 mm length. Setup is photographed during testing; specimen is in the centre of the picture.

6.7.4 Experimental procedure In the following, the slump measurement method is described. This method is repeated in a series for different free water contents. To perform the slump measurement, the truncated cone is seated on the levelled, firm and not absorbent surface and filled with mortar in three rounds. For each round, approx. 100 mm is filled. After each round, the mortar is stamped 25 times with the iron bar. When the cone is full, excessive concrete along the top edge is scraped off, and the cone lifted. The distance that the mortar sets, that is the difference between the cones height, 300 mm, and along the sunken cone, is the slump in millimetres, Figure 28.

Figure 28. Sketch of the principle of the slump measurement method.

After measuring the slump of the formulated mortar, water is added to the mortar in portions of 250 ml, 500 ml or 1000 ml. After each water portion, the mortar is mixed again, and the slump measurement repeated. This was repeated until the slump was greater than 60 mm. Halfway through the series; a new mortar was mixed, similar to that of the previous slump measurement. This was done to secure that too much water Page 44 of 106

didn’t vaporise and that small amounts of mortar dropped during the experiment didn’t inflict on the results.

6.7.5 Water/cement-relation change By using the procedure in section 6.7.4, the water/cement-ratio changes for each added portion of water, because the cement amount is fixed from the initial formula. Nevertheless, the experiment gives a valid indication of the relation between the water content and the slump. This is because of Lyse’s Law.

6.7.6 Derivation of slump dependency on the water content The results are given in appendix 11. For each added portion, the appurtenant water content can be derived as follows. Based on the previous target volume of the mortar and the added portion of water, the adjusted volume of the mortar is can be calculated from Equation 10. đ?‘‰đ?‘Žđ?‘‘đ?‘— = đ?‘‰đ?‘?đ?‘&#x;đ?‘’đ?‘Ł + đ?‘¤đ?‘Žđ?‘‘đ?‘‘đ?‘’đ?‘‘ Equation 10

Where Vadj [l] is the adjusted target volume, Vprev [l] is the volume of the previous mortar and wadded [l] is the added water amount. Using this, the water content in kg pr. m3 can be calculated đ?‘¤đ?‘Žđ?‘‘đ?‘— đ?‘¤đ?‘šđ?‘œđ?‘&#x;đ?‘Ąđ?‘Žđ?‘&#x; = đ?‘‰đ?‘Žđ?‘‘đ?‘— Equation 11

Where wmortar is the water content of the mortar [kg/m3], and wadj [l] is the adjusted water content pr. target volume. The water contents and the appurtenant slump measurements are shown in Figure 29. The figure also shows a reference graph for conventional sand and stones based concrete mortar.

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Slump dependency on the water content 140

Measured slump [mm]

120 100 80 Pf/Sa 50/50

60

Pf/Sa 75/25

40

reference

20 0 150 200 250 300 350 400 450 500 550 600 650 700

water need [kg/m3] Figure 29. Water content and appurtenant slump levels from the experimental findings. Reference graph [8] for lake materials of a maximum diameter, dmax, of 8 mm to 10 mm.

6.7.7 Discussion Figure 29 shows that the slump is depending on the water content as expected, but also that paper fibre based aggregates in general has a much higher water need to obtain a given slump than sand and stone based aggregates. The ratio between paper fibres and sand in the aggregate is of importance. E.g., at a water content of 550 kg/m3, the mortars with 75 % and 50 % paper fibres slumps 16 mm, respectively 56 mm. The supporting theory for these observations is discussed in section 6.6. To obtain similar slumps, the conventional reference mortar needs approx., 160 kg/m3, and 185 kg/m3. The practically obtainable slump interval for the used mortars is 10 mm – 60 mm. However, at high water content levels, the mortars started giving off free water when resting in the bucket. Founded in Bolomey’s law on the relation between the w/c-ratio and strength in conventional concrete theory [10], a w/c-ratio higher than 1.2, referring to low – strength concrete, is rarely used. This indicates that w/c-ratios should not exceed 1.2. If this theory is applied to the paper fibre mortar, it carries heavy consequences, example: Using Figure 29, a 30 mm slump on a 50 % paper fibres mortar requires approx. 525 kg/m3 of water, constituting a cement need of 525 kg/m3 / 1.2 = 437.5 kg/m3 of cement. When mixed in a paper fibre based mortar with a density of typically 1300 kg/m3, this only allows for 1300 kg/m3 - (525 kg/m3 + 3 3 437.5 kg/m ) = 337.5 kg/m of aggregates, or 26 mass- %. As a reference, a conventional concrete mixture with the same requirements for slump and w/c-ratio will have a water need of 180 kg/m3, and hence a cement need of 150 kg/m3 [10]. With a typical density of 2300 kg/m3, this allows for 2300 kg/m3 - (180 kg/m3 + 150 kg/m3) = 1970 kg/m3, equal to 85 mass-%.

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6.7.8 Sources of error The slump method itself carries a natural inaccuracy. In general, slump measurements are for guiding purposes, and not precise. Likewise, this experiment has a natural inaccuracy and results should be used as guidelines. Because the air content, need and slump are interrelated, the formulas used for the mortars assume an air content of 0.01 %. This assumption is based on a best bet from previous observations. During the experiment, an amount of water dripped down from the testing table. This water loss was approximated and sought compensated for during the experiment by adding small amounts of extra water. Also, small amounts of mortar were dropped during the experiment. When possible, these were put back in the mortar. To ensure minimal impact, a new mortar was mixed halfway through the series, as mentioned in 6.7.4.

6.7.9 Concise conclusion With respect to minimizing the free water that is given off when the mortar rests, and to maintain the bricks strength potential, the slump cannot exceed 10 mm. This constitutes a water need for the 50 % and 75 % paper fibres aggregates of 460 kg/m3, respectively 500 kg/m3. At these water levels, using a maximum w/c- ratio of 1.2, aggregates constitute no more than 35 %. The lower limit of the free water content is 230 kg/m3. The upper limit is 348 kg/m3. Using a w/c-ratio no higher than 1.2, the economical incentive of using high amounts of paper fibres can only be retained if the water need is lowered to 348 kg/m3, requiring a cement need of 290 kg/m3. Generally, paper base cement mortars can be concluded to slump far less than conventional cement mortars. Conclusively, production methods relating to shaping cannot rely on slump. This supports the concise conclusion from section 6.3.

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6.8 Concise conclusion of chapter 6 Based on the testing and experiments in chapter 6, the following is concluded. To form the paper fibre based bricks and secure hydration, compression must be used when forming the bricks. Apart from this, a series of technical findings are listed in Table 7. Table 7. Preproduction findings for the paper fibre based bricks Name Symbol Measurement Reference Water content of paper fibres u 8.7 % 6.2.4 from Papiruld Danmark ApS Fibre and lumen saturated outer Ď f.l.s.s.d. 1122 kg/m3 6.4.8 surface dry density Maximum water/cement-ratio w/cmax 1.2 6.7.9 with economical incentive Maximum cement content in 290 kg/m3 3.3.2.2 mortar Maximum vol-% of paper fibres 19 % in f.l.s.s.d. state 6.6.6 in aggregate* 3.7 % in dry state Minimal free water content in 230 kg/m3 6.7.9 mortar Maximal free water content in 290 kg/m3 6.7.9 mortar * Based on an aggregate composition with 50 vol-% 0-4 mm sand and 31 vol-% of 4-8 mm stones. Table 7. Findings from preproduction testing and experiments.

Based on the above conclusions, a window of opportunity can be derived, Figure 30. The window will be used in section 7 for derivation of paper fibre based brick production formula and method.

Figure 30. Window of opportunity. The level of cement is fixed to 290 kg/m3. The free water content and water/cement-ratio is interdependent. The hatched area is the window of opportunity, within which the paper fibre based bricks are concluded to have useful setting abilities.

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7 Derivation of paper fibre based brick production formula and method In this section, the formula and production method is finalized. Based on these, a series of testing specimens will be produced. These are to be used for the following experiments for material properties. To suit the requirements of the experiments to be performed, bricks of different dimensions were produced. The dimensions are given in sections regarding the individual experiments.

7.1 Production formula From the window of opportunity, Figure 30, the chosen terms are indicated by yellow circle. The dry paper fibre content is optimized to 3.7 vol-%. The w/c-ratio is 1.0 and hence the free water and cement content 290 kg/m3. The formula is given in appendix 12.1. The curing process’ requirement for dry paper fibre content no larger than 3.7 vol-% is relatively low compared with the initial experiments. Therefore the name paper fibre based bricks was considered misleading. On this basis, a new name was formed, Cement and Cellulose based bricks, shortened to CEMCEL Bricks. The name, CEMCEL Bricks, will be used throughout the remaining report.

7.1.1 Production method

7.1.1.1 Mixing In the mixing process, a simple Starring cement mixer was used. The machine can mix 15 litres of mortar at the time. In principle, the mixing could easily be performed by hand driven machinery or even mixed with a shovel.

Figure 31. Staring cement mixer.

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7.1.1.2 Forming For the forming procedure, formwork was produced locally at the workshop at the Department of Civil Engineering, Technical University of Denmark. In the following, the formwork for producing the actual brick, measuring 22 cm x 10 cm x 7 cm is presented and explained. Special formwork for producing special specimens customized for experiments in the following is shown as pictures in Appendix 12.2, the sketch for the brick formwork is shown in Figure 32.

Figure 32. Design sketch for the brick formwork. This sketch was given to the carpenter in the workshop.

After the preproduction experiments, another small experiment was performed, considering two circumstances:  In order for the production method to be simple and low tech, it had to be easy to identify, when the mortar was sufficiently compressed.  Referring to section 6.3.7, all air cavities in the mortar must be water filled during compression to secure the hydration process’ access to water. Very practically, these two circumstances solve one another. When the air cavities are water filled because of the compression, the mortar will give off free water. This can easily be visually detected, see pictures in appendix 12.2. Therefore, an additional preproduction experiment was performed. Using the CEMCEL Bricks formula, and a similar reference formula with a w/c-ratio of 1.2, the relation between the w/c-ratio and the compression percentage before the mortar spilled free water was investigated, Figure 33.

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Estimated relation between w/c- ratio and compression before water spillage 30% 25% 20% 15% 10% 5%

0% 1,4

1,3

1,2

1,1

1

Compression percentage [%]

35%

Measured points Liniar estimated

w/c- ratio [-]

Figure 33. Relation between w/c- ratio and compression percentage before free water spillage.

For the CEMCEL Bricks mortar, free water was spilled when the mortar was compressed by 33 %. This compression level was used in the production. This method to identify the compression level was seen to be very consistent and easy to work with. Figure 34 shows the hydraulic compression machine used. The compression load did not exceed 1 kN, or 100 kg. Therefore similar compression could easily be performed using manual machinery.

Figure 34. Hydraulic compression machine. The compressing was performed using a foot- pedal. In the picture, the CEMCEL Bricks are being produced, using the produced formwork.

7.1.1.3 Curing The curing process should be in climatic conditions representative to those in Hyderabad India. Therefore a climate chamber was customized for the project, Figure 35.

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Figure 35. Climate chamber customized for the project. The temperature is fixed at 32 째C. An ultrasound humidifier was setup but not used, as the specimens were packed in water containing plastic bags.

After forming, the specimens were left in the formwork. The formwork was put in sealed plastic bags. Inside the plastic bags, additional water was poured to secure a humidity of 100 % RH. After two days, the CEMCEL bricks was taken out of the formwork and put back in the plastic bags at 100 % RH. Therefore, the humidity in the chamber did not have to be fixed. In total, the CEMCEL Bricks was left to cure in 45 days. A cured CEMCEL Brick ready for building is shown in Figure 36.

Figure 36. CEMCEL Brick ready for building. Measurements 220 mm * 100 mm * 70 mm.

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8 Determination of material properties for CEMCEL Bricks In this chapter, the bricks are evaluated and analysed through its material properties and parameters. The purpose is to determine general, strength, heat and moisture related properties and parameters for the CEMCEL Bricks developed.

8.1 Material properties and parameters experimental plan The plan in order to determine the selected material properties and parameters is given in Figure 37.

Porosity and density General experiments

Capillary suction

Heat related experiments

Thermal conductivity

Moisture related experiments

Moisture related deformation and hysteresis

Strength related experiments

Compression strength and stress/strainrelation curve

Biological and structural experiments

Investigation of biological deterioration

Evaluation and input to conclusion

Analysis of microstructure and elemental composition

Figure 37. CEMCEL Brick material properties and parameters experimental plan.

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8.2 Porosity and density 8.2.1 Scope The scope of this section is to report the determination of the open porosity, solid density, dry density and saturated surface dry density. The testing is performed according to LBM- Prøvemetode 2, 6108/14.

8.2.2 Experimental setup and apparatus Specimens are wet cut from the bricks as shown in Figure 38, having approximate dimensions 52 mm * 70 mm * 100 mm.

Figure 38. The two specimens used for the porosity and density testing, P4-1 and P4-2. The dashed lines indicate how the specimens were cut out of the brick.

In order to determine the porosity, solid density, dry density and saturated surface dry density, the specimens must be vacuum saturated with water. This method used for porous materials, secures water filling of all open pores in the specimens. By weighing the saturated specimens above and below water, the open porosity, solid density, dry density and saturated surface dry density can be derived. The specimens are placed in a desiccator, Figure 39. Beforehand, the desiccator was smeared with desiccator grease between the bowl and lid, securing an airproof closure. The desiccator spigot is, via a rubber hose, connected to a vacuum pump. In between the desiccator and vacuum pump, a pressure gauge is inserted, indicating the vacuum that the pump provides.

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Figure 39. Photo of the experimental setup for vacuum saturation of the bricks. Left: The desiccator. Centre: The vacuum pump, pumping the air out of the specimens. Right: The pressure gauge.

8.2.3 Experimental procedure After cutting the specimens, these are placed in an oven (temperature, see below), until the mass of the specimens is constant over three subsequent days. They are then placed in a desiccator with silica gel under atmospheric pressure till they have cooled. Then weighed, and the dry mass, m0, determined. The specimens are now placed in the desiccator, Figure 39, and evacuated for three hours, ensuring that all air is extracted from the open pores. Then the vacuum is used to water fill the desiccator to 5 cm higher than the specimens. The temperature of the water and air is noted. The vacuum pump is turned on again, but carefully stopped when the vacuum reaches waters vapour saturation pressure, 2338 N/m2. This prevents the water from boiling, causing potential specimen breakage. This vacuum is kept overnight, till no further bubbling from the specimens can be visually observed, indicating full saturation. The desiccator spigot is now opened, and the specimens are left over night under atmospheric pressure. Finally, the specimens mass under water, muw [kg], is weighted. The specimens are surface dried with a hard wrung cloth, and the saturated surface dry mass, mssd [kg], is weighted. Because of the cellulose fibres potential damaging when dried in an oven at 105 °C, the test is performed in two phases, firstly preconditioned at 50 °C, secondly preconditioned at 105 °C. The testing procedure is the same for both. This approach should reveal potential “burning” of the cellulose fibres. The phases are named as follows: 1. Phase 1 – Specimen P4-1 and P4-2, preconditioned at 50 °C 2. Phase 2 – Specimen P4-1 and P4-2, preconditioned at 105 °C

8.2.4 Correlation between porosity and other properties The bricks are expected to have a relatively high porosity. This expectation is linked to the cellulose fibres swell and shrinkage properties when wetted, as well as aggregate surface behaviour in the setting process of mortars with a high amount of aggregate. This will be discussed in the following. Page 55 of 106

The porosity has high impact on the bricks other properties. Generally, open pores allow water to be absorbed, which means that high porosity materials are more exposed to changes in properties due to humidity changes. This includes strength, deformation and density. The porosity and density correlation is reversed linear, the higher the porosity, the lower the density.

8.2.5 Determination of porosity and density To determine the density, the bricks’ volume must firstly be derived, using Archimedes principle, Equation 12. đ?‘šđ?‘ đ?‘ đ?‘‘ − đ?‘šđ?‘˘đ?‘¤ đ?‘‰= đ?œŒđ?‘¤

Equation 12

The density of water, Ď w, is dependent on the temperature and pressure. For atmospheric pressure, it is set to 998.21 kg/m2, using matrix interpolation in [14], based on the water temperature during the testing, 20.1 °C. The dry density, Ď d [kg/m3] can now be derived from Equation 13, đ?‘š0 đ?œŒđ?‘‘ = đ?‘‰

Equation 13

The open porosity can be determined as the relation between the volume of the open pores and the total volume. The volume of the open pores, Vo [m3], can be found from Equation 14, đ?‘šđ?‘ đ?‘ đ?‘‘ − đ?‘š0 đ?‘‰đ?‘œ = đ?œŒđ?‘¤

Equation 14

Subsequently, the open porosity, po [%], can be presented by Equation 15, đ?‘šđ?‘ đ?‘ đ?‘‘ − đ?‘š0 đ?‘‰đ?‘œ đ?‘?đ?‘œ = = đ?‘‰ đ?‘šđ?‘ đ?‘ đ?‘‘ − đ?‘šđ?‘˘đ?‘¤

Equation 15

By assuming that all pores in the bricks are interconnected, which is common for porous materials, the solid density, Ď s [kg/m3], can be derived from Equation 16, đ?œŒđ?‘ − đ?œŒđ?‘‘ đ?œŒđ?‘‘ đ?‘? = đ?‘?đ?‘œ = ⇔ đ?œŒđ?‘ = 1 − đ?‘?đ?‘œ đ?œŒđ?‘

Equation 16

Where p is the total porosity [%]. Finally, the surface saturated surface dry density, Ď ssd, can be found from Equation 17, đ?‘šđ?‘ đ?‘ đ?‘‘ đ?œŒđ?‘ đ?‘ đ?‘‘ = đ?‘‰

Equation 17

8.2.6 Calculation Results and calculation of density and porosity testing is given in appendix 13. The average results for both phase 1 and phase 2 is shown in Table 8. po Ď d [kg/m3] Ď s [kg/m3] Ď ssd [kg/m3] Average Phase 1 34,1% 1682 2552 2022 Phase 2 36,0% 1664 2601 2024 Table 8. Average values for the open porosity, the dry density, the solid density and the saturated surface dry density of the brick.

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8.2.7 Discussion Generally, an important observation in results is high accordance between the specimens and phases. Furthermore, no faults or other compromising circumstances were observed during the testing. In the vacuum phases, the vacuum was held until no more bubbling could be observed visually. In all cases far longer time than suggested in the standards. These things combined solidities the testing results.

8.2.7.1 Open porosity The average open porosity is between 34.1 % and 36 %, Table 8. It is evident that the increased porosity in phase 2 is a direct consequence of the 105 °C drying. After drying, both specimens in phase 2 were exactly 6.6 g lighter (m105) than in phase 1 (m50), showing that the moisture content of the phase 1 specimens after drying is not zero, but 1.1 %, even though the specimens had reached mass equilibrium over three days. This remaining water is chemically bound in the bricks. In experimental practice however, 105 °C is used as the completely dry state reference. If using m105 instead of m50 in the phase 1 calculations, the porosity only differs from that of phase 2 by 0.06 %, Figure 40. This proves that 50 °C is not enough to completely dry the bricks. As explained in 8.2.3, concern is given to whether oven drying at 105 °C will damage the organic cellulose fibres. The above investigation also proves that 105 °C drying does not resolve in any measureable “burning” of the cellulose fibres, which increase the potential utility of the bricks. Based on the above, and the in section 8.2.7 described, the Phase 2 results will be used as in the following chapters as representative for the brick. Open porosity 36,50% 36,00% Phase 2

Porosity

35,50%

Phase 1 35,00%

Phase 1-2

34,50% 34,00% 33,50%

P4-1

Specimen

P4-2

Figure 40. Open porosity for phase 1, phase 2 and the theoretical phase 1-2, where the dried mass of phase 1, m105, is used in phase 2 instead of m50.

Comparing the open porosity with common materials [4], the CEMCEL Bricks have higher open porosity than concrete and cement mortar, but lower than high porosity materials, Figure 41.

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Porosity comparisment 90,00% 80,00%

70,00%

Cellular concrete, medium density

Wood, pine

10,00%

Lightweight concrete, constructions

20,00%

CEMCEL Bricks

30,00%

Cement mortar

40,00%

Hard burned bricks

50,00%

Concrete,w/c 0,6

Porosity

60,00%

0,00% Porosity

Figure 41. Porosity of common building materials [4].

Generally, the open porosity of the bricks must be considered relatively high. Figure 42 shows the principal for the bricks composition before and after curing.

Figure 42. Illustration of the composition of the brick before and after curing. The left vertical axis shows the composition of the wet mortar, yellow line being the cement paste, the blue line the aggregates. The right vertical axis shows the composition after curing, all porosity contributions marked with red.

Figure 42 indicates four porosity contributors, the initial air content, cement paste related porosity, cellulose fibre and sand and stone related porosity. This will be investigated in the following.

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8.2.7.1.1 Initial air content porosity The estimated initial air content of 1.0 % is expected unchanged during the curing process, 1.0 %. This is an estimated value because the wet mortar air content cannot be determined because the fibres are potentially hazardous to the equipment needed.

8.2.7.1.2 Chemical shrinkage and capillary water porosity During curing, chemical shrinkage, Vc.s. [%] will occur in the cement paste. The shrinkage depends on the hydration degree, Îą, and the w/c- ratio. For a = 1, indicating full hydration of the cement which occurs at w/c- ratios higher than 0.42, excessive water will remain, capillary water, Vc.w. [%]. After drying, the capillary water will leave cavities, contributing to the porosity. The chemical shrinkage and capillary water percentage of the initial cement paste volume can be estimated using Powers’ model, Equation 18 and Equation 19 [15]. đ?‘‰đ?‘?.đ?‘ . = 0,2(1 − đ?‘¤

Vc.w. = w

w

�

đ?‘? )đ?›ź đ?‘? + 0.32

w

c c )Îą − 1.3(1 − w + 0.32 + c c 0.32

Equation 18

Equation 19

Using the bricks w/c = 1.0, Vc.s. = 4.8 % and Vc.w. = 44.2 %. The cement paste constitutes 46 % of the total mortar. Hence, the total porosity contribution from the cement paste will be (4.8+44.2) % * 46 % = 22.6 %.

8.2.7.1.3 Cellulose fibre related porosity Naturally, the fibre lumens contribute to the porosity. The fibres lumen constitutes approximately 75 % of the fibre [11]. From the formula in appendix 12, the fibres constitute 3.7 % of the mortar in f.l.s.s.d.-state, consequently, the lumen results in 75.7 % * 3.7 % = 2.8 % porosity. The average water content of the bricks after setting is 17.4 %. This water content is completely dried out during testing. Pinewood, as all other wood types, shrinks when dried. The volumetric deformation parameter for pinewood is approx. 0.45 % [15] pr. percent change in the water content, so the volumetric deformation can be calculated from Equation 20. đ?‘‰2 = đ?‘‰1 ∗ (1 + 0.45% ∗ ∆đ?‘˘) Equation 20, [15]

This means that the volume of the fibres decrease by 7.8 %. This results in a thin perimeter pore around all the fibres, as shown in Figure 43.

Figure 43. Illustration of the moisture related fibre shrinkage. In between the wet and the dry diameter, a pore will appear when the brick is dried.

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The porosity from moisture related fibre shrinkage can be derived to 7.8 % * 3.7 % = 0.3 %.

8.2.7.1.4 Interfacial Transition Zone related porosity Around the aggregates, both fibres, sand and stones, a phenomenon occurs, Interfacial Transition Zone (ITZ-effect). Around a, relatively to the fibre, big aggregate particle, the cement particles’ edged surface hinder the particles from optimal packing. The ITZ-effect is shown in Figure 44.

Figure 44. Illustration of ITZ-effect. The cement particles (shaded black) closest to the aggregate surface are packed in lower concentration, than the other cement particles (grey shaded). The cavities between the cement particles are water filled.

During curing, the ITZ-effect results in less calciumsilicatehydrate-needles around the aggregate, causing a higher w/c- ratio in the ITZ-effect area, ultimately causing a higher porosity. Though the ITZ-effect is present with evidence, it is difficult to determine the impact on the porosity. The resulting porosity cannot be verified theoretically within this projects frame. Nevertheless, it remains a relevant factor when considering the relatively high porosity of the bricks.

8.2.7.1.5 Total open porosity In section 8.2.6, the open porosity is calculated to 36.0 %. By deducting the initial air content porosity (1 %), the chemical shrinkage and capillary water porosity (22.6 %), the cellulose fibre lumen porosity (2.8 %) and cellulose fibre shrinkage porosity (0.3 %), an estimation on the total ITZ-effect porosity can be estimated to 9.3 %, which seems reasonable.

8.2.7.2 Dry density Referring to the project objective, the dry density is of highest interest, as it gives an indication on the constructional load that workers, as well as the construction itself, must carry. The dry density is calculated to 1664 kg/m3. In Figure 45, it is compared with common building materials.

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Dry density comparisment 2500

Concrete,w/c 0,6

Cement mortar

Hard burned bricks

Lightweight concrete, constructions

500

Wood, pine

1000

CEMCEL Bricks

kg/m3

1500

Cellular concrete, medium density

2000

0 Dry density

Figure 45. Dry density of common building materials [4].

The dry density is lower than most constructional silicate and rock materials. In fact, only cellular concrete and light burned bricks have lower dry density. Considering Figure 38, an assumption can be made. The specimen P4-1 is cut from the end of the brick. This means that more of its surface is shaped by the formwork, packing the aggregates more closely than for specimen P4-2. This could be the reason why the dry density is higher for specimen P4-1 than for specimen P4-1. Likewise, this also corresponds with the slightly higher porosity of specimen P4-2. However the statistic foundation is insufficient to conclude on this.

8.2.7.3 Solid density The solid density is calculated to 2601 kg/m3. Not surprisingly, this is only a slightly less than that of the reference materials in Figure 46. With reference to section 6.3, the dry fibres have a very low bulk density before mixing, approximately 35 kg/m3. After mixing in the mortar, they almost instantly, reference appendix 7.1, obtain their fibre and lumen saturated outer surface dry density, Ď f.l.s.s.d, 1122 kg/m3, derived in section 6.4.5. Remembering that the cellulose fibres in the bricks constitute just two weight-%, the fibres presence therefore has low impact on the solid density. Solid density comparisment 2800 2600

Wood, pine

Cellular concrete, medium density

Concrete,w/c 0,6

1600

Cement mortar

1800

Hard burned bricks

2000

Lightweight concrete, constructions

2200

CEMCEL Bricks

kg/m3

2400

1400 Solid density

Figure 46. Solid density of common building materials [4]

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8.2.7.4 Surface dry saturated density The surface dry saturated density, ﾏ《.s.d. is calculated to 2022 kg/m3. The method for drying the surface, described in section 8.2.3, carries some inaccuracy. Nevertheless, the impact remains minor and the results therefore solid.

8.2.8 Sources of error During the testing phase 2, the specimens changed 0.2 weight-%. This could indicate minor out washing. However, it was detected that a few material particles fell from the specimen surface due to the handling while weighing etc. This is thought to explain the weight change. The vacuum never exceeded the vapour saturation pressure of water while the desiccator was water filled. It is therefore unlikely that the vacuum eroded the specimens by water boiling. After the testing, the possibility of the specimens having too large dimensions was considered. Normally, with conventional concrete, testing specimens for this experiment do not have larger dimensions than 15 mm to 20 mm. This is to secure that the core of the specimen will also be water saturated during the experiment. However, the pore structure in the CEMCEL Bricks is far larger than in conventional. Therefore the water can be assumed to have easier access to the specimen core. To remove all uncertainty, the testing was repeated with specimens of approx. 150 mm * 70 mm with a thickness of 10 mm. The results were a slightly smaller open porosity of 32 %, a dry density of 1763 kg/m3, a solid density is 2597 kg/m3 and a surface dry saturated density 2083 kg/m3. If the primary testing specimens were not water saturated in the core, the repeated testing should have resulted in a relatively larger open porosity. As this was not the case, this potential source of error is dismissed

8.2.9 Concise conclusion

The open porosity of the bricks is found to 36 % and the dry density is 1664 kg/m3. The appurtenant solid density is 2601 kg/m3 and the surface dry saturated density 2022 kg/m3.

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8.3 Capillary suction 8.3.1 Scope The scope of the experiment is to determine the CEMCEL Bricks capillary suction capability. The testing is performed in accordance with LBM- Prøvemetode 1, 6108/14.

8.3.2 Experimental setup and apparatus The specimens are cut from the brick as shown in Figure 47, having approximate dimensions 52 mm * 70 mm * 100 mm.

Figure 47. The two specimens used for the capillary suction testing, P4-3 and P4-4. The dashed lines indicate how the specimens were cut out of a brick.

The specimens are placed on distance pieces in a tray with distilled water, Figure 48. The distance pieces are pyramid shaped to secure optimal surface accessibility for the water. The water level reaches 3-5 mm up the sides of the specimens.

Figure 48. Experimental setup. Specimens are placed on distance pieces, reaching 3-5 mm up the sides of the specimens. The thermometers measure the temperature of the air and water. Later in the experiment, when intervals are >60 minutes, the tray is covered with a plastic sheet to prevent vaporation.

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8.3.3 Experimental procedure As in the porosity and density experiment, the cellulose fibres potential damaging when dried in an oven at 105 °C, requires the test performed in two phases, firstly preconditioned at 50 °C, secondly preconditioned at 105 °C. The testing procedure is the same for both. The phases are named as follows: 3. Phase 1 – Specimen P4-3 and P4-4, preconditioned at 50 °C 4. Phase 2 – Specimen P4-4 and P4-4, preconditioned at 105 °C After cutting, the specimens are placed in an oven, until the mass of the specimens is constant over three subsequent days. They are then placed in a desiccator with silica gel under atmospheric pressure until they have cooled. Then weighed, and the dry mass, m0, determined. The suction surface area, facing down into the water and the specimen height is measured with a vernier calliper. As soon as the specimens contact the water surface, a stop watch is started. Weight measurements are performed after 1 min., 2 min., 4 min., 8 min., 16 min., 32 min., 60 min., 120 min., 240 min. [mt] and subsequently till no more water is sucked by the specimens. Before weighing, the specimens are dried with a hard wrung cloth to obtain s.s.d.-state. During the weighing, the stop watched is paused, so that the time reflects the “inwaterâ€? time.

8.3.4 Capillary suction capability Capillary suction occurs due the surface stress of the water. This stress results in the water being sucked into the capillaries when the surface stress excesses the opposing forces, gravity and friction. The theory is parallel to that described in appendix 7.1.

8.3.4.1 Determination of the water absorption coefficient and the resistance coefficient The absorbed water quantity of the suction surface, Q [kg/m2], is determined for each interval based on Equation 21. đ?‘„=

đ?‘šđ?‘Ą − đ?‘š 0 đ??´

Equation 21

Where mt is the mass of the specimen at time t [s], m0 is the specimen’s dry-weight. A [m2] is the suction surface area. The absorbed water quantity, Q, is plotted as a function of time square rooted, t1/2, Figure 49.

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Figure 49. Illustration of capillary suction experiment. The sketch shows how Qkap and tkap1/2 is read on the graph. The upper limit is derived by adding a trend line for the two last measurement points. The lower limit is derived by adding a trend line for the intervals from 1 min. to 16 min.

The graph tangents in the beginning and ending condition are extruded till they intersect, Figure 49. The intersection is defined as the theoretical time, when the brick can no longer suck additional water. Based in this time, tkap, and the coherent water amount, Qkap, the water absorption coefficient, k [kg/(m2*s1/2)], can be calculated from Equation 22. đ?‘„đ?‘˜đ?‘Žđ?‘? đ?‘˜= đ?‘Ąđ?‘˜đ?‘Žđ?‘? Equation 22

A high k-value indicates a fast capillary suction. The capillary suction speed has importance when the material is exposed to rain, but also in relation to the subsequent drying. The resistance coefficient, m [s/m2], is also used to describe the capillary suction, or rather its resistance against it. It described the pores resistance preventing the capillary suction. It is found from Equation 23. đ?‘Ąđ?‘˜đ?‘Žđ?‘? đ?‘š= 2 đ?‘•

Equation 23

Where h [m] is the height of the specimen.

8.3.4.2 Calculation of the water absorption coefficient and the resistance coefficient The measurements are given in appendix 14, and plotted in Figure 50 for both phase 1 and phase 2 experiments.

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Capillary suction, 30,00

Q [kg/m2]

25,00

Phase 1, P4-3 Phase 1, P4-4

20,00

Phase 2, P4-3 Phase 2, P4-4

15,00

10,00

5,00

0,00 0

100

200

300

400

500

600

700

800

900

1000

t 1/2 [s1/2 ]

Figure 50. Capillary suction, phase 1 and 2. The figure shows the capillary suction for both specimens in both phases.

In the derivation for both phase 1 and phase 2, Qkap and tkap1/2 is found for each specimen, shown in appendix 14. Based on this, the water absorption coefficient, resistance coefficient and open porosity is calculated. Table 9 shows the result of the experiment, both for phase 1 and phase 2. 2

½

½ ½ tkap [s ] k [kg/(m *s )] m [10^6*s/m2] po Phase 1 25 277 0,090 7,64 0,26 Phase 2 13 165 0,079 2,70 0,19 Average 0,085 5,17 0,23 Table 9. Results of the capillary suction experiment for phase 1 and phase 2 and the overall average. 2

Q kap [kg/m ]

The water absorption coefficient is on average 0.085 kg/(m2*s1/2), but varies between 0.090 kg/(m2*s1/2) for phase 1 and 0.079 kg/(m2*s1/2) for phase 2. The average open porosity, po [%], is found to 23 %.

8.3.5 Discussion From looking at Figure 50, the ongoing slope indicates that the specimens in phase 2 had not reached mass equilibrium when the testing was stopped. Therefore phase 1 results must be used to derive the water absorption coefficient and resistance coefficient. However, the two graphs in Figure 50 demonstrate a pronounced difference in the progression of the capillary suction for the two phases. It can be assumed that phase 2, after sufficient time will reach the same level of absorbed water as phase 1. Remembering that phase 2 is dried at 105 °C, it should be expected that the phase 2 specimens had a higher absorption potential and therefore would absorb the water faster. However, the contrary is the case. The reason for this could be that the cellulose fibres collapse when dried at 105 °C. This would result in larger, but fewer pores in the bricks. Remembering the theory in appendix 7.1, the larger pores’ capillary suction occurs faster, but has smaller maximum suction height, why the absorbed water in the phase 2 specimens must

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“change pores� many more times (take detours so to speak) before it reaches the bricks’ top. In Figure 51, the absorption coefficient for the bricks is compared with that of common building materials and shows that the bricks absorb water slower than burned bricks, conventional concrete and cement mortar. Capillary number 0,350 0,300

Cement mortar

0,050

Burned bricks

0,100

Concrete

0,150

CEMCEL Bricks

0,200

Cellular concrete, medium density

k [kg/(m2*s½)]

0,250

0,000 Capillary number, k

Figure 51. Absorption coefficient, k, for common building materials [4].

To quantify the difference, a case study for comparing the bricks with burned bricks, k= 0.300 kg/(m2*s1/2), and conventional concrete, k = 0.155 kg/(m2*s1/2), is performed. Assuming that one square meter of untreated wall is exposed to severe driving rain (joints excluded) for 24 hours, the CEMCEL Bricks will absorb water as follows: đ?‘„đ?‘˜đ?‘Žđ?‘? = đ?‘˜ ∗ đ?‘Ą = 0.085

đ?‘˜đ?‘” đ?‘š2

∗đ?‘

1

2

∗ 86400 đ?‘ = 25.0 đ?‘˜đ?‘”/đ?‘š2

If the one square metre wall is build with the CEMCEL Bricks, it will consequently absorb 25 litres of water over 24 hours. The corresponding amounts for the wall build of burned bricks and conventional concrete is 88 litres and 45 litres respectively. In praxis, this indicates that the CEMCEL Bricks requires less surface treatment than the compared materials in order to prevent heavy water absorption.

8.3.6 Sources of error After each interval, the specimens were dried with a hard wrung cloth to obtain s.s.d.state. The results are sensitive to differences in the method used for the drying, differences in wringing level, differences in drying duration etc. These things were found to change the weight of the specimens with up to 2 grams. However, the square rooted time on the x-axis would reveal this by showing an angled curve. This was not observed. The evaporation of water from the tray and the specimens themselves was prevented by the plastic sheet. This also secured a stable water level, increasing the solidity of the results. The most significant source of error is the reading of Qkap and tkap1/2 from Figure 50. As described in appendix 14. If the intervals from 2 min. to 32 min. is used instead, the readouts will change to Qkap= 25.1 kg/m2 and tkap1/2 = 335 s1/2, Figure 52.

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Capillary suction, phase 1 30,00 Phase 1, P4-3

Q [kg/m2]

25,00 Phase 1, P4-4 20,00 Upper limit

15,00

Lower limit

10,00

Second lower limit

5,00

0,00 0

50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 t 1/2 [s1/2 ]

Figure 52. Derivation of Qkap and tkap1/2, when the lower limit interval is 2 min to 32 min, instead of 1 min to 16 min.

The resulting absorption coefficient, based on Equation 22, is 0.075 kg/(m2*s1/2), which is a decrease of 17 %. Referring to the previous case study, this would change the absorbed water for the CEMCEL brick over 24 hours from 25 litres to 22 litres. Based on this, the biggest potential source of error is considered to be reading errors. Nevertheless, the results are considered useful.

8.3.7 Concise conclusion Based on the experiment, the water absorption coefficient, k, is found to 0.090 kg/(m2*s1/2). The resistance coefficient, m, is found to 7.64 * 106 s/m2. Further, the CEMCEL Bricks are found to be superior to conventional concrete and burned bricks in terms of surface treatment necessity.

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8.4 Thermal conductivity 8.4.1 Scope The scope of the experiment is to determine the bricks thermal conductivity immediately after curing in wet conditions and in dry condition.

8.4.2 Experimental setup and apparatus The testing specimen, measuring approximately 300 mm * 300 mm * 73 mm, is placed in the testing setup, Figure 53. The experiment is performed in accordance with [16], and does not comply with CEN-norms, which require equipment not presently used at Technical University of Denmark. Cooling plate above specimen Heating plate below specimen Cold water basin Voltmeter Logger for logging measurements in ink. Power supply for heating plate

Figure 53. Photo of the complete experimental setup with cooling plate, heating plate, cold water basin, voltmeter, logger and power supply for the heating plate.

The testing setup, Figure 53, principled consists of a heating and a cooling plate. In between, the testing specimen is placed. This part of the setup is clarified in Figure 54.

Figure 54. Experimental setup around the specimen. The thermopiles are placed at point A and B [16]

The heating and cooling plate result in a one dimensional heat transfer, which gives a temperature difference between the two sides of the specimen. The one directional heat transfer is secured by wrapping the specimen in polystyrene and by the guard plate below the heating plate. Similar, a 1.5 mm thick layer is placed between the specimen and the heating and cooling plate. This also secures that specimen surface unevenness does not result in air cavities. When the temperatures are constant, the thermal conductivity can be calculated. The temperature difference is measured by a thermopile on both sides of the specimen, Figure 54 point A and B. The thermopile consists, on both sides, of five thermocouples between cobber and constantan. Page 69 of 106

All five thermocouples measure any temperature change, why the voltage output of the thermopile is magnified five times, increasing the sensitivity and accuracy of the setup. Measurements are shown in the voltmeter and logged in the logger with red ink, appendix 15. The thermopile, voltmeter and logging setup is shown in Figure 55.

Figure 55. Left: Thermopile. Centre: Voltmeter. Right: Logger

Measurements are in electric voltage, which is subsequently converted into temperature, remembering to divide results by five because of the voltage output magnification. For calculation purposes, a reference temperature is measured at point A with an electric thermometer. The cooling temperature is kept constant by cooled water coming from a cold water basin with constant temperature. The heating plates’ effect is regulated from the power supply, where the guard ring and guard plate balance also can be read. When voltage is put to the heating plate, the plate’s resistance will result in heat emergence. The resistance is known to 24.8 ohm, why the effect can be derived. The temperature regulating devices is shown in Figure 56.

Figure 56. Left: Cold water basin. Right: Power supply for heating plate

8.4.3 Experimental procedure The experiment is performed in two phases.  Phase 1, specimen unconditioned, right after curing at 32 °C and 100 % RH, i.e. in wet condition.  Phase 2, specimen conditioned at 50 °C until mass equilibrium. This is done to investigate how the moisture content influent on the thermal conductivity. Immediately after testing, the specimen is weighted. After phase 2, the specimen is dried in an oven at 105 °C. After drying, the specimen is weighted again in order to determine the water content in both phases and conclude its influent on the thermal conductivity. When all equipment is adjusted, the logger is reset and relevant testing data noted. After 1-2 days, equilibrium will occur. The equilibrium is maintained for 1-2 days, hereafter logging and other relevant data is noted.

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8.4.4 Determination Thermal conductivity describes how well a given material conducts heat. Generally, porous materials have a higher thermal conductivity than solid ones. This is due to the fact, that still air has a thermal conductivity of just 0.024 W/(m*K). If the pores on the other hand are water filled, the materials thermal conductivity is potentially increased, as waters thermal conductivity is 0.6 W/(m*K) [1]. To calculate the thermal conductivity, Equation 24 is used. P∗t P∗t Îť= = (A + ∆T) (0.0256m2 + ∆T) Equation 24

Where Îť [W/(m*K)] is the thermal conductivity, P [W] is the effect of the heating plate, t [m] is the height of the specimen, A [m2] is the one dimensional area and ΔT [K] is the temperature difference. P and ΔT are found from Equation 25 and Equation 26 respectively. đ?‘ˆ2 đ?‘ˆ2 đ?‘ƒ= = R 24.8Ί

Equation 25

Where U [V] is the voltage over the heating plate and R [Ί] is the resistance in the heating plate. Δđ?‘‡ = đ?‘˘ ∗ (25.9 − 0.06 ∗ đ?‘‡đ?‘š + 2.7 ∗ 104 ∗ đ?‘‡đ?‘š 2 − 106 ∗ đ?‘‡đ?‘š 3 )

Equation 26

Where u, [mV], is the voltage over the thermopile logged by the logger, divided by the number of thermocouples. Tm [K] is found from Equation 27. đ?‘˘ + 25.9 đ?‘‡đ?‘š = đ?‘‡đ?‘&#x;đ?‘’đ?‘“ + 2 Equation 27

Tref [K] is the reference temperature on the cold side.

8.4.5 Calculation The calculation results are shown in appendix 16, and summarised in Table 10. Calculations are performed in accordance with section 8.4.4. Specimen Drying conditions Average temperature in the specimen, [°C] Water content, u [%], after testing Thermal conductivity [W/mK]

P3-1* Fresh 12,9 19,1% 0,56

P3-2* Fresh 12,7 19,1% 0,57

P3-3 Fresh 17,9 19,1% 0,71

P3-4 Fresh 19,7 19,1% 0,77

P3-5 50°C 19,1 1,8% 0,43

Table 10. Results of the thermal conductivity experiment. Drying conditions describe whether the specimen were tested straight after curing or dried in an oven at 50°C for three days beforehand. The water content describes which water content the CEMCEL brick had right after testing. * indicates results that were discarded.

8.4.6 Discussion The thermal conductivity is found between 0.43 W/ (m*K) and 0.71 W/ (m*K), Table 10. The average thermal conductivity is 0.61 W/(m*K) and the standard deviation is 0.14 W/(m*K). During P3-1 and P3-2 testing, the cooling side was 9.0 °C - 10.0 °C. Because of the high water content and the high temperature difference, a moisture transfer from the heated side of the specimen towards the cooled side occurred. As a consequence, the situation did not reach equilibrium state, which was revealed by the power supply, indicating an unbalance between the guard plate and guard ring. In order to try and reach equilibrium state, the cooling plates' temperature was increased to 15,9 °C in testing P3-3 and P3-4. In testing P3-4, the heating plate effect was doubled to Page 71 of 106

39.2W/m2, to reduce the risk of condensation. For both testing P3-3 and P3-4 the equilibrium state was reached, indicating result solidity. In the following, the average thermal conductivity of testing P3-3 and P3-4, 0.74 W/(m*K), is therefore used as representative for the freshly set CEMCEL Brick. The standard deviation between P33 and P3-4 is low, 0.05 W/(m*K). The dried testing, P3-5, has a water content of u = 1.8 %, whereas the others has u = 19.1 %. Remembering the relatively high thermal conductivity of water, 0.6 W/(m*K), it is therefore not surprising that testing P3-5 has lower thermal conductivity, 0.43 W/(m*K). Thermal conductivity comparisment 1,2 1,1 1 0,9

Concrete, ρ=2200

0,1

CEMCEL bricks, freshly cured

0,2

Cement mortar

0,3

Lightweight concrete, constructions

0,4

Massive bricks

0,5

CEMCEL bricks, dried at 50°C

0,6

Wood, pine, radial direction

0,7

Cellular concrete, medium density

w/(m*K)

0,8

0 Theoretical thermal conductivity

Figure 57. Thermal conductivity of the fresh and dried CEMCEL Brick and common reference building materials[4]. All reference values are theoretical for dry conditions.

Figure 57 compares the CEMCEL Brick with reference materials. All the reference values are for dried condition, why they should only be compared directly with the dried CEMCEL Brick condition, the light green column in Figure 57. In another project [17], the thermal conductivity of a commercial cellular concrete, Celblok from H+H Celcon, was measured on the same equipment. The Celblok had a thermal conductivity of 0.46 W/(m*K). With a thermal conductivity of 0.43 W/(m*K), the CEMCEL Bricks are superior, though the Celblok had a porosity of 83 %.

8.4.6.1 Correlation between thermal conductivity for ordinary concrete and the CEMCEL Bricks The CEMCEL Bricks should theoretically be placed in between the pine wood and the concrete in Figure 57. This is also the case. What seems surprising is that though the cellulose fibre vol-% is just 3.7 %, and the remaining 96.3 % is basically air and concrete, the thermal conductivity of the CEMCEL Brick is far superior to concrete. In fact, it is slightly better than massive burned bricks and significantly better than constructional lightweight concrete. This interesting matter can be explained by investigating the theory of thermal conductivity for two-phased porous materials [4], using either the parallel model or the series model, Equation 28. λ1 λ2 v1 λ1 + v2 λ2 ≥ λ ≥= v1 λ2 + v2 λ1

Equation 28

However the equation in Equation 28 only applies for homogeneous-layered materials, anisotropic materials. Since the heterogeneous CEMCEL Brick is isotropic, the results can be narrowed by using Equation 29. 2λ2 + v1 (λ1 − λ2 ) λ1 + λ2 + v1 (λ1 − λ2 ) λ1 ≥ λ ≥ λ2 2λ1 − v1 (λ1 − λ2 ) λ1 + λ2 − v1 (λ1 − λ2 ) Page 72 of 106

Equation 29

These equations estimate the lower and the upper limit for the thermal conductivity. The CEMCEL Brick can be simplified to the following two phases by neglecting the cell walls in cellulose fibres.  Phase 1: Concrete consisting of sand/stones, gel water and gel solid with w/cratio =1 and a combined theoretical thermal conductivity, λc = 0.75 W/(m*K) [4]  Phase 2: Pores containing either water with theoretical λw = 0.6 W/(m*K) or air with λa = 0.024 W/(m*K). The pores volume percentage is derived in section 8.2.7.1 to Vp = 36.0 %. The concrete volume, Vc, consists of sand/stones, gel water and gel solids, the remaining 74 %. The results using the parallel and series model are given in Table 11. Fresh brick 50°C dried brick 0,74 0,43

Experimental results Anisotropic, upper limit Anisotropic, lower limit

0,77 0,63

0,56 0,06

Isotropic, upper limit 0,71 0,46 Isotropic, lower limit 0,71 0,14 Table 11. Thermal conduction value based on the parallel and series model for anisotropic materials. Thermal conductivity based on the isotropic model.

The actual thermal conductivity is closest to the isotropic model both for the freshly cured brick and the 50 °C dried brick. Table 11 also shows that the upper limit is most suited. This consists with the theory, as the upper limit is used for porous materials with low thermal conductivity particles in a high thermal conductivity solid material, whereas the series model is the opposite.

8.4.6.2 Water content and temperature’s influence on the thermal conductivity The water content has impact on the thermal conductivity because of the high difference between waters and airs thermal conductivity. The relation is shown in Figure 58, for the CEMCEL Brick. Thermal conductivity dependency on the water content 0,8

W/(m*K)

0,7 0,6 0,5 0,4 0,3 0,00

0,05

0,10

0,15

0,20

Water content, u

Figure 58. The thermal conductivity’s dependency on the water content.

Also the temperature has impact, both directly and indirectly. Directly, materials thermal conductivity usually depends on the temperature. With higher temperature, the thermal conductivity increases. Indirectly, the temperature inflicts on other heat Page 73 of 106

transferring mechanisms like radiation and convection. However these contributions to the total heat transportation are small and will not be assessed.

8.4.7 Sources of error The experiment is associated with a number of potential sources of error both in the experimental setup and readouts. A primary source of error is the risk of air between the specimen and the heating/cooling plates. As described in section 8.4.2, polystyrene foam was put in between to even out the surface. The surrounding temperature varies through the day, which inflicts on the readouts. The variation is relatively low, why this source of error is considered minor. The thermal conductivity depends on the specimen thickness. Thus, a misreading of the thickness by 0.5 mm will result in an error in the thermal conductivity by 0.7 %. However the thickness was measured with a very accurate digital vernier calliper, why this source of error is considered minimal. Also, as described in section 8.4.6, the moisture content is a potential source of error. Finally, the dry density was found in the experiment to 1607 kg/m3. This differs from that found in section 8.2.7.2 by 3.4 %.

8.4.8 Concise conclusion Based on the experiments, the thermal conductivity of the fresh brick with a water content of 19.1 % is 0.74 W/(m*K). When dried at 50 째C until a moisture content of 1.8 %, the thermal conductivity is 0.43 W/(m*K). This indicates a clear connection between the water content and the thermal conductivity.

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8.5 Moisture related deformation and hysteresis 8.5.1 Purpose The purpose of the experiment is to determine the moisture related shrinkage and swelling of the CEMCEL Brick as a consequence of changes in the relative humidity, RH [%], under constant temperature. The experiment will be performed at relative humidity in the interval between 100 % and 50 %, both using desorption and absorption in order to reveal a potential hysteresis effect. Between intervals, reference specimens are weighted to construct the experiments specific sorption isotherm.

8.5.2 Experimental setup and apparatus The experimental setup will be briefly described in the following. A thorough description and explanation is given in [17]. The system consists of three overall components, Figure 59, namely:  Climate chamber SKANFRYS  LVDT- displacement gauges (Linear Variable Differential Transformer)  Computer with the software, SKANFRYS(Main), installed.

Figure 59. Left, the overall setup. Centre, the testing specimens fixed in the steel rack with the LVDT’s fixed, showing the wiring to the computer. Right, the computer showing the user interface of software, SKANFRYS (Main).

The SKANFRYS climate chamber maintains a constant relative humidity and temperature based on the user input. The field of application is relative humidity between 10 % and 95 % and between 10 °C and 60 °C for the temperature. Humidity is regulated by a Condair moisturizer in the top of the chamber and the temperature by a heater and a compressor if necessary. A Novasina moisture - and temperature gauge measures the climate. Two HBO-regulators regulated remaining components of the climate chamber. Windings in the LVDT’s house registers movement of the core, which moves frictionless in the house, Figure 60.

Figure 60. Left, Winding diagram for the LVDT’s. Centre, the LVDT-core separated from the house, Right, the LVDT assembled as used in the experiment.

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A small nut is glued centrally to the specimens end. The thread of the LVDT’s core is screwed onto this, securing a solid fixing. A brass-disk is glued to the other end of the specimen, securing a stable stance. The specimens and the LVDT’s are fixed in a frame, securing a stable platform for the experiment. The frame is made of steel, and therefore moisture unaffected, Figure 61.

Figure 61. Left, specimens fixed in the frame. Centre, close-up of the LVDT’s connection to the specimens. Right, DIN-sockets, receiving data from the LVDT’s.

The data transfer happens through DIN-sockets inside the climate chamber to the computer, from where the climate input is controlled. The data output is converted to a text file that can be imported directly to Microsoft Excel. The specimens has the approximate dimensions, 10 mm * 70 mm * 150 mm. The slim geometry is chosen because it reduces the time before the specimens reach state of equilibrium between the RH-intervals. On the other hand, the specimens could practically not be cut any thinner because they would then break in the cutting process.

8.5.3 Experimental procedure Prior to testing commencement, the setup is calibrated, and a sensitivity analysis is performed for the LVDT’s. This is done in the SKANFRYS(Main) software interface.

8.5.3.1 Preparation of the specimens Three specimens are wet-cut to maintain their moisture content. All specimens are cut from the centre of the brick to secure, that potential special circumstance for the bricks’ surface does not influence on the results. The nut and brass disk is glued onto the specimens using X60 glue, two-component glue suitable for gluing porous, moist materials. Apart from the testing specimens, reference specimens are also prepared. These are small pieces that can be taken out of the climate chamber without interrupting the testing setup. These are used to determine the water content. The system is turned on to warm up some time before testing commencement at the conditions for the first interval.

8.5.3.2 Measurements Through the experiment, the temperature was set to 32 °C. The deformation measurements are performed at the following humidity intervals:  Desorption from “Fresh brick”- RH – 85 % RH  Desorption from 85 % RH – 50 % RH  Absorption from 50 % RH – 85 % RH

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The software is set to log the data every 15 mins. Every interval is maintained until the specimens deformation is in equilibrium. At each equilibrium state, the reference specimens are weighted to determine the water content.

8.5.4 Determination Moisture related deformation is defined as changes in the materials dimensions as a direct consequence of changes in the water content. In section 8.5.3.2 it is mentioned that each interval is maintained until the specimens deformation is in equilibrium. However, this can in praxis [18] take several months or even years. Therefore each interval is maintained until the deformation increase is considered very small.

8.5.4.1.1 Sorption isotherm The sorption isotherm for the experiment is shown in Figure 62. Measurements are shown in appendix 17. The hysteresis effect can be detected as the difference between the two equilibrium points at 85 % RH. The hysteresis effect is likely to be a consequence of water being trapped into micro pores during desorption [4]. Sorption isotherm 15,15%

16,00%

Water content [%]

14,00% 12,00% 10,00% 8,00% 6,00%

2,99%

4,00%

2,00%

1,13%

0,00%

1,13%

40,00%

2,74% 50,00%

60,00%

70,00%

80,00%

90,00%

100,00%

Relative humidity [%] Desorption

Adsorption

Figure 62. Sorption isotherm for the moisture related deformation. Because the specimens have not necessarily reached equilibrium in all intervals, the sorption isotherm is not representative for the CEMCEL Brick in general, but only for the specific deformations in the experiment.

8.5.4.1.2 Moisture related deformation The moisture related deformation for the three specimens is shown in Figure 63. All the tested specimens were cut from the middle of the bricks to make sure that the properties were as homogenous as possible. This is confirmed in Figure 63, where the three curves are relatively close to convergent. Therefore, the results will be presented as the average of the three specimens in the following. The average curve and graphical analysis for the experiment is given in appendix 18.

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Moisture related deformation 0,02

100

90

0

100

200

300

400

500

600

700

800

900

1.000 80

70

Deformation [%]

-0,02 60

-0,04

50

40 -0,06 30

20

Temperature [째C] and relative humidity [%]

0

LVDT2(V)

LVDT3(V) LVDT4(V)

Temp RH

-0,08

10

-0,1

Time [hours]

0

Figure 63. Deformation curves for the three specimens, and the climate inside the chamber. The deformation in percentages is read on the left vertical axis. The temperature and relative humidity is read on the right vertical axis. The curves indicate some measuring noise, especially below the lines. However the curve lines can easily be detected and the noise therefore ignored.

From appendix 18, the equilibrium states at 85 % RH can be used directly to derive the hysteresis effects consequences for the deformation. The difference in the equilibrium water content at 85 % RH can be read from Figure 62 to 0.27 %. This results in hysteresis caused deformation difference of less than 0.01 %, indicated by a yellow arrow in appendix 18. Consequently, there is a difference between swelling and shrinkage in the CEMCEL Brick. This difference is believed to be the result of hysteresis effect. In a formerly performed diploma project [18], the hysteresis caused deformation difference for cellular concrete in the interval from 50 % RH to 80 % RH, was found to 0.05 %. This indicates that the CELCEM Bricks has relatively low hysteresis sensitivity in terms of deformation. The maximum registered deformation, from fresh condition to 50 % RH, can be derived to 0.075 %, indicated by a light blue arrow in appendix 18.

8.5.5 Discussion The CEMCEL Bricks moisture related deformation is compared with reference materials in Figure 64. This that the CEMCEL Brick deforms more than most materials as a consequence of changes in humidity. The reason lies in the paper fibres. Pine wood swells up to 0.45 % in the tangential direction. Loose cellulose fibres swells even more. And because the fibres are mixed in the bricks in random orientations, this pushes the deformation further than if paper fibres had not been added.

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Moisture related deformation comparison 0,9 0,8

0,1

Cement mortar

0,2

Paper based brick

0,3

Concrete

0,4

Lightweight concrete, constructions

0,5

Cellular concrete, medium density

0,6

Hard burned bricks

Shrinkage [0/00]

0,7

0 Completely wet - 50 % RH

Figure 64. Moisture related deformation of the CEMCEL Brick and common reference building materials[4]. All reference values are for drying from completely wet to 50 % RH.

In order to fully understand the potential consequences of this swelling, and the necessary initiatives, a worst case is addressed. A reference slum dwelling, having a gross area of 4 m * 5 m is considered. The outer wall, 5 meters long, is build immediately after the curing has ended, so the bricks have fresh condition. In the following season, the climate stays at 32 째C and 50 % RH for a sufficient period for the bricks to obtain equilibrium. This results in a swelling of 0.075 % * 5000 mm = 3.75 mm. This deformation is sufficient to result in substantial tension related cracks. Assuming that the inside climate conditions at the given worst case is more moist, than the outside conditions, the consequences is intensified. The climate variations from the inside to the outside will result in corresponding deformation variations and subsequently tensile stress variations through the wall, illustrated in Figure 65.

Figure 65. Sketch of stress variations through the wall thickness due to different inside and outside climate conditions.

For a series of individual bricks, like the 5 meter wall in the slum dwelling, this effect could result in system deformations, illustrated in Figure 66. This could lead to further cracking, especially around wall openings like doors and windows. Also, if the dwelling foundation is insufficient, it could result in transverse deformation. However, any conclusions on the extent of the described potential problems require further investigation. Page 79 of 106

Figure 66. System deformations for a series of bricks

8.5.6 Sources of error In the measurements, a number of the points vary from the overall tendency. This is believed to be a system error, potentially caused by the high age of some of the electronic components. However the overall tendency is clear in the experiment for all specimens. From appendix 18, the climate can be seen to vary slightly around the set-points. For the temperature, +/- 0.5 째C and for the humidity, +/- 2.5 % RH. These variations have probably increased the standard deviation slightly.

8.5.7 Concise conclusion Based on the experiment, the shrinkage at desorption from fresh condition to 50 % RH at 32 째C is 0.075 %. A hysteresis effect is identified and quantified to less than 0.01 % at desorption and absorption to equilibrium at 85 % RH at 32 째C. To prevent tensile stress and adherent cracking, the bricks should be dried in the sun prior to building. This should be easy in the Indian climate. If the bricks are dried more than the equilibrium state they will obtain after being built in, it will result in pre-compression after building. This is considered advisable, as it will prevent the brick from being exposed to tensile stresses in dry seasons.

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8.6 Compression strength and stress/strain-relation curve 8.6.1 Scope The primary scope of the experiment is to determine the compression strength and stress/strain- relation curve for the fresh CEMCEL bricks immediately after curing. The secondary scope is to compare the compression strength of the CEMCEL when using chemically pulped paper fibres rather than the mechanically pulped paper fibres from Papiruld ApS. The tertiary scope is to perform a sensitivity analysis on the compression strengths dependency on the w/c-ratio. For conventional concrete, the compression strength can be tested using standard DS 423.23. However pretesting indicated that the bricks compression strength was approximately 3.5 MPa, which is around 10 % of that of conventional concrete [4]. Therefore this testing method was unsuitable. For determining the stress/strain- relation curve however, no official standard exists, appendix 19. Eventually, a testing method was therefore designed for the project in collaboration with Docent Peter Goltermann, appendix 19. This method uses elements from the testing procedure in CEN/TC 177, which is designed for Determination of the compressive strength of autoclaved aerated concrete. The compression strength of aerated concrete is 1 MPa - 6 MPa, based on the density. Therefore the CEN/TC 177 testing procedure suits the experiment. The testing method is explained in the following.

8.6.2 Experimental setup and apparatus The experiment was performed using the following specimen specifications. The formula for the primary and secondary specimens is that of the CEMCEL Brick. The formula for the tertiary specimens is given in appendix 20. w/c- ratio Number of specimens Primary testing Mechanically pulped Secondary testing Chemically pulped Tertiary testing #1 #2 #3 #4

1,0

4

1,0

4

1,1 1,2 1,3 1,4

4 2* 4 4

Table 12. Specimen specifications. * After two days of curing, the specimens were tested taken directly out of the form. However they had not cured sufficiently and two of the specimens broke. The rest was kept in the forms until they had cured sufficiently.

Apart from the changes in the w/c-ratio, and the appurtenant changes in cement paste/aggregate-ratio, the production method is sought as uniform as possible to ensure a good comparison basis. In the tertiary testing only w/c-ratios higher than that of the primary testing are addressed. With reference to section 3.3.2.2, this is because higher cement contents than that of w/c-ratio 1.0 are economically unsustainable as the cement content must be kept less than 290 kg/m3. Page 81 of 106

The top and bottom of the specimens are in the forming process scraped to have the most levelled surface possible. The specimens were cured and conditioned as freshly cured at 100 % RH and 32 °C. This is representative to the Indian reference conditions. Further, the bricks can be presumed to gain strength over time from drying and further hydration, making the freshly cured condition a “lowestâ€? case for the bricks compression strength. The testing is performed using an Instron 6025 compression testing machine, Figure 67. Below the testing specimen, a plastic sheet is laid out to catch brick fragments, which is used to determine the water content.

Figure 67. Left, Instron 6025 hydraulic compression testing machine. Right, the computer where the specimen details are inserted and the results are logged.

The testing results are converted to a text file, which can be imported into Microsoft Excel.

8.6.3 Experimental procedure Before the testing begins the testing specimens’ precise diameter and height are typed into the computer user interface. Based on this the software can calculate the stress and strain and give this as output with the coherent deformation. Before the testing can begin, the load setup for the Instron 6025 is derived.

8.6.3.1 Load setup of the Instron 6025 The Instron 6025 can run both compression and deformation controlled. Because the CEMCEL Bricks are newly developed, the properties are unknown. A basic pretesting of the bricks compression strength, fc [MPa] was performed with fc = 3.7 MPa or 29 kN, but the appurtenant strain in the pretesting remained unknown. To effectively control the testing time to be around 1 minute, the load setup pr. time unit was therefore chosen compression controlled as follows: 0.05đ?‘€đ?‘ƒđ?‘Ž 0.05đ?‘ 392.7đ?‘ = ∗đ??´ = = 23.6đ?‘˜đ?‘ /đ?‘šđ?‘–đ?‘› 1đ?‘ 1đ?‘ 1đ?‘ Where A is the approximate area of the specimens compressed surfaces, 7.9*103 mm2.

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8.6.3.2 Loading procedure The testing specimen is placed in Instron 6025 with a piece of ordinary printing paper between the specimen and Instron on both sides. The paper has two purposes, firstly it will reveal uneven loading by observing the post failure “footprint� of the specimen in the paper. The second purpose is explained in the following. The loading procedure is defined and explained afterwards. The numbers refers to the numbers in Figure 68. 1. Load until fc25% = 25 %* 3.7 MPa ≈1.0 MPa or 8 kN. This removes instrumental tolerances and specimen surface tolerances, and compresses the paper. 2. Unload to 0.3 MPa or 2.5 kN. At this point, the paper remains compressed, and the instrumental tolerances remains removed. At this point, the strain is balanced to zero in the user interface, which moves the graph left till it intersects the y-axis at 0.3 MPa. The starting point on the stress/strain relation is now effectively set to 0.3 MPa stress and zero strain. 3. Reset the strain-axis to zero to move the graph. 4. Load to failure with 0.05MPa/s, according to CEN/TC 177.

Figure 68. Illustration explaining the loading procedure. The dotted line indicates the curve if the point 1. to point 2. load circle is not performed.

After the specimen fails, fragments are weighed, dried and weighted again to determine the water content.

8.6.4 Primary testing - Determination of compression strength and stress/strain relation The result for the individual four specimens in the primary testing is given in appendix 21. The maximum detected compression strength is fc= 3.82 MPa. The average for the four specimens is 3.74 MPa. The testing specimens for the primary testing had an average water content of 10.3 % during the testing. In Figure 69, the results are graphed relative to this maximum detected compression strength, 3.7 MPa.

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Stress/Strain

Index stress [-] 1,2

P1-1 P1-3

1

P1-4 P1-1

0,8

P1-2 P1-3

0,6

P1-4

0,4 0,2 0 0

1

2

3

4

5

6

7

8

9

10

Strain [0/00]

Figure 69. Stress/strain relation and compression strength for the primary testing the CEMCEL Bricks. Index 1 = 3.7 MPa.

The four graphs are convergent within a 5 % deviation, which indicates uniformity between the specimens. In Figure 70 and Figure 71, reference stress/strain relations for ordinary concrete and Lightweight Aggregate Concrete are given, indicating similar curve profiles between these and the CEMCEL Bricks.

Figure 70. Reference stress/strain relation for ordinary concrete [20].

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Figure 71. Reference stress/strain relation for Lightweight Aggregate Concrete [20].

Since the testing procedure did not include load-unload cycles, as required in E-modulus testing standards, E-modulus and elastic/plastic areas of the graphs in Figure 69 cannot be determined with any certainty. However, a qualified guess could indicate a linear elastic phase from 0 % to 30 % of fc, Figure 72. This linearity has different slopes between the individual specimens, and an extraction of Young’s modulus therefore complicated. An estimate using Hooke’s law, indicated by a dashed line in Figure 72, gives an E-modulus of 1280 MPa. Stress/Strain

Index stress [-]

0,9 P1-1

0,8

P1-2 P1-3

0,7

P1-4

0,6 0,5 0,4 0,3 0,2 0,1 0

0

1

2

3

4 Strain [0/00]

Figure 72. Close up of the first part of the stress/strain relation from Figure 69. Dashed black line is the estimated elastic E-module. Solid black line is the expected plastic linear phase.

After 30 % of fc, the graphs break, followed by a linear plastic phase from 30 % to 70 % of fc. This phase is expected to be plastic, though it seems linear. Therefore an Emodule should not be extracted for this phase.

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8.6.4.1 Crushing pattern and homogeneity analysis In Figure 73, a representative CEMCEL Bricks specimen after crushing is shown.

Figure 73. CEMCEL Bricks specimen after crushing.

The testing specimens all broke in shear breaks or cone shaped shear breaks. The breaking pattern follows that on conventional concrete. The principle of shear breaks or cone shaped shear breaks is Figure 74.

Figure 74. The principle of shear breaks (left) or cone shaped shear breaks (right) for conventional concrete.

One of the specimens was cut through to analyze the homogeneity level. The revealed surfaces are shown in Figure 75. It indicates that the different aggregates are evenly distributes through the section.

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Figure 75. CEMCEL Brick cut trough of primary specimen for homogeneity analysis.

8.6.5 Secondary testing - Comparison of compression strength and stress/strain relation for chemically pulped paper fibres The result for the individual specimens in the secondary testing is given in appendix 22. In Figure 76, the results are graphed relative to this maximum detected compression strength in the primary testing, fc= 3.82 MPa. The testing specimens for the secondary testing had an average water content of 17.3 % during the testing.

Stress/Strain

Index stress [-] 1,2

P1, w/c=1,0

1 S1, w/c=1,0

0,8 0,6 0,4 0,2

0 0

1

2

3

4

5

6

7

8

9

10

Strain [0/00]

Figure 76. Comparison of the compression strength and stress/strain relation when using chemically pulped paper fibres rather than the mechanically pulped paper fibres from Papiruld ApS. P1 is the best performing of the primary testing specimens. S1 is the best performing of the secondary testing. Index 1 = 3.7 MPa.

Based on the testing the chemically prepared pulp reduces the compression strength to approximately 80 % of the compression strength of the primary testing. It seems that the graphs are convergent in the first linear phase. Afterwards, they develop similar, but with different slopes. Page 87 of 106

8.6.6 Tertiary testing - Sensitivity analysis on the compression strengths dependency on the w/c- ratio The result for the individual specimens in the tertiary testing is given in appendix 22. In Figure 77, the results are graphed relative to this maximum detected compression strength in the primary testing, fc= 3.82 MPa. The testing specimens for the tertiary testing had an average water content of 17.3 % during the testing.

Stress/Strain

Index stress [-] 1,2

P1, w/c=1,0

1

S1, w/c=1,0 S3, w/c = 1,1

0,8

S3, w/c = 1,2

0,6 S3, w/c = 1,3

0,4

S3, w/c = 1,4

0,2

0 0

2

4

6

8

10 Strain [0/00]

Figure 77. Result from primary, secondary and tertiary testing. P1 is the best performing of the primary testing specimens, having w/c=1.0. S1 is the best performing of the secondary testing. S3 is the best performing of the tertiary testing at different w/c-ratios. Index 1 = 3.7 MPa.

Based on the testing, the compression strength is reduced to 68% at w/c=1.1, 62% at w/c=1.2 and 58 % at w/c=1.3 and w/c=1.4. Still it seems that the graphs are convergent in the first linear phase. The relations between the compression strength and the w/c-ratio are graphically shown in Figure 78. Relative Compression strength dependency on compression w/c- ratio strength [%] 100%

90%

80%

70%

60%

50% 1

1,05

1,1

1,15

1,2

1,25

1,3

1,35

1,4

w/c- ratio [-]

Figure 78. Relation between compression strength and w/c-ratio.

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8.6.7 Discussion Figure 78 shows that the compression strength is depending on the w/c-ratio. However it should be remembered that the first point (w/c = 1.0) was from the primary testing and the remaining from the tertiary testing. The primary testing specimens had an average water content of 10.3 %. The tertiary testing specimens had a water content of 17.3 %. This could be the explanation why the first section of the graph (from w/c = 1.0 to w/c = 1.1). This indicates that the compression strength increases when the bricks are dried. This indication is in correlation with theoretical expectations. In Figure 79, the compression strength is compared with common reference materials. Conventional concrete and brick have much higher compression strength, whereas cellular concrete has lower strength than the CEMCEL Brick. Compression strength 35 30

Cellular concrete, medium density

Paper based brick

5

Wood, pine, tangential, u=12%

10

Cement mortar

15

Light burned bricks

20

Concrete,w/c 0,6

[MPa]

25

0

Figure 79. Compression strength of the CEMCEL Brick and common reference building materials [4].

8.6.8 Sources of error The Instron 6025 is a very precise equipment. Therefore errors in the measurements are unlikely. A possible source of error is if the specimens were not homogeny. Only one specimen was cut through to observe homogeneity. The top and bottom of the specimens also represent a potential source of error. If these are not perfectly plain, it will result is unequal stress over the surfaces during compression.

8.6.9 Concise conclusion The maximum compression for the freshly cured CEMCEL Brick is found to 3.82 MPa, and the testing average to 3.74 MPa. The E- module is found to 1280 MPa. The CEMCEL Brick crushes in a sliding pattern similar to that of conventional concrete. The CEMCEL Brick is homogeneous. Using chemically pulped paper fibres reduces the compression with 20 % to 3.1 MPa. The compression strength is reversed dependent on the w/c- ratio. At w/c= 1.4, the compression strength is reduced with 42 % to 2.2 MPa. The water content of the CEMCEL Bricks is expected to have impact on the compression strength. When dried, the CEMCEL Bricks’ compression strength increases.

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8.7 Investigation of biological deterioration 8.7.1 Scope The scope of the experiment was to determine how a brick containing organic cellulose fibres would react to exposure to water over a period of 3 months. The specimens used were produced early in the project phase. They contain approximately 50 % cellulose fibres. Hence, they are not representative to the CEMCEL Brick developed in the project. Instead they function as a worst case reference, because the amount of biological matter is far greater than in the CEMCEL Bricks.

8.7.2 Experimental setup and procedure Two identical specimens were placed in a plastic tray filled with 20 mm water. The specimens were placed in an office, and in a climate chamber under the following conditions:  Office, condition 1: Temperature, 22 °C, and humidity, 39 % RH  Climate chamber, condition 2: Temperature, 32 °C, and humidity, 35 % RH The specimens were left untouched, unless when additional water was filled in the tray. The setup for condition is shown in Figure 80.

Figure 80. Experimental setup for condition 1. The setup for condition 2 is identical, except from the climate.

8.7.3 Determination and discussion After the experiment, the two specimens were visually compared, Figure 81.

Figure 81. Left, condition 1 and condition 2 compared. The red dots indicate where visually detectable fungus spores were located. Right, close-ups of some of the fungus spores developed on the specimens.

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The experiment clearly show that the specimen 1 tested in an office with 22 째C and 39 % RH develop far more severe levels of fungus all over the brick. At first hand this seems surprising, as the humidity is almost the same for both conditions and the temperature for both condition 1 and condition 2 is under the lethal temperature for most common fungus species, Figure 82.

Figure 82. Temperature and water content growth conditions for common funguses known in the Danish building industry.

Theoretically, the higher temperature in condition 2 should allow higher water content [4] and hence make the fungus risk bigger. However, is seems that the absorbed water vaporises from the specimen in condition 2. This was confirmed by physically touching the specimens. The condition 1 specimen was surface wet, whereas the condition 2 specimen felt completely dry, expect from right over the water level.

8.7.4 Concise conclusion The experiment cannot be used to make any general conclusions on biological deterioration for the CEMCEL Brick. However, the CEMCEL Brick apparently performs better in warmer conditions as long as the water evaporation is not prevented by heavy surface treatment etc.

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8.8 Analysis of microstructure and elemental composition 8.8.1 Scope The micro geometry of the paper fibres delivered from Papiruld Danmark ApS is investigated using a Nikon SMZ-2T optical microscope with a Nikon DN100 digital net camera attached. Then the microstructure of the CEMCEL Brick is visually determined. A Quanta 200 Scanning Electron Microscope (SEM) is used. Further, the elemental composition of the CEMCEL Brick is analysed, using Energy Dispersive X-ray Spectroscopy (EDX).

8.8.2 Experimental setup and procedure The experimental setup and procedure is described in Annex 1. The annex also describes how to evaluate the readouts more thorough. Both the SEM analysis and the EDX analysis were performed twice at different parts of the specimen to broaden the statistic basis of the experiment. The specimens were broken from the brick with a pincers.

8.8.3 Microscopic analysis on geometry the paper fibres delivered from Papiruld Danmark ApS Before investigating the mechanically pulped paper fibres from Papiruld Danmark ApS, the origin of the fibres, a newspaper using recycled paper is looked upon. Figure 83. In the picture, the individual fibres can surprisingly easily be distinguished from one another. In Figure 84, similar paper is mechanically pulped at Papiruld Danmark ApS.

Figure 83. 50 times magnification. Photo of recycled paper from the newspaper Ingeniøren. Paper is not pulped.

Figure 84. 50 times magnification. Photo of paper pulp using paper fibres delivered from Papiruld Danmark ApS.

To investigate the difference between mechanical and chemical pulping, a sample of chemical paper pulp was produced. This was done by mixing a newspaper with water. Over time and using stirring, the newspaper dissolved into loose fibres. A small pack of these and the mechanically pulped fibres was photographed. The results are shown in Figure 85.

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Figure 85. 50 times magnification. Small pack of pulped paper fibres. Left, mechanically pulped. Right, chemically pulped.

It seems that the mechanically pulped fibres contain more impurities, probably from the cutting process. Micro fibrils seem to be coming from the surface of the individual mechanically pulped fibres, probably from being roughened in the pulping process. To investigate this more thorough an individual fibre from both packs was separated and photographed, Figure 86. This confirmed the observation. The figure also shows that there is a large difference in the fibre length. This is a natural cause of the cutting process in the mechanical pulping process. The general dimensions of paper fibres cannot be determined based on the analysis. However, the dimension used in the project experiments, 3.5 mm length and a diameter of 30 Âľm, can be assumed plausible. Also, these dimensions are supported by literature based on thorough experiments [11].

Figure 86. 50 times magnification. Single pulped paper fibre. Left, mechanically pulped. Right, chemically pulped.

8.8.4 Scanning Electron Microscope analysis on CEMCEL Bricks The first photo that was investigated, Figure 87, shows the surface that was revealed when the CEMCEL Brick was cut with a pincers at 50 times magnification. Fibres and sand grains are easily identified and seem to be mixed well. The picture also shows shaded areas that are internal pores which have been cut open by the pincers.

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Figure 87. SEM photograph, 50 times magnification. Paper fibres and sand grains are easily identified. Cement grains and hydration products are unidentified.

To better understand the microstructure of the surface, a higher magnification was used for identification of the cement structure. Figure 88 shows the CEMCEL Bricks at 100 times magnification. Here, the hydrated cement can be identified as spots on the sand grains where the pincers has cut.

Figure 88. SEM photograph, 500 times magnification. Paper fibres, sand grains, cement grains and hydration products are identified.

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Figure 89 shows the cut surface at 2500 times magnification. At this magnification, the calciumsilicatehydrate needles can be identified. They seem to be shorter than 15 Âľmm, which was what was used in section 6.6.2 as the average needle length.

Figure 89. SEM photograph, 2500 times magnification. Hydration products are identified. The calciumsilicatehydrate needles can be identified.

The internal surface in the pores is found to very different from the broken surface. Figure 90 shows a section where the internal surface of the pores can easily be compared with the broken surface. The pore surface seems to be smooth. The perimeter between the two surfaces is a fine white line, indicating a high density with a low porosity. A part of this perimeter is lined up yellow on Figure 90.

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Figure 90. SEM photograph, 125 times magnification. Breakage from cutting with pincers reveals the internal pore surface structure.

The outer surface of the CEMCEL Brick differs from the internal, as fibres are bended from the formwork, Figure 91. It seems that the surface might have a lower porosity than the internal brick. This could have local influence on the material properties of the surface, making them slightly different from the rest of the brick.

Figure 91. SEM photograph, 150 times magnification. Outer surface of the brick.

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8.8.5 Energy Dispersive X-ray Spectroscopy analysis

8.8.5.1 Spectrum analysis The elemental composition for the first and the second EDX analysis is shown in Figure 92 and Figure 93. It shows some variation between the elemental compositions at different locations in the brick. However, the results are in good correlation with the chemical composition of cellulose fibres and cement. Cellulose fibres are polymers of cellulose, (C6H10O5)n [15]. Generally, dried wood of any kind contains approx. 50 % Carbon, 45 % oxygen, 6 % Hydrogen and a number of small amounts of other elements, nitrogen, calcium and others [19]. The high level of calcium comes from the hydrated calciumsilicates and the aluminium from the fewer calciumaluminates.

Figure 92. 1th analysis. Left, mapping spectrum. Elemental composition is revealed using spectrum analysis. Right, the elemental composition is quantified for the sought elements. Minor components from other elements are filtered out. The composition is given in relative weight-%.

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Figure 93. 2nd analysis. Left, mapping spectrum. Elemental composition is revealed using spectrum analysis. Right, the elemental composition is quantified for the sought elements. Minor components from other elements are filtered out. The composition is given in relative weight-%.

8.8.5.2 Elemental distribution To conclude on the elemental composition, it is also relevant to investigate how the elements are located and distributed, Figure 94 and Figure 95. The carbon and oxygen is concentrated on the cellulose fibres. Apart from the high concentrated areas, oxygen is also evenly distributed in the remaining from the hydration products. This confirms the chemical composition of the paper fibres. The calcium, aluminium and silicon are more evenly concentrated, though especially silicon is represented in a number of high concentration areas.

Figure 94. Testing 1. Mapping of elemental composition. First picture top left is a reference image of the specimen. Other pictures indicate how the respective elements are located using the following abbreviations: CK- Carbon, OK- Oxygen, AlK- Aluminium, SiK- Silicon, CaK- Calcium.

Page 98 of 106

Figure 95. Testing 2. Mapping of elemental composition. First picture top left is a reference image of the specimen. Other pictures indicate how the respective elements are located using the following abbreviations: CK- Carbon, OK- Oxygen, AlK- Aluminium, SiK- Silicon, CaK- Calcium.

8.8.6 Concise conclusion Whether the paper fibres are pulped mechanically or chemically has impact on the fibres surface and length. Using mechanically pulping, the surface is roughened and the length shortened from the cutting process. The CEMCEL Bricks pore surface is smooth and seems to be denser than the surrounding brick material. The CEMCEL Bricks outer surface seems to have a lower porosity than the internal brick. The elemental composition between carbon, oxygen, aluminium, silicon and calcium is; carbon 18 % to 22 %, oxygen 44 % to 45 %, aluminium 0.15 % to 0.30 %, silicon 2 % to 4 % and calcium 30 % to 35 %. This is in coherence with the elemental composition of paper fibres and cement. The elemental distribution confirms the elemental composition of the paper fibres. Oxygen, aluminium, silicon and calcium are evenly distributed with a few high concentration areas.

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8.9 Concise conclusion of chapter 8

water to dry mass ration, u [weight-%]

Based on the experiments performed in chapter 8, the material properties in Table 13 are derived. Table 14, part 1. Material properties for the CEMCEL Bricks Name Symbol Measurement Reference Open porosity po 36 % 8.2.7.1 3 Dry density ρd 1664 kg/m 8.2.7.2 Solid density ρs 2601 kg/m3 6.7.9 3 Saturated surface dry density ρssd 2022 kg/m 8.2.7.4 Water absorption coefficient k 0.090 kg/(m2*s1/2) 8.3.4.2 Resistance coefficient m 7.64 * 106 s/m2 8.3.4.2 8.5.4.1.1 Sorption isotherm 15,15%

16,00% 14,00% 12,00% 10,00% 8,00% 6,00%

2,99%

4,00%

2,00%

1,13%

0,00%

1,13%

40,00%

2,74% 50,00%

60,00%

70,00%

80,00%

90,00%

100,00%

Relative humidity [%] Desorption

Thermal conductivity, u = 19.1weight-%. Thermal conductivity, u = 1.8 weight-%. Shrinkage when desorption from freshly cured to 50 % RH Shrinkage when desorption from freshly cured to 85 % RH Shrinkage when desorption from 85 % RH to 50 % RH Swelling when absorption from 50 % RH to 85 % RH Compression strength

Adsorption

u

0.74 W/(m*K)

8.4.5

u

0.43 W/(m*K)

8.4.5

-

0.075 %

8.5.4.1.2

-

0.050 %

Appedix 18

-

0.025 %

Appedix 18

-

0.018 %

Appedix 18

fc

3.7 MPa

8.6.4

Page 100 of 106

Table 14, part 2. Material properties for the CEMCEL Bricks Indexed compression strength for the CEMCEL Bricks using 8.6.5 mechanically pulped paper fibres (P1), using chemically pulped 8.6.6 paper fibres (S1) and at different w/c-ratios (S3). Index 1 = 3.7 MPa (P1). Stress/Strain

Index stress [-] 1,2

P1, w/c=1,0

1

S1, w/c=1,0 S3, w/c = 1,1

0,8

S3, w/c = 1,2

0,6 S3, w/c = 1,3

0,4

S3, w/c = 1,4

0,2

0 0

2

4

6

8

10 Strain [0/00]

Elemental composition of the CEMCEL Bricks. The percentages are relative to the sum of the five elements. Hence, other elements are not accounted for, i.e. hydrogen.

C O Al Si Ca

18 %-22 % 44 %-45 % 0.15 %-0.30 % 2 %-4 % 30 %-35 %

8.8.6

Table 14. Material properties for the CEMCEL Bricks determined in Chapter 8.

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9 Conclusion It is possible to effectively use paper fibres in building bricks with practical utility. Composition and production guidelines are outlined below. When using the aggregate materials in this project, the composition boundaries limit the paper fibre content to 3.7 vol-% in dry state or 19 vol-% in fibre and lumen saturated outer surface dry state (f.l.s.s.d.-state) of the total aggregate. The remaining aggregates are 50 vol-% 0-4 mm sand and 31 vol-% of 4-8 mm stones. To maintain economic incentive and secure sufficient strength, the cement content should be 290 kg/m3, with a w/c-ratio of 1.0. Due to the relatively low content of paper cellulose fibres, the bricks are named CEMCEL Bricks (CEMent and CELlulose paper fibre Bricks), instead of paper based bricks. The CEMCEL Bricks should be shaped inside the production mould using compression until the mortar is water saturated and starts to release free water. Based on the experimentally found material properties, the CEMCEL Bricks are considered to have general practical utility as building bricks. The assessment involves circumstances that must be considered. These are outlined below. After curing for 45 days, the CEMCEL Bricks have a water content of 10-19 weight%. At this state the compression strength is 3.7 MPa. This compression strength is postulated to increase after building, as the CEMCEL Bricks dry. When the CEMCEL Bricks dries, moisture related deformation occurs. A CEMCEL Brick cured for 45 days with a water content of 10-19 weight-% will shrink 0.075 % when dried to 50 % RH at 32 °C. To avoid hazardous coherent tension stresses, the CEMCEL Bricks should be sundried after curing but before building. The CEMCEL Brick’s thermal conductivity is 0.74 W/(m*K) after curing and 0.43 W/(m*K) when dry, making insulation properties superior to most reference materials. The potential biological deterioration cannot be concluded on from the testing. Higher temperatures seem to have a hampering effect on the growth of fungus. The feasibility of the bricks as a building material in relation to the slums in Rasoolpura is evaluated low. The concluding circumstances are described below. During the Field Study in Rasoolpura, Annex 2, it became evident that the slum dwellers successfully use Mud Bricks. Mud Bricks are low tech, low cost and produced locally. The Mud Bricks have been used since ancient time and produced through try and error processes. The coherent composition, production and building techniques are refined and well integrated. The derived properties of the CEMCEL Bricks are generally superior to those of the Mud Bricks, i.e. the lower thermal conductivity and lower density. However, these are of less importance for the specific project case of Rasoolpura, where the houses are not air-conditioned and buildings are single storey. Finally, the composition and production of the Mud Bricks is simpler than that of the CEMCEL Bricks. Though the Mud Bricks in Rasoolpura have good practical utility, they don’t offer a solution to the waste paper problem, like the CEMCEL Bricks does.

10 The project in perspective If India seeks to improve the living standard of the Rasoolpura slum dwellers, the building materials are not the main barrier. Instead, they must address other issues such as highly health hazardous sewage systems, poor sanitation and poor governmental schools. If the waste problems in India are to be effectively dealt with, the general attitude towards littering and waste separation must be improved on a consumer level. On a national level, the value of the raw materials hidden in the waste must be realised and sought recovered by implementing basic recycling systems or waste separation at the landfills. Presently, waste separation is only performed illegally by the so called rag pickers. To further identify the practical utility of the CEMCEL Bricks, the economic perspective must be addressed to clarify the total cost of the CEMCEL Bricks in comparison to conventional building materials. Today’s global situation demands that the environmental perspective is also addressed. The environmental cost in terms of CO2 should be clarified. Cement is used as binding agent in the CEMCEL Bricks. Alternatives with less or no embedded energy should be considered and tested as substitutes. The study of Novozym 51003 enzymes from Novozymes were a spinoff from the project. They proved to have binding effect to cellulose fibre materials. Because the study was a pilot study, Novozym 51003 should be further tested to reveal the full potential of using enzymes as a binding agent in cellulose fibre based materials.

Page 103 of 106

References [1] Thoraya Ahmed Obaid, Executive Director: State of world population report 2007, United Nations Population Fund, 2007. [2] Ingeniører Uden Grænser; www.iug.dk [3] Rafay Salman and Nitya Malladi, Low cost housing: Microsoft PowerPoint presentation, Muffakham Jah College of Engineering and Technology, 8-2-249, Road no. 3, Banjara Hills, Hyderabad – 500034, India. [4] Finn R. Gottfredsen and Anders Nielsen, Bygningsmaterialer Grundlæggende egenskaber, 1.udgave. Polyteknisk forlag, 1997. [5] Anders Nielsen, Silikatbygningsmaterialer. Laboratoriet for Bygningsmaterialer, Technical University of Denmark, 1993. [6] Ole Mejlhede Jensen, Autogenous Phenomena in Cement-Based Materials. Department of Building Technology and Structural Engineering, Aalborg University, 2005. [7] Kenneth Strømdahl, Water Sorption in Wood and Plant Fibres. Department of Structural Engineering and Materials, Technical University of Denmark, 2000. [8] Torben C. Hansen, Beton I henhold til DS 411-84, Department of Civil Engineering- Building Material Laboratory, Technical University of Denmark, 1985. [9] DS/EN 12350-2:2002, Prøvning af frisk beton, Dansk Standard, 2002. [10] Aalborg Portland, Cement og beton, 17. udgave, Aalborg Portland, 2002. [11] Alfred J. Stamm, Wood and cellulose science, The Ronald Press Company, 1964. [12] Anders N. D. Mørk, Svind- og svelningsmålinger I behandlet og ubehandlet træ, Department of Civil Engineering, Technical University of Denmark, 2007. [13] Beton-Teknik Portlandcementer, Cementfabrikkernes tekniske Oplysningskontor, Aalborg Portland, rev 1999. [14] L. P. B. M. Janssen and M. M. C. G. Warmoeskerken, Transport Phenomena Data Companion, Edward Arnold and Delft University of Technology, 1987. [15] Bygningsingeniørernes materialer - Uddrag af Materialebogen, 1. Udgave, Nyt Teknisk Forlag, 2008. [16] T. A. Munch and K. K. Hansen, Vejledning til måling af varmeledningsevne for tørre og fugtige materialer, Technical University of Denmark, 2003. [17] Carsten Bredahl Nielsen, Brugervejledning til SKANFRYS, Danmarks Tekniske Højskole, 1992 Page 104 of 106

[18] Carsten Lygum and Mads Prange Kristiansen, Porebeton som primær bygningsdel i et enfamilieshus, Department of Civil Engineering, Technical University of Denmark, 2007. [19] D. Fengel, G. Wegener, Wood chemistry ultrastructure reactions, de Gruyter, 1993. [20] Per Goltermann, Load-carrying capacity of lightly reinforced lightweight aggregate concrete walls, Department of Civil Engineering, Technical University of Denmark. [21] Kurt Kielsgaard Hansen, Grusprøvning, 11561 Bygningsmaterialer – anvendelse og forsøg, Department of Civil Engineering, Technical University of Denmark. [22] Wikipedia, the free encyclopedia, www.wikipedia.org [23] Webpage of Auroville, www.auroville.org

Page 105 of 106

Appendix overview 1. Meeting with Professor Ali Ansari. Introduction to EWB from IUG and Prof. Ali Ansari. 2. Visit at Papiruld Danmark ApS. Guided tour at production facilities. 3. Sieving curve for lake materials. 4. Gravimetric water content of paper fibres from Papiruld Danmark ApS on delivery. 5. Summary of discussion with Associate Professor Staffan Svensson. 6. Summary of discussion with Associate Profes.sor Staffan Svensson and Associate Professor Kurt Kielsgaard Hansen 7. Water absorption in cellulose fibres dependency on time. Determination of fibre and lumen saturated outer surface dry point density of paper fibres 8. Formulas used as reference for derivation of specific surfaces. 9. Derivation of aggregate specific surface and maximum average distance between particles. 10. Point of reference formula for determination of slump dependency on water content in paper based cement mortar. 11. Slump dependency on water content in paper based cement mortar. 12. CEMCEL formula. Design sketch for CEMCEL bricks formwork. 13. Density and porosity results. 14. Capillary suction results. 15. Thermal conductivity logging data. 16. Thermal conductivity calculations and results. 17. Equilibrium water content at the different humidity levels. 18. Moisture related deformation 19. Summary of discussion with Per Goltermann 20. Formulas for sensitivity analysis 21. Stress/strain- relation curves for primary testing 22. Stress/strain- relation curves for secondary and tertiary testing 23. Product sheet, Novozym 51003

Page 106 of 106

bre Base ed Brickks fo or Paperr Fib ow Cost C using in Deve D lopin ng Hou Lo C Count tries A Appen ndixe es Ma ads Prang ge Kristia ansen

MSc Thesis project p in Civil C Engine eering, 200 09

s032486

Appendix overview 1. Meeting with Professor Ali Ansari. Introduction to EWB from IUG and Prof. Ali Ansari. 2. Visit at Papiruld Danmark ApS. Guided tour at production facilities. 3. Sieving curve for lake materials. 4. Gravimetric water content of paper fibres from Papiruld Danmark ApS on delivery. 5. Summary of discussion with Associate Professor Staffan Svensson. 6. Summary of discussion with Associate Profes.sor Staffan Svensson and Associate Professor Kurt Kielsgaard Hansen 7. Water absorption in cellulose fibres dependency on time. Determination of fibre and lumen saturated outer surface dry point density of paper fibres 8. Formulas used as reference for derivation of specific surfaces. 9. Derivation of aggregate specific surface and maximum average distance between particles. 10. Point of reference formula for determination of slump dependency on water content in paper based cement mortar. 11. Slump dependency on water content in paper based cement mortar. 12. CEMCEL formula. Design sketch for CEMCEL bricks formwork. 13. Density and porosity results. 14. Capillary suction results. 15. Thermal conductivity logging data. 16. Thermal conductivity calculations and results. 17. Equilibrium water content at the different humidity levels. 18. Moisture related deformation 19. Summary of discussion with Per Goltermann 20. Formulas for sensitivity analysis 21. Stress/strain- relation curves for primary testing 22. Stress/strain- relation curves for secondary and tertiary testing 23. Product sheet, Novozym 51003

Appendix 1 Page 1 of 8

Meeting with Professor Ali Ansari Subject Concerning MSc project; Paper Based Bricks for Low Cost Housing in Developing Countries

Time and place 29. September, 2008. Technical University of Denmark (DTU), building 118, room 042

Participants • • • •

Professor Ali Ansari (AA), MJCET Mechanical Engineering, founder-chair of EWB-India and chairman of EWB-International. Associate professor Kurt, Kielsgaard Hansen (KKH), DTU Civil Engineering János Hethey (JH), representative IUG. Mads Prange Kristiansen (MPK), project holder, student DTU Civil Engineering.

Agenda • • • • • • •

Why sticking with paper based bricks Technical clarification Constructional requirements in India Indian climate Experimental planning Ideas for construction General discussion

Appendix 1 Page 2 of 8

Why sticking with paper based bricks MPK – Short description of why sticking with paper based solutions. Plastic fibres extracted from fertilizer bags require technical solutions that are not compatible with the overall concept of low-tech solutions. AA – Agrees. AA directs attention to the UNESCO/Daimler partnership, Mondialogo. Mondialogo hosts competition as joint venture projects between developed and developing countries.

Technical clarification Composite

Wet composition, weight-%

Waste paper pulp

52 22 26 <1

Cement Sand, soil or ash Additives

Composite

Dry composition, weight-%

Waste paper

25 34 41 <1

Cement Sand, soil or ash Additives

Name Dry density Porosity Thermal conductivity Specific heat capacity Water vapour permeability Young's modulus Compression strength, cracking

Symbol ρ p λ cp δ E fc

Given units 3 g/cm 0.539 80 % 2 2-3 Btu/ft °F*h 2 kg/cm 9.52

Compression strength, crushing

fc

67.46

coefficient of linear expansion Moisture related strain, wet to 50 % RH

α -

-

kg/cm

2

-

converted SI units 3 kg/m 539 80 % 0.29-0.43 W/(m*k) J/(kg*K) - kg/(Pa*m*s) GPa 0.9 MPa 6.6

MPa

-

°C 0 /00

-1

Appendix 1 Page 3 of 8 Cellular concrete, medium Bricks, hard density burned Unit 3 kg/m 500 1800 80 30 % 0.12 0.35-0.58 W/(m*k) 960 960 J/(kg*K)

Name Dry density Porosity Thermal conductivity Specific heat capacity

Paper based brick Symbol ρ 539 p 80 λ 0.29-0.43 cp -

Water vapour permeability Young's modulus Compression strength, cracking

δ E fc

- 70 * 10 15 0.9 -

Compression strength, crushing

fc

6.6 -

7.5*10 0.65

coefficient of linear expansion Moisture related strain, wet to 50 % RH

•

α -

-12

30*10 15 -

-12

kg/(Pa*m*s) GPa MPa

2.5

65

MPa

-6

5.5*10 0.0075

-6

°C 0 /00

U-value 2-3/inch- How transformed to EU standard?

AA - The R-value had the unit ft2 * °F * h / Btu Conversion factor is; 1 ft2 * °F * h / Btu = 0.1761 K * m2/W. Calculations performed after meeting: 1 1 R = = = 0.5 ft 2 *°F*h/Btu=0.5*0.1761 K*m 2 / W = 0.08K*m 2 / W U 2 d d 1inch 0.0254m R= ⇒λ = = = = 0.29W / m * K 2 λ R 0.08K*m / W 0.08K*m 2 / W Hence, the thermal conductivity, λ=0.29 W/m*K – 0.43 W/m*K •

Composition o Type of paper used/available AA - Newspapers, cardboard boxes, raw paper with no gloss o Cement used/available AA - Normal Portland cement o Lime instead of cement ÁA – Was used in India earlier instead of cement, therefore tried now as an alternative. Not usually used anymore. o Sand, soil, ash used/available AA – Don’t know. Will forward question to engineers at MJCET.

•

Compression before hardening

-1

Appendix 1 Page 4 of 8 AA – Specimens were at no point compressed in the process. •

Purpose of lime coating, common available coatings

NIL •

How is pulp consistency obtained- mechanically/ chemically

AA – Consistency is obtained mechanically.

Constructional requirements/norms/regulations in India •

Typical mortar

AA – Cement based, as in Denmark •

Typical wall

AA – Solid, single •

Typical foundation AA – Not concrete. Natural stones, 1-2 feet above ground level. Codes exists, but not necessarily followed, no control whatsoever- common sense. Will forward question to engineers at MJCET.

•

Typical surface treatment requirements AA - Codes exists, but not necessarily followed, no control whatsoevercommon sense. Will forward question to engineers at MJCET.

•

Official demands for; o Compression strength o Insulation properties o Moisture properties AA - Will forward question to engineers at MJCET.

•

Method concerning doors and windows

AA – Doors and windows not likely to exist in these houses.

Appendix 1 Page 5 of 8

Indian climate General discussion on climate conditions in India. India has many climate zones and slums exist in all of them, making it impossible to determine representative conditions. MPK – Decision on case selection, Hyderabad, where MJCET is located.

Figure 1. Location of case, Hyderabad, Andhra Pradesh, India.

General conditions for slum housing in India. Houses are of very poor condition. A household of 5-6 people will have one or two rooms and a total approximated ground area of 7.0 m * 5.0 m in rural areas and half of this in urban areas. Assumable no windows and poor doors. Climate conditions (RH, temp, sunshine hours, rain amount) for Hyderabad for winter, summer and monsoon will be sought after at MJCET. Indoor comfort, RH 40-65%. Temp 25-28°C.

Appendix 1 Page 6 of 8

Experimental planning

AA – Suggestion seems sound.

Appendix 1 Page 7 of 8

Ideas for construction

AA – Suggestion seems sound.

Appendix 1 Page 8 of 8

Introduction to EWB from IUG and Prof. Ali Ansari Below the formal invitation;

General introduction to the organisation. Project at hand referenced on a few occasions. Inter alia as an example on how project initiative may come from developed countries, whereas initiative usually comes from the location of the needs, i.e. the developing country. Through his presentation, AA emphasized that “simple solutions is the answer” to many of developing countries’ problems.

Appendix 2 Page 1 of 5

Visit at Papiruld Danmark ApS General info Address: Papiruld Danmark ApS, Brødeskovvej 40, 3400 Hillerød Telephone: 4814 1188 Fax: 4814 1185 E-mail: info@papiruld.dk

Time and place 10. October, 2008. Brødeskovvej 40, 3400 Hillerød.

Participants • • •

Claus Skov (CS), Manager and part owner ?, Production Manager and part owner Mads Prange Kristiansen (MPK), project holder, student DTU Civil Engineering.

Agenda • •

Questions from MPK to CS and general discussion and introduction Tour at the productions facilities with Production Manager.

Questions 1. General about Papiruld Danmark ApS 55 % higher growth third quarter this year compared to last year. Listed as growth company number 313 in newspaper Børsen, compared to number 1806 last year. The production has a shift of three people at a time. 2. Kind of paper in production Ordinary newspaper, no glittered paper. The additives in glittered paper press the air out of the fibres. 3. Pre-treatment, paperclips Paperclips are taken out using magnets. Furthermore, they are naturally deposited through the machines and transportation between machines. 4. Ink treatment Newspapers are subject to the same stringent requirements as food. Ink is organic only. No additional treatment is done with respect to the ink. A visit to Maglemølle paper production recommended by CS. 5. Datasheet Kurt Kielsgaard Hansen has all the datasheets. Datasheet handed out, shown below in Figure 1. 6. General discussion MPK wishes to use Papiruld as an alternative to “homemade” paper pulp to save time. CS expects that paper pulp from Papiruld will perform poorer than homemade since the fibres are cut and hence shorter. CS wishes a one page description indicating how the project benefits from his product. He also wants a copy of the report. MPK grants both. CS states stat cellulose fibres are proven much stronger than those of steel.

Appendix 2 Page 2 of 5

Figure 1. Datasheet for Papiruld

Appendix 2 Page 3 of 5

Guided tour at production facilities 1. Waste paper from newspaper productions etc. is stored on site. Waste paper still contains potential metals from clips etc. Paper cannot be glitted or otherwise treated. The raw paper used is potentially consumeable as additive requirements on recycled paper demands it.

2. Paper is lifted onto the production band

3. Paper is lifted into the first rough grinder.

Appendix 2 Page 4 of 5

4. Metals are naturally deposited at the first grinder from the gravity force.

5. The paper goes through two more grinders, medium and fine, in which further potential metals is removed with magnetes.

6. Paper is impregnated with three different fire restraining salts, Aluminumhydroxid (Al(OH)3) and two different Borax salts. These all give off water when exposed to fire, but at different temperatures, making a three- levelled fire restraining effect. Before the paper goes to the packing facility, fine dust is removed.

Appendix 2 Page 5 of 5

7. At the plastic packing facility, the paper fibres are vacuum packed to 25 % of their size. When removed from the plastic packing, the fibres will regain their full original size.

8. The squared plastic bags optimized packing potential and are packed on pallets, ready for transportation.

The pallets are stored outside, as the packing is air and water proof, making storage easy and cost effective.

Appendix 3 Page 1 of 2

Sieving curves for lake materials Date for sieving curve, class. A 0-4mm 09.12.2008 MPK, second measurement Sieve Sieve weight Sieve+material Retained Fall through ÎŁ% mm g g g g 64 0 0 0 132 100,0 32 0 0 0 132 100,0 16 0 0 0 132 100,0 8 0 0 0 132 100,0 4 414,23 416,13 1,9 130 98,6 2 381,32 392,46 11,14 119 90,1 1 347 363,19 16,19 103 77,9 0,5 308,28 333,03 24,75 78 59,2 0,25 282,39 328,57 46,18 32 24,2 0,125 270,2 298,42 28,22 4 2,9 0,075 243,28 247,09 3,81 0 0,0 Total 132,19

Sieving curve Mads Prange Kristiansen BYG*DTU

100 90

Fall through, weight %

80 70 60 50 40 30 20 10 0

0,125 0,25

0,1

0,5 0,4 Sand

11

2

4

Sieve width mm

Figure 1. 0-4 mm lake sand. Average size 0,4 mm

8

10

16

32

Stones

64

100

Appendix 3 Page 2 of 2 Sigte mm 64 32 16 8 4 2 1 0,5 0,25 0,125 0,075 Bund Total

Date til dannelse af sigtekurve søsten kl. A 4-8mm 15.01.2007 EC Sigtens vægt Sigte+materiale Tilbageholdt Gennemfald Σ% g g g g 1400 1400 0 2999 100,0 1405,3 1405,3 0 2999 100,0 1375,2 1375,2 0 2999 100,0 1412,1 1490,7 78,6 2920 97,4 1213,9 3827,2 2613,3 307 10,2 1178,5 1468,9 290,4 17 0,6 1145 1156,8 11,8 5 0,2 1053,1 1056 2,9 2 0,1 977,8 978,5 0,7 1 0,0 1047,7 1048 0,3 1 0,0 1028,9 1029,1 0,2 1 0,0 751 751,6 0,6 0 0,0 2998,8

Sigtediagram Lavet af Erik Christensen BYG*DTU

100 90

Gennemfald (vægt) %

80 70 60 50 40 30 20 10 0

0,125 0,25

0,1

0,5 Sand

11

2

4

8

Sigtemaskevidde mm

10

16

32

Sten

Figure 2. 4-8 mm lake stones, Erik Christensen measurements. Average size 5,8 mm

64

100

Appendix 4 Page 1 of 1

Gravimetric water content of paper fibres from Papiruld Danmark ApS on delivery Specimen m, petri dish [g] m, petri dish, delivery [g] m, petri dish, dry [g] m1 [g]

1 395,19 524,82 514,47 129,63

2 391,55 525,26 514,6 133,71

3 403,18 531,51 521,08 128,33

4 Average 385,08 520,31 509,62 135,23

m0 [g] 119,28 123,05 117,9 124,54 u [weight- %] 8,6771 8,6631 8,8465 8,5836 8,69257 Figure 1. Gravimetric water content of paper fibres from Papiruld Danmark ApS on delivery

Appendix 5 Page 1 of 2

Summary of discussion with Associate Professor Staffan Svensson Subject f.s.p.-density and paper fibre swelling.

Time and place 30- October, 2008. Technical University of Denmark (DTU),

Participants • •

Associate professor Staffan, Svensson (SS), DTU Civil Engineering Mads Prange Kristiansen (MPK), project holder, student DTU Civil Engineering.

Discussion MPK – Testing procedure modified by MPK from existing procedure for sand presented to SS. SS explains that there exists a method for testing f.s.p.-density for wood pieces, Figure 1. The setup measures the upward force applied when the wood is submerged in the water. When the force is constant, the wood is saturated and can be measured and weighted for determination of f.s.p. - density.

Figure 1. Illustration of experimental setup for testing of saturated fibre point density for wood.

MPK/SS – agrees that this method is useless for loose fibres, as a prerequisite is that the material is a solid. MPK/SS – Discussion on the testing procedure presented by MPK. Agreement that the theory of the procedure is solid and the testing believed practically useful. MPK/SS – When paper fibres are gradually saturated, the cell walls are saturated before the lumens begin to saturate. This is due to the much smaller pores in the cell wall, resulting in a higher hydrostatic negative pressure. SS – Explains that paper fibres only expand when saturated until approx. 35 weight %, equalling the level where the cell walls are saturated. In Figure 2, this is indicated by a bend in the relative density/moisture content curve.

Appendix 5 Page 2 of 2

Figure 2. Relative density, moisture content curve. The curve bends after approx 35 weight- %, when the cell walls are saturated. The swelling stops and hence, the relative density increases.

The lumen saturation practically doesn’t expand the fibres. Loose fibres expand up to 32 %.

Appendix x6 Page 1 of 3

Su ummary y of disc cussion n with Associatte Profe essor Sta affan Sv vensson and Associa A te Profe essor K Kurt Kie elsgaarrd Hansen Su ubject Inteeraction of water betweeen cement and cellulosse fibres in the hardeniing process

Tim me and place p 20- October, 20008. Techniical Universsity of Denm mark (DTU U),

Participantts • • •

Associaate professoor Staffan, Svensson S (SS), DTU Ciivil Engineeering Associaate professoor Kurt, Kielsgaard Han nsen (KKH)), DTU Civvil Engineeriing Mads Prange P Kristtiansen (MP PK), projectt holder, stuudent DTU C Civil Engineeering.

Dis scussion n MPK – The challenge is too determinee how much h of the wateer in the celllulose fibrees thatt can be connsidered freee, hence avaailable to th he cement hyydration. W With sand, th he satuurated surfacce dry (s.s.dd.) state is used, u as show wn in Figurre 1. In the ss.s.d. condittion, no water w is freee on the graain surface. The T water in i the open and concealled pores will w not contribute to t the cement hydrationn.

Figuure 1. Sand grrain in s.s.d. coondition

SS – With celluulose fibres, the case iss more comp plex. Woodd fibres can hold a subsstantial amoount of liquid water in the lumen in i addition to t the smalll amount of liquuid water fouund on the surface s of thhe fibres orr bundles off fibres. But before liqu uid water can be prresent in lum men or on any a outer su urfaces the wood w materiial must be satuurated. The wood w fibre cell-wall chhemically binds water therefore t caalled bound water and a satturated cell--wall contains 35 mass percentages water. In Figure 2, a skettch of a woood fibre is shown s with the differen nt types of water w indicaated.

Appendix 6 Page 2 of 3

Figure 2. Illustration of water storage in a single cellulose fibre. a) Free surface water on the fibre. b) Chemical bound water in the cell wall. c) Liquid water in the cell lumen.

SS – The lumen holds 150 – 200 % kg water / kg wood. This water can be released almost immediately and should be considered free. The cell wall holds 30 – 35 % kg water / kg wood. This water is released over time depending on the suction pressure from the cement. The release takes hours/days. Therefore, the cellulose fibres should be considered as a moisture buffer- the efficiency of this buffer should be investigated. KKH – These abilities draws parallels to Superabsorbent Polymers (SAP) theory. The theory of Ole Mejlhede Jensen Doctor Thesis should be looked into [6]. KKH – The level of water desorption from the cellulose fibres could be investigated by mixing a number of cement, paper pulp pastas and measuring the RH as to seek at which water content the RH drops below 100 % indicating no free water. SS/KKH/MPK - The cement absorbs water with a certain suction pressure, -Pac. By using this pressure as input in a pressure plate apparatus, described in Kenneth Strømdahl’s Ph.D Thesis [7], the moisture content at the pressure state of equilibrium can be determined. At this state, the cement can no longer absorb water from the paper pulp.

Figure 3. Diagram illustrating determination of pressure state of equilibrium.

Appendix 6 Page 3 of 3 There is consensus that this method should be tested. SS – Thesis from Benjamin J. Mohr touches the subject of cement and cellulose fibres mixing. KKH – Until further clarification, two w/c ratios must be used, One including the cell wall water, one excluding it.

Appendix 7 Page 1 of 5

Appendix 7.1 Water absorption in cellulose fibres dependency on time Capillary suction of water in cylindrical pores Capillary suction is defined as a materials water suction through its capillaries when brought in contact with water. For water in liquid form, this happens through non stationary moisture transport, which is depending on time. This is how water is absorbed into the cellulose fibre lumen. Hence the correlation between the f.l.s.s.d.state and time.

Figure 1. Idealized figure showing capillary suction in a capillary, which can be compared to that in cellulose fibres. Surface tension of water creates a hydrostatic pressure below the meniscus so that the water is sucked up into the capillary. When the water is no longer rising, the hydrostatic pressure is equal to the water gravitational pull and the resistance in the pipe combined [8].

In Figure 1, the idealized circumstances is shown and displayed. The hydrostatic negative pressure, p’ [Pa], can be calculated from Equation 1. 2 cos 2 2 Equation 1

where p [Pa] is the atmospheric pressure, σ [Pa] is the surface tension which is 0,0735 N/m for water at 20°C, θ [°] is the contact angle, rm [m] is the meniscus radius and pore radius, and rK [°] is the Kelvin radius. The second sign of equality is an idealised assumption [4] of θ = 0°, because this has relatively low impact, and rm = rK, indicating that there is no water whatsoever above the meniscus [4]. The second sign of equality neglects the atmospheric pressure, which is the case for horizontal oriented pores. Hereby, the hydrostatic pressure is only slowed by the friction against the pore wall, which is calculated from Equation 2[4], Figure 2. 4 2

Equation 2

Where τ [Pa] is the friction, µ [Ns/m ] is the waters viscosity, z [m] is the suction length and t [s] is the time.

Appendix 7 Page 2 of 5

Figure 2. Simplified illustration of the opposing forces working in a capillary in the balanced state.

By projecting the forces from these two opposing elements into the balanced state, illustrated in Figure 2, where their sum is zero, and then integrating with respect to the time, Equation 3 can be derived. 2 Equation 3. Equation is derived in [11]

Where h [m] is the suction length and t [s] is the time till the corresponding suction length is reached. The equation generally shows that capillary suction happens faster in bigger pores, but has a higher maximum suction height for smaller pores. For a cellulose fibre of 3,5 mm length and a diameter of 30 ¾m [11], using a viscosity of 11*10-4 Ns/m2 found in Figure 3, using a reference temperature of 20 °C, Equation 3 results in a timeframe of t = 0,022 s. The time the fibre contacts the water until the fibre lumen is water filled. Knowing the lumen length and the time needed for water filling of the lumen, the resistance, m [s/m2], can be calculated from Equation 4 to 1796 s/m2.

Equation 4 [4]

Figure 3. Correlation between water dynamic viscosity Âľ and the temperature [4].

Diagrams, Figure 4, have been derived for the above theory for time estimation. When extending the diagram as shown in Figure 4 by handwriting, the above result of t = 0,022 s matches the findings.

Appendix 7 Page 3 of 5

Figure 4. Relation between suction time and suction height, depending on the pore radius. The yellow dot is the diagram result that matches with the calculated time, t= 0,022 s.

Hydrogen bonds between cellulose fibres and water The adsorbtion of water in the cellulose fibre cell wall happens as the water molecules makes hydrogen bonds to the hydroxyl groups in the amorphous components of the cellulose fibre wall, primarily the hemicelluloses. It is difficult to make any precise theoretical estimates on how long this takes for a single cellulose fibre. However, a solid assumption can be made based on woods mechanical properties. Woods mechanical properties change with the water content at water contents below the fibre saturated point (f.s.p.-state). Above the f.s.p.-state, where the cell wall is water saturated, the properties are generally constant. Therefore, the time until this state occurs can be estimated by observing changes in the mechanical properties, e.g. swelling. By submerging a wood piece, and measuring its swelling, the f.s.p.-state can be estimated to have occurred at the time where the wood no longer changes its size. This experiment is reported by bachelor of engineering student, Anders N. D. Mørk’s bachelor project Shrinkage and swelling measurements in treated and untreated wood [12], supervised by Associate Professor Staffan Svensson and Associate Professor Kurt Kielsgaard Hansen, Technical University of Denmark. A principled sketch of the experimental method used is shown in Figure 5.

Appendix 7 Page 4 of 5

Figure 5. Principled setup used in the strain testing [12]. The stop watch measures the time and the dial gauge measures the corresponding strain. When the strain occurs in the test specimen, the strain is transmitted via the metal rod to the gauge.

Figure 6 shows the strain development over time for pinewood. After 25 minutes, there is practically no further strain, indicating that the cell wall is saturated. After 45 minutes, the testing was ended. Pinewood,103 degrees celcius drying 0,1 0,09 Strain [mm/mm ]

0,08 0,07 0,06

Radial direction

0,05 0,04

Tagential direction

0,03 0,02

longitudinal direction

0,01 0 0

5

10

15

20

25

30

35

40

45

Time [min]

Figure 6. Strain development over time for pinewood. The pinewood is dried at 103 °C and then fully submerged in water. The strain is measured until there is practically no further strain development [12].

Appendix 7 Page 5 of 5

Appendix 7.2 Determination of fibre and lumen saturated outer surface dry point density of paper fibres m0

[g]

2756,78

mf.l.s.s.d.

[g]

104,42

m1

[g]

ρw

2768,15 3

[kg/m ] 3

1000

[kg/m ] ρf.l.s.s.d. 1122 Figure 7. Determination of ρf.l.s.s.p. of paper fibres

Appendix 8 Page 1 of 3

Formulas used as reference for derivation of specific surfaces Specifications Sought water need [kg/m3]; Sought w/c - ratio [-]; Sought volumen- % of sand in aggregate Volumen- % of stones in aggregate Volumen- % of waste paper in aggregate

290 1,00 100 0 0

Mortar proportioning

Cement Water Air Sand Stone Waste paper

Density in s.s.dMass kg/m3 kg/m3 3100 1000 0 2650 2650 1122

Mortar Control

2187

Volume m3/m3 0,094 0,290 0,010 0,606 0,000 0,000

290 290 0 1607 0 0 2187

1 100,00%

Mortar formula

Cement Water Air Sand Stone Waste paper

Unadjusted Mass Volume kg/target vol. l/target vol. 2,90 2,90 0,00 16,07 0,00 0,00

Total

22

0,94 2,90 0,10 6,06 0,00 0,00

Target vol. 10,00 Litre Adjusted Adjusted mass Adjusted mass Adjusted Volume Adjusted Volume kg/target vol. % of total l/target vol. % of total 2,90 13 0,94 9 2,90 13 2,90 29 1 0,00 0 0,10 16,07 73 6,06 61 0 0,00 0 0,00 0,00 0 0,00 0

10

21,87

100

10,00

Adjustment for moisture content in aggregate Sand Content of aggregate in s.s.d. state in target volume [kg] Water absorption ability [weight- %] Water content [weight- %] Content of aggregate, adjusted for water content [kg] Adjusted mixing water of aggregate [l]

Figure 1. Formula SA, aggregate is sand only.

Stone 16,07 2 2 16,07 0,00

Paper pulp 0,00 2 2 0,00 0,00

0,00 235 8,69 0,00 0,00

100

Appendix 8 Page 2 of 3 Specifications Sought water need [kg/m3]; Sought w/c - ratio [-]; Sought volumen- % of sand in aggregate Volumen- % of stones in aggregate Volumen- % of waste paper in aggregate

290 1,00 50 0 50

Mortar proportioning

Cement Water Air Sand Stone Waste paper

Density in s.s.dMass kg/m3 kg/m3 3100 1000 0 2650 2650 1122

Mortar Control

1724

Volume m3/m3 0,094 0,290 0,010 0,303 0,000 0,303

290 290 0 804 0 340 1724

1 100,00%

Mortar formula

Cement Water Air Sand Stone Waste paper

Unadjusted Mass Volume kg/target vol. l/target vol. 2,90 2,90 0,00 8,04 0,00 3,40

Total

17

0,94 2,90 0,10 3,03 0,00 3,03

Target vol. 10,00 Litre Adjusted Adjusted mass Adjusted mass Adjusted Volume Adjusted Volume kg/target vol. % of total l/target vol. % of total 2,90 17 0,94 9 5,20 30 5,20 51 1 0,00 0 0,10 8,04 47 3,03 30 0 0,00 0 0,00 1,10 6 0,98 10

10

17,24

100

10,25

Adjustment for moisture content in aggregate Sand Content of aggregate in s.s.d. state in target volume [kg] Water absorption ability [weight- %] Water content [weight- %] Content of aggregate, adjusted for water content [kg] Adjusted mixing water of aggregate [l]

Stone 8,04 2 2 8,04 0,00

Figure 2. Formula P. aggregate is 50 % sand and 50 % paper fibres.

Paper pulp 0,00 2 2 0,00 0,00

3,40 235 8,69 1,10 2,30

100

Appendix 8 Page 3 of 3 Specifications Sought water need [kg/m3]; Sought w/c - ratio [-]; Sought volumen- % of sand in aggregate Volumen- % of stones in aggregate Volumen- % of waste paper in aggregate

290 1,00 50 31 19

Mortar proportioning

Cement Water Air Sand Stone Waste paper

Density in s.s.dMass kg/m3 kg/m3 3100 1000 0 2650 2650 1122

Mortar Control

2011

Volume m3/m3 0,094 0,290 0,010 0,303 0,188 0,115

290 290 0 804 498 129 2011

1 100,00%

Mortar formula

Cement Water Air Sand Stone Waste paper

Unadjusted Mass Volume kg/target vol. l/target vol. 2,90 2,90 0,00 8,04 4,98 1,29

Total

20

0,94 2,90 0,10 3,03 1,88 1,15

Target vol. 10,00 Litre Adjusted Adjusted mass Adjusted mass Adjusted Volume Adjusted Volume kg/target vol. % of total l/target vol. % of total 2,90 14 0,94 9 3,77 19 3,77 37 1 0,00 0 0,10 8,04 40 3,03 30 19 4,98 25 1,88 0,42 2 0,37 4

10

20,11

100

10,09

Adjustment for moisture content in aggregate Sand Content of aggregate in s.s.d. state in target volume [kg] Water absorption ability [weight- %] Water content [weight- %] Content of aggregate, adjusted for water content [kg] Adjusted mixing water of aggregate [l]

Stone 8,04 2 2 8,04 0,00

Paper pulp 4,98 2 2 4,98 0,00

Figure 3. Formula ST. aggregate is 50 % sand,29 % stones and 21 % paper fibres.

1,29 235 8,69 0,42 0,87

100

Appendix 9 Page 1 of 1

Derivation of aggregate specific surface and maximum average distance between particles Specific surface of aggregates ρf.l.s.s.d./ρs.s.d. [kg/m3]

d [m] 400,0E-6 5,8E-3 30,0E-6

Specific surface Sand Specific surface Stone Specific surface Waste paper Specific surface aggregate

2650 2650 1122

S [m2/kg]

m [kg/m3]

5,7 0,4 186,7 5,7

1634 0 0

Maximum distance between cement particles Particle diameter [m] 15,0E-6 Particle mass, cement [kg] 5,5E-12 Particle number, pr. kg cement [kg-1] 182,5E+9 Particle number, pr. kg aggregate [kg-1] 24,0E+9 Maximum distance, d [m] 7,9E-06

Figure 1. Formula S Specific surface of aggregates ρf.l.s.s.d./ρs.s.d. [kg/m3]

d [m] 400,0E-6 5,8E-3 30,0E-6

Specific surface Sand Specific surface Stone Specific surface Waste paper Specific surface aggregate

2650 2650 1122

S [m2/kg]

m [kg/m3]

5,7 0,4 186,7 59,5

817 0 346

Maximum distance between cement particles Particle diameter [m] 15,0E-6 Particle mass, cement [kg] 5,5E-12 Particle number, pr. kg cement [kg-1] 182,5E+9 Particle number, pr. kg aggregate [kg-1] 30,5E+9 Maximum distance, d [m] 25,5E-06

Figure 2. Formula P. Specific surface of aggregates ρf.l.s.s.d./ρs.s.d. [kg/m3]

d [m] Specific surface Sand Specific surface Stone Specific surface Waste paper Specific surface aggregate

400,0E-6 5,8E-3 30,0E-6

Maximum distance between cement particles Particle diameter [m] 15,0E-6 Particle mass, cement [kg] 5,5E-12 Particle number, pr. kg cement [kg-1] 182,5E+9 Particle number, pr. kg aggregate [kg-1] 26,1E+9 Maximum distance, d [m] 14,9E-06

Figure 3. Formula ST

2650 2650 1122

S [m2/kg] 5,7 0,4 186,7 20,2

m [kg/m3] 817 507 131

Appendix 10 Page 1 of 2

Point of reference formula for determination of slump dependency on water content in paper based cement mortar Specifications Sought water need [kg/m3]; Sought w/c - ratio [-]; Sought volumen- % of sand in aggregate Volumen- % of waste paper in aggregate

230 0,8 25 75

Mortar proportioning

Cement Water Air Sand Waste paper

Density in s.s.d. state Mass kg/m3 kg/m3 3100 288 1000 230 0 0 2650 382 1122 486

Mortar Control

1386

Volume m3/m3 0,093 0,230 0,100 0,144 0,433

1386

1 100,00%

Mortar formula Unadjusted Mass kg/target vol. Cement Water Air Sand Waste paper Total

2,01 1,61 0,00 2,68 3,40

Volume l/target vol. 0,65 1,61 0,70 1,01 3,03

10

7

7,00 Litre Adjusted Adjusted mass Adjusted mass Adjusted Volume kg/target vol. % of total l/target vol. 2,01 21 0,65 3,91 40 3,91 0,00 0 0,70 2,68 28 1,01 1,10 11 0,98 9,70

100

2,68 2 2 2,68 0,00

Paper pulp 3,40 235 8,69 1,10 2,30

Adjustment for moisture content in aggregate Sand Content of aggregate in s.s.d. state in target volume [kg] Water absorption ability [weight- %] Water content [weight- %] Content of aggregate, adjusted for water content [kg] Adjusted mixing water of aggregate [l]

Figure 1. Formula for paper based cement mortar with 75 volume % paper fibres and 25 volume % sand.

7,25

Appendix 10 Page 2 of 2 Specifications Sought water need [kg/m3]; Sought w/c - ratio [-]; Sought volumen- % of sand in aggregate Volumen- % of waste paper in aggregate

230 0,8 50 50

Mortar proportioning

Cement Water Air Sand Waste paper

Density in s.s.d. state Mass kg/m3 kg/m3 3100 288 230 1000 0 0 765 2650 324 1122

Mortar Control

1606

Volume m3/m3 0,093 0,230 0,100 0,289 0,289

1606

1 100,00%

Mortar formula Unadjusted Mass kg/target vol. Cement Water Air Sand Waste paper Total

2,01 1,61 0,00 5,35 2,27

Volume l/target vol. 0,65 1,61 0,70 2,02 2,02

11

7

7,00 Litre Adjusted Adjusted mass Adjusted mass Adjusted Volume kg/target vol. % of total l/target vol. 2,01 18 0,65 3,14 28 3,14 0,00 0 0,70 5,35 48 2,02 0,74 7 0,66 11,24

100

5,35 2 2 5,35 0,00

Paper pulp 2,27 235 8,69 0,74 1,53

7,17

Adjustment for moisture content in aggregate Sand Content of aggregate in s.s.d. state in target volume [kg] Water absorption ability [weight- %] Water content [weight- %] Content of aggregate, adjusted for water content [kg] Adjusted mixing water of aggregate [l]

Figure 2. Formula for paper based cement mortar with 50 volume % paper fibres and 50 volume % sand.

Appendix 11 Page 1 of 1

Slump dependency on water content in paper based cement mortar Slump dependency on the water content Pf/Sa 75/25 water content pr. target Adjusted target water need Measured water added [l] [kg/target] [l] [kg/m3] slump [mm] 1,61 7,00 230 0 1,00 2,61 8,00 326 11 0,25 2,86 8,25 347 10 0,50 3,36 8,75 384 12 0,50 3,86 9,25 417 5 0,25 4,11 9,50 433 2,5 0,25 4,36 9,75 447 5 0,50 4,86 10,25 474 8 0,50 5,36 10,75 499 8 0,00 5,36 10,75 499 10 0,50 5,86 11,25 521 11 0,50 6,36 11,75 541 14 0,50 6,86 12,25 560 17 0,50 7,36 12,75 577 21 0,50 7,86 13,25 593 24 0,25 8,11 13,50 601 33 0,25 8,36 13,75 608 36 0,25 8,61 14,00 615 42 0,25 8,86 14,25 622 45 0,50 9,36 14,75 635 51 0,50 9,86 15,25 647 66 Figure 1. slump dependency on water content in paper based cement mortar with 75 volume % paper fibres and 25 volume % sand. Slump dependency on the water content Pf/Sa 50/50 water content pr. target Adjusted target water need Measured water added [l] [kg/target] [l] [kg/m3] slump [mm] 1,61 7,00 230 8 1,00 2,61 8,00 326 5 0,50 3,11 8,50 366 9 0,50 3,61 9,00 401 9 0,50 4,11 9,50 433 9 0,50 4,61 10,00 461 11 0,50 5,11 10,50 487 16 0,50 5,61 11,00 510 22 0,50 6,11 11,50 531 42 0,25 6,36 11,75 541 49 0,25 6,61 12,00 551 56 0,25 6,86 12,25 560 62 0,25 7,11 12,50 569 72 Figure 2. slump dependency on water content in paper based cement mortar with 50 volume % paper fibres and 50 volume % sand.

Appendix 12 Page 1 of 4

Appendix 12.1 CEMCEL formula Specifications Sought water need [kg/m3]; Sought w/c - ratio [-]; Sought volumen- % of sand in aggregate Volumen- % of stones in aggregate Volumen- % of waste paper in aggregate

290 1,00 50 31 19

Mortar proportioning

Cement Water Air Sand Stone Waste paper

Density in s.s.dMass kg/m3 kg/m3 3100 1000 0 2650 2650 1122

Mortar Control

2011

Volume m3/m3 0,094 0,290 0,010 0,303 0,188 0,115

290 290 0 804 498 129 2011

1 100,00%

Mortar formula

Cement Water Air Sand Stone Waste paper

Unadjusted Mass Volume kg/target vol. l/target vol. 2,90 2,90 0,00 8,04 4,98 1,29

Total

20

0,94 2,90 0,10 3,03 1,88 1,15

Target vol. 10,00 Litre Adjusted Adjusted mass Adjusted mass Adjusted Volume Adjusted Volume kg/target vol. % of total l/target vol. % of total 2,90 14 0,94 9 3,77 19 3,77 37 1 0,00 0 0,10 8,04 40 3,03 30 19 4,98 25 1,88 0,42 2 0,37 3,7

10

20,11

100

10,09

Adjustment for moisture content in aggregate Sand Content of aggregate in s.s.d. state in target volume [kg] Water absorption ability [weight- %] Water content [weight- %] Content of aggregate, adjusted for water content [kg] Adjusted mixing water of aggregate [l]

Stone 8,04 2 2 8,04 0,00

Paper pulp 4,98 2 2 4,98 0,00

1,29 235 8,69 0,42 0,87

100

Appendix 12 Page 2 of 4

Appendix 12.2 Design sketch for CEMCEL bricks formwork Primary brick, dimensions 22 cm x 10 cm x 7 cm. Measures are in millimeters.

Appendix 12 Page 3 of 4

Brick for compression strength testing

Figure 1. Compression setup for the compression strength specimens. Top left, a mortar is being poured into a double cylinder. After compression, the mortar will have a height of 200 mm, which is required in the compression strength testing. The amount of necessary excessive mortar prior to compression is derived in the report. Top right, compression ready to begin, note the special plunger, produced in the workshop at the Faculty of Civil Engineering, Technical University of Denmark, design drawing in Figure 2. Bottom left, the assembly piece between the two cylinders being produced in the workshop. Bottom right, the compression level is set so the mortar will give off free water exactly at the time when the compression is ended.

Appendix 12 Page 4 of 4

Figure 2. Design drawing for compression plunger. Measures in millimeters.

Appendix 13 Page 1 of 1

Density and porosity results Phase 1 P4-1 P4-2

m50 [g]

Phase 2 P4-1 P4-2

m150 [g]

607,58 595,80

601,00 589,21

muw [g] 369,87 362,90

muw [g] 370,40 363,07

mssd [g] 729,50 717,56

mssd [g] 729,24 718,06

3

V [m ] 0,0003603 0,0003553 3

V [m ]

3

Vo [m ] 0,00012214 0,00012198 Average 3

Vo [m ]

3

po

ρd [kg/m ] 0,339 0,343 34,1%

po

1686 1677 1682 3

ρd [kg/m ]

3

ρs [kg/m ]

3

ρssd [kg/m ]

2551 2554 2552 3

ρs [kg/m ]

2025 2020 2022 3

ρssd [kg/m ]

0,0003595 0,000128471 0,357 1672 2602 0,0003556 0,000129082 0,363 1657 2601 Average 36,0% 1664 2601 Figure 1. Determination of the open porosity, the dry density, the solid density and the surface saturated density for the brick.

2029 2019 2024

Appendix 14 Page 1 of 2

Capillary suction results 2

Specimen Width [mm] Depth [mm] Height [mm] Area [m ] m0 [g] Phase 1, P4-3 51,5 69,5 100,2 0,0036 590,34 Phase 1, P4-4 51,5 69,8 100,3 0,0036 585,49 51,64 69,32 100,38 0,0036 583,94 Phase 2, P4-3 51,58 69,85 100,4 0,0036 579,53 Phase 2, P4-4 Figure 1. Dimensions and dry mass for the specimens after conditioning, 50 °C for phase 1 and 105 °C for phase 2. time t [min] 29-01-09 12:40 29-01-09 12:41 29-01-09 12:42 29-01-09 12:44 29-01-09 12:48 29-01-09 12:56 29-01-09 13:12 29-01-09 13:40 29-01-09 14:40 29-01-09 16:30 30-01-09 09:45 30-01-09 15:00 02-02-09 07:50 02-02-09 16:20 03-02-09 11:50 03-02-09 15:20 04-02-09 08:35

t½ [s½] 0 1 2 4 8 16 32 60 120 230 1265 1580 5470 5980 7150 7360 8395

mt [g] 0,00 7,75 10,95 15,49 21,91 30,98 43,82 60,00 84,85 117,47 275,50 307,90 572,89 599,00 654,98 664,53 709,72

Phase 1, P4-3 Phase 1, P4-4 Q [kg/m2] Q [kg/m2 ] mt [g] 590,34 0,00 585,49 0,00 594,32 1,11 589 0,98 595,66 1,49 590,34 1,35 596,96 1,85 592,01 1,81 598,74 2,35 593,91 2,34 601,20 3,03 596,54 3,07 603,74 3,74 599,24 3,83 607,00 4,65 602,68 4,78 611,32 5,86 607,6 6,15 616,74 7,38 613,5 7,79 642,94 14,70 640,76 15,38 647,94 16,09 645,34 16,65 680,72 25,25 676,18 25,23 682,12 25,64 677,12 25,49 683,90 26,14 678,66 25,92 683,98 26,16 678,78 25,95 684,60 26,34 679,2 26,07

Figure 2. Weight and absorbed water by capillary suction for specimens in phase 1. Phase 2, P4-3 Phase 2, P4-4 ½ ½ 2 [s ] ] t Q [kg/m Q [kg/m2] mt [g] mt [g] time t [min] 16-02-09 09:29 0 0,00 583,94 0,00 579,53 0,00 16-02-09 09:30 1 7,75 587,47 0,99 582,7 0,88 16-02-09 09:31 2 10,95 588,50 1,27 583,89 1,21 16-02-09 09:33 4 15,49 589,52 1,56 585,32 1,61 16-02-09 09:37 8 21,91 591,10 2,00 587,2 2,13 16-02-09 09:45 16 30,98 592,80 2,48 589,27 2,70 16-02-09 10:01 32 43,82 595,08 3,11 591,97 3,45 16-02-09 10:31 62 60,99 597,82 3,88 594,99 4,29 16-02-09 11:28 119 84,50 601,66 4,95 599,03 5,41 16-02-09 13:31 242 120,50 605,92 6,14 603,34 6,61 16-02-09 17:54 505 174,07 611,88 7,81 609,6 8,35 17-02-09 10:10 1481 298,09 622,54 10,78 620 11,23 17-02-09 16:50 1881 335,95 625,22 11,53 622,68 11,98 18-02-09 10:00 2911 417,92 630,68 13,06 627,92 13,43 18-02-09 14:10 3161 435,50 631,54 13,30 628,82 13,68 19-02-09 10:30 4381 512,70 635,52 14,41 632,64 14,74 20-02-09 14:15 6046 602,30 640,44 15,78 637,56 16,11 23-02-09 13:15 10306 786,36 648,36 18,00 645,44 18,29 24-02-09 12:00 11671 836,82 650,38 18,56 647,38 18,83 25-02-09 11:00 13051 884,91 651,90 18,98 648,88 19,25 Figure 3. Weight and absorbed water by capillary suction for specimens in phase 2.

Appendix 14 Page 2 of 2 Capillary suction, phase 1 30,00

Phase 1, P4‐3

Q [kg/m2]

25,00

20,00 Phase 1, P4‐4 15,00 Upper limit 10,00 Lower limit

5,00

0,00 0

50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 t 1/2 [s1/2 ]

Figure 4. Derivation of Qkap and tkap1/2. The upper limit is derived by adding a trendline for the two last points. The lower limit is derived by adding a trendline for the points for 1 min – 16 min. The method is imprecise, because the slope of the limits is hard to determine and the results are dependent on the slope. Capillary suction, phase 2 20,00

Phase 2, P4‐3

Q [kg/m2]

15,00 Phase 2, P4‐4 10,00 Upper limit 5,00 Lower limit

0,00 0

100

200

300

400

500

600

700

800

900

1000

t 1/2 [s1/2]

tkap1/2.

Figure 5. Derivation of Qkap and The upper limit is derived by adding a trendline for the two last points. The lower limit is derived by adding a trendline for the points for 1 min – 16 min. The method is imprecise, because the slope of the limits is hard to determine and the results are dependent on the slope. 2 ½ 2 ½ ½ Q kap [kg/m ] tkap [s ] k [kg/(m *s )] m [10^6*s/m2] På Phase 1 24,5 200 0,123 3,98 0,26 Phase 2 13 165 0,079 2,70 0,19 Average 0,101 3,34 0,23 Figure 6. Determination of the absorption coefficient, resistance coefficient and the open porosity for phase 1 and phase 2.

Appendix 15 Page 1 of 3

Thermal conductivity logging data

Figure 1. Logging data, testing P3-1

Figure 2. Logging data, testing P3-2

Appendix 15 Page 2 of 3

Figure 3. Logging data, testing P3-3

Figure 4. Logging data, testing P3-4

Appendix 15 Page 3 of 3

Figure 5. Logging data, testing P3-5

Appendix 16 Page 1 of 1

Thermal conductivity calculations and results Readings P3-1 P3-2 P3-3 Red marker reading [%] 9,80% 23,80% 38,80% 100 % reading equals [mV] 5,00 2,00 1,00 u [mV] (divided with the number of points in the thermal column) 0,10 0,10 0,08 Blue marker reading(Voltage over the heating plate) 69,30% 69,00% 68,90% 5,00 5,00 5,00 100 % reading equals [V] 3,465 3,45 3,445 U [V] (Voltage over the heating plate, calculated) 3,500 3,470 3,472 U [V] (Voltage over the heating plate, read) 0,484 0,480 0,479 P [W] (Effect in the heating plate, calculated) Tvarm [째C] 14 13,7 18,8 Tkold [째C] 11,7 11,6 17 11,7 11,6 17,0 Tref [째C](Reference temperature) Tm [째C] (calculated) 13,0 12,8 18,0 delta T [K] (calculated) 2,47 2,40 1,93 Height of the specimen [m] 0,07305 0,07305 0,07305 2 0,0256 0,0256 0,0256 Heating plate area (0,16*0,16) [m ] 0,560 0,571 0,707 Thermal conductivity [W/mK] 0,566 Thermal conductivity, average [W/mK] 0,008 Thermal conductivity, standard deviation [W/mK] Figure 1. Data sheet and calculations of thermal conductivity average and distribution for the paper based brick.

P3-4 72,10% 1,00 0,14 49,00% 10,00 4,9 4,938 0,968 21,4 18 18,0 19,9 3,58 0,07305 0,0256 0,772 0,739 0,046

P3-5 65,50% 1,00 0,13 69,50% 5,00 3,475 3,504 0,487 20,5 17,6 17,6 19,3 3,25 0,07305 0,0256 0,42706 Overall 0,427 0,608 0,135

12606 Specimen weight after testing, Pstart ., [g] Weight after drying at 105 degrees celcius, P0., [g] 10587,3 Water content, u, after testing, [%] 0,191 Dry density [kg/m3] 1607 Figure 2, data sheet for calculating water content and dry density for the testing specimens.

12606 10587,3 0,191 1607

10780,2 10587,3 0,018 1607

12606 10587,3 0,191 1607

12606 10587,3 0,191 1607

Appendix 17 Page 1 of 1

Equilibrium water content at the different humidity levels Water content #1 Dry mass m0, after the experiment [g]: Mass of petri bowl [g]

#2

#3

Average

12,0 60,747

11,4 48,276

15,9 50,168

Equilibrium state: Fresh Specimens equlibrium-mass [g] : water content, u [-]:

13,919 15,67%

13,135 15,38%

18,192 14,40%

15,15%

Equilibrium state: D85 Specimens equlibrium-mass [g] : water content, u [-]:

12,386 2,93%

11,750 3,22%

16,352 2,83%

2,99%

Equilibrium state: D50 Specimens equlibrium-mass [g] : water content, u [-]:

12,171 1,15%

11,524 1,23%

16,064 1,02%

1,13%

Equilibrium state: A85 Specimens equlibrium-mass [g] : water content, u [-]:

12,345 2,59%

11,718 2,93%

16,329 2,69%

2,74%

Appendix 18 Page 1 of 1

Moisture M re elated defo ormation 0,02 0,01

80

START

Time [h hours]

0 0

00 10

200

300

40 00

500

600

70 00

800

00 1.00 60

‐ ‐0,02 ‐ ‐0,03 ‐ ‐0,04

M Maximum deformation

40

STOP

‐ ‐0,05

85‐ 50% RH

Hyysteresis effecct

20

‐ ‐0,06 ‐ ‐0,07 ‐ ‐0,08

0

‐ ‐0,09 ‐0,1

50‐ 85% RH

Fresh ‐ 85% RH

‐ ‐0,01

900

‐20

Average Temp RH

Figure 1 Average A deformation in percentage on the left vertical axiis. Temperature and d relative humidity on o the right vertical axis. The intervalss are noted outside the graph area, from STAR RT to STOP. The waater content is noted d in the bottom for each e equilibrium sta ate. The hysteresis effect e infliction on the t deformation is iindicated by a yellow arrow. The total moistu ure deformation is iindicated by a lightt blue arrow.

Appendix 19 Page 1 of 2

Summary of discussion with Per Goltermann Subject How to perform testing for determination of working curve for paper based bricks.

Time and place 28- January, 2008. Technical University of Denmark (DTU),

Participants • •

Docent Peter, Goltermann (PG), DTU Civil Engineering Mads Prange Kristiansen (MPK), project holder, student DTU Civil Engineering.

Discussion MPK – Brief introduction to project. Working curve wanted instead of just compression strength. MPK – Which standard to be used? The following standards have been investigated: DS/EN 772-1, DS 423.23, DS 423.25, ISO 12570, EN 1352:196 D/E/F. PG – No standards exists for working curves, only for E-module and compression strength. PG knows how it should be performed though. MPK – How should they be conditioned? PG – Freshly cured as described by MPK (in 100% RH and 32 degrees Celsius), no drying. This is representative to the conditions sought in India, and the bricks can be presumed to gain strength over time from drying and further hydration, making the freshly cured condition a “lowest case” for the brick compression strength. MPK – Don’t want to use external deformation instruments, can the Instron 6025 cylinder movement be used instead? PG – Yes, by using a piece of paper between the specimen and Instron 6025. The paper will reveal if the full surface is not in contact, plus it will distribute the load.

Agreed Method Specimen is placed in Instron 6025 with a piece of ordinary printing paper between the specimen and Instron on both sides. In the following, the method is described. The numbers refers to the numbers in Figure 1. MPK/PG: 1. Load till fc25%=25 %* 3.7 MPa ≈1.0 MPa or approximately 8 kN. This removes instrumental tolerances and specimen surface tolerances, and compresses the paper. 2. Unload to 0.3 MPa or approximately 2.5 kN. At this point, the paper remains compressed, but the tolerances remains removed. At this point, the strain is balanced to zero in the user interface, which moves the graph left till it intersects the y-axis at 0.3 MPa. 3. Reset the strain-axis to zero to move the graph. 4. Load to failure with 0.05MPa/s, according to EN CEN/TC 177. After the specimen fails, fragments are weighted, dried and weighted again to determine the water content.

Appendix 19 Page 2 of 2 Results should be plotted together as Ďƒ/fc in order to see how the results correspond to

each other.

Figure 1. Numbers refers to the description above. Left, Point 1) to 6). Right, point 7).

Appendix 20 Page 1 of 4

Formulas for sensitivity analysis Specifications Sought water need [kg/m3]; Sought w/c - ratio [-]; Sought volumen- % of sand in aggregate Volumen- % of stones in aggregate Volumen- % of waste paper in aggregate

290 1,10 50 31 19

Mortar proportioning

Cement Water Air Sand Stone Waste paper

Density in s.s.dMass kg/m3 kg/m3 3100 1000 0 2650 2650 1122

Mortar Control

2005

Volume m3/m3 0,085 0,290 0,010 0,307 0,191 0,117

264 290 0 815 505 131 2005

1 100,00%

Mortar formula

Cement Water Air Sand Stone Waste paper

Unadjusted Mass Volume kg/target vol. l/target vol. 2,64 2,90 0,00 8,15 5,05 1,31

Total

20

0,85 2,90 0,10 3,07 1,91 1,17

Target vol. 10,00 Litre Adjusted Adjusted mass Adjusted mass Adjusted Volume Adjusted Volume kg/target vol. % of total l/target vol. % of total 2,64 13 0,85 8 3,79 19 3,79 37 1 0,00 0 0,10 8,15 41 3,07 30 19 5,05 25 1,91 0,43 2 0,38 4

10

20,05

100

10,10

Adjustment for moisture content in aggregate Sand Content of aggregate in s.s.d. state in target volume [kg] Water absorption ability [weight- %] Water content [weight- %] Content of aggregate, adjusted for water content [kg] Adjusted mixing water of aggregate [l]

Figure 1. Formula for tertiary testing with w/c=1,1

Stone 8,15 2 2 8,15 0,00

Paper pulp 5,05 2 2 5,05 0,00

1,31 235 8,69 0,43 0,89

100

Appendix 20 Page 2 of 4 Specifications Sought water need [kg/m3]; Sought w/c - ratio [-]; Sought volumen- % of sand in aggregate Volumen- % of stones in aggregate Volumen- % of waste paper in aggregate

290 1,20 50 31 19

Mortar proportioning

Cement Water Air Sand Stone Waste paper

Density in s.s.dMass kg/m3 kg/m3 3100 1000 0 2650 2650 1122

Mortar Control

1999

Volume m3/m3 0,078 0,290 0,010 0,311 0,193 0,118

242 290 0 824 511 133 1999

1 100,00%

Mortar formula

Cement Water Air Sand Stone Waste paper

Unadjusted Mass Volume kg/target vol. l/target vol. 2,42 2,90 0,00 8,24 5,11 1,33

Total

20

0,78 2,90 0,10 3,11 1,93 1,18

Target vol. 10,00 Litre Adjusted Adjusted mass Adjusted mass Adjusted Volume Adjusted Volume kg/target vol. % of total l/target vol. % of total 2,42 12 0,78 8 3,80 19 3,80 38 1 0,00 0 0,10 8,24 41 3,11 31 19 5,11 26 1,93 0,43 2 0,38 4

10

19,99

100

10,10

Adjustment for moisture content in aggregate Sand Content of aggregate in s.s.d. state in target volume [kg] Water absorption ability [weight- %] Water content [weight- %] Content of aggregate, adjusted for water content [kg] Adjusted mixing water of aggregate [l]

Figure 2. Formula for tertiary testing with w/c=1,2

Stone 8,24 2 2 8,24 0,00

Paper pulp 5,11 2 2 5,11 0,00

1,33 235 8,69 0,43 0,90

100

Appendix 20 Page 3 of 4 Specifications Sought water need [kg/m3]; Sought w/c - ratio [-]; Sought volumen- % of sand in aggregate Volumen- % of stones in aggregate Volumen- % of waste paper in aggregate

290 1,30 50 31 19

Mortar proportioning

Cement Water Air Sand Stone Waste paper

Density in s.s.dMass kg/m3 kg/m3 3100 1000 0 2650 2650 1122

Mortar Control

1995

Volume m3/m3 0,072 0,290 0,010 0,314 0,195 0,119

223 290 0 832 516 134 1995

1 100,00%

Mortar formula

Cement Water Air Sand Stone Waste paper

Unadjusted Mass Volume kg/target vol. l/target vol. 2,23 2,90 0,00 8,32 5,16 1,34

Total

20

0,72 2,90 0,10 3,14 1,95 1,19

Target vol. 10,00 Litre Adjusted Adjusted mass Adjusted mass Adjusted Volume Adjusted Volume kg/target vol. % of total l/target vol. % of total 2,23 11 0,72 7 3,80 19 3,80 38 1 0,00 0 0,10 8,32 42 3,14 31 19 5,16 26 1,95 0,43 2 0,39 4

10

19,95

100

10,10

Adjustment for moisture content in aggregate Sand Content of aggregate in s.s.d. state in target volume [kg] Water absorption ability [weight- %] Water content [weight- %] Content of aggregate, adjusted for water content [kg] Adjusted mixing water of aggregate [l]

Figure 3. Formula for tertiary testing with w/c=1,3

Stone 8,32 2 2 8,32 0,00

Paper pulp 5,16 2 2 5,16 0,00

1,34 235 8,69 0,43 0,90

100

Appendix 20 Page 4 of 4 Specifications Sought water need [kg/m3]; Sought w/c - ratio [-]; Sought volumen- % of sand in aggregate Volumen- % of stones in aggregate Volumen- % of waste paper in aggregate

290 1,40 50 31 19

Mortar proportioning

Cement Water Air Sand Stone Waste paper

Density in s.s.dMass kg/m3 kg/m3 3100 1000 0 2650 2650 1122

Mortar Control

1991

Volume m3/m3 0,067 0,290 0,010 0,317 0,196 0,120

207 290 0 839 520 135 1991

1 100,00%

Mortar formula

Cement Water Air Sand Stone Waste paper

Unadjusted Mass Volume kg/target vol. l/target vol. 2,07 2,90 0,00 8,39 5,20 1,35

Total

20

0,67 2,90 0,10 3,17 1,96 1,20

Target vol. 10,00 Litre Adjusted Adjusted mass Adjusted mass Adjusted Volume Adjusted Volume kg/target vol. % of total l/target vol. % of total 2,07 10 0,67 7 3,81 19 3,81 38 1 0,00 0 0,10 8,39 42 3,17 31 19 5,20 26 1,96 0,44 2 0,39 4

10

19,91

100

10,10

Adjustment for moisture content in aggregate Sand Content of aggregate in s.s.d. state in target volume [kg] Water absorption ability [weight- %] Water content [weight- %] Content of aggregate, adjusted for water content [kg] Adjusted mixing water of aggregate [l]

Figure 4. Formula for tertiary testing with w/c=1,4

Stone 8,39 2 2 8,39 0,00

Paper pulp 5,20 2 2 5,20 0,00

1,35 235 8,69 0,44 0,91

100

Appendix 21 Page 1 of 2

Stress/strain- relation curves for primary testing Stress/Strain

stress [MPa] 4 3,5 3 2,5 2

P1-1

1,5 1 0,5 0 0

2

4

6

8

10

Strain [0/00]

Figure 1. Logging data, testing P1-1

Stress/Strain

stress [MPa] 4 3,5 3 2,5 2

P1-2

1,5 1 0,5 0 0

2

4

Figure 2. Logging data, testing P1-2

6

8

10

Strain [0/00]

Appendix 21 Page 2 of 2

Stress/Strain

stress [MPa] 4,5 4 3,5 3 2,5

P1-3

2 1,5 1 0,5 0 0

2

4

6

8

10

Strain [0/00]

Figure 3. Logging data, testing P1-3

Stress/Strain

stress [MPa] 4 3,5 3 2,5 2

P1-4

1,5 1 0,5 0 0

10

20

30

Figure 4. Logging data, testing P1-4

40

50

60

70

Strain [0/00]

Appendix 22 Page 1 of 1

Stress/strain- relation curves for secondary and tertiary testing Users are referred to the excel-file: Excel sheets/ Calculations_Materialproperties.xlsx In the enclosed CD-rom.

Appendix 23 Page 1 of 3

Product sheet, Novozym 51003

Appendix 23 Page 2 of 3

Appendix 23 Page 3 of 3

Paper Fibre Based Bricks for Low Cost Housing in Developing Countries Annex 1, Novozym 51003 Mads Prange Kristiansen

MSc Thesis project in Civil Engineering, 2009

s032486

For information on Annex1_Novozym 51003, please contact Restart SMBA. Contact info on the webpage www.restart.nu or by email pw@restart.nu or mpk@restart.nu

Paper Fibre Based Bricks for Low Cost Housing in Developing Countries Annex 2, Field study Mads Prange Kristiansen

MSc Thesis project in Civil Engineering, 2009

s032486

1 Table of contents 1

Table of contents ..................................................................................................... 2

2

Background and purpose ........................................................................................ 3

3

Visiting Hyderabad, state of Andhra Pradesh ......................................................... 4 3.1 Muffakham Jah College of Engineering & Technology ................................. 4 3.2 Contractors Development Institute.................................................................. 6 3.2.1 Introduction and general discussion......................................................... 6 3.2.2

General brick development in India ......................................................... 6

3.3 Rasoolpura slum dwellings ............................................................................. 8 3.4 Army Dental College Landfill....................................................................... 11 3.5 National Institute of Rural Development ...................................................... 13 3.6 Sieving curve experiment .............................................................................. 14 4 Visiting Auroville, state of Tamil Nadu ............................................................... 15 4.1 4.2

Volunteering in road construction work and masonry work using mud bricks 16 Architectural study of Auroville buildings.................................................... 17

Page 2 of 18

2 Background and purpose

On Monday the 29th of September 2008, Engineers Without Borders Denmark held a seminar at the Technical University of Denmark. Professor Ali Ansari was the main speaker, telling about the work of Engineers Without Borders India. After the meeting, during informal talking and coffee, Professor Ali Ansari suggested for me to come and visit Hyderabad. This would strengthen not only the project itself, but also my personal perception of the problems. In Rasoolpura After successfully applying for scholarships and private funding, the field study became realistic and was planned in February 2009 to be conducted in March 2009. The field study was divided in two parts of roughly a week’s duration each. One week in Hyderabad in the state of Andhra Pradesh and one week in the eco community Auroville, state of Tamil Nadu. The purpose of the visit to Hyderabad was to test some of the assumptions made in the project, such as the waste disposal problem’s actuality or the actual state of the buildings in the Rasoolpura slum. The visit to Auroville was of more undefined character. The purpose was to gain knowledge of sustainable solutions, and investigate existing building techniques that are presently in use.

Front-page picture: Stacked mud bricks for building project, Hyderabad, India. Photograph is taken by Mads Prange Kristiansen.

Page 3 of 18

3 Visiting Hyderabad, state of Andhra Pradesh

The city of Hyderabad is placed centrally in India in the state of Andhra Pradesh, Figure 1. Hyderabad is the capital city and most populous city of Andhra Pradesh. It has an estimated population of about 7 million. Hyderabad is known for its rich history, culture and architecture representing its unique character as a meeting point for North and South India, and also its multilingual culture, geographically, culturally and intellectually. Hyderabad is today one of the fastest developing cities in India and a modern hub of Information Technology, Information Technology Enabled Service (such as call centres for large companies service departments) and Biotechnology. The people here are called Hyderabadis. The city is regarded as a blend of traditionality with modernity [22].

Figure 1. Satellite photo with city names and major roads. Yellow dot is Hyderabad. Source, Google Maps.

3.1 Muffakham Jah College of Engineering & Technology Already before arrival, student members of EWB India from MJCET had been of great help in planning my visit. A guest house in walking distance from the MJCET had been booked and I was picked up the morning after my arrival by the final year students, Waheed, Kaleem, Zafar and Arshad. Upon arrival at the university, I had a meeting with Professor Ali Ansari. Together with him, the overall schedule for my visit in Hyderabad was put together, Table 1.

Page 4 of 18

Date 18th 19th

Activity  Visit the Muffakham Jah College of Engineering & Technology.

21st

    

Visit the Contractors Development Institute Visit the Godrej Building, CIIA Building centre Visit the Rasoolpura slum dwellings Visit the Army Dental College Landfill Visit the National Institute of Rural Development

22nd

Informal sightseeing in Hyderabad.

23rd

Sieving curve experiment the Civil Engineering workshop at the Muffakham Jah College of Engineering & Technology. Train departure to Chennai

20th

Table 1. Activity schedule for the visit in Hyderabad from 18 th to the 23rd of March 2009.

From professor Ali Ansari’s many personal friends and acquaintances at the different institutions, I was given contact information key persons in all of the scheduled visits, making my stay in Hyderabad effective and educational. The students are doing their final project in a group of 6. The project is to design and plan a six storeys building. When I arrived, they were forming cubic specimens of steel fibre reinforced concrete for compression strength testing, Figure 2.

Figure 2, Workshop at the Faculty of Civil Engineering. The students are mixing mortar for compression strength testing of steel fiber reinforced concrete.

While in the workshop, arrangements was made in order for me to perform a sieving curve experiment on locally obtained riverbed sand used in the housings of the Rasoolpura slum. The experiment is referenced in section 3.6.

Page 5 of 18

3.2 Contractors Development Institute 3.2.1 Introduction and general discussion

The visit at Contractors Development Institute (CDI) showed to be education in many more ways than expected. The facility itself was quite impressive compared to other educational institutions in Hyderabad. Generally, CDI holds short term seminars, summer schools etc. for students from all universities. At the time of my visit, students were finishing a 3 day seminar on construction management. Professor K. Purushotham Reddy was the one to greet me welcome. Professor K. P. Reddy is educated in Political Science, and present he is basically an activist. He holds an administrating post at the CDI. His competencies secures that all kinds of social issues is considered when constructional matters are determined.

Figure 3. Left, Hosts and visitors. From the left, student Arshad, me, student Keleem, Professor K. P. Reddy, Mr. Farooq Ali Khan from Chicago and student Waheed. Right, meeting at Professor K.P. Reddy’s office.

After I had briefly explained the purpose of my visit to Hyderabad, the subject changed to the strength of India. Not in terms of finances, military or politics, but in terms of natural resources. According to Professor K. P. Reddy, the only natural resource that India can pride itself of is their “youngsters”, pointing to my companions from MJCET. Apart from them, India has consumed so many of its natural resources that the resources/capita- ratio in India is one of the worlds lowest. Therefore the youngsters must travel abroad, work hard and transfer money back to India. Hence international interaction is of essence, and Professor K. P. Reddy therefore told me that they would provide any information wanted and share all knowledge with me. Considering this, I asked them for directions to Hyderabad’s primary land fill. The professor answered without hesitation that I should go to the land fill past the Army Dental College, and added “During your visit here in Hyderabad, you will experience great things of India. In that place, you will experience the very worst”. The visit is resumed in section 3.4.

3.2.2 General brick development in India

The following is resumed from the broad discussion on brick development, and represents the general opinion of Professor K. P. Reddy. In the ancient India, 4000 years ago, India made mud bricks so lightweight they could float. Today, burned mud bricks carry 3 storey houses and lasts for more than 100 years. In the villages, mud bricks are compressed and dried only in the sun, having a lifetime of 30+ years. These houses were built with such thick walls, that the indoor climate remained cool even on the hottest days. Page 6 of 18

In modern times, the preference has tilted towards concrete. In high rise structures, the superior strength of concrete is a necessity. However, concrete bricks are also used in double and single storey buildings, where mud bricks have more than sufficient strength and much lower cost. This unnecessary use of the high energy embodied cement is founded in psychological reasons, as modern contractors are reluctant to rely on the ancient mud brick techniques, though they are cheaper and superior in many ways.

Page 7 of 18

3.3 Rasoolpura slum dwellings The Rasoolpura slum is approx. 1000 meters long and 500 meters wide. It is placed next to the old airport of Hyderabad, which is now used only by the military. The slum is pictured in Figure 4.

Figure 4. Satellite photo of the Rasoolpura slum next to the old airport of Hyderabad. Source, Google Maps.

The first major assumption in the main project is that the quality of existing building materials in the Rasoolpura slum is very poor. This is investigated in the following. I had the major advantage that the students from MJCET knew a resident there named Moin. Moin was my guide during my visit. What strikes one when visiting Rasoolpura is that the general conditions are not as expected. There are obvious problems, of which some will be addressed in the following. But the general impression is that conditions are better than expected. In fact, Rasoolpura is a fairly developed community with many internal functions like schools, a locally elected mayor etc. As described in the project case in the main report, the slum dwellers have small jobs and a household makes enough income to make a living. Relocation was once offered to a newly build housing area outside the city centre, but the slum dwellers declined and did not move to the allocated homes. This was because the relocation package did not involve alternative jobs to their existing jobs in the city centre. The general quality of the building materials used in Rasoolpura varies greatly, Figure 5. The houses in poorest condition have roofs made from plastic bags and different plate materials. The walls will also be made from plastic sheets, wooden boards etc. However, most of the houses have brick walls, made from either burned or sundried mud bricks, or cement bricks. The roofing of the better houses is made from cement fiber boards, similar to those used in western countries.

Page 8 of 18

Figure 5. Left, lower extreme for the quality of constructions. Right, building process of the upper extreme for the quality of constructions.

The masonry method used is similar to a western double thickness brick wall. Bricks are produced in large quantities at production sites in the suburbs around the city. In general, the masonries master many different methods and bonds.

Figure 6. Left, burned mud bricks delivered in Rasoolpura from the manufacturer. Right, close up of the bond.

Though the buildings in Rasoolpura are generally of fair quality, the community faces other challenges. A German master student, Pierre-Jacques Frank from Universit채t Karlsruhe did a MSc on the sewage conditions in Rasoolpura. These are in extremely poor condition. Basically, all waste water from toilets (black water), kitchens (grey water) etc run into one single channel that runs through the community, Figure 7. Stray dogs and goats walk in the channel, searching for food scraps. At all times, sewages around the community are overflowing because the system is overburdened. This causes great health risks to the residents. The waste water cause a severe threat to the supply of fresh water, because the extremely polluted water from the leaking sewage system interacts with the ground water.

Page 9 of 18

Figure 7. Left, the central sewage channel handling all the wastewater of Rasoolpura. Right, black water running in the streets from overflowing sewages.

The major reason why the sewage and other problems are not being effectively addressed is the complexity and inefficiency of the Hyderabad bureaucracy. One commune is responsible for the land of Rasoolpura, while another commune is responsible for the sewage. This makes the political process of a modern sewage system practically impossible. However, Rasoolpura also has many stories of success. Thanks to many devoted volunteers, passionate dwellers and a variety of Non Governmental Organisations, Rasoolpura offers schooling to the kids of the community, Figure 8. There is a free school, where kids learn Hindi, English, math etc. For the more fortunate families, there is also a private school. For a monthly fee of 70 Rupees, the equivalent of 1euro, parents can send their kids in a full ten year school.

Figure 8. Left, kids at the free school. Right, kids in the private school.

Page 10 of 18

3.4 Army Dental College Landfill The second major assumption in the main project is that Hyderabad has a tremendous problem with waste disposal. A considerable part of this waste was assumed to be easily obtained paper. Therefore the local landfill was to be visited. However, the landfills are naturally not something India is particularly proud of. They are not mapped, they are not sign posted, they are placed far from the city centre in deserted areas, and anyone but the garbage trucks and the official workers are not supposed to go there. Considering this, it was a challenge getting a visit planned. As described in section 3.2.1, Professor K. P. Reddy explained me that I would find the landfill past the Army Dental College (ADC). Moin, who had guided me in my visit in Rasoolpura, offered to take me there on his motorbike. This was a perfect solution, as he knew the location of the ADC, and naturally spoke perfect Hindi. As we drove close to the ADC, this proved to be of great help. Policemen stopped us, asking for the purpose of us going further. He calmly replied that I was a European visitor for the ADC. They immediately let us through. The first thing that hits you when entering the landfill is the smell. The waste is continuously set on fire, and the smell of burning plastics and all sorts of other unsorted waste is thick. Figure 9 shows the rag pickers, as they are searching the smouldering waste.

Figure 9. Left, from one waste hill, rag pickers can be spotted on another waste hill. Right, rag pickers searching the nearby waste for recyclable materials.

Most domestic waste from Hyderabad goes here. Hyderabad has a population of more than seven million people. The trucks unload the garbage on the hill tops, then bulldozers push the waste into the land fill and it is set on fire, causing nauseating smoke continuously rising from the site. In between, when the waste is lying on the hill tops, the rag pickers are busy searching, Figure 10.

Page 11 of 18

Figure 10. The bulldozers are pushing the waste into the landfill. Rag pickers are searching for recyclable materials.

The rag pickers work there illegally, but are allowed to collect the recyclable waste. The phrase “rag pickers” is really very misplaced. In fact, they should be called “friends of the environment”, as they are the only ones performing any kind of recycling of the waste in the landfills. They live next to the landfill in conditions far worse than those in Rasoolpura, Figure 11.

Figure 11. Left, the rag pickers houses. Right, two boys returning from the landfill with full bags.

Generally, the assumption in the main report, that waste paper could be collected by rag pickers is solid. However, since the landfill is continuously burning, it has become clear that the waste paper should be collected prior to arriving to the landfill.

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3.5 National Institute of Rural Development The National Institute of Rural Development (NIRD) was established in 1999. It is established in an area of 65 acres of land with a scope to envisage for transfer of technology through demonstrations. By doing this, the vision is to increase productivity and enhancing quality of life in rural areas, hereby enabling them to move towards sustainable development. They have programmes relating to water treatment, farming, fishing, leather production, sanitation, energy, sewing production, honey production and many others. The programme most interesting to this project is a collection of 16 sample houses. From all over India, construction methods for rural houses has been investigated and the result is 16 full scale houses made from various materials, such as bamboo, wattle, stone and mud. Most interesting for the project was the mud brick constructions. The traditional mud brick house is made from a mixture of mud and hay, which is poured in a shuttering formwork on site in sections of approx. 2.5 meters width and 0.8 meters height. After sun drying, the next section is simply formed on top of the prior, and so the house progresses. The thickness of these walls is approx. 1.3 meters at the bottom and 0.75 meters at the top. The finished construction is left to cure for 7-10 days while periodically sprinkled with water. Other houses use sun dried mud bricks much similar to those in Rasoolpura. The big advantage compared to commercial bricks is that they can be produced on site and used directly at a very low cost. This technology is a perfect economical option to build cheap housing with very low embedded energy. The bricks are often used in combination with a super structure of fly ash cement based columns. However, the bricks can also be used on their own. In areas, where seismic activity is high, the mud brick houses are made circular with vertical and horizontal steel reinforcement for each meter, Figure 12.

Figure 12. Left, mud brick house with super structure in fly ash concrete based columns. Right, circular steel reinforced mud brick house, preventing the structure from collapsing during earthquakes.

Common for all the mud brick constructions is that their foundation is made from stones in order to prevent the houses from collapsing when the monsoon brings floods.

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3.6 Sieving curve experiment When visiting Rasoolpura, a sand sample was collected. This sample was dried in the sun and a sieving curve was derived using the same testing method as in the sieving curve experiment in the main report. The sieving curve is shown in Figure 13. The average particle size is derived to 0.45 mm, as shown in the sieving curve. In comparison, the sand used in the brick development at the Technical University of Denmark (DTU) had an average size of 0.40 mm. Figure 13 also shows that the particle size is uniform, compared to the sand used at DTU. Approximately 65 % of the Rasoolpura falls in the interval between 0.300 mm. and 0.600 mm. For the sand used at DTU, 35 % is in the interval between 0.250 mm and 0.500 mm. Since the average particle size of the Rasoolpura sand, 0.45 mm, and the sand used at DTU, 0.40 mm, is relatively close, the potential infliction that this has on the developed bricks is considered minor.

Sieving curve Mads Prange Kristiansen BYG*DTU

100 90

Fall through, weight %

80 70 60 50 40 30

20 10 0

0,1 0,15

0,3 Sand

0,6

1 1,18

2,36

4,75 8

10

16

Sieve width mm

32

64

100

Stones

Figure 13. Sieving curve for the sand collected in Rasoolpura.

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4 Visiting Auroville, state of Tamil Nadu

Auroville is an experimental township the state of Tamil Nadu, India near Puducherry in South India. It was founded in 1968 by Mirra Richard (since her definitive settling in India called "(The) Mother") and designed by architect Roger Anger. Auroville is meant to be a universal town where men and women of all countries are able to live in peace and progressive harmony, above all creeds, all politics and all nationalities. The purpose of Auroville is to realize human unity [22]. According to the Auroville webpage [23], "The dream of building a new city for the future on a clean slate, with the purpose of promoting research and experimentation alongside integral development, has been attracting architects and students of architecture from all over the world ever since Auroville´s inception in 1968. Not having pre-defined by-laws or being bound by the conventions of human society has allowed a multitude of expressions to manifest in the course of Auroville´s development, as natural extensions of the quest for the new." Satprem Maïni a French Aurovilian architect, the director of the Auroville Earth Institute, is representative for India and South Asia to the “UNESCO Chair Earthen Architecture, Constructive Cultures and Sustainable Development”. Satprem and other architects have won many national and international awards for their works, in and out of Auroville. Professor Ali Ansari suggested a visit to Aeroville, because all kinds of sustainable solutions in constructions and all other aspects are being tested and implemented if found to have practical utility. A Guest House was booked centrally in the community. For a further explanation on Auroville, encouragement is given to read the webpage of Auroville, www.auroville.org.

Figure 14. Satellite photo with city names and major roads. Yellow dot is Auroville. Source, Google Maps.

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4.1 Volunteering in road construction work and masonry work using mud bricks Much of the general construction work in Auroville is based on volunteering work. Additional demand is met by hiring professional contractors from outside Auroville. On the 25th of March, I volunteered in a road construction managed by the Earth Institute. By talking to the managers, I learned that there was also ongoing masonry work to be done. In the afternoon, the site was visited, and in the morning of the 26 th, I volunteered on site doing masonry work, Figure 15.

Figure 15. A local mason and I doing masonry.

The project was a terraced house for eight families. The bricks used were mud bricks, but containing 5 % of cement. By using a little cement, the bricks obtained properties equal to burned mud bricks, but could be dried in the sun and more importantly, produced on site, because burning equipment is not required. The bricks are formed in several geometries. Some with cut outs for electrical installations etc, so that cutting of the finished bricks is limited to a minimal. The production machine and stored bricks ready for being built in is shown in Figure 16.

Figure 16. Left, mud brick compression machine and one of the architects connected with the project. The machine uses only man power.

The terraced house was using an innovative cooling system that did not require any energy. The concept used a cooling well and a heat chimney, Figure 17. The system works by suction. The heat chimney is painted black. Hence, the air inside is rapidly heated and rises up, resulting in a vacuum inside the house. This sucks the air out from the intake from the cooling well. The air in the cooling well is cooled from the earth, and when it comes into the house it fall down, until it is heated up and rises up into the heat chimney where it is rapidly heated, proving further vacuum.

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Figure 17. Principal sketch of the cooling well and the heat chimney.

Based on the explained cooling system, I had a very interesting discussion on the need for insulating materials in houses in India without any cooling system. To much surprise, an architect on site proclaimed that the insulation properties of the building material are irrelevant. In fact, he claimed that they should preferably be poor. The idea is that the temperature difference between night and day is small in most of India, except from far north. Therefore, the indoor temperature in a good insulated house won’t vary much over 24 hours. And since the house is not cooled (or heated) the insulation will only delay the heating of the indoor slightly. In fact in the evening, the heat from cooking stoves etc., results in indoor temperatures higher than the outdoor temperature during night time- The exact opposite effect of the intended. Instead, the heat capacity must be lowered as much as possible to prevent a buffer effect from the sun heated walls during the day, releasing the heat during the night. Also, heating should be prevented using heat reflecting surfaces and shading. It must be emphasized, that the claim is only intended for houses with no cooling system.

4.2 Architectural study of Auroville buildings On the 27th, I cycled around Auroville looking at buildings of architectural interest. A multi storey house was build using mud bricks. Stairs and a few columns and beams was made from conventional cement, Figure 18

Figure 18. 4 storeys building build from mud bricks.

The house has a water purification system that uses plantation. The black water from toilets are first filtered in a septic tank to separate solids. Then the black water slowly Page 17 of 18

runs through a series of special plants, that uses the nutrients in the water to grow and do photosynthesis. Eventually, the water runs into a small pond, from where it is reused as grey water for flushing of toilets, to water gardens and plantations etc, Figure 19.

Figure 19. Left, rain water storage from the monsoon rain. Right, Purification system of black water using plantation filtering.

Other houses had walls that were compressed in layers, Figure 20. The method is to make a formwork of two meters width and half a meters height. The mortar is then poured into the formwork and stamped manually, each layer approx. 10 cm high after compression. When the formwork is full, the section is left to dry, and then the formwork is fixed on top of the finished section, and the process repeated. The finished wall will clearly reveal the layers, giving an interesting expression. The properties and mortar composition are similar to those of the mud bricks.

Figure 20. Layered compressed mud wall.

The architectural study in Auroville gave inspiration in general sustainable solutions, both constructional and others. Related to the project, it served as a reference to modern sustainable methods that are being used in praxis. Specifically, the mud bricks were again concluded to be the most promising building material, primarily because of its low tech and low cost level. Further, the fact that they can be produced on site, parallel to the building process with a very short production time is a great advantage. In Auroville, the mud bricks are put into an architectural context that reveal their potential, both in small houses suitable for slum areas, but also for modern multi storey houses and villas of high quality.

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