Influence of GFRP Confinement of Reinforced Concrete Columns on the Corrosion of Reinforcing Steel in a Salt Water Environment

Abstract

This paper concentrates on the changes on the corrosion rate of the steel bars of RC columns due to their wrapping with glass fiber–reinforced polymers (GFRPs). RC cylindrical laboratorial specimens, both unwrapped and wrapped with GFRP, were immersed in a sodium chloride solution for 20 months. The changes on concrete resistivity and the corrosion process were followed by open potential measurements and electrochemical impedance. It was possible to quantify the influence of the GFRP jackets in the solution uptake and on the corrosion of the steel reinforcement. The results showed a delay on the diffusion of the solution into concrete due to the presence of the GFRP, which allowed that the bars remained in a passive state for longer immersion periods. The GFRP barrier lowered the rate of uptake of the solution and the chloride ion penetration. However, the GFRP jacket may have the properties as a physical barrier reduced due to imperfect application. The incomplete concrete saturation makes oxygen available, thus promoting an intense corrosion activity at the rebars.