Behavior of galvanized reinforcements in carbonated and non-carbonated media

The present work aimed to study the electrochemical behaviour of galvanized reinforcements in carbonated and non-carbonated media of different alkalinities. For this purpose, galvanized steel bars with 6.3mm of diameter, cut into 100 mm segments, were used. The reinforcements were immersed in saturated solutions of calcium hydroxide and potassium hydroxide, simulating the liquid phase of the concrete pores. The electrochemical behaviour of the reinforcement was evaluated in environments with potentials of hydrogen (pHs) ranging from 12.6 to 13.5. These reinforcements were monitored by means of electrochemical measurements using the linear polarization resistance technique. The results showed that galvanized bars only passivate at pHs lower than 13.2. It has also been observed that, in carbonated environment, with a pH of about 8.5, there is a low probability of corrosion of the galvanized reinforcements, what does not take place for carbon-steel reinforcements. This demonstrated that galvanized reinforcements can be used in environments subjected to carbonation, but this should be done with caution when there is a possibility of high levels of alkalinity, depending on the used materials Copyright (C) 2018 Elsevier B.V. All rights reserved.