Integrating multiple methods for predicting the electrochemical corrosion evolution of hybrid fiber reinforced concrete under marine exposure environment

Fiber reinforcement effectively improves concrete chloride penetration resistance, while its anti-corrosion performance for steel reinforcements varies with fiber type, dosage and exposure conditions. This study adopted electrochemical tests, COMSOL mesoscale simulation and the grey-theory-based GM(1,1) model to investigate the corrosion evolution of marine hybrid fiber-reinforced concrete. Concrete specimens with single basalt fiber (BF), polyacrylonitrile (PAN) fiber and BF/PAN hybrid fibers were exposed to field marine environments and indoor NaCl dry-wet cycles. Test results revealed that steel corrosion developed rapidly in the early stage and then slowed down, with indoor dry-wet cycles causing the most severe corrosion, followed by tidal and submerged marine zones. The 0.2% BF group presented the best anti-corrosion performance, while excessive BF induced fiber agglomeration and structural defects. Hybrid fiber improved the performance of over-dosed BF concrete but was inferior to optimal single BF concrete. Simulated chloride distributions matched experimental data well, and the GM(1,1) model showed enhanced prediction accuracy with longer exposure time. This work verifies that rational fiber dosage and dispersion, rather than higher fiber content, are critical for the durability design of marine concrete.