A new self-healing agent for accelerating the healing kinetics while simultaneously binding seawater ions in cracked cement paste

摘要

To mitigate the corrosion of steel bars and the erosion of the matrix in cracked reinforced concrete in a marine environment, a new self-healing agent was developed that can not only chemically bind the invading ions in the cracks, but also accelerate the crack closure. The closure ratio of a crack with an initial width of 400 mu m can reach 80% after self-healing for 1 day when the developed CaO-NaAlO2 healing agent was added into the concrete with a dosage of 5% by volume. The value for the references without the self-healing was only about 20%. The fast sealing of cracks can rapidly stop the further ingress of these ions. Moreover, reaction products of self-healing, such as Friedel's salt, Kuzel's salt and brucite, were detected, which indicates that Cl-, SO42- and Mg2+y ions invading into the cracks were bound chemically. Therefore, the risk of steel bar corrosion was decreased.

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