Chloride Binding Capacity of Portland Cement System with Different Content of Tricalcium Aluminate

The binding of chloride ion has been reported as an effective way to reduce the risk of steel corrosion induced by the utilization of marine sources. In this study, effect of tricalcium aluminate (C 3 A) on chloride binding capacity of Portland cement paste was investigated; the setting time, compressive strength, and fluidity of cement-C 3 A system were also examined. The reaction mechanism of C 3 A and chloride ions was studied by X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). The results showed that addition of C 3 A in cement paste could increase the compressive strength not only at the early age but also at the late age. The setting time was shortened obviously and the fluidity was reduced. The main reason was that fast hydration of C 3 A could hasten the formation of ettringite to consume free water, and also promote the hydration of the system. Furthermore, addition of C 3 A in cement paste could greatly promote the chloride binding capacity, and the main reason was due to the promoted formation of FS in hydrates. The investigation was expected to provide experience in promoting the chloride binding capacity of cement system.