A SYSTEMATIC REVIEW OF RICE STRAW ASH AND PULVERISED PALM KERNEL SHELL IN LATERITIC SOIL STABILISATION

Abstract

In tropical countries, agricultural residues present both waste-disposal challenges and opportunities for sustainable geotechnical applications. Lateritic soil, which is widely adopted for road construction, often have low strength and high plasticity and are thus in need of stabilisation. Rice Straw Ash (RSA) and Pulversihed Palm Kernel Shell (PPKS) are agricultural by-product-based materials. This study reviewed PPKS-stabilised lateritic soil with inference toward RSA's likely pozzolanic contribution. The synthesised evidence shows that the major contribution of RSA is physical reinforcement of the soil by pozzolanic reactions, resulting in improved strength characteristics, especially after curing and the contribution of PPKS is through physical reinforcement, resulting in the decreased Maximum Dry Density (MDD) and increased Optimum Moisture Content (OMC). The PPKS may contribute primarily through granular reinforcement and increased interparticle friction, whereas RSA may contribute through pozzolanic reactions and cementitious bonding. However, the amount of improvement, is very sensitive to the additive proportions, soil type and curing conditions. The results of this review support the potential of these two stabilisers as complementary stabilisers for low load applications but require further research with standardised testing protocols, testing at field scale under variable climates and evaluating life-cycle environmental impacts to build confidence in the design criteria.