Measuring Uplift Resistance of Asphalt Shingles
SourceThe uplift resistance of asphalt shingles with self-sealing adhesives is studied by applying mechanical forces to examine the effects of loading geometry, shingle rigidity, and the rate of load application. Three distinct test methods for simulating the wind-induced uplift effects of peeling, pulling, and its combination are used to study the sealant performance as a function of shingle rigidity and the rate of loading. The results show that the measured sealant strength is significantly influenced by the test and loading configurations, as well as by the loading rate. The current ASTM D 6381 test, which measures the uplift resistance under mechanical peeling action, is found to yield relatively low measured sealant strength as compared to the other test method intended to simulate wind uplift effects according to current wind-uplift force model. Fracture analysis and fractography conducted on test specimens reveal that the measured shingle uplift resistance is significantly increased under high deformation rate due to a transition from failure inside the asphalt coating to adhesive fracture in the sealant by cavitation mechanism.