ABSTRACT
This paper will touch mainly geosynthetic clay liners (GCLs) and the recent development of multi-component GCLs in landfill applications and show their benefits. GCLs are mostly needle-punched, fibre-reinforced composites that combine two durable outer layers and an intermediate uniform core of high-swelling powder sodium bentonite clay, which acts as the barrier component. These uniform needle-punched GCLs form a direction-independent shear strength transferring sealing barrier. When the bentonite core hydrates with fresh water, the bentonite swells and forms a low permeability gel layer, which outperforms traditional, thick compacted clay liners, due to the bentonite's ability to self-seal and re-heal. GCL improvements, since the invention of needle-punched GCLs in 1987 and contribution to the understanding and adoption of GCLs in engineering and construction, have been numerous. This paper will discuss the new GCL technology, the advantages of the polymer coating added to the GCL, the current test results, the applications where such GCL products are ideally used and the necessary design considerations.
