细观结构灌浆沥青混凝土导热系数研究

Study on thermal conductivity of grouting asphalt concrete based on meso-structure

路面的导热系数和传热效率影响着城市热岛效应和冬季路面凝冰现象的发生。为从细观结构的角度研究灌浆沥青混凝土导热系数的影响因素,通过离散元软件PFC 3D生成灌浆沥青混凝土的细观模型,在COMSOL Multiphysics中对导热系数进行模拟,并进行理论计算。在实验室内进行灌浆混凝土的导热系数试验,相对误差为6.42%,验证细观模型模拟的准确性。通过验证的模型,分析不同空隙率和沥青混凝土骨架、水泥砂浆导热系数变化对灌浆沥青混凝土导热系数的影响。结果表明:空隙率在20%~28%之间,灌浆沥青混凝土导热系数与空隙率的改变近似呈线性变化,空隙率每增加2%,导热系数降低约3.1%;灌浆沥青混凝土导热系数随水泥砂浆和沥青混凝土骨架导热系数的增大而增大,但随着水泥砂浆和骨架导热系数值的不断增大,灌浆沥青混凝土的导热系数增长幅度越来越慢。

The thermal conductivity and heat transfer efficiency of pavement affect the urban heat island effect and the occurrence of pavement freezing in winter.In order to study the influencing factors of thermal conductivity of grouting asphalt concrete from the perspective of meso-structure,the meso-model of grouting asphalt concrete was generated by discrete element software PFC 3D.Then the thermal conductivity was simulated in COMSOL Multiphysics and the theoretical calculation was carried out.The thermal conductivity test of grouting concrete was carried out in the laboratory,and the relative error was 6.42%,which verified the accuracy of the mesoscopic model simulation.Through the verified model,the influence of different porosity and thermal conductivity of asphalt concrete skeleton and cement mortar on the thermal conductivity of grouting asphalt concrete was analyzed.The results show that when the porosity is between 20%and 28%,the thermal conductivity of grouted asphalt concrete changes approximately linearly with the change of porosity.For every 2%increase in porosity,the thermal conductivity decreases by about 3.1%.The thermal conductivity of grouting asphalt concrete increases with the increase of thermal conductivity of cement mortar and asphalt concrete skeleton,but with the increase of thermal conductivity of cement mortar and skeleton,the thermal conductivity of grouting asphalt concrete increases more and more slowly.