Characterization and quantification of self-healing behaviors of microcracks due to further hydration in cement paste

It has been reported by previous studies that cracks in cementitious materials can be healed by further hydration of unhydrated cement particles. However, by now, neither the physicochemical process nor the potential of self-healing due to further hydration is completely understood. In this paper, in order to gain insight into self-healing by further hydration, healing behaviors due to further hydration were characterized and quantified. The mineralogy of healing products was qualitatively determined and the percentage of each mineral was specified. The formation of healing products as a function of time was quantified as well. Moreover, self-healing of microcracks was simulated by a reactive transport model. The calculated filling fraction by the healing products in microcracks was consistent with the experimental results. The healing process slowed down markedly after 300 h. In addition, in younger cement pastes, larger amounts of unhydrated cement lead to greater filling fraction of microcracks.