Corrosion of Steel Rebars in Anoxic Environments. Part I: Electrochemical Measurements

The number of reinforced concrete structures subject to anoxic conditions such as offshore platforms and geological storage facilities is growing steadily. This study explored the behaviour of embedded steel reinforcement corrosion under anoxic conditions in the presence of different chloride concentrations. Corrosion rate values were obtained by three electrochemical techniques: Linear polarization resistance, electrochemical impedance spectroscopy, and chronopotenciometry. The corrosion rate ceiling observed was 0.98 µA/cm2, irrespective of the chloride content in the concrete. By means of an Evans diagram, it was possible to estimate the value of the cathodic Tafel constant (bc) to be 180 mV dec−1, and the current limit yielded an ilim value of 0.98 µA/cm2. On the other hand, the corrosion potential would lie most likely in the −900 mVAg/AgCl to −1000 mVAg/AgCl range, whilst the bounds for the most probable corrosion rate were 0.61 µA/cm2 to 0.22 µA/cm2. The experiments conducted revealed clear evidence of corrosion-induced pitting that will be assessed in subsequent research.

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Corrosion of Steel Rebars in Anoxic Environments. Part II: Pit Growth Rate and Mechanical Strength

Materials ◽

10.3390/ma14102547 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2547

Author(s):

Elena Garcia ◽

Julio Torres ◽

Nuria Rebolledo ◽

Raul Arrabal ◽

Javier Sanchez

Keyword(s):

Mechanical Strength ◽

Chloride Content ◽

Element Model ◽

Offshore Structures ◽

Anoxic Environments ◽

Electrochemical Parameters ◽

Cathode Area ◽

Optical Profilometer ◽

Set Up ◽

Corrosion Of Steel

Reinforced concrete may corrode in anoxic environments such as offshore structures. Under such conditions the reinforcement fails to passivate completely, irrespective of chloride content, and the corrosion taking place locally induces the growth of discrete pits. This study characterised such pits and simulated their growth from experimentally determined electrochemical parameters. Pit morphology was assessed with an optical profilometer. A finite element model was developed to simulate pit growth based on electrochemical parameters for different cathode areas. The model was able to predict long-term pit growth by deformed geometry set up. Simulations showed that pit growth-related corrosion tends to maximise as cathode area declines, which lower the pitting factor. The mechanical strength developed by the passive and prestressed rebar throughout its service life was also estimated. Passive rebar strength may drop by nearly 20% over 100 years, whilst in the presence of cracking from the base of the pit steel strength may decline by over 40%.

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Effect of Migrating Corrosion Inhibitor on Corrosion Rate of Reinforcing Steel in Concrete with Various Admixed Chloride

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.3146 ◽

2012 ◽

Vol 204-208 ◽

pp. 3146-3150 ◽

Cited By ~ 1

Author(s):

Zhi Yong Liu ◽

Xin Gang Zhou ◽

Xiu Lin Li

Keyword(s):

Corrosion Rate ◽

Electrochemical Impedance ◽

Corrosion Current ◽

Cementitious Materials ◽

Steel Bar ◽

Average Corrosion Rate ◽

Corrosion Of Steel ◽

High Chloride ◽

Effect Of Surface ◽

Chloride Contaminated

Effect of surface applied inhibitor on the durability of chloride contaminated reinforced concrete has been investigated in this paper. The C30 concrete samples contaminated with 0.5%,1.0%,1.5% NaCl by mass of the cementitious materials in the mixing process were experienced adequate curing and subjected to 1 months exposure tests after painting with 400 g/m2 MCIs. The corrosion behavior of the steel rebar in concrete samples was monitored by using electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and corrosion currents. The results indicate that, after painting the MCIs for 28d on the surface of concrete samples with 0.5% and 1% NaCl, the average corrosion rate of reinforcements in concrete samples （0.34μA/cm2 ）is lower than that of the control one (No.0, no painted inhibitor), and about 1/4 of the initial corrosion current of the samples with 0.5% and 1% NaCl before painting MCI. But the corrosion current of rebar in No.3 sample with 1.5% NaCl is still higher than that of the control one (No.0). Therefore, painting MCIs on the surface of samples is very effective to inhibit the corrosion of steel bar in concrete at low or middle chloride conditions, but it is not enough to repair severely corroded steel bar in high chloride contaminated concrete.

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Corrosion Behavior of Al-Sn-Bi Alloys in Ethylene Glycol-Water Mixtures

CORROSION ◽

10.5006/0010-9312-68.5.421 ◽

2012 ◽

Vol 68 (5) ◽

pp. 421-431

Author(s):

J.L. Gama-Ferrer ◽

J.G. Gonzalez-Rodriguez ◽

I. Rosales ◽

J. Uruchurtu

Keyword(s):

Electrochemical Impedance Spectroscopy ◽

Impedance Spectroscopy ◽

Corrosion Rate ◽

Ethylene Glycol ◽

Corrosion Behavior ◽

Potentiodynamic Polarization ◽

Electrochemical Noise ◽

Electrochemical Impedance ◽

Electrochemical Techniques ◽

Potentiodynamic Polarization Curves

A study of the effect of Sn (1, 2, 3.5, 4.5, and 5 wt%) and Bi (0.5, 1.5, 3, and 4%) on the corrosion behavior of Al in ethylene glycol (C2H6O2)-40% water mixtures at 20, 40, and 60°C has been carried out using electrochemical techniques. Techniques include potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and electrochemical noise (EN) measurements. The three techniques have shown that additions of either Sn or Bi contents increased the corrosion rate of pure Al in all cases, and that generally speaking, the corrosion rate increased by increasing the temperature except for the alloy containing 1% Sn + 4% Bi, which showed the lowest corrosion rate at 60°C. This was because of a galvanic effect from the presence of Sn and/or Bi particles on the surface alloy, which acted as local cathodes, leading to an acceleration of corrosion. Nyquist diagrams showed two semicircles at 20°C and only one at 40°C or 60°C for all the alloys, showing two different corrosion-controlling mechanisms. EN measurements showed evidence of a mixture of both localized and uniform types of corrosion for all Al-based alloys.

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Electrochemical Study of the Protective Characteristics of CO2 Corrosion Product Layers for Steels API X80 and P110

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.830.139 ◽

2016 ◽

Vol 830 ◽

pp. 139-146

Author(s):

Andrea H. Rojas ◽

Adriana Forero Ballesteros ◽

I.S. Bott

Keyword(s):

Corrosion Rate ◽

Corrosion Product ◽

Oil And Gas ◽

Electrochemical Impedance ◽

Electrochemical Techniques ◽

Morphological Characterization ◽

Product Layer ◽

X Ray Diffraction ◽

Energy Dispersion Spectroscopy ◽

Different Temperatures

This work evaluate the protective characteristic of the CO2 corrosion product layers formed on the surface of two types of steels, API 5L X80 used for transportation of oil and gas, and API 5CT P110 used for case tubing and pipe for oil drilling.Electrochemistry evaluations and morphological characterization of the obtained layer were performed. These steels were exposed to a brine solution containing 3% wt of NaCl, in a pressurized autoclave with 55 bar of CO2 and total pressure of 75 bar at different temperatures (25, 50 and 75°C) and immersion times (7, 15, 21 and 30 days). The corrosion rate was determined by mass loss tests and electrochemical techniques, such as Linear Polarization Resistance and Electrochemical Impedance Spectroscopy. Characteristics of the corrosion product layer such as thickness, morphology, and chemical composition were analyzed by scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS) and X-Ray diffraction (XRD). The corrosion rate decreases with the increase of the immersion time and temperature, and the lower rate of corrosion was obtained for 75°C after 30 days of immersion, for both steels

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Evaluation of Corrosion Rate of Steel Rebars Embedded in Mortar Mixed with Triturated Tire Particles

MRS Proceedings ◽

10.1557/opl.2013.1128 ◽

2013 ◽

Vol 1612 ◽

Author(s):

Claudia Berenice Flores Valdez ◽

Francisco G. Pérez-Gutiérrez ◽

Imelda Esparza Álvarez ◽

Orlando Guarneros García ◽

Sandra Luz Rodríguez Reyna

Keyword(s):

Corrosion Rate ◽

Mercury Intrusion Porosimetry ◽

Electrochemical Techniques ◽

Chloride Ion ◽

Environmental Benefit ◽

Ion Diffusion ◽

Material Recycling ◽

Test Pieces ◽

Steel Rebars ◽

Chloride Ion Diffusion

ABSTRACTDifferent materials, such as triturated waste tire (WT) particles, have been proposed as aggregate to improve mortar properties and reduce its cost in recent years. Using WT as aggregate implies material recycling, providing an environmental benefit. Previous studies show controversy on the chloride ion diffusion coefficient in mortar test specimens as a function of the WT content. The objective of this investigation is to evaluate the corrosion rate of steel reinforcement embedded in mortar specimens using WT as aggregate when exposed to chlorides. Electrochemical techniques, mercury intrusion porosimetry and scanning electron microscope were used to measure corrosion rate, porosity and microstructure of mortar matrix, respectively. Corrosion rate and porosimetry results were found to directly correlate for test pieces with 7.5% of WT compared with control samples and test pieces containing 5%, 10% of WT; such results are supported by visual inspection of steel reinforcements. Our results show that substituting 7.5% of sand with WT when preparing mortar provides the optimum protection.

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Adsorption Studies of the Effect of Thiosemicarbazides on the Corrosion of Steel in Phosphoric Acid

Adsorption Science & Technology ◽

10.1260/0263617001493378 ◽

2000 ◽

Vol 18 (3) ◽

pp. 177-194 ◽

Cited By ~ 34

Author(s):

M.A. Ameer ◽

E. Khamis ◽

G. Al-Senani

Keyword(s):

Phosphoric Acid ◽

Active Sites ◽

Electrochemical Impedance ◽

Electrochemical Techniques ◽

Molecular Structures ◽

Active Centre ◽

Inhibitor Molecule ◽

Thiosemicarbazide Derivatives ◽

Experimental Findings ◽

Corrosion Of Steel

The corrosion inhibition of steel in phosphoric acid by thiosemicarbazide derivatives has been studied using different chemical and electrochemical techniques. The observed order of increasing inhibition efficiency was correlated with changes in the molecular structures of the inhibitors. Potentiodynamic polarization curves indicate that the compounds are mixed-type inhibitors. Electrochemical impedance spectroscopy has been used successfully to evaluate the performance of the inhibitors. AC measurements showed that the dissolution process was activation-controlled. The kinetic–thermodynamic model and the Flory–Huggins adsorption isotherm described the experimental findings well. The number of active sites, binding constant and change in free energy were computed for all the inhibitors studied. It was found that the inhibitor molecule was adsorbed through more than one active centre and occupied more than one active site on the steel surface.

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The Inhibitive Effect of 2-Phenyl-3-nitroso-imidazo [1, 2-a]pyridine on the Corrosion of Steel in 0.5 M HCl Acid Solution

E-Journal of Chemistry ◽

10.1155/2010/525606 ◽

2010 ◽

Vol 7 (s1) ◽

pp. S35-S42 ◽

Cited By ~ 5

Author(s):

K. Bouhrira ◽

F. Ouahiba ◽

D. Zerouali ◽

B. Hammouti ◽

M. Zertoubi ◽

...

Keyword(s):

Carbon Steel ◽

Steel Surface ◽

Inhibition Efficiency ◽

Electrochemical Impedance ◽

Electrochemical Techniques ◽

Carbon Steel Surface ◽

Langmuir Isotherm Model ◽

Corrosion Of Steel ◽

Good Agreement

The effect of 2-phenyl-3-nitroso-imidazo[1,2-a]pyridine (PNIP) on the corrosion inhibition of carbon-steel in 0.5 M HCl was studied by weight loss and different electrochemical techniques such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization. The obtained results showed that PNIP effectively reduces the corrosion rate of carbon steel. Inhibition efficiency (E%) increases with inhibitor concentration to attain 88% at 10-3M. Adsorption of that PNIP on the carbon steel surface in 0.5 M HCl follows the Langmuir isotherm model. E% values obtained from various methods used are in good agreement. SEM characterization of the steel surface is made.

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Effect of Surface Applied Inhibitor on Corrosion Rate of Steel Bar in High Strength Concrete with Various Admixed Chlorides

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.174-177.1184 ◽

2012 ◽

Vol 174-177 ◽

pp. 1184-1187 ◽

Cited By ~ 1

Author(s):

Wen Jian Lan ◽

Baohong Wu ◽

Zhi Yong Liu

Keyword(s):

Corrosion Rate ◽

High Strength Concrete ◽

Electrochemical Impedance ◽

High Strength ◽

Chloride Content ◽

Corrosion Current ◽

Cementitious Materials ◽

Strength Concrete ◽

Average Corrosion Rate ◽

Effect Of Surface

Effect of surface applied inhibitor on the durability of high strength reinforced concrete with various chloride content has been investigated in this paper. The C60 concrete specimens contaminated with 0.5%,1.0%,1.5% NaCl by mass of the cementitious materials were prepared and experienced in months exposure tests after painting with 400 g/m2 inhibitor. The electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) of the steel rebar in specimens was tested. The results indicate that after surface painting the inhibitor for 28d the bars in concrete specimens with 0.5% NaCl and bar with 25mm cover in specimen with 1% NaCl show the average corrosion rate lower than that of control one (No.0, no painted inhibitor). While the corrosion current of rebar (38mm cover) for No.2 specimen with 1% NaCl and bars for No.3 specimen with 1.5% NaCl are still higher than that of the control one (No.0). The results indicate that the surface painted inhibitor on C60 concrete are effective to inhibit the corrosion of bar concrete at low or middle chloride conditions and not enough to repair the bars in high chloride contaminated concrete. The lower organic nitrogen content in 40-50mm depth also indicates that the inhibitor is harder to penetrate into deeper parts of high strength concrete compared with low or middle grade concrete.

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Quantitative Non-Linear Effect of High Ambient Temperature on Chloride Threshold Value for Steel Reinforcement Corrosion in Concrete under Extreme Boundary Conditions

Materials ◽

10.3390/ma14247595 ◽

2021 ◽

Vol 14 (24) ◽

pp. 7595

Author(s):

Abdulrahman M. Alhozaimy ◽

Mshtaq Ahmed ◽

Raja Rizwan Hussain ◽

Abdulaziz Al-Negheimish

Keyword(s):

Corrosion Rate ◽

Corrosion Potential ◽

Electrochemical Techniques ◽

Chloride Content ◽

Threshold Value ◽

Chloride Ions ◽

Water Soluble ◽

Linear Effect ◽

Chloride Threshold ◽

Exposure Temperature

This paper investigates the effect of high ambient temperatures on the chloride threshold value for reinforced concrete (RC) structures. Two commonly available carbon steel rebars were investigated under four different exposure temperatures (20 °C (68 °F), 35 °C (95 °F), 50 °C (122 °F), and 65 °C (149 °C)) using environmental chambers at a constant relative humidity of 80%. For each temperature, six different levels of added chloride ions (0.00%, 0.15%, 0.30%, 0.60%, 0.90%, and 1.20% by weight of cement) were used to study the chloride threshold value. Corrosion initiation was detected by monitoring the corrosion potential and corrosion rate using electrochemical techniques. The water-soluble (free) and acid-soluble (total) chlorides were determined using potentiometric titration according to the relevant ASTM standards. The threshold chloride content for each exposure temperature was determined by analyzing the corrosion potential, corrosion rate, and chloride content of each specimen. The results showed that the chloride threshold values were significantly temperature-dependent. At temperatures of 20 °C (68 °F) and 35 °C (95 °F), the chloride threshold value (expressed as free chlorides) was approximately 0.95% by weight of cement. However, as the temperature increased to 50 °C (122 °F), the chloride threshold decreased significantly to approximately 0.70% by weight of cement. The reduction in the chloride threshold value became more dramatic at an exposure temperature of 65 °C (149 °F), decreasing to approximately 0.25% by weight of cement. The trends were similar for the rebars from the two sources, indicating that the rebar source had little influence on the chloride threshold value.

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Corrosion Behavior of Fe40Al Alloy with Additions of Ti, Ag, and Cr in Molten KCl +ZnCl2

International Journal of Corrosion ◽

10.1155/2012/146486 ◽

2012 ◽

Vol 2012 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

R. Ademar ◽

J. G. Gonzalez-Rodriguez ◽

J. Uruchurtu ◽

J. Porcayo-Calderon ◽

V. M. Salinas-Bravo ◽

...

Keyword(s):

Corrosion Rate ◽

Corrosion Behavior ◽

Electrochemical Impedance ◽

Electrochemical Techniques ◽

Intermetallic Alloy ◽

Corrosion Performance ◽

Linear Polarization Resistance ◽

Potentiodynamic Polarization Curves ◽

Eis Measurements ◽

The Stability

The effect of 2.5 at.% Cr, Ti, and Ag on the corrosion behavior of Fe40Al intermetallic alloy in KCl-ZnCl2(1 : 1 M) at 670°C has been evaluated by using electrochemical techniques. Techniques included potentiodynamic polarization curves, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) measurements. Results have shown that additions of both Cr and Ti were beneficial to the alloy, since they decreased its corrosion rate, whereas additions of Ag was detrimental, since its additions increased the corrosion rate, although the alloy was passivated by adding Ag or Cr. The best corrosion performance was obtained with the addition of Cr, whereas the highest corrosion rate was obtained by adding Ag. This is explained in terms of the stability of the corrosion products formed film.

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