Suitability of Kaolinite Flyash Mixture as a Liner Material

Use of sanitary landfills for waste containment is one of the oldest and most pop-ular waste disposal technique. The landfill liner is designed to isolate the waste from the soil beneath to minimize the passage of leachate into the Groundwater. . Usually compacted liner materials consist of soil rich in clay minerals for their low hydraulic conductivity. This study is an attempt to assess the use of a waste material, fly ash( as a potential liner material by mixing it with kaolinite in various percentages ranging from 2-20%. fly ash is non-plastic and possess very low shrinkage. With the addition of kaolinite in the mixture, the plasticity is expected to increase and the fly ash is expected to reduce the swelling and shrinkage, pre-venting formation of any cracks. Due to its swelling properties, kaolinite in the mixture is expected to act as a self-sealing, low permeability hydraulic barrier. To determine the viability of fly ash- kaolinite mixture as a liner material, the mixture was compacted at its optimum moisture content and maximum dry density and laboratory tests were conducted to obtain the various geotechnical parameters such as plasticity, shrinkage, permeability, free swell index, c, and unconfined compressive strength. It was found that a compacted mixture of kaolinite with fly ash with the percent of kaolinite in the mixture between 12-20% had the required hydraulic conductivity and strength properties to be used as a liner material.