Modeling of self-healing efficiency for cracks due to unhydrated cement nuclei in hardened cement paste

Nuclei of unhydrated cement particles left in hardened cement paste after maturation can provide self-healing capability to micro-cracked matrix under favorable conditions. In this present study, a model study is conducted to characterize the influence of hydration reaction of the unhydrated cement nuclei on self-healing efficiency of cracks in hardened cement paste. Based on two different cracking modes of unhydrated cement nuclei, i.e., the splitting crack mode and the dome-like crack mode, the mathematical expressions on the self-healing efficiency are presented from the viewpoint of geometrical probability. Recurring to a generalized hydration reaction model of cement particles, the self-healing efficiency model quantitatively consider the influence of the volume fraction, particle size distribution and cracking modes of unhydrated cement nuclei randomly distributed in hardened cement paste. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Chinese Materials Research Society Open access under CC BY-NC-ND license.