基于磁响应控释微胶囊的沥青材料多次自修复研究

Asphalt aging and fatigue cracking are the common forms of distresses in flexible pavements. A number of studies have shown that the feasibility and potentiality of asphalt materials self-repairing by microcapsules containing rejuvenators. However, the prerequisite is crack propagation through the microcapsules and resulting in the broken of microcapsules, which is a passive release and a single repair. Especially, the microcapsules are powerless for asphalt recycling while pavements do not creak. In view of the above problems, this project aims to establish the principle and technology of active controlled release of microcapsules clear, and realize the active prevention and repeated self-repairing of asphalt materials with aging or cracking. This research mainly includes the following contents: (1) Preparing the magnetic responsive controlled release asphalt self-healing microcapsules inspired by the working principle of heart; (2) Based on the releasing process and quantitative analysis, the releasing mechanism and release kinetics would be established. (3) By analyzing the effect of controlled release microcapsules on the repair of asphalt material properties and their ultimate ability, the method of asphalt mixture design mixed with controlled release microcapsules and control mechanism would be developed for engineering applications. The study aims to overcome the problems of the synthesis of magnetic response of asphalt self-repairing microcapsules and its controlled release. Research results will provide a new research method and theory foundation for asphalt pavement intelligent maintenance.

沥青老化、疲劳开裂是沥青路面主要病害。诸多研究采用内含再生剂的微胶囊实现病害自修复，但前提是路面产生裂缝且能引发囊壁破裂，其实质是被动释放和单次修复，而且大量位于裂缝扩展路径之外的微胶囊不能起到修复作用，同时对路面未产生裂缝时老化沥青的再生也无济于事。针对以上问题，本项目力图建立磁响应沥青自修复微胶囊主动控释原理和技术，并以此为基础，实现针对沥青老化、裂缝等病害主动预防和多次修复。主要研究内容包括：(1)借鉴心脏收缩-恢复工作原理，研发磁响应控释沥青自修复微胶囊；(2)基于磁场作用下微胶囊释放微观过程和释放物定量测定，明晰微胶囊磁响应机理，建立释放动力学方程；(3)分析控释微胶囊对沥青材料性能修复作用和极限能力，形成指导工程应用的掺配控释微胶囊的混合料设计方法和控释机制。研究成果旨在攻克磁响应沥青自修复微胶囊制备及其主动控释这一关键科学问题，为沥青路面智能养护提供新的理论基础和技术支撑。

沥青老化、疲劳开裂是沥青路面主要病害。诸多研究采用内含再生剂的微胶囊实现病害自修复，但前提是路面产生裂缝且能引发囊壁破裂，其实质是被动释放和单次修复，而且大量位于裂缝扩展路径之外的微胶囊不能起到修复作用，同时对路面未产生裂缝时老化沥青的再生也无济于事。针对以上问题，本项目借鉴肿瘤热疗药物运输系统工作原理，建立了磁响应沥青自修复微胶囊主动控释和制备技术机理；在该理论基础上，基于改进的原位聚合法，研发了“蜂巢”结构磁响应控释沥青自修复微胶囊，并从其物化性能和控释效率两方面优化微胶囊设计；采用高频交变磁场作为微胶囊的控释方法，提出了控释微胶囊释放行为的定量测定方法，研究了微胶囊释放效率的关键影响因素，建立了释放动力学方程，实现沥青自修复微胶囊的高效主动按需释放；分析控释微胶囊对沥青材料的性能影响，形成指导工程应用的控释微胶囊掺配方法。研究成果实现了针对沥青老化、裂缝等病害主动预防和多次修复，攻克磁响应沥青自修复微胶囊制备及其主动控释这一关键科学问题，为沥青路面智能养护提供新的理论基础和技术支撑。