Service life of HDPE geomembranes subjected to elevated temperatures

Subtitle D landfills may experience elevated temperatures for a variety of reasons such as hydration of combustion ash, waste biodegradation with and without leachate recirculation, aluminum production waste and combustion ash reactions, and wastes received with elevated temperature. Elevated temperatures can reduce service life or effectiveness of high density polyethylene (HDPE) geomembranes by accelerating antioxidant depletion of geomembranes and polymer degradation. A case history is presented to illustrate the potential effects of elevated temperatures and time-temperature history on a HDPE geomembrane and the associated reduction in service life or effectiveness. The geomembrane service life was influenced by the peak temperature, e.g., 60-80°C, the duration of peak temperatures (time-temperature history), and the time to complete antioxidant depletion. This paper also discusses possible criteria for assessing the service life of geomembranes, such as applicable engineering properties, locations for service life assessments, definitions of geomembrane service life, and measures that could be adopted if service life were reduced significantly.