HDPE geomembrane”s behaviour after 20 years in service at Areias de Vilar Water Reservoir

Abstract

A high-density polyethylene geomembrane installed 20 years ago at Areias de Vilar Water Reservoir has experienced degradation and damages, such as tears, punctures and stress cracking. In order to study its behaviour, samples were taken from the west cell, from the four slopes, in two locations (above and below the water level). Tensile tests, static puncture tests and standard (Std) oxidative induction time tests (OIT) were carried out. The results show that the tensile strength at yield, the strain at break and the puncture resistance of the geomembrane remain close to the 1ts initial values, while the tensile strength at break and the strain at vield showed a decrease. Also Std-OITs measured were low and approaching a residual value.