Effect of Hydrated Calcium Aluminate Cement on the Chloride Immobilization of Portland Cement Paste

To improve the efficiency and stability of chloride immobilization of portland cement paste, hydrated calcium aluminate cement (HCAC) prepared by wet grinding of CAC was added into portland cement paste as an additive. The immobilized chloride ratio (ICR) was evaluated, and the mechanism of chloride immobilization was researched by XRD, DTG, NMR, and MIP tests. The analysis results demonstrated that HCAC could improve the chloride immobilization capacity of portland cement paste. The mechanism was attributed to the following aspects: chemical binding capacity was enhanced via producing more Kuzel’s salt; physical adsorption capacity was reduced by decreasing the C-S-H gel; migration resistance was enhanced through refining the pore structure.