Manufacture of lightweight clay bricks with improved thermal insulation properties via the incorporation of spent shea waste

Abstract

An effective environmentally correct disposal option for spent shea waste is remarkably constrained by many factors regardless of the disposal method adopted hitherto. Dumping of spent shea waste in farmlands or its landfïlling have serious long-term ramifications to environment. Besides, it cannot be openly burned without violating international treaties on global warming issues. For this reason, we incorporated spent shea waste into brick making clay towards the manufacture of lightweight clay bricks with improved insulation properties. In this regard, bricks were prepared under various sintering conditions by replacing 5, 10, 15 and 20 wt.% of the clay material with spent shea waste. The results show bricks fired at 1000 °C with 15 wt.% spent shea waste incorporation is most optimized manufacturing condition. These bricks demonstrated a 13.82 wt.% reduction in weight, compressive strength of 6 Mpa, water absorption of 15.95 % and a beneficial reduced thermal conductivity of 0.31 W/(mK), which translated to about 58.06 % increase in thermal insulation relative to the reference brick samples. This research has therefore provided convincing evidence on the possible widespread valorization of spent shea waste in manufacture of lightweight clay bricks with improved insulation properties. Hence, an ecofriendly disposal method of spent shea waste.