Consideration of Heat Transfer Characteristics in Thermal Stress Calculations of Asphalt Mixtures in the TSRST

The low-temperature performance of asphalt mixtures was a critical factor that investigated the thermal cracking of asphalt pavement in cold regions of the world. Many scholars have affirmed that the failure temperature of the thermal stress restrained specimen test (TSRST) could be an index to evaluate the low-temperature performance of asphalt mixtures. However, the influence of transient heat transfer on asphalt mixtures was ignored in the TSRST, potentially leading to inaccurate evaluation indexes for low-temperature performance. In this paper, the thermal contraction strain and the effective temperature of asphalt mixtures were analyzed considering transient heat transfer in the TSRST. First, the effective temperature and the thermal contraction strain were captured during the cooling process. Then, the calculation model of thermal stress was improved. The pseudo strain energy density was calculated based on the energy theory. Finally, the calculation model of thermal stress was evaluated with the failure temperature as the standard. The difference between the failure temperature calculated by the calculation model of thermal stress without considering the transient heat transfer and the failure temperature calculated considering the transient heat transfer was at least 2°C.