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为了避免采用分段函数的不方便性和弥补传统S-N疲劳方程分析宽应力比条件下沥青混合料疲劳特性的不足,揭示了应用反曲函数(Sigmoidal Function)描述宽应力水平下沥青混合料疲劳规律的适用性,通过原材料试验及配合比设计,确定了沥青混合料级配和最佳油石比,利用MTS810(Material Test System 810)对沥青混合料进行了较宽不同应力比下的疲劳试验,采用反曲函数对试验结果进行了拟合,建立了宽应力比条件下沥青混合料改进的S-N疲劳模型,利用该模型对疲劳寿命进行了预估,并与传统S-N模型预估结果进行了比较。结果表明:采用反曲函数建立的改进的S-N疲劳模型能模拟宽应力比条件下的沥青混合料疲劳规律,证实了其先进性,该模型各参数具有明确的疲劳物理意义,且其参数值容易获得。
In order to avoid the inconvenience of using the piecewise function and to make up for the insufficiency of the traditional SN fatigue equation to analyze the fatigue behavior of asphalt mixtures under the conditions of wide stress ratio, Sigmoidal Function is applied to describe the fatigue behavior of asphalt mixture under wide stress level The suitability of asphalt mixture was determined through raw material test and mix design, and the asphalt mixture gradation and the best ratio of stone to oil were determined. The fatigue test of asphalt mixture under wide and different stress ratio was carried out by using MTS810 (Material Test System 810) The fitting function was used to fit the test results. An improved SN fatigue model of asphalt mixture under wide stress ratio was established. The fatigue life was predicted by the model and compared with the traditional SN model. The results show that the improved SN fatigue model established by the sigmoid function can simulate the fatigue behavior of asphalt mixture under the condition of wide stress ratio and its advanced nature is confirmed. The parameters of this model have a clear physical meaning of fatigue and the parameters are easy to be measured obtain.