PVC geomembranes in dams: influence of test temperature on seams peel and shear strength

Abstract

The PVC geomembranes are the most commonly used for dams. The success of this waterproofing system depends on the quality of which the geomembranes seams are made. The seams must be evaluated in terms of continuity/watertightness and mechanical strength, the latter being assessed by peel and shear tests. In this work, the imfluence of test temperature on the peel and shear strength of PVC geomembrane seams 1s studied. This issue is Important because, sometimes 1n the field, 1t 1s not possible to carry out these tests at the standard temperature of 23ºC (+ 2ºC), raisimg questions on their acceptance/rejection. Three geomembranes (1.5 mm, 2.0 mm and 3.0 mm thickness), with dual track thermo-fusion seams, were evaluated by peel tests according to ASTM D 6392 standard, at temperatures ranging from 5ºC to 41 “CC. One of the geomembranes (3.0 mm thickness) was also tested by shear tests, according to the same standard. Results showed that test temperature has a small influence on the peel strength values of the PVC geomembrane seams, contrary to what happens with HDPE geomembranes. Results also showed a significant decrease in shear strength with increasing test temperature, as was also verified with HDPE geomembranes.