Geotechnical behaviour of lateritic soil reinforced with brown waste and synthetic fibre

Abstract

An experimental programme was undertaken to study the effect of individual and combined inclusion of locally available brown waste materials (areca nut husk, water hyacinth stem) and commercial synthetic fibre (recron 3s) on the geotechnical characteristics of a lateritic soil. Two models of fibre reinforcement on soil were considered: firstly, the fibres were mixed randomly with the soil and secondly, the fibres were introduced sequentially in horizontal discrete layers in the direction of the major principal plane of the soil matrix. A series of laboratory tests including the compaction test, unconfined compressive strength and California bearing ratio were carried out on soil reinforced with areca nut coir, water hyacinth stem and recron fibre at systematically varying percentages of them to examine their influence on the strength of reinforced soil. The results of this investigation provide insights to quantify natural fibre reinforcement technique compared to synthetic fibres in both the random and planar inclusion methodology. Samples reinforced with recron and coir, individually and in combination showed increasing strength with increase fibre content in both the models, while water hyacinth stem showed an initial increase followed by a decline at higher fibre content. The optimum fibre content of 0.5% for areca nut coir, 0.5% for recron and 0.125% for water hyacinth stem by dry weight of soil were recommended for strengthening the lateritic soil.