Strength Development in Lateritic Soil Stabilised with Coconut Shell Ash for Highway Pavement Construction

Abstract

Lateritic soil has found wide usage in highway pavement construction in the tropics, however, there are instances that they are unsuitable because of their properties, hence the need for improvement through stabilisation. This research focussed on the utilisation of coconut shell ash for stabilising of lateritic soil for highway pavement construction. The lateritic soil was treated with 3 to 12% coconut shell ash (CSA) to assess its effect as a soil stabilising admixture on the geotechnical properties of the lateritic soil while the soil with 0% CSA is the control. The percentage passing sieve no. 200, liquid limit and plasticity index reduced with increase in the CSA content, this indicates that the susceptibility of the soil for water has been reduced. However, the maximum dry densities of the treated soil increased with increasing content of CSA but the strength index, California bearing ratio (CBR) decreased. Coconut shell ash though is a good pozzolan cannot therefore be used as a stand-alone stabilizer for treating lateritic soil however, the stabilized soil could be used as a subgrade foundation material in road pavement construction.

Keywords: Coconut shell ash, Lateritic soil, Stabilization, Highway Pavement, Compaction, California bearing ratio