基于离散元虚拟试验的沥青混凝土疲劳断裂机理研究

项目名称： 基于离散元虚拟试验的沥青混凝土疲劳断裂机理研究

项目编号： No.51208178

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 建筑环境与结构工程学科

项目作者： 陈俊

作者单位： 河海大学

项目金额： 25万元

中文摘要： 沥青混凝土疲劳性能一直以来都是道路科技工作者研究的热点。作为一种多相复合材料，混凝土的力学性能在很大程度上取决于集料、沥青胶浆和空隙的体积含量、分布特征等细观结构。但传统的室内疲劳试验不能有效体现上述因素，很难从细观结构角度揭示沥青混凝土疲劳断裂的本质特征。为此，本项目综合运用离散元方法和图像处理技术，开展沥青混凝土虚拟疲劳试验及其疲劳断裂机理的研究。研究内容包括运用离散元方法建立考虑集料不规则形状、级配和体积含量的沥青混凝土小梁数字试件；建立基于离散元法的小梁四点弯曲虚拟疲劳试验方法，并与室内疲劳试验进行对比验证；采用验证后的虚拟试验研究混凝土疲劳断裂过程中其内部细观结构的变化运动规律，以及集料分布特征、形状特征、体积含量、空隙大小和分布等细观结构对混凝土疲劳性能的影响。研究成果不但为沥青混凝土疲劳性能的研究提供辅助分析手段，对揭示混凝土疲劳断裂本质特征亦具有重要的理论价值。

中文关键词： 沥青混合料；疲劳性能；离散元方法；图像处理技术；数字试件

英文摘要： In the past decades, fatigue performance of asphalt concrete (AC) has been extensively studied by many researchers all over the world. As a three-phase material composed of aggregates, asphalt binder and air voids, the fatigue performance of AC is mainly dominated by the volumetric concentrate and spatial distribution of aggregates, asphalt binder and air voids. Previous studies predicting AC fatigue behavior were primarily based on experimental tests, during which, mesostructure of AC cannot be desirably controlled. Therefore, it is necessary to develop digital samples in which the internal structure of AC can be readily controlled for investigating the fatigue failure mechanisms from a mesostructural perspective. This study presents the development of virtual fatigue testing using the discrete element method (DEM) and digital imaging processing technology. The three-dimensional (3D) DEM model of AC is constructed employing a user-defined computer program in the first part of this study. Important mesostructural features of AC are modeled, including aggregate gradation, air voids and mastic. Virtual fatigue method for four point bending test is developed and validated by laboratory tests in the second section of this study. Thirdly, the change of mesostructure in the 3D digital beam during fatigue process and

英文关键词： Asphalt Mixture；Fatigue Performance；Discrete Element Method；Digital Imaging Processing；Numerical Sample