利用Cooper NU-14试验系统评价沥青混合料疲劳性能

Evaluation of Fatigue Performance of Asphalt Mixture Using Cooper NU-14 Test System

目前国内采用的室内疲劳试验方法主要是间接拉伸法(即劈裂试验).鉴于其在加载方式与路面实际受力状态方面存在较大差别、实际开裂模式与理论开裂位置经常不一致,笔者尝试使用一种四点弯曲疲劳试验系统(即Cooper NU-14试验系统)评价沥青混合料的疲劳性能.文中详细介绍了试验设备、试件制作,试验参数设定,试验加载整个过程,对采用不同沥青类型的混合料以及SMA的疲劳性能进行了试验及定量对比分析.结果表明:该试验系统能有效地评价非均匀材质的沥青混合料疲劳性能,沥青结合料性质和集料级配对沥青混合料的疲劳性能都有非常重要的影响.

At present, the indirect tensile method （splitting test） is commonly used in China to test the fatigue performanee of samples. However, there exist obvious differences between the loading mode of the method and the actual stress state of pavement, and the actual cracking mode is often inconsistent with the theoretical cracking location. In order to solve these problems, a four-point bending fatigue test system Cooper NU-14 was used to evaluate the fatigue performance of asphalt mixtures. The whole process of the test, including the experimental facility, the specimen fabrication, the experimental parameter setting and the loading, was described in detail, and the fatigue performances of the mixtures with different asphalt types and stone matrix asphalt were tested and quantitatively compared. The results show that the testing system effectively evaluates the fatigue performance of inhomogeneous asphalt mixtures, and that both the properties of the binder and the aggregate gradation significantly influence the fatigue performance of asphalt mixtures.