集料均匀性对沥青混合料力学性能影响的离散元模拟

发布时间：2018-05-15 18:13

本文选题：沥青混合料 + 均匀性　；参考：《浙江大学》2014年硕士论文

【摘要】：沥青混合料均匀性是沥青路面早期破坏最主要的原因,决定着沥青路面的力学性能和使用寿命。沥青混合料属多相颗粒复合材料,物理力学性能十分复杂,常规室内实验与有限元等连续介质力学理论很难从本质上揭示其复杂的力学机理。本文基于数字图像处理技术,从颗粒流离散元角度探究沥青混合料均匀性对其不同力学性能的影响。首先基于数字图像处理技术,编写了实际边界、多边形和椭圆等三种集料形状的PFC接口程序,建立了沥青混合料水平向与竖向截面的二维离散元模型。其次模拟沥青混合料低温劈裂性能,分析了集料破碎性、空隙和集料几何形状对劈裂性能的影响；基于时温等效原理建立了Burgers粘弹性离散元模型,模拟沥青混合料高温条件下单轴压缩和单轴贯入试验的力学性能,分析加载速率、粘弹性参数等的敏感性；探究了不同沥青混合料级配下集料分布状态对劈裂、单轴压缩以及贯入试验等力学性能的影响,且分别进行了上述各类虚拟数值试验对应的室内实验,验证沥青混合料均匀性对其力学性能的影响。最后基于离散元伺服原理模拟了沥青混合料单轴静态蠕变的路用性能,并探究了不同级配下集料均匀性对蠕变路用性能的影响。研究结果表明,集料几何形状、空隙、粘弹性参数、加载速率等对沥青混合料力学性能均有显著影响。基于集料分布状态,沥青混合料的均匀性与其高低温力学性能的变异系数有很好的相关性,且级配和最大公称粒径对均匀性的影响很显著。
[Abstract]:The uniformity of asphalt mixture is the main reason for the early failure of asphalt pavement, which determines the mechanical properties and service life of asphalt pavement. Asphalt mixture is a kind of multiphase particle composite material, and its physical and mechanical properties are very complex. It is difficult to reveal its complicated mechanics mechanism in nature by conventional laboratory experiments and finite element theory of continuum mechanics. Based on digital image processing technology, this paper explores the influence of asphalt mixture uniformity on its different mechanical properties from the point of particle flow discrete element. Firstly, based on the digital image processing technology, the PFC interface program of actual boundary, polygon and ellipse is written, and the two-dimensional discrete element model of horizontal and vertical sections of asphalt mixture is established. Secondly, the low temperature splitting performance of asphalt mixture is simulated, and the effects of aggregate fragmentation, void and aggregate geometry on the splitting performance are analyzed. Based on the principle of time-temperature equivalence, the Burgers viscoelastic discrete element model is established. The mechanical properties of order axial compression and uniaxial penetration tests were simulated under high temperature conditions of asphalt mixture, and the sensitivity of loading rate and viscoelastic parameters were analyzed, and the effect of aggregate distribution state on splitting under different asphalt mixture gradation was investigated. The effects of uniaxial compression and penetration test on mechanical properties were investigated and the laboratory experiments were carried out respectively to verify the effect of asphalt mixture uniformity on its mechanical properties. Finally, the pavement performance of asphalt mixture under uniaxial static creep is simulated on the basis of discrete element servo principle, and the influence of aggregate uniformity on creep pavement performance under different gradation is explored. The results show that the geometry of aggregate, void, viscoelastic parameters and loading rate have significant effects on the mechanical properties of asphalt mixture. Based on the aggregate distribution state, the uniformity of asphalt mixture has a good correlation with the coefficient of variation of its mechanical properties at high and low temperatures, and the influence of gradation and maximum nominal particle size on the uniformity is very significant.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U414

【参考文献】