Comparison of thermal stress calculated from asphalt binder mixture creep compliance data

Abstract

Low temperature cracking represents a significant problem in asphalt pavements built in Northern US and Canada. As temperature decreases rapidly, thermal stresses develop in the restrained surface layer and, when the temperature reaches a critical temperature, cracking occurs. In this thesis, statical analyses were used to compare thermal stresses that develop in an idealized asphalt pavement layer calculated from experimental data obtained with three different test methods: 1) Asphalt mixture creep test using Bending Beam Rheometer (BBR) 2) Asphalt mixture testing using Indirect Tensile Test (IDT) 3) Asphalt binder creep test using BBR and an empirical Pavement Constant Thermal stresses calculated using mixture BBR and mixture IDT data were reasonably identical. Thermal stresses calculated using binder BBR data and an empirical Pavement Constant were significantly different than the other calculated thermal stresses. The effect of physical hardening on thermal stress evaluation was investigated for a limited number of materials and it was found that this effect significantly affect thermal stress magnitude.