Influences of cementitious capillary crystalline waterproofing on the hydration products and properties of cement-based materials

• Published in: Journal of Building Engineering 2024-12, Vol.98, Article 111451
• Main Authors: Zhong, Jingru, Zhang, Huaxian, Mao, Juejue, Zhang, Yanlin, Lian, Songsong, Wang, Jiaze, Zhou, Hangjie, Song, Yufeng, Hu, Jiawen, Wu, Haihua, Ruan, Shaoqin
• Format: Article
• Language: English
• Subjects: Cementitious capillary crystalline waterproofing; Microscopic morphology; Physical composition; Pore structure; Self-healing
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2024.111451

Admixtures and curing conditions affect the self-healing ability of concrete. In this research, various doses of XYPEX-type CCCW and self-healing treatments via internal and external doping were administered. The mechanical characteristics, mineral phases, and pore structures of the samples were unveiled, with the self-healing process assessed through strength tests and a series of microscopic characterizations. The outcomes revealed that concrete specimens incorporating 2 % internal CCCW exhibited the most effective self-healing effect (∼114.4 %). The enhancement in specimen mechanical properties correlated with microstructure refinement, resulting in increased hydration product generation, microcrack filling, and diminished macropore spaces. These findings underscore CCCW's superior reactivity compared to cement particles, emphasizing the advantages of a moderate internal CCCW admixture in prolonging concrete lifespan. Furthermore, the self-healing rate of the specimens is contingent on the diffusion rate of Ca2+ across the concrete's boundary layer and CaCO3. Elevated calcium ion concentrations precipitate denser boundary layer growth, hindering calcium ion penetration for self-healing. •CCCW enhances hydration, increasing C-S-H and CaCO3 production.•2 % CCCW significantly boosts concrete's self-healing and durability.•Higher CCCW concentrations initially boost, then hinder, mechanical properties.•Effective CCCW dosages improve calcium ion diffusion for crack repair.