Bentonite and Geosynthetic Clay Liners (GCLs)
A geosynthetic clay liner (GCL) is comprised of two geotextiles that are needlepunched together, encapsulating a layer of sodium bentonite clay or polymer-enhanced clay between them. GCLs are known for having consistent, very low permeability. They have the unique ability to seal around penetrations, self-heal punctures, and self-seam at the overlaps.
GCLs are widely used for water containment applications (ponds, reservoirs, channels, etc). In these instances, the Bentomat CL series of GCL are used (scroll below).
For waste containment applications, depending on the chemistry of the material in contact with the GCL, a standard bentonite-based GCL or a polymer-modified GCL will be selected. Additionally, site conditions will dictate the interface and internal shear strength requirements. CETCO BENTOMAT and Resistex GCLs are available in a variety of geoxtextile configurations to meet site-specific shear strength requirements.
Contact us to support with selecting the appropriate GCL for your project. We have a database of previous compatibility and shear strength testing. Additionally, we can coordinate site-specific compatibility and shear testing for your project.
In some cases, site soils may not be conducive to containing water on their own. When the soil is borderline, blending bentonite might be a cost-effective approach to hauling low-permeability clay or a synthetic lining material.
Bulk bentonite is available in granular or powdered variations. Typical applications for bulk bentonite include blending with site soils to decrease the hydraulic conductivity, in ISS applications, or slurry walls.
Sodium bentonite-based GCLs provide an excellent hydraulic barrier in applications where the leachate is relatively non-aggressive, or in composite lining applications where the GCL is overlain by a thermally welded geomembrane.
CETCO RESISTEX GCLs are polymer-modified bentonite GCLs that are engineered to provide the highest level of chemical compatibility for hydraulic barrier performance in extremely aggressive leachate environments. We recommend project-specific compatibility testing for the proper selection from the RESISTEX family of GCLs.