ABSTRACT
This chapter presents brief descriptions of the three types of materials commonly used for landfill liners and the factors which may affect the permeability of the liner. These materials are compacted clay, amended soils, and geosynthetics. The chemical stability of soil liners can be improved through processes that make the soil more dense or create cementation between soil particles. This stabilization can be done using additives or through mechanical processes. The presence of macrofabric defects in barrier liners can be controlled and limited with good construction techniques. During construction, the following factors should be controlled to limit the amount of defects present in the liner and to assure its integrity and ‘impermeability’: compaction or placement of the liner, desiccation or freeze/thaw degradation, liner thickness, and chemical composition of the liner. The permeability of a piece of geosynthetic can be tested for with ASTM E96 and using the leachate instead of water.
