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为了弥补现有沥青路面结构设计理论中将沥青混合料当作完全弹性体进行计算分析的不足,以AC-16,AC-20,开级配大粒径沥青碎石混合料OLSM-25的劈裂强度为研究对象,采用离散元方法,运用二维颗粒流程序(PFC2D),从细观角度入手,对AC-16,AC-20,OLSM-25的劈裂(间接拉伸)试验进行数值模拟,对比分析AC-16,AC-20,OLSM-25圆柱体试件内部集料颗粒之间的接触力、位移矢量、微裂缝数量及其分布规律。结果表明:在峰值轴向力作用下,当沥青混合料圆柱体试件开裂破坏时,随着沥青混合料公称最大粒径、空隙率的增大以及油石比的减小,试件内部集料颗粒之间的接触力由基本均匀趋于相对离散分布,位移矢量存在显著差异,微裂缝数量逐渐减少。与AC-16,AC-20相比,OLSM-25的间接拉伸抗裂效果显著。
In order to make up for the insufficiency of calculation and analysis of asphalt mixture as a complete elastomer in the existing asphalt pavement structure design theory, using the split of AC-16, AC-20 and open graded large-size asphalt aggregate OLSM-25 The splitting (indirect tensile) test of AC-16, AC-20 and OLSM-25 was carried out by using the discrete element method and the two-dimensional particle flow program (PFC2D) The contact forces, displacement vectors, the number of micro-cracks and their distribution among the aggregate particles in the AC-16, AC-20 and OLSM-25 cylindrical specimens were simulated and compared. The results show that under the action of the peak axial force, when the specimens of asphalt mixture cylinder crack and rupture, with the increase of the nominal maximum particle size and porosity of the asphalt mixture and the decrease of the ratio of the whetstone, The contact force between the particles tends to be relatively discrete from the basic uniform distribution, the displacement vector has significant differences, and the number of micro-cracks decreases gradually. Compared with AC-16, AC-20, OLSM-25 indirect tensile crack-resistant effect is significant.