Construction grade expanded polystyrene (EPS), or geofoam, is dimensionally sensitive to hydrocarbons and is typically covered with a protective polyolefin geomembrane when used as a foundation material. Data has been generated showing that the geomembranes currently used in construction applications provide less protection than initially assumed, with liquid fuels diffusing through some in as little as 4 hours. Enhanced protection for EPS geofoam foundations can be achieved using barrier geomembrane products, which utilize multilayer polymer geomembrane technology for increased protective performance. Fuel spill experiments using a variety of geomembranes (composed primarily of either linear low density polyethylene (LLDPE), high density polyethylene (HDPE), ethylene interpolymer alloy (EIA), polyvinyl chloride (PVC), or chlorosulfonated polyethylene (CSPE-R)) show these geomembranes to have poor permeation resistance to gasoline, resulting in rapid degradation to encased blocks of EPS geofoam in only a few hours. In contrast, a multilayer barrier geomembrane was shown to provide considerable advantage in protecting the EPS foam by preventing gasoline permeation for over 1000 hours of continuous exposure. Additional testing has further demonstrated complete protection of the geofoam can be achieved even after 160 days (3840 hours) of exposure to gasoline.
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