Impermeability characteristics of cementitious materials with self-healing based on epoxy/urea-formaldehyde microcapsules using an immersion test

A cementitious self-healing system was built using epoxy/urea-formaldehyde microcapsules. The effects of microcapsule content and soaking in chloride on impermeability, pore structure, and self-healing efficiency were investigated. Both microcapsule content and soaking length influenced impermeability and pore structure. With increasing microcapsule content, the impermeability of sound and damaged cementitious composite material specimens increased and then decreased; the impermeability of healing specimens gradually increased. The healing and recovery rates of impermeability increased up to 90 days soaking and then stabilized. Microcapsules positively influenced self-healing but negatively influenced the microstructure of sound specimens. Models to predict microcapsules' effect on pore structure and impermeability were established. (C) 2020 Elsevier Ltd. All rights reserved.