Geosynthetic clay liners: effect of structural properties and additives on hydraulic performance and durability

In this study, the effects of some structural parameters and also two kinds of additives on hydraulic performance, self-healing ability and wet/dry durability of GCL are experimentally studied. Structural parameters include bentonite mass per unit area of GCL and needle-punching density. Nano-clay particles and sodium poly-acrylate which is a kind of superabsorbent polymers (SAPs) are used as additives. The results show that bentonite mass can affect the permeability of GCL, but it does not impress the healing time and wet/dry durability. Needle-punching density in needle-punched GCLs positively affects both hydraulic performance in case of hydraulic conductivity, self-healing capacity and wet/dry durability. The test results also show that nano-clay particles considerably improve the permeability and self-healing capacity, while they have negative effects on durability of GCL. On the other hand, the wet/dry durability of GCL dramatically enhances by using SAP, while hydraulic performance of GCL is not much affected by SAP inclusion. Experimental results show that using both nano-clay and SAP in GCL can improve its permeability, self-healing capacity and wet/dry durability simultaneously.