Soil Water Characteristic Curve Parameters of Compacted Lateritic Soil Treated with Bagasse Ash

Abstract

Lateritic soil treated with up to 12% bagasse ash by dry weight of soil was prepared at –2, 0 and +2% of the optimum moisture content (OMC) and compacted with standard Proctor energy, for use as a suitable material in waste containment application. The treated soil was assessed to determine its soil water characteristic curve (SWCC) parameters that were used to predict the measured laboratory SWCC with Brooks - Corey (BC) and Van Genuchten (VG) models. VG n fitting parameter increased to a peak at OMC and thereafter decreased with higher molding water content, while α fitting parameter generally increased with higher molding water content. BC pore size distribution index (λ) increased with higher molding water content, while no clear trend was observed for air entry suction (Ψa) with higher molding water content. VG n increased, while α decreased with higher bagasse ash content. Higher BC Ψa and λ were obtained with higher bagasse ash content. BC model tends to over predict the volumetric water content (θ), particularly at low matric suction values, while VG model under predicts θ. Generally, the measured and predicted SWCC did not show great variation from each other but are fairly close.