Millet Husk Ash as Partial Replacement of Cement in Sandcrete Block

Abstract

This research is aimed at determining the suitability of millet hush ash (MHA) as partial replacement of cement in the production of sandcrete blocks. This study examined the physical and chemical properties of locally sourced millet husk ash as a pozzolana. Mix ratio 1:6 (cement: sand) was used in this study for sandcrete block production. Cement was partially replaced with MHA in varying percentages of 0, 10, 20, 30 and 40% by weight. The blocks were molded and cured for 7, 14 and 28 days. The compressive strengths of the blocks were determined at 7, 14 and 28 days by crushing using compressive strength testing machine. The result of the chemical analysis of the locally sourced millet husk ash showed that it is pozzolanic. At 28 days, the compressive strength of mixes with 0, 10, 20, 30 and 40% replacements of cement with MHA were 4.50, 4.00, 3.15, 2.00, and 1.15N/mm² respectively. Sandcrete blocks made with 10 and 20% replacements of cement with MHA met the minimum requirements for sandcrete blocks. The water absorption of Millet husk ash sandcrete blocks were found to be within the acceptable limits. This study recommends partial replacement of cement with 20% millet husk ash in sandcrete block production.