沥青混凝土试件集料特征细观力学分析

Micro-mechanical Analysis of Asphalt Concrete Specimen Aggregate Characteristics

为研究集料形状、级配和空间位置对沥青混凝土材料竖向变形的影响,依据AC-20沥青混凝土级配曲线和瓦拉文公式分别确定方形和圆形集料投放数目,随机投放集料并生成数值试件,通过室内试验获取材料参数后对数值试件进行数值仿真分析。结果表明:集料级配曲线中最大集料与数值试件尺寸比小于19/300时能达到较好的仿真精度;最大粒径集料的数目和空间位置对试件变形影响最大,但缺少某些档位的断级配集料曲线的试件变形性能优于连续级配曲线,断去中间级配对试件变形的影响不大;圆形集料对断级配的敏感性高于方形集料。研究表明,细观力学方法能较好地分析沥青混凝土的材料特性;集料的空间位置对数值试件竖向变形影响较大。

In order to study influences of shape, grading and spatial position of aggregates on vertical deformation of asphalt concrete materials, this paper determines the quantity of square and round aggregates put in according to grading curve of AC -20 asphalt concrete and Walraven formula, respectively, puts in aggregates randomly and generates numerical specimen, and carries out numerical simulation analysis for numerical specimen after acquisition of material parameters via indoor test. The results show that better simulation precision can be achieved when the size ratio of the largest aggregate in grading curve of aggregates to numerical specimen is less than 19/300 ; the quantity and spatial position of aggregates at the maximum particle size have the biggest influence on deformation of specimen, however, the deformation performance of specimen in interrupted grading aggregate curve in shortage of some gears is superior to continuous grading curve, the influence on deformation of specimen after intermediate grading is interrupted is not grate; the sensitivity of round aggregates to interrupted grading is higher than square aggregates. The study shows that the micro mechanical method can better analyze material properties of asphalt concrete; the spatial position of aggregates exhibits bigger influence on vertical deformation of numerical specimen.