Abstract: Based on digital image processing technology, the meso-structure of asphalt mixtures was studied. Firstly, the research progress of static and dynamic recognition of asphalt mixture meso-structure was reviewed. Then, a flowchart of digital image processing technology was listed and the method of obtaining the internal structure image of asphalt mixture (X-ray CT technology) was introduced in detail. The research progress in describing the internal structure characteristics of mixture through image processing technology, that is, aggregate shape and distribution, contact characteristics and void distribution rule, was discussed. Finally, the three kinds of numerical simulation methods with finite element, discrete element and boundary element and the virtual test on the meso-structure characteristics of asphalt mixture were introduced. The research shows that X-ray CT non-destructive scanning technology can better identify the internal meso-structure characteristics of asphalt mixtures; the numerical simulation combined with finite element, discrete element or boundary element methods can establish an organic relationship between the internal meso-structure and macro performance of asphalt mixture; the application of virtual test can help to understand the macro test results. However, in the study of aggregate shape and distribution, a unified evaluation index has not yet been formed and different researchers use different evaluation indexes. The accuracy and application scope of X-ray CT technology need to be further improved. There is no effective method to distinguish aggregate, asphalt mortar and void. By summarizing the application of digital image processing technology to the meso-structure of asphalt mixture, it is expected to provide reference for the follow-up macro-meso-micro research of asphalt mixture.

Key words: highway engineering; asphalt mixture; mesoscopic structure; image processing; the numerical simulation

摘要： 基于数字图像处理技术来研究沥青混合料的细观结构，回顾沥青混合料细观结构静态及动态识别的研究进展，其后列出一幅数字图像处理技术流程图并对获取沥青混合料内部结构图像方法(X-ray CT技术)进行了详细介绍；对通过图像处理技术来描述混合料内部结构特征，即集料形状及分布、接触特性和空隙分布规律等方面的研究进展情况进行论述，介绍了运用有限元、离散元和边界元这3种数值模拟方法及有关沥青混合料细观力学特征的虚拟试验。研究表明：X-ray CT无损伤扫描技术能较好识别沥青混合料内部细观结构特征；数值模拟结合有限元、离散元或边界元法能将沥青混合料内部细观结构与其宏观性能之间建立有机联系；虚拟试验应用能很好帮助理解宏观试验结果。在集料形状与分布研究中，尚未形成统一的评价指标，且不同研究人员采用不同的评价指标；X-ray CT技术精度问题和适用范围还需进一步改善；集料、沥青胶浆和空隙这3者之间还未建立有效的区分方法。通过总结数字图像处理技术对沥青混合料细观结构的应用，以期为后续关于沥青混合料宏观-细观-微观研究提供参考。

关键词: 道路工程；沥青混合料；细观结构；图像处理；数值模拟