Studies of the corrosion of mild steel in alkali-activated slag cement mortars with sodium chloride admixtures by a galvanostatic pulse method

Holloway, Miles; Sykes, J.M.

doi:10.1016/j.corsci.2005.05.035

Cited by 59 publications

(33 citation statements)

References 10 publications

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“…With such high concentrations of HS -in AAS pore solutions, the amount of dissolved oxygen near the SCI can be expected to be lower than in PC and in PC-GGBS blends [32], driving the redox potential of the embedded steel reinforcement towards more negative values than is generally observed in the passive state in oxidising binders. This was confirmed by Holloway and Sykes [41] and by Criado et al [42], where E corr values for steel embedded in AAS were found to be between -0.45 and -0.60 V vs. Ag/AgCl. The reducing conditions at the SCI in AAS would favour the iron being in the reduced Fe 2+ state, rather than the more usual Fe 3+ state found in passivating oxide films in oxidising binders.…”

Section: Binders With a Reducing Internal Environmentsupporting

confidence: 77%

Section: Binders With a Reducing Internal Environmentmentioning

confidence: 99%

“…Holloway and Sykes [41] studied the corrosion behaviour of steel in AAS mortars containing admixed chloride, and did not observe welldefined trends for either i corr and E corr as a function of the chloride concentration. The E corr values in AAS mortars with chloride concentrations as high as 8 wt.% remained as low as those observed in mortars containing no chloride [41]. Similar observations were made by Criado et al [42] for steel-reinforced AAS, where immersion of mortar specimens in alkaline solutions with and without chloride made no difference to the measured E corr values, which remained around -0.60 V vs Ag/AgCl.…”

Section: Binders With a Reducing Internal Environmentmentioning

confidence: 99%

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Steel corrosion in reinforced alkali-activated materials

et al. 2017

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The development of alkali-activated materials (AAMs) as an alternative to Portland cement (PC) has seen significant progress in the past decades. However, there still remains significant uncertainty regarding their long term performance when used in steel-reinforced structures. The durability of AAMs in such applications depends strongly on the corrosion behaviour of the embedded steel reinforcement, and the experimental data in the literature are limited and in some cases inconsistent. This letter elucidates the role of the chemistry of AAMs on the mechanisms governing passivation and chloride-induced corrosion of the steel reinforcement, to bring a better understanding of the durability of AAM structures exposed to chloride. The corrosion of the steel reinforcement in AAMs differs significantly from observations in PC; the onset of pitting (or the chloride 'threshold' value) depends strongly on the alkalinity, and the redox environment, of these binders. Classifications or standards used to assess the severity of steel corrosion in PC appear not to be directly applicable to AAMs due to important differences in pore solution chemistry and phase assemblage.

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Section: Binders With a Reducing Internal Environmentsupporting

confidence: 77%

Section: Binders With a Reducing Internal Environmentmentioning

confidence: 99%

Section: Binders With a Reducing Internal Environmentmentioning

confidence: 99%

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Steel corrosion in reinforced alkali-activated materials

et al. 2017

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“…Thus, the main aim of the study reported in this paper was to establish the role of the pore solution of AAS on both the chloride transport and chloride induced corrosion in an experiment that is as close as possible to natural exposure conditions. Holloway and Sykes [16] and Gomez et al [17] have studied chloride induced corrosion behaviour of steel embedded in AAS concretes and found that corrosion rate was favourable compared to the PC counterpart. Holloway and Sykes [16] have simulated corrosion using internal chlorides, i.e., introduced into the matrix during mixing, whereas Gomez et al [17] have used continuous immersion.…”

Section: Introductionmentioning

confidence: 99%

“…Holloway and Sykes [16] and Gomez et al [17] have studied chloride induced corrosion behaviour of steel embedded in AAS concretes and found that corrosion rate was favourable compared to the PC counterpart. Holloway and Sykes [16] have simulated corrosion using internal chlorides, i.e., introduced into the matrix during mixing, whereas Gomez et al [17] have used continuous immersion. Therefore, in order to have a full picture of the application of AAS concretes to all types of chloride exposures, a severe exposure environment of wetting/drying (chloride ponding) was used in this study.…”

Section: Introductionmentioning

confidence: 99%

Chloride transport and the resulting corrosion of steel bars in alkali activated slag concretes

et al. 2015

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As the relative performance of alkali activated slag (AAS) concretes in comparison to portland cement (PC) counterparts for chloride transport and resulting corrosion of steel bars is not clear, an investigation was carried out and the results are reported in this paper. The effect of alkali concentration and modulus of sodium silicate solution used in AAS was studied. Chloride transport and corrosion properties were assessed with the help of electrical resistivity, non-steady state chloride diffusivity, onset of corrosion, rate of corrosion and pore solution chemistry. It was found that: (i) although chloride content at surface was higher for the AAS concretes, they had lower chloride diffusivity than PC concrete; (ii) pore structure, ionic exchange and interaction effect of hydrates strongly influenced the chloride transport in the AAS concretes; (iii) steel corrosion resistance of the AAS concretes was comparable to that of PC concrete under intermittent chloride ponding regime, with the exception of 6 % Na 2 O and Ms of 1.5; (iv) the corrosion behaviour of the AAS concretes was significantly influenced by ionic exchange, carbonation and sulphide concentration; (v) the increase of alkali concentration of the activator generally increased the resistance of AAS concretes to chloride transport and reduced its resulting corrosion, and a value of 1.5 was found to be an optimum modulus for the activator for improving the chloride transport and the corrosion resistance.

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Application of electrochemical methods for studying steel corrosion in alkali‐activated materials

Mundra

Samson

Masi

et al. 2023

Materials & Corrosion

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Alkali-activated materials (AAMs) are binders that can complement and partially substitute the current use of conventional cement. However, the present knowledge about how AAMs protect steel reinforcement in concrete elements is incomplete, and uncertainties exist regarding the application of electrochemical methods to investigate this issue. The present review by EFC WP11-Task Force 'Corrosion of steel in alkali-activated materials' demonstrates that important differences exist between AAMs and Portland cement, and between different classes of AAMs, which are mainly caused by differing pore solution compositions, and which affect the outcomes of electrochemical measurements. The high sulfide concentrations in blast furnace slag-based AAMs lead to distinct anodic polarisation curves, unusually low open circuit potentials, and low polarisation resistances, which might be incorrectly interpreted as indicating active corrosion of steel reinforcement. No systematic

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Studies of the corrosion of mild steel in alkali-activated slag cement mortars with sodium chloride admixtures by a galvanostatic pulse method

Cited by 59 publications

References 10 publications

Steel corrosion in reinforced alkali-activated materials

Steel corrosion in reinforced alkali-activated materials

Chloride transport and the resulting corrosion of steel bars in alkali activated slag concretes

Application of electrochemical methods for studying steel corrosion in alkali‐activated materials

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