ENGINEERING PROPERTIES OF CONTAMINATED COMPACTED CLAY LINERS

Abstract

Compacted clay liners are widely used as liners in the engineering landfills because of their low hydraulic conductivity, high contaminant attenuation and cost effectiveness. To construct clay liners, processed and natural clays are widely used to create impermeable liners in solid waste disposal landfills. The engineering properties of clay liners can be significantly affected by the leachate from the waste mass. In this study, the effect of different inorganic salt solutions will be experimentally investigated. Different inorganic salt solution will be used at different concentrations. Two type of inorganic salt MnSO4 and FECL3 are used at different concentration 2%,5%, 10%. Clay used in this study was the CL- clay (kaolinite ) .The test will be conducted after permeation of salt solutions will be completed. The result show that the liquid limit, plastic limit and plasticity index increased as the salt concentration increased. Also, the unconfined compressive strength increased as the concentration of salts increased. While the permeability tend to decrease as salt concentration increased. The finding of this study indicated that the salt in pore fluid reduce the compression index as the concentration increased from 2% to 5% , after that the Cc nearly constant. The swelling index tend to increase slightly as the concentration of MnSO4 increased, while its decrease as the concentration of FeCL3 increased. The study proved that the CL- clay (kaolinite ) can be used as liner material for the construction of the MSW landfill site. Furthermore, according to these results, the CL-clay suitable for using as a compacted clay liner to be used in construction of landfill in Baghdad city.