拉-压交变荷载下沥青混合料的疲劳性能

Fatigue Performance of Asphalt Mixture Under Tensile-compressive Alternating Loading

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。

To study the effect of tensile-compressive alternating loading on the fatigue damage of asphalt mixture, a new kind of loading device was developed. Taking AC-25F and AC-16C as research targets, fatigue tests at various loadings and stress ratios were conducted. The effect of the loading level and compressive strain on the fatigue performance of asphalt mixture was analyzed. A fatigue prediction model was set up which would consider the influence of compressive stress based on the test data. The results show that there is a logarithmic linear relationship between the fatigue life and tension stress~ however, the compressive stress significantly extends the fatigue life of asphalt mixture; for AC-25F, the fatigue life at the stress ratio of --0.5, --0.3 and --0.1 is 2.52 times, 1.53 times and 1.03 times stress ratio of 0 respectively. ~ 1 respectively; for AC-16C, it is 4. 90 times, 3. 31 e fatigue prediction model effectively makes up for the models which only consider the influence of compressive stress, and can pavement structure design and fatigue prediction. of the fatigue life at the times and 2. 30 times defects of the existing provide a reference forpressive alternating loading