Geomembranes, the multipurpose Geosynthetics

What are geomembranes?

“Geo” means earth and a membrane is a thin layer, so a geomembrane is an impermeable sheet laid in or on the ground to contain liquids or gases. It is a geosynthetic liner. A geomembrane is far less permeable than compacted clay, and unlike concrete or asphalt it does not crack when the ground settles, which is why geomembranes are now the standard lining material in many industries.

The most common types of geomembranes are:

• High-density polyethylene or HDPE Geomembrane sheets
• Low-density polyethylene or LDPE Geomembrane (including linear low-density LLDPE)
• Ethylene propylene diene monomer or EPDM Geomembrane
• Polyvinyl chloride or PVC Geomembrane

Raw material and technology insights:

HDPE is the most widely used geomembrane polymer because it is economical, has very good chemical and UV resistance, and is easy to weld on site. More flexible polymers such as PVC, LLDPE and EPDM are chosen where the liner must follow uneven ground or settle without damage: they are less prone to stress cracking than HDPE and tolerate more strain.

Geomembranes are made by extrusion (polyethylene) or calendering (PVC and EPDM), which lets manufacturers produce sheets of different thicknesses, widths and surface textures for different uses. The right sheet for a job is chosen on physical properties (thickness, density, melt flow index, mass per unit area) and mechanical properties (tensile strength, tear resistance, puncture resistance, interface shear strength and stress crack resistance under constant load). For HDPE, the GRI-GM13 specification sets the minimum values.

Insight on Geomembrane Applications:

Geomembranes are strong and flexible, chemically inert, and formulated to resist UV, oxidation and extreme temperatures.

These are the most common applications in construction, transport, environmental and hydraulic works:

• Landfills: geomembranes are used in landfill liners, caps, temporary closures and covers, where their elongation and durability let them follow settlement without tearing. They contain municipal solid waste, low-hazard industrial waste, coal ash (including ash basin closures), cement kiln dust and construction and demolition debris.
• As Caps and Closures: as caps and covers, they control odour, stop rainwater infiltrating the waste, protect slopes from erosion, and serve as stockpile covers.
• Pond Liners: tough, flexible geomembranes make durable, cost-effective pond liners with a long service life. HDPE is widely used to line fish and aquaculture ponds; Ocean HDPE Liner 500 Micron was used at the ICAR-National Research Centre for Makhana in Darbhanga, Bihar.
• Mining: HDPE geomembranes line heap leach pads, tailings dams and process ponds, stopping leachate and process solutions from contaminating soil and groundwater.
• Canal Liners: PVC, HDPE, LDPE and EPDM geomembranes are all used to line canals and cut seepage losses.
• Oil and Gas Containment: geomembranes line secondary containment around tanks and oil pits. On side slopes, single- or double-sided textured sheets are used to increase the friction with the soil and cover layers.
• Other Uses: moisture barriers under floor slabs, waterproofing in tunnels and around pipelines, sports grounds and water reservoirs.

Future of Geomembranes, Industry Insights:

Demand for geomembranes is driven by growth in mining and construction and by stricter waste management and water-conservation requirements worldwide.

Choosing a geomembrane:

Geomembranes are used wherever liquids or gases have to be contained, most of all at municipal landfills, power plants and mining sites.

At Ocean Geosynthetics, we recommend a geomembrane for each site based on its physical and chemical conditions and the installation method, because these decide how well the liner performs and how long it lasts.

Get a Free Quote: Contact Ocean Geosynthetics for geomembranes for your project.

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