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Article
Publication date: 1 January 2016

The Huyen Nguyen, Tuan Anh Nguyen, Van Khu Le, Thi Mai Thanh Dinh, Hoang Thai, Xianming Shi and The Huu Nguyen

This work aims to demonstrate the use of electrochemical chloride extraction (ECE) to remove chloride ions away from the steel rebar in chloride-contaminated mortar and to…

191

Abstract

Purpose

This work aims to demonstrate the use of electrochemical chloride extraction (ECE) to remove chloride ions away from the steel rebar in chloride-contaminated mortar and to mitigate the corrosion of the embedded steel.

Design/methodology/approach

To simulate salt contamination in concrete, sodium chloride was added at 0.5 per cent by weight of cement in the fresh mortar featuring a water-to-cement ratio of 0.45. The ECE treatments were varied at two electrical current densities (1 and 5 A/m2), using two electrolytes (0.1M NaOH and 0.1M Na3BO3 solutions) and for two periods (2 and 4 weeks). The average free chloride concentration in cement mortars before and after ECE treatment was quantified using a customized chloride sensor, whereas the spatial distribution of relevant elements was obtained using energy-dispersive X-ray spectroscopy. The effect of ECE treatment on the electric resistivity of mortar and the corrosion resistance of steel rebar was investigated by electrochemical impedance spectroscopy and potentiodynamic polarization measurements, respectively.

Findings

The experimental results reveal that the ECE treatment was effective in removing chlorides and in improving electric resistivity and compressive strength of the mortar, when using the sodium borate solution as the electrolyte. In this case, a 4-week ECE treatment at 1 A/m2 decreased the free chloride content in the mortar by 70 per cent, significantly increased the Ca/Si ratio in the mortar near rebar, led to a more refined and less permeable microstructure of the mortar and significantly improved its compressive strength. The ECE treatment was able to halt the chloride-induced corrosion of steel rebar by passivation. A 4-week ECE treatment at 1 A/m2 using sodium hydroxide and sodium borate solutions decreased the corrosion rate of rebar by 36 and 34 per cent, respectively.

Originality/value

This electrochemical rehabilitation of steel-reinforced concrete under chloride-contaminated condition is very effective in prolonging its service life.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 31 December 2015

Xianming Shi, Greg Hansen, Monty Mills, Scott Jungwirth and Yan Zhang

This paper aims to report the best practices of deicer corrosion control adopted by the Washington State Department of Transportation (WSDOT) to preserve the performance…

417

Abstract

Purpose

This paper aims to report the best practices of deicer corrosion control adopted by the Washington State Department of Transportation (WSDOT) to preserve the performance, reliability and value of its highway maintenance equipment assets.

Design/methodology/approach

To enable quantitative analyses, data were collected from a site visit to WSDOT, as well as from a survey of maintenance practitioners from various transportation agencies. The direct costs related to equipment corrosion aggravated by the exposure to roadway deicers were analyzed, along with the direct benefits of mitigating such corrosion, using WSDOT as a case study. In addition, the same preliminary cost benefit analysis was conducted for an “average” Department of Transportation in a northern climate.

Findings

Both cases show a highly favorable benefit-to-cost ratio for enhanced investment in controlling the risk of deicer corrosion.

Research limitations/implications

It has not yet been possible to confirm this compelling argument because the analysis is partly based on assumptions instead of fully based on actual data.

Practical implications

This work highlights the need to collect the relevant data such that future analysis and sensitivity analysis can be substantiated with actual data on costs and benefits. It concludes with a few suggestions for implementation.

Originality/value

Many components in highway maintenance equipment fleet are at the risk of metallic corrosion, which is exacerbated in service environments where roadway deicers have been applied. This work lays the foundation for future research into this important issue.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 19 May 2012

Yajun Liu and Xianming Shi

The purpose of this paper is to provide a modeling perspective relevant to the use of cathodic prevention (CPre) for unconventional concrete in salt‐laden environment.

814

Abstract

Purpose

The purpose of this paper is to provide a modeling perspective relevant to the use of cathodic prevention (CPre) for unconventional concrete in salt‐laden environment.

Design/methodology/approach

Based on the experimentally obtained concrete resistivity and chloride diffusion coefficient data, numerical studies with the Nernst‐Planck equations were conducted to investigate the influence of applied voltage (magnitude, direction, and interruption), surface chloride concentration, and concrete mix design on the effectiveness of cathodic prevention and the distribution of ionic species in protected concrete.

Findings

The modeling results revealed that the direction of applied electric voltage has significant effect on the distributions of electrical potential and hydroxyl ions in the reinforced concrete, confirming the benefits of cathodic prevention in significantly increasing hydroxyl concentration near rebar and in slowing down the ingress of chloride ingress into concrete. The performance of intermittent CPre was found to be constrained by the variations in concrete resistance from the anode to the cathode. The model was also useful in illustrating the temporal and spatial evolutions on rebar surface in terms of oxygen, hydroxyl and chloride concentrations and electrical potential of top rebar, as well as such evolutions in concrete domain in terms of concrete resistivity and current density for each mix design.

Originality/value

The results reported herein shed light on the fundamental processes defining the performance of CPre for new unconventional concrete in salt‐laden environment.

Details

Anti-Corrosion Methods and Materials, vol. 59 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 9 January 2009

Tuan Anh Nguyen and Xianming Shi

This research aims to unravel the role of salt contamination and corrosion inhibiting admixtures in the processes of cement hydration and rebar corrosion.

2162

Abstract

Purpose

This research aims to unravel the role of salt contamination and corrosion inhibiting admixtures in the processes of cement hydration and rebar corrosion.

Design/methodology/approach

Mortar samples were prepared with NaCl and one of three corrosion inhibitors, sodium nitrite, disodium β‐glycerophosphate, or N,N′‐dimethylethanolamine, admixed. After 28 days curing, all steel‐mortar samples were ponded with 3 percent NaCl solution and electrochemical impedance spectroscopy (EIS) measurements were conducted periodically during the first 48 days. After 60 days of ponding by 3 percent NaCl solution, field‐emission scanning electron microscopy (FESEM) analyses were conducted on the fracture surface of the steel‐mortar sample.

Findings

The FESEM results revealed that admixing chlorides and inhibitors in fresh mortar changed the morphology and cement hydration product of hardener mortar at the steel‐mortar interface. The EIS data indicated that all inhibitors increased the polarization resistance of steel, implying reduced corrosion rate of the steel over 48‐day exposures to salt ponding. 0.05 M N,N′‐dimethylethanolamine was the most effective corrosion inhibitor, followed by 0.5 M sodium nitrite; whereas 0.05 M disodium β‐glycerophosphate was a slower and less capable corrosion inhibitor. The admixing of inhibitors in fresh mortar consistently increased the capacitance and decreased the electrical resistance of hardened mortar. The effect of sodium nitrite inhibitor on the resistance of steel mortar interfacial film compensated that of corrosive NaCl by participating to the formation of a protective ferric oxide film.

Originality/value

The results reported shed light on the complex role of admixed salt and corrosion inhibitors in cement hydration and their implications on the durability of steel‐reinforced concrete.

Details

Anti-Corrosion Methods and Materials, vol. 56 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 28 June 2011

Xianming Shi, Tuan Anh Nguyen, Prathish Kumar and Yajun Liu

This work seeks to present a systematic study that aimed to provide quantitative understanding of the fundamental factors that influence the chloride threshold of pitting…

1120

Abstract

Purpose

This work seeks to present a systematic study that aimed to provide quantitative understanding of the fundamental factors that influence the chloride threshold of pitting corrosion of steel in concrete, by conducting a set of laboratory tests to assess the corrosion potential (Ecorr) and pitting potential (Epit) of steel coupons in simulated concrete pore solutions.

Design/methodology/approach

With the aid of artificial neural network, the laboratory data were used to establish a phenomenological model correlating the influential factors (total chloride concentration, chloride binding, solution pH, and dissolved oxygen (DO) concentration) with the pitting risk (characterized by Ecorr−Epit). Three‐dimensional response surfaces were then constructed to illustrate such predicted correlations and to shed light on the complex interactions between various influential factors.

Findings

The results indicate that the threshold [Cl]/[OH] of steel rebar in simulated concrete pore solutions is a function of DO concentration, pH and chloride binding, instead of a unique value.

Research limitations/implications

The limitations and implications of the research findings were also discussed.

Practical implications

This research could have significant practical implications in predicting the service life of new or existing reinforced concrete in chloride‐laden environments.

Originality/value

This study further advances the knowledge base relevant to the chloride‐induced corrosion of steel rebar in concrete.

Details

Anti-Corrosion Methods and Materials, vol. 58 no. 4
Type: Research Article
ISSN: 0003-5599

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Available. Content available
Article
Publication date: 4 January 2013

220

Abstract

Details

Anti-Corrosion Methods and Materials, vol. 60 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

Available. Content available

Abstract

Details

Anti-Corrosion Methods and Materials, vol. 61 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 29 July 2024

Yongbin Lv, Ying Jia, Chenying Sang and Xianming Sun

This study investigates the causal relationship and mechanisms between the development of digital finance and household carbon emissions. Its objective is to explore how digital…

178

Abstract

Purpose

This study investigates the causal relationship and mechanisms between the development of digital finance and household carbon emissions. Its objective is to explore how digital finance can influence the carbon footprint at the household level, aiming to contribute to the broader understanding of financial innovations' environmental impacts.

Design/methodology/approach

The research combines macro and micro data, employing input-output analysis to utilize data from the China Household Finance Survey (CHFS) for the years 2013, 2015, 2017, and 2019, national input-output tables, and Energy Statistical Yearbooks. This approach calculated CO2 emissions at the household level, including the growth rate of household carbon emissions and per capita emissions. It further integrates the Peking University Digital Financial Inclusion Index of China (PKU-DFIIC) for 2012–2018 and corresponding urban economic data, resulting in panel data for 7,191 households across 151 cities over four years. A fixed effects model was employed to examine the impact of digital finance development on household carbon emissions.

Findings

The findings reveal that digital finance significantly lowers household carbon emissions. Further investigation shows that digital transformation, consumption structure upgrades, and improved household financial literacy enhance the restraining effect of digital finance on carbon emissions. Heterogeneity analysis indicates that this mitigating effect is more pronounced in households during the nurturing phase, those using convenient payment methods, small-scale, and urban households. Sub-index tests suggest that the broadening coverage and deepening usage of digital finance primarily drive its impact on reducing household carbon emissions.

Practical implications

The paper recommends that China should continue to strengthen the layout of digital infrastructure, leverage the advantages of digital finance, promote digital financial education, and facilitate household-level carbon emission management to support the achievement of China's dual carbon goals.

Originality/value

The originality of this paper lies in its detailed examination of the carbon reduction effects of digital finance at the micro (household) level. Unlike previous studies on carbon emissions that focused on absolute emissions, this research investigates the marginal impact of digital finance on relative increases in emissions. This method provides a robust assessment of the net effects of digital finance and offers a novel perspective for examining household carbon reduction measures. The study underscores the importance of considering heterogeneity when formulating targeted policies for households with different characteristics.

Details

China Finance Review International, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2044-1398

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Article
Publication date: 30 January 2025

Xiaohang Ren, Shuiling Hu, Xianming Sun and Dan Zhou

This paper investigates the impact of AI penetration rate on the degree of corporate greenwashing and aims to assess the potential of AI in enhancing firms' environmental…

58

Abstract

Purpose

This paper investigates the impact of AI penetration rate on the degree of corporate greenwashing and aims to assess the potential of AI in enhancing firms' environmental performance and reducing false disclosures.

Design/methodology/approach

This study employs a year and firm fixed-effects model to analyze data from Chinese listed firms from 2012 to 2022. We use the low-carbon city pilot as a quasi-natural experiment to address endogeneity concerns and conduct a series of robustness tests, including adding control variables and transforming the model.

Findings

The results of this paper show that the application of AI can inhibit firms' greenwashing behavior, with green innovation activities further enhancing this inhibitory effect. In state-owned firms and those with Party Organizations, the inhibitory effect of AI on corporate greenwashing is more significant. This reduction in greenwashing is more likely to be observed in firms that are heavily influenced by Confucian culture, receive higher public attention regarding their environmental impact, face less market competition, suffer from more serious pollution and face less financial constraints.

Originality/value

We propose a new research perspective that offers novel insights into promoting the green development of firms by revealing the potential of AI in reducing their greenwashing behavior. Corporate boards can explore specific strategies for applying AI to monitor, prevent and correct greenwashing, thereby enhancing corporate environmental performance and social responsibility.

Details

Journal of Accounting Literature, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0737-4607

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Article
Publication date: 27 September 2021

Joseph Raj Xavier

The purpose of this study is to use polybenzoxazine (Pbz) functionalized ZrO2 nanoparticles to synthesize polyurethane (PU)-PbZ/ZrO2 nanocomposite. The results derived from the…

119

Abstract

Purpose

The purpose of this study is to use polybenzoxazine (Pbz) functionalized ZrO2 nanoparticles to synthesize polyurethane (PU)-PbZ/ZrO2 nanocomposite. The results derived from the electrochemical impedance spectroscopy (EIS) and polarization studies indicated the superior anticorrosive activity of PU-Pbz/ZrO2 nanocomposite coatings compared to those of plain PU coatings. The decreased corrosion current was detected on the scratch of the PU-Pbz/ZrO2 nanocomposite-coated mild steel surface by scanning electrochemical microscopy (SECM) compared to other studied coatings. The superior anticorrosive and mechanical properties of the proposed nanocomposite coatings provide a new horizon in the development of high-performance anticorrosive coatings for various industries.

Design/methodology/approach

The Pbz functionalized ZrO2 nanoparticles were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) and thermogravimetric analysis (TGA) in terms of the structural, morphological and thermal properties of these coatings. A different formulation of coatings such as PU, PU-Pbz, PU-ZrO2 and PU-Pbz/ZrO2 were prepared and investigated for their corrosion protection performance on mild steel in natural seawater by electrochemical techniques. The surface morphological studies were done by SEM/EDX and XRD analysis.

Findings

The superior anticorrosive property of the proposed nanocomposite coatings provides a new horizon in the development of high-performance anticorrosive coatings for various industries. Addition of Pbz wrapped ZrO2 nanoparticles into the PU coating resulted in the blockage of charge transfer at the metal/electrolyte interface, which reduced the dissolution of mild steel. It was revealed from the SEM/EDX analysis that the formation of the corrosion products at the metal/electrolyte interface behaved as the passive layer which reduced the dissolution of steel.

Originality/value

The inclusion of polybenzoxazine functionalized ZrO2 nanoparticles to the polyurethane coating reinforces the barrier and mechanical properties of PU-Pbz/ZrO2 nanocomposite, which is due to the synergistic effect of ZrO2 and Pbz.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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