ABSTRACT
This contribution presents the recent results of an ongoing research on the long-term behaviour of a PVC-P geomembranes installed on the upstream face of masonry and concrete dams. In the last 30 years, starting from sometime after the dam rehabilitation with this type of geosynthetics, the exposed PVC-P geomembrane were sampled periodically and tested in laboratory. Material properties measured at the laboratory were compared with the ones obtained from test on virgin samples, when available. The sampled geomembranes have been subjected to physical and mechanical tests and the results interpreted with reference to the variation of plasticizer, tensile characteristics, foldability at low temperatures, and specific mass. In particular, the decrease in plasticizer content resulted in a slightly increase of the geomembrane rigidity, i.e. higher modulus and tensile strength and lower strain at failure. The experimental program allowed to study the evolution of the properties of the geomembrane over the years enabling the assessment of the residual life of exposed geomembranes installed on the upstream face of dams.
