Influence of Rice Husk Ash on the Engineering Properties of Soil

Abstract

The study investigated the effects of rice husk ash (RHA) on the engineering characteristics of soil. The RHA, which was obtained from the combustion of rice husks, an agricultural waste was introduced to stabilize natural soil samples. Laboratory tests such as sieve analysis, compaction, specific gravity, California bearing ratio (CBR) and Atterberg limit tests were conducted on the natural soil samples and soil samples stabilized with 2%, 4%, 6%, 8% and 10% RHA content. The original soil samples were classified as A-1-b (G.I. = 0). The results from the various laboratory tests showed a slight decrease in optimum moisture content (OMC) and an increase in maximum dry density (MDD) of the soil samples between 0% to 2% RHA content and an increase in OMC and decrease in MDD from 2% to 10% RHA content. The results also showed an increase in the CBR of the samples as the ash content increased. For the soil to be used as sub-base material, stabilization with a minimum of 10% RHA and 2% RHA is required for soil sample A and soil sample B respectively. Thus, RHA is recommended for use in the stabilization of natural soils to enhance its performance as pavement material.