Effect of Thermal Stresses on Pavement Performance under Mild Climate Conditions

Abstract

Thermal stress on the surfaces of pavements located in mild climates has been commonly considered to have a negligible effect on pavement performance. Current pavement design methodology focuses on maximum tensile stress rather than tensile stresses occurring over the design life of pavements. To identify the significance of thermal stress on pavement performance through structural stress analysis, this study investigated the predictive capability of the enhanced integrated climate model by comparing it with measured temperature data and introducing an analytical methodology of estimating thermal stress development using the dynamic modulus test. The identified thermal stresses were compared with the tensile stresses occurring at the bottom of an asphalt layer through the analysis method employed in the Guide for Mechanistic–Empirical Design of New and Rehabilitated Pavement Structures. Damage caused by the thermal and bottom stresses was evaluated on the basis of the damage ratio derived from the hot-mix asphalt fracture model. The conclusion drawn from the investigations was that the effect of thermal stress on pavement cracking performance, evaluated through the damage analysis considering the time-and temperature-dependent nature of asphalt mixtures, is much less significant than that of bottom stress under mild climate conditions. Under the nonaging condition, 1-year average damage occurring due to thermal stress at typical pavement structures would be slightly less than 0.5% of that which would be expected to occur at the bottom.