Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Informa {UK} Limited  

To examine the macro-galvanic corrosion of carbon steel near the air–liquid interface, a test panel of array electrodes was developed for investigating the corrosion behaviour in NaCl solution and ...

DOI： 10.1080/1478422x.2021.1943818

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.conbuildmat.2019.07.067

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s13296-018-0067-1

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jcsr.2017.11.007

Authorship：Lead author   Language：English   Publishing type：Doctoral thesis  

収集根拠 : 博士論文（自動収集）

DOI： 10.15017/1866286

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.engfailanal.2017.04.028

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jcsr.2015.11.014

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.engfailanal.2016.05.001

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Electrochemical Science  

This study investigates the corrosion mechanism of carbon steel beneath zinc-rich coating (ZRC) defects to understand the mutual interference of carbon steel in atmospheric environments. First, electrochemical impedance spectroscopy (EIS) was conducted to determine the self-corrosion behavior of carbon steel under ZRC defects. Subsequently, a macrocell current tests were conducted under immersion and wet–dry environments to evaluate the electrochemical interaction effects at the location of coating defects. The results indicate that the electrochemical interactions between the ZRC defects are influenced by the sacrificial anode effect of Zn. Further, the interaction mechanisms between the steel substrates beneath the organic and inorganic ZRC defects were analyzed. The findings provide deeper insight into the behavior of steel structures in atmospheric environments, offering potential improvements in the design of protective coatings for infrastructure longevity.

DOI： 10.1016/j.ijoes.2024.100860

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Buildings  

DOI： 10.3390/buildings14103216

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Construction and Building Materials  

This study investigated the chloride-induced durability deterioration mechanism at the interface of carbon fiber reinforced polymer (CFRP) and steel joints exposure to wet-dry cycling environment, using 27 specimens with varying corrosion levels of steel and aging periods of bonded joints. Characterization including macro and microscale observation, quantification of topographical structure, analysis of surface wettability and adherent residues, were employed to understand the steel surface conditions and their relationship with durability performance under prolonged wet-dry cycles. The results indicated that various steel surface characteristics influenced the interface in both the short and long terms; however, the priority shifted from topography for new steel to cleanliness for corroded steel. As the corrosion level of the steel increased with the aging period, notable declines were observed in the joint's ultimate capacity (∼33.4 %) and its displacement (∼9.94 %) in general responses, along with decreases in maximum slip (∼31.0 %) and shorter plateaus in local responses. This corresponded to an undesirable shift in the triggering failure mode at the ends. Additionally, deterioration mechanism encompassed “foreign attacks” as external factors, marked by corrosion at the bonding edges and inward capillary diffusion of chloride ions, and “domestic unrest” as internal factors, exemplified by the development of those adherent chloride/rust residues, weakening steel-adhesive bonds, and risk of separation. Finally, a time-dependent environmental reduction factor for the capacity model was proposed and verified using collected test data.

DOI： 10.1016/j.conbuildmat.2024.137409

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Steel Structures  

Temperature significantly affects the galvanic corrosion behavior between carbon fiber reinforced plastic (CFRP) and carbon steel. The corrosion rate of steel components in bridges may increase at high temperatures during summer. To examine the impact of solution temperature on the galvanic corrosion between CFRP and carbon steel, electrochemical tests were conducted at different temperatures. The open circuit potential results and potentiodynamic polarization results indicated that the presence of carbon fiber to carbon steel led to increased potential and accelerated corrosion rates. Subsequently, the temperature-promoting factor was used to predict the corrosion rates of steel with galvanic corrosion based on the Arrhenius equation. Finally, the limitations of the temperature-promotion factor were analyzed theoretically.

DOI： 10.1007/s13296-024-00870-3

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Case Studies in Construction Materials  

An ionically conductive sodium polyacrylate-sodium carboxymethyl cellulose (PANa–CMC) hydrogel electrolyte was developed for the sacrificial anode cathodic protection (SACP) of carbon steel in high-humidity environments. The incorporation of varying ratios of CMC into hydrogel formulation enhanced the water retention capacity, adhesion strength, and electrochemical performance, making it suitable for SACP applications. Particularly, PANa-5% CMC hydrogels demonstrated a current density of approximately 3 μA/cm², inhibited passive corrosion product formation, and sequestered metal ions from anodes, thus minimizing contamination. These findings highlight the substantial potential of PANa–CMC hydrogels as electrolytes, expanding the application of the SACP method to atmospheric environments.

DOI： 10.1016/j.cscm.2023.e02742

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Building Engineering  

The effects of a newly developed nozzle type, with divergent flow, and abrasive particle size on the surface preparation properties of steel substrate using abrasive water-jet treatment (AWT) were analyzed. The corrosion and chloride removal efficiencies were evaluated by applying this technique to parts of severely corroded steel structures. The evaluation of the surface characteristics of the treated specimens included analysis of the treatment area, maximum erosion depth, surface roughness profile, and residual abrasive material quantity. The corrosion removal efficiency was assessed using surface salinity measurements and SEM-EDX analysis. The experimental results demonstrated that the application of the developed divergent nozzle and smaller abrasive particle sizes in the AWT process resulted in an expanded treatment range and effective prevention of excessive erosion depth and surface roughness. Additionally, ultra-high-pressure water with abrasives completely eliminated corrosion products and chlorides present on both the surface and interiors of the corroded steel surface, achieving a cleanliness level exceeding Sa 3. This process prevented the formation of flash rust on the cleaned surface for up to 24 h and prolonged the time before the reoccurrence of corrosion on the treated surface. To summarize, the AWT with a divergent nozzle and smaller abrasive particles creates the most ideal surface preparation characteristics for subsequent coating and provides higher surface cleanliness suitable for practical engineering applications.

DOI： 10.1016/j.jobe.2024.108623

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Electrochemical Science  

In the pursuit of sacrificial anode cathodic protection (SACP) for closed-section steel structures exposed to atmospheric conditions, a cotton-like fiber serves as the electrolyte carrier. The efficacy of this approach was validated through assessments of water absorption, retention, electrochemical properties, and SACP trials. The cotton-like fiber exhibited notable hydrophilic characteristics, absorbing nearly seven times its weight of the electrolyte and retaining over 50% of its maximum water absorption capacity after 15 days. Furthermore, the ionic conductivity of the fiber, when fully saturated with 0.1 wt% NaCl aq, was nearly twice that of the same concentration solution without fibers, diminishing as the electrolyte content decreased. Additionally, the open-circuit potential (OCP) of the Al-3Zn sacrificial anode was approximately −0.2 V relative to steel. Moreover, Nyquist plots revealed that electrodes in fibers were more resistant to dissolution compared to those in 0.1 wt% NaCl aq. In the SACP tests, the combination of cotton-like fibers with the Al-3Zn anode exhibited a protective performance for steel members, as assessed by the current density, instant-off potential, and steel surface conditions.

DOI： 10.1016/j.ijoes.2024.100518

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Corrosion Science  

The corrosion interaction mechanism of carbon steel was studied to address the mutual interference of carbon steels under coating defects in the atmospheric environment. The findings revealed that the electrochemical interactions between the carbon steels were primarily influenced by the solution resistance, cathode area, and cathode-to-anode area ratio. In addition, the upper limit of the accelerating effect of the macrocell current on the anodic corrosion rate was determined by theoretical deduction. Finally, the corrosion-accelerating effect of the macrocell current was determined to assess the corrosion rate of carbon steels with electrochemical interactions under defects.

DOI： 10.1016/j.corsci.2023.111730

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Construction and Building Materials  

To assess the impact of corrosion on steel and the effectiveness of surface preparation techniques on the bonding behavior between carbon fiber reinforced polymer (CFRP) and steel, thirty bonded joint specimens were examined. These specimens were based on three distinct corrosion levels of steel and three conventional surface preparation techniques. Furthermore, various evaluation methods were employed to understand the steel surface characteristics, encompassing macro and microscale observations, analysis of topographical structures, and quantification of surface evaluation indices. These were performed to determine their correlations with the interfacial stress behavior. The findings revealed that when the target for repair shifted from a new steel substrate to a corroded one, the synergistic performance at the steel-adhesive interface decreased. This led to a decrease in the maximum shear stress at the plate end, and there was also an undesirable shift in the mode of failure. Both test parameters (i.e., the corrosion level and surface preparation), synergistically determined the surface cleanliness, topography, and bonding defects, all three of which directly influenced the bonding behavior. Finally, an improved model for predicting the debonding capacity of CFRP-corroded steel bonded joints was introduced, incorporating surface damage (k1) and surface topography (k2) coefficients. This model's applicability was also verified by collecting other test data from available literature.

DOI： 10.1016/j.conbuildmat.2023.134279

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

<p> The bond behavior between steel member and carbon fiber sheet is subject to variations based on construction conditions, such as surface preparation methods and curing temperatures. However, there exists considerable uncertainty regarding how these conditions affect the bonding characteristics of carbon fiber sheets, thereby posing challenges in determining the optimal design and construction parameters for reinforcement methods. This study conducted a comparative analysis of four surface treatment methods to assess their effects on the surface properties and adhesive properties of steel substrates. It was also examined the shear strength between steel plates and composite materials. Besides, the study delved into aspects such as the hardening rate, mechanical properties, thermal properties, and fiber penetration of the impregnation resin under different environmental temperatures. Furthermore, an initial isothermal curing model of epoxy resin was constructed, while the vitrification process related to thermal history was speculated. The enhancement brought by the post-curing process on the diverse material properties of epoxy resin was evaluated. The insights of this study have the potential to significantly enhance the bond performance of steel members strengthened with CFRP materials.</p>

DOI： 10.2208/jscejj.23-00250

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Kyushu Association for Bridge and Structural Engineering  

Over the past decade, CFRP strips have been increasingly used worldwide to repair or strengthen steel bridges. However, a large number of researchers use uncorroded steel as the target object before attaching CFRP. This approach is somewhat unreasonable as most steel members that require repair have suffered corrosion damage to different degrees. Additionally, before CFRP retrofitting, the corroded steel should be cleaned first, and the level of steel surface cleanliness is dependent upon the rust-removal method used. Even so, it is difficult to entirely remove all corrosion rust from the steel surface in practical applications. This means that in some cases, interfacial defects are almost inevitably going to occur. Therefore, in this study, the effects of interfacial defects on the corroded steel surface, following three kinds of rust-removal methods (acid solvent, disk sander, and abrasive blast), were primarily evaluated by means of the debonding shear stress at the plate end. In addition, several interfacial defects such as air bubbles, kissing bonds, and secondary rust, were observed based on surface and cross-section analyses using SEM-EDX, respectively. Varying amounts of rust residues tend to induce rust-back, and over time, cause visible under-film corrosion based on the observation of fracture interface. These observations can also provide strong evidence to explain why there is a certain reduction in strengthening effectiveness when using CFRP strips to repair corroded steel, compared to uncorroded steel. Finally, the authors argued that the disk sander in a single way for rust removal was insufficient in the case of repairing corroded steel members with a lot of relatively deep corrosion pits. Because severe rust residues and under-film corrosion observed was likely the primary reason for the adhesive's separation from the steel surface, thereby causing very premature failure of CFRP retrofitting.

DOI： 10.60345/kabse.39.0_85

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Structures  

Resin-impregnated carbon fiber fabric reinforced polymer (CFRP) is a novel material for steel structure reinforcement, but its performance is influenced by moisture and temperature. This study investigates the irreversible degradation of CFRP–steel adhesive joints in a hydrothermal setting, focusing on resin hydrothermal aging behavior. Moisture absorption tests, Fourier-transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) were conducted to assess moisture's impact on resin matrix's properties. Results indicate that moisture absorption behavior is partially reversible through physical drying, while hydrolysis resulting from moisture absorption is irreversible. The partially reversible aspect of moisture absorption leads to a partial restoration of the thermodynamic properties of the resin matrix. Additionally, the mechanical performance of resin specimens and CFRP-steel adhesive joints in hydrothermal conditions was assessed using tensile and pull-off tests. Findings show that elevated temperatures accelerate the moisture absorption rate of resin while increasing the maximum moisture absorption capacity. The moisture absorption affects the fracture surface morphology of the resin matrix, with aging time negatively correlated with adhesion strength. Compared to the hydrothermally aged state, there is a slight recovery in the mechanical performance of CFRP–steel adhesive joints after drying desorption. The saline environment with no significant promotion aging compared to the distilled water environment. These findings provide insights for evaluating CFRP–steel adhesive joints’ durability in atmospheric or marine environments.

DOI： 10.1016/j.istruc.2023.105581

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Construction and Building Materials  

Atmospheric corrosion is one of the most critical issues in steel structures. To improve the structure's durability and reduce its cost, hot-dip coatings are a significant method for steel protection. The corrosion behavior of Al-based hot-dip coatings has been extensively studied. Galvanic corrosion usually occurs when steel members are coated with different hot-dip coatings and placed in direct contact. In this study, galvanic corrosion of an Al coating in contact with a 55Al–Zn coating in an atmospheric environment was investigated through electrochemical and exposure tests. The galvanic corrosion and its mechanism were studied based on open circuit potential (OCP), galvanic current, and X-ray diffraction (XRD) analyses. This study verified the galvanic corrosion of bolt joints in the actual application by the long-term exposure test. The results suggests that 55Al–Zn coating is a good substitute for Zn coating used for bolted joints in contact with Al-coated steel plate.

DOI： 10.1016/j.conbuildmat.2023.132694

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Corrosion Engineering  

<p>Carbon fiber-reinforced plastic （CFRP）-strengthened steel structures are susceptible to galvanic corrosion, especially in high-humidity and marine environments. This study evaluated the key factors influencing galvanic corrosion coupled between carbon fiber and common steel. These factors include the specific electrochemical properties of unidirectional carbon fiber （CF） materials, contact mode between dissimilar materials, and environmental temperature. The results reveal that the carbon filaments and tows were considered physically homogeneous resistors in the fiber direction. However, the surface resistance drops significantly when the CF cloth is in flat contact with a rough conductive metal surface because of the optimized conductive path and enhanced electric contact area. Moreover, based on the Arrhenius equation, this study has developed a simplified model to explain the acceleration effect of temperature on CF-steel galvanic corrosion. It was found that galvanic corrosion is more sensitive to temperature changes than the corrosion of common steel.</p>

DOI： 10.3323/jcorr.72.202

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I032977157

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Lecture Notes in Civil Engineering  

It is commonly duplex layers partially placed on a thermal sprayed coating when narrow parts are difficult to thermal spray. In a previous study, it was shown that when the duplex layer has a defect, thermal spray coating deteriorates faster than the single-layer coating. It is critical to evaluate and anticipate the occurrence and progression of duplex layer degradation and blistering in order to execute effective maintenance management for steel structures. In this investigation, specimens with duplex layers were exposed to the atmosphere and corrosion environment was monitored using ACM-type corrosion sensors and temperature-humidity sensors. Based on these findings, we proposed a method to evaluate the deterioration and blister progression of duplex layer between Al-5Mg thermal sprayed coating and heavy-duty paint coating in an environment without rain-washing action of adhered sea salt.

DOI： 10.1007/978-981-19-4293-8_38

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Lecture Notes in Civil Engineering  

A high-power continuous-wave laser is applied in this study as a replaceable surface treatment method for steel structures. Various forms of corrosion pits will affect the laser treatment efficiency for surface preparation of severely corroded steel structures. In order to evaluate the effect of laser treatment on the steel surface with corrosion pits, carbon steels with artificial pits of various depths and widths were performed and treated by laser irradiation. SEM-EDX analysis distinctly identified laser-treated areas under conditions by mapping elements. Results indicate the laser beam can reach the bottom of pits, promising cleaning efficiency of laser irradiation is still worth expecting.

DOI： 10.1007/978-981-19-4293-8_34

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Lecture Notes in Mechanical Engineering  

A new cathodic protection method including a sacrificial anode and a water swelling rubber was developed and applied to steel members in boundary with ground in the environment of stagnant water and dryness. To ensure applicability, the water swelling rubber was considered as the electrolyte carrier. The reliabilities in water absorption and retention capacity of the rubber were verified by an immersion and drying test. In addition, an electrochemical test was conducted to evaluate the applicability of the water swelling rubber under different environmental conditions. The test results demonstrated that the water absorption and retention performance of the rubber are associated with electrolyte concentration. And the method with the rubber is suitable for immersed and dry environments.

DOI： 10.1007/978-981-19-6841-9_22

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

<p> In steel highway bridges, the multi-layered overlapping coating was adopted in some cases, which applies paint on the sprayed coating. There are many unclear points about the durability and anti-corrosion properties of this overlapped coating film. In this study, to clarify the durability and anti-corrosion characteristics of overlapping layers between Al and Zn thermal sprayed coating and heavy duty paint coating, the specimens of single sprayed coating and overlapping coatings were prepared for the combined cyclic corrosion tests. A cross-cut coating defect was introduced into each specimen. After the test, the coating blister scans and electrochemical measurements on polarization were carried out on specimens, while the cross-section elemental analyses using SEM-EDX, and compound identification by XRD, etc. were also conducted. Test results indicate that the durability of Al overlapping layers is lower than that of the Zn overlapping layer, which deteriorated faster. Moreover, the degradation mechanism of the overlapping coatings between Al- or Zn-based sprayed coating and heavy duty paint coating was investigated, for those exposed to a highly corrosive and salinity environment.</p>

DOI： 10.2208/jscejj.22-00288

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Steel Structures  

Steel box girders are easily subjected to fatigue cracking under the vehicle loading, and the crack initiating from arc notch of diaphragm is one of the typical fatigue details. The stress characteristics of diaphragm and U-rib in real bridge under the vehicle loading were analysed, as well as the deformation characteristics. Experimental work on fatigue crack propagation and bearing capacity was conducted. Simulations using the finite-element method were undertaken, and the crack propagation behaviours were studied. It is found that the out-of-plane deformation is the main cause of crack propagation at arc notch of diaphragm in real bridge. Fatigue testing data of 9 diaphragm-rib specimens carried out by the vibration fatigue test system and results of FEM simulations show that the rate and path of fatigue crack propagation changed significantly during the fatigue crack propagation. The fatigue crack initiates as a tensile-shear mixed mode crack and turns to single tensile mode with the increase of crack length.

DOI： 10.1007/s13296-022-00637-8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Composites Part B: Engineering  

This study focused on the interfacial bond behavior of steel-CFRP (carbon fiber-reinforced polymer) adhesion joint associations with different steel surface treatments through typical pull-off and shear tests. The specimens were fabricated based on wet layup laminating CFRP and clean/corroded steel plates. Four types of surface treatments and two kinds of pre-coating processes were investigated to optimize the interfacial bond behavior. Meanwhile, the conventional rust removal methods were also studied by clarifying the physical and chemical characteristics of steel surfaces. Test results evaluated the topography, microstructure, and surface composition of clean and corroded steel specimens, and qualitatively established their relation to bonding behaviors and failure modes. A strong correlation existed between the surface geometry properties and the tensile/shear strength, however, for clean and corroded steel surfaces their fracture mechanisms differ. Various physical property parameters of the corroded surface related to surface treatment will further affect the bond performance. The corresponding adhesion mechanisms were mathematically demonstrated based on the surface energy principle. The present experimental results provide new insights into the interfacial bond mechanism between corroded steel structures and adhesive or CFRP composites.

DOI： 10.1016/j.compositesb.2022.110280

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.4028/p-9jgv59

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

Finger-type expansion joints (FJs) have been extensively used in highway bridges and are exposed to the repeated impacts of traffic loading and corrosive environments. In this study, the corrosion and cracking behaviors of FJs serving in bridges for more than 25 years were investigated. The microstructure, electrochemical properties, and dynamic response of the FJs were investigated to analyze the fracture mechanism. The results showed that the crack-induced mechanisms of the two main failure modes were different because the synergistic effect of corrosion with residual stress changed depending on the degree of corrosion. First, considerable residual tensile stress, which enhanced the effective stress range, was the critical cause of fatigue crack initiation in the less corroded heat-affected zone (HAZ). Second, the dominant mechanism for cracking was the applied stress to the severely eroded FJ bottom, which was accelerated by galvanic corrosion. Crack-inducing factors included a combination of stress concentration and dynamic springback behavior.

DOI： 10.1016/j.engfailanal.2021.105894

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Lecture Notes in Civil Engineering  

Hot-dip Al coating is an effective and economical protection method for steel structures. Hot-dip Al coated steel members have also been used in the case that contact with concrete. Al is an amphoteric metal that can react with acid and alkaline. Concrete is an alkaline material. The corrosion behavior of hot-dip Al coating contact with concrete is studied by measurement OCP and monitoring the change of pH during the hardening process of concrete. And the atmospheric test that simulates the actual structures. The corrosion products are analyzed by the diffraction of X-rays (XRD). The hot-dip Al coating can be dissolved during the hardening process. With the decreasing pH of concrete, the Al coating also has a relatively stable due to the passivation effect. In the dry and no stagnant water environment, the hot-dip Al coating has a better anti-corrosion behavior due to the passivation and shielding effect of complex calcium-aluminum compounds.

DOI： 10.1007/978-981-16-6932-3_21

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

The effects of blasting with metallic steel grit and non-metallic alumina grit on steel surface characteristics were evaluated. These abrasives are generally used at construction sites and in vacuum blasting. Milled steel specimens were used to investigate the effect of the blasting conditions on surface properties. The effect of difference in surface properties on the adhesion strength and corrosion behavior were measured through adhesion tests, polarization curves, and electrochemical impedance spectroscopy. The limitations of blasting were evaluated using corroded steel specimens, as were the effects of corrosion products, salts, and abrasive material remaining on the blasted steel surface on the adhesion and corrosion resistance of paint. Steel grit more effectively increased the surface roughness than alumina grit; however, with both abrasive materials, the roughness increased with the blast projection angle. However, in the case of alumina grit, some abrasive material remained on the surface; thus, the actual roughness not including the residual abrasive material was more complex and greater than that of the sample blasted with steel grit. According to the adhesion strength test of painted and unpainted specimens, the adhesion force improved with increasing surface roughness and residual abrasive materials. Further, surface roughness was linearly correlated with the adhesion strength of unpainted specimens for both abrasive materials with blasting, and the adhesion strength force with alumina grit was approximately 1.4 times higher than that with steel grit, suggesting that increased roughness and residual abrasive material could benefit adhesion. According to the electrochemical test results, lower roughness and increased residual abrasive material owing to alumina grit on the steel surface enhanced the surface corrosion resistance, confirming the benefit of residual materials. Grinding left behind corrosion products and salts under the steel, resulting in the recurrence of rusting. However, the residue from blasting with alumina suppressed corrosion, thus improving the adhesion and corrosion resistance of the paint.

DOI： 10.3390/met11122065

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Corrosion Engineering  

<p>In the paint-coated steel structures under the air-borne sea salt deposition, corrosion damages were progressed severely where rainwater prone to be stagnated, or exposed to a wet-dry cyclic environment due to the dew condensation. The corrosion of the adjacent coating defects would progress with mutual interference because of the electrical short-circuiting under water film. In this research, a model specimen was fabricated to simulate two adjacent coating defects, and the split electrodes group constituted the relatively larger defect. The exposed steel substrate of the split electrodes corresponding to coating defects and the corrosion currents between each electrode were monitored. Besides, the macrocell current between the split electrodes group and its adjacent coating defect was also measured. Test results clarified the corrosion characteristics between the steel substrate of adjacent coating defects in immersion and wet-dry cyclic environments.</p>

DOI： 10.3323/jcorr.70.271

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media {LLC}  

DOI： 10.1007/s13296-021-00485-y

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

This study focused on the long-term corrosion mechanism of hot-dip aluminum (HDA) coating applied to a steel bridge exposed to a coastal-atmospheric environment. Aging HDA samples were taken from the actual bridge, and the corrosion product composition and morphology of the deterioration stages were investigated. The localized environmental assessment indicated that the surface orientation of the structural members led to a significant difference in salt accumulation and corrosion rate, with the most important influence being the rain-washing effect. Besides, open circuit potential, critical pitting potential, and aging sequence of different metallic phases were clarified. In addition, the long-term deterioration mechanism and pitting growth kinetics of aging HDA were speculated and verified with electrochemistry and elemental analysis.

DOI： 10.1016/j.conbuildmat.2021.122516

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

<p> The zinc-rich coating film has been used as an anti-corrosion primer of the heavy-duty paint coating for the steel structures exposed to the atmospheric environment. However, there are many unclear points about the corrosion protection properties of zinc-containing paints on those regions in steel structure, where the rainwater accumulated, and wet-dry cycles repeated. Moreover, the electrochemical mechanism of steel substrates between coating defects has not been investigated with elucidating its anti-corrosion properties. The objective of this research is to electrochemically elucidate the anti-corrosion properties of the steel substrate exposed at the adjacent coating defects of the organic and inorganic zinc-rich paints, focusing on the stagnated water and repeated wet-dry cyclic condition. Therefore, the model specimens were fabricated to simulate coating defects, and the time-dependent macrocell currents and AC impedance were monitored. Their test results revealed that for the inorganic zinc paints with relatively small diameters of defects, the anti-corrosion acts effectively due to the sacrificial anodic effects of zinc powder and compounds shielding. Nevertheless, the anti-corrosion effect of the organic zinc-rich coating is difficult to generate against the steel substrate.</p>

DOI： 10.2208/jscejseee.77.3_439

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

<p> The objective of this study is to clarify corrosion resistance and anti-corrosion characteristics of the interface between Al-5Mg thermal sprayed coating and heavy duty paint coating in airborne sea salt environment. Atmospheric exposure tests were carried out in highly corrosive atmospheric environments with and without the effect of rainfall washing-off on adhered airborne sea salt. A strip-shaped coating defect was introduced into each specimen, and at the defect area the steel substrate was exposed to the atmosphere. After the exposure tests, the coating blister scans and AC impedance measurements were performed on specimens, while the elemental analyses using SEM-EDX, EPMA, etc. were also conducted. The results indicate that the deterioration occurred from the steel base-exposed portion with the corrosion resistance reduction in the overlapping layer, which deteriorated earlier than that in the single sprayed coating regardless of the atmospheric environment of the exposure sites. Besides, comparing to an airborne salt deposit environment with rain-washing effect, it was clear that this tendency would be more evident in an environment without rain-washing effect.</p>

DOI： 10.2208/jscejseee.77.1_180

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.conbuildmat.2019.117405

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

<p> For the painted steel structures exposed to highly corrosive environments, especially where under the air-borne sea salt deposition, most of the localized corrosion initiates from coating flaws and defects. These corrosion cases would often progress with the mutual interaction between adjacent defects, because of the occurrence of the electrical short circuit around the multiple coating defects due to the stagnated rainwater or dew. This study focused on those regions in steel structure where the rainwater accumulated, and wetdry cycles repeated caused by dew. The objective is to investigate the electrochemical properties of corrosion between adjacent coating defects during the initial stage. Therefore, the model specimens embedded with a plurality of electrodes were fabricated to simulate coating defects, and the time-dependent macrocell currents were monitored between the electrodes. Based on the test results, an estimation method of the corrosion current density was proposed by investigating the electrochemical properties of the three coating defects in the water stagnated environment. Additionally, for the cyclic wet-dry environment, it was clear that the corrosion occurred in small-area defect would be easier to progress than that of a large-area defect.</p>

DOI： 10.2208/jscejseee.76.3_467

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ESG  

DOI： 10.20964/2019.10.40

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Authorship：Lead author,　Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Trans Tech Publications, Ltd.  

DOI： 10.4028/www.scientific.net/MSF.972.235

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

<p> The purpose of this research is to clarify the characteristics of corrosion resistance and anti-corrosion performance of overlapping layers between Al-5Mg thermal sprayed coating and heavy duty paint coating in a high corrosive environment. Accelerated exposure test was carried out on specimens with overlapping layer, and the cross-cut defect were introduced into specimens to form a steel based-exposed portion. In addition, the AC impedance measurements, glossiness tests on the coating surface, and the SEM-EDX elemental analyses on the tested specimens were conducted. The results indicate that the deterioration of the overlapping layer at the steel base-exposed portion occurs earlier than that of the single Al-5Mg thermal sprayed coating. Besides, the generation mechanism of precipitate at the steel base-exposed portion is clarified. Moreover, under the conditions of this combined cyclic corrosion test, the upper layer of heavy duty paint coating still has enough anti-corrosion performance even after the deterioration occurred at the thermal spray coating.</p>

DOI： 10.2208/jscejseee.75.280

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Corrosion Engineering  

<p>The corrosion would often progress with the mutual interaction between adjacent defects, especially at some locations of paint-coated steel structures where the rainwater or dew stagnated in long-term, because of the occurrence of electrical short circuit around the multiple coating defects.</p><p>The objective of this study is to investigate the electrochemical mechanism of mutual interaction between the adjacent coating defects in a stagnant water environment. The model specimens embedded with a plurality of electrodes were fabricated to simulate coating defects, and the corrosion currents were measured between these electrodes. In case of the two electrodes with different diameters, the measurement results show that the anode reaction would be fixed in the electrode with a relative larger diameter, while the cathode reaction would be fixed in the electrode with a small diameter. In addition, when the diameter of the electrode is less than 20 mm, it has been clarified that the linear correlation exists between the area ratio of adjacent electrodes and the macrocell current density, and the relationship was formulated.</p>

DOI： 10.3323/jcorr.67.466

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Corrosion Engineering  

<p>The near-ground boundary of an embedded steel member is especially vulnerable to corrosion, which can be caused by long-term exposure to stagnant rainwater or other environmental factors. Many cases of fracturing due to progressive local corrosion have been reported. This study undertakes a fundamental examination of the output properties and practicality of a corrosion sensor devised by the authors to evaluate the corrosion resistance of steel members near the ground. The output characteristics of this sensor were investigated by simulating NaCl aqueous solution environments, including the atmosphere-liquid interface. In addition, an indoor exposure test was also conducted using uncoated steel plates in the same aqueous solution. The actual corrosion depths obtained from the exposure test were compared with the estimated corrosion depths according to sensor measurements. Moreover, an evaluation method using the corrosion sensor has been proposed for the prediction of the time-dependent corrosion depth of steel members.</p>

DOI： 10.3323/jcorr.67.404

CiNii Research

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.4028/www.scientific.net/KEM.774.619

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.4028/www.scientific.net/KEM.754.55

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

 The objective of this research is to clarify the characteristics of corrosion resistance and anti-corrosion of interface between Al-5Mg thermal sprayed coating and heavy duty paint coating. Accelerated exposure tests were carried out on steel plates with the overlapping and butt layers with introduced linear or strip steel base-exposed portions. In addition, the AC impedance measurements, elemental analyses using EPMA, etc. were also conducted. Their results indicate that the deterioration of the overlapping layer at the steel base-exposed portion occurs earlier than that case of only Al-5Mg thermal sprayed coating. And then, the anti-corrosion performance would be lost after the thermal sprayed coating deteriorates and peels off from steel surface. The overlapping layer deteriorates in an earlier stage and then anti-corrosion performance is easier to decrease as the width of the steel base-exposed portion increases.

DOI： 10.2208/jscejseee.73.496

CiNii Research

Language：Chinese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.measurement.2016.06.040

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1061/(ASCE)CF.1943-5509.0000460

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1179/1432891714Z.000000000465

Authorship：Lead author   Language：Chinese   Publishing type：Research paper (scientific journal)  

DOI： 10.3876/j.issn.1000-1980.2014.05.011

Authorship：Lead author   Language：Chinese   Publishing type：Research paper (scientific journal)  

DOI： 10.3876/j.issn.1000-1980.2014.05.010