水泥基化学自修复微胶囊系统
Chemical Self-healing Microcapsule for Cementitious System
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摘要: 为了利用微胶囊技术初步实现钢筋混凝土的智能感知和自我修复能力, 延长结构的服役寿命, 从材料智能化着手, 结合微胶囊技术和钢筋缓释剂知识, 设计了一套针对水泥基复合材料的化学自修复微胶囊系统.此系统的核心内容是智能释放行为和可控阻锈机制, 同时建立了智能释放和可控阻锈的评估体系.在水分析化学方法中乙二胺四乙酸 (ethylene diamine tetraacetic acid, EDTA) 滴定法的基础上进行改进, 用来测试微胶囊在不同pH、不同时间和不同囊壁厚度条件下的释放行为, 探索智能释放规律;运用交流阻抗谱的方法来评估微胶囊阻锈效果, 同时以宏观钢筋锈蚀图像对比为佐证.此外, 在交流阻抗谱的基础上, 建立了一个全新的电化学模型, 解释化学自修复微胶囊的阻锈性能.Abstract: To fulfil initially the intellisense and self-healing of concrete for corrosion of reinforcement by means of microcapsule technology, a novel chemical self-healing system based microcapsule technology was designed for cementitious composites, which was accompanied by a chemical trigger mechanism. The fundamental issue of this system was the smart releasing performance in cementitious environment and controlled rebar protection effectiveness against corrosion. The measurements with ethylene diamine tetraacetic acid (EDTA) titration and electrochemical impedance spectroscopy (EIS) method were applied to achieve above targets.Resultsshow that properties of microcapsule are affected by the time, the shell thickness of microcapsule and the pH-values in cementitious environment. Besides, an electrochemical model is built up to explain the anti-corrosion pattern of this microcapsule based selfhealing system.