The Use of Rice Husk Ash as Partial Replacement for Cement in Concrete
The study examines the use of rice husk ash as partial replacement for cement in concrete by determining various properties of rice husk ash through laboratory experiments. The objective of the study includes, determining the specific gravity of RHA, the effect of RHA on compressive strength of concrete and on properties of concrete such as density and workability. The results of the study revealed specific gravity of 2.36 for the RHA used. The use of RHA in the mix caused a significant decrease in the study compared with concrete produced with only OPC. The water absorbing quality of RHA is a major physical property which affects the workability of OPC/RHA concrete. Compressive strength tests carried out on OPC/RHA concrete at varying ages to 28 days and at varying water cement ratios appear to indicate that the material is adequate for concrete making. In addition, OPC/RHA concrete gain strength faster as a result of reduction in porosity caused by RHA. At 28 days, specimens with 0.6 water cement ratios gave strength greater than 20N/mm2 (min) required for structural purposes as recommended by CP 110. Rice husk is a loose raw material for construction industry which is produced daily as waste and it can be obtained at a much lower cost than the cement which it replaces. Also, its usage should minimize the disposal problems faced by the producing companies and enhance environmental protection.