"Influência de inibidores no comportamento de corrosão de aço CA-50 para armadura de estruturas de concreto" / Evaluation of the potent ial of addi tives as corrosion inhibitors of CA-50 carbon steel used as reinforcement in concretes.

AUTOR(ES)

Marina Martins Mennucci

DATA DE PUBLICAÇÃO

2006

RESUMO

In this work, various compounds were tested to evaluate their potential capability for their use as corrosion inhibitors of carbon steel reinforcement in concretes. The addit ives tested were sodium benzoate, polyethylene glycol, hexamethylenetetramine, benzot riazole and itrium carbonate. Initially, exploratory tests were carried out to select the ones to be used as corrosion inhibitors, based on the inhibit ion ef f iciency determined from elect rochemical tests, specifically polar ization tests and elect rochemical impedance spect roscopy. These tests were carried out in a solut ion composed of 0.01N sodium hydroxide (NaOH) and 0.05N potassium hydroxide (KOH) to simulate the composition of the solution inside the pores in concretes. The additive that presented the most promising potent ial to be used as cor rosion inhibitor was benzot r iazole (BTA). Af ter the elimination of some compounds and selection of the additive with higher corrosion inhibit ion efficiency in the test medium, the effect of its concent ration on the cor rosion inhibition efficiency was evaluated. Sodium nitrite solutions with the same concentrat ions as those solutions with BTA were tested for compar ison reasons. Sodium nitr ite is a well established corrosion inhibitor for carbon steel reinforcement in concretes but it has been related to toxic effects. The BTA was associated to higher corrosion inhibit ion efficiencies than that of sodium nitrite in similar concentrations. A blackish adherent film was formed on the steel surface exposed to BTA solut ions dur ing long periods of immersion in the alkaline medium. The results suggest that BTA is a potential candidate for subst itution of nit rites as corrosion inhibitor of reinforcements in concrete

ASSUNTO(S)

carbon steel corrosion aco carbono inhibitors corrosao inibidores

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