Geotextile waterproofing mats are specialized geomembranes used for artificial lakes, landfill sites, underground parking garages, rooftop gardens, ponds, oil storage facilities, and chemical storage yards to prevent leakage. They are made by filling high-expansion sodium bentonite between a custom composite geotextile and nonwoven fabric, and the needle-punched bentonite geomembrane forms numerous small fiber spaces that prevent bentonite particles from flowing in one direction. When in contact with water, these spaces create a uniform, high-density gel-like waterproof layer within the mat, effectively preventing water leakage.

Geosynthetic clay lining can be categorized by production process into: needle-punched sodium bentonite waterproof geotextile, needle-punched film-coated sodium bentonite waterproof geotextile, and adhesive sodium bentonite waterproof geotextile. The needle-punched film-coated sodium bentonite waterproof geotextile involves applying a layer of high-density polyethylene geotextile to the nonwoven geotextile surface of the needle-punched sodium bentonite waterproof geotextile. The adhesive sodium bentonite waterproof geotextile is a sodium bentonite produced by bonding the bentonite particles to a high-density polyethylene board using an adhesive, and then compressing it.

The mineralogical name for bentonite is montmorillonite. Natural bentonite is primarily divided into two main categories based on chemical composition: sodium-based and calcium-based. Bentonite has the property of expanding when wet. Generally, calcium-based bentonite expands to about three times its original volume, whereas sodium-based bentonite absorbs five times its own weight in water, expanding to 15-17 times its original volume. Locking sodium-based bentonite between two layers of geosynthetic materials serves to protect and reinforce, giving the GCL a certain overall shear strength.