Abstract

Traditional methods of soil stabilization have limitations, prompting the search for sustainable alternatives, particularly in waste materials. Groundnut shell ash (GSA) and rice husk ash (RHA) were used to stabilise laterite soil due to their high silica content. Different mix ratios of GSA and RHA were subjected to standard compaction tests, California bearing ratio tests and unconfined compressive strength tests. Generally, the results showed improved soil mechanical properties by adding GSA and RHA. The California Bearing Ratio (CBR) of the laterite soil increases following the addition of RHA and GSA. A mixture composed of 90% soil and 10% GSA demonstrates the least incremental increase at 62.07%, ultimately resulting in a CBR of 5.17%, while a combination of 75% soil, 15% RHA, and 10% GSA exhibited the most substantial rise, boasting an impressive 196.24% increase and achieving a CBR of 9.45%. The unconfined compressive test gave an unconfined compressive strength (UCS) and cohesion of 48.95 Kpa and 24.475 Kpa respectively for untreated laterite soil. These values were increased to 76.96 Kpa and 38.48 Kpa for UCS and cohesion of a treated soil consisting of 90% soil and 10% GSA. The mixture comprising 75% soil, 15% RHA, and 10% GSA demonstrates the most significant rise, boasting an impressive 286.31% increase in UCS values and culminating in a UCS of 189.1 Kpa and cohesion of 94.55 Kpa.