The effect of partial replacement of Nigerian Portland limestone cement with rice husk ash agricultural waste in concrete

Rice Husk is an agricultural waste which when burnt under controlled temperature, produces an ash Rice Husk Ash (RHA) owing to its rich content in silica, which is used as a super-pozzolanic material for the partial replacement of Cement in concrete. Presently, large amounts of RHA are generated in both Rural and Small-Scale Industries which has a high impact on the environment. In this work, Portland limestone cement (PLC) was partially replaced at 0%, 5%, 10%, 15%, 20%, 25% and 30% with RHA. A control of 0% PLC replacement was adopted. Compressive strength was investigated A mix ratio of 1: 1.12 : 3.07 with water-cement ratio of 0.5 was adopted for a curing period of 7, 14, 28, 60 & 90 days. The result showed that the compressive strength decreased as the percentage of RHA increased. At 90 days, compressive strength of 34.12, 29.70, 28.30, 26.67, 24.48, 23.96 and 23.42N/mm 2 was recorded for 0, 5, 10, 15, 20, 25 and 30% replacement level respectively. It was recommended that further work should be investigated to check for the suitability of partial replacement of other grades of Nigerian cement with RHA in concrete.