Rice Husk Ash Cement - An Alternative Pozzolana Cement For Kenyan Building Industry.

Abstract

A survey was carried out to assess the quantities of rice husks at the rice milling plants in the country. Mwea, Ahero, West Kano and Bunyala rice growing areas were visited. Large deposits of husks exist at rice milling plants in these areas with Mwea leading. Samples of rice husks from Mwea Rice Mills were used to confirm the pozzolanic properties of rice husk ash (RHA). Chemical analysis of the ash showed high silica (SiO2) content (more than 50%) which is a requirement for a good pozzolanic material. The engineering properties of the cement resulting from a mixture of OPC plus RHA and lime plus RHA were satisfactory with addition of up to 50% RHA. The RHA improved greatly the compressive strength of lime. The cost of producing RHA was considered in pricing the resulting binder and it showed that the use of RHA to supplement OPC and lime reduced the overall cost of the binder.