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为了研究柔性基层沥青混凝土路面结构在使用寿命周期内的衰变规律,铺筑了4种级配碎石基层足尺APT试验路,埋设了由沥青应变仪、压应力传感器等组成的力学响应实时监测系统和温湿度环境参数观测系统。通过对APT试验路进行加速加载疲劳破坏试验,实时监测路面力学响应随荷载作用次数和路面温度的变化;跟踪进行了16次贝克曼梁弯沉测试和5次FWD弯沉测试,研究了沥青混凝土层层底动应变响应衰变规律,提出了沥青混凝土层发生疲劳开裂的判断依据和技术手段。研究结果表明:温度升高,沥青混凝土层层底水平拉应变值增大,温度降低则应变值减小;沥青混凝土层未发生疲劳开裂时,路面温度与沥青混凝土层层底最大拉应变随轮载作用次数的变化规律完全一致;沥青混凝土层层底出现疲劳开裂后,两者随荷载作用次数关系曲线发生背离。沥青混凝土层底最大拉应变与温度随轮载作用次数的变化规律可作为沥青混凝土层发生疲劳开裂的判断依据;源自于路表自顶向下发展的裂缝对沥青混凝土层层底动力响应没有影响。
In order to study the decay law of the asphalt pavement structure with flexible base during its service life, four types of APT test road with graded gravel base were paved. The mechanical response real-time monitoring including asphalt strain gauge and compressive stress sensor System and temperature and humidity environment parameter observation system. Through the APT test road accelerated loading fatigue failure test, real-time monitoring of road mechanics response with the load of the number of times and the change of road surface temperature; Followed by 16 Bekman beam deflection test and 5 FWD deflection test, the study of asphalt concrete Based on the law of the bottom soil dynamic strain response decay, the judgment basis and technical means of asphalt concrete layer fatigue cracking were proposed. The results show that when the temperature rises, the horizontal tensile strain at the bottom of asphalt concrete layer increases and the strain decreases when the temperature decreases. When the asphalt concrete layer is not undergoing fatigue cracking, the maximum tensile strain at the bottom of the asphalt concrete layer varies with the wheel The variation law of loading times is exactly the same. When the fatigue cracks occur in the bottom of asphalt concrete layer, the two curves deviate from the curves of load times. Asphalt concrete layer at the end of asphalt concrete layer maximum tensile strain and temperature changes with the law of the number of changes can be used as asphalt concrete layer fatigue crack initiation judgment; derived from the top-down development of the road surface crack on the asphalt concrete bottom dynamic response is not influences.