The long-term performance of a bituminous geomembrane (BGM) under single-sided exposure conditions

A custom-designed apparatus (referred to as the Ageing Column) is used to age a 4.8-mm thick elastomeric bituminous geomembrane (BGM) under single-sided exposure to a synthetic municipal solid waste (MSW) leachate and a synthetic high pH mining solution (pH 11.5) at 55, 70, and 85°C. This apparatus involves a closer simulation of the BGM’s chemical exposure conditions in the field than the double-sided immersion tests in which the BGM is exposed to the solution from both surfaces. The mechanical, rheological, and chemical properties of the BGM are examined to assess the degradation in the BGM components relative to double-sided immersion experiments. While the single-sided ageing of the BGM reduces the degradation rates in the BGM mechanical properties, it does not affect the degradation rate of the bitumen coat relative to the double-sided exposure. Additionally, the exposure of the BGM to the MSW leachate resulted in faster degradation in its mechanical properties but slower degradation in the bitumen coat than that obtained in the exposure to the mining solution. However, predictions of the time to nominal failure of the BGM established using Arrhenius modelling at different temperatures show that the temperature effect is more significant on the BGM durability than the chemistry of the considered solutions.