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为了研究交变力学状态下沥青混合料的疲劳性能,开发专用加载设备,选择AC-25F和AC-16C两种材料作为研究对象,进行不同荷载级别和不同应力比下的疲劳试验,分析荷载级别和压应变对沥青混合料疲劳行为的影响,并建立考虑压应力影响的疲劳预估模型。结果表明:各种应力比下,沥青混合料疲劳寿命与拉应力呈对数线性关系,但压应力显著延长了材料的疲劳寿命。对于AC-25F,其在应力比为-0.5,-0.3,-0.1时的疲劳寿命分别为应力比0.1时的2.52倍、1.53倍和1.03倍;对于AC-16C,相应的疲劳寿命则分别为应力比0.1时的4.90倍、3.31倍和2.30倍;所建立的考虑压应力影响的疲劳预估模型可有效弥补现有模型仅考虑拉应力作用的缺陷,为路面结构设计和疲劳预估提供参考。
In order to study the fatigue behavior of asphalt mixture under alternating mechanical condition, a special loading equipment was developed. Two kinds of materials, AC-25F and AC-16C, were selected as the research object. The fatigue tests under different load levels and different stress ratios were performed to analyze the load level And the influence of compressive strain on the fatigue behavior of asphalt mixture, and establish the fatigue prediction model considering the influence of compressive stress. The results show that there is a logarithmic linear relationship between fatigue life and tensile stress at various stress ratios, but the compressive stress significantly prolongs the fatigue life of the material. For AC-25F, the fatigue life at stress ratio of -0.5, -0.3, -0.1 is 2.52 times, 1.53 times and 1.03 times respectively when the stress ratio is 0.1; for AC-16C, the corresponding fatigue life is 4.90 times, 3.31 times and 2.30 times higher than that of 0.1. The fatigue prediction model considering the effect of compressive stress can effectively make up for the defect that the existing model only considers the effect of tensile stress, and provide reference for pavement structure design and fatigue prediction .