Hydration behavior of geosynthetic clay liner with polymerized bentonite

The hydration behavior of a GCL with polymerized bentonite (PB-GCL) was investigated by laboratory column tests in terms of hydration gravimetric water content (w), apparent degree of saturation (S-r*)and air permeability (k(air)), and compared with those of a GCL with natural bentonite as the core (NB-GCL). In cases of deionized water (DI water) and 0.1 M NaCl solution as pore water of the subsoil, the PB-GCL had higher final w values than the NB-GCL, but the values of S-r* are similar. The values of k(air) of the PB-GCL are approximately four orders lower than that of the NB-GCL. In addition, k(air) of the PB-GCL at S-r* = 40% is comparable with that of the NB-GCL at S-r* = 70%. In the case of the subsoil with 0.6 M NaCl solution, the final value of k air of the PB-GCL is about half of the NB-GCL. These results indicate that cation concentration in a subsoil has a considerable influence on the hydration behavior of a GCL. It is suggested that the PB-GCL has a better hydration performance than the NB-GCL.