Meso-structural evaluation of asphalt mixture skeleton contact based on Voronoi diagram

The Voronoi diagram is a fundamental data structure for spatial neighborhood relations used in various fields related to geometric information. Taking four asphalt mixtures as the research object, this study established the skeleton contact Voronoi diagram model to characterize the contact meso-structure between coarse aggregates, and extracted the quantitative information of skeleton contact space. The results show that the skeleton contact Voronoi diagram model can represent important spatial information of asphalt mixtures from the meso-structure including the homogeneity of asphalt mixtures, the extrusion relationship between coarse and fine aggregates, and the skeleton contact distribution characteristics, etc. The shape of the connected tree reflects the coarse aggregate contact distribution and load transfer trend, and the order of the connected tree reflects the contact connectivity strength of the skeleton. We used Voronoi diagram area Vs, connected tree area TVs and the total length of contact points L to quantitatively evaluate the skeleton contact of asphalt mixtures. In the design of asphalt mixtures with dense skeletons, the evaluation criteria of skeleton contact characteristics include Vs (30–180 mm2) proportion ≥75 %, Tr-1 and Tr-2 proportion ≤75 % and L ≥70. The results provide new ideas to promote the quality of asphalt mixtures and pavement construction.