Development of design service life prediction models for reinforced concrete structures subjected to chloride penetration considering the influence of the effects produced by loading states

• Grant number: 23/13393-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2023
• End date: November 30, 2024
• Field of knowledge: Engineering - Civil Engineering - Structural Engineering
• Principal Investigator: Caio Gorla Nogueira
• Grantee: Amanda Corrêa Tavares
• Host Institution: Faculdade de Engenharia (FE). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

Nowadays, reinforced concrete is the most used material in the world for structural purposes, due to its relative low production cost, good structural resistance, suitability for imposed shapes and good durability when inserted in low and moderate aggressive environments. However, as the environmental aggressiveness increases, such structures may have their useful life and, therefore, durability affected due to the attack of chemical agents present mainly in the atmosphere of industrial and coastal regions. Among the various agents that can trigger the emergence of pathologies in concrete, chloride ions are considered the main ones, since, through the ionic diffusion process, they penetrate the interior of the concrete, initiating the electrochemical corrosion of steel reinforcement, from of a certain concentration that depassivates the reinforcement. The main mathematical model used to study ionic diffusion in concrete is Fick's second law, governed by a diffusion coefficient that depends on multiple factors related to: the composition and age of the concrete, environment and service conditions, among them, the stress/strain states, as well as the concrete damage level. The influence of stresses and damage on the diffusion coefficient is still little known and requires deeper investigation, being the focus of some recent studies in the area of reinforced concrete structural durability. Allied to this, service life prediction models can be important tools that move towards quantifying the durability of these structures. In this context, this proposal presents a deterministic study on the corrosion initiation period in reinforced concrete beams in service, considering the influence of stress state and damage variables on the chloride concentration, to predict the service life. The effects of the stress state and damage of the concrete will be determined for beams of interest, using a computational program via non-linear FEM, with subsequent inclusion of these effects on the concrete chloride diffusion coefficient. The service life will be defined as the period necessary for corrosion initiation of the reinforcement.