Geosynthetic clay liner Concrete protection mat (GCL)
 -geosynthetic clay liners ,lake mat ,GCL waterproof material
Geosynthetic clay liner (GCL) is a high performance needle punched environmental reinforced composites which combine two durable geotextile outer layers with a uniform core of natural sodium bentonite clay to form a hydraulic barrier. 
Fibers from the non-woven geotextile are needle punched through the layer of bentonite and incorporated into the other geotextile (either a woven or non-woven). When hydrated under a confining load, the bentonite swells to form a low permeability clay layer with the equivalent hydraulic protection of several feet of compacted clay.
It is used to prevent water leakages in areas of artificial lakes, waste disposal fields, underground garage, top building gardens, reservoirs, oil warehouses, and chemicals accumulating fields.