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. 2015 Dec 24;16(1):15.
doi: 10.3390/s16010015.

Corrosion Assessment of Steel Bars Used in Reinforced Concrete Structures by Means of Eddy Current Testing

Naasson P de Alcantara Jr  1 , Felipe M da Silva  2 , Mateus T Guimarães  3 , Matheus D Pereira  4
Affiliations

Corrosion Assessment of Steel Bars Used in Reinforced Concrete Structures by Means of Eddy Current Testing

Naasson P de Alcantara Jr et al. Sensors (Basel). .

Abstract

This paper presents a theoretical and experimental study on the use of Eddy Current Testing (ECT) to evaluate corrosion processes in steel bars used in reinforced concrete structures. The paper presents the mathematical basis of the ECT sensor built by the authors; followed by a finite element analysis. The results obtained in the simulations are compared with those obtained in experimental tests performed by the authors. Effective resistances and inductances; voltage drops and phase angles of wound coil are calculated using both; simulated and experimental data; and demonstrate a strong correlation. The production of samples of corroded steel bars; by using an impressed current technique is also presented. The authors performed experimental tests in the laboratory using handmade sensors; and the corroded samples. In the tests four gauges; with five levels of loss-of-mass references for each one were used. The results are analyzed in the light of the loss-of-mass and show a strong linear behavior for the analyzed parameters. The conclusions emphasize the feasibility of the proposed technique and highlight opportunities for future works.

Keywords: accelerated corrosion techniques; corrosion process; eddy current testing; nondestructive testing; reinforced concrete structures.

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Figures

Figure 1
Figure 1
Schematic illustration of the various steps of the concrete deterioration due to the corrosion of the reinforcement (adapted from [3]).
Figure 2
Figure 2
The electrical equivalent circuit of the ECT sensor for reinforcement inspections.
Figure 3
Figure 3
Simulation of the flux distribution under an ECT sensor. (a) Without the steel bar; (b) With the steel bar; (c) Details of the flux in the steel bar and region around it.
Figure 4
Figure 4
The electromagnetic components of an ECT sensor to inspect the reinforcement of concrete structures. (a) Perspective view; (b) Coil dimensions.
Figure 5
Figure 5
Magnetic flux density at the surface of the coil and the steel bar.
Figure 6
Figure 6
Induced current in the steel bar represented by the red arrows. (a) Perspective view; (b) Top view; (c) side view.
Figure 7
Figure 7
Simulated (color marks) and experimental results (hollow black marks) for the effective resistance (a); effective inductance (b); voltage (c); and phase angle (d) for a 20 mm steel bar. Red marks: Steel bar placed 25 mm under the sensor. Blue marks: Steel bar placed 45 mm under the sensor.
Figure 7
Figure 7
Simulated (color marks) and experimental results (hollow black marks) for the effective resistance (a); effective inductance (b); voltage (c); and phase angle (d) for a 20 mm steel bar. Red marks: Steel bar placed 25 mm under the sensor. Blue marks: Steel bar placed 45 mm under the sensor.
Figure 8
Figure 8
Schematic arrangement for the corrosion process.
Figure 9
Figure 9
Four concrete samples in the process of corrosion, at the laboratory.
Figure 10
Figure 10
(a) Concrete debris; (b) Samples of corroded steel bars.
Figure 11
Figure 11
(a) An ECT sensor for corrosion inspection; (b) Experimental setup for the measurements.
Figure 12
Figure 12
Schematic representation of the movement of the sensor: (a) top view; (b) side view.
Figure 13
Figure 13
Measured voltage at the capacitive array for corroded (loss of mass equal zero) and non-corroded steel bars, as a function of the distance of the bar to the sensor. Red curves—20.0 mm bar gauge; Blue curves—16.0 mm bar gauge, magenta curves—12.5 mm bar gauge; and black curves—10.0 mm bar gauge.
Figure 14
Figure 14
Voltage difference, as a function of the bar gauge, loss of mass and reference distance. Red curves—20 mm bar gauge; Blue curves—16.0 mm bar gauge; magenta curves—12.5 mm bar gauge; and black curves—10.0 mm bar gauge.
Figure 15
Figure 15
Resistance (a) and inductance (b) for the steel bars at the reference distance of 5 mm.
Figure 16
Figure 16
Resistance (a) and inductance (b) for the steel bars at the reference distance of 25 mm.
Figure 17
Figure 17
Resistance (a) and inductance (b) for the steel bars at the reference distance of 45 mm.
Figure 18
Figure 18
Lift-off effects on the resistance values. (a) absolute values; (b) Percent variation.
Figure 19
Figure 19
Lift-off effects on the inductance values. (a) absolute values; (b) Percent variation.
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References

    1. El Maaddawy T.A., Soudky K.A. Effectiveness of impressed current techniques to simulate corrosion of steel reinforcement in concrete. J. Mater. Civil Eng. 2003;15:41–47. doi: 10.1061/(ASCE)0899-1561(2003)15:1(41). - DOI
    1. Maruya T., Takeda H., Horiguchi K., Koyama S., Hsu K.L. Simulation of Steel Corrosion in Concrete Based on the Model of Macro-Cell Corrosion Circuit. J. Adv. Concrete Technol. 2007;6:343–362. doi: 10.3151/jact.5.343. - DOI
    1. Roqueta G., Jofre L., Feng M.Q. Analysis of the Electromagnetic Signature of Reinforced Concrete Structures for Nondestructive Evaluation of Corrosion Damage. IEEE Trans. Instrum. Meas. 2012;61:1090–1098. doi: 10.1109/TIM.2011.2174106. - DOI
    1. Arndt R., Jalinoos F. NDE for corrosion dectection in reinforced concrete structures—A benchmark approach; Proceedings of Non-Destructive Testing in Civil Engineering (NDTCE’09); Nantes, France. 30 June–3 July 2009; pp. 1–6.
    1. Erdogdu S., Kondratova I.L., Bremner T.W. Determination of Chloride Diffusion Coefficient of Concrete Using Open-Circuit Potential Measurements. Cem. Concr. Res. 2004;34:603–609. doi: 10.1016/j.cemconres.2003.09.024. - DOI

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