The residual peels from a plant called cassava, a woody shrub that is a staple food in several African countries, can become a valuable element for the construction industry.
The plant is grown increasingly across Africa, with Nigeria by far the largest producer worldwide. The amount of waste from the plant, however, is also growing in quantity and since it currently has no use, it can potentially cause environmental problems.

In a joint project by Bundesanstalt für Materialforschung und -prüfung (BAM), a senior scientific and technical federal institute in Germany, and Dr Kolawole Adisa Olonade from Obafemi Awolowo University, it is planned to reuse cassava residues in three ways. Firstly, residual starch can be recovered and used as a rheology modifier for concrete and building materials. Secondly, residual peels can be used as fuel, for example for firing bricks. And finally, the ash from the combustion process can be used as a sustainable supplementary cementitious material.

This research idea received the German African Innovation Incentive Award, together with incentive funding of 150 000 euros.

The project, “Low-carbon livelihoods – cassava residues for performance materials (local care)”, started on 1 January and will run until April 2020. The aim is to technically evaluate the substances obtained – in particular, how much carbon dioxide (CO₂) can be saved, which new value chains can be created through the valorisation of agricultural residues, and which framework conditions are required to ensure safe construction and high-quality infrastructure.

Awareness further needs to be raised about the fact that agricultural residues are as much suitable for high-performance building materials as established residual materials from metallurgy or coal combustion. Thus, a lecture series will be held in Algeria, Cameroon, Kenya and South Africa to disseminate the results. In the final stage, a real building made from cassava bio-concrete will be installed in Nigeria.

Full thanks and acknowledgement are given to BAM for the information used to write this article.

Caption main image:
From the left: Wolfram Schmidt and Kolawole Olonade in BAM’s concrete laboratory, together with Nsesheye Msinjili and Stefan Schacht.
Courtesy of BAM, Division Technology of Construction Materials

If you enjoyed this article, please join other discussions like this on http://www.facebook.com/buildinganddecor, http://www.twitter.com/buildingdecor and https://www.linkedin.com/showcase/10172797/, and sign up for our newsletter: http://www.buildinganddecor.co.za/register/.