Seawater-mixed concrete – A review with focus on durability properties

Freshwater scarcity remains a major global concern, particularly in coastal regions. Utilizing seawater for concrete production offers a sustainable approach to conserve freshwater resources while supporting construction in marine environments. This study conducts a systematic and data-driven review of seawater-mixed concrete research using the Scopus database, focusing on durability aspects. The analysis reveals that seawater accelerates the early hydration of ordinary Portland cement (OPC) due to the ionic activity of Cl⁻, Na⁺, and Mg²⁺, leading to a denser early-age microstructure and enhanced initial strength. However, long-term strength and durability outcomes remain inconsistent across studies, influenced by curing conditions, ionic composition, and mixture design. Seawater-mixed concrete generally exhibits improved sulfate resistance but shows variable carbonation behavior and increased susceptibility to alkali–silica reaction (ASR), shrinkage, and freeze–thaw damage. The incorporation of supplementary cementitious materials (SCMs) such as metakaolin (MK), fly ash (FA), and ground granulated blast-furnace slag (GGBS) enhances chloride binding and refines the microstructure, mitigating some adverse effects. Overall, this review identifies key research gaps in long-term durability and emphasizes the need for standardized methodologies and data-driven investigations to optimize seawater-mixed concrete for sustainable coastal and marine infrastructure.