Modeling self-healing efficiency on cracks due to unhydrated cement nuclei in cementitious materials: splitting crack mode

Abstract

The nuclei of unhydrated cement particles left in cementitious materials after maturation, can provide a self-healing capability to micro-cracked matrix under favorable conditions. This study is conducted to characterize self-healing effi ciency on cracks in cementitious composites from the viewpoint of a geometrical probability. Based on a practical cracking mode of unhydrated cement nuclei in cementitious composites, the splitting crack mode is presented to deal with the selfhealing effi ciency on cracks due to rehydration of unhydrated cement nuclei. Recurring to a generalized hydration reaction model of cement particles, the self-healing effi ciency model quantitatively considers the infl uence of the volume fraction, particle size distribution and cracking mode of unhydrated cement nuclei, randomly distributed in cementitious materials. Further, the reliability of these theoretical models is verifi ed via computer simulation technology.

Overview of recent work on self-healing in cementitious materials

“…For investigation of the self-healing phenomenon on healing the cracks of matrix, it is necessary to consider the self-healing efficiency or amount of the rehydration product of unhydrated cement nuclei. Based on two practical different cracking modes of unhydrated cement nuclei, i.e., splitting crack mode and dome-like crack mode as respectively illustrated in Figure 6 and Figure 7, theoretical models on the self-healing efficiency of rehydration reaction of the unhydrated cement nuclei were developed by Lv (82)(83)(84). Recurring to a generalized hydration reaction model of cement particles and the particle size distribution of cement approximated by RosinRammler function (85,86), the self-healing efficiency model quantitatively considered the influence of the volume fraction, particle size distribution and cracking modes of unhydrated cement nuclei randomly distributed in hardened cement paste.…”

A phase-field approach for portlandite carbonation and application to self-healing cementitious materials

“…The currently available numerical methods for selfhealing can be grouped according to the nature of their self-healing mechanisms into: (1) chemical reactionbased models, for predicting carbonation [18], further hydration [13,[19][20][21][22][23][24][25], precipitation [26,27] and encapsulation [28][29][30][31]; and (2) transport-based models [18,27], in which the phases affecting the healing processes are transported through the pore-structure network. A few models involve thermodynamics.…”