Role of mill scale on corrosion behavior of steel rebars in mortar

Doi, Kotaro; Hiromoto, Sachiko; Shinohara, Tadashi; Tsuchiya, Koichi; Katayama, Hideki; Akiyama, Eiji

doi:10.1016/j.corsci.2020.108995

Cited by 22 publications

(15 citation statements)

References 35 publications

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“…The outer layer of the pre-rusted specimens in groups B and C was separated from the rebar by a narrow crack along the interface, but the separation was not apparent in the group A specimens. The layer thickness of the non-corroded reinforcement group A was measured to be about 7.1 µm; other researchers reported that the thickness of the non-corroded reinforcement layer was about 10 µm [27,28]. The outer layer measured 15.33 µm for group B and 35.58 µm for group C, indicating that the amount of pre-corrosion in the group C rebar was approximately twice that in the group B rebar.…”

Section: Scanning Electron Microscopy Analysis and X-ray Diffractionmentioning

confidence: 88%

Corrosion Behavior of Pre-Rusted Rebars in Cement Mortar Exposed to Harsh Environments

et al. 2020

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Rebar embedded inside reinforced concrete structures becomes corroded due to various factors. However, few studies have focused on the corrosion of pre-rusted rebar embedded in cement composites, and the findings reported thus far are inconsistent. Therefore, in this study, an experimental program was undertaken to examine the effect of pre-rusting on the further corrosion of reinforcements in cement composites. Pre-rust was induced using two different solutions (CaCl2 and HCl). The corrosion rate in the cement composite was analyzed using the half-cell potential and polarization resistance methods. In addition, scanning electron microscopy with energy-dispersive X-ray analysis and X-ray diffraction analysis were used to examine the morphology of the rust. The results show that the corrosion rate of the rebar embedded in the cement composite can be increased by more than 3.8 times depending on the pre-rust conditions (RE: 0.0009 mm/year, HCl: 0.0035 mm/year). In addition, we found that the corrosion products in the pre-rusted layer were comparable to those of the rebar corroded in the marine atmosphere.

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Section: Scanning Electron Microscopy Analysis and X-ray Diffractionmentioning

confidence: 88%

Corrosion Behavior of Pre-Rusted Rebars in Cement Mortar Exposed to Harsh Environments

et al. 2020

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“…Optical microscopy via stereo or compound microscopes can be used to characterise the morphology (i.e., thickness, pattern, and distribution) of mill scale and rust layers on the steel surface in a relatively fast and cost-effective manner. The technique can be used on rebar as received from the mill [12,16], after mechanical separation from mortar/concrete [17], or as part of a general investigation of SCI on sectioned samples [16,18]. Optical microscopy can also visualise corrosion products that form and their penetration into pores and cracks in the surrounding concrete [19].…”

Section: Optical Microscopymentioning

confidence: 99%

“…Therefore, optical microscopy is usually complemented with other techniques such as scanning electron Fig. 3 Optical micrographs showing a mill scale discontinuity on rebar surface, and b morphology of mill scale and rust layers on a cross-section of reinforced mortar subjected to chloride-induced corrosion [16] microscopy (SEM) coupled with energy dispersive X-ray (EDX) spectroscopy or Raman spectroscopy.…”

Section: Optical Microscopymentioning

confidence: 99%

“…The SE mode uses low-energy elastically scattered electrons to give morphological and topographic information at nanoscale resolution. The BSE mode is particularly useful because it allows differentiation between mill scale, rust layers and other phases [12,[16][17][18][19]22] based on their atomic contrast and brightness intensity (see also Sect. 4.2.2).…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

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Methods for characterising the steel–concrete interface to enhance understanding of reinforcement corrosion: a critical review by RILEM TC 262-SCI

Wong,

Angst,

Geiker

et al. 2022

Mater Struct

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The steel–concrete interface (SCI) is a complex, multi-phase and multi-scale system. It is widely known to influence the performance and long-term durability of concrete structures. However, a fundamental understanding of its properties and effects on corrosion initiation of embedded reinforcing steel remains elusive. This is attributed to its complicated heterogeneity and time-dependent nature, exacerbated by the lack of suitable techniques for systematic and detailed characterisation. This paper, prepared by members of the RILEM Technical Committee 262-SCI, critically reviews available information regarding current methods (laboratory or field-based) for characterising local properties of the SCI that have been identified as governing factors affecting corrosion initiation. These properties include characteristics of the steel such as mill scale and rust layers, and characteristics of the concrete such as interfacial voids, microstructure and moisture content. We evaluated over twenty methods and summarised their advantages, applications and limitations. The findings show a severe lack of well established, non-destructive techniques that are suitable for direct monitoring of the SCI at a representative scale with sufficiently high resolution (spatial, temporal), particularly for moisture related aspects. Several promising novel techniques with significant potential for further development and application were identified and discussed. Finally, we provide several recommendations for future research needs that are required to advance this critically important topic.

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“…Besides, there are several types of physico-chemical, electrochemical, and biological processes occurring on the reinforced steel (rebar) surface in concrete structures in presence of aggressive environmental factors. They accompanied by reduction of pH values of the concrete structures below 10 [12,13], which starts depassivation and initiation of corrosion on the rebar surface leading to the loss of functionality, durability, structural integrity and finally resultant safety risks, and economic losses to human beings [14]. The corrosion products formed on the rebar surfaces reduce the gripping force with the concrete matrix and affect the quality of the whole reinforcing concrete infrastructures [15].…”

Section: Introductionmentioning

confidence: 99%

Study on the effects of green-based plant extracts and water-proofers as anti-corrosion agents for steel-reinforced concrete slabs

et al. 2021

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Widespread applications of reinforced concrete structures have been practiced since the 20th century because of their excellent properties despite their early corrosion degradation. For the control of such a problem, a design strategy of corrosion-resistant environments of the reinforced concrete structures is highly desirable for extending of a lifetime. The present research work was focused to investigate the effects of the green plant extract-based inhibitors from Vitex negundo and Catharanthus roseus leaves, and one waterproofing chemical (PtS) for controlling the corrosion susceptibility of concrete rebar using a half-cell potential method following the ASTM C876-91 standard. Both plant extracts have good anti-corrosion properties, and hence could be applied as green concrete additives to increase the corrosion resistance of the steel reinforcing bars. The anti-corrosion performance of the steel rebars in concrete is remarkably higher with the additions of 1000 and 2000 ppm plant extracts than the additions of waterproofing chemicals used, based on the shifting of corrosion potential (ϕcorr.) values to a more positive direction than −126 mV (SCE). The results agreed that both the plant extracts could be promising for the formulation of effective, ecofriendly anti-corrosion additives to delay the corrosion susceptibility of the concrete infrastructures.

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Role of mill scale on corrosion behavior of steel rebars in mortar

Cited by 22 publications

References 35 publications

Corrosion Behavior of Pre-Rusted Rebars in Cement Mortar Exposed to Harsh Environments

Corrosion Behavior of Pre-Rusted Rebars in Cement Mortar Exposed to Harsh Environments

Methods for characterising the steel–concrete interface to enhance understanding of reinforcement corrosion: a critical review by RILEM TC 262-SCI

Study on the effects of green-based plant extracts and water-proofers as anti-corrosion agents for steel-reinforced concrete slabs

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