Development of Mathemati̇cal Models for the Chemi̇cal Ki̇neti̇cs of Corrosi̇on i̇n Rei̇nforced Concrete Structures

This article focuses on the mathematical modeling of the chemical kinetics processes in the interaction of seawater containing chloride, an aggressive environment, with reinforced concrete structures equipped with steel reinforcement. The objective is to refine the mathematical models of the corrosion processes of steel reinforcement in reinforced concrete structures using the fundamental equations of the chemical kinetics of steel oxidation. The study presents a comparative analysis of known mathematical models, indicating that most of them are formal models obtained through the approximation of experimental data. As known, the use of formal mathematical models in scientific research is limited, as these models cannot adequately describe the dynamics of processes in other modes. The evaluation of known models was carried out through the analysis of the structure of mathematical models, the presence of zero initial conditions of differential equations, and the comparison of model structures with chemical kinetics equations. Within the study, a new mathematical model of the dynamics of the corrosion depth change of steel reinforcement under the influence of seawater with an aggressive environment has been developed. This model is presented in the form of a nonlinear differential equation with ordinary derivatives. The scientific contribution also includes analytical solutions for the nonlinear differential equation with ordinary derivatives, considered for two corrosion components instead of four, under the influence of seawater with an aggressive environment.