The Effect of Different Mixtures on Desiccation Crack Behaviour and Hydraulic Stability of a Compacted Liner

Abstract

Landfills utilize leachate containment systems featuring a compacted liner layer with low hydraulic conductivity. Typically, the required hydraulic conductivity is ≤ 1 × 10⁻⁵ cm.s-1 for final cover liners and ≤ 1 × 10⁻⁶ cm/s for bottom liners, to prevent leachate from migrating into surrounding soil and groundwater. This study tested composites made from textileindustry sludge amended with bentonite, lime, and rice husk ash to assess their potential as landfill liner materials. Results indicated that composites with 40% or more bentonite (by mass) mixed with dewatered sludge could meet permeability standards. The addition of 1% lime and 8% rice husk ash further reduced permeability. Incorporating bentonite increased cohesion and lowered the internal friction angle, while lime and rice husk ash raised the internal friction angle and caused fluctuations in cohesion.