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该文利用梁式疲劳试验设备进行测试,研究HMA疲劳极限是否存在及其确定方法。通过采用PG64-22沥青和Superpave级配在最佳沥青含量下制作大量试件,在不同的应变水平下进行疲劳试验。结果表明HMA具有疲劳极限的特征,文中HMA疲劳极限约为100με。在测试数据基础上,分别采用幂模型、对数模型、指数模型和Weibull函数对疲劳极限预估方法进行研究。研究表明:试验室梁式疲劳测试需要超过1 000万次循环才能得到疲劳极限的较准确预估;对数模型较适合预估疲劳寿命低于5 000万次的情况;Weibull函数适合预估疲劳寿命接近或大于5 000万次以及试验应变高于疲劳极限的情况。
In this paper, beam fatigue testing equipment is used to test the existence of HMA fatigue limit and its determination method. A large number of specimens were produced at optimum bitumen content with PG64-22 bitumen and Superpave grading, and fatigue tests were performed at different strain levels. The results show that the HMA has the characteristics of fatigue limit, in this paper, the fatigue limit of HMA is about 100με. On the basis of the test data, the method of exponential model, logarithmic model, exponential model and Weibull function are respectively used to study the fatigue limit estimation method. The research shows that the laboratory beam fatigue test needs more than 10 million cycles to obtain a more accurate prediction of the fatigue limit; the logarithmic model is more suitable for estimating the fatigue life of less than 50 million times; the Weibull function is suitable for estimating fatigue Lifetimes close to or greater than 50 million and test strains above the fatigue limit.