An alternative method for determining thermal stress in asphalt binder based on laplace transform

Low temperature cracking is one of the most severe distresses for asphalt pavement experiencing severely cold weather conditions. As temperature drops, significant tensile stress develops in the restrained asphalt layers, and, when the material strength is overcome, cracking occurs. Many road authorities recognize thermal stress as a crucial parameter for evaluating the low temperature performance of asphalt pavement. Thermal stress is conventionally computed with a two-step approach where the relaxation modulus is derived from the experimental creep compliance after which the convolution integral is numerically solved. In this paper, a one-step computation solution based on Laplace transformation is proposed. Thermal stress and corresponding critical cracking temperature of asphalt binder are computed and graphically and statistically compared to the values obtained with traditional approach. It is observed that use of Laplace transformation provides reasonably close results to those obtained with the conventional two-step solution.