沥青路面冷再生试验路车辙变形的时空分布

Spatio-temporal Distribution of Rutting Deformation of Cold Recycled Test Road with Asphalt Pavement

为了揭示冷再生沥青混合料在结构中的力学行为,为道路维修养护中的结构设计提供依据,研究依托山东省某高速公路试验路的冷再生沥青路面结构及其中传感器监测数据,分析冷再生结构层在行车荷载作用下的动态响应特点及规律。依托实测温度场数据,构建黏弹性有限元仿真模型,分析了冷再生沥青路面结构车辙的分布规律。结果表明:对于试验路结构的冷再生沥青混合料层,行车速度与结构内部应变响应持续时间呈幂函数关系,在60~80 km/h的速度下,其结构层内部的力学响应频率接近10 Hz;在路面设计时,冷再生层可取其在20℃、10 Hz下的动态模量作为结构模量;对于冷再生沥青试验路结构,其一天中逐小时车辙量的分布主要与交通量相关,一年中的月车辙量的分布主要与温度相关,其中,一年之内的车辙累积主要发生在5—10月,冬季期内发生的车辙量几乎可以忽略不计;为避免由于结构层厚度增加导致过高的车辙预估量,需在计算沥青混合料层永久变形等效温度时对沥青层的厚度进行限制;此外,在高温条件下,相较于动态模量的改变,控制上、中面层沥青混合料在40~45℃左右的塑性变形发展速率对于减小路面永久变形的累积具有更为显著的作用。

In order to reveal the mechanical behavior of cold recycled asphalt mixture in the structure and provide a reference for structural design in road maintenance,relying on the cold recycled asphalt pavement structure and field sensor monitoring data from an expressway test road in Shandong province,the dynamic response characteristics of cold recycled asphalt pavement under traffic load are analyzed.Based on the measured temperature field data,a viscoelastic finite element simulation model is constructed to analyze the rutting distribution of cold recycled asphalt pavement structures.The result shows that for the cold recycled asphalt mixture layer of the test road structure,the driving speed has a power function relationship with the duration of the internal strain response of structure.At the speed of 60-80 km/h,the mechanical response frequency inside the structural layer is close to 10 Hz.In pavement design,the dynamic modulus of the cold recycled mixture at 20℃and 10 Hz can be adopted as the structural modulus.The distribution of hourly rutting volume in a day is mainly related to traffic volume in the cold recycled asphalt test road structure.The distribution of monthly rutting volume in a year is mainly related to temperature,the rutting accumulation within a year mainly occurs from May to October,and the rutting amount in winter can be almost negligible.In order to avoid excessive rutting predictions due to increased layer thickness,the thickness of asphalt layer needs to be limited when calculating the equivalent temperature for permanent deformation of the asphalt mixture layer.In addition,compared with the change of dynamic modulus at high temperature,controlling the plastic deformation development rate of the asphalt mixture in the upper and middle surface at about 40-45℃shows a more significant effect in reducing the accumulation of pavement permanent deformation.