Geosynthetic Clay Liner

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Geosynthetic Clay Liner

GCLs are factory manufactured hydraulic barriers consisting of a layer of bentonite clay supported by geotextiles and/or geomembranes mechanically held together by needling or stitching. These are often used to augment or replace compacted clay liner materials in landfill and SUDs pond applications.

The core of GCL is a uniform layer of natural sodium bentonite clay that swells when it comes into contact with water. This creates a low permeability barrier, with the same hydraulic protection as several feet of compacted clay.


Geosynthetic clay liner is a type of hydraulic barrier manufactured with a combination of low-permeability materials and supporting geotextiles and/or geomembranes mechanically held together by needling, stitching, or chemical adhesives. This makes it a superior choice for containment solutions. The primary benefit of this type of liner system is that it helps to comply with the environmental laws set by regulating agencies.

The main component of the GCL is a layer of processed sodium bentonite sandwiched between two layers of composite geotextiles. When exposed to water, bentonite swells and creates a high-density diaphragm that is highly waterproof. GCLs offer a cost-effective alternative to conventional compacted clay liner systems for landfills, ponds, and other environmental containment systems. They also have a long lifespan and provide resistance to physical or chemical break-down in harsh environments.

Since sodium bentonite is a pure natural inorganic raw material, GCLs do not produce embrittlement or corrosion in contact with water even after a long period of time. This is an important factor in ensuring that the GCLs will continue to perform well for the life of the installation project. Bentonite GCLs are available in both NP needling and OF film covered versions. They are commonly used in civil engineering projects such as landfill lining, underground reservoirs, and adorning ponds. In addition, they are also suitable for anti-seepage projects of engineering buildings.

Fire Resistant

Geosynthetic clay liner Geosynthetic clay liner is used to contain liquids or gases in a wide range of civil engineering applications. This includes landfill lining and capping, reservoirs and canals, highway balancing reservoirs and retention ponds.

The material consists of a layer of sodium bentonite sandwiched between two layers of nonwoven geotextiles. This is made using the acupuncture method, which forms many small fiber spaces that are impervious to water. Using this method allows the construction of a waterproof pad that can withstand high hydraulic gradients.

This means that the liner can prevent contamination of water and other substances from entering the environment, as well as protect groundwater. Additionally, it is a fire resistant material, meaning that it can be used in applications where there may be a risk of fire.

BENTOMAT GCLs are also designed to be quick and easy to install. The mats are supplied in rolls that can be cut to size and laid on site with an overlap, requiring no expensive welding work. The required overlap area is marked on the mat during manufacture and loose bentonite granulate is strewn over the marked area to ensure a full sealing effect.

The ability to be easily installed in cold inclement weather conditions also helps to drive down installation costs. Additionally, the fact that no specialist welding is required makes the material a more cost effective solution than traditional compacted clay liners.

Secondary Containment

In the geoenvironmental industry, GCLs are widely used to provide hydraulic barriers in landfill cap construction. They are also a popular solution for secondary containment of hazardous waste at oil and gas facilities and in underground reservoir construction. They are resistant to degradation from environmental factors and can be made more durable by adding layers of geotextiles.

Sodium bentonite, also known as montmorillonite, is the main component of GCLs. It is a clay mineral that swells when it comes in contact with water. Unlike calcium-based bentonite, which expands to only three times its volume when it swells, sodium bentonite can expand up to five times its original volume when it absorbs water. This makes GCLs an optimal solution for landfill cap construction and leakage prevention.

GCLs are constructed by sandwiching a layer of low-permeability sodium bentonite in between two layers of geotextiles, one woven and one nonwoven, which are mechanically needle-punched together to provide shear strength. This makes them a strong and versatile alternative to compacted clay liners or geomembranes alone.

If a GCL is damaged, it can be repaired by cutting a “patch” from a new roll geotextile cloth suppliers of liner and placing it over the broken area. The patch should be anchored to the GCL with anchor bolts or covered with a minimum of 300mm of soil.


As engineers strive to balance engineering demands with environmental stewardship, new technologies like geosynthetic clay liner products play a key role in managing water and contaminants for the sake of both. These liners are a reliable and sustainable solution for containment of waste materials as well as providing secondary containment when a primary barrier system fails.

GCLs are a popular alternative to traditional compacted clay liners and are used as a component of landfill covers, base liners for roads and railways, soil stabilization, and other containment applications. They are characterized by their ability to control both advective and diffusive contaminant transport. In addition, they have unique self-sealing characteristics that lower the risk of failure due to unfavorable field and operating conditions.

Unlike conventional compacted clay liners, GCLs are made from bentonite that is both supported and encased by geotextiles or geomembranes. The low-permeability of the bentonite ensures a strong and durable barrier, while the high shear strength provided by the needlepunched geotextiles makes GCLs more resistant to damage during construction and use.

The versatility of GCLs also means that they can be used for a wide variety of applications in environmental, hydro-geotechnical, and coastal engineering projects. In fact, GCLs are becoming the preferred choice over traditional CCLs and geomembranes for lining landfills, composite liners, protection barriers, dams, canals, ponds, and other storage and containment structures.

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