An investigation into strength and permittivity of compacted sand-clay mixtures by partial replacement of water with lignosulfonate

Abstract

Strength and permeability of sand-bentonite mixtures are of main concern, particularly in liner design. This study presents the results obtained from an experimental investigation of strength and permittivity of compacted sand-bentonite mixtures in the presence of water-reducing admixture of lignosulfonate. For this, sand-bentonite mixtures containing 4, 8, 12, 16% of bentonite were subjected to standard Proctor tests, to obtain the optimum water content and maximum void ratio of the mixtures. Similar specimens were prepared by partially replacing 0.5, 1 and 2% of water in the mixture with lignosulfonate. Additional specimens containing 16% of bentonite were prepared with 5% deviation towards the wet and dry sides of optimum water content, which was partially replaced with lignosulfonate for evaluation of the effects of deviation from optimum moisture content during densification. It was observed that partial replacement of water with lignosulfonate slightly increases the strength and decreases the permittivity, and that this effect was more pronounced as the replacement level was increased. Additionally, test results reveal that lignosulfonate replacement was more effective on the dry side of optimum water content.