高温重载下泡沫沥青冷再生路面响应分析

Dynamic Response Analysis of Foamed Asphalt Cold Recycled Pavement under High Temperature and Heavy Load

为解决高温与重载作用下泡沫沥青冷再生路面易产生车辙病害等问题,了解再生混合料分别作为下面层与上基层路面时的动力响应,设计一种高抗剪密实型泡沫沥青冷再生混合料(F-B),结合区域气候特点以及黏弹性理论,通过有限单元法获得了不同结构层的温度场与移动轴载下的应变变化,并与常规级配进行对比。结果表明:路面温度场具有明显的非线性特征,可通过改进级配的方式提高材料的抗剪切性能;卸载后路面存在约10%的残余应变,而采用黏弹性模型能够获得路面的残余变形,更好地反映车辙的形成;泡沫沥青层层底纵向应变呈现正负交替特点,易引发路面疲劳损伤;低速重载下,采用高抗剪密实型级配可以减少面层的最大剪应力,减少流动型车辙的产生;泡沫沥青作为下面层使用时,重载作用下路面具有更好的抗竖向变形能力。

In order to solve the problem of rutting on the cold recycled foamed asphalt pavement under the action of high temperature and heavy load,and to understand the dynamic response of the road surface when the recycled mixture was used as the lower layer and the upper base layer respectively,a high-shear and dense foamed asphalt cold recycling mixture(F-B)was designed,combined with regional climate characteristics and viscoelastic theory,obtained the temperature field of different structural layers and the strain changes under moving axle load through the finite element method,and compared with the conventional gradation.The results showed that the pavement temperature field had obvious non-linear characteristics,and the shear resistance of the material could be improved by improving the gradation.There was about 10%residual strain of the pavement after unloading,and the viscoelastic model could obtain the residual deformation of the pavement,which could better reflect the formation of ruts.The longitudinal strain of the foamed asphalt layer was alternating between positive and negative,which was easy to cause road fatigue damage.Under low speed and heavy load,the use of high shear density grading could reduce the maximum shear stress of the surface layer and the generation of flow rutting.When foamed asphalt was used as the lower layer,the road surface had better resistance to vertical deformation under heavy load.