基于足尺加速加载试验的现役沥青路面疲劳特性研究

Study on Fatigue Performance of In-service Asphalt Pavement Based on Full-scale Accelerated Loading Test

为了对现役沥青路面的疲劳性能进行评价,在上海的某在役高速公路上选取了3个加载区进行了足尺加速加载试验。加速加载试验过程中,对开裂现象进行了观测并采用地震波地质分析仪对沥青层的地震波模量进行了检测。检测结果表明,随着加速加载作用次数的增加,路面沥青层的地震波模量不断降低,沥青层的地震波模量与加速加载作用次数具有较好的指数函数关系。加速加载试验结束后,在各加载区和非加载区进行了取芯,并通过劈裂强度试验和劈裂疲劳试验对现场沥青混合料的劈裂强度和疲劳抗力进行了评价。劈裂疲劳试验结果表明,随着沥青混合料所经受加速加载作用次数的增加,沥青混合料的初始劲度模量和疲劳寿命总体上不断下降,且加速加载作用对上面层混合料疲劳抗力的影响相比中、下面层混合料更为显著。基于Miner法则对现役沥青混合料的剩余疲劳寿命进行了预估。

To evaluate the fatigue performance of in-service asphalt pavement,the full-scale accelerated loading test in 3 field test sections of a selected in-service expressway in Shanghai is carried out.During the accelerated loading testing,the cracking phenomenon is observed and the portable seismic property analyzer(PSPA)is used to measure the seismic modulus of asphalt layer.The test result shows that the seismic modulus of the asphalt layer decreased with the increasing of accelerated loading times,and there is a good exponential function relationship between seismic wave modulus of asphalt layer and accelerated loading times.Asphalt layer cores are taken from the loading sections and the sections without loading after the accelerated loading test.The splitting strength test and splitting fatigue test are carried out to evaluate the splitting strength and fatigue resistance of the in-situ asphalt mixtures.The test result shows that the initial stiffness modulus and fatigue life of the in-situ asphalt mixtures decreased on the whole with the increasing of accelerated loading times,and the accelerated loading made a more significant influence on the fatigue resistance of the upper surface mixture than those of the middle and lower surface mixture.The residual fatigue lives of in-service asphalt mixtures are estimated based on the Miner’s rule.