Volume Change Behavior of Sand-bentonite Liner and the Effect of Cement Enhancement

Abstract

This paper presents the volume change behavior of compacted mixtures containing different amounts of sand and bentonite. The volume change behavior of two samples containing 15% and 10% bentonite are compared with samples containing 5% and 15% bentonite and 5% cement addition by dry weight. The effect of cement addition to optimum water content, maximum dry density, swell and compressibility behavior of sand-bentonite mixtures is studied. The test results show that addition of cement prevents the swelling of samples and significantly reduces the compressibility. The compressibility of sand-bentonite mixtures is also analyzed and the relationship between swell pressure and shape of the compression curve is discussed. The hydraulic conductivity of all samples tested are determined to be much lower than the minimum required for landfill barriers