Macrocell corrosion in carbonated Portland and Portland-fly ash concrete - Contribution and mechanism

Revert, Andrés Belda; Hornbostel, Karla; Weerdt, Klaartje De

doi:10.1016/j.cemconres.2018.12.005

Cited by 25 publications

(11 citation statements)

References 17 publications

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“…Concerning the effect of macrocells in carbonation-induced corrosion, fewer studies are available. Figure 9 summarizes the results from three laboratory studies [48,49,53]. These studies indicate that macro-cell formation can raise the corrosion rate, generally by 50 to 250% for cathode/anode ratios around 1.…”

Section: Conditions In Structures Governing the Corrosion Ratementioning

confidence: 95%

“…. Micro-cell currents of the steel in carbonated concrete were measured with electrochemical techniques in [48,49] and estimated through gravimetric measurements in [53]. C = cathode, A = anode.…”

Section: Conditions In Structures Governing the Corrosion Ratementioning

confidence: 99%

“…a) Distribution of literature values for the instantaneous corrosion rate in carbonated concrete as a function of moisture exposure condition (adopted from the literature review by Stefanoni et al[47] that is based on more than 20 publications, and including more recent data from[46,[48][49][50]. The width of the blue areas indicates the frequency of occurrence of the different values in the reviewed literature; the crosses are estimated mean values; n is the number of studies.…”

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confidence: 99%

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Corrosion of steel in carbonated concrete: mechanisms, practical experience, and research priorities – a critical review by RILEM TC 281-CCC

et al. 2020

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Carbonation of concrete is generally assumed to lead to reinforcing steel corrosion. This mindset has long dictated the research priorities surrounding the developments towards new, low-emission binders. Here, by reviewing documented practical experience and scientific literature, we show that this widely held view is too simplistic. In fact, there are many cases from engineering practice where carbonation of the cementitious matrix surrounding the steel did not lead to noticeable corrosion or to corrosion-related damage at the level of a structure. The influencing factors that can, however, lead to considerable corrosion damage are identified as the moisture state, the microstructure of the carbonated concrete, various species that may be present – even in minor amounts – in the concrete pore solution, and the cover depth. The circumstance that a reduced pH alone is not sufficient to lead to significant steel corrosion in concrete seriously challenges the established approach of assessing the durability performance based on carbonation testing and modeling. At the same time, this circumstance offers great opportunities for reducing the environmental impact of concrete structures with low-emission binders. To realize these opportunities, the focus in research and engineering should shift from studying carbonation to studying corrosion of steel in carbonated concrete.

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Section: Conditions In Structures Governing the Corrosion Ratementioning

confidence: 95%

Section: Conditions In Structures Governing the Corrosion Ratementioning

confidence: 99%

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confidence: 99%

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Corrosion of steel in carbonated concrete: mechanisms, practical experience, and research priorities – a critical review by RILEM TC 281-CCC

et al. 2020

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“…In structures where steel rebars with different conditions are interconnected, macrocell corrosion is thus expected to be the main corrosion process [162,166]. It is, however, still important to consider both microcell and macrocell components, as the neglect of one of these components may result in underestimating the degree of corrosion [167][168][169]. A schematic representation of the supposed mechanism of carbonationinduced corrosion is shown in Fig.…”

Section: Depassivation and Corrosion Mechanismsmentioning

confidence: 99%

Reinforced concrete structures: A review of corrosion mechanisms and advances in electrical methods for corrosion monitoring

Rodrigues

Gaboreau

Gance

et al. 2021

Construction and Building Materials

184

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Steel corrosion is the main cause of deterioration of reinforced concrete (RC) structures. We provide an up-to-date review on corrosion mechanisms and recent advances in electrical methods for corrosion monitoring. When assessing corrosion mechanism, the inherent heterogeneity of RC structures and the significant effect of environmental factors remain major issues in data interpretations. The steel surface condition and local inhomogeneities at the steel-concrete interface appear to have an important effect on corrosion initiation. Considering uniform corrosion in atmospherically exposed reinforced concrete, the two main influencing factors of the corrosion process are the water content and the pore structure at the steel-concrete interface. However, irrespective of the depassivation mechanism, i.e. carbonation or chloride-induced corrosion, nonuniform corrosion is expected to be the main process for RC structures due to local variations in environmental exposure or the presence of interconnected rebars with different properties. Future studies may then be focused on their effect on macrocell corrosion to gain further insights in the corrosion mechanisms of RC structures. Concerning corrosion monitoring using electrical methods, the half-cell potential technique with potential mapping is accurate for locating areas with a high corrosion risk. Recent developments in the measurement of concrete resistivity have shown that the use of electrical resistivity tomography allows to consider appropriately the inherent heterogeneity of concrete and provides more insights on transport phenomena (e.g. water and salts ingress) in the material. Nevertheless, during the corrosion propagation stage, the polarization resistance remains the most important parameter to be determined as it provides quantitative information of the corrosion rate. If conventional three-electrode configuration methods can supply an accurate determination in the case of uniform corrosion, they often fail in the case of macrocell corrosion in field experiments. Recent advances have shown that a four-electrode configuration without any connection to the rebar can rather be used for the non-destructive testing and evaluation of corrosion. If studies are still required to quantify the corrosion rate, this method appears sensitive to localized corrosion and thus more suitable to field investigations. Finally, the coupling of numerical simulations with complementary electrical and other non-destructive testing methods is essential for consolidating the results to provide a better diagnosis of the service life of RC structures.

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“…Besides some mortar adherences and small surface damages caused by the mechanical cleaning process, only visible pits were found in the bars that showed high anodic currents when they were anodically polarized (S32304 after PI-PC and S32001 after PI-PC and PI). The pits ( Figure 11) appeared mainly in the lower part of the immersed area of the bars, suggesting that there is no special danger associated to partial immersion conditions, in contrast to what occurs with carbon steel reinforced samples, where macrocell corrosion cannot be considered negligible [44]. This difference could be related to the different corrosion mechanisms taking place in stainless steels and in carbon steel.…”

Section: Resultsmentioning

confidence: 97%

Influence of the Alkaline Reserve of Chloride-Contaminated Mortars on the 6-Year Corrosion Behavior of Corrugated UNS S32304 and S32001 Stainless Steels

Bautista

Velasco

Torres-Carrasco

2019

Metals

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The durability of two lean corrugated duplex stainless steel (UNS S32304 and S32001) bars manufactured for concrete reinforcement was studied in four different corrosive conditions. These duplex stainless steels are more economical than the most traditional, well-known duplex grade steels (UNS S32205). The research was carried out in mortar samples for six years. In half of the samples, the alkaline reserve had been previously decreased, and their pH was slightly below 12, while in the other half, the pH close to the bars remained as-manufactured. Moreover, there were samples with modified and non-modified alkaline reserve where chlorides had been previously added to the mortar which were exposed to high relative humidity. In other samples—which were partially immersed in 3.5% NaCl—the chlorides entered through the mortar by natural diffusion. The electrochemical behavior of the reinforcements in these conditions was periodically monitored through corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS) measurements during the whole testing period. The samples were anodically polarized at the end of the exposure. The results prove that the decrease in the alkaline reserve of the mortars can affect the corrosion behavior of the studied lean duplex in environments with high chloride concentrations. The duplex microstructure of the reinforcements makes it so that the corrosion proceeds by selective attack of the phases.

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Macrocell corrosion in carbonated Portland and Portland-fly ash concrete - Contribution and mechanism

Cited by 25 publications

References 17 publications

Corrosion of steel in carbonated concrete: mechanisms, practical experience, and research priorities – a critical review by RILEM TC 281-CCC

Corrosion of steel in carbonated concrete: mechanisms, practical experience, and research priorities – a critical review by RILEM TC 281-CCC

Reinforced concrete structures: A review of corrosion mechanisms and advances in electrical methods for corrosion monitoring

Influence of the Alkaline Reserve of Chloride-Contaminated Mortars on the 6-Year Corrosion Behavior of Corrugated UNS S32304 and S32001 Stainless Steels

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