Effect of bentonite on the saturated hydraulic conductivity of landfill liners based on dune sand

Sand-bentonite (SB) mixtures have been used successfully for construction of hydraulic barriers when clayey soils are not available. Compacted layers of SB mixtures have been proposed and used in a variety of geotechnical structures as engineered barriers for the enhancement of impervious landfill liners. In the practice we will try to get an economical mixture that satisfies the hydraulic and mechanical requirements.The effects of the bentonite additions are reflected in lower water permeability, and acceptable shear strength. In order to get an adequate dune sand bentonite mixtures, an investigation relative to the hydraulic and mechanical behavior is carried out in this study for different mixtures. According to the results obtained, the adequate percentage of bentonite should be between 12% and 15 %, which result in a hydraulic conductivity less than 10E–6 cm/s, and good shear strength.