An Investigation on the Influence of Palm Oil Fuel Ash (POFA) and Magnesium Chloride (MgCl2) on Improving the Strength Characteristics of Expansive Soil as Sub-Grade for Flexible Pavements

Abstract

Expansive soils create serious trouble in construction works, especially in pavements, because the soil subgrade beneath the pavement is prone to moisture which causes swelling when they are wet and shrink during dry periods. This swell and shrink phenomenon leads to cracks, settlement and early damage in pavements. The Expansive soils are spread widely across many regions of the world especially in Indian sub-continental areas like Indo-Gangetic plains, Coastal areas of the Indian peninsula and across the Deltas of the Indian rivers. The Expansive soils remain a major issue in developing countries such as India, where constructions are frequent and the scarcity of spaces in the densely packed cities create a situation where there would be a necessity to reclaim the spaces that sits on expansive soils for which the soil stabilization is essential. POFA is a pozzolanic industrial byproduct generated from the edible oil industry, and its utilization in construction activities provides an efficient and environmentally friendly solution.  In this research, an attempt was made to amend the strength of ES, by incorporating POFA as an admixture along with Magnesium Chloride as a chemical additive. Various laboratory tests were conducted to evaluate the changes in the geomechanical properties of the ES. The results showed a vivid increment in the strength and load-carrying capacity. The findings proved that POFA and MgCl₂ are economical and eco-friendly materials for stabilizing expansive soils as sub-grade to improve the performance of  flexible pavements.