Optimizing reactive maintenance intervals for the sustainable rehabilitation of chloride-exposed coastal buildings with MMC-based concrete structure

Coastal cities face significant challenges in maintaining their infrastructure due to harsh environmental conditions, such as high humidity and airborne chlorides, which accelerate material degradation. This issue is particularly critical for reinforced concrete structures in beachfront buildings, such as hotels, where corrosion is a common and progressive problem. Timely maintenance and repair are essential to prevent structural failures caused by accidental loads, such as wind or earthquakes, which can compromise safety. Historically, the focus in construction has been on reducing environmental impact, often overlooking the importance of maintenance and end-of-life stages. This paper presents a novel, integrated methodology combining preventive design assessment with reactive maintenance optimization to study the sustainability of repair strategies for maintenance in coastal cities of buildings with reinforced concrete exposed to chloride-induced corrosion. The study focuses on structures based on Modern Methods of Construction (MMC) to minimize life cycle impact by optimizing material consumption compared to traditional construction. Twelve preventive design alternatives are evaluated, each subjected to four maintenance strategies addressing different damage levels caused by deterioration throughout the structure's service life. A FUCOM-TOPSIS model aggregates eight sustainability criteria—economic costs, life-cycle environmental burdens, and social performance indicators—to identify optimal year-by-year maintenance intervals and rank alternatives. Results reveal that the most sustainable designs involve multiresistant cement, hydrophobic anti-corrosion impregnation, and silica fume additive, achieving sustainability ratings up to 86 % higher than the baseline. This approach enhances the resilience and sustainability of coastal infrastructure, effectively addressing challenges posed by harsh environmental conditions and supporting long-term, sustainable urban development. • Evaluated 12 repair strategies for coastal MMC concrete structures exposed to chlorides. • Used FUCOM-TOPSIS model to assess economic, environmental, and social impacts. • Alternatives with multiresistant cement, impregnation, and silica fume improve durability. • Achieved 86 % higher sustainability ratings compared to baseline design options. • Methodology enhances resilience and sustainability of coastal infrastructure.