Green economy and innovation: compressive strength potential of blended cement cassava peels ash and laterised concrete

Abstract

This work highlights the incorporation of two locally available materials, cassava peels ash (CPA) and laterite, in concrete production for construction purposes. The abundance of these materials in West Africa paved the way for this study. The effect of partial substitution of cement with an agricultural waste (CPA) on the compressive strength of laterised concrete (LATCON) was investigated. Physical and chemical tests on CPA and laterite revealed them to have satisfactory characteristics for concrete production. A total of 192 cubic specimens of 100 mm dimensions were cast and cured by complete submergence in water for 7, 14, 21 or 28-day hydration periods, adopting a 28-day targeted strength of 25 N mm⁻² as the control. The ordinary portland cement/CPA and sand/laterite replacement ratios ranged from zero to 30% with a view to determining the best compositions matrix. The density and compressive strength performance decreased with increase in the CPA and laterite content. However, gradual strength development in the CPA-LATCON was observed as the hydration period increased. The 28-day density and compressive strength of standard concrete was 2 385 kg m⁻³ and 27.05 N mm⁻², whereas those of the 10% CPA+10% laterite sample (i.e. the best replacement matrix) were 2 322 kg m⁻³ and 25.57 N mm⁻², respectively. The strength of the CPA-LATCON (25.57 N mm⁻²) was higher than the targeted strength of 25 N mm⁻² after hydration for 28 days, which makes it suitable as a building material. As such, it can be adopted in the construction of simple foundations and masonry units as a reliable alternative to the scarce and expensive conventional materials for prime cost reduction in rural housing and development without compromising standards.