The novel asphalt concrete waterproofing layer (ACWL) in high-speed railway faced a severe challenge from thermal fatigue cracking, while there was absence of a feasible evaluation method for this unique thermal fatigue mode. In this study, the overlay test (OT) was customized in terms of test temperature and open displacement to simulate the cyclic thermal load on in-service ACWL and characterize the thermal fatigue behaviors of railway asphalt mixtures. Four classical and two dissipated energy-derived indicators, namely maximum tensile load (L0), cracking rate index (CRI), the ratio of transitional tensile load L1 to L0 (L1/L0), pseudo fracture energy (PFE), initial dissipated energy (IDE), and cumulative dissipated energy (CDE), were utilized to evaluate the fatigue characteristics. It was found that the OT at a test temperature of 20 °C and open displacement of 0.6 mm was the most efficient in distinguishing fatigue characteristics, and the CRI, L1/L0, IDE, and PFE were statistically recognized to be feasible and effective. In addition, railway asphalt mixtures could achieve a 10-year fatigue life under moderate conditions while might crack rapidly at a low temperature and a large open displacement. Meanwhile, several indicators, including L0, CRI, L1/L0, PFE, and CDE, demonstrated linear relationships with the fatigue life on a normal or log scale at low temperatures, implying their potential to predict fatigue life. Finally, a Weibull damage model was applied based on load ratio-based damage degree, which had fair linear correlation with actual damage degree, to correlate with the thermal fatigue damage process. As expected, the proposed evaluation method, indicator, and fatigue damage model could fairly characterize the thermal fatigue behaviors of railway asphalt mixtures and further guide the construction and maintenance of ACWL.

高速铁路新型沥青混凝土防水层（ACWL）面临着热疲劳开裂的严峻挑战，而这种独特的热疲劳模式缺乏可行的评价方法。在这项研究中，根据测试温度和开放位移来定制覆盖测试（OT），以模拟在役 ACWL 上的循环热载荷并表征铁路沥青混合料的热疲劳行为。四个经典和两个耗能衍生指标，即最大拉伸载荷（L0）、开裂率指数（CRI）、过渡拉伸载荷L1与L0的比值（L1/L0）、假断裂能（PFE）、初始耗散能(IDE) 和累积耗散能量 (CDE) 用于评估疲劳特性。发现在20°C的测试温度和0.6 mm的开放位移下的OT在区分疲劳特性方面最有效，CRI、L1/L0、IDE和PFE在统计上被认为是可行和有效的。此外，铁路沥青混合料在中等条件下可达到10年的疲劳寿命，而在低温和大开口位移下可能会迅速开裂。同时，包括 L0、CRI、L1/L0、PFE 和 CDE 在内的几个指标在低温下与正常或对数尺度的疲劳寿命呈线性关系，暗示它们具有预测疲劳寿命的潜力。最后应用基于载荷比的损伤程度与实际损伤程度具有良好线性相关性的Weibull损伤模型与热疲劳损伤过程相关联。