Electrochemical methods for evaluating inhibitors of steel corrosion in concrete

Dhouibi, L.; Triki, E.; Raharinaivo, A; Trabanelli, G.; Zucchi, F.

doi:10.1179/000705900101501182

Cited by 29 publications

(22 citation statements)

References 2 publications

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“…Several papers have been published on the effectiveness of inhibitors mixed in fresh concrete [1][2][3][4][5][6]. This paper is a complement to previous works [7][8][9], which have shown the inhibiting effect of sodium phosphate and sodium nitrite tested in simulated concrete solutions.The efficiency of these two inhibitors was assessed by using steel specimens in solution simulating concrete pore water and in concrete. The electrochemical tests applied fbr steel in solution were Electrochemical Impedance Spectroscopy (EIS), Polarisation Curves (PC), and Open Circuit Potential measurements (OCP).…”

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confidence: 72%

Studies on corrosion inhibition of steel reinforcement by phosphate and nitrite

et al. 2003

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This work deals with the effectiveness of sodium phosphates and nitrites used as inhibitors against steel corrosion in concrete reinforcement. First, concrete pore water was simulated with several alkaline solutions. Then, reinforced concrete specimens with inhibitors added in fresh concrete mix are immersed in chloride solution. The effectiveness of inhibitors was assessed by applying electroclaemical techniques, namely Eleclrochemical hnpedance Spectroscopy (E[S), Polafisation Curves (PC), and Open Circuit Potential (OCP) measurements. The final concrete condition was analysed with Scanning Electronic Microscopy (SEM), X-Ray Diffraction (XRD) and infrared Spectroscopy (FT-IR).In solutions simulating concrete contaminated with chloride, the influence of the it~aibitors on the steel corrosion was assessed by (PC) and (EIS). The results obtained show that phosphate prevents pitting corrosion when its content is equal to chloride concentration, and that nitrite only contributes to inc~ease the value of pitting potential. Corrosion rate is reduced with both inhibitors at the different contents tested.For reinforced concrete specimens immersed in chloride solution, theft conditions were assessed by applying EIS. The results indicate that after 1 year of immersion with the two inhibitors the corrosion rate decreased. Then, aIter 3 years of immersion no influence ofinhibitors on the corrosion rate was observed. However a significant increase in concrete electrical resistance was obsewed when inhibitors were present. Visual examinations showed that all steel bars were corroded in the presence of chlorides.Results from analytical tests done on the concrete after 3 years of irranersion show that as far as the final concrete condition is concerned, the test~ inhibitors did not change the type of compounds in concrete. But the final fi'ee Chloride content remained higher than the critical chloride tN~shold. The results of FT-IR technique showed that nitrites are likely washed out of concrete during immersion in chloride solution and phosphates interfere with the equilibrium between CO3 2 and HCO3" in concrete.The main conclusion of this study is: the efficiency of the tested inhibitors decreases with time, after two years of immersion in chloride solution. I~SUMI~ ffi'aetion des rayons" X (DRX) et la Spectroscopie Infi~arouge (IR). En milieu simulant le b~ton contamin~ par les chlorures, l'influence de l'inhibiteur sur la corrosion a ~t~ dvalu~e par (CP) et (SIE), Les r~sultats ~ obtenus ont montr~ que les pho~phat~ I N T R O D U C T I O NThe application of corrosion inhibitor is a technique for preventing steel corrosion in concrete exposed to chloride environments. Several papers have been published on the effectiveness of inhibitors mixed in fresh concrete [1][2][3][4][5][6]. This paper is a complement to previous works [7][8][9], which have shown the inhibiting effect of sodium phosphate and sodium nitrite tested in simulated concrete solutions.The efficiency of these two inhibitors was assessed by using steel...

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confidence: 72%

Studies on corrosion inhibition of steel reinforcement by phosphate and nitrite

et al. 2003

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“…Hope [38] summarized that the combination of calcium nitrite and sodium molibdate is more efficient than calcium nitrite alon in corrosion ressistance. Dhouibi et al [39] have examined the inhibition efficiency of sodium phosphate and sodium nitrite, and found that the sodium nitrite is not effective at all if its concentration is lower than that of the chloride ions but sodium phosphate is totally effective when its concentration equals the chloride concentration. Vashi and Desai [40] have studied the effect corrosion of zinc in hydrochloric acid containing hexamine at different inhibitor concentration and temperature.…”

Section: Mixed Inhibitorsmentioning

confidence: 99%

Corrosion of Reinforced Steel in Concrete and Its Control: An overview

Quraishi¹,

Nayak²,

Kumar³

et al. 2017

J Steel Struct Constr

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Reinforced concrete structures show a very good durability as it is capable of withstanding the different kind of environmental exposure. However, the main limitation of concrete, even of good quality, is that the penetration of chlorides, carbon dioxide (CO 2 ), moisture, etc., can cause the corrosion of reinforcement bars (rebars). Corrosion of structure can be reduced by proper monitoring and taking suitable control measures at the proper time interval. Detailed review of corrosion of reinforced steel in concrete and its control has been studied and are presented in this paper.

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“…Phosphates have been investigated as the corrosion inhibitors of steel in concrete in previous studies [8][9][10]. It has been confirmed that sodium phosphate (Na 3 PO 4 ) can prevent pitting corrosion of steel in the simulated concrete pore solution if its concentration is equal to the chloride concentration [9].…”

Section: Introductionmentioning

confidence: 98%

Electrochemical and analytical characterization of three corrosion inhibitors of steel in simulated concrete pore solutions

Shi

Sun

2012

Int J Miner Metall Mater

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Corrosion inhibitors for steel, such as sodium phosphate (Na 3 PO 4 ), sodium nitrite (NaNO 2 ), and benzotriazole (BTA), in simulated concrete pore solutions (saturated Ca(OH) 2 ) were investigated. Corrosion behaviors of steel in different solutions were studied by means of corrosion potential (E corr ), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP). A field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray analysis (EDXA) was used for observing the microstructures and morphology of corrosion products of steel. The results indicate that, compared with the commonly used nitrite-based inhibitors, Na 3 PO 4 is not a good inhibitor, while BTA may be a potentially effective inhibitor to prevent steel from corrosion in simulated concrete pore solutions.

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Electrochemical methods for evaluating inhibitors of steel corrosion in concrete

Cited by 29 publications

References 2 publications

Studies on corrosion inhibition of steel reinforcement by phosphate and nitrite

Studies on corrosion inhibition of steel reinforcement by phosphate and nitrite

Corrosion of Reinforced Steel in Concrete and Its Control: An overview

Electrochemical and analytical characterization of three corrosion inhibitors of steel in simulated concrete pore solutions

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