Wang Sudi, Wang Jianxia, Wang Jie, Xu Jian, Miao Yinghao, Ma Qing, Wang Linbing, Liu Tao
Research Institute of Highway Ministry of Transport, Beijing 100088, China.
Jiangxi Transportation Investment Group Co., Ltd., Nanchang 330025, China.
Materials (Basel). 2025 May 18;18(10):2347. doi: 10.3390/ma18102347.
The force chain network within asphalt mixtures serves as the primary load-bearing structure to resist external forces. The objective of this study is to quantitatively characterize the contact force distribution and force chain topology structure. The discrete element method (DEM) was employed to construct simulation models for two stone matrix asphalt (SMA) and two open-graded friction course (OGFC) mixtures. Load distribution characteristics, including average contact force, load bearing contribution and contact force angle, and force chain topological network parameters, clustering coefficient, edge betweenness and average path length, were analyzed to elucidate the load transfer mechanisms. The findings of the present study demonstrate that the average contact force between aggregate-aggregate contact types in specific particle sizes significantly exceeds the average contact force of the same particle size aggregates. For SMA16 and OGFC16 asphalt mixtures, the load-bearing contribution of aggregates initially increases and then decreases with decreasing particle size, peaking at 13.2 mm. SMA13 and OGFC13 mixtures demonstrate a consistent decline in load bearing contribution with decreasing aggregate size. The analysis of the force chain network topology of the asphalt mixture reveals that SMA mixtures exhibited higher average clustering coefficients in force chain topological features in comparison to OGFC mixtures. It indicates that SMA gradations have superior skeletal load-bearing structures. While the maximum nominal aggregate size minimally influences the average path length with a relative change rate of 3%, the gradation type exerts a more substantial impact, exhibiting a relative change rate of 7% to 9%. These findings confirm that SMA mixtures have more stable load-bearing structures than OGFC mixtures. The proposed topological parameters effectively capture structural distinctions in force chain networks, offering insights for optimizing gradation design and enhancing mechanical performance.
沥青混合料内部的力链网络是抵抗外力的主要承载结构。本研究的目的是定量表征接触力分布和力链拓扑结构。采用离散元法（DEM）构建了两种沥青玛蹄脂碎石混合料（SMA）和两种开级配磨耗层混合料（OGFC）的模拟模型。分析了包括平均接触力、承载贡献和接触力角度在内的荷载分布特征以及力链拓扑网络参数、聚类系数、边介数和平均路径长度，以阐明荷载传递机制。本研究结果表明，特定粒径下集料-集料接触类型之间的平均接触力显著超过相同粒径集料的平均接触力。对于SMA16和OGFC16沥青混合料，集料的承载贡献最初随粒径减小而增加，然后减小，在13.2mm处达到峰值。SMA13和OGFC13混合料的承载贡献随集料尺寸减小而持续下降。对沥青混合料力链网络拓扑的分析表明，与OGFC混合料相比，SMA混合料在力链拓扑特征方面表现出更高的平均聚类系数。这表明SMA级配具有更优越的骨架承载结构。虽然最大公称粒径对平均路径长度的影响最小，相对变化率为3%，但级配类型的影响更大，相对变化率为7%至9%。这些发现证实，SMA混合料比OGFC混合料具有更稳定的承载结构。所提出的拓扑参数有效地捕捉了力链网络中的结构差异，为优化级配设计和提高力学性能提供了见解。
