基于多尺度分析的冷再生沥青混合料强度机理与疲劳失效机制研究

Asphalt pavement cold recycling technology, as one of the core technologies of the comprehensive recycling technology system of asphalt pavement, has drawn increased attention and being widely adopted due to the expanded emphasis on the recycled materials and the demands of energy conservation and environmental protection. However, in contrast to asphalt mixtures and hot recycled asphalt mixtures, cold reclaimed asphalt mixtures are still experiencing relative low uniformity and maturity in terms of basic theory, material design method, and structural design proposal. As the cold reclaimed asphalt mixture received more importance in the pavement structure bearing layer and pavement structure life, the strength mechanism, performance evolution and damage control of the cold reclaimed asphalt mixture are still the essential scientific issues and technical challenges yet to be solved to generate wide application of cold recycled asphalt pavement technology. Based on the multi-scale analysis methods which combined molecular simulation, microscopic test, microscopic simulation and macroscopic performance, this project will reveal the structural composition and strength characteristics of RAP particles, cold reclaimed rubber system and cementing system-RAP interface, and will also explore their fatigue damage evolution rules. Additionally, the fatigue damage propagation law will be explored to achieve the coupling analysis between overall mixture strength and fatigue damage, as well as to clarify the strength mechanism and the intrinsic fatigue failure mechanism of the cold reclaimed asphalt mixture. The project research findings will provide an effective support for the improvement of the basic theory and technical system of the cold regeneration technology of asphalt pavement.

随着对旧料循环利用和节能环保要求的日益重视，冷再生技术作为沥青路面综合再生利用技术体系的核心技术之一，受到越来越广泛的关注与应用。然而与沥青混合料和热再生沥青混合料相比，冷再生沥青混合料在基础理论，材料设计方法以及结构设计体系等方面的统一度和成熟度仍然相对较低。随着冷再生沥青混合料在路面结构承重层和路面结构寿命影响中的地位越来越重要，冷再生沥青混合料的强度机理及其性能演变与损伤控制依然是当前沥青路面冷再生技术规模化推广应用亟待解决的核心科学问题和技术挑战。本项目基于分子模拟+微观测试+细观仿真+宏观性能的多尺度分析手段，揭示RAP颗粒团、冷再生胶体系以及胶结体系-RAP界面的结构组成与强度特性，探究其各自的疲劳损伤演化规律，进而实现混合料整体强度与疲劳损伤的耦合分析，明确冷再生沥青混合料的强度机理与疲劳失效内在机制及其关键影响因素，为沥青路面冷再生技术基础理论和技术体系的完善提供有效支撑。

本项目针对冷再生沥青混合料，基于多尺度分析，探究其内部结构与界面组成，揭示其强度机理，明确其疲劳损伤演化行为，对沥青路面冷再生技术的基础理论与技术体系完善及其推广应用具有重要理论意义和实用价值。本项目基于分子动力学模拟构建了冷再生沥青混合料各组成成分的分子模型，从分子层次研究乳化剂含量、水分、水泥水化产物对乳化沥青和集料与RAP料的界面粘附性能的影响。其次，采用扫描技术获取了不同类型的RAP料颗粒团的内部结构和表面形貌特征，明确了RAP料中老化沥青砂浆和集料的粘附状态；基于微观测试方法明确了冷再生胶（砂）浆内部交织粘聚状态以及不同形式胶结料与集料和RAP料的粘附状态，揭示了RAP颗粒团、冷再生胶（砂）浆体系以及胶结体系-集料界面的微观特征与强度组成机理。最后，进行了冷再生胶（砂）浆和冷再生沥青混合料的力学性能测试，精细化重构了冷再生沥青混合料的数值仿真模型，并开展了考虑沥青砂浆粘结强度、界面折减系数和缺陷走向、长度、位置（高度）等因素影响下的冷再生沥青混合料强度及疲劳失效机理研究，明确了影响其力学性能的关键影响因素。相关研究成果将为冷再生沥青混合料的基础理论完善奠定基础，为高性能冷再生沥青混合料的设计提供理论依据，同时也为冷再生路面结构的合理设计和耐久使用提供有力支撑。