INFLUENCE OF BRITISH STANDARD LIGHT COMPACTIVE ENERGY ON RICE STRAW ASH AND MILLED PALM KERNEL SHELL STABILISED LATERITIC SOIL

Abstract

Lateritic soil commonly adopted in road construction often contain high clay content, high plasticity and inadequate strength, limiting it direct use in pavement layers. This study investigates the performance of lateritic soil stabilised with Rice Straw Ash (RSA) and Milled Palm Kernel Shell (MPKS) using British Standard Light (BSL) compactive energy. Lateritic soil was stabilised with RSA and MPKS independently at a proportion of 0 –15% at 2.5% intervals by weight of the soil. An optimum 7.5% RSA content was combined with varying MPKS contents. Compaction and California Bearing Ratio (CBR) were evaluated. The compaction result was 1620 kg/m³ for unstabilised soil and 1530 – 1609 kg/m³ for RSA stabilised soil, respectively. The corresponding values were 1420 – 1600 kg/m³ for MPKS stabilised soil and 1411 – 1583 kg/m³ for combined RSA-MPKS stabilised soil, respectively. The CBR increased with increase in proportion of the agricultural residues with 7.5% RSA + 5% MPKS blend outperforming the individual residues. The findings established that the combined application of 7.5% RSA and 5% MPKS provided a viable approach for improving lateritic soil. Thus, lateritic soil stabilisation with the combined additives is more suitable for soil performance enhancement in road construction. However, further research should be carried out using higher compactive energies.