多孔排水沥青混合料细观空隙结构研究

Study on Mesoscopic Void Structure of Porous Drainage Asphalt Mixture

多孔沥青混合料作为一种新型的功能路面材料,内部富有复杂且相互连通空隙结构,使得PAM具有排水、降噪和抗滑等优异性能,被广泛应用于高速公路和城市道路。通过梳理近年来国内外多孔沥青混合料研究现状和发展动态,发现多孔沥青混合料的内部空隙结构是影响其性能的重要因素,传统的宏观空隙测试方法得到的数据变异系数较大,无法解释实际工程中出现的一系列深层问题,而细观研究方法可从多角度量化空隙结构,进而明晰空隙结构对混合料性能的影响机理。为此,基于细观角度对PAM空隙结构研究进行总结。介绍了目前3种常用于获取PAM细观空隙结构信息的技术方法,对各个方法的优缺点进行了评述;重点梳理了近年来学者关于空隙特征指标的评价,并对PAM细观空隙结构未来研究方向进行展望。结果表明:PAM细观空隙结构分布特性的研究主要是基于图像处理、X-ray CT扫描及数值模拟等技术在工程领域创新型的应用,通过直观的视角对PAM混合料内部空隙结构进行深入研究,从细观方面极大丰富了空隙结构的研究内容;基于细观研究技术,有效空隙率、空隙等效直径、比表面积、空隙弯曲度等一系列空隙特征指标的相继提出,为进一步研究空隙结构与其渗透、降噪等性能之间的复杂关系提供了新思路。

As a new type of functional pavement material,PAM has a complex and interconnected void structure inside,which makes PAM have excellent performance such as drainage,denoising,and skid resistance,etc.It is widely used in highways and urban roads.By summarizing the research status and development of porous asphalt mixtures at home and abroad in recent years,it is found that the internal void structure of porous asphalt mixture is an important factor affecting its performance.The data variation coefficient obtained by the traditional macroscopic void test method is relatively large,which cannot explain a series of deep-seated problems in actual engineering.The mesoscopic research method can quantify the void structure from multiple perspectives,and then clarify the influence mechanism of the void structure on the mixture performance.For this reason,the research progress of PAM void structure is reviewed based on the meso-level perspective.Three technical methods which are commonly used to obtain PAM mesoscopic void structure information are introduced,and the advantages and disadvantages of each method are reviewed.At the same time,the evaluations of void characteristic indicators by scholars in recent years are emphatically sorted out,and the future research direction of mesoscopic void structure of PAM is prospected.The analysis result shows that(1)the researches on the distribution characteristics of PAM mesoscopic void structure are mainly based on the innovative application of image processing,X-ray CT scanning and numerical simulation in the engineering field,the internal void structure of PAM mixture is deeply studied from intuitive perspective,which greatly enriched the research content of void structure from the meso aspect;(2)based on the mesoscopic research technology,a series of void characteristic indicators such as effective air voids,void equivalent diameter,specific surface area,and void curvature are put forward one after another,which provides a new idea for further studying the complex relationship of void structure with its permeability,denoising and other properties.