Quantification of steel-concrete interface in reinforced concrete using Backscattered Electron imaging technique

Chen, Fangjie; Li, Chun‐Qing; Baji, Hassan; Ma, Baoguo

doi:10.1016/j.conbuildmat.2018.05.246

Cited by 36 publications

(10 citation statements)

References 26 publications

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“…The local characteristics of the steel-concrete interface are important parameters as the latter is the seat of the corrosion process. Several techniques can be used to determine the chemistry and microstructure of the interface, such as EDS and BSE imaging [96,100,101]. Special care must be done during sample preparation for such analyses to reduce as much as possible any damage to the steelconcrete interface [102,103].…”

Section: Steel-concrete Interfacementioning

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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Section: Steel-concrete Interfacementioning

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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“…Various types of concrete have a considerable impact on the heterogeneous layer between steel and concrete, denoted as the "transition zone" [139]. This interlayer has high porosity, and the porous zone thickness can affect the RCI strength [140][141][142]. Kenny and Katz [143] showed that the porous zone thicknesses at RCI are 40 and 400 μm for vertically and horizontally cast rebars respectively, which considerably affect the RCI bond strength [144][145][146].…”

Section: Interface Porosity At Rcimentioning

confidence: 99%

A critical review of the effect of concrete composition on rebar–concrete interface (RCI) bond strength: A case study of nanoparticles

2020

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Minimum concrete cover for rebar, rebar diameter, concrete compressive strength, embedded length of rebar, and lateral reinforcement by stirrups are the crucial factors considered in existing predicting equations and regulations for predicting rebar-concrete interface (RCI) bond strength. However, considerable effects of concrete composition on RCI are ignored in design codes and investigations. This paper intends to comprehensively highlight the critical aspects of this research gap. Additionally, a practical experimental approach is described in the present study to efficiently consider the effect of the new generations of concrete on RCI bond strength. Finally, nano-concrete is considered as a case study to show the importance of nanoparticle types on RCI bond strength. Overall results show that studying the microstructure of the transition zone at RCI is essential to accompany with the RCI bond strength for considering new generations of concrete in reinforced concrete structures. Additionally, the current study emphasizes that more investigations are necessary to be conducted by future works to fill the existing research gaps in RCI.

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“…The authors consider that if R pl would be on the order of magnitude of the resistance at low frequency, the ohmic drop at the surface of the passive materials would be huge, and this is not the case. The high-medium frequencies time constant was identified with the resistance (RL) and capacitive behavior (CPEL) of the layer of Ca-rich hydration products formed on the surface of the bars, whose presence and characteristics have been previously studied [37][38][39]. A circuit similar to that in Figure 6b-but without the high-medium frequencies time constant-has been used in other studies to simulate the electrochemical performance of stainless-steel reinforcements in simulated pore solutions [5,12] and in mortar [2,20].…”

Section: Resultsmentioning

confidence: 99%

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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Quantification of steel-concrete interface in reinforced concrete using Backscattered Electron imaging technique

Cited by 36 publications

References 26 publications

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

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

A critical review of the effect of concrete composition on rebar–concrete interface (RCI) bond strength: A case study of nanoparticles

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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