基于RIOHTrack足尺环道全寿命周期试验的沥青路面车辙变形长期演化行为

Long-term Evolution Behavior of Rutting Deformation on Asphalt Pavement Based on RIOHTrack Full-scale Loop Life-cycle Test

为获取符合全寿命周期要求的千万次以上荷载水平下的车辙演化过程,依托足尺路面加速加载试验环道RIOHTrack,开展了沥青路面全寿命周期加速加载试验,获取了沥青路面长期服役过程中的车辙变形演化数据,覆盖了19种沥青路面结构在8000万累计标准轴次下的车辙试验结果,据此研究了沥青路面全寿命周期内车辙变形的长期演化行为规律和作用机理。研究结果表明:在全寿命周期内,沥青路面车辙损伤演化呈现出以年为周期的增大-减小-增大的波动性增长现象;不同路面结构的车辙变形存在较大差异,基层强度越高则车辙越小,减小幅度在8%~18%之间;单位厚度的车辙深度与沥青混凝土层厚度之间存在良好的指数函数关系,薄沥青面层结构上面层的车辙贡献率可达到80%,随着沥青层厚度的增加,中、下面层的车辙贡献率逐渐增加;直线路段的车辙明显大于缓和曲线段,后者的受力模式更接近于水平推移变形;可采用三次曲线模型描述全寿命周期内车辙演化过程,模型存在2处拐点,拐点过后车辙演化进入新的发展阶段。根据车辙演化模型,可以预估不同车辙设计要求值时所对应的累计标准轴次,可作为以车辙为指标的寿命预估。

To obtain rutting evolution data under tens of millions of load levels that meet the requirements of the whole life cycle based on the full-scale pavement accelerated loading-test ring RIOHTrack,the accelerated loading test of the whole life cycle of asphalt pavement was performed,and the rutting deformation evolution data during the long-term service of asphalt pavement was obtained.Based on the rutting test results of 19 asphalt pavement structures under 80 million equivalent single axle loads,the long-term evolution behavior and mechanism of rutting deformation in the whole life cycle of asphalt pavement are investigated.Results showed that the rutting damage evolution of asphalt pavement exhibited an increase-decrease-increase fluctuation in the whole life cycle of asphalt pavement.The rutting deformation differs with pavement structures.The higher the base strength,the smaller the rutting,and the reduction range was between 8%and 18%.A good exponential relationship between rutting depth per unit thickness and asphalt concrete-layer thickness was observed.The rutting contribution rate of the thin asphalt surface layer reached 80%.With the increase of asphalt layer thickness,the rutting contribution rate of the middle and lower layers increased gradually.The rutting of the straight section was greater than that of the gentle curve section,and the stress mode of the latter was closer to the horizontal deformation.A cubic-curve model can be used to describe the rutting evolution process in the whole life cycle.There are two inflection points in the model,after which the rutting evolution enters a new development stage.According to the rutting evolution model,the cumulative axles corresponding to different rutting design requirements can be estimated,which can be used as the life prediction based on rutting.