Evaluation of Resistance to Chloride Attack of Concrete Repair Method Using a Combined Application of Silicone-Based Water Repellent

This study aims to evaluate the effectiveness of combined repair methods in improving the durability of reinforced concrete (RC) structures exposed to chloride-induced deterioration. The hydrophobic performance of the applied repair systems was quantified through contact angle measurements, while chloride penetration resistance was evaluated using the non-steady-state chloride migration test (NT-BUILD 492). The results showed that the application of a silicon-based water repellent significantly enhanced hydrophobicity and reduced chloride ingress, and that these effects were further improved when combined with inorganic-organic hydrophobic materials. Chloride-induced durability analysis demonstrated that the combined application of surface coating, patch repair, and surface impregnation systems markedly improved long-term performance. In particular, the predicted service life increased to 287 years, and the chloride content at a reinforcement depth of 40 mm after 30 years of simulated exposure was reduced to 0.6 kg/m3, confirming the high effectiveness of the combined repair strategy in mitigating chloride-induced deterioration.