Long-term Performance of Conductive-backed multilayered HDPE Geomembranes

The long-term performance of three multilayered textured white conductive-backed geomembranes (GMBs) is compared to the comparable textured nonconductive GMBs and their smooth edge/equivalent to investigate the effect of the conductive layer on their longevity. Oven immersion in synthetic municipal solid waste leachate is used at a range of temperatures to accelerate the ageing during an incubation period of 50 months. It is shown that the conductive layer can antagonistically or synergistically affect the antioxidant depletion of conductivebacked GMBs relative to nonconductive GMBs produced by the same GMB manufacturer and formulated using the same nominal resin and antioxidant package. However, their relative degradation at 85 degrees C does not necessarily follow their relative antioxidant depletion times implying that the manufacturing process and the interaction between the additive packages of these GMBs can affect their relative degradation beyond the antioxidant depletion stage. Arrhenius modelling predicts the antioxidant depletion stage at field temperatures ranging between 180 and 1400 years at 20 degrees C for two different conductive-backed GMBs produced by two different manufacturers. With such variation in the long-term performance of conductive-backed GMBs currently available in the market, their durability should be investigated before their use in barrier systems to ensure they can meet the required design life of the desired geoenvironmental application.