Used as an impermeable lining material and as a fluid or containment barrier. When hydrated it provides a better hydraulic performance than a metre of compacted clay. Differential settlement is accommodated by the high plasticity and self-sealing properties of sodium bentonite.Natural environmental stresses such as freeze/thaw and desiccation/rewetting cycles have no effect on the performance of Bentotex GCL.
Bentotex GCL is an extremely cost effective and robust solution which requires no additional materials (i.e. a protection fleece or geotextile) or specialist installation by qualified welding contractors it becomes a practical and economic alternative to a traditional man made liner or a compacted clay layer.
- CE marked.
- Excellent climatic resistance.
- Excellent slope stability characteristics.
- Fast and easy to install.
- High chemical resistance.
- Highly competitive installed cost.
- Lowest flux of all available GCLs.
- Resistance to differential settlement.
- Self-sealing if punctured.
- Landfill lining and capping.
- Liquid containment.
- Mining applications.
- Quarry settlement and dewatering points.
- Spill or secondary containment.
- Water course liners.
Also designed to prevent water and gas ingress in below-ground structures.
Standard product features
- Material: Polypropylene geotextile. Bentonite core.
- Thickness: 6 mm.
- Colour: Grey.
- Roll size (w x l): 5 x 40 m.
- Roll weight (kg): 1220
- Bentonite swell index (to ASTM D5890): 27 ml/2g (minimum).
- Static puncture resistance (to BS EN ISO 102236): 1800 N.
- Tensile strength (to BS EN ISO 10319): 10 kN/m.
Geosynthetic clay liners (GCLs) are an established sealing product in the civil engineering and groundworks industry. They are used in landfill caps and base liner applications under roads, railways, secondary containment for above ground tank farms, as well as within various other containment structures such as dams, canals, ponds, rivers and lakes. They are also used for waterproofing of buildings and other similar structures.
Rolled out like a carpet to provide a durable impermeable liner, geosynthetic clay liners consist of a layer of high swelling sodium bentonite, sandwiched between two geotextiles. Manufactured around the world by different techniques, Bentotex is mechanically bonded by needlepunching from one nonwoven geotextile through the bentonite to the other nonwoven or woven geotextile. Because of their low hydraulic conductivity, GCLs are used mainly as a replacement for thick, difficult to build, compacted clay liners to provide a barrier to liquids and gases.
Bentonite, named after an American geologist who discovered this type of clay in about 1890 in Fort Benton, Wyoming, is a clay mineral with expansive characteristics and low permeability, where montmorillonite is the chief mineral. Montmorillonite, named after a deposit located in southern France, swells when contacted with water approximately 900% by volume or 700% by weight. When hydrated under confinement, the bentonite swells to form a low permeability clay layer with the equivalent hydraulic protection of several feet of compacted clay.
In general installation consists of rolling out GCL panels on a prepared subgrade, with adjacent panels overlapped a minimum 300 mm. To maintain the integrity of the sealing system, a bead of granular bentonite is applied to the overlap of the adjacent panels. Subsequent to overlap treatment, a minimum 300 mm cover soil (or geomembrane in some cases) is placed. The covering material is always placed in the same shift (same day) as the GCL is deployed to minimize the chance of unconfined hydration, and possible damage to the GCL.
The technical properties of these materials are well documented and their integrity as a sealing barrier has been demonstrated in field applications. Furthermore, because these materials are factory produced, their properties are predictable, enabling the engineer to design with a high confidence level.