Effect of Nano-Calcium Carbonate on Chloride Binding Properties of Sea Sand Concrete under Chloride Corrosion

The chloride binding properties of sea sand concrete subjected to chloride salt corrosion while taking into account the influence of chloride corrosion duration and nano-calcium carbonate (NC) were studied. The results show that with the increase of chloride corrosion time, the content of free chloride ion and bound chloride ion in sea sand concrete increased gradually. The incorporation of NC could further improve the content of bound chloride ion in sea sand concrete. The content of Friedel's salt and hydrated calcium silicate (C-S-H) in sea sand concrete and the Ca and Si amount of substance ratio in C-S-H increased with the increase of chloride attack time. The content of Friedel's salt in NC sea sand concrete decreased significantly after 14 days of chloride erosion, and the decrease of Friedel's salt content was the most obvious when 1% NC was added. The more NC was incorporated into sea sand concrete, the more obvious the increase of C-S-H content and Ca and Si amount of substance ratio in C-S-H was, which was helpful for the physical adsorption of chloride ions in sea sand concrete.