Electrochemical Impedance Analysis of Corrosion of Reinforcing Bars in Concrete

Abstract

Owing to the presence of loops related to the time constants originating from the structure and interfacial reactions, it is difficult to select a suitable equivalent circuit for curve fitting of the impedance spectrum of reinforced concrete. To investigate the time constants observed in the impedance spectrum of reinforced concrete and propose an appropriate equivalent circuit, electrochemical impedance measurements of reinforced concrete with different cover thicknesses were performed using a two-electrode system. In this case, two parallel reinforcing bars were embedded in the concrete, and a cyclic wet-dry test was conducted to accelerate the corrosion of the reinforcing bars. It was confirmed that part of the large loop in the low-frequency range was related to the reinforcing bar/ concrete interface, a distorted loop in the middle-frequency range was associated with rust formation on the reinforcing bars, and the small loop in the high-frequency range was attributed to the water distribution and pore structure in concrete.

Steel Corrosion Behavior of Reinforced Calcium Aluminate Cement-Mineral Additions Modified Mortar

“…In order to quantitatively analyze the microstructure of the CAC mortar and the electrochemical characteristics of the steel reinforcement during the corrosion process, the ZSimpWin software program ( accessed on 15 July 2021) was used to provide the equivalent circuit model for analyzing the EIS data. After comprehensively comparing the fitting effects of various classical equivalent circuit models [ 21 , 22 , 23 , 24 , 25 ], the model R s ( Q c R c )( Q dl ( R ct W )) was used to fit the impedance spectroscopy of the reinforced CAC mortar for chloride ion attack.…”

Corrosion Inhibition for Steel Surface Using a Polyacrylic Gel Sheet Containing Ni–Al Layered Double Hydroxide Prepared by Liquid-Phase Deposition

“…Among the various electrochemical measurement methods for corrosion monitoring and evaluation of the corrosion preventive performance of rust inhibitors, [42][43][44][45][46] this study analyzed the corrosion current using the simplest polarization measurement. Polarization measurements were performed using the gel sheet, and the corrosion-inhibition effect was examined by determining the corrosion potential and corrosion current by the Tafel extrapolation method from the obtained plots.…”

“…proportional to the corrosion current density, it is generally considered that suppressing the corrosion current density leads to corrosion protection for metal surfaces. 6,42 3. Results and discussion Figure 1 shows the SEM image of the prepared Ni-Al LDH deposited on a steel plate and fumed alumina by the LPD process.…”

Evaluation of Corrosion Progress Using Multichannel Iron Wire Electrodes Embedded in a Cement Test Block

“…The impedance measurement is also useful because it provides considerable information on the passive/corroding states and corrosion rate of reinforcing bars. [21][22][23][24][25][26][27][28][29] Therefore, the impedance method has been used to evaluate the progress of corrosion due to neutralization, 25,30) salt concentration, 21,27,29) and the effect of dry and wet conditions 21,22,26) and cover thickness 29) on reinforcing bar. In order to understand the corrosion progress of reinforcing bars in a concrete structure, an investigation of the transition of the corrosion environment in the cement block, the corrosion transition of the reinforcing bars as a function of the depth from the surface, and the corrosion mechanism is essential.…”