Improving hydraulic performance and durability of sandwich clay liner using super

The hydraulic performance and durability of geosynthetic clay liner containing various amounts of sodium polyacrylate polymer are experimentally studied. Sodium polyacrylate, generally known as a super-absorbent polymer, is a polymeric material with a potential of high water absorbance due to its chemical structure. In this study, sodium polyacrylate powder is used as a partial replacement of bentonite as much as 3%, 5% and 7% by the weight of bentonite. For comparison, the hydraulic performance of geosynthetic clay liner without super-absorbent polymer is also experimented. Atterberg limits, free swell index, hydraulic conductivity, self-healing capacity and wet/dry cycle tests are conducted in order to assess how super-absorbent polymer can affect the performance of geosynthetic clay liners as landfill liners and covers. The results show that the hydraulic conductivity and self-healing capacity of geosynthetic clay liner are relatively enhanced by super-absorbent polymer inclusion. The results of wet/dry cycle test show that using super-absorbent polymer as a partial replacement of bentonite considerably improves the durability of geosynthetic clay liner against wet/dry cycles. Geosynthetic clay liner containing super-absorbent polymer shows a negligible increase in hydraulic conductivity while there is a noticeable increase in hydraulic conductivity of specimen without super-absorbent polymer after 10 cycles of wetting and drying