Self-healing concrete enabled by cementitious capillary crystalline waterproofing materials: a state-of-the-art review

Microcracks significantly compromise the long-term service life of concrete structures, prompting extensive research into mitigation strategies. Embedding healing agents to impart autonomous crack repair capabilities offers a promising solution to reduce maintenance costs and enhance sustainability in the construction sector. Cementitious capillary crystalline waterproofing materials (CCCW), as inorganic rigid waterproofing agents, have garnered increasing attention owing to their excellent waterproofing performance, ease of application, environmental compatibility and cost effectiveness. Recent studies have increasingly recognised the potential of CCCW to impart self-healing functionality to concrete. This review systematically examines recent advances in CCCW-based self-healing concrete, covering the fundamental composition, mix design principles, underlying self-healing mechanisms and the efficacy of crack healing evaluated through various performance metrics and assessment methodologies. Furthermore, future research directions are proposed, providing a theoretical foundation and technical reference to facilitate the industrial application of CCCW.