Summary:  Chloride-induced corrosion of steel reinforcement in concrete is the major cause of deterioration of reinforced concrete structures, especially bridges exposed to the sea and/or de-icing salts; and significantly reduces structure durability. In order to implement sustainable bridge management it is necessary to determine service life of structures using numerical models. The main aim of the project is to improve the 3D chemo-hygro-thermo mechanical (CHTM) model for realistic simulation of  processes before and after  depasivation of reinforcement bar in concrete. The project includes: literature review; visual inspections and investigation works on reinforced concrete bridges combining measurements of damages in concrete, half-cell potential, electric resistivity of concrete and chloride content in concrete; laboratory testing on permeability of cracked concrete; and numerical modelling of transport and corrosion processes in reinforced concrete structures, taking into account damages in concrete.

Project activities are focused on achieving the following objectives:

• • • Development of an improved model of the water and chloride diffusion coefficient for concrete as a function of crack width based on the laboratory testing on permeability of cracked concrete and investigation works on the bridges;

    • Determination of characteristics of the cracks and voids in concrete on the structural elements of the inspected bridges including geometry, but also causes of concrete defects;

    • Determination of the structural elements of the bridges that are the most vulnerable to cracking and other damages in concrete based on the performed ultrasonic testing on the bridges and numerical modelling;

    • Determination of the structural elements of the bridges that are the most vulnerable to reinforcement corrosion based on the measurements of the half-cell potential of steel rebar and electric resistivity of concrete on the existing bridges;

    • Development of an empirical model of the impact of the concrete cracks on reinforcement corrosion based on the performed measurements of cracks in the concrete, electric resistivity of concrete and half-cell potential of steel rebar;

    • Development of numerical models to simulate transport and corrosion processes in reinforced concrete structure including modelling of realistic cracks as well as more precisely determination of the initial and boundary conditions based on the results of the measurements on the bridges and using improved model of the chloride and water diffusivity. 

New knowledge obtained from the experiments, the measurements and the numerical modelling will be useful to scientists, public sector and industry dealing with the global problem of chloride induced corrosion of steel in concrete.