Desiccation Effect on Compacted Tropical Clay Treated with Rice Husk Ash

Compacted clayey soils are used as hydraulic barriers in waste containment facilities such as liners and covers, in order to control infiltration into the waste and hence leachate from the waste to the ground water. Laboratory studies on compacted tropical clay treated with up to 16% Rice Husk Ash (RHA), was carried out using standard Proctor compactive effort; at water contents between 2% dry and 4% wet of optimum to access the suitability of the material as a land fill cover. Compacted samples, extruded from the compaction mould were allowed to air dry in the laboratory for a 30 day period to access the effect of desiccation shrinkage. Results show that changes in mass and volumetric shrinkage strain were large within the first five days of drying. Volumetric shrinkage strain increased with higher moulding water contents/water contents relative to optimum, higher RHA treatment. All specimens prepared at 2% dry of optimum and at optimum moisture content for up to 8% RHA treatment met the regulatory maximum allowable volumetric shrinkage strain value of 4%, showing the suitability of the material as a cover in municipal waste containment facility and beneficial reuse of the agro waste product.