The strange effect of increasing temperature in accelerated ageing of HDPE geomembranes immersed in liquids

By: Fady B. Abdelaal

Abstract

The most commonly used temperatures for accelerated ageing of HDPE geomembranes (GM) is at or below 85o. This study examined geomembrane ageing in air, water and leachate at 95, 105 and 115oC. Ageing in air was accelerated as expected at higher temperatures. For liquid immersion tests, very different results were obtained from tests in sealed stainless steel tanks (with a pressure release valve) and glass jars open to atmospheric pressure. The antioxidant depletion rates for GMs immersed in leachate using stainless steel tanks were not consistent with what observed at low temperatures. However, for the glass jars the results fitted well with the low temperature results. This suggests that vapour pressure may affect GM ageing.  However, even with glass jars open to atmospheric pressure, ageing of GMs in water gave unusual and unexplained results.