顾盛 陈满军 林莉 王炯月 马翔

摘 要：为研究排水性沥青混凝土在使用过程中的堵塞特性，采用自行开发的大空隙沥青混凝土渗透系数测试装置，研究2种不同堵塞方式对大空隙沥青混凝土渗透系数的影响，并通过CT扫描其内部细观空隙结构。研究表明：渗流方向的渗透系数受堵塞剂影响严重;堵塞剂质量相同时，堵塞物含量小的堵塞剂对大空隙沥青混合料的堵塞更严重;多次堵塞及一次性堵塞的试件，其竖向及横向扫描出的长轴与短轴值均小于基准试件;堵塞过程中空隙率的减小主要是大孔数量及大孔比在减小，在细料堵塞后，大孔逐渐演变为中孔，导致中孔比增加。堵塞物沿着渗流方向在空隙中的滞留导致排水性路面渗透系数减小、排水功能衰减。

关键词：大空隙沥青混合料;CT扫描;堵塞行为;细观空隙结构

中图分类号：TU528.42    文献标识码：A   文章编号：1006-8023（2021）03-0126-05

Abstract：In order to study the clogging characterization of the porous asphalt concrete during the service period， the influence of two different plugging methods on the permeability coefficient of largevoid asphalt concrete was studied by using the selfdeveloped largevoid asphalt concrete permeability coefficient test device， and CT scanning was used to study the mesoscopic void structure of the plugged specimen. The results showed that the plugging agent mainly affected the permeability coefficient of the seepage direction. When the quality of the plugging agent was the same， the plugging agent with small plugging material content would be more serious to the large void asphalt mixture. For the specimens with multiple blockages and onetime blockage， the long axis and short axis values scanned vertically and horizontally were smaller than the reference specimen. The decrease of the void ratio during the blockage process was mainly due to the decrease in the number of large voids and the large void ratio. After the clogging of the fine material was added， the large void gradually evolved into medium void， resulting in an increase in the medium void ratio. The retention of the clogs in the void along the seepage direction lead to the decrease of the permeability coefficient and the attenuation of drainage function of the drainage pavement.

Keywords：Large void asphalt mixture; CT scanning; clogging behavior; mesoscopic void structure

0 引言

大空隙沥青混凝土的空隙率一般为18%～25%，由于其大空隙特性使其路面具有良好的表面功能，尤其是雨天减低路面积水，提高行车的安全性[1-2]。在实际使用过程中，随着空隙率受堵塞而衰减，大空隙沥青混凝土各向滲透行为均有不同程度的衰减[3]。马翔等[4]研究成果表明，降雨过程中悬浮颗粒的沉淀是排水路面空隙堵塞的主要原因，深截面堵塞比浅截面堵塞严重，沿着水流方向，越往外，空隙堵塞越严重。Deo等[5]认为细土、砂石及碎的有机材料是大空隙路面的主要堵塞物质。Chopra等[6]研究表明，透水路面的堵塞物以0.075 mm以下沙子含量最大。……