Reevaluation and Modification of Plasticity-Based Criterion for Assessing the Suitability of Material as Compacted Landfill Liners

Abstract

Compacted landfill liner is an integral part of a waste management system, which minimizes the migration of harmful contaminants to geoenvironment and groundwater. Low hydraulic conductivity is the most important requirement for geomaterial used as compacted landfill liners. Because of this, high plastic geomaterials are preferred for such applications. Therefore, plasticity characteristics can be used as an initial guideline for assessing the suitability of materials used as a landfill liner. Such guidelines are important because of the fact that hydraulic conductivity determination is extremely time consuming for plastic geomaterials, and a quick assessment of material properies is always expected in the planning stage of the project. The existing methodology on the basis of plasticity criterion is not suitable for high-plastic soil, which otherwise is a very useful material for landfill liners. Considering this, the present study deals with the re-evaluation of plasticity-based criterion for assessing the suitability of medium and high-plastic geomaterials used as a compacted landfill liner. The development of the criterion is on the basis of the test results of bentonite–fly ash mix, which is used to represent a wide range of plasticity. The proposed criterion is further verified on the basis of the data reported in the literature. The present study also demonstrates the potential application of fly ash in combination with bentonite for landfill liner construction.