Comparative Assessment of the Stabilization of Lime-Stabilized Lateritic Soil as Subbase Material Using Coconut Shell Ash and Coconut Husk Ash

The effect of two agro-based admixtures—coconut shell ash (CSA) and coconut husk ash (CHA)—on lime-stabilized lateritic soil were assessed and their results were compared with respect to the most potent stabilizer that can be used for the stabilization of lateritic soil as sub-base material in this study. Engineering properties such as California bearing ratio (CBR) and unconfined compressive strength (UCS) were determined for both stabilizers. The peak values of the CBR and UCS for the CSA were obtained when the soil was treated with a combination of 4% CSA + 4% lime content while that of the CHA were observed at a combination of 16% CHA + 4% lime content. However, the CBR and UCS values for the CSA were found to be higher than that of the CHA treated soil. The UCS and CBR for the soil specimens treated separately with CSA and CHA did not meet the criteria necessary to be qualified as sub-base material but they adequately satisfy the requirement as subgrade material.