Viscoelastic Response of Asphalt Concrete Pavement under Ambient Temperature Periodic Variation

摘要

Due to the variation of ambient temperatures, thermal stresses develop in pavement structures. The ambient temperature not only changes daily and seasonally, but also over yearly cycles. By combining field data, thermodynamic theory, and a three-dimensional finite element method, the viscoelastic response of asphalt concrete pavement under temperature variation was researched. The results of this study provided multiple insights to the behavior of the pavement under seasonal temperature changes. First, the development of thermal stresses followed a similar trend as the variation of ambient temperatures, but with a time lag. Second, the thermal stresses developed in the cold seasons were greater than those in the hot seasons. Third, in the top layers of the pavement, the range of thermal stress variation during a one-day period was greater than in the bottom layers. However, during the cold seasons, the bottom layers were more influenced by the thermal stresses compared to the top layers. Fourth, during the hot seasons, the stress relaxation effect of asphalt concrete was much more apparent. Finally, by deriving the stress relaxation equations, it could be demonstrated that, no matter what kind of load is applied to the viscoelastic material, the stress relaxation effect is only related to the intrinsic relaxation time of the material.