EFFECT OF PROCESS RICE HUSK ASH ON THE STRENGTH OF LOAD BEARING BLOCK

Cement production contributes significantly to environmental pollution through the release of carbon dioxide during calcination and energy consumption in manufacturing which is hazardous to the ozone system, human, plant and animals. Based on this, this study investigated the effect of processed rice husk ash (RHA) on the strength of load-bearing blocks. The research aimed to determine how partial replacement of cement with RHA at different percentages influences the density and compressive strength of sandcrete blocks. Rice husk was collected from Hillcrest Agro-Allied Limited, Irepodun Local Government Area, Kwara State, and processed into ash of two particle sizes: 150 µm and 300 µm. Cement was replaced with RHA at 10%, 20%, 30%, and 40% by weight. The blocks were produced using a vibrated moulding machine and cured manually for 7, 28, and 56 days. Laboratory tests conducted included density and compressive strength tests. The results showed that as the percentage of RHA increased, the density and strength of the blocks decreased slightly compared to the control, though the reduction was more pronounced at higher replacement levels. The blocks containing 10–20% RHA performed best, showing comparable strength and density to the control samples, especially for the finer (150 µm) RHA. The findings indicate that properly processed RHA can serve as a suitable partial replacement for cement up to 20% without significantly affecting the structural quality of sandcrete blocks. This can help reduce cement consumption and promote the use of agricultural waste for sustainable construction.