Chloride-induced corrosion resistance of calcium sulfoaluminate belite-based binders

Calcium sulfoaluminate belite (CSAB) cement is an alternative to Portland cement (PC) with lower embodied carbon dioxide. In this work, the chloride-induced corrosion resistance of steel bars embedded in PC-based and CSAB-based binders was investigated. The PC-based binders were formulated by blending an expansive CSAB-based admixture (15% ye’elimite) with PC, whereas the CSAB-based binders were formulated based on non-expansive CSAB cement (49% ye’elimite) as the sole binder. The corrosion resistance of steel embedded in different binders of compressive strength 28–32 MPa was evaluated using linear polarisation resistance and open circuit potential. The corrosion resistance of steel reinforcement embedded in CSAB-based binders was observed to be lower than that in PC-based binders. The low pH and large amount of sulfates present in the CSAB-based systems negatively impacted its corrosion resistance. The addition of calcium hydroxide marginally improved the corrosion resistance of CSAB-based binders owing to an increase in the pH of the system.