A state-of-the-art review of self-healing stimuli-responsive microcapsules in cementitious materials

Cracking is a recurring defect that typically arises during the construction and service periods of cementitious materials. Self-healing based on stimuli-responsive microcapsules has shown to be a cutting-edge technology to make cementitious materials sustainable. Despite the reported implementation of microcapsules in various fields, the strategies toward self-healing of cementitious materials via embedding microcapsules remain a significant challenge. Given this, a review concentrating on the healing exploration of cementitious materials assisted by self-healing stimuli-responsive microcapsules is conducted to bridge the gap. Special attention is given to the encapsulation designs and preparation processes, followed by capsules’ response mechanisms and healing processes. In particular, application scenarios, challenges and future prospects of self-healing stimuli-responsive microcapsules for cementitious materials are summarized and proposed in detail for the first time. This review attempts to better grasp the future research direction of this field, which provides new perspectives for addressing the cracking issue of cementitious materials.