Statistical Study of Corrosion Types in Constructions in South Region of Rio De Janeiro

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The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

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For this type of steel, the electrochemical mechanism of corrosion process originates in the form of localized corrosion (crevice) usually associated with electrolyte stagnation conditions in microenvironments where there is hindrance or difficulty to the spread of chemical species.

The solution within the crack is deoxygenated due to initial corrosion that consumes, through cathodic process, the oxygen in solution: O2 + 2H2O + 4e 4OH-. The oxygen diffusion rate into the crack is not fast enough to replenish the oxygen consumed in the cathodic process. The cathodic process moves out of the crack where oxygen is plentiful. There is separation of anodic and cathodic regions.

The ferrous ions are formed within the crack (Fe Fe ++ + 2e-) and hydroxyls in oxygenated regions.

The ferrous ions undergo hydrolysis (Fe ++ + H2O Fe (OH) + + H+) and decrease the pH within the crack. Due to the current flow and mass transport phenomena, aggressive ions migrate under the influence of electrostatic field into the crack, and are concentrated there, causing great changes in chemical conditions.

As a result there is the iron hydroxide (II), white color, which due to the oxidation process is turned slowly into iron hydroxide (III), which has a brown-orange coloration according to the iron content (III) .When this type of coloring appears in structures (concrete and steel), it indicates that they are suffering corrosion. The oxidized iron assumes that color and begins to crumble. In the affected areas, the metal will lose density and, if the process is not contained, it can reach the full degradation.

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Mangaratiba

Engenheiro Paulo de Frontin Mendes Vassouras Miguel Pereira Areal Comendador Levy Gasparian Paraty Angra dos Reis

Sapucaia Paty do Alferes

Rio das Flores

Rio Claro

Porto Real Itatiaia Pinheiral Resende Quatis Volta Redonda Barra Mansa

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Fig. 15. Numbers of employees in some cities in the southern state.

[9] de Macena Rezende, D. (2014).

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C., Gomes, L. A. V., Nascimento, P. A. M. M., & Toledo, Novos Estudos-CEBRAP, (98), 43-67.

-2011. Base de Dados.

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Cite the paper Silva (2016). Statistical Study of Corrosion Types in Constructions in South Region of Rio De Janeiro Brazil. Mechanics, Materials Science & Engineering, Vol 7. doi: 10.13140/RG.2.2.29609.60004

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