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为了研究关键因素对密级配沥青混凝土低温断裂性能的影响,采用离散单元法(DEM)和三维颗粒流程序PFC3D模拟弯曲断裂试验.基于随机生成算法和虚拟不规则粗集料库模拟集料级配和不规则形状、沥青砂浆以及空隙率的生成过程.然后,在虚拟试件中添加细观力学接触本构模型进行虚拟断裂试验,虚拟试验结果与室内试验结果对比验证了虚拟试验结果的有效性.此外,基于虚拟仿真采用正交试验研究集料和空隙的体积分数、集料和沥青砂浆的刚度、沥青砂浆内部粘结强度以及集料和空隙的分布对虚拟断裂试验的影响.研究表明,上述因素对断裂性能都有不同程度的影响,其中对弯拉强度和弯曲应变能密度影响最大的是沥青砂浆的粘结强度,对弯拉应变影响最大的是粗集料的体积分数.为了得到较好的密级配沥青混合料低温断裂性能,考虑沥青砂浆和集料的细观结构非常重要.
In order to study the influence of key factors on the low temperature rupture performance of HDPE, discrete element method (DEM) and three-dimensional particle flow program PFC3D were used to simulate the bending fracture test.Based on random generation algorithm and virtual irregular coarse aggregate library, And irregular shape, asphaltic mortar and void generation process.At the end of this paper, the meso-mechanics contact constitutive model was added to the virtual test specimen for virtual fracture test. The comparison between the virtual test result and the indoor test result shows the validity of the virtual test result .In addition, based on the virtual simulation, the orthogonal experiment was used to study the volume fraction of aggregates and voids, the stiffness of aggregate and asphalt mortar, the internal bond strength of asphalt mortar and the distribution of aggregates and voids on virtual fracture test. The above factors have different degrees of impact on the fracture properties, of which the most influential on the bending strength and bending strain energy density are the bond strength of asphalt mortar, the most influential on the bending strain is the volume fraction of coarse aggregate.In order to obtain Better dense graded asphalt mixture with low temperature fracture properties, considering the meso-structure of asphalt mortar and aggregates Important.