1
Muyinga_Burundi_2012
a cooperation between Brussels cooperation and Sint-Lucas sponsored by Vlir-Uos
(in)formation Burundi Project: a school for deaf children Type: pilotproject Location: Muyinga (Burundi) Client: ODEDIM Architect: BC-AS Budget: 20 000 â‚Ź Status: in construction Concept: 2012 Cooperation: ODEDIM Muyinga NGO, Satimo vzw, Rotary Aalst, Zonta Brugge, Provincie West-Vlaanderen, stichting roeping, Vlir-uos,
Faculty of architecture, KU Leuven, campus Sint-Lucas Brussels/Ghent.
6
8
Introduction
This booklet is a post script on the project (IN)FORMATION, built in Burundi from May until October 2012. The booklet is written and published by Eva Gheysen and Jasper Van der Linden, interns at Brussels Cooperation and master students from SintLucas University Brussels/Ghent. With an internship from VLIR UOS, the two Belgian students were able to participate in the project during two months in Burundi. This written work is an extension of the participation on site and together it stands for the content of the elective course “participation in an international project�. The booklet is considered as an after-reading of the project, from general outlines to the details. However the less, the publication could as well be regarded as a tool to inform external parties in earth architecture, building across borders and participatory projects in architecture.
Table of content
PROJECT FRAMEWORK _ _ _ _
Brussels Cooperation architects and studies Open source architecture Cooperation Planning
10 11 12 13
Reflection: the strengthening of various talents in participatory architecture Reflection: time-management in Africa
_ Aim of the project _ Context
A school. A library Muyinga, Burundi
16 17
Reflection: the consequences of development projects in Burundi Reflection: the advantages of informal community networks
MATERIALS & TOOLS
_ Materials 20 _Earth _Eucalyptus _Sysal _Tiles _Concrete Reflection: short-chain artisan production processes Reflection: job opportunities through participatory architecture
_ Tools of the trade 28 _Hands _Terstaram _Shovel _Sieve _Trowel _Test machine _Laptops
DESIGN & BUILD _ Masterplan Organization of the building site 39 _ Building plan 41 _ Finishing 42 _Furniture _Windows_doors _ Process 48 Reflection: the necessity of communication & cooperation
_ _ _ _
Earth research Earth conclusions Extra info Colophon
54 56 60 66
10
Brussels Cooperation architects & studies (BC-AS) is an architectural studio with an office based in Brussels. The leading architects of this studio are: Laurens Bekemans, Nicolas Coeckelberghs,Ken De Cooman and Wesley Degreef. Brussels Cooperation’s vision is an open, community-based approach that takes into account all the different actors in the design process and has a big belief in the spontaneity of informal architecture. Trying to build bridges between the formal and informal, they are becoming experts in solving problems of identity, locality and sustainability with an appropriated, lively architecture. In this perspective, the studio engaged already several context-driven projects in both the West and the South. It is in the practice of these on-site case studies that theory can be criticized, reflected upon and enhanced to develop a consciousness of a community’s needs in relation to architecture. The first elaborated case study, CS1: Open Structures, was a theoretical and fully research-based architectural model for the city Katanga in Congo. In this case study, the architects concretized a construction process that focuses on second-hand economies and end-users in accordance with a building’s energy cycle and product life cycle. (IN)FORMATION Five years later, CS2: INformation was undertaken as a graduate work at the faculty of architecture, KU Leuven, campus Sint-Lucas Brussels/Ghent. CS2 analyses the strengths and weaknesses of CS1 and converts these insights into a workshop in Muyinga, Burundi. Participatory processes, local economy cycles and social integration, by its use of materials, and by its organizational structure, are central in the second case study. More specific, the team is building a library as a pilot project that investigates the potential of the project for future development structures. The goal is to later on expand the infrastructure with the construction of a boarding school for deaf children. In this publication, CS2: Information will be further revealed. By explaining material specifications, exposing the work process, formulating questions and sharing knowledge and experience, we hope to awake a positive mind set towards informal architecture and the need for a total architectural integration in the cultural context.
Case study 1: katanga, congo “Can we design hardware like how we design software?”
Implementing Open Source thinking to humanitarian architecture Social integration In a very informal and oral Burundian culture, deaf children are excluded from stories, information, exchange and education. The school will integrate its deaf students into broader society by the outwards organization of a library, ateliers and a polyvalent hall. Local economy cycles Exploring the potential of earth architecture, the library is totally built with local resources. The earth is excavated from the site, remixed with other earth from a nearby quarry, and compressed using manual tools. The rest of the material is locally produced or, if not possible, locally bought. All labor is by hand and local, providing skills and income for the inhabitants of Muyinga. The “material of the poor” is in this exemplary building used as a suited building and finishing material, within the budget of local community projects. Participatory processes The organization of the library happens through the local partner, and creates 1 permanent self-sufficient job. The board of the library includes directors of neighboring schools, facilitating contact and cooperation between the future deaf students and the hearing students.
12
Cooperation
For this project, the architects of Brussels Cooperation worked in association with the NGO and diocese of Muyinga (Odedim). Together they want to stimulate the promoting of the construction of integral development in Burundi, with a specific focus on the development of educational structures (schools). Satimo, a small Belgian ‘vzw’, gives financial support. Besides that, the project is closely connected to SHC, an association for deaf people in Europe. Also Rotary Aalst, Zonta Brugge, Province of West-Flanders, Abdijschool Zevenkerke are given a worthy mention for their financial support. Finally VLIR-UOS in combination with the faculty of architecture of KU Leuven, campus Sint-Lucas Brussels/Ghent was the academic partner of this project.
the team
vlir-uos interns
other interns
brussels cooperation architects
The planning May Vision on masterplan
June
July
Check-up of local materials and techniques
execution plans
Measuring+ quatation
Choice of exact placement Earth tests
August
Finishing the drawing for the entire school
Sept
Oct
Execution plan of the entire project + fundraising
management and organisation of construction site
free site + digging in
Foundation + vertical structure
Roof+ interior volume
Electricity
Finishing
Structural research of the colomns and the roof
Documentation
Nicolas Coeckelberghs, architect Laurens Bekemans, architect Sebastiaan De Beir, architect Ken De Cooman, architect Sarrolta Huttl,
architect intern
Hanne Eckelmans, Eva Gheysens,
architect intern
architect student
Jasper v.d. Linden, architect student Inez v. Roosbroek, intern
Reflection: the strengthening of various talents in participatory architecture Since several years now, participatory design has taken a more prominent role in architecture. Some of these participatory initiatives are very innovative but often fail to translate the theory to practice. Brussels Cooperation has proved that also in practice the participative approach can work. Not only totally depending on and cooperating with local work men; BC also involves students, interns and young architects in the projects abroad. The working together with different people has proven to be a very fertile collaboration. Looking back on the project, almost no complications occurred in the participation process. Even better, the participants were all eager to work together and also external groups showed interest and admiration. However, it must be said that good leadership is necessary for an efficient organization of all the parties involved. The architects of BC have taken this leadership very serious and were able to not only bring the various forces together but also let them strengthen one another.
Reflection: time-management in Africa In all architectural projects time management is crucial. The planning of a project in the South demands a particular approach. When working for the first time in a new context, local techniques, working attitudes and expectations can vary from the ones you are familiar with. The time schedule needs to be more flexible and resilient to be able to adapt to sudden changes and surprises. In the case of the (IN)FORMATION project, we soon noticed that the time pressure we are used to work under in the West, is totally not present in the spirit of the people of the South. The time schedule we first had in mind, did not take into account the local mind set. Although we could sometimes push the workers to work faster by giving bonuses, it is impossible to change a mentality. We certainly learned that, in regions where people are used to a lower rhythm of life, the time schedule needs to respond to that.
16
Aim of the project A school. A library. The target of the (in)formation project is to build and start up a school for deaf children. But for the summer of 2012, the target was to build just the library. It’s seen as a pilot project to get familiar with the local way of working, experiment with the materials and their possibilities. Materialwise the aim is to avoid concrete (imported and thus expensive, giving resources to place of origin - Dubai and China) nor fired bricks (because of deforestation). This gives us the possibility to use local materials in a contemporary way for bigger infrastructure (earth as a building material for school and public space), giving back pride and self esteem to local community. This also means working with local workers who have knowledge in earth building, providing financial resources and work with local community (instead of working with contractors, who come from Bujumbura or even Rwanda). A last aspect is to link construction process with local micro-economies and the startup of a Community Based Organization (CBO) on a long term, stimulating the rise of small or medium enterprises (SME’s) out of these structures.
Burundi, Muyinga The library is built on an inclined, woody terrain of 14.000m² on the hills of Muyinga. The town Muyinga is located in the North-East of Burundi, a small country situated in the Great Lakes region of Africa. The province Muyinga is adjacent to the borders of Tanzania (East)and Rwanda(North). Geographically isolated, facing population pressures and having sparse resources, Burundi is one of the poorest countries of the world. With 8.5 million inhabitants, the population is still reduplicating every thirty years. Fifty percent of these inhabitants are aged under fifteen. Ninety percent of the economy is based on agriculture. The people are totally dependent on the merits of the land, which are very low due to a lack of fertile grounds, inadequate techniques and no support. More than half of the households are not in the possession of the basic needs to survive. Another critical issue is the high percentage of analphabetism in Burundi. Although the number of students is rising and the government is making efforts with the distribution of didactic material and the training of teachers, only one third of the pupils finish school.
RWANDA
Cibitoke
Muyinga
Ngozi Kayanza
Karuzi
democratic republic of the
CONGO
Cankuzo Muramvya
Bujumbura Gitega Mwaro
Ruyiga
united republic of
TANZANIA
Rutana
Bururi Rumonge
Makamba
Nyanza-Lac
0
10
20
30 km
map of Burundi
Reflection: the consequences of development projects in Burundi
In advance of our departure to Africa, we were warned by the diplomacy of Flanders that Burundi is a country that still encounters dangerous situations in the aftermath of the civil war between the Hutu’s and Tutsi’s. Travelling through the country, we noticed visible signs that Burundi is indeed only just awakening from a terrible past. However we didn’t witness any real danger. The people envision the future with a positive attitude. The willingness to strive for a more prosperous environment shows us that Burundi is a country were development projects are well received and can contribute to the people’s well-being. As a Belgian partner working in Burundi it takes psychological empathy to understand the expectations of the local people. They know the development workers come to Burundi to help them but it’s hard for them to understand why we do so. Some moments we were made clear that they found it more than logical that the ‘rich’ came to help. Gratitude was sometimes far away, but only because they don’t realize the principle of give-and-take, and in this case the give-and-give. It is clear that they have a somewhat distorted world view of South versus West, which cannot be blamed since they are not informed. One must be very attentive in this case because it would be wrong if the locals expect us to help. It becomes dangerous if they passively rely on the interventions of the Western society and get totally dependent on us. The development countries must also believe in its own force to become a powerful union instead of the weaker underdog. That is one of the aspects why participation projects are a very good solution in this context. Instead of intrude their property and take over, responsibility is demanded from them as well. The locals are given a respectful position in the debate and are involved in the discussion. In that way, we show them that their opinion is important and that they can give direction to change.
Reflection: the advantages of informal community networks
A positive aspect of community-based projects is the fact that they are indeed based on the cooperation of members of a community. We surely acknowledge the fact that in the small villages in Burundi people can really rely on each other. In contrast to the Western business, where every person relies on himself, the Burundian people are very open and helpful. Living in a non-consumption society, people are used to borrow from each other, work together to achieve goals and support each other. Because of the very open (social) structure of the town, there exist many networks between the people of Muyinga. In certain phases of the construction we thought to cancel certain aspects of our plans since they seemed practically impossible but thanks to the open mind and creative thinking of the locals, we always found a way to achieve our ideas.
20
MATERIALS
EARTH
target: brick making
Earth “from mother nature” After an extensive material research in relation with the context, it was decided to use compressed earth bricks (CEB) as the main material for the construction of the building. The CEB building technique was often used during the nineties but lost its glamour during the years, until architect Francis Kéré [1] made use of it again in noticeable projects in Africa. BCs always had an interest in this raw material and believed in the potential of it. The creative Library project in Burundi, gave the opportunity to fully explore earth architecture.
22
EUCALYPTUS
target: roof construction
Eucalyptus “wood; the strongest, the reddest� The load bearing beams that are supporting the roof are made of eucalyptus wood. This beautiful red wood is delivered by a supplier in Muramba, a village nearby. As a client you go to the plantation and you pick out the trunk you like. They cut and prepare the beams and additionally they plant a new tree for each one they cut.
SISAL
target: giant hammock
Sisal “rope; from plant to hammock” The process of net-making is the following; 1. walk fifty meters from the building site to chop of some leaves of a Sisal plant. 2. strip the leaves until only the vessels are left. 3. wrap a bundle of these vessels together to have a small rope. 4. weave six of these small ropes together to have a real rope. Add two thin metal wires to this weaving to have the needed strength. 5. Repeat step 1 to 4 until you have enough rope to make a net. From plant to net in five steps, it is a magnificent ‘only in Africa’ experience!
24
TILES
target: roof finishing
Tiles “local quality product� The roof tiles are made in a local atelier in the surroundings of Muyinga. The tiles are made of clay and consequently baked in ovens. After baking, their color renders beautifully vague pink, the same color as the bricks. Each roof surface consists of around 1400 tiles. After calculating the resulting weight of the tiles, the thickness of the beams of the roof could be defined.
CONCRETE
target: column insides
Concrete “when it’s the only way out” For increasing the stability and taking no risks, it was decided to use a small amount of cement in the construction. Because it is preferable to build a recyclable structure, the cement and earth were consciously kept divided so the earth part easily can be reused in the future. In this situation the brick masonry is used as ‘lost’ formwork to cast the concrete in. This results in an earth structure with a thin concrete skeleton that is hidden.
Reflection: short-chain artisan production processes In Burundi, a country with very little industrialization and import, almost everything is locally made by hand. When searching for resources for the construction (materials, tools, specific gear‌) we had to search for it in our near surroundings. Sometimes this seemed very difficult. We for example sought a long time to find rope to build the hammock with. We couldn’t find any shops that sell it. For a moment we considered to order rope from Tanzania, where they did sell it, but this seemed a little far-fetched. After approaching many people to ask where we could buy rope, we were directed to a talented man that lived in Muyinga and who could produce rope from plants. No transport was needed, no exhaustive production processes were demanded. All of us admired this easy, down-to-earth, artisan production. Next to a fascinating simplicity, the short-chain production processes in Africa were really an eye-opener for us, Western architects. Heading to a more ecological way of living in the 21st century, other continents can learn something from this. We need to add here that the artisan production of material is less precise than the industrial production method. It is logical that slight differences can appear in dimension, color and quality of the product. This can sometimes give inconveniences that should be considered in advance.
Reflection: job opportunities through participatory architecture A factor that we underestimated in advance was the positive effect of job creation as a result of the building of the library. Before the start of the works, the idea was to give job to twenty crafts men. During the works, this amount was increased up to sixty people. Every day locals stepped by at the construction site and asked if we had more jobs for them. It was very remarkable for us how much these people wanted to work but didn’t find a job. Due to the current economic situation in Burundi, most of the Burundian people are out of job and have to find other ways to survive. Development projects on participatory basis can have a big influence on this matter. Seen the potential of job creation these projects bring forward, it seems worthy to explore these advantages. In future projects it could be useful to further develop the participatory model in means of an employment plan.
28
TOOLS OF THE TRADE
HANDS
target: everyting, really! amount: up to 140 (2X70)
hands “replacing the machine� The most obvious, as well as the most important tool. As there is no electricity available on the construction site, the only option is to use menforce. A big amount of men and woman were working on the site; monday-friday 8am-5pm. Because labour is very cheap in Burundi (~1,2euro/day) and the unemployment very high, it is an interesting solution to rise the number of labourers on site in order to get a quicker result.
30
“Salvator is nice. Lovable. Soft. No-one speaks about what one has lived through during ‘the crisis’ (Rwanda-Burundi genocides). But sometimes, my Western eyes envision some strange long-worn burden, a pain maybe, which has shifted in a soft thankfulness for the non-crisis mixed with tiredness of the past. A constant light sigh. Life’s not good, but good enough”
32
TERSTARAM
target: earth bricks production amount: 2
Terstaram “made in Belgium� These 2 machines were probably the most advanced tools on the site. Dating back to the eighties, they were spread all over Burundi. We were lucky enough to find some of these intactly. The Terstaram machines produce blocks of 29x14x9cm that are very similar to the bricks we know in the West, apart from the fact that they are not baked. The basic principle is the following; make a good earth mix, put the earth in the mould of the machine and press it together. This delivers a finished stone. Four people are constantly producing stones, up to 1100 stones/day. The conventional houses of Burundi are made of earth blocks that are produced by the Hydraform machine. These blocks however, have restricting properties in way of strength and therefore are mostly only used as filling instead of load bearing elements.
SHOVEL
target: moving earth amount: +-25
Shovel “oldschool, but so reliable� A big amount of earth needed to move. As the site is situated on a rather steep hill, big parts needed to get flattened. Because moving earth by hand is very labour intensive, more critical thinking about smart usage of the earth and moving them immediately to a good spot became necessary.
34
SIEVE
target: preparing earth amount: 1
Sieve “selfmade improvisation� This set-up for a sieving system was necessary to produce earth with a certain particle size. The total earth mix contains a specific ratio of particle sizes in order to work together as one solid brick. The sieving grid was brought from Belgium and the system was put together with some trial and error. The final outcome turned out to be the most practical solution for the workmen.
TROWEL
target: mason the stones amount: +-20
Trowel “key tool for masoning� Burundians are crafted masoners. Although both the bricks and the mortar consist fully out of earth, the walls are put up pretty similar to any other.
36
TEST MACHINE
target: calculate amount: 1
Test machine “self made for the win� To check the strength of the earth bricks, we used a self-made installation with steel bars and a flat panel on top. On this surface weights can be put, each time more, until the brick underneath breaks.
LAPTOPS
target: design, communicate amount: 7
Laptops “technology invasion” We’re not going to lie. Our main tool is still the laptop. Making the design of the building, detaillings, calculations,... Most of it was done from behind a screen, as long as there was electricity. Although the computerdesign made it possible for us to work in an exact and efficient way, a lot of things change when arriving on the construction site. A good balance between our well-known way of designing and smart fieldwork is a must.
38
DESIGN
Site Masterplan The site has been measured entirely in order to fit the future masterplan into the hilly site. A sketchversion of the plan for the entire school has been made. So far, the library is the only part that has been realised (front-left of the picture). Public-private The school was meant to be fully open towards the street. Unfortunately the western idea of happy sunny squares is not really context-driven and it was advised to provide fencing. This was solved by lifting the school 130cm higher than street level to create a subtle border. The uphill terrain has been terraced to create playful variations in height and trace the different school yards (public square, intimate play ground, school yard for pupils...)
40
Building plan The total building consists of an open walkway which facilitates the entrance to the rest of the site. It blocks the sun and creates a covered outside space. Adjacant to this walkway there is the library on the one site, a square on the other.
Library interior The internal library space is divided in two areas by means of height difference. In the larger area a polyvalent table forms the centre of the room. The smaller part, positioned at street level, is a playful area where the children can read and play.
Hammock The lower-situated space is very open and high. A mezzanine consisting of a simple net, reaches from the ridge of the roof to an intermediate level. Thanks to the transparency of this net, the visual connection between the main library area and this higher placed spot is preserved.
Roof The roof structure is a double, asymmetric gable roof and has a cantilever of 150 centimeters to prevent rain flow on the faรงade (erosion). At both sides of the library the horizontal beams of the roof run from interior to exterior, supporting the overhanging roof. This cantilever articulates a pathway in line with the library and generates shading.
42
planches: 440X100X1mm planches: 440X100X1mm
chaise.15pièces chaise.
colonnes: 40X40Xxmm
15pièces
colonnes: 40X40Xxmm
40mm
40mm
10mm
440mm
10mm
440mm 100mm
100mm
855mm
100mm
100mm
100mm
895mm
10mm 100mm
100mm
440mm
855mm
100mm
40mm 40mm
320mm 400mm
40mm
section
100mm
895mm vue frontal
10mm 100mm
440mm
40mm 40mm
40mm
section
320mm 400mm
vue frontal
Furniture In total 9 tables, 15 chairs and a total of 12 different boxes were created. Part of the furnitureconcept is a universal box –“poefje”— that can have diverse applications and functions. The module can be used as a seat, a container to stock books, a ladder to reach the highest books, and so on. The “poefjes” are small sized seats which can be placed in the bottom bookshelves and taken out when more than the basic furniture is needed. This way, the library possesses of a set of seats with various sizes, ideal to set up a movie theatre.
44
Windows & doors The doors and windows are fabricated by local craftsmen on the needed dimensions. They are made out of steel, wood and glass for the windows. Having the doors and window shutters closed, the building becomes quite vandalism-free. But when opened there is openness from top to bottom.
46
Process
From foundation to roof structure in 1,5 months
48 Work process
As the finishing of the roof needed to be ready before the start of the rain season, the different construction phases of the building were well scheduled. In order to work on time, improvisation and extra working time was needed. As everything went the African way, one can not rely on the promised deadline. So as long as you count this in, everything will end up okay. That’s how it rolls there!
Quote from ‘CEB PRODUCTION’. August 5th, 2012
“
In the beginning the average amount of bricks produced in one day was around 900 bricks. However, to produce enough bricks during a production period of four weeks, a daily production of 1200 bricks is requested. We now encourage our workers to fasten up a little by giving them a bonus when they reach 1200 bricks a day. The sheltered storage space where the bricks slowly dry is getting more and more filled with beautiful red bricks…
“
Quote from ‘IT IS RISING QUICKLY NOW’. August 24th, 2012
“
And yeah, we’re fighting back! The working forces on site have been almost doubled. Right now we’re giving job to an incredible amount of 64 craftsman and workers. But also the architects haven’t been sitting on their lazy ass; working two weekends in a row to try finishing all the needed details in time. If not the workers might evolve quicker than we do…
“
Quote from ‘CEB PRODUCTION’. August 5th, 2012
“
After that busy week, life in Muyinga went on. Lately it has been cloudy and three days of rainfall were even precast during this dry season. Still though, we run out of water more and more during the day. For that reason we cannot flush the toilet, what sometimes results in rather nasty activities like cleaning out stuck toilets… The lack of water is probably also influenced by the fact that we now already live with 8 people in the house. Jasper, the other intern from Sint-Lucas University has arrived along with Inez, an interior architect and graduated student from Sint-Lucas. Now our group is complete and the house is fully booked.
“
foundation making, july
first electricity, august
50
Reflection: the necessity of communication & cooperation
During the elaboration of this pilot project, we learned how important it is to have good communication and coordination. The communication on site went actually very well. We were privileged to work with Salvator, the contractor of the project and a very experienced man who has already accomplished several constructions in Muyinga. With his architectural background, Salvator easily understood the architectural concept and ideas of the architects. Very often he was included in the decision-making process since he perfectly knew what was possible in the given context. Next to that, he perfectly speaks French and Kirundi, and thus fulfilled a prominent role as translator between the architects and the executioners. It needs to be mentioned that language deficiencies cannot be underestimated. The efficiency can really lower if the communication slows down. We were therefore very pleased with Salvator’s presence. It is very clear that in cooperation and development project as such, a local intermediary person is indispensible. This person’s job is to communicate between the local participants and the development workers, to share his knowledge of the local situation with the workers from abroad and most of all to act as a guidance for the local people in name of the architects.
54
Earth research Before the start of the brick production, a certain earthmix needs to be defined. Therefore an analytical research is made. This means that the earth gets examined towards its given particle sizes. Based on these granulometry curves a certain mix gets chosen. This mix was used to produce compressed earth bricks for the library. Finding feasible earth Different testing pits were dug on the site in order to check the different layers of earth. One of the pits, positioned under the future library, showed a very sandy earth with a big amount of white stones. This same earth type was present in three other excavations on the building site. This type of earth is not the best earth to produce CEB blocks with. Luckily, thirty meters left of our site we discovered another type of earth. Still, after doing tests with samples of the latter type, this type of earth wasn’t perfect. An addition of clay was needed. We found this clay earth on another construction site where we were allowed to take all the earth needed to produce the bricks. After moving 150m³ of earth with men and bags 150 meters downhill, all the components for the production were gathered. Now we could start
Testing the earth One of the preliminary tests is the linear shrinkage test or Alcock’s test. It is performed with the help of a wooden box that has to be exposed to the sun during three days or put in the shade for seven days. The results showed only little shrinkage. Next we did a grain-size distribution analysis. Some kilos of raw earth, eight sieves, two pans, a 500ml bottle, an accurate balance and a brush are the ingredients for this test. First, the earth has to be cooked to evaporate the water out of the earth. For the first test we used two kilo of dry earth from the hole close to the building site. We sieved out the gravels and measured the dry weight of those grains. For the clay earth the test is the same except water is added to wash out the silt. The leftover water then is boiled to collect the grains that passed through the sieve. These grains then undergo the same procedure but with a sieve with smaller mazes. Everything that passes through the final sieve of 0,08mm is pure clay and silt. Both the earth of our own site as the earth from the site uphill contained around five percent grains. Fifty percent of the two earth types contained gravel bigger than 5mm. These big particles have to be sieved out on the building site for the production of the CEB bricks.
56 With a sedimentation test you can continue the grain-size distribution for the particles smaller than 0,08mm. The principle of this technique is the fact that particles in suspension of water tend to fall at different rates. The largest grains settle first, while the fine ones last. For this test you need two 1000ml flasks, 2 hydrometers, a thermometer and some liters of distilled water. To make a dispersant you mix bicarbonate with soda (one gram per centiliter). The test starts by mixing 20g of the earth with 15cl of the dispersant and 125cl of distilled water. After mixing this in one of the flasks for 15 minutes you have to let it rest for 18 hours. One day after you have to fill the other flask (which will be the reference flask) with the same amount of dispersant. In both flasks you then add low-PH water. Thereafter you mix this flask with the earth. Then place a hydrometer in each recipient. Changes in density are measured at regular intervals at a given height. The results of the test give you the exact amount of clay in the soil. To check the strength of the earth bricks, we used a self-made installation with steel bars and a flat panel on top. On this surface weights can be put, each time more, until the brick underneath breaks. It became clear that, unfortunately, we had to add cement, since the earth mixture was not optimal. We then had to make a decision: or using a percentage of cement in the brick itself, or making a concrete body with the masonry as lost formwork to cast the concrete in. We favoured the latter method since in that manner half of the column is recyclable.
Earth Conclusions on material feasibility After gathering experience with the chosen earthmix, in combination with intuitive analysis we can make several remarks. _The granulometric curves are just an indicative test, and do not provide secure mixes. Also, normally these tests are done by experienced people in a well equipped laboratory. It could be that the sedimentation test was not secure. _Our initial intuition that we needed more clay added to the site earth’s mix was faulty. The earth on our site contained a lot of clay, the type of earth feasible for adobe’s. The earth we took from another site was clayey silt. The combination of both is does not give such an interesting mix, as we still have just small particles, not giving strength or structure to the mix. _We need to add some structure, this can be managed by adding sand. _The amount of water added to the earth mix was too low. Due to this this the clay was not able to become soft and work as a binder between the bigger particles. Based on these remarks, some new quantitative analyzes were done. These confirmed the above intuitions. Several CEB’s composed of different mixes with different water content during production were tested on flexion and compression, resulting on some final conclusions.
The compressed earth bricks for the library will need a covering layer in order to protect it from erosion and porosity of lateral rain effects. In the future good quality control during the production is crucial; checking the amount of water and the level of mixing is key.. In combination with adding sand to the existing mix, it is possible to create blocks that are in same league as those with the existing mix stabilised with 3-4 percent of cement, in terms of compression and flexion force, but not in terms of erosion resistance. Intuitively, based on the fact that site soil is clayey, adding lime to the mix can also deliver very stable stones. The high amount of clay will react with the lime. But in order to make this reaction work, a precise production process is necessary. And that’s quite a challenge on the building site we’re dealing with. Conclusively, we should realize that totally manual CEB presses are normally not suitable to make unstabilized CEB’s for load-bearing or exposed walls. With proper architectural design, combining stabilized and unstabilized CEB’s should be the way to go to construct a loadbearing earthen structure without the use of concrete columns.
58
60
Communication and more info on the project
on-site video’s, on vimeo.com, on Brussels Cooperations account
exposition (november 2012) Brussels centre
website BC-AS, www.bc-as.org
62
64
Grasping the future It is not possible yet to publish an exact schedule concerning the future of the school. There is always a high factor of awaiting in this kind of small scale development projects. Much has to do with the money flow and the cooperation between all the different partners. It needs to be taken into account that this whole project is financially a zero-operation for the architects and the pro’s and contra’s need to be balanced to see if it is reasonable to keep on working on this project. Brussels Cooperation however is willing to resume the project as soon as new financial funds are collected.
66
Project participators: Laurens Bekemans, Nicolas Coeckelberghs,Ken De Cooman, Sebastiaan De Beir, Wesley Degreef, Hanne Eckelmans, Sarolta Huttl, Eva Gheysen, Jasper Van der Linden, Inez Van Roosbroeck Photographers: Nicolas Coeckelberghs, Jasper Van der Linden, Ken De Cooman, Olmo Peeters
Sources: [1]Architect Franis Kéré, 2012, ‘http://www.kerearchitecture.com/’ Kavumbagu V, maart 2009, ‘Contexte socio-politique et économique au Burundi’ BC-blogposts, 2012, ‘http://brusselscooperation.be/bcstudies/?cat=1’ Rigassi, Vincent, Guillaud, Hubert et al., Blocs de terre comprimée: Volume 1,2. Manuel de production, 1995: Eschborn. Houben, Hugo et al., Compressed Earth Blocks - testing procedures, Craterre-EAG/ENTPE/CDE, Bruxelles: 2000. Houben, Hugo et al., African Regional Standards for Compressed earth blocks, dans CDE Guides ‘Technologies Series’ No. 11, compressed Earth Blocks - Standards, Craterre-EAG, 1998: Grenoble.
Editorial: Jasper Van der Linden, Eva Gheysen. Master students at the faculty of architecture of KU Leuven, campus Sint-Lucas Brussels/Ghent. Academic coordinator: Nele Stragier
December 2012
68