Construction of corrosion degree model and mechanical properties random model of non-uniform corroded reinforcement under multi-factor coupling

Abstract

In order to improve the prediction accuracy of the theoretical model on steel corrosion degree, the multiple correction coefficient method was used to establish a piecewise constitutive model based on electrochemical signal of stressed reinforcement. Through “micro fault microstructure” analysis, the non-uniform local corrosion surface characteristics and evolution mechanism of rapid propagation of micro cracks and “Transgranular failure” of stressed reinforcement were deeply revealed. The “external macro surface characteristics and internal micro crystal structure” of corroded reinforcement were related. Based on micromechanics theory and failure criterion of macro deformation, the micro mechanism of micro crack propagation under the coupling effect of internal and external factors (e.g. micro defects, stress state) were revealed, and the essence of macro “low stress brittle fracture” was induced. The influence factors of time-varying and material heterogeneity of the real bridge were introduced, and the “random time-varying model” of mechanical properties of corroded reinforcement under the coupling effect of stress corrosion and material heterogeneity was constructed. Combined with previous visualization method, the “electrochemical signal non-uniform corrosion characteristics mechanical property degradation” was related to form a “three-dimensional time-varying model,” which provided guidance for engineering application.