What Is a Geomembrane?
A geomembrane is a synthetic liner used to control the migration of fluids or solid waste in human-made projects and structures. These impermeable membranes are typically made from formulations of polyethylene or polyvinyl chloride.
HDPE is popular for its UV and temperature resistance, low material cost, and durability; LLDPE offers more flexibility compared to HDPE. Both are produced using either extrusion, calendering, or spread coating.
Waterproofing
Geomembrane is a modern waterproof geotechnical material that provides reliable protection against leaks in structures such as ponds and reservoirs. Its water resistance, puncture and tensile strength, and chemical resistance allow it to function geomembrane well in various environmental conditions. It is often used in conjunction with soil liners and permeable geotextiles to create a composite lining system that can prevent the migration of contaminants from one area to another.
Depending on the specific project requirements, the geomembrane may be manufactured using different materials including high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), or Ethylene Propylene Diene Monomer (EPDM). The selection of the most suitable material for a particular project requires a thorough evaluation of ground conditions and local climate. Once the appropriate material has been selected, it must be properly prepared and placed with a precision that prevents water leakage.
Geomembrane installation can be complex and requires professional training to ensure the work is carried out correctly. A geosynthetic release sheet is also available to help protect the geomembrane during installation, preventing fine particles from building up in the seaming areas and potentially causing damage. This release film is removed directly prior to seaming, enabling welding with hot air instead of heat, which is more effective in eliminating contamination and maintaining the integrity of the geomembrane. Moreover, geomembrane is made from non-toxic materials and can be easily recycled when its lifecycle comes to an end.
Drainage
Whether it’s clean water, wastewater, vapor, soil or hazardous waste, a geomembrane restricts the flow of materials that shouldn’t leave its designated space. This function makes it ideal for water storage reservoir construction, agriculture and irrigation projects, landfills and waste management, mining, and environmental protection projects.
The material’s strength and durability help it withstand physical strains such as puncture, bending, and abrasion, as well as environmental stresses, like differential settlement. It also resists temperature fluctuations and oxidation, with the ability to withstand exposure to UV radiation for many years.
Another important feature of geomembranes is their drainage capabilities. For landfills and other waste-related applications, a protective layer is often placed under the geomembrane to keep it from direct contact with gravel or other abrasive material. The drainage system underneath the geomembrane can be a layer of sand, aggregates or a combination of these materials.
When it comes to installation, the most important factor is to ensure the geomembrane is protected against the damage caused by the abrasive elements, as well as any penetrations or movement of debris. Adding a protection layer is an effective way to prevent this type of damage, and Visqueen offers a variety of options to meet your specific needs. These include:
Chemical Resistance
Chemical resistance is the ability of a geomembrane to resist degradation processes that can destroy or weaken its structural integrity and ultimately reduce its functionality. This includes anything that causes polymeric chain scission, bond breaking or additive depletion within the geomembrane itself. Chemical degradation can cause the stress-strain behavior of a geomembrane to become brittle over time, which can then lead to part failure.
All geomembranes possess some level of chemical resistance, though it differs from one to the next. For instance, high-density polyethylene has a better level of chemical resistance than chlorosulfonated polyethylene (CSPE).
The primary factor that determines how well a geomembrane will resist chemicals is its polymer composition. A geomembrane’s ability to withstand the effects of chemicals also depends on its temperature, concentration and exposure duration. Additionally, mixtures of chemicals often affect a geomembrane’s chemical resistance in ways single chemicals do not.
Geomembrane’s chemical resistant capabilities make it ideal for use in landfills to control leakage and minimize environmental pollution. It is also frequently used in mining areas for waste containment and wastewater treatment systems, as well as for water storage reservoirs and irrigation channels.
RPP, EPDM and XR are the three most commonly Slope Protection Geocell Used used types of geomembrane. RPP is a polyester-reinforced liner that is incredibly durable and ideal for long-term water containment. EPDM is a rubber-like material that is highly durable and offers great flexibility. XR is an ethylene interpolymer alloy reinforced woven synthetic fabric that is exceptionally durable and offers exceptional flexing and strength.
Durability
A geomembrane should be able to sustain the environmental conditions and mechanical stresses associated with its application environment. This means it must be able to withstand UV degradation, abrasion, punctures, chemicals and other potential contaminants. It should also be able to maintain its structural integrity after installation and provide adequate resistance to tensile, compressive, and lateral loads.
Durability is essential for long-term success in landfills, mining applications, water conservation projects and other industrial applications. Durable liners are designed to minimize leaks and offer exceptional chemical resistance. They also have superior tear strength that prevents rupture and can resist abrasion from sharp or abrasive objects. The material must also be able to withstand temperature variations to prevent brittleness and other negative effects.
The durability of a liner is determined by the thickness and quality of the materials used. High-density polyethylene (HDPE) offers greater strength, stiffness and abrasion resistance than low-density polyethylene (LDPE). It is also able to withstand higher temperatures without degrading or becoming brittle. However, HDPE is susceptible to cracking and tearing if exposed to abrasive surfaces and must be coated with a geotextile to reduce this risk. Other factors that can impact a geomembrane’s longevity include temperature, chemical exposure, oxidation, swelling and extraction degradation. Each of these phenomena can decrease the longevity of a liner, but they can be monitored through mechanical testing.
