Study on meso-structural characteristics and homogeneity of asphalt mixture skeleton contacts

Asphalt mixture skeleton is the main structure to resist load, and the contact point between coarse aggregates is one of the key elements of skeleton structure. This study investigated the difference in key aggregate particle size on the meso-contact characteristic and the distribution homogeneous of contact points. In addition, the relationship between the evaluation parameters of skeleton homogeneity and the macro-rutting resistance of asphalt mixtures was examined. Finally, various measures were proposed to improve the skeleton contact distribution homogeneity. The results indicated that the minimum calculated particle size significantly influenced the contact between coarse aggregates. The contact changes between coarse aggregates include increasing contacts, disappearing contacts, and changing contact positions. Measures to improve the contact distribution homogeneity of asphalt mixtures include increasing the compaction time, increasing the coarse aggregate content, and decreasing the key particle size. When the minimum calculated particle size was set to 2.36 mm, the anti-rutting parameters correlated with the statistical parameters of the coarse aggregate contact distribution. However, there was no good correlation between them when the minimum calculated particle size was 4.75 mm. These results suggest that when calculating the skeleton contact, the particle size of 2.36 mm is more reasonable to effectively characterize the mesostructure of the asphalt mixture skeleton.