The aim of this paper is to investigate the performance of polyvinyl chloride (PVC) geomembranes used in the rehabilitation of European dams, particularly in Italy and in France. In all these applications, the geomembranes have been left exposed on the upstream face, without external protection, to environmental factors and atmospheric agents, especially to UV rays, even at very high elevation on the Alps.

To verify the effective performance of the barrier system over time, several geomembrane samples have been taken from a considerable number of dams, both in Italy and in France. These samples have then been subjected to destructive physical and mechanical tests, to allow the study of the evolution of the properties of the geosynthetics over the years.

In a lot of cases, particularly when the results of tests on virgin samples were available, it was possible to evaluate the residual life of exposed geomembranes on the different types of dams.

In fact, the prediction of the time in which it could be eventually necessary to replace the geomembrane becomes of a crucial importance also for the owner of the dam.