The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Changjian Lin - One of the best experts on this subject based on the ideXlab platform.
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Effect of pH on the Corrosion Behavior of Reinforcing Steel in Simulated Concrete Pore Solutions
ECS Transactions, 2019Co-Authors: Yan-feng Zhu, Fang-miao Tang, Wen Chen, Changjian LinAbstract:Reinforcing Steel in concrete is usually in a passive state due to the high alkalinity of the concrete pore solution. However, the passivity may be lost and the corrosion occurs on the Steel by a decrease of pH due to carbonation. In this work, the effect of pH on the corrosion behavior of Reinforcing Steel in simulated concrete pore solutions was studied by potentiodynamic anodic polarization, a scanning microreference electrode and scanning electron microscopy. The results showed that Reinforcing Steel exhibited different corrosion characteristics in the solutions with different pH values, the Steel was in a state of passivity in the pure simulated pore solution, and the potential distribution on the Reinforcing Steel surface changed in homeostasis. When the pH value of the solution decreased to 11.30, localized corrosion occurred on the Steel surface by the measurement of the Steel potential distribution. This value is higher than that of the polarization curve measurements
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Effective monitoring of corrosion in Reinforcing Steel in concrete constructions by a multifunctional sensor
Electrochimica Acta, 2011Co-Authors: Shi-gang Dong, Changjian LinAbstract:A novel multifunctional sensor is developed for in situ and non-destructive monitoring of the corrosion current and open circuit potential of Reinforcing Steel, as well as the pH and Cl− concentration of concrete. The pH and Cl− sensors show good responses to the pH and Cl− concentration of concrete pore solutions, respectively, and are able to monitor both the carbonization process of concrete and the ingress of Cl− in concrete. Combined with measurements of the corrosion potential and corrosion current density, as well as the EIS spectra of Reinforcing Steel in concrete, this study demonstrates that the pH and the Cl− concentration of concrete are two of the most crucial factors that determine the corrosion of Reinforcing Steel in concrete. The corrosion tendency and corrosion rate of Reinforcing Steel largely depend on the chemical environment in the concrete. The multifunctional sensor is a powerful tool for in situ monitoring corrosion of Steel in concrete, and provides accurate details of the chemical condition of the concrete pore solution and the corrosion status of the Reinforcing Steel in concrete. These are essential for corrosion predictions and service life evaluations of concrete constructions.
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Electrochemical Study on the Corrosion Behavior of Reinforcing Steel in Alkaline Solutions
2008Co-Authors: Yu Liu, Changjian LinAbstract:The corrosion of Reinforcing Steel in concrete is the main reason for the premature degradation of a reinforced concrete structure. Study on the depassivation behavior of Reinforcing Steel is of great importance to the investigation on the corrosion and protection of Steel in concrete (1). In this work, the potentiodynamic anodic polarization and scanning reference electrode technique (SRET) were used to study the localized corrosion behavior of the Reinforcing Steel in alkaline solutions with different pH values and chloride ion concentrations. A saturated calcium hydroxide solution was used as an alkaline solution, and referred to as the simulated concrete pore solution for the Reinforcing Steel corrosion test. The Cl concentration and pH in the test solution was adjusted by adding NaCl and NaHCO3 to the solution, respectively. R235 Reinforcing Steel was used in this investigation. Potentiodynamic anodic polarization curve measurements were all performed in a three-electrode cell by Autolab Potentiostat/Galvanostat. The potential of the Steel was reported with respect to a saturated calomel electrode (SCE). The potential distribution on the Steel surface was determined by SRET at open circuit potential using a home-designed SMRE system (2, 3). The Ag/AgCl microelectrodes improved in our laboratory were used as the scanning electrode and the reference electrode (2). All the electrochemical measurements were carried out at room temperature (23±2C). The potentiodynamic anodic polarization measurements showed a passive region occurred in the polarization curve for the Reinforcing Steel in the pure simulated concrete pore solution, and the Steel remains unattacked. However, the corrosion behavior of the Reinforcing Steel varied considerably, the passive region was lost as the Cl concentration in the solution increased to a certain value, and the localized corrosion of the Steel took place. The effect of chloride ions on passivity breakdown of the Steel was observed from measuring the breaking potential of the Steel, and the chloride depassivation threshold value was between 0.50~0.60 mol/L in a pH12.50 simulated concrete pore solution. The potential distribution on the Steel surface measured by SRET indicated that the Reinforcing Steel exhibited different corrosion characteristics in different solutions. The Steel remained passive in the pure saturated Ca(OH)2 solution although some unstable micro-pitting nuclei occurred on the Steel surface. After the Steel was immersed in the solution with 0.05 mol/L Cl and pH 10.16, there were some obvious stable potential peaks on the Steel surface, and the localized corrosion occurred rapidly, then the height of potential peaks increased with time, and the pitting corrosion kept developing. The corrosion inhibition effect of some inhibitors on Reinforcing Steel in alkaline solutions with NaCl was also evaluated in the present work. The results indicated a new sodium nitrite-based composite corrosion inhibitor developed in our laboratory could effectively inhibit the initiation of corrosion for the Reinforcing Steel immersed in the alkaline solution with 3.5% NaCl and pH 11.00 by adding 2.5% inhibitor to the solution.
Ronggui Du - One of the best experts on this subject based on the ideXlab platform.
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corrosion behavior of Reinforcing Steel in simulated concrete pore solutions a scanning micro reference electrode study
Electrochimica Acta, 2009Co-Authors: Hui Xu, Ronggui DuAbstract:The scanning micro-reference electrode (SMRE) technique was used to study the corrosion behavior of Reinforcing Steel in simulated concrete pore (SCP) solutions with different pH values. The early stage as well as the propagation of the localized corrosion of Reinforcing Steel in different solutions was explored. The results indicated that the potential distribution on the Reinforcing Steel surface changed in homeostasis and the Steel remained passive in the pure simulated concrete pore solution. The solution pH had a significant effect on the localized corrosion of Reinforcing Steel, and the critical pH value for localized corrosion of Reinforcing Steel in SCP solutions was between 11.46 and 11.31.
Jinping Ou - One of the best experts on this subject based on the ideXlab platform.
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corrosion monitoring of Reinforcing Steel in cement mortar by eis and ena
Electrochimica Acta, 2007Co-Authors: Guofu Qiao, Jinping OuAbstract:Health degradation by corrosion of Steel in civil engineering, especially in rough environment, is a persistent problem. Environment pollution and global warming will exacerbate this problem. The assessment of whole-life costing and residual service life prediction of structures is very important. Pitting corrosion is the most important factor which influences the service life of the reinforced concrete structures in many chloride included environments. Electrochemical impedance spectroscopy (EIS) method is used to study the corrosion process of Reinforcing Steel in cement mortar. According to the results of the experiments, dispersion and diffusing effect control the electrochemical process of carbon Steel corrosion in the cement mortar. By fitting the results with EC, the parameters about CPE and Warburg impedance are calculated. The pitting corrosion behavior of Reinforcing Steel in cement mortar has been studied by electrochemical noise analysis (ENA) method, the wavelet transform has been employed to analyze the EN data of Reinforcing Steel in mortar, and the energy distribution plot (EDP) is plotted. The experimental results show that the change of EDP during the corrosion process can qualitatively reveal useful information on corrosion mechanisms.
Abd El S Wanees - One of the best experts on this subject based on the ideXlab platform.
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initiation and inhibition of pitting corrosion on Reinforcing Steel under natural corrosion conditions
Materials Chemistry and Physics, 2017Co-Authors: Abd El S Wanees, Bahgat A Radwan, Meshari A Alsharif, S Abd El M HaleemAbstract:Abstract Initiation and inhibition of pitting corrosion on Reinforcing Steel in saturated, naturally aerated Ca(OH)2 solutions, under natural corrosion conditions, are followed through measurements of corrosion current, electrochemical impedance spectroscopy and SEM investigation. Induction period for pit initiation and limiting corrosion current for pit propagation are found to depend on aggressive salt anion and cation-types, as well as, concentration. Ammonium chlorides and sulfates are more corrosive than the corresponding sodium salts. Benzotriazole and two of its derivatives are found to be good inhibitors for pitting corrosion of Reinforcing Steel. Adsorption of these compounds follows a Langmuir adsorption isotherm. The thermodynamic functions ΔE∗, ΔH∗ and ΔS∗ for pitting corrosion processes in the absence and presence of inhibitor are calculated and discussed.
Lin Chang-jian - One of the best experts on this subject based on the ideXlab platform.
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Study on the anticorrosion of D-sodium gluconate on Reinforcing Steel in simulated concrete pore solution
Journal of Functional Biomaterials, 2007Co-Authors: Lin Chang-jianAbstract:The inhibiting effect of D-sodium gluconate on the Reinforcing Steel immersed in the simulated concrete pore solution with 0.1mol/L NaCl was studied by EIS.The results indicate that 0.01mol/L D-sodium gluconate has a good effect on the Reinforcing Steel in anticorrosion.The Reinforcing Steel is prevented from corrosion by the formation of an adsorptive film on the Steel surface because the gluconate anions compete against the chloride ions in the adsorption.
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Effect of Chlorine Ions on the Corrosion Behavior of Reinforcing Steel in Concrete
Materials protection, 2006Co-Authors: Lin Chang-jianAbstract:A review was given to summarize the effect of chlorine ions on the corrosion behavior of Reinforcing Steel in concrete and the progress of the related research.Thus the corrosion behavior of the Reinforcing Steel,the deactivation mechanism of chlorine ions,the source of the chlorine ions in the concrete,the measures to protect the Reinforcing Steel,and the related research progress were highlighted.It was pointed out that the corrosion of the Reinforcing Steel in concrete was mainly attributed to chlorides,since the chlorine ions are able to destroy the passive film,induce localized corrosion of the Reinforcing Steel,and catalyze the corrosion process.However,the chlorides would not lead to corrosion of the Reinforcing Steel unless their concentration rose to a certain threshold value.Unfortunately,no widely acceptable threshold concentration of the chlorine ions causing the corrosion of the Reinforcing Steel is available so far,which is largely attributed to its dependence on various factors.
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Effect of Chloride Ions on the Corrosion Behavior of Reinforcing Steel in Simulated Concrete Pore Solutions
Electrochemistry, 2005Co-Authors: Du Rong-gui, Lin Chang-jianAbstract:The potentiodynamic anodic polarization was used to study the corrosion behavior of the Reinforcing Steel in simulated concrete pore solutions with different pH and chloride ion concentrations. The effect of chloride ions on passivity breakdown of the Steel was examined by measuring the breaking potentials of Reinforcing Steel, and the critical chloride concentrations for depassivation were found in simulated concrete pore solutions at pH 12.50 and pH 12.00.
