Modelo de regressão para taxa de corrosão do aço empregado em telas metálicas de sistemas geotécnicos de proteção

Abstract

The importance of the durability of engineering structures is increasingly understood by the technical and socioeconomic influence on the development of the infrastructure, and it has been addressed in the design phase for the forecast of corrosion rate and useful life; and development of maintenance plans. It can be said that the degradation mechanism that most affects this durability is corrosion, which is a natural phenomenon acting on metallic materials. Among the various infrastructure systems, the geotechnical protection structures that use high-strength metallic mesh have their mechanical-functional performance variable throughout its useful life; essentially due to the appearance of pathological manifestations associated with corrosion. The corrosion rate of these systems is, therefore, a fundamental parameter for estimating costs, environmental impact and qualitative viability of construction. The aim of this work is to determine a corrosion rate regression model for the steel of the wire mesh components of slope stabilization systems and protection against rock falls and debris flow. The model was based on linear polarization resistance data and Tafel curves obtained by means of electrochemical tests in simulated environments, and it was subsequently evaluated against the real data of loss of surface galvanizing deposit for meshes exposed in four different environments. The statistical adjustment of the model was performed using the Poisson regression technique, with verification of the respective existing errors. The results allowed the analysis of corrosive processes for different levels of aggressiveness, with independent and joint variation of temperature, concentration of Cl- and Na2SO3. It was found that temperature is the variable that most influences the corrosion rate, followed by the concentration of Cl- and Na2SO3. Finally, it was intended to obtain a regression model that is applicable from the conceptual stages of studying alternatives to the executive project, with their respective maintenance and safety plans for the protection systems.