Study on the Effect of Chloride Ions on the Durability of Reinforced Pozzolanic Concrete Members in Coastal Environments

Steel reinforcement corrosion induced by chloride ingress in coastal environments is the dominant factor leading to the durability degradation of concrete structures. In this study, Ordinary Portland Cement (OPC) concrete beams and Portland Pozzolana Cement (PPC) concrete beams were used as test specimens, subjected to sustained loads to induce cracks, and exposed to accelerated reinforcement corrosion through 10 wet–dry cycles using a 3% NaCl solution. Testing methods including half-cell potential, corrosion current, and acoustic emission signals were employed to quantify the likelihood and progression of reinforcement corrosion. The results show that the half-cell potential of the loaded PPC beams remained below −350 mV, with a corrosion current density exceeding 0.5 μA/cm2, indicating a significantly higher corrosion risk than that of the OPC beams; under unloaded conditions, the half-cell potential of the PPC beams remained consistently above −200 mV, with a corrosion current density below 0.2 μA/cm2, exhibiting superior corrosion resistance. The event counts in the acoustic emission tests additionally revealed the progression of chloride ions gradually penetrating and corroding the steel reinforcement. Although PPC beams exhibit lower early-stage crack resistance under loading conditions and are prone to forming more cracks, their advantage in resisting chloride ingress becomes significant after appropriate mitigation measures are implemented to reduce early crack formation, making them remain a preferred material for reinforced concrete members in coastal environments.