Steel corrosion development in seawater-mixed mortar

The primary risk of utilizing reinforced seawater concrete is steel corrosion. This study investigates the corrosion development of steel rebars in seawater-mixed mortar with varying water-to-cement (w/c) ratios and cover thicknesses using the wet-dry cycle test. The corrosion behavior of steel rebars was assessed by measuring the free chloride content, half-cell potential, electrochemical impedance spectroscopy, linear polarization resistance, crack width, and steel mass loss. The results reveal that when the w/c ratio was 0.4 and the cover thickness was designed as 10 mm, reinforced seawater-mixed mortar rapidly corroded. Reducing the w/c ratio from 0.6 to 0.4 caused decreased free chloride content, reduced initial corrosion rate, enhanced mortar resistance, slowed corrosion development, and delayed cracking time. A linear relationship was observed between crack width and steel mass loss. The findings indicate that inhibiting the depassivation of steel rebars after casting is key to extending the service life of reinforced seawater concrete.