Advances in Electrochemical Impedance Measurements in Reinforced Concrete

Andrade, Carmen; Soler, L.; Nóvoa, X.R.

doi:10.4028/www.scientific.net/msf.192-194.843

Cited by 42 publications

(20 citation statements)

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“…The Polarization Resistance may also be obtained from Electrochemical Impedance techniques, [30][31][32][33][34][35][36][37][38][39]. It is not the aim of the present Recommendation to describe the procedure because its application to on-site measurements proves to be very complex.…”

Section: Basic Aspectsmentioning

confidence: 99%

Test methods for on-site corrosion rate measurement of steel reinforcement in concrete by means of the polarization resistance method

Andrade¹,

Alonso²

2004

Mat. Struct.

457

241

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SCOPEThis Recommendation covers the description of nondestructive electrochemical test methods for the estimation in large size concrete structures of the instantaneous corrosion current density, ioorr, expressed in gA/cm 2, by means of the so-called Polarization Resistance technique, R o, in order to assess the condition of embedded steel reinforcement related to its corrosion.The values of i~orr, Can be used to assess the rate of degradation of concrete structures affected by reinforcement corrosion. However, they cannot give information on the actual loss in steel cross section which, at present, only can be assessed by means of direct visual observation.Values of the free corrosion potential or half-cell potential, Ecorr [V], of the embedded reinforcing steel and of the electrical concrete resistance, Re [f)], are obtained as preliminary steps of the Rp measurements. Values of the concrete resistivity, P [~m], can be calculated from Re values providing the geometrical arrangement of the electrodes enables this calculation.Both parameters, Ecorr and Re (or P) may be used to complement the reliability of the ico~r measurements. SIGNIFICANCE AND USEThe test methods described in the present Recommendation are suitable for on-site condition assessment of steel reinforced concrete structures.The methods can be applied regardless of the thickness of concrete cover and the rebar size or detailing. However, when the bars are electrically connected, only the corrosion of the closer layer of reinforcements facing the counter electrode, CE, can be measured. This closer reinforcement layer practically shields the penetration of the polarizing current to deeper lying reinforcements. When rebars are electrically isolated, the steel bar connected to the instrument will be measured irrespective of its depth (depths higher than 1 m have been tested).The test methods can be used at any time during the service life of the structure, and in any kind of climate, providing the temperature is higher than 0~ A very dry concrete surface of P > 1000 f~m makes the measurement difficult. Some prewetting of the concrete surface is always necessary.The Icorr results obtained by the test methods can be used for one of the following purposes:1359-5997/04 9 RILEM 623 RILEM TC 154-EMC 1) To assess the present corrosion condition of the reinforcement, that is, to discriminate between corroding and non-corroding (passivated) zones. 2) To evaluate the effectivity of a repair work. 3) To calculate the loss in rebar cross section by means of integration of Ir during the propagation period (providing the initiation time is known). This calculation enables the Lo~r values to be implemented into structural models in order to assess the further development of the structural performance with respect to cover cracking, loss of bond and loss of load-bearing capacity.The corrosion current values in addition to the measurements of the corrosion potential, Er and of the concrete resistivity, P, may be complemented by other data from the concrete: rebar diame...

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Section: Basic Aspectsmentioning

confidence: 99%

Test methods for on-site corrosion rate measurement of steel reinforcement in concrete by means of the polarization resistance method

Andrade¹,

Alonso²

2004

Mat. Struct.

457

241

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“…The low frequency region (lower than 10 Hz) are related to the Faradaic corrosion process occurring on the embedded steel electrodes [14] .…”

Section: Resultsmentioning

confidence: 99%

Electrochemical behavior of steel bar in electrolytes: Influence of pH value and cations

Qin

Jiang

Chu

et al. 2011

J. Wuhan Univ. Technol.-Mat. Sci. Edit.

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Steel bar corrosion on electrolytes and the influence of cation were investigated. Three electrolytes of Ca(OH) 2 , NaOH and KOH with pH levels of 12.5, 11.5, 10.5, 9.5, 8.5 were prepared, meanwhile, the methods of free corrosion potential and electrochemical impedance spectra (EIS) were used to evaluate the infl uence of cations on the depassivation of the steel bar in electrolytes. The experimental results indicate that the initial corrosion pH value of the steel bar is infl uenced by the cation in electrolyte and the infl uence of K + in electrolyte is the most remarkable, followed by Na + and Ca 2+ . The initial corrosion pH values are 10.5 in KOH electrolyte, 9.5 in NaOH electrolyte and lower than 8.5 in Ca(OH) 2 electrolyte.

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“…[12] The high-frequency domain can provide information on the microstructure of the concrete cover. [13] Materials and methods…”

Section: Introductionmentioning

confidence: 99%

Microstructural changes in a cementitious membrane due to the application of a DC electric field

Covelo

Díaz

Freire

et al. 2008

Journal of Environmental Science and Health, Part A

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The use of electromigration techniques to accelerate chloride ions motion is commonly employed to characterise the permeability of cementitious samples to chlorides, a relevant parameter in reinforced concrete corrosion. This paper is devoted to the study of microstructure's changes occurring in mortar samples when submitted to natural diffusion and migration experiments. The application of an electric field reduces testing time in about one order of magnitude with respect to natural diffusion experiments. Nevertheless, the final sample's microstructure differs in both tests. Impedance Spectroscopy is employed for real time monitoring of microstructural changes. During migration experiments the global impedance undergoes important increase in shorter period of time compared to natural diffusion tests. So, the forced motion of ions through the concrete membrane induces significant variations in the porous structure, as confirmed by Mercury Intrusion Porosimetry. After migration experiments, an important increase in the capillary pore size (10-100 nm) was detected. Conversely, no relevant variations are found after natural diffusion tests. Results presented in this work cast doubt on the significance of diffusion coefficient values obtained under accelerated conditions.

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Advances in Electrochemical Impedance Measurements in Reinforced Concrete

Cited by 42 publications

References 0 publications

Test methods for on-site corrosion rate measurement of steel reinforcement in concrete by means of the polarization resistance method

Test methods for on-site corrosion rate measurement of steel reinforcement in concrete by means of the polarization resistance method

Electrochemical behavior of steel bar in electrolytes: Influence of pH value and cations

Microstructural changes in a cementitious membrane due to the application of a DC electric field

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