Delaunay三角网格的沥青混合料粗集料分布特性

为研究沥青混合料的细微观结构特征,提出粗集料分布特性的量化方法和指标.基于数字图像处理技术对粒径大于2.36 mm的沥青混合料粗集料质心进行delaunay三角剖分,建立三角单元内A1/A2（集料-胶浆面积比）参数表征细观结构局域特征,通过对A1/A2统计特性的描述、分析以及概率形式的统计推断,得到粗集料整体分布特性的量化与分析结果.研究表明,不同级配之间粗集料的总量及级配各档位质量分布的差异性将显著影响细观结构特征,如沥青玛蹄脂碎石混合料（SMA）、开级配抗滑磨耗层混合料（OGFC）和高性能路面沥青混合料（SUP） 3种级配粗集料的平均紧密程度呈递减趋势.此外,给出A1/A2参数的集中趋势指标和偏态指标,并在此基础上提出非参数检验方法对沥青混合料细观结构进行对比,评判多种级配细观结构的嵌挤紧密特征的异同,认为SMA和OGFC的细观嵌挤特征类似,而SUP和SMA以及OGFC相比细观结构更趋于分散.

Analysis of distribution properties of coarse aggregates in HMA based on delaunay triangulation

To investigate the microstructure of asphalt concrete,a new method was proposed to analyze the distribution properties of coarse aggregates.Based on the digital image processing and computational geometry,delaunay triangulation method was used to generate the centroid of the coarse aggregates which square sieve size larger than 2.36mm.Then,coarse aggregate-asphalt bind area ratio(A1/A2) for each delaunay triangle was calculated by statistics theory.The A1/A2 varies with different gradations,therefore,it can be used to represent the local character of the hot mixture asphalt(HMA) microstructure.According to the statistic analysis,it indicates that the total mass and each graded mass of the coarse aggregates both significantly influence the microstructural character of HMA.The central tendency and skewness of A1/A2 is helpful to judge the dense degree of the coarse aggregate skeleton,and the nonparametric tests can further provide the possibility of classifying the microstructure of the HMA.By comparing three different gradations,such as stone matrix asphalt(SMA),open graded friction course(OGFC),and superpave(SUP),it shows SMA has the largest dense degree of coarse aggregates distribution,and SUP appears the least dense degree characteristic.Furthermore,SMA and OGFC have similar type of microstructure while SUP’s type is different from others.