Boosting affordable housing with cementless blocks
The market demand for construction materials is tremendous in developing countries due to a growing population. To tackle the disadvantages of hollow concrete blocks and burnt bricks Oskam , LEVS and TNO are developing a new kind of cementless compressed earth block for housing. These innovative blocks only require local resources and no cement, thus lowering the environmental footprint and at the same time achieving the required price point and performances required by the local market.
Disadvantages of current blocks and bricks
The current demographic boom in Africa has caused a rapid urbanization and increase of housing demand. One of the most common obstacles African markets are facing is a shortage of affordable and sustainable housing. The most commonly used building materials in African cities are concrete hollow blocks, a non-loadbearing cement based material that requires an additional loadbearing structure made of even more cement and steel. In addition to that, because of their low thermal mass hollow blocks or bricks are not suitable in warm African climates, creating living environments that are comfortable only with the use of air conditioning, powered by non-reusable energy sources.
In some countries, burnt clay bricks are an alternative to concrete hollow bricks, however, the downside is that they require temperatures higher than 1000°C in order to obtain good quality and strength allowing durable multi-story housing. Industrial brick making therefore has high energy costs and CO2 emissions, while traditional brick making in clamps using firewood and causing deforestation often does not reach 1000°C as such producing low quality bricks.
Compressed Earth Blocks
Compressed earth blocks is an alternative technique, reinterpretation of traditional earth blocks (adobe), but using new technology. The result consists of uniform building blocks, compressed from clay-retaining earth, suitable for use for load-bearing and non-load bearing walls. The compressed earth blocks are not fired and not hollow so that they have a unique low CO2 footprint, while preserving moisture-regulating and heat-accumulating properties. The earth can usually be extracted locally (even directly from the building site) at very low or no costs. OSKAM and LEVS have a long partnership in developing compressed earth block technology which led to creation of a mobile hydraulic machine in 2007. It has since been in widespread use across many European, African and Middle Eastern countries. Today the biggest obstacle is the price and environmental effect of cement which needs to be used as a binder (5-7% of material, but 50% of the price). Finding a locally produced alternative to cement, the price of blocks will drop substantially as well as its environmental footprint.
Towards innovative substitute for expensive cement
OSKAM, LEVS architects and planners and TNO, have a vast experience on developing sustainable building alternatives. We believe that, in order to address this ever increasing need for housing and at the same time support local economies and income, more buildings should be made with high quality blocks produced using only local resources, at low temperatures and stimulating local labor. In this project, we verify the technical and economic feasibility of developing a new kind of Cementless Compressed Earth Block, which would only require local resources and no cement, at the same time achieving the required price point and performances required by the local market. We conduct this study in Senegal and Ghana. This project is recently approved and financially supported by RVO in the SBIR Circular innovations for fast growing cities and we will deliver our results mid May 2020.
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