Naslov
Application of carboxylic acids as inhibitors for chloride induced reinforcing steel corrosion

Autori
Valek, Lidija ; Martinez, Sanja ; Serdar, Marijana ; Stipanović, Irina

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Eurocorr 2007, Progress by Corrosion Control / - Freiburg, 2007

Skup
Eurocorr 2007

Mjesto i datum
Freiburg, Njemačka, 09.09.2007. - 13.09.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
corrosion; reinforcing steel; inhibition; carboxylic acids

Sažetak
Reinforcing steel corrosion in chloride contaminated concrete is one of the major issues in prolongation of durability of concrete structures. Presence of chloride ions can cause severe damage to the reinforcing steel functionality through the localized attack of the steel passive oxide film, where pitting corrosion can appear as major destruction pathway. The latest trends in reinforcing steel inhibitor research point towards the importance of application of organic molecules with less environmental hazards, like some carboxylic and amino acids. The major goal of present research is investigation of the inhibitory action of few carboxylic acids (ascorbic, benzoic, 4-hydroxybenzoic, salicylic, glutaric, tartaric, sorbic, glycolic, maleic acid) in simulated pore solution. Linear polarization measurements revealed that the presence of carboxylic acids shifted pitting potential by c.c.a. 300 mV towards more positive values, compared to the inhibitor-free system. Some molecules also showed tendency of reducing cathodic oxygen reduction reaction, especially ascorbic acid. Cyclic voltammetry measurements enabled useful insight into the mechanism of action of a particular molecule. It is known that carboxylic acids have the ability to form complexes with iron species thorough the carboxylic group. The stability and solubility of Fe(II) or Fe(III) complexes determines the inhibitory action of a particular molecule. Increase or decrease of a specific current peak could be taken as indicative of inhibitor molecule activity and changes in the oxide film induced by the presence of inhibitor. The highest inhibitor activity was exerted by ascorbic acid that has diminished all the redox peaks in cyclic voltammogram and was also confirmed to be most effective by electrochemical impedance spectroscopy.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Građevinarstvo, Kemijsko inženjerstvo

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