Bentofix Coated GCLs: What is a geosynthetic clay liner and how does it work?

What is a geosynthetic clay liner (GCL)?

Geosynthetic clay liners (GCLs) are wide width rolls of bentonite clay sandwiched between layers of geotextile.

GCLs are an engineered replacement for traditional clay lining of containment structures, offering a neater, easier and more robust way to cap landfill cells, enclose contaminated soil, and contain water for environmental protection.

The use of these liners in civil and environmental applications is becoming more widespread as the industry develops a greater understanding of the effects of contaminated ground conditions on structures and the environment.

Bentofix® Thermal Lock geosynthetic clay liners (GCLs) are needle-punched, reinforced composites that combine two durable geotextile outer layers and a uniform core of high-swelling powder sodium bentonite clay. This forms a uniform, multi-directional, shear-resistant hydraulic barrier with self-sealing and re-healing characteristics.

How do GCLs work?

Bentofix® Geosynthetic Clay Liners contain a sodium bentonite powder that is processed to exceed all requirements of local and International standards for bentonite quality. The use of powdered sodium bentonite ensures positive hydration and hence compliant sealing properties.

This ability to hydrate and efficiently seal off the underlying soil or material means that gas, leachate and other liquids will not pollute the layer above the product.

The needle-punched thermally locked Bentofix® Geosynthetic Clay Liner is available in a polyethylene-coated variety with options for coating thickness and coating texture. The polyethylene is extrusion-applied to form an intimate bond with the Bentox® GCL substrate. This innovative development reduces the risk of desiccation, cation exchange, gas emission and potential bentonite erosion loss issues of lower quality GCL products.

This means the Bentofix® Geosynthetic Clay Liners provide immediate swelling and long-term performance once installed.

Common Applications of Geosynthetic Clay Liners

• Waste and contaminated soil caps

• Landfill base liners

• Gas and vapour seals

• Surface impoundment liners

• Secondary containment

• Dams, canals, and water courses

• Tailings containment

• Groundwater protection

• Vertical barriers

• Waterproofing

Why choose GCLs over compacted clay?

• Offers the designer an engineered equivalency to clay without the costly import and placement and quality control costs associated with this traditional method.

• GCLs can significantly increase the volume of containment, as the product offers equivalency to very thick layers of compacted clay.

• Economic alternatives to compacted clay.

• Wide width rolls make for quick installation.

• Product stocked locally in Australia for fast delivery to site

What types of GCLs are available?

Global Synthetics can offer a wide range of liners that are compatible with the diverse range of applications and contaminants likely to be encountered.

Coated GCLs

Bentofix® X Series Coated GCL features an additional surface polyethylene coating, which is applied in a liquid state and then allowed to solidify on the carrier geotextile.

The additional bonding of a PE coating to the needle-punched, fibre reinforcement is permanently locked, which increases the pull-out resistance as well as the internal shear strength.

The polyethylene extrusion coating ensures an immediate and enhanced barrier to gas and radon while protecting against desiccation and critical substances. In applications with high hydraulic gradients over coarse soils, the additional multicomponent GCL Bentofix® X coating prevents bentonite piping. In other applications, the barrier acts as a root barrier.

Other GCLs

Along with this popular coated variety, Global Synthetics also supplies standard, texture-coated and scrim-reinforced products for specific applications.

Contact Global Synthetics for advice on GCL selection

Our engineering team is here to assist you in choosing the right product for your project – get in touch for specifications and pricing and take advantage of our fast delivery Australia-wide.