Smart releasing behavior of a chemical self-healing microcapsule in the stimulated concrete pore solution

A novel chemical self-healing system based on microcapsule technology for cementitious composites is established. The key issue for such a system is how to release the healing agent and how to activate the healing mechanism. The present study focuses on the release behavior. The smart release behavior of the healing agent in the microcapsule is characterized by the EDTA (Ethylene Diamine Tetra-acetic Acid) titration method. The experimental results show that the release of the corrosion inhibitor covered with polystyrene resin (PS) is a function of time, and is controlled by the wall thickness of the microcapsule. Moreover, the pH value affects the release rate of the corrosion inhibitor; the release rate remarkably increases with the decreasing pH value.