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为获取钢桥面铺装环氧沥青混合料的疲劳衰变特性,首先基于正交异性桥面板-铺装层组成的复合结构模型,计算出标准胎压、超载50%以及超载100%胎压作用下铺装层的最大拉应变,作为疲劳试验应变水平的选取标准;然后,采用小梁四点弯曲疲劳试验对3组不同温度和不同应变条件下的环氧沥青混合料疲劳性能进行测试;最后,利用威布尔公式对不同温度与应变条件下的环氧沥青混合料疲劳寿命与疲劳裂纹扩展时的作用次数进行预测。结果表明:环氧沥青混合料初始模量大小仅与温度相关,与应变水平无关;在10℃和20℃时,1.38 MPa以下胎压以及30℃时0.7MPa胎压作用500万次均不发生疲劳破坏;30℃时,1.1 MPa和1.38 MPa胎压分别作用66 833次和35 480次出现疲劳损坏现象;相同应变作用下,试验温度越低,小梁疲劳破坏越快;环氧沥青混合料疲劳曲线可明显分为试验设备稳定、疲劳裂缝启裂、疲劳裂缝扩展3个阶段。研究结果可为环氧沥青混合料铺装疲劳寿命预估以及预防性养护提供理论依据。
In order to obtain the fatigue degradation characteristics of epoxy asphalt mixture for steel bridge deck pavement, firstly, the standard tire pressure, overload 50% and overloading 100% tire pressure were calculated based on the composite structure model consisting of orthotropic bridge deck - pavement The maximum tensile strain of the underfloor layer is taken as the selection criterion for the strain level of the fatigue test; then the fatigue performance of the epoxy asphalt mixture under three different temperature and strain conditions is tested by using the four-point bending fatigue test of the beam; finally , The Weibull formula was used to predict the fatigue life and fatigue crack propagation times of epoxy asphalt mixture under different temperature and strain conditions. The results show that the initial modulus of epoxy asphalt mixture is only related to temperature and has nothing to do with the strain level. At 10 ℃ and 20 ℃, the tire pressure less than 1.38 MPa and the tire pressure no more than 5 million at 0.7 MPa at 30 ℃ do not occur Fatigue damage; At 30 ℃, 1.1 MPa and 1.38 MPa tire pressure respectively 66 833 times and 35 480 times appear fatigue damage phenomenon; under the same strain, the lower the test temperature, the faster the fatigue damage of the trabecular; Epoxy Asphalt Mixture The fatigue curve can be obviously divided into three stages of stable test equipment, fatigue crack initiation, and fatigue crack propagation. The results can provide a theoretical basis for the prediction of fatigue life and preventive maintenance of epoxy asphalt mixture pavement.