EPDM for wrinkle-free closure system

EPDM rubber (ethylene propylene diene monomer (M-class) rubber) is an extremely durable synthetic rubber membrane that is widely use for building and infrastructure applications. EPDM has two primary ingredients, ethylene and propylene, which are derived from oil and natural gas. EPDM is available in both black and white, and is sold a broad variety of widths. The material can be installed or attached mechanically or ballasted. Such flexibility and durability has rendered EPDM a material of choice for a growing number of applications in various industries.

The EPDM rubber roofing membrane has been an appealing choice of the low-slope commercial roofing industry for decades. EPDM has been preferred for both new construction and replacement roofing projects, according to EPDM Roofing Association. The greatest test of any construction material is how it performs under actual field conditions. Forty years of empirical experience in field applications has shown EPDM to have the roofing industry’s longest average service life.

Improved environmental impact

LiteEarth is the latest product to enter the landfill closure market, and consists of an EPDM geomembrane factory bonded to synthetic grass using an industrial grade adhesive. Testing has confirmed that LiteEarth is a robust material with a much greater thickness and mass than polyethylene geomembranes and drainage geocomposites alone, which lends an intrinsic resistance of the material to waves, wrinkles and damage.

When closing landfills and other earth reclamation projects, waves and wrinkles in the material can lead to long-term structural and environmental damage. Due to its low coefficient of thermal expansion, as well as its unique components, LiteEarth will remain in a wrinkle-free state when used in interim or long-term closure applications.

“Expansion and contraction with LiteEarth will be much smaller than polyethylene,” said Dhani Narejo, P.E., Ph.D., President of Narejo, Inc. “We have determined that the high mass of the material, when combined with synthetic grass and a low coefficient of thermal expansion, makes it possible for LiteEarth to remain wrinkle free.”

According to the Geosynthetics Institute GSI White Paper #27, co-authored by Dr. Robert Koerner and Dr. George Koerner, wrinkles and waves in a geomembrane can result from expansion and contraction when exposed to temperature change, and are primarily related to the type of material as well as its stiffness and thickness. Due to its higher coefficient of thermal expansion, polyethylene geomembranes such as HDPE and LLDPE are prone to wrinkling and waves.

Waves and wrinkles on the surface of landfill closure can be troublesome for several reasons. As wrinkles develop and fold over each other, pressure can cause cracking of the surface, leading to water or methane gas leakage through the geomembrane. Uneven stresses by the waves can also cause distortion and structural damage to the underlying clay liner, and lead to possible shortened lifespan of the cover. Further, wrinkles and waves on down slopes often pool with water, making any repairs particularly difficult.

The GSI White Paper #27 states that, “In the end, a ‘no wave’ strategy will result in a greatly improved environmentally safe and secure liner system.”

The LiteEarth system is applicable for long-term closure of Municipal Solid Waste (MSW), Coal Combustion Residuals (CCR) and other Monofils and Mining, and exceeds the infiltration and erosion requirements for a Final Cover as specified in RCRA Subtitle D. Further, when placed under high temperatures, LiteEarth has shown excellent linear dimensional performance, tensile strength, elongation and tear resistance, and has a temperature range of -49°F to 241°F.

LiteEarth is an advanced, engineered and fully-tested earth capping system that exceeds the infiltration and erosion requirements for a Final Cover as specified in RCRA Subtitle D. The patent-pending turf closure system permanently combines synthetic turf and EPDM geomembrane into a long-lasting composite using an industrial grade adhesive. The result is an efficient, economical and environmentally-responsible solution with very low installation and life cycle costs. The system has been fully tested according to ASTM and regulatory standards. LiteEarth synthetic turf is manufactured by industry leader Act Global.