Hydraulic conductivity of geosynthetic clay liner containing polymerized bentonite with low mass per unit area

The hydraulic performance of geosynthetic clay liners (GCLs) has been of interest since the 1990s. Conventional GCLs are made up of sodium bentonite. During the last decade, polymerized bentonite has been started to be used in GCLs to improve the barrier performance of GCLs against aggressive leachates. In this study, a GCL roll which had been used in a landfill liner was supplied from the construction site. The bentonite of the GCL was polymerized (P-GCL). The mass per unit area (MPUA) of the GCL was within the range of 3.2-4.0 kg/m 2 , which was low compared to GCLs reported in the literature. The aim of this study is to investigate the hydraulic performance of P-GCL to deionized water (DIW) and trona ash leachate (TAL) as a function of mass per unit area. The hydraulic conductivity of P-GCL to deionized water was high at the beginning of the tests (10 -7 m/s). However, the hydraulic conductivity gradually decreased to 2.0×10 -11 m/s. Then, hydraulic conductivity tests were conducted on non-prehydrated and prehydrated P-GCLs using trona ash leachate. Even though GCLs were prehydrated with deionized water, the hydraulic conductivity was above the allowable limit suggested for the barriers (1.0×10 -9 m/s), indicating the role of mass per unit area on the hydraulic conductivity.