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Abstract

The corrosion behavior of reinforcing steel in concrete under dry-wet cycle condition has been studied by electrochemical noise(EN) compared with the electrochemical impedance spectroscopy(EIS),SEM micrographs and EDS.The statistical method has been employed to analyze the EN data of reinforcing steel in concrete,which revealed three different corrosion stages of reinforcing steel in concrete,including the dissolution of the passive film,the active corrosion and the cumulation of corrosion product.The wavelet transform has also been employed,which indicated that steel in concrete with pH 1 is associated with uniform corrosion,while steel in concrete with pH 3 and pH 7 are associated with localized corrosion,such as pitting corrosion.From the analysis of the shot noise theory,it was found that pitting corrosion is enhanced in pH 1 solution.Electrochemical impedance spectroscopy(EIS) also indicated that there were three corrosion stages of reinforcing steel in concrete.During the first stage,the spectrum consists of two capacitive loops,indicating that the reinforced concrete system contained two time constants.The first loop in the high frequency region was related to the capacitance and resistance of the concrete,while the second capacitive loop in the low frequency corresponding to the steel-concrete interface;during the second stage,there are three capacitive loops in the spectrum,the second capacitive loop in the intermediate frequency region should be ascribed to the rust layer of the steel;during the third stage,due to the diffusion of the corrosion product,the diameter of the semi-circles in the intermediate frequency region begins to decrease,especially in pH 1 system,it drops to very low value.

Keywords

steel, concrete, electrochemical noise, electrochemical impedance spectroscopy

Publication Date

2010-11-28

Online Available Date

2010-11-28

Revised Date

2010-11-28

Received Date

2010-11-28

References

[1]Zhao B,Li J H,Hu R G,et al.Study on the corrosionbehavior of reinforcing steel in cement mortar by electro-chemical noise measurements[J].Electrochimica Acta,2007,52:3976-3984.
[2]Tullmin M,Hansson C M.Electrochemical noise meas-urements on carbon and stainless steel reinforcing steels[J].Corrosion,1998:372.
[3]Mariaca L,Bautista A,Rodriguez P,et al.Use of electro-chemical noise for studying the rate of corrosion of rein-forcements embedded in concrete[J].Materials andStructures,1997,30:613-617.
[4]Legat A,Leban M,Bajt Z.Corrosion processes of steel inconcrete characterized by means of electrochemicalnoise[J].Electrochimica Acta,2004,49:2741-2751.
[5]Sanchez-Amaya J M,Cottis R A,Botana F J.Shot noiseand statistical parameters for the estimation of corrosionmechanisms[J].Corrosion Science,2005,47:3280-3299.
[6]Cao F H,Zhang Z,Su J X,et al.Electrochemical noiseanalysis of Ly12-T3 in Exco solution by discrete wavelettransform technique[J].Electrochimica Acta,2006,51:1359-1364.
[7]Cai C,Zhang Z,Cao F H,et al.Analysis of pitting corro-sion behavior of pure Al in sodium chloride solution withthe wavelet technique[J].Journal of ElectroanalyticalChemistry,2005,578:143-150.
[8]Zhang Z,Leng W H,Cai Q Y,et al.Study of the zinc e-lectroplating process using electrochemical noise tech-nique[J].Journal of Electroanalytical Chemistry,2005,578:357-367.
[9]Aballe A,Bethencourt M,Botana F J,et al.Using wave-lets transform in the analysis of electrochemical noisedata[J].Electrochimica Acta,1999,44:4805-4816.
[10]Aballe A,Bethencourt M,Botana F J,et al.Wavelettransform-based analysis for electrochemical noise[J].Electrochemistry Communications,1999,1:266-270.
[11]Al-Mazeedi H A A,Cottis R A.A practical evaluationof electrochemical noise parameters as indicators ofcorrosion type[J].Electrochimica Acta,2004,49:2787-2793.
[12]Puget Y,Trethewey K,Wood R J K.Electrochemicalnoise analysis of polyurethane-coated steel subjectedto erosion-corrosion[J].Wear,1999,233-235:552-567.
[13]Na K-H,Pyun S-I.Effect of sulphate and molybdate i-ons on pitting corrosion of aluminium by using electro-chemical noise analysis[J].Journal of Electroanalyti-cal Chemistry,2006,596:7-12.

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