Not Just Another Brick in the Wall Improving the ecobalance of brickwork in Hamburg, Germany by Kathia Roman

Not Just Another Brick in the Wall Improving the ecobalance of brickwork in Hamburg, Germany

Submitted by: Lisa Harseim (6036736) Lucy Soares Henriques (6037260) Kathia Vanessa RomĂĄn Reina (6037082) Assignment: Final Term Paper Course: Urban Material Cycles REAP-M-202-100 Summer term 2016 Hafencity UniversitĂ¤t Hamburg Instructor: Prof. Kerstin Kuchta, Dr.-Ing.

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

TABLE OF CONTENTS I.

List of Tables

II.

List of Figures

III.

List of Abbreviations

IV.

Abstract

Facts and Figures around Bricks

1.1.

Characteristics

1.2.

Challenge

1.3.

Circular Economy

Cradle-to-Grave Analysis of Bricks

Solutions for Hamburg

3.1.

Lime Mortar

3.2.

Hempcrete

3.3.

Reclaimed Brick Wall

3.4.

Industrial Symbiosis

Conclusion

References

VI.

Annex

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

I. List of Tables Table 01

Life Cycle Assessment of Clay Brick Production

II. List of Figures Figure 01

Example of brick usage (Ard-El-Lewa, Cairo)

Figure 02

Map of Hamburg with buildings that use red clay bricks (marked in red in their faรงades)

Figure 03

Construction waste generation in Germany

Figure 04

Circular economy diagram

Figure 05

Technical circle of lime

Figure 06

Chopped hemp fibre, hempcrete block, hempcrete wall construction, hempcrete wall finish

Figure 07

Hemp worldwide current large scale production indicated by the green dots

Figure 08

Qualitative diagrammatic comparison of life cycles approached with different proposals

Figure 09

Qualitative diagrammatic representation of predicted investments during life cycle of reclaimed brick wall proposal

Figure 10

Transport of prefabricated brick walls and assembly of big block masonry using hydraulic aids.

Figure 11

Comparison of production costs of different construction types of masonry

Figure 12

Proposed industrial symbiosis partnership in Hamburg

Figure 13

Overview of positive effects of all proposals regarding sustainability criteria.

Figure 14

Expected correlation of impact and required changes in BAU of the proposals

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

III. List of Abbreviations BAU

Business as Usual

C&D

Construction and Demolition

CMU

Concrete Masonry Unit

European Commission

GHG

Greenhouse Gases

n. d.

No Date

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

IV. Abstract Clay bricks have been widely used all around the globe as construction material since 10,000 years ago (Anwar & Khitab, 2016), due to their valuable characteristics such as durability, insulation and thermal mass, low maintenance, well-known and flexible construction. â&#x20AC;&#x2039;The life cycle analysis of bricks reveals not only multiple issues regarding sustainability, such as exploitation of natural resources, land consumption and pollution, landfilling and GHG emissions alongside every phase from production over service life to demolition, but also its linearity. As a result, the high amount of invested energy and work embodied in a brick is lost at the end of its life requiring an iteration of the negative side effects. The research question guiding this paper is: "How can the ecobalance of bricks be improved, globally and in the specific context of Hamburg, regarding environmental aspects if seen through the lense of circular economy?". The general assessment of the life cycle, which phases are spread over the globe, provides an overview of the aforementioned side effects and consequences, pointing out the root of the problems and proposes conceivable solutions, e.g. wastewater treatment and improved efficiency in production, use of alternative energy sources and construction materials. In a second step, the pool of solutions is narrowed down to focus on attainable goals for Hamburg, introducing and discussing innovative solutions, namely use of lime mortar, reusing brick walls, use of Hempcrete and the practical application of Industrial Symbiosis. The results of this discussion indicates a path yet to be explored for Hamburg. Furthermore, the proposals for the specific context might be transferable and the lesson learnt from the concluded optimal combination of solutions for Hamburg might serve as a model pattern for similar climatic and economic conditions, contributing to a small step towards a more sustainable ecobalance for brickwork. Research Question: "How can the ecobalance of bricks be improved, globally and in the specific context of Hamburg, regarding environmental aspects if seen through the lense of circular economy?â&#x20AC;? Keywords: Life Cycle of Clay Bricks, Environment, Circular Economy, Industrial Symbiosis, Reused Brick Wall, Hempcrete

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

1. Facts and Figures around Bricks 1.1. Characteristics This chapter describes the main characteristics of clay bricks regarding physical features and their life-cycle in order to devise strategies for the implementation of a circular economy concept within brick production in Hamburg. Being used for centuries, clay bricks are one of the most applied materials in construction, highly due to its lasting durability, little maintenance and practicality in resource extraction. Furthermore, while bricks have a high amount of embodied energy, it can be offset by their aforementioned durability, as well by the continuous reuse and recycle of different structures over time, e.g. walls, landscape, paving and decoration (Calkins, 2009). The basic primary raw materials used for the production of clay bricks are generally nontoxic, such as clay, a material mainly composed of hydrous aluminum silicates; shale, a sedimentary rock that contains concentrations of clay, quartz and calcite; sand and lime. Due to the fact that the majority of raw materials used in clay brick production are from local sources, these materials may vary accordingly to the area where the extraction takes place. Regarding production, these raw materials are generally extracted in mines, transported to manufacturing facility, where they are crushed, graded and screened, mixed and molded to form bricks and finally dried and/or fired with varying gradations of heat. Regarding the type of manufacture, clay bricks can be classified as extruded, where the mixture of clay is extruded by a structure of wires to form the desired shape and hardened in mild temperature before firing; molded bricks, with a more moist structure than the former category, which is afterwards pressed into molds with hydraulic press and fired at high temperatures (900 to 1,000 Celsius degrees) (Calkins, 2009); and lastly, dry pressed, where the mixture is dried on fresh air. With regard to environmental impacts, clay bricks often have a greater energy expenditure (approximately from 150% to 400%, according to Calkins, 2009) when compared to other similar construction elements, such as CMUs (Concrete Masonry Units). Furthermore, in attempt to decrease their carbon footprint and also to increase their marginal profit, some manufacturers incorporate recycled components in their production line, such as fly ash, sewage sludge, crushed bricks, rice husk, slag or glass. More in-depth information related to environmental impacts is addressed in chapter two, namely â&#x20AC;&#x2DC;Cradle-to-Grave Analysis of Bricksâ&#x20AC;&#x2122;. Moreover, the use of clay bricks in civil construction provides advantages and disadvantages. Regarding the advantages, several can be mentioned: well-known construction technique, low maintenance, durability, availability of raw material, resistance to high temperatures and abrasion, compressive strength, good thermal insulation properties, sound attenuation characteristics, possibility of reuse and recycle, variety of block sizes and different options of brickwork bonding. With regard to disadvantages, it is important to highlight first the ones within the production process: inappropriate working conditions, environmental issues like GHG (Greenhouse Gases) emissions, land, energy and

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

water consumption. As an example, the construction sector in India contributes with 22% of the COâ&#x20AC;&#x2039;2 emissions. (Reddy and Jagadish, 2001). Regarding bricks used for construction purposes: low seismic resistance (once the mortar crack and crumble), reusability limited to the type of mortar applied, aesthetic changes within time, efflorescence, possibility of create mold and time consuming construction procedure.

1.2. Challenge Bricks are one of the oldest construction elements. Used in the Middle East, since 10,000 years ago, they can be found in ancient constructions of Romans, Jews, Arab, Hindus and Christians (Anwar and Khitab, 2016). In modern times, their use was disseminated after the Chicago fire, in the decade of 1870, as a substitute of traditional wood structures (Fischer, 2009). Nowadays, clay bricks are common sight in informal settlements which are growing rapidly all around the globe, as shown in Figure 01.

Figure 01: Example of brick usage (Ard-El-Lewa, Cairo) (Source: MAS Design/ETH ZĂźrich, n.d.)

The city of Hamburg is also known for the use of bricks, more specifically, red clay bricks, as they play an important role in the identity and cultural heritage of the city (City of Hamburg, Department of City Planning and Housing, n.d.), where several buildings use this material in their facades throughout the city (see Figure 02).

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

Figure 02: Map of Hamburg with buildings that use red clay bricks (marked in red) in their faรงades. (Source: Hamburg, Agency for City Development and Environment, 2014)

Bricks represent significant numbers in terms of production, construction purposes and construction and demolition waste (C&D). Researchers of the Department of Civil Engineering of the Indian Institute of Science in Bangalore estimated that India single handedly produces around 70 billion bricks per year (Reddy and Jagadish, 2001). In the European Union, 70% of the brick produced are destined for building construction purposes (Copenhagen Resource Institute, 2014). Bricks, together with tiles, concrete and ceramics, account for 25.93% (52.2 million tons) of the total C&D waste generated in Germany (201.3 million tons) during the year of 2012 (Deloitte, 2015), as seen in Figure 03.

Figure 03: Construction waste generation in Germany (Source: Deloitte, 2015)

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

According to the U.S. Geological Survey Mineral Commodity Summaries of 2015, 24.7 million tons of clay were produced in 2014 around the world, from which 7.5% of that amount was used to manufacture common brick, lightweight aggregate, and sewer pipes (U.S. Geological Survey Mineral, 2015). This number is higher than the years before and is attributed to the commercial and residential housing construction increase. Focusing on the national german context, it is noticeable that authorities aim to preserve natural resources. According to the European Environment Agency, the German government targets to “develop waste and closed-cycle management into a sustainable resource-efficient materials flow management over the coming years. By strictly separating wastes through pretreatment, recycling and the recovery of energy, Germany aims to make full use of substances and materials bound in wastes and therefore make landfill disposal of wastes superfluous.” (European Environment Agency, 2016). Examples of this are the German Circular Economy Act of 2012 (Kreislaufwirtschaftsgesetz) and the German Resource Efficiency Programme (ProgRess) launched in 2012. Besides the environmental issues, this last policy promotes the comprehension of resource efficiency as a fundamental tactic for innovation, growth and improving the competitiveness of the national economy. Summing up the wide span of facts mentioned above, brickwork is subject to unabated popularity. Since it is produced and ultimately demolished in large numbers, it exponentiates the impact of respective side-effects and issues regarding sustainability which are analysed in chapter two. The extraordinary relevance of this construction material attracted this group’s attention and, since the background of all group members lies within the field of architecture, we appreciated the opportunity to investigate more in local construction materials and techniques. Considering the city context, potential, relevance and history of brick architecture, the knowledge acquired by researching under a critical point a view about the entire process is used to develop proposals for Hamburg, aiming for the development of a more sustainable eco balance of bricks.

1.3. Circular Economy In order to better understand the relevance of our analysis and devise solutions for clay bricks in the city of Hamburg, in this subchapter a concrete definition of circular economy and cradle-to-cradle design is described. Furthermore, having a clear definition of these concepts is paramount for understanding the risks pertaining usual economic models sustainability-wise within the life cycle of bricks, which will be explored further in the second chapter, namely ‘cradle-to-grave analysis’. The traditional model of ‘take-make-consume and dispose’ dominates the global economy. After the industrial revolution, this pattern of growth based its development in the principle that natural resources can be considered “abundant, available, easy to source and cheap to dispose” (European Commission, 2014). However, this linear model exposes resources,

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

environment, society and business to diverse risks, such as natural resource depletion and constraints, environment fragility, high waste volumes, pollution and lower profits margins, to name a few. Therefore, in order to counteract these negative effects, a transition to the circular economy model is demanded. The Ellen MacArthur Foundation, a think-tank that promotes research on the redesign of economic frameworks, defines circular economy as the economy that “seeks to rebuild capital, whether this is financial, manufactured, human, social or natural.” (Ellen MacArthur Foundation, 2015). The Foundation also describes circular economy as a regenerative industrial cycle, where the usual end-of-life production approach is redesigned into a more superior, sustainability-driven production cycle in order to phase out the use of toxic materials that are currently impossible to be returned into the biosphere (Ellen MacArthur Foundation, 2013). Moreover, the circular economy framework eliminates the very negative connotation of waste, meaning that streams of residue are transformed into valuable resources, which can be reinserted several times into the production chain in order to replenish the different types of capital mentioned above (Ellen MacArthur Foundation, 2015; McDonough and Braungart, 2002). A diagram with a simple illustration of the circular economy concept is provided below, on Figure 04.

Figure 04: Circular economy diagram (Source: Sand & Birch, n.d.)

Moving towards a circular system requires much more than commitment: an integrated approach that engages several stakeholders such as governments, industry, policy makers, product designers, market models, educational institutes and consumers is necessary. Furthermore, for this report, within the concept of circular economy, we focus on ‘cradle-to-cradle’ school of thought, a way of design that is regenerative by nature, celebrates diversity and uses sustainable energy (McDonough Braungart Design Chemistry, 2012).

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

2. Cradle-to-Grave Analysis of Bricks The general lifecycle of a brick was divided into six phases with each containing multiple inherent problems regarding the environment, society as well as economy. Overall, the analysis reveals its linearity and predominantly cradle-to-grave practices. For a detailed explanation of the whole process, group objectives and proposed solutions see the Table 01 in Annex. ●

●

Phase 1 (Gathering of raw materials): Usually located in rural areas, clay pits or mines are the places where the material is obtained. The mining activity carries well known problems. The fact of being practiced for a long time and around the world aggravates the situation. High energy demand, land consumption, deforestation, soil degradation, social issues such as precarious, unhygienic and risky working conditions for employees, gas emissions (CO, CO2 NOx and SOx) (EPA, 2013), particulate matter emissions, and water pollution can be listed as main problems. Solutions for this are, therefore, aiming for improved mining practices such as increased efficiency and safety of equipment, use of alternative, renewable energy sources and treatment of the wastewater as well as stabilization and renaturation of degraded soil. Additionally, for example educational programs could help offering alternative sources of income and alleviate social pressure. Phase 2 (Production): This step is divided in 10 sub-phases according to the main activity in each step: storage, raw material size reduction, screening, forming and cutting, coating and glazing, drying, fitting and cooling, packaging, storage and, lastly, shipping. In general, the production phase demands material transportation along long distances with consequence of CO2 emissions and fuel consumption, mechanical energy consumption; and addition of chemical substances that cause environmental harmful gas emissions. For example, according to Venkatarama, B.V. and Jagadish, K.S., (2003), the amount of diesel consumed in transportation is approximately 5%-10% of the total energy embodied along the clay bricks manufacturing process. Moreover, bricks, cement and steel are the main responsibles to the total embodied energy in the building construction. Workers health is at risk and wastewater is contaminated and consumed in large amounts. Energy consumption is increased by the drying process (that needs temperatures from 50°C to 150°C) and by the firing and cooling phase (which needs temperatures from 538°C to 1316°C) (The Brick Industry Association, 2006). The high demand of thermal energy can be exemplified by the situation in developing countries, such as India. In this nation, the most popular fuels for burning bricks are coal, coal cinder and firewood, which leads to an average consumption of 0.20 kg of coal or 0.25–0.30 kg of firewood for the burning process of one brick. This means each brick of a size of 230mmx110mmx70 mm consumes 4.25 MJ (Reddy, and Jagadish, 2001). In addition, this fuels source increase the deforestation. Waste production and dumping on landfills completes the set of negative side-effects. While the severe environmental damages of phase 1 are well documented (Kim and Rigdon, 1998), the effects of phase 2 are less present if they are geographically detached from the process, e.g. by transporting the raw materials to another country for

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

● ●

●

further processing. According to the complexity of the processes and problems there is a broad variety of conceivable starting points for improvement which can be read up on in the annex. Some examples are clustering of production facilities to reduce transportation, make use of byproducts which are discarded usually, research alternative coating and glazing chemicals to reduce water pollution and allowing the brick to degrade, cluster drying halls or even the firing process with heat producing facilities such as incineration plants or use ventilated glasshouses in mediterranean or equatorial locations and produce and sell locally. Phase 3 (First use - building construction): Brick walls use mortar as adhesive to gain stability. In this phase these two elements are analyzed separately: Phase 3.1 (Solid materials - Bricks): On one hand, this construction technique is well-known and low tech. On the other hand it usually demands high amounts of workload and time. Some problems can be mentioned: material loss during construction accompanied by respective waste generation (brick pieces and packages) and chemical products used for cleaning the finished wall. Improvements impacting the ecobalance slightly would be recycling programs for packaging and smaller brick pieces e.g. by educating workers and architects about the appropriate use and design. Difficulties regarding the reuse of brick slabs in different contexts is user's preference to paint walls or change the original characteristics which can be reduced by image campaigns for the pure brick aesthetic. Phase 3.2 (Fluid materials - Mortar): Mortar constitutes about 17% of a brick wall (Calkins, 2009). One of the first mortars used was made out of lime. It was substituted by cement due to structural properties like resilience to water and precipitation. The kind of mortar applied has an important influence on the second use of a brick because cement mortar is strong and makes the breakup of brickwork into clean stones difficult handiwork. Generally, problems can be pointed out of in this phase: water consumption, health risks from cement dust and chemicals, chemical sealing application and waste production. These can be alleviated by reuse of greywater, better enforcement and monitoring of working laws and security equipment which workers tend to bypass according to own experiences of the authors from construction sites and, lastly, invest in research in alternative sealants and educate planners about intelligent building design methods to render sealants and cement mortar unnecessary. Phase 4 (First building use - Maintenance): As already mentioned, clay bricks are known for their durability, low maintenance and multiple uses. During the service life phase, bricks can suffer transformation due to climatic conditions, impacts or decoration activities. As explained in phase 3.1, changes in original aesthetic and durability characteristics limit the possibilities for reuse, hence, it is important to focus on the future problems that abrasive cleaning and antifungal products can cause. Natural and less aggressive biodegradable substances are recommended. Phase 5 (Demolition): At the end of the first use, bricks can be reused or recycled. Bricks for reuse need to go through a longer process, in which the time span, feasibility and results will mainly depend on the type of mortar. Disassembling and separating bricks from mortar is easier if lime was applied, since it is softer and easier to remove than the cement one. Removing cement mortar is possible;

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

â&#x2014;?

however it requires higher investments, labor and time. When this process is not feasible, bricks with mortar fragments can be crushed. Nevertheless, even when they still have added value, bricks are treated as construction waste and are deposited in landfills while they could be used for landscaping, pavement or filling. Several properties must be monitored and classified to guarantee the reused brick quality and appropriate reuse. Examples of these properties are: distressed appearance, frost resistance, soluble salts content, efflorescence, strength, water absorption, joints movement and sizes. In general, they should comply with the EN 771-1 for use in Europe. Besides the problems mentioned in previous phases, such as energy and fuel consumption, health risks for employees mainly by dust or hazardous substances, water consumption and particulate matter emission need to be addressed in this phase as well. Phase 6 (Crushing): Bricks with cement fragments cannot feasibly be reused and cannot continue in the value chain. They will be crushed and used as aggregates, base of fill materials for road construction, plant substrates or paving. This process demands energy consumption and will generate waste.

This lifecycle is unsustainable considering the triple bottom line (social, environmental and economic). Each of the mentioned problems can be tackled independently while a holistic approach unveils opportunities of tapping unused potentials, linking processes that benefit mutually. Nevertheless, as long as the process is a linear model and governments, industry, environmentalists, policy makers and product designers do not try to close to loop, all efforts, investments and actions will have a limited effect and the problem of discarding valuable material, work and energy will persist to a certain extent.

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

3. Solutions for Hamburg Narrowing down the general approach of the life cycle assessment regarding problems and solutions, is necessary to focus on goals that are within reach. Hence, the following chapter will introduce four very different concrete proposals for Hamburg. Anticipating the detailed statements in this chapter, they all share the main objective of supporting the closure of loops: 1.

The use of lime mortar instead of cement mortar simplifies the disassembly of brickwork and the reclamation of entire bricks for a second use. See the table in the annex for the effects on the phases of the conventional brick lifecycle. Moreover, unlike cement, lime follows a technical circle and is recyclable.

2. The new material Hempcrete incorporates a high amount of recycled content of brick production but also of other production processes, hence, feeding back into its own lifecycle as well as interweaving the lifecycles of other products. 3. Reusing brick walls is an innovative approach and change in working methods instead of substitution of materials. It is an economically feasible way to loop back within the lifecycle of brickwork by using the bricks a second time. 4. The concept of industrial symbiosis searches particularly for links of production processes between different stakeholders, repurposing products at their end of life, thus, resetting and reprogramming their lifecycles.

3.1. Lime Mortar Lime mortar was used since 14.000 years ago in Turkey and in the Middle Ages for all kinds of brickwork and different types of buildings from natural stone walls to aqueducts (Only in the beginning of the 19th century portland cement and cement mortar have been developed and became the new standard in building construction (Beton.org, n.d.; Maier, 2012). The technical cycle shown below in Figure 05 explains the working principle of lime mortar: Naturally occurring calcium carbonate is burned at 898Â°C to be reduced to burnt lime or quicklime by stripping it from carbon. This intermediate product is hydrated in a strong exothermic reaction to create calcium hydroxide. Afterwards, this slack lime is mixed with more water and applied to the brick. Under the influence of air the mortar sets, takes up carbon and forms the natural crystalline structure of calcium carbonate or limestone,

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

providing the strength of 2.5 MN/m² (Baunetzwissen.de, n.d.) and fixing the bricks in their place.

Figure 05: Technical circle of lime (Source: Harseim, Henriques and Román, adapted from KLEIN, T, 2005)

The technical circle shows that lime mortar consists mainly of natural materials, i.e. sand, so it can naturally degrade without harming the environment. Additionally, it takes up the carbon dioxide that it released into the atmosphere. Due to its softness and breathability leading to crystallisation of salt on its surface, it is the sacrificial element in brickwork and cheaper to repair than deteriorated bricks as seen from an economic and environmental perspective (Vogdt, 2012). Regarding embodied energy content it is to mention, that lime mortar has the lowest amount among the known mortars: 732 MJ/m³, which is about 30% less than the embodied energy in the widely used cement mortar (1268 MJ/m³), as reported by Reddy and Jagadish (2001). These characteristics are the reason for the proposal of reintroducing lime mortar in modern construction to enable the reuse of bricks. Masonry created with lime mortar is easier to disassemble and the bricks can be cleaned without harm by simply scrubbing and dusting off the mortar with a sharp tool which is possible due to strength losses of mortar in time (Brick Development Association, 2014). This allows us to add more phases to the assessed life cycle as shown in the annex: reclaimed bricks can be collected from the demolition or dissembling site, stored according to the different types and transported to the new construction site before being used again in building construction or for other purposes such as masonry, landscape, decoration or paving. As long as lime mortar is used,

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

the last phases can and should be repeated as long as the material allows it, in order to circulate the high valued brick and its embodied energy as well as environmental sacrifices for a long time inside the value chain. The idea of reusing bricks developed as follows: a variety of companies especially in the northern part of Germany, for example Spolia, located in Lübeck, or Ziegelkontor, located in Born auf dem Darß, are specialized on reclaiming and selling used bricks. Their reference objects show the popularity and usability and even increased aesthetic value of the aged product. Obviously, the shorter lifespan and reduced strength compared to cement mortar which can take up to 10MN/m² (Baunetzwissen.de, n.d.) are a weakening of the brickwork, but with modern calculation tools the masonry can be dimensioned precisely and buildings can be designed accordingly with consideration to different properties and without any structural disadvantage. Moreover, modern constructions in the residential, industrial and service/office sector in the developed as well as in the developing countries (see Figure 01, an example informal settlement) are oftentimes based on horizontal concrete slabs carrying freestanding walls without the function of structural support, rendering extremely strong masonry unnecessary and indicating the global usability of lime mortar. Considering the amount of the construction types, multi-storeyed buildings consume the highest amount of energy: 21 tonnes of coal/100 m² (or 4.2 GJ/m²) (Reddy and Jagadish, 2001). However, the minimal water resilience and its vulnerability to frost damage causes a significant problem in colder and humid climates such as it is the case in Hamburg. Thus, requiring protection from freezing for three months and appropriate building design, e.g. by using oversized roofs for domestic purposes or sandwich systems adding a protective facade layer in front of the wall, in order to keep maintenance costs low and competitive with cement masonry. Nevertheless, considering the increased investment in work and energy regarding the manual disassembly of walls, cleaning, sorting and transportation of the reclaimed brick and the aesthetic appreciation, the effect of this proposal is expected to be very limited since, judging from the majority of reference objects of specialized companies, the expensive reclaimed bricks shall be displayed openly and in traditional German building styles. Having stated that, it is clear that this treatment of bricks is inappropriate in the climate of Hamburg and the combination of reclaimed bricks and lime mortar is limited to indoor use, for example as decorational filling of timber framework. Research indicates that the traditional lime mortar can be improved with natural materials, counteracting its two predominant weaknesses of vulnerability to water and pressure. Inspiration can be drawn from Mexico where mucilage of opuntia plants is commonly believed to increase water resilience if mixed into the mortar (Cárdenas et al., 1998) or from China and the throughout Asia widely used sticky-rice lime mortar with its increased performance (Yang et al., 2010). Instead of adapting building design for usage of walls made from reused bricks, the common practices could be preserved if these organic-inorganic compounds are developed and were to be applied in Hamburg.

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

3.2

Hempcrete

The second solution proposed is related to hempcrete, a new material, not very explored yet, but with high sustainable potential. Hempcrete was developed as an alternative to the traditional concrete. When analyzing the concrete industry, it is possible to identify several disadvantages regarding environmental issues and concrete use. As an example, cement production influences global warming and climate change due to GHG emissions. It is estimated that to each ton of cement production, about one ton of greenhouse gases is emitted (Kumar, Manohari, Rani & Sunil, 2016). In addition, alternative building materials have an embodied energy of 3–5 GJ/m2 of built-up area (Reddy and Jagadish, 2001), which reinforce the suggestion of its appliance to reduce the building energy content. Its aim is to produce a concrete that can incorporate recycled content from existing concrete, waste materials from other production sectors and, at the same time, reduce natural resources depletion. As a result, Hempcrete is a bio-composite mix of agricultural fibers, combining hemp boon, lime hydrate, cement and water (Hela and Mikulica, 2015). More of its process is illustrated on Figure 06, below. One of the main natural fibers used is the Cannabis sativa L, which is known as “Industrial Hemp”. It is a fast growing annual crop (1.5 - 4m height) that develops in the plant around the woody core. This core is cut into small sizes (5-25mm) and mixed with the other components. (Kumar, Manohari, Rani and Sunil, 2016). Cement is used as a binder and to accelerate setting time. However, different options of binder additives can be used as well: pozzolanic ash, clay and natural cement, for example. In order to simplify the manufacturing, save resources, reduce waste disposal and use less chemical substances, the hemp is added to the mix as a raw material, without previous treatment. When the surface of hempcrete walls is dry, they must be covered with a lime and plaster finish.

Figure 06: Chopped hemp fibre, hempcrete block, hempcrete wall construction, hempcrete wall finish (Source: Kumar, Manohari, Rani and Sunil, 2016)

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

Several advantages of this material can be highlighted in the crop production and as a building material. The hemp plantations are able to grow with minimal additional nutrient and without fungicides, herbicides or other pesticides. It also has high availability worldwide, since it grows in most temperate and subtropical climates (See Figure 07). As a construction material, it offers high thermal and acoustic insulation; faster speed in construction; pest, mold and rot resistance; reusable content; building humidity and temperature control and, as consequence, higher energy efficiency than clay bricks; lightweight blocks; fire resistance; earthquake resistance; multiple finish options; multiple uses (walls, floors and ceilings) and less construction waste, since it requires less foundations due to the lighter walls (Beckerman, 2014).

Figure 07: Hemp worldwide current large scale production indicated by the green dots Source: Ahlberg, Georges & Norlén, 2014

In addition to these advantages, the fact of the material be carbon negative along its life, is noteworthy. Different values of CO2 sequestration are estimated, as a consequence of different methodologies and different material proportion for the blocks. However, the most important is to understand that the proposed material is able to absorb CO2 , turning it carbon negative or a carbon reductor along the lifecycle. Sahmenko & Sinka (2013) state that researchers declared different amounts of CO2 sequestration along the material lifecycle: 4 kg/m³, 108 kg/m³, 120 kg/m³. This characteristic has significant relevance when considered that about 10% of global CO2 emissions come from building materials manufacturing processes (Sahmenko and Sinka, 2013). Thus it is plausible to develop materials which are able to avoid and reduce this number. Hemp, like other plants, absorbs CO2 while growing and releasing oxygen. Nonetheless, hempcrete is capable to continue absorbing CO2 as a block. The explanation is associated with the lime solidification process, which requires CO2 . Furthermore, the blocks are finished with a breathable layer that allows the process of carbon sequestration to continue.

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

Nevertheless, there are disadvantages regarding feasibility, inherent material characteristics and climate conditions that need to be considered. First, on one hand, hempcrete can not be used as direct load bearing material due to low compressive strength and low modulus of elasticity. However, on the other hand, since its compressive strength increases over time, it can be applied in timber stud walls as infill material. Second, the production process demands large amounts of water, as hemp fibers are highly porous and can absorb significant water amounts - approximately 5 times of their weight (Rhydwen, 2016). In addition, this condition leads to long drying periods (2-3 months), which may impair large-scale production in industry. Third, weather conditions have influence along the hempcrete process, as construction must be done when temperatures are above 5°C, since lime is vulnerable to frost damage. This restriction originated the recommendation of applying this construction technique only from February to September. Fourth, the crop harvesting period is limited since hemp is harvested usually at the end of summer. This characteristic turns the material storage necessary along fall and winter. As a consequence, prices are increased and a better logistic plan is needed. Narrowing to the city of Hamburg, the solution proposed needs to be more questioned to analyze local advantages and disadvantages. As advantage, hemp is largely available in the city surroundings. As a disadvantage, since the temperatures below 5°C are not appropriated for this technique, the city's weather conditions can reduce the usable timeframe for construction. However, as is what perceived along this research, this construction material is vastly offer in regions with high amounts of rainfall and low temperatures, such as England. The employment of hemp (considered an agricultural waste material) in concrete masonry blocks promotes a wide market for industrial hemp usage in a sustainable context and under the circular economy. The material is relatively new (the first use was in France during the decade of 1990) and several researches are being held by universities and industries in order to obtain more precise information about the material resistance, durability, better usages, components, benefits, weaknesses and how to improve the material overall. This interest reflects the engagement of academia and the market in the process, investing time, personal and economic resources.

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

3.3. Reclaimed Brick Wall As explained in chapter 3.1. the potential of lime mortar lies within its ease of removal so that the single bricks can be reclaimed and reassembled. Figure 08 points out the insufficient economic feasibility by setting up a comparison between the usual life cycle and the life cycle for the proposal of reclaimed bricks. One commonly known collinearity serves as assumption to conduct a simple qualitative assessment of the life cycles: industrialized processes are due to various factors less time consuming than manual labour and therefore more expensive than industrialized labour (Germany. German Federal Ministry for Environment, Nature Conservation, Building and Nuclear Safety, 2015: 105).

Figure 08: Qualitative diagrammatic comparison of life cycles approached with different proposals (Source: Harseim, Henriques and Román, 2016)

Each phase is assigned a number of symbolic € sign as an abstract unit/variable according to the amount of manual labour conducted, representing the relation of the amounts of required workload. The first steps of gathering of raw materials and the industrialized production of the bricks require certain investments, nevertheless each one is comparatively cheaper than the following manual construction done by workers onsite. As explained before, some of the appreciated advantages of bricks are their durability and low maintenance, causing the phase of service life to be low on investments. The differences develop after this phase: In the traditional cradle-to-grave life cycle, the demolition of a building would be done efficiently and fast with crude machines, without postprocessing and the products will be dumped in a landfill. The life cycle of reclaimed bricks requires a manual disassembly which takes up a high amount of time, workforce and money, similar to the prior assembly. It involves an intermediate phase of recollection, cleaning, storage and transportation of the single bricks, before they can be used a second time - being assembled manually again in time consuming labour. Since they underwent treatment and exposure to climatic stress they need special attention and care in their second service life before they can be demolished in industrialized processes at the end of their life. Comparing the amount of €-units spent on the construction of one house results in the insight, that the cradle-to-grave-production requires 9€-units whereas the reclaimed brick proposal would be more expensive at 9.5€-units (total 19€-unit in Figure 08, hence, average for one building 19/2= 9.5€-unit). To counteract the apparent economic infeasibility a new proposal is suggested: instead of demolishing the brick wall at the end of life of a building, it will be separated as one entity or cut into blocks of reasonable sizes, reclaimed,

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

transported to another construction site or to another part of the same building in case of renovation. This changes the life cycle as shown in Figure 09 to an expected 14â&#x201A;Ź-unit in total and an average of 7â&#x201A;Ź/unit per building due to manual or partly industrialized and less time-consuming disassembly than for the reclaiming of bricks.

Figure 09: Qualitative diagrammatic representation of predicted investments during life cycle of reclaimed brick wall proposal (Source: Harseim, Henriques and Roman, 2016)

Post processing and sorting of single stones is no longer required, as the brick walls can then be used a second time for building construction and be assembled quickly in environments comparable to the source building by a few workers with the use of cranes and industrial tools. Moreover, the brick wall is treated like a prefabricated wall slab and its use is not limited to decorative purposes. Since the bricks do not undergo stressful treatment and since their cost is approximately 77% (according to the assumptions made above) of a building constructed from freshly produced bricks, they will be feasible to use not only as outer walls but also as inner walls that will be covered, requiring less maintenance and care. This proposal corresponds to the current development in modern construction industry of increasing size of blocks and use of cranes within prefabrication structures (Prochiner, 2006: 96; Vodgt, 2012), as illustrated in Figure 10.

Figure 10: Transport of prefabricated brick walls and assembly of big block masonry using hydraulic aids. (Source: Chamber of Commerce, 2016)

As stated by Brameshuber and Vollpracht, from the Institute for Research in Construction from the RWTH Aachen University (2014), the construction technology of prefabricated brick walls is known and reliable practice for many years as a reaction towards the economic pressure in the construction industry and is used for domestic as well as industrial properties. Advantages are not only reduced costs, shorter construction periods, but also a

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

reliable level of quality, as well as precise measurements (Prochiner, 2006: 100). Reclaimed brick walls are similarly fast to construct since they are of similar dimensions. Since they do not require the assembly of single stones unlike the known industrial automatised production of brick elements they are inexpensive. Another difference is the quality and precision of the wall which can only be as good as the initial (manual) production allowed. The remaining striking advantages for Hamburg are the speed and price supporting investors facing the challenge of creating affordable residential and office space as fast as possible. Not only does this satisfy the excessive demand within this city, it also helps in complying with particular building codes and binding site plans, dictating the use of bricks, as is the case in Hafencity (Germany. City of Hamburg, 2013). Depending on the producer, the costs per square meter of traditional masonry and brick elements differ marginally (Komzetbau BĂźhl, 2011), as shown in Figure 11 below. Nevertheless, it is clearly visible, that the material price of the brick element accounts for about 80% of the construction costs revealing the potential savings possible by the reclamation of existing brick walls.

Figure 11: Comparison of production costs of different construction types of masonry (Source: Komzetbau BĂźhl, 2011)

The German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (2015) states in its assessment of the the costs in the construction sector, that automated production of systemic solutions such as brick elements and their advantages are not commonly known. The reason being lack of information and marketing due to strong lobbyism. Considering the popularity of brick buildings in Hamburg, untapped potential lies within the dissipation of information and raising of awareness for brick elements.

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

3.4. Industrial Symbiosis Closely related to the concept of circular economy, industrial symbiosis is defined as a local cooperation that can be established with the buying and selling of resources within private companies, as well as public stakeholders, wherein the residual product of one company is used as a resource by another one and mutual economic and environmental benefits for the involved stakeholders are generated (Møller, 2016; Symbiosis.dk, n.d.). This collaboration generally involves physical exchange of materials and by-products through the optimisation of infrastructures and transportation, in the means of developing combined processes for the elimination of overlapped manufacturing between industries (European Commission, 2013). As similar to the drivers depicted within the transition to circular economy, the cooperation between companies tries to counteract the scarcity of resources and to create a more efficient, cost-minimizing waste management in a tailored, context-adapted solution that essentially promotes the collaboration of different companies and governmental spheres towards circularity. Other driving forces for the implementation of an industrial symbiosis in urban areas are: the possibility for its members to have access to resources below the market price; the increase in security supply of resources through local synergies; the raise of competitiveness and joint investments in the market that directly benefits final consumers; and, apart from the direct creation of economic incentives for companies, also the fostering of innovative business models that promote the reduction of carbon footprint due to the more efficient use of resources (Møller, 2016). Considering the current brick production in Hamburg and its effects on the overall waste generation, the concept of industrial symbiosis could be applied to devise more agile solutions in order to economically integrate aforementioned stakeholders in the city-level, as well as to decrease the amount of generated waste to comply with European Union’s guidelines in the Circular Economy Package by promoting innovative industrial processes (European Commission, 2015). Finally, for our fourth solution, we propose the application of an industrial symbiosis in the city of Hamburg between three different partners, chosen considering aspects such as optimal reuse of resources, geographical location of companies, economic feasibility within each partner’s scale and long-term interest in collaboration due to adequation of resources. Moreover, the funding could be done under the Horizon 2020, an initiative promoted by the European Commission for the implementation of forerunner projects and research in the industrial branch and would consist of a partnership between three companies located in the southern region of the city: a treatment plant from Hamburg Wasser, known as Klärwerk Köhlbrandhöft; Hanseaten-stein Ziegelei GmbH, a medium-sized clay brick manufacturer and Heidelberger Beton Hamburg, a manufacturer of concrete (as depicted in Figure 12).

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

Figure 12: Proposed industrial symbiosis partnership in Hamburg (Source: Harseim, Henriques and Román, 2016)

The project would be divided into two main phases, where the first phase constitutes the cooperation between the sewage treatment plant (described as ‘01’ in the previous picture) and the clay brick manufacturer (described as ‘02’) and the second phase would consist of cooperation between the latter and the concrete manufacturer (described as ‘03’). Regarding the first phase, we propose the reuse of sewage sludge from the treatment plant as a raw material for clay brick production, as research has shown that clay bricks produced with a certain percentage of recycled sludge present physical characteristics that are suitable for being used as common bricks, with improved thermal performance if compared to common ones (Weng, Lin and Chiang, 2003; Liew, 2004; Eliche-Quesada et al., 2011). For the second phase, we propose a cooperation between Hanseaten-Stein Hamburg and Heidelberger Beton Hamburg through a partnership between the supply of reclaimed bricks on the part of the brick manufacturer for the crushing and further use by the concrete manufacturer as an adequate aggregate coarse material in the production of low-level engineering concrete (Khalaf and DeVenny, 2005; Debieb and Kenai, 2008). Naturally, being an innovative economic approach that requires the cooperative effort of different stakeholders in very diverse levels, e.g. the Hamburg Senate and the European Union as potential major sponsors and the three aforementioned companies; as well a considerable change in the Business As Usual (BAU) models; as well deeper changes in the legal framework and in industrial sphere, this solution may take more time to be implemented, if compared to solutions like the use of lime mortar or the reclaim of entire brick walls. However, this solution, apart from proving to have several advantages that were already mentioned, also means to put Hamburg and, therefore, Germany in the forerunner position to serve as example of cities that are currently implementing circularity and the concept of industrial symbiosis in a feasible and realistic way.

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

4. Conclusion Based on the assessment of chapter two, it is to be noted that the conventional life cycle of a brick is linear and problematic. Considering the issues, popularity, production numbers, depletability of resources and the respective targets within EU policies, it is justifiable an in-depth analysis of the potential for circular economy within brick production. Subsequently, resulting in a discussion of four concrete proposals which are referring to the concept of circular economy in various ways, as pointed out in chapter three. The comparison of the developed proposals is visualized below in the matrix for green features of sustainable building materials, adopted from College of Architecture and Urban Planning of the University of Michigan (Figure 13) and explained in the following paragraphs. The criterias are grouped in three columns representing the main stages of a lifecycle (Production, service life, demolition) and every criteria that applies to a certain proposal received a respective label displaying the number of the proposal. 01 Lime mortar: This proposal does not reduce the amount of waste in the production but itâ&#x20AC;&#x2122;s natural ingredients helps preventing pollution. The technical circle of lime contributes the advantage of recyclability. Lime mortar contains a comparatively low amount of embodied energy as explained in chapter three. Since lime mortar is part of brick walls which serve as thermal reservoir, storing and releasing energy, abating cooling and heat demand, this proposal increases energy efficiency of a building during its operational phase and supports the storage of solar energy (RES). Since lime mortar is weakens in time and crumbles it cannot boast of increasing the life expectancy of a building. The natural materials are nontoxic and maintenance, e.g. cleaning of walls, can be done without water pollution. Residuals are biodegradable and recyclable, the bricks reusable. GHG emissions stay embodied and trapped inside the durable bricks or are circulating in the carbon-neutral technical lime circle. 02 Hempcrete: If hempcrete buildings are designed bearing in mind the block sizes, it is possible to create a minimal amount of construction waste. It contains a significant amount of recycled ingredients but the conglomerate of these, each carrying their own ecological footprint, cannot be considered pollution preventive. Nevertheless the production of hempcrete blocks requires a lower amount of energy since it requires drying but no firing. Hemp is a natural, non-toxic material with good insulative characteristics, thus, influencing the energy efficiency of a building positively. The lightweight blocks have low thermal capacity and can not store solar energy very well. The hemp plant as well as the hempcrete block absorb carbon dioxide during their life, acting as a carbon sink and reducing GHG in the atmosphere. 03 Reclaimed brick wall: Without wasting walls or pieces a second use should be promoted. The assembly requires less mortar or adhesives than traditional masonry, helping to prevent pollution during construction and is nontoxic. It contains a high amount of embodied energy without recycled materials using the strength to circulate these in a long lifecycle. Just like the traditional brick wall the reclaimed wall will store (solar) heat energy increasing the energy efficiency of a building. Additionally, if the typical very strong cement

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

mortar is used, the reclaimed brick wall has the advantage of increased life expectancy. The fired bricks are not biodegradable but recyclable as aggregates or can be reused repeatedly as wall. 04 Industrial symbiosis: This proposal is special due to its nature as being a concept instead of being a kind of physical product. Therefore, itâ&#x20AC;&#x2122;s strengths are to be found in the potential waste reduction if production processes are linked and even usually discarded intermediate products are put to use. The suggested use of sewage sludge for example prevents water pollution and recycled crushed bricks are used as aggregates in concrete production. Demolished products are recycled and reused. Linkage of processes reduces GHG emissions on various stages, e.g. by cutting transport distances and fuel consumption. We can see that most of the proposals lead to improvements in the manufacturing process or in the waste management and criteria regarding the building operation is less addressed. The ranking of proposals according to the number of addressed environmental criteria is: Lime mortar (12), reclaimed brick wall (8), Hempcrete (7) and Industrial symbiosis (6).

Figure 13: Overview of positive effects of all proposals regarding sustainability criteria. (Source: Harseim, Henriques and RomĂĄn, 2016. Adapted from Kim, 1998)

However, it can not be derived from this ranking, that proposal of lime mortar is the ideal one for Hamburg because sustainability comprises more than only environmental factors. If the proposals are ordered anew according to their economic feasibility as shown in Figure 14, using the required amount of changes in the Business As Usual models of the construction industry as an indicator and the expected strength of positive impact the ranking changes: Hempcrete will have the biggest positive impact due to the characteristics discussed above while being constructed with well-known methods. It is followed by the

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

industrial symbiosis approach in terms of potential impact but it requires a lot of changes and rewiring of processes between different stakeholders. The reused brick wall uses known techniques and has a comparatively high impact among the group of proposals due to its theoretically nearly endless iteration of service life phase. Lime Mortar will most likely have a low impact because it is very limited in the use of modern architecture and construction (design and time frames). The proposals complement each other in their positive effects or overlap, strengthening the potential impact on the city, hence, a combination of proposals turns out to be the solution for Hamburg with the proposals being implemented in phases: The ones asking for a small change in the business as usual will be realized first (lime mortar and reused brick walls) while stronger changes within greater societal, governmental and industrial sectors require more time and development (industrial symbiosis). Since some proposals hinder each other or contradict, namely the promotion of soft lime mortar and the strength-requiring reclaimed brick wall, a decision has to be made. The proposal of lime mortar can be disregarded due to its limited expected impact which highlights the reclaimed brick wall as preferable. Additionally, as shown in chapter three life-cycle under the lime mortar and reclaimed brick proposal turned out to be more expensive than the economically feasible solution of reused brick walls rendering its implementation unrealistic. Zooming out to an international scale, the solution regarding Hempcrete has a better applicability in warmer climates. The advantages are related with the fact that the crop can be harvested along the entire year, not limiting a timeframe for that. As a consequence, there is no need to store the material during cold seasons, reducing the costs and increasing competitiveness in the market. In addition, the high temperatures enable to apply this construction technique along the whole year.

Figure 14: Expected correlation of impact and required changes in BAU of the proposals (Source: Harseim, Henriques and Romรกn, 2016)

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

V. References AHLBERG, J., GEORGES, E. NORLÉN, M. (2014) The potential of hemp buildings in different climates - A comparison between a common passive house and the hempcrete building system [Online] Available from: http://www.diva-portal.org/smash/get/diva2:722306/FULLTEXT01.pdf [Accessed: September 6th 2016]. ANWAR, W, KHITAB, A. (2016) Advanced Research on Nanotechnology for Civil Engineering Applications. Hershey: IGI Global. BAUNETZWISSEN.DE (n.d.) [Wall mortar] Mauermörtel (in German) [Online] Available at: http://www.baunetzwissen.de/standardartikel/Mauerwerk_Mauermoertel_162672.html [Accessed: September 5th 2016]. BECKERMAN, J. (2014) Hempcrete Sustainability & Superior Performance. In EcoBuilding Guild Retreat. Seattle, October 10, 2014. [Online] Available from: http://www.ecobuilding.org/conference/previous-years/presentation-files/2014-presentations/ EB2014Hempcrete.pdf [Accessed: September 5th 2016]. BRAMESHUBER, W. and VOLLPRACHT, A. (2014). [Yearly Report of Building Material Science Module from the Institute for Research in Construction] Jahresbericht 2014 des Lehrstuhls für Baustoffkunde am Institut für Bauforschung (in German). RWTH Aachen University: Aachen. BETON.ORG (n.d.) [History of Concrete] Geschichte des Betons. (in German). [Online] Available at: http://www.beton.org/wissen/beton-bautechnik/geschichte-des-betons/ [Accessed: September 5th 2016]. BRICK DEVELOPMENT ASSOCIATION (2014). BDA comment on the use of Reclaimed Clay Bricks. In: Brick work: Association of Brickwork Contractors: London. CALKINS, M. (2009) Materials for sustainable sites: a complete guide to the evaluation, selection and use of sustainable construction materials. John Wiley & Sons: Hoboken. New Jersey. CÁRDENAS, A. et al. (1998). On the possible role of Opuntia ficus-indica mucilage in lime mortar performance in the protection of historical buildings. Journal of the Professional Association for Cactus Development. CLUB OF ROME. (2015) The Circular Economy and Benefits for Society Jobs and Climate Clear Winners in an Economy Based on Renewable Energy and Resource Efficiency - A study pertaining to Finland, France, the Netherlands, Spain and Sweden. [Online] Available from:

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http://www.clubofrome.org/wp-content/uploads/2016/03/The-Circular-Economy-and-Benefitsfor-Society.pdf [Accessed: August 18th 2016]. DEBIEB, F. and KENAI, S. (2008). The use of coarse and fine crushed bricks as aggregate in concrete. Construction and Building Materials, 22(5), pp.886-893. DELOITTE. (2015). Construction and Demolition Waste management in Germany V2 – September 2015. [Online] Available from: http://ec.europa.eu/environment/waste/studies/deliverables/CDW_Germany_Factsheet_Fina l.pdf [Accessed: August 20th 2016]. ELICHE-QUESADA, D., MARTÍNEZ-GARCÍA, C., MARTÍNEZ-CARTAS, M., COTES-PALOMINO, M., PÉREZ-VILLAREJO, L., CRUZ-PÉREZ, N. and CORPAS-IGLESIAS, F. (2011). The use of different forms of waste in the manufacture of ceramic bricks. Applied Clay Science, 52(3), pp.270-276. ELLEN MACARTHUR FOUNDATION (2013) Towards the Circular Economy: Economic and business rationale for an accelerated transition [Online] Available at: https://www.ellenmacarthurfoundation.org/assets/downloads/publications/Ellen-MacArthur-F oundation-Towards-the-Circular-Economy-vol.1.pdf [Accessed 10 Jun 2016] ELLEN MACARTHUR FOUNDATION. (2015). Circular Economy System Diagram. [Online] Available from: http://www.ellenmacarthurfoundation.org/circular-economy/interactive-diagram [Accessed: August 15th 2016]. EUROPEAN COMMISSION. (2013). Factories of the future: multi-annual roadmap for the contractural PPP under Horizon 2020 [Online] Available from: http://www.effra.eu/attachments/article/129/Factories%20of%20the%20Future%202020%20 Roadmap.pdf [Accessed: August 20th 2016]. EUROPEAN COMMISSION. (2014). Towards a circular economy: A zero waste programme for Europe. [Online] Available from: http://ec.europa.eu/environment/circular-economy/pdf/circular-economy-communication.pdf [Accessed: August 20th 2016]. EUROPEAN COMMISSION. (2015). Closing the loop - An EU action plan for the Circular Economy. Brussels: European Commission. [Online] Available from: http://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1453384154337&uri=CELEX:52015DC0 614 [Accessed: August 20th 2016]. FISCHER, M & LORENZ, W. (2009) Early Reinforced Brick Floors in Germany: Historical Development, Construction Types, Dimensioning and Load Bearing Capacity. In Proceedings of the Third International Congress on Construction History. Brandenburg University of Technology Cottbus, Germany 20th – 24th May 2009. Berlin: NEUNPLUS1

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GERMANY. GERMAN FEDERAL MINISTRY FOR THE ENVIRONMENT, NATURE CONSERVATION, BUILDING AND NUCLEAR SAFETY. (2015) Overview of the German Resource Efficiency Programme (ProgRess) [Online] Available from: www.bmub.bund.de/P1742-1/ [Accessed: August 28th 2016]. GERMANY. GERMAN FEDERAL MINISTRY FOR THE ENVIRONMENT, NATURE CONSERVATION, BUILDING AND NUCLEAR SAFETY. (2015) [Report from the Commission for Decrease in Construction Costs within the scope of the Coalition for affordable Housing and Construction] Bericht der Baukostensenkungskommission im Rahmen des Bündnisses für bezahlbares Wohnen und Bauen (in German). [Online] Available from: http://www.bmub.bund.de/fileadmin/Daten_BMU/Download_PDF/Wohnungswirtschaft/buend nis_baukostensenkungskommission_bf.pdf [Accessed: September 28th 2016]. GERMANY. CITY OF HAMBURG. DEPARTMENT OF CITY PLANNING AND HOUSING. (n.d.) [Typical Hamburg! Clay bricks in Hamburg] Typisch Hamburg! Backstein in Hamburg: die Überdämmung der Fassaden gefährdet das baukulturelle Erbe Hamburg (in German). [Online] Available at: http://www.hamburg.de/backstein/ [Accessed: September 5th 2016] GERMANY. CITY OF HAMBURG. (2013) [Statement for development plan in HafenCity 11] Begründung zum Bebauungsplan HafenCity 11 (in German). [Online] Available at: http://daten-hamburg.de/infrastruktur_bauen_wohnen/bebauungsplaene/pdfs/bplan_begr/haf encity11.pdf [Accessed: September 5th 2016] HELA, R. and MIKULICA, K. (2015) Hempcrete - Cement Composite with Natural Fibres. Advanced Materials Research [Online]Vol. 1124, pp. 130-134 Available from: http://www.ecobuilding.org/conference/previous-years/presentation-files/2014-presentations/ EB2014Hempcrete.pdf [Accessed: September 5th 2016]. KHALAF, F. and DEVENNY, A. (2005). Properties of New and Recycled Clay Brick Aggregates for Use in Concrete. J. Mater. Civ. Eng., 17(4), pp.456-464. KIM, J. (1998). Sustainable Architecture Module: Qualities, Use, and Examples of Sustainable Building Materials. In: College of Architecture and Urban Planning: The University of Michigan. National Pollution Prevention Center for Higher Education. KOMZETBAU BÜHL (2011). [Sample calculation of brickwork] Musterkalkulation Ziegelmauerwerk. (in German). In: Kompetenzzentrum der Bauwirstschaft. KUMAR, A., MANOHARI, N., RANI, D., SUNIL. H. (2016) Manufacturing of building blocks using Hempcrete. International Journal of Latest Research in Engineering and Technology [Online] Volume 02: 62-73 Available from: http://www.ijlret.com/Papers/Vol-2-issue-7/10-B2016344.pdf [Accessed: September 5th 2016].

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LIEW, A. (2004). Incorporation of Sewage Sludge in Clay Brick and its Characterization. Waste Management & Research, 22(4), pp.226-233. MAIER, J. (2012) [Manual for Historical Brickwork: Methods of Research and Restoration Processes] Handbuch Historisches Mauerwerk: Untersuchungsmethoden und Instandsetzungsverfahren. Springer. MØLLER, P. (2016). Industrial symbiosis: a case-study of Kalundborg Symbiosis. Hamburg Copenhagen Urban Challenge. Technical University of Denmark. Copenhagen. Lecture held on August 18th 2016 MCDONOUGH, W. and BRAUNGART, M. (2002). Cradle to cradle. New York: North Point Press. MCDONOUGH BRAUNGART DESIGN CHEMISTRY. (2013) Overview of the Cradle to Cradle Certified CM Product Standard – Version 3.0 [Online] Available from: http://epea-hamburg.org/sites/default/files/Certification/C2CCertified_V3_Overview_121113. pdf [Accessed: August 23th 2016]. PROCHINER, F. (2006) [Future-oriented concepts for Manufacture and Assembly implemented in industrialized housing construction] Zukunftsorientierte Fertigungs- und Montagekonzepte im Industriellen Wohnungsbau. In: Munich Technical University. Faculty of Architecture: Munich. REDDY, B.V. and JAGADISH, K.S. (2001). Embodied energy of common and alternative building materials and technologies. Energy and Buildings 25 (2003) 129-137 RHYDWEN, R. (2016) Building with Hemp and Lime [Lecture] Graduate School of Environment. Centre for Alternative Technology. http://www.growingempowered.org/wp-content/uploads/2016/02/Building-with-Hemp-and-Li me.pdf [Accessed: September 5th 2016]. SAHMENKO, G., SINKA, M. (2013) Sustainable Thermal Insulation Biocomposites from Locally Available Hemp and Lime. In Proceedings of the 9th International Scientific and Practical Conference. Volume 1. Riga Technical University, June 20-22, 2013. Rezekne: Rēzeknes Augstskola. pp 73-76 SYMBIOSIS.DK (n.d.). Kalundborg Symbiosis: the world’s first working industrial symbiosis. [Online] Available at: http://www.symbiosis.dk/en [Accessed 6 Sep. 2016]. UNITED STATES OF AMERICA. UNITED STATES OF AMERICA ENVIRONMENTAL PROTECTION AGENCY. (2015) Clay Bricks [Online] Available from: https://www3.epa.gov/epawaste/conserve/tools/warm/pdfs/Clay_Bricks.pdf [Accessed: th August 18 2016].

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

UNITED STATES OF AMERICA. UNITED STATES OF AMERICA ENVIRONMENTAL PROTECTION AGENCY (2013) Clay Processing [Online] Available from: https://www3.epa.gov/ttnchie1/ap42/ch11/final/c11s25.pdf [Accessed: August 17th 2016]. UNITED STATES OF AMERICA. UNITED STATES OF AMERICA ENVIRONMENTAL PROTECTION AGENCY. (2015) Documentation for Greenhouse Gas Emission and Energy Factors Used in the Waste Reduction Model (WARM) [Online] Available from: https://www3.epa.gov/warm/pdfs/WARM_Documentation.pdf [Accessed: August 19th 2016]. UNITED STATES OF AMERICA GEOLOGICAL SURVEY. (2015) Mineral Commodity Summaries 2015. [Online] Available from: http://minerals.usgs.gov/minerals/pubs/mcs/2015/mcs2015.pdf [Accessed: August 25th 2016]. UNITED STATES OF AMERICA. UNITED STATES OF AMERICA GEOLOGICAL SURVEY. (2016) 2013 Minerals Yearbook-Germany [Advance Release] [Online] Available from: http://minerals.usgs.gov/minerals/pubs/country/2013/myb3-2013-gm.pdf [Accessed: August 20th 2016]. VENTA, J. (1998) Life Cycle Analysis of Brick and Mortar Products. Ontario: The Athena Sustainable Materials Institute. VOGDT, F. (2012) Lecture of Bauphysik. Technical University of Berlin. Berlin. Lecture held on October 18th 2012. WENG, C., LIN, D. and CHIANG, P. (2003). Utilization of sludge as brick materials. Advances in Environmental Research, 7(3), pp.679-685. WUPPERTAL INSTITUT. (2016) Benefits of resource efficiency in Germany [Online] Available from: http://wupperinst.org/uploads/tx_wupperinst/Benefits_Resource_Efficiency.pdf [Accessed: August 25th 2016]. YANG, F. et al. (2010). Study of Sticky Rice−Lime Mortar Technology for the Restoration of Historical Masonry Construction. Accounts of Chemical Research, 43(6), pp.936-944.

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

VI. Annex LIFE CYCLE ASSESSMENT OF CLAY BRICK PRODUCTION PHASE / STEP

PROBLEM

OBJECTIVE

SOLUTION

1 - Gathering raw materials

High energy consumption

Reduce energy consumption

Increase efficiency of mining tools; Use of renewable energy sources to supply part of the demand (e.g. solar and wind power)

Land consumption > deforestation

Reduce land consumption

increase efficiency of mining practices

Soil degradation

Reduce soil degradation impacts

Stabilize earth against run-off/erosion, renaturate/ let the soil recover

Social issues

Improve employees working environment / Reduce health risks

Increase working safety (equipment) / Comply with working laws / social/economical programs offering alternative lifestyles/sources of income (eg. through education)

Water pollution

Reduce water pollution

Use of less contaminant substances Treated wastewater

Transportation

Reduce CO2 emissions produced with transportation

Reduce distances/cluster production facilities / Use of alternative fuels (hybrid)

Energy consumption

Reduce energy consumption

Efficient lighting inside warehouse / efficient/industrialized storing techniques Alternative energies

2.2 - Raw material size reduction

Mechanical energy consumption

Reduce mechanical energy consumption

(fuel) efficient machinery / high quality tools withstand stronger force/can crush higher quantities/last longer

2.3 - Screening

Energy consumption

Reduce energy consumption

More efficient machinery

2 - Production

2.1 - Storage

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

Alternative and efficient fuels; make use of all sizes of gravel/do not waste any 2.4 - Forming and cutting

2.5 - Coating and glazing

Chemical substances added to “brick dough”

Reduce chemicals substances in water

Use less hazardous substances add safe/biodegradable chemicals / monitor impact on the environment (eutrophication vs. poisoning)

Contaminated wastewater

Improve wastewater quality

Install wastewater treatment on-site / Control wastewater quality / pass legislation for limit values

water consumption

Reduce water consumption

Use less water for cleaning/increase efficiency / closed loop of water system (treatment necessary) / change consistency of “mud/dough of bricks”? > less water is lost in evaporation / different production process? (e.g. use steam bath and high pressure instead of traditional method)

Energy consumption

Reduce energy consumption

Efficient/industrialized process: faster, more bricks cut at once / Low energy consumption machinery / different production process? (e.g. use steam bath and high pressure instead of traditional method)

Chemical substances added to water

Reduce chemicals substances in water / Add safer chemicals

Use of less aggressive, safer and biodegradable chemical substances / research alternative(physical) sealing methods?

Contaminated wastewater

Improve wastewater quality

Treat wastewater on-site / chemical recovery? / closed loop of water (re-)usage / More restrictive regulations / monitoring system for limit values

Workers health risks

Guarantee workers protection against hazardous substances

Enforce labour regulations (protective equipment) /

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

Regular inspection / make the production free of chemicals 2.6 - Drying

Energy consumption (50째C - 150째C)

Reduce energy consumption

More efficient machinery / Alternative fuels (e.g. solar heat) / climate adapted architecture of production halls (e.g. glass houses, adjustable low-tech ventilation) / controlled drying atmosphere / parallel instead of serial production > increased capacity of drying halls enable high production number while giving the drying process more time to proceed naturally / link to heat producing facilities (e.g. waste incineration plant)

CO 2 emission

Reduce CO2 emissions

Reduce drying process time Use of clean/renewable energy sources

Energy consumption (900째C - 1400째C)

Reduce energy consumption

Efficient - faster process

CO2 emission from burning

Reduce CO2 emissions

Alternative energy sources

deforestation

Prevent over-exploitation

Prevent illegal logging / monitor amounts / use alternative fuel sources / link to heat producing facilities (e.g. waste incineration plant)

2.8 - Packaging

Waste production

Reduce waste production

Reuse packages / Products with recycled and recycling content / incentivize

2.9 - Storage

Transportation

Reduce CO2 emissions produced with transportation

Reduce distances/cluster production facilities / Use of alternative fuels (hybrid)

Energy consumption

Reduce energy consumption

Efficient lighting inside warehouse / efficient/industrialized storing techniques Alternative energies

CO2 emission

Reduce CO2 emissions

Reduce distances / sell locally Use of alternative fuels (e.g. hybrid)

2.7- Firing and cooling

2.10 - Shipping

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

3 - First use building Construction

3.1 - Solid materials

3.2 - Fluid materials (mortar)

4 - Building use (Maintenance)

5 - Demolition

Packages

Reduce packages & disposal

Reuse packages / Recycle programs

Brick pieces

Better pieces cut

Wall layout / Reuse of small pieces / Add as aggregate to new clay bricks

Material loss

Reduce material loss landfill

Efficient construction process Lean construction techniques Wall layout, in order to plan the specific brick amount, size and type

Aggressive cleaning products use

Use of less aggressive products that conserve the coating

Use of natural/biodegradable products

Change of original characteristics

We canâ&#x20AC;&#x2122;t stop people from painting!!!

Promotion of natural colouring / appreciation / image campaign

Water consumption

Reduce potable water consumption

Include reused water (from the construction site) in the process

Health risks

Reduce health risks

Comply with working laws / use alternative (lime) mortar Periodically monitored

Chemical sealing application

Reduce chemical substances

Use of natural sealings? / Use of products that protect the brick quality / Intelligent building design with less exposure of walls to weather (e.g. oversize roofs) > no sealant necessary

Cleaning products use

Use of less aggressive / abrasive sanitizing products

Apply natural cleaning products

Antifungal products use

Use of less aggressive and environmental friendly products

Apply natural antifungal products / intelligent building design > no collection of water on the facade (e.g. by orientation towards the sun)

Disassembling and separation of bricks from mortar

Facilitate the process in order to obtain higher amounts of bricks able to be reuse

Use of lime mortar (easier to separate) / use new brick design that does not require any mortar

Not just another brick in the wall: improving the ecobalance of brickwork in Hamburg, Germany

Control quality

Comply with safe and higher standards

Monitored process Bricks classified and divided on-site according to the new use ( ex: structural, landscape, pavement)

Material loss Landfilling

Reduce the amount of waste

new use of bricks: pavement, landscaping, decoration, filling material

Potable water consumption for dust control and on-site cleaning

Reduce potable water consumption

Use water from Rainwater harvesting or treated wastewater / Use different brick design that does not require any mortar

Health risks

Reduce workers exposure to hazardous substances

Periodically monitored Use of personal protective equipment (e.g. against dust)

Energy and fuel consumption

Reduce consumption

Efficient machinery / use renewable energy sources

Energy and fuel consumption

Reduce energy and fuel consumption

Reduce distances

CO2 emissions

Reduce CO2 emissions

Use of zero CO2 emission vehicles

New 7 - Second use building

Same problems from step 3 ( First use building Construction )

New 8 - Second building use

Same problems from step 4 (Building use Maintenance)

Need structural reinforcement?

6 - Crushing (new 9)

Energy consumption

Reduce energy consumption

Efficient machinery Alternative fuels with less CO2 emissions

Waste productions landfilling

Reduce waste disposal

Use as aggregate Raw material for new construction elements

New 6 - Collection / Storage / Transportation