Comparisons of analytical and approximate interconversion methods for thermal stress computation

Abstract

In the northern US and Canada, low temperature cracking represents a significant distress for asphalt pavements. As temperature drops thermal stress develops in the restrained asphalt surface layer and when it reaches a critical value cracking occurs. For this reason, thermal stress is a crucial parameter for evaluating the low temperature pavement performance. Conventionally, thermal stress is computed by converting creep compliance into its corresponding relaxation modulus based on different techniques. In this paper, five analytical and approximate interconversion methods are used to obtain the asphalt binder thermal stress and the results are graphically and statistically compared. Clear differences in thermal stress are found when using power law based interrelationships in comparison with the numerical solution of the convolution integral according to Hopkins and Hamming’s algorithm. Nevertheless, the approximate methods provide a simpler approach for determining satisfactory upper and lower boundary limits when estimating the thermal stress of asphalt binder.