Fracture mechanics and asphalt binders

In this paper, the applicability of linear elastic, elastic plastic, and time-dependent (viscoelastic) fracture theories to asphalt binders at lower service temperatures is examined. Linear elastic fracture mechanics was found to be applicable only at temperatures below the glass transition temperature. Above the glass transition temperature, neither elastic nor elastic plastic fracture mechanics are applicable to asphalt binders because in this temperature regime they behave as time dependent viscoelastic materials and time-dependent fracture mechanics models must be used. Fracture parameters from each of the theories provide a different low temperature ranking of asphalt binders than the PG specification used in the United States. The authors conclude that, pending further development, the direct use of fracture mechanics parameters in a purchase specification is not realistic.