基于温度与荷载实际耦合的沥青路面车辙预估

Rutting prediction of asphalt pavement based on actual coupling of temperature and load

为了研究在路面温度场与实际交通荷载分布下的车辙发展规律,分析温度与荷载实际耦合作用对沥青路面车辙的影响,建立不同月份下的车辙预估公式,并通过室内试验分析温度对不同类型沥青混合料的车辙影响程度。利用ABAQUS有限元软件,建立了路面结构不同时间与深度处的温度场,同时考虑交通荷载随时间分布的特性,计算得到1d内不同时段轴载累积作用次数及时间分布比例,以确定各温度场下典型月份的车辙临界温度及年车辙临界温度。根据车辙与平均气温的关系式计算得到各月份平均温度与20℃平均温度下的车辙比,进行公式修正及换算后,得到不同月份下考虑路面温度与荷载实际耦合作用的车辙预估公式。研究结果表明:利用马歇尔方法得到沥青混合料动稳定度在60℃时突降,降低率高达50%,旋转试验机方法(GTM)得到的沥青混合料动稳定度最大降低率出现在70℃时,约为50%,高温对车辙的影响较大;12月、4月、8月份的车辙临界温度分别为16℃、22℃、33℃,路面的年车辙临界温度为30℃,且当路面温度低于临界温度时产生的车辙对总车辙的贡献率分别为10%、3.3%、1.5%;车辙RD与平均气温T的相关关系式为RD=0.122T2-3.344T+24.888,以及平均温度为20℃时的车辙RD20与荷载作用次数N的拟合公式为RD20=0.485 6 N0.188 9。

To analyze rutting development on an asphalt pavement,under the distribution of pavement temperature field,the actual traffic load,and the coupling effect of temperature and load,the rutting prediction formula across different months was established.The influence of temperature on the rutting of different types of asphalt mixtures was analyzed through an indoor test.ABAQUS was used to establish the temperature field at different time durations and depth of the pavement structure.According to the characteristics of traffic load distribution over time,the cumulative action time and time distribution ratio of axle load,during different periods in a day,were calculated.The critical rutting temperature and annual rutting temperature in typical months under each temperature field were determined.According to the relationship between therut and the average temperature,the rut ratio of the average temperature across different months and the average temperature at 20 ℃ was calculated.After correction and conversion of the formula,the rut prediction formula,considering the actual coupling effect of pavement temperature and load during different months,was obtained.The results show that the dynamic stability of the asphalt mixture decreases abruptly at 60℃ by Marshall method,with a reduction rate of 50%.The maximum rate of reduction of the dynamic stability of the asphalt mixture,obtained by rotating test machine（GTM）method,is about 50%,which occurs at 70 ℃.High temperature has a great influence on rutting.The rutting stagnation temperature in December,April and August are 16 ℃,22 ℃,and 33 ℃ respectively.The annual rutting stagnation temperature of the pavement is 30 ℃.The contribution of rutting to the total rutting is 10%,3.3% and 1.5% respectively,when the pavement temperature is lower than the stagnation temperature.The correlation formula between rutting RD and average temperature Tis RD =0.122 T2-3.344 T＋24.888,and the fitting formula between rutting RD20 and loading time Nat average temperature is RD20=0.4856 N0.188 9.