Effect of Rice Husk Ash on The Strength Characterıstıcs of Cement Blocks

Rice husk ash (RHA) is a promising pozzolanic alternative material for partial replacement of ordinary Portland cement to increase the durability and strength of concrete. This study examines the use of Rice Husk Ash (RHA) as a partial replacement for Ordinary Portland Cement (OPC) in the production of hollow cement blocks. The aim is to evaluate the impact of RHA on the compressive strength, workability, and water absorption properties of the blocks. RHA was introduced as a replacement for OPC at levels of 0%, 25%, and 50%, and tests were conducted after 7 and 14 days of curing. The results indicate that increasing RHA content leads to a reduction in compressive strength, with the 50% RHA mix exhibiting the lowest strength. This is attributed to the porous nature of RHA, which weakens the cementitious matrix. However, workability improved as RHA content increased, due to its water-reducing properties. The water absorption of the blocks also increased with higher RHA content, corresponding to the increased porosity. Despite the strength reduction, the pozzolanic activity of RHA suggests potential for long-term strength gains. The findings demonstrate that RHA can be a viable alternative for cement in non-structural applications, contributing to sustainable building practices by utilizing agricultural waste and reducing the reliance on cement. This research supports the integration of RHA into the construction industry as an eco-friendly material, promoting both waste management and carbon footprint reduction.