Experimental Investigation of Red Soil Blended With Bentonite and Lime as a Landfill Liner

Abstract

To control the migration of contaminants generated from the leachate, the liners are used in landfills. Compacted clay liners are widely used as liner materials due to the low value of hydraulic conductivity and large attenuation capacity. In the present work, an experimental study on red soil which is locally available is amended with bentonite use as a liner material for efficient leachate containment in landfills. The primary objective of this work is to determine the geotechnical properties of red soil blended with bentonite as a material for liners. The clay liners performance primarily depends on hydraulic conductivity. The hydraulic conductivity of the red soil is higher than the recommended limit (i.e.>10^-7cm/s). Commercially available bentonite was blended with red soil to decrease the hydraulic conductivity. The permeability tests and falling head tests were conducted on 5%, 10%, 15%, and 20% bentonite by weight blended with red soil to evaluate hydraulic conductivity. From the experimental studies, it is clear that the red soil blended with 15% bentonite has a hydraulic conductivity value less than the requirements of landfill clay liner(i.e.<10^-7cm/s). However, the Compressive Strength (CS) of blended red soil with 15% bentonite was less than 200 kPa, which is less than the minimum CS required for liner material. Lime was added to enhance the CS of the soil mixture and further studies were carried out. Swelling behavior is the major problem that is to be addressed during and after the construction of landfills. This study also presents the swelling behavior of red soil blended with bentonite and other additives.