Reinforced Concrete (RC) structures in marine environments deteriorate rapidly due to chloride-induced corrosion, requiring performance-based mix and cover design for environmental sustainability and reduced life-cycle costs (LCC). A probabilistic performance-based framework is presented in this study to predict and compare the service life, LCC and equivalent carbon dioxide emissions (CO2-e) of concrete mixes with different binder compositions in harsh marine exposures. Concrete mixes with varying proportions of supplementary cementitious materials (SCMs) like fly ash and slag were tested for strength, chloride diffusion, and electrical resistivity. Using the results, a probabilistic analysis was conducted on a typical coastal structure with a 50-year design service life considering a range of commonly practiced covers. The time-dependent failure probabilities for initiation and propagation were evaluated using Monte Carlo Simulation, applying patch repair when the first corrosion-induced crack appears. Material Sustainability Indicators (MSI) were assessed in terms of LCC and lifetime carbon emissions. The findings demonstrate that a 25% fly ash replacement notably enhanced the cost-effectiveness of structures by delaying the time to cracking and reducing the repair frequency. Combined with larger cover, high volume replacement led to a reduction of around 60% in CO2 emissions. This research highlights the need for performance-based mix designs to minimize long-term costs and environmental impact for RC structures in harsh, marine exposure.

Reinforced concrete, chloride induced corrosion, life-cycle costs, cover thickness, service life, CO2-e, supplementary cementitious materials