Carbonation Resistance of Cement-Based Materials Improved by Nitrite

Abstract

Carbonation resistance ability is one of the most important durability-related proprieties of cement-based materials. Through the carbonation depth experiment, isothermal conduction calorimetry, XRD, BET, and water vapor sorption, the effect of calcium nitrite (Ca(NO3)2) on the carbonation properties of cement-based materials is obtained. The result indicates that the addition of Ca(NO3)2 improves the carbonation resistance property of cement-based materials if the hydration of cement pastes and microstructure is modified earlier without affecting the late hydration process. In addition, the refined pores and higher tortuosity cut down the channels, thereby impeding the ingress of carbon dioxide gas into cementitious materials, as confirmed by BET and water vapor sorption. The Ca(NO3)2 exhibits high performance in improving the carbonation resistance and extending the life of strengthened concrete.