GCL grade bentonite enables self-repair due to its swelling properties and acts effectively as a barrier material for liners. It also exhibits strong sealing properties and minimizes leakages. CMS Bentonite which has more than 70% of montmorillonite, is considered better and used popularly in GCLs. It acts as a carpet by obstructing waste and liquid containment. The ability of GCL to retain seepage inside of the landfill is dependent on hydraulic conductivity.

