基于分形理论的沥青混合料导热系数研究

Research on Thermal Conductivity of HMA Based on Fractal Theory

沥青混合料的导热系数是沥青路面温度场研究的重要参数。简要介绍了级配分形维数的定义和计算方法,计算了所选用级配的分形维数。根据瞬变平面热源法,采用Hot disk导热系数测试仪,测试了各级配在不同沥青用量时的导热系数。根据试验结果,分析了导热系数的影响因素,分别建立了沥青混合料的导热系数与空隙率和级配分形维数的回归关系。空隙率越大,材料的导热系数越小;在用油量相同的情况下,级配的分形维数越大,材料的导热系数越大。分形维数与导热系数之间的相关性较好,可以用来表征级配对材料导热系数的影响。

The thermal conductivity of the HMA is an important parameter in the research of the temperature field.The definition and calculation of fractal dimension are introduced briefly.The fractal dimension of the gradations chosen is calculated.Based on the transient plane source method,using Hot disk thermal conductivity analyzer test the thermal conductivity of different types of HMA with different asphalt dosages.According to the results,the influence factors of the thermal conductivity are discussed.The relations among thermal conductivity,void percentage and fractal dimension are built.Thermal conductivity decreases with the increase of void percentage.Thermal conductivity increases with the increase of fractal dimensions.Because of the good relativity between fractal dimension and thermal conductivity,fractal dimension can be used to show the influence of gradations.