Cement-free Concrete
The ETH spin-off Oxara developed a low CO₂ additive technology, which, when added to excavation materials, enables the advantageous production process of mixing and casting to produce a cement-free concrete. The earthen concrete is 20 times more eco-friendly than ordinary concrete and can be used as non-structural or low load-bearing elements in 2-3 story buildings. 45 million tonnes is the amount of waste excavation material that goes to landfill in Switzerland each year without the possibility of reuse. Oxara uses the landfill material to produce a poured earth concrete and also non-fired bricks. Once it is industrialised, the technology constitutes a straightforward solution for sustainable construction and affordable housing.
The construction industry is facing major challenges, including scarcity of natural resources, especially sand and CO₂ emission due to large cement production. Finally, there is an increasing demand for affordable housing worldwide. Meanwhile, billions of tons of excavation materials are landfilled per year. This waste material is currently unused and occupies a large volume of space.
Oxara transforms the excavation material into a valuable resource and produces sustainable building materials using a unique admixture technology developed during Oxara’s founding member Gnanli Landrou’s PhD at the chair of sustainable construction at ETH Zürich. On one hand, one additive technology Oxacrete(R) allows us to cast the excavation materials in fresh state using few amounts of water and similar concrete infrastructure, then accelerate the hardening over time in order to remove the formwork after 1 to 2 days. On the other, oxabrick(R) allows to produce brick at lower temperatures or sometimes substitute cement in stabilized earth brick to produce high-performance products. And when industrialized, both products constitute not only a sustainable solution for future construction but also a solution to the affordable housing problem. Oxara products have up to 80% CO₂ reduction compared to market products and therefore enable the reduction of global CO₂ emissions. Through the use of excavation earth and sludge, we will also achieve a reduction of construction waste and sand. A derivative of the Northern Togolese language, Lamb-Kabyè, Oxara means “Gathering and Community.” Oxara wants to bring the actors of the construction ecosystem together to create an innovative and sustainable industry collectively and to achieve its vision of housing for all.
