Experimental Investigation on Rice Husk Ash Blended Concrete Performance in Terms of Compressive Strength

Abstract : Concrete is the most widely used construction material globally, but its production relies heavily on Portland cement, contributing to significant CO₂ emissions and creating a substantial environmental burden. Rice husk ash (RHA), an abundant agricultural by-product with high silica content and pozzolanic potential, presents a promising opportunity for partial cement replacement, offering environmental and economic benefits. This study investigates the partial replacement of cement with RHA in concrete mixes, evaluating its effect on compressive strength. Concrete specimens were prepared with 0%, 5%, 10%, 15%, and 20% RHA replacement levels by weight, and compressive strength tests were conducted at 7 and 28 days. The gradual decrease in compressive strength with increasing RHA content is evident in the data. For the 28-day strength, the control mix registered 22.73 MPa, while the 5% RHA mix had 19.30 MPa, and the 20% RHA mix reported 13.92 MPa. Strength performance is optimal with a 5% replacement level, which is the closest to the control. This suggests the partial replacement of cement with RHA up to 5% is reasonably attainable, especially considering the marked reduction in cement content, which translates to a reduction in CO2 emissions, the recycling of agricultural waste, and the primary mechanical performance.