Abstract: In order to explore the influence mechanism of porous asphalt mixture structure on heavy metal removal from road surface runoff, the microscopic parameters, including equivalent diameter, number of voids, surface voidage, unit specific surface area and fractal dimension, were chosen as characteristic parameters. An indoor artificial rainfall test was implemented to study the influence mechanism of mesoscopic void characteristics on Pb2+ removal from porous asphalt surface by two kinds of target void fraction. Results show that surface voidage, unit specific surface area, void volume and fractal dimension have a positive correlation with the ability of porous asphalt mixture to remove Pb2+, that is, the bigger the parameter is, the better the Pb2+ removal effect is. The equivalent diameter has a negative correlation with the ability of porous asphalt mixture to remove Pb2+, that is, the bigger the parameter is, the worse the Pb2+ removal effect is. And the number of voids has no significant effect on Pb2+ removal from asphalt mixtures.

Key words: highway engineering, permeable asphalt pavement, microscopic void characteristics, road runoff, Pb2+

摘要： 为探究多孔沥青混合料空隙结构特性对透水沥青路面去除路面径流重金属的影响机制，于细观尺度下，选用等效直径、空隙数量、面空隙率、单位比表面积和分形维数作为特征参数； 采用室内人工模拟降雨试验，研究两种目标空隙率下，细观空隙特征对透水沥青面层去除径流中Pb2+的影响机制。结果表明：面空隙率、比表面积、空隙体积、分形维数与多孔沥青混合料去 除Pb2+的能力呈正相关关系，参数值越大、混合料对Pb2+的去除效果越好；等效直径与混合料去除Pb2+的能力呈负相关关系，参数值越大、混合料对Pb2+的去除效果越差；空隙数量则对沥青 混合料去除Pb2+的效果无显著影响。

关键词: 道路工程, 透水沥青路面, 细观空隙特征, 路面径流, 铅离子