Evaluating the Hydration and Hydraulic Performance of a Geosynthetic Clay Liner (GCL) in Terms of Bentonite Mass per Unit Area

The hydration performance of GCL can be influenced from several factors one of which is bentonite mass per unit area (MPUA). This study reports the hydration and hydraulic conductivity of a GCL over a wide range of MPUA. GCLs were hydrated over a compacted silty sand for 7 and 30 days and water contents were determined. It was found that water content linearly decreased from 74 to 61% as the MPUA increased. Subsequent to hydration, GCLs were cut in 100 mm in diameter to determine the hydraulic conductivity. To reexamine the bentonite MPUAs in 100 mm diameter GCLs, the water-holding capacity of geotextile components was determined. It was found that water content of non-woven geotextiles increased from 12 to 45%, while that of woven geotextile remained constant at 2% when the bentonite MPUA increased. Finally, hydraulic conductivity tests were carried out on the samples with varying MPUAs. The results showed that the hydraulic conductivity of GCL ranged between 5.2 x 10(-12) and 2.6 x 10(-11) m/s. The hydraulic conductivity was still low (i.e., 9.2 x 10(-12) m/s) when the bentonite MPUA was decreased further to 1.8 kg/m(2)