The roles of glass fiber mat on the fracture toughness of asphalt shingles

The effect of temperature on the fracture resistance of asphalt coating and fiber glass shingles were studied by measuring their J-integral fracture toughness at crack-initiation and by examining their deformation and fracture mechanisms. The temperature effects on tensile properties were first presented and the role of glass fiber mat on the fracture behavior of asphalt shingles was also examined. The results showed that a ductile-brittle transition was observed for asphalt coating when tested at temperatures below 0 degrees C, which may suggest that asphalt shingles can become crack-susceptible at temperatures above the glassy transition temperature of asphalt. For fiber glass shingles, the glass fiber mat was found to have an important role on enhancing the asphalt coating's fracture toughness and on suppressing the ductile-brittle transition at low temperatures when sufficient amount of glass fibers were presented in the system. Observation on the deformation and fracture mechanisms of asphalt and shingle samples indicated that temperature has a strong effect. These results were discussed in conjunction with fracture toughness measurements using fracture mechanics principles.