Preparation and properties of cement mortar/ metal hydroxide microcapsules composites

Abstract

Metal hydroxide microcapsules have been found to possess good sustained-release property, and they could delay the decline of pH values in the pore solution of mortar. In this paper, these metal hydroxide microcapsules were incorporated into cement mortar and It was found that they had no obvious effect on the mechanical properties. In linear sweep voltammetry (LSV) curves, all samples with microcapsules had higher corrosion potential (Ecorr) and corrosion resistance (Rp) values as well as lower corrosion current density (Icorr) values compared with blank sample without microcapsules. These results revealed that the microcapsules had an obvious anticorrosion effect on steel rebars in mortar. EIS tests showed that the anticorrosion effect of metal hydroxide microcapsules was affected by microcapsules dosages and the type of core materials. Compared with the samples with uncoated pure hydroxide, the steel rebar with metal hydroxide microcapsules had higher Ecorr and Rp values, lower Icorr and larger charge transfer resistance values. The corrosion surface on the steel rebars in mortar also confirmed the above conclusion.