Analysis of Natural Environmental Freeze-Thaw Cycles along the Qinghai-Tibet Highway

Nearly 60 years of meteorological data from six regions along the Qinghai-Tibet Highway is used to analyze the variation trends in natural environmental freeze-thaw cycles. The difference between the indoor freeze-thaw cycle test and freeze-thaw effect of actual environment is compared in this research. The classification criterion of freeze-thaw intensity is proposed based on the impact of freezing temperature and melting temperature, and freeze-thaw intensity is divided into two main types: weak freeze-thaw and strong freeze-thaw. The variation trends of monthly freeze-thaw cycles, and annual freeze-thaw cycles are analyzed. Comparison of freeze-thaw cycles in the six regions are carried out to illustrate the difference of natural environmental freeze-thaw cycles along the Qinghai-Tibet Highway. Results indicate that the freeze-thaw effect is still the main factor influencing the performance of asphalt pavement in cold regions of Qinghai-Tibet Plateau, and freeze-thaw should receive high attention during the pavement design, construction, and maintenance.