Research on multi-parameter quantitative forecasting model of reinforcement corrosion in marine concrete structures

Corrosion of steel reinforcement is a key issue affecting the durability and service life of marine concrete structures. To develop a more accurate predictive model for the corrosion rate of steel reinforcement, this study conducted a series of experiments. Specimens with different rebar diameters and concrete cover thicknesses were prepared, and NaCl was added in varying amounts (0 to 0.6%, based on the binder mass, increasing by 0.1%). Two parallel sets of six specimens each (covering different combinations of rebar diameters and cover thicknesses) were made for each NaCl dosage, totaling 84 specimens. The linear polarization resistance (LPR) method was used to test these specimens under the same conditions. The results showed that the relative and absolute corrosion current densities of steel reinforcement in marine concrete generally follow a normal distribution, confirming the reliability of the current research approach. The study also analyzed the effects of free chloride content (\({C}_{\text{f}}\)), cover thickness (C), rebar diameter (D), and exposure time (t) on the corrosion rate. The corrosion current density (\({I}_{\text{corr}}\)) increases with higher free chloride content but decreases with thicker concrete cover, larger rebar diameter, and longer exposure time. Based on these findings, a comprehensive predictive model for the corrosion rate of steel reinforcement in marine concrete structures was developed and validated through significance tests. This model provides a scientific basis for the design and maintenance of marine infrastructure, enhancing the durability of reinforced concrete structures in harsh marine environments.