Laterite Based Low Carbon Binder for Circular Economy in Yaoundé, Cameroon

An efficient and affordable low carbon binder, based on Yaoundé local excavation earth, that achieves sufficient mechanical strength and water resistance for rendering applications has been formulated. Blends of Portland cement (PC) and laterite calcined at 750∘C (CL) with varying weight ratios were investigated. The pozzolanic reaction was detected when replacing up to 70% PC by CL. The research investigated laterite sand mortar formulations, with varying proportion of fine particles. The strength of mortar pastes containing 40% and 100% PC in the binder reached the same level. The compressive strength increased with decreasing proportion of fine particles, and reached the maximum value of 10.2 MPa when the laterite sand grain size is larger than 100μm. The water absorption tests by capillarity showed that the formulation belongs to class Wc2 mortar, for all the laterite sand granulometries. The water absorption by capillarity coefficient decreased with increasing fines proportion : the highest value of 0.051kg/(m2.min0.5) was obtained when the laterite sand contains no fine particles. Furthermore, the study explored the reuse potential of the grinded mortar : the fines showed pozzolanic properties and can be used as supplementary cementitious material, and the largest particles are suitable for lime stabilization.