Lifetime predictions of exposed geotextiles and geomembranes

A very frequently asked question regarding all types of geosynthetics is, ‘How long will they last?’ This paper answers the question for exposed geotextiles and geomembranes, assuming that they were properly designed and installed. Furthermore, it compares these new results to the earlier lifetime prediction results of a covered geomembrane. Nonexposed (or covered) lifetime conditions for a 1.5 mm thick high-density polyethylene (HDPE) geomembrane have previously been evaluated and published. Landfill incubation devices at four elevated temperatures of 85, 75, 65 and 55°C were used in the prediction in order to reach 50% of retained strength and elongation. Considering the three stages of (i) depletion of antioxidants, (ii) induction time, and (iii) 50% reduction in mechanical properties, the lifetime extrapolation was made down to 20°C. The 50% reduction value (called halflife throughout the paper) for this geomembrane under these conditions was approximately 450 years. Since the laboratory incubation ti...