ABSTRACT
Geomembranes (GMs), especially high-density polyethylene (HDPE) ones, are used to provide a barrier to water and oxygen in mine site reclamation cover systems. The physical stability of these GM remains a major concern as it affects their performance to control fluid flows. Considering that HDPE GMs can crack even while being in the elastic domain, a maximum allowable strain (MAStrain) was fixed at 4% to avoid stress cracking. The MAStrain corresponds to a maximum allowable stress that must not be exceeded. This paper assessed the chemical and mechanical properties of exhumed GMs from two cover systems installed 13 and 20 years, and the impact of the tensile properties on the MAStrain. The results show that the GM remains in the first degradation stage and no negative impact was found on the mechanical properties. The tensile behavior of the exhumed GM indicates a gain of stiffness that reduces the MAStrain.
