| Summary: | This study aims to examine the performance of fly ash mixed materials with bentonite binder (FAB) as a recent low-cost containment system to withstand leachate infiltration. The mixture of fly ash with clay (bentonite) may potentially utilized as semi-permeable liner with low permeability and promising stability. Direct shear, permeability testing, Atterberg limit and specific gravity test have been conducted as a preliminary study to determine the precise mixture composition of fly ash-bentonite (FAB) intended for landfill liners. Some mixtures that consist of fly ash with the following bentonite addition: 0% (FAB0), 15% (FAB15), 20% (FAB20), and 25% (FAB25) generate internal friction angle of 42º, 39º, 20º and 19º respectively. The results indicate that the more addition of bentonite into fly ash will reduce shear stress of the mixture while lowering the permeability value. In addition, fly ash containing 25% of bentonite that cured with saline solution (FAB25c) was tested to investigate the effect of salt into fly ash-bentonite mixture. Curing with saline solution tends to reduce shear strength of the FAB mixture. The slope simulation presents that the addition of bentonite will increase bonding between particles, bearing capacity, and shear strength of the material. The largest safety factor of 1.674 obtained from FAB20 material meets the safety standard for short-term slope stability. Fly ash containing 25% of bentonite is expected to be an alternative landfill liner material.
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