自修复增强型活性水泥颗粒微胶囊封装及长时效机制研究

利用自修复技术解决重大混凝土工程的裂缝病害对节约资源、能源、保护环境具有重大意义，而抑制环境水分侵蚀、延长活性水泥颗粒的修复时效是实现其在重大混凝土工程中实用化发展的主要关键。基于粘附-乳化-界面聚合法合成活性水泥颗粒为囊芯、聚合物为囊壁微胶囊的前期研究工作，本项目从多尺度调控聚合物的微结构进而提升囊壁的致密性和化学稳定性，旨在建立囊壁结构与微胶囊在混凝土中稳定性之间的构效关系，实现活性水泥颗粒在长龄期混凝土中仍然保留自修复能力；采用单裂纹法研究微胶囊释放的活性水泥颗粒在微裂纹内的分散和水化机制，并结合四点弯曲法评价混凝土的力学性能自修复效果，实现微胶囊的长时效机制研究。本项目重点研究强碱环境中聚合物囊壁结构和性能的改变对微胶囊稳定性及其对水分子扩散过程的抑制机制，探明活性水泥颗粒通过分散与水化协同作用实现混凝土微裂纹的填充和粘接机理，为重大混凝土工程的百年安全运行提供理论基础和技术支持。

Self-healing is a newly developing technique to solve cracking issue in large-scale concrete engineering, due to its resource conservation, energy saving and environmental protection. Extending the service life of activated cement particles is inevitable for its practical application in self-healing concrete. Based on the successful fabrication of microcapsules with cement particles as core material and polymers as shell material through adhesion-emulsification-interfacial polymerization method, this project is to adjust microstructures of polymer shells for better impermeability and chemical stability of microcapsules in concrete. The hydration process of cement particles in single crack is observed and investigated systematically. In addition, the mechanical recovery is applied to evaluate the healing performance of final microcapsules in concrete. This project focuses mainly on the water retardant mechanism of shell with degradative structure in alkali environments. The self-healing mechanism will also be uncovered by studying the dispersion and hydration process of activated cement particles in concrete microcracks, providing theoretical contributions and technical support for long-durable large scale concrete engineering.