FWD荷载作用下碾压混凝土基层沥青路面的动态响应试验

Dynamic response experiment of roller compacted concrete base asphalt pavement under FWD load

为研究碾压混凝土基层沥青路面在落锤式弯沉仪(falling weight deflectometer,FWD)荷载作用下的动态响应,铺筑了试验路,通过在试验路内部布设应变传感器,获取了不同工况条件下试验路路面结构层内的应变响应,分析了碾压混凝土基层沥青路面的动态特性及荷载、温度等因素对路面动态响应的影响,构建了碾压混凝土基层沥青路面结构沥青面层底最大水平拉应变预估模型.结果表明:FWD荷载作用下,在距离荷载板中心30 cm范围内路表弯沉变化较大,距离荷载板中心30 cm范围以外,路表弯沉随位置变化的幅度较小,且温度越高,这种趋势越明显;在加载中心点的正下方,路面结构层内部表现为拉应变,且荷载越大,应变越大;相同荷载作用下,碾压混凝土基层沥青路面的底基层、基层与面层底的应变均小于传统半刚性基层沥青路面,随着荷载水平增加及温度升高,路面结构层内部的应变逐渐增大;路面结构层底的应变随荷载增加呈线性增加,随温度升高呈指数增加,路面温度升高50%,50 kN荷载作用下沥青面层底的应变水平与100 kN荷载相当.

To investigate the dynamic response of roller compacted concrete base(RCC-base)asphalt pavement under the load of falling weight deflectometer(FWD),a test road was paved.Laying strain sensors inside the test road,the strain responses in the pavement structure layer of the test road under different work conditions were obtained.The dynamic characteristics of RCC-base asphalt pavement and the effects of load and temperature on the dynamic response of pavement were analyzed.The prediction model of the maximum horizontal tensile strain at the bottom of RCC-base asphalt pavement was established.The results show that under the FWD load,the deflection of pavement surface varies greatly within the range of 30 cm from the center of load plate,and the deflection of pavement surface varies slightly with the location outside 30 cm from the center of load plate.The higher the temperature is,the more obvious the trend is.Under the load center,the bottom of pavement structure layer shows tension strain,and the greater the load is,the greater the strain value is.Under the same load,the strains of subbase,base and surface of RCC-base asphalt pavement are less than those of traditional semi-rigid base asphalt pavement.With the increasing of load level and temperature,the strain of pavement structure layer is increased gradually.The strain at the bottom of asphalt pavement structure is increased linearly with the increasing of load and exponentially with the increasing of temperature.When the pavement temperature is increased by 50%,the strain level of RCC-base asphalt pavement under 50 kN load is equivalent to that under 100 kN load.