Measurement of air permeability of geosynthetic clay liners

Abstract

Hydraulic barrier layer is the major component in the cover system of a modern landfill. The primary function of the barrier is to limit the amount of water infiltration. Another important function is to minimize the emission of landfill gas. In recent years, geosynthetic clay liners (GCLs) have been used in landfill covers as hydraulic barrier layer. However, in hot and arid areas the bentonite in GCLs may develop desiccation cracks. Before the cracks are closed upon wetting, significant amount of landfill gas might have already emitted into the atmosphere. To address this issue, air permeability tests were performed to assess the effectiveness of GCLs as a gas barrier. The results show that air can hardly pass through hydrated GCL specimens. However, the drying of GCLs induced significant increase of their air permeability. (C) 2000 Elsevier Science Ltd. All rights reserved.