Fatigue life is one of the most critical factors for asphalt pavement design, which is directly affected by the fracture properties of asphalt mixtures. This study aimed to present a mechanistic framework to determine the Paris’ law parameters $A^{\prime }$ and $n^{\prime }$ of asphalt mixtures and fatigue life of asphalt pavements. The dynamic modulus test and indirect tensile (IDT) test results were obtained from Texas Data Storage System (DSS) to evaluate the linear viscoelastic properties and fracture properties. Modified Griffith crack criterion in tension was used to determine the damage density rate and pseudo J-integral of macrocracks appeared in the post-peak phase of the IDT test, and the damage density with time was shown as a sigmoidal shape from microcracking initiation. The Paris’ law parameters were then computed using the regression analysis in the macrocracking stage. It was shown that the fracture resistance of asphalt mixtures could be characterized using $n^{\prime }$, and a smaller value of $n^{\prime }$ indicates a better fracture resistance. The mode-I fatigue life equation for reflection cracking in asphalt pavements was also proposed based on the J-integral from the finite element model and Paris’ law parameters, which shows that the empirical fatigue life transfer function could also be determined from actual material properties and pavement structural boundary conditions.

疲劳寿命是沥青路面设计最关键的因素之一，它直接受到沥青混合料的断裂性能的影响。本研究旨在提出一个机制框架来确定巴黎的法律参数${\mathrm{一种}}^{\prime }$ 和 $n^{\prime }$沥青混合料与沥青路面疲劳寿命的关系。动态模量测试和间接拉伸（IDT）测试结果来自德克萨斯数据存储系统（DSS），以评估线性粘弹性能和断裂性能。采用拉伸中修正的 Griffith 裂纹准则来确定 IDT 试验峰值后阶段出现的宏观裂纹的损伤密度率和伪 J 积分，从微裂纹萌生开始，损伤密度随时间的变化呈 S 形。然后在宏观裂纹阶段使用回归分析计算巴黎定律参数。结果表明，沥青混合料的抗裂性可以用$n^{\prime }$，以及较小的值 $n^{\prime }$表明具有更好的抗断裂性。基于有限元模型的J积分和Paris定律参数，提出了沥青路面反射开裂的I型疲劳寿命方程，表明经验疲劳寿命传递函数也可以根据实际材料特性确定和路面结构边界条件。