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为了弥补现行沥青路面设计规范在利用传统疲劳方程进行疲劳设计时的不足,通过对沥青混合料进行不同程度的长期老化试验模拟了路面实际的老化程度。通过不同加载速率下的沥青混合料强度试验,揭示了强度随加载速率的变化规律。基于不同加载速率下的强度值,得到了与疲劳加载速率对应的疲劳真实应力比,建立了基于名义应力比和真实应力比的沥青混合料疲劳方程。基于名义应力比的疲劳方程曲线后延后与横坐标的交点远比1大,不具有后延性,而基于真实应力比的疲劳方程曲线可以后延到疲劳寿命为1的强度破坏点,统一了强度破坏与疲劳破坏的内在联系。建立了基于真实应力比的老化沥青混合料疲劳方程,疲劳方程曲线均通过(1,1)点。研究结果可为沥青路面设计时考虑老化效应的影响和抗拉强度结构系数的正确计算提供理论方法和依据。
In order to make up for the shortcomings of the current asphalt pavement design code when using the traditional fatigue equation for fatigue design, the actual aging degree of the pavement is simulated through long-term aging test of asphalt mixture to different degrees. Through the asphalt mixture strength test under different loading rates, the variation of strength with load rate was revealed. Based on the strength values under different loading rates, the fatigue true stress ratio corresponding to the fatigue loading rate was obtained, and the fatigue equation of asphalt mixture based on the nominal stress ratio and the true stress ratio was established. The fatigue stress equation based on the nominal stress ratio is far behind the post-curve extension point of intersection with the abscissa and lacks ductility. However, the fatigue stress curve based on the true stress ratio can be postponed to the strength failure point with fatigue life of 1 The relationship between strength destruction and fatigue damage. The fatigue equation of aged asphalt mixture based on true stress ratio was established, and the fatigue equation curve all passed (1,1). The research results can provide theoretical method and basis for considering the effect of aging effect and calculating the structural coefficient of tensile strength in asphalt pavement design.