粗集料接触参数对沥青混合料细观损伤机制影响研究

With the rapid growth of traffic and the severe circumstance of overload, the early diseases of asphalt pavement are noticeably increasing. Existing research on the material properties of asphalt pavement is mainly based on experimental tests and engineering experience, which is usually time-consuming and is unable to unveil the influence of coarse aggregate on the damage mechanism of asphalt mixture at meso-scale. Focusing on the contact parameters of coarse aggregate at mesoscopic level, its influence on the interfacial damage characteristic and fatigue failure mechanism of asphalt mixture is studied in this project. There are three main themes in the project. Firstly, based on the three-dimensional packing and filling theory and the particle interference theory, the judgment method of framework structured coarse aggregate and the contact parameters of coarse aggregate characterizing the stable state of framework structure are proposed respectively. Secondly, combining the digital image processing technique and the finite element method, a cohesive zone model reflecting the damage evolution of skeleton particles interface in asphalt mixture is built, and the law of the meso-damage state for interface in asphalt mixture is described. Finally, based on the combination of the four-point bending fatigue test and digital image correlation (DIC), the fatigue damage mechanism and the deformation distribution of asphalt mixtures are studied at mesoscopic scale with different contact parameters of coarse aggregate. The correlation between contact parameters of coarse aggregate and meso-damage of mixtures is examined by analyzing the rule of the fatigue damage quantitatively. This project aims to reveal the influence of the contact parameters of coarse aggregate on the meso-damage mechanism of asphalt mixture. Results of this project are supposed to help optimizing the mechanical properties of asphalt mixture and to decrease the early damage of asphalt pavement.

随着交通量增长、重载情况的加剧，沥青混凝土路面的早期破坏现象突出。目前，针对沥青路面材料性质的研究主要采用经验与试验相结合的研究方式，这种传统的研究方式费时费力，且很难通过宏观指标来揭示粗集料对骨架结构混合料内部细观损伤的影响规律。本项目利用粗集料接触参数为切入点，从细观层面出发，研究其对骨架结构沥青混合料的界面损伤特征及疲劳损伤机制的影响。具体内容包括：提出构成骨架的粗集料颗粒判定方法及用于表征骨架结构稳定状态的粗集料接触参数；将数字图像处理技术与有限元方法相结合，建立内聚力模型，描述不同粗集料接触参数影响下混合料界面细观损伤特征规律；采用四点弯曲疲劳试验与数字图像相关方法，分析不同粗集料接触参数的混合料细观变形分布特征以及其疲劳损伤破坏机理。本项目旨在揭示粗集料接触参数对沥青混合料的细观损伤机制的影响，以期由粗集料接触参数来优化混合料的力学性能，降低路面工程中的早期损害现象。

针对沥青路面材料性质的研究主要采用经验与试验相结合的研究方式，这种传统的研究方式费时费力，且很难通过宏观指标来揭示粗集料对骨架结构混合料内部细观损伤的影响规律。本项目利用粗集料接触参数为切入点，从细观层面出发，研究了其对骨架结构沥青混合料的界面损伤特征及疲劳损伤机制的影响。具体内容包括：提出了构成骨架的粗集料颗粒判定方法及用于表征骨架结构稳定状态的粗集料接触参数；将数字图像处理技术与有限元方法相结合，建立了多尺度沥青混合料内聚力模型，描述了不同粗集料接触参数影响下混合料界面细观损伤特征规律；采用四点弯曲疲劳试验与数字图像相关方法，分析了不同粗集料接触参数的混合料细观变形分布特征以及其疲劳损伤破坏机理。提出了粗集料接触参数推荐范围（10.97%~13.62%）。提出了沥青混合料细观疲劳损伤定量评价方法。本项目揭示了粗集料接触参数对沥青混合料的细观损伤机制的影响，为沥青路面的寿命预估与材料优化设计提供了理论依据。

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