Effect of Sodium Nitrite as a Corrosion Inhibitor in Reinforced Concrete in the Presence of CO2 and Chloride

Cristiane Resende, Victor Hugo M. da Silva, Patrícia B. Martelli, Alysson Helton S. Bueno
2018 Revista Virtual de Quimica  
The emission of carbon dioxide ( 2 ) and the marine environment have aggravated the corrosion in reinforced concrete structures. In this way, an alternative to reduce or prevent corrosion has been the use of inhibitors, because they are able to extend the period of initiation of the process that involves oxy-reduction reactions, reducing the general rate of corrosion. In this study, the objective was to evaluate, through electrochemical techniques (curves of potentiodynamic polarizations and
more » ... ctrochemical impedance tests), the behavior and the efficiency of corrosion inhibitor for concrete in marine environments and with pollution by carbon dioxide ( 2 ). The synthetic inhibitor sodium nitrite ( 2 ) was tested at concentrations of 3 and 4 % (m.v -1 ). Samples of evidence of concrete with steel 1020 were used, adding the inhibitor 2 in the concrete mixing water. Then, they were immersed into solutions of 3.5 % (m.v -1 ) sodium chloride ( ) and subsequently bubbling of ( 2 ). Mechanical tests (compressive strength, porosity and water absorption) were carried out with the aim of assessing the influence of the inhibitor on the mechanical properties of concrete. The inhibitor 2 was effective in the presence of only . However, with the addition of ( 2 ), for the tested concentrations of the inhibitor, it has not been possible the passive film formation. The mechanical tests carried out showed that the presence of the inhibitor 2 alters significantly the resistance to compression, reducing their values, though the values of porosity and water absorption showed little variation. restricting the applicability of the concrete with the inhibitor.
doi:10.21577/1984-6835.20180105 fatcat:o6tjmx5o5jcb3j722zpsgcbdia