Effect of Superficial Oxides on Corrosion of Steel Reinforcement Embedded in Concrete

Avila-Mendoza, J.; Flores, José Martín Medina; Castillo, Ulysses

doi:10.5006/1.3293478

Cited by 32 publications

(13 citation statements)

References 2 publications

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“…This oxide/hydroxide layer, although electrochemically active, will not have the properties of the initially formed passive layer and cannot be considered as such. This must be the case as a growth of this deposit layer is not influencing the barrier (passive) layer i.e., the deposit layer, which becomes thicker with cycling, will not contribute to passivity, since a contribution to passivity would result in a delay of film growth [78]. This would mean that the layer formation at peak III for group R and the protected groups P is mainly relevant to oxidation of Fe 2R to Fe 3R instead of the formation from metallic iron.…”

Section: Region I -Hydrogen Evolution Reactionmentioning

confidence: 99%

“…As mentioned, after the first cycle there is initial drop in the anodic current at peak IIIa, which is probably associated with an attempt to repair the initially formed product layer and repassivation in the high alkaline medium of pH 12.6. Rust layers however (as in specimen C) in alkaline solutions, even without the presence of Cl À , may produce active corrosion on the steel surface [78][79][80]. Thus competing mechanisms of passivation and de-passivation are most likely responsible for the almost constantly high currents at anodic and cathodic peaks III and V in specimen C with cycling, since the rust interferes in some way with the passivation process.…”

Section: Region I -Hydrogen Evolution Reactionmentioning

confidence: 99%

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Electrochemical behavior of corroded and protected construction steel in cement extract

Koleva

2011

Materials & Corrosion

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The corrosion behavior of corroded, cathodically protected and control (reference) construction steel, previously embedded in concrete, was studied in cement extract (pH 12.6, considered as concrete pore water), using cyclic voltammetry (CVA) and potentiodynamic polarization (PDP). The necessity for this investigation occurred from the previously observed and commented discrepancies in the recorded corrosion parameters for corroded and protected steel in embedded conditions [1]. Therefore this study aimed to evaluate how the ''naturally'' formed in concrete product layers (after 460 days) will influence the electrochemical behavior of the steel in cement extract. The PDP measurements reveal the lowest corrosion resistance to be for the previously corroded steel samples, for which the most active corrosion potential (À0.7 V SCE) and the highest anodic current in the potential region 0 to 0.6 V (SCE) were recorded. The CVA tests support the results from PDP and correlate the properties of the naturally formed layers with the recorded peak current densities and peak potentials with cycling. For all specimens, except the corroded ones, the peak potential initially shifts anodically, which denotes for a high corrosion resistance in the former and low corrosion resistance in the latter case. For the control and protected specimens, the passive current in the potential region of 0 to 0.6 V (SCE) remains almost unchanged with cycling, i.e. the protective properties of the initial layers remain unchanged. Thickening of the film with cycling does not influence the corrosion resistance of the previously formed layers. For the protected specimens, however, a tendency to reach a steady state and change of peak currents' height only were observed, without a pronounced shift to more anodic values. An increase in the peak current only, not accompanied by anodic shift of the peak potential, suggests that the layers in the cathodically protected specimens are more homogeneous and compact. Overall it can be stated that in cement extract, the product layer with lowest corrosion resistance is the one on the surface of the corroded steel reinforcement. The product layers in the protected specimens (although similar to control conditions) are with the highest corrosion resistance.

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Section: Region I -Hydrogen Evolution Reactionmentioning

confidence: 99%

Section: Region I -Hydrogen Evolution Reactionmentioning

confidence: 99%

Electrochemical behavior of corroded and protected construction steel in cement extract

Koleva

2011

Materials & Corrosion

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“…The detrimental effect of corrosion on the service life of reinforced concrete structures induced the development of various research projects in different domains 7–17 including the description of electrochemical processes in reinforcing steel/concrete system, favourable corrosion conditions, transport mechanisms and kinetics of aggressive species, mechanical consequences, monitoring tools… Nevertheless, very few studies were dedicated to local analytical characterisations of the steel/concrete interface in these chlorinated environments, in relation with the electrochemical behaviour. This knowledge is of primary importance in view of mechanical modelling as each corrosion product presents different volume that will affect the expansion of the rebar/concrete interface during the corrosion process 18, 19.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of the steel concrete interface submitted to chloride‐induced‐corrosion

L’Hostis

Amblard

Guillot

et al. 2012

Materials & Corrosion

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International audienceThis paper deals with the characterisation by means of electrochemical, gravimetric and analytical methods of chloride-induced-corrosion behaviour of steel coupons embedded in chloride-containing-cement pastes. Corrosion rates were estimated from electrochemical measurements as well as gravimetric ones. They vary from 2.6 to 5.7 mm/year for 5 and 10 g/L chloride-containing-cement pastes. Analytical characterisations (including optical and electronical microscopy and Raman micro-spectroscopy) showed that corrosion patterns are not depending on the chloride content of the cement paste (5 and 10 g/L chloride in the interstitial solution). A localised corrosion pattern composed of pits growing inside the metallic substratum, a corrosion products layer (CPL) and a transformed medium (TM) was pointed out. CPL can be divided into two sub-layers (CPL1 and CPL2), characterised by the presence or absence of calcium coming from the cement matrix

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“…Novak et al (2001) reported that pre-rusted steel bars in concrete, even without any chloride content, shows technically unacceptable average corrosion rate. Mendoza et al (1994) also found a very high corrosion rate for the rusted steel bars. On the other hand, AlTayyib et al (1990) reported that the initial rusting does not have an adverse effect on the corrosion resistance of rebar embedded in concrete, which contradicts with the results obtained by Mendoza et al (1994) Novak et al (2001) and Li and Sagues (2001).…”

Section: Introductionmentioning

confidence: 90%

“…Mendoza et al (1994) also found a very high corrosion rate for the rusted steel bars. On the other hand, AlTayyib et al (1990) reported that the initial rusting does not have an adverse effect on the corrosion resistance of rebar embedded in concrete, which contradicts with the results obtained by Mendoza et al (1994) Novak et al (2001) and Li and Sagues (2001). Also, based on the accelerated laboratory investigations and long-term exposure tests in the marine environment, it was found that micro-structure of steel-concrete interface (physical adhesion, voids, etc.…”

Section: Introductionmentioning

confidence: 90%

Corrosion of Steel Bars in Concrete with the Variation of Microstructure of Steel-Concrete Interface

Mohammed

Hamada

Hasnat

et al. 2015

ACT

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An experimental investigation was carried out on chloride induced corrosion of steel bars in concrete under marine environment with the variation of micro-structure of steel-concrete interface. To create the variation of micro-structure of steel-concrete interface, steel bars coated with cement paste of different W/Cs and cement types were used. For investigation, cylindrical concrete specimens were made with steel bars (with and without cement paste coating). W/C ratios of cement paste coat were 0.3, 0.5, 0.7 and 1.0. The specimens were exposed to an accelerated seawater exposure controlled with automatic wetting and drying. The specimens were tested till 45 cycles in the exposure. Test items include compressive strength of concrete, chloride ingress into concrete, electrochemical evaluation of corrosion, microscopic investigations of steel-concrete interface by optical microscope, scanning electron microscope (SEM), and linear traverse. It is revealed that the initiation of corrosion is significantly influenced by the nature of micro-structure of the steelconcrete interface, such as size of voids at the steel-concrete interface.

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Effect of Superficial Oxides on Corrosion of Steel Reinforcement Embedded in Concrete

Cited by 32 publications

References 2 publications

Electrochemical behavior of corroded and protected construction steel in cement extract

Electrochemical behavior of corroded and protected construction steel in cement extract

Characterisation of the steel concrete interface submitted to chloride‐induced‐corrosion

Corrosion of Steel Bars in Concrete with the Variation of Microstructure of Steel-Concrete Interface

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