A new approach for describing pitting corrosion of steel bars in concrete

2017 ◽  
Vol 64 (6) ◽  
pp. 573-579
Author(s):  
Xinchun Guan ◽  
Lianjuan Miao ◽  
Hui Li ◽  
Jinping Ou
Keyword(s):  
Fractal Dimension ◽  
Pitting Corrosion ◽  
Depth Distribution ◽  
Local Corrosion ◽  
Content Type ◽  
Steel Bar ◽  
Steel Bars ◽  
Two Parameters ◽  
Corrosion Of Steel

Purpose The purpose of this study is to quantitively characterize pitting or local corrosion of steel bars. Characterization of pitting or local corrosion is important for steel bar corrosion research in concrete, which is still an unsolved problem for the reason that the pitting on corroded steel is distributed irregularly, besides the varied pitting depths. To solve this problem in a certain degree, two parameters were collectively used to find the pitting distribution and pitting depth distribution of corroded steel bar surface. Design/methodology/approach Corroded reinforcement bars were subjected to two different corrosive conditions to obtain the profile of the surface of corroded steel bar. The arithmetic mean deviation of the profile, Ra, also a roughness parameter, and the fractal dimension, D, were computed using MATLAB software from the data on corroded steel bar profiles scanned by a profile tester. Statistical analysis was performed to determine the parameters distribution of Ra. Findings Ra and D can assist gravimetric technique in defining the degree of pitting corrosion and make further understanding about the characterization of local or pitting corrosion. Originality/value Two parameters were collectively used to find the pitting distribution and pitting depth distribution of corroded steel bar surface, while many studies only study the fractal dimension of pitting corrosion. And, the relationship between these two parameters is studied when using them to describing the non-uniformity of pitting corrosion degree. Using these two parameters can much better describe the non-uniform degree of pitting corrosion.

scholarly journals Chemical Composition of Corrosion Products of Rebar Caused by Carbonation and Chloride

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Jundi Geng ◽  
Junzhe Liu ◽  
Jiali Yan ◽  
Mingfang Ba ◽  
Zhimin He ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Corrosion Products ◽  
Chloride Salt ◽  
Oxide Content ◽  
Passivation Film ◽  
Steel Bar ◽  
Steel Bars ◽  
Main Components ◽  
Corrosion Of Steel ◽  
Peak Value

The microstructures of steel bars were studied by X-ray photoelectron spectroscopy (XPS), and the mechanism of corrosion of steel bars under the corrosion factors was elucidated. The results show that the passivation film and corrosive surface of the steel surface in the solution of the chloride-containing salt were coarser and the surface state was denser. The main corrosion products are FeOOH and FeO. The surface of the steel immersed in the simulated carbonized solution had loose pores. The main components are FeOOH, Fe3O4, and Fe2O3. The surface of the steel bar has a large amount of yellowish brown corrosion products in the simulated carbonization and chloride salt. The surface of the corrosion products was stripped and the main components are FeOOH, Fe3O4, and FeCl3, where the content of FeOOH is as high as 60%. The peak value of iron is gradually increased from the simulated chloride salt solution to the carbonized solution to the combined effect of carbonation and chloride salt; the iron oxide content is increased and corrosion of steel is obviously serious.

Wave amplitude of embedded ultrasonic transducer-based damage monitoring of concrete due to steel bar corrosion

2021 ◽  
pp. 147592172110417
Author(s):  
Shunquan Zhang ◽  
Zijian Jia ◽  
Yuanliang Xiong ◽  
Ruilin Cao ◽  
Yamei Zhang ◽  
...  
Keyword(s):  
Ultrasonic Transducer ◽  
Steel Corrosion ◽  
Galvanic Current ◽  
Cell Potential ◽  
Accelerated Corrosion ◽  
Electrochemical Testing ◽  
Steel Bar ◽  
Steel Bars ◽  
Damage Process ◽  
Corrosion Of Steel

In this research, four embedded ultrasonic piezoelectric transducers were combined to form cross pair and opposite pair monitoring schemes for continuously monitoring the damage to different strength grades of concrete caused by the corrosion of reinforcements under accelerated corrosion conditions. The damage process was analyzed by combining the electrochemical effects of steel corrosion, that is, half-cell potential and galvanic current tests. Results show that the embedded ultrasonic transducer method can detect damage of concrete during steel corrosion and that each stage of damage can be determined from the plots of ultrasonic transducer data versus corrosion rate. The results further indicate that a combination of cross pair and opposite pair testing methods can more comprehensively reflect the damage to concrete caused by the expansion of corrosion of steel bars, than a single testing method. Since electrochemical testing can only depict the corrosion state of steel rebars, it is beneficial to use embedded ultrasonic measurements to monitor the damage process of concrete. The differences in damage between different strength grades of concrete, that is, the resistance to corrosion of steel bars and brittle failure, can be obtained from the plots of ultrasonic transducer data.

An Experimental Study on the Influence of Steel Bar Corrosion in the Structural Performance of Bridge Piers

2007 ◽  
Vol 348-349 ◽  
pp. 749-752
Author(s):  
In Seok Kang ◽  
Han Seung Lee ◽  
Hai Moon Jung ◽  
Tae Song Ahn
Keyword(s):  
Water Resistance ◽  
Steel Structures ◽  
Bridge Piers ◽  
Economic Losses ◽  
Korean Economy ◽  
Steel Bar ◽  
Steel Bars ◽  
Corrosion Of Steel ◽  
Resistance Performance ◽  
Near Future

Economic losses due to the corrosion of steel structures in concrete is almost about 4% of GNP. It is almost 70 billion dollars in America. Also, The Korean economy is expected to experience a 4～5% loss in GNP in the near future in by considering the industrial background that has been formed by heavy industries. Although deteriorations in concrete structures demonstrate a high diversity of factors, it finally comes down to the lowering of water resistance performance in structures based on the crack generation due to the corrosive expansion of steel bars. Thus, it is very important to investigate the lowering of water resistance performance in structures according to the level of the corrosion in steel bars.

Effects of Coating/Electroplating on Corrosion Resistance of Steel Bar in Reinforced Concrete

2012 ◽  
Vol 446-449 ◽  
pp. 3176-3179 ◽  
Author(s):  
Qun Zhou ◽  
Zhong He Shui ◽  
Yi De Xiao ◽  
Chang Sheng Xu
Keyword(s):  
Corrosion Resistance ◽  
Reinforced Concrete ◽  
Surface Treatment ◽  
Equivalent Circuit ◽  
Surface Coating ◽  
Corrosion Process ◽  
Steel Bar ◽  
Study Results ◽  
Steel Bars ◽  
Corrosion Of Steel

One of the main reasons for the damage of reinforced concrete is the expansion caused by corrosion of steel bar in concrete. In this paper, the equivalent circuit that inflects corrosion process of steel bars in reinforced concrete was analyzed, with the A.C.Impedance Spectrum method. And the effects of surface treatment of the bars on corrosion resistance of the reinforced concrete were investigated. Study results show that the surface coating (plating) on the built-in reinforcement can effectively prevent corrosion of steel bar, thereby enhancing the durability of concrete structures.

scholarly journals Study on the potential change of corroded reinforced concrete in ECE with MPC-CFRP as anode

2020 ◽  
Vol 319 ◽  
pp. 06005
Author(s):  
Yue Li ◽  
Xiuhu Zhang ◽  
S.M.Ali S. Hejazi
Keyword(s):  
Composite Material ◽  
Reinforced Concrete ◽  
Current Density ◽  
Good Effect ◽  
Steel Bar ◽  
Steel Bars ◽  
Cfrp Composite ◽  
Current Densities ◽  
Electrochemical Chloride Extraction ◽  
Corrosion Of Steel

Aiming at the rust removal requirements of reinforced concrete, the MPC-CFRP composite material was used as the external anode, and the Electrochemical chloride extraction (ECE) method was used to test the polarization curve of the steel bar under different ECE current densities, and the potential changes of the steel bar at different times were analyzed. The results show that the ECE system with MPC-CFRP as the external anode has a good effect of reducing the corrosion rate and the risk of corrosion of steel bars. The current density of 3A/m2is higher than that of 1A/m2in dechlorination efficiency. After 28 days of ECE, the current density of 1A/m2and 3A/m2can re passivate the reinforcement.

Bond position function between deformed steel bars and early-age cementitious grout

2021 ◽  
pp. 136943322110157
Author(s):  
Gang Peng ◽  
Ditao Niu ◽  
Xiaopeng Hu ◽  
Xiao Wu ◽  
Yong Zhang
Keyword(s):  
Ultimate Load ◽  
Tensile Load ◽  
Stress Transfer ◽  
Bond Stress ◽  
Load Testing ◽  
Anchorage Length ◽  
Steel Bar ◽  
Steel Bars ◽  
Two Parameters ◽  
Cover Thickness

Pullout tests for the deformed steel bars in early-aged cementitious grout by considering the variables of testing ages, cover thicknesses, and diameters of steel bar were conducted, and the local bond stress–slip relationship at different positions of the anchorage length of steel bar was studied. Results indicated that, with the increase of testing age, the load-slip curves exhibited a higher ultimate load and had steeper ascending and descending branches; however, the slippage at the ultimate load exhibited a decreasing trend. Moreover, with the increase of cover thickness and diameter of steel bar, the ultimate load of pullout specimens increased obviously, while the corresponding slips generally had no obvious correlations. According to an analysis of the measured rebar strain, the distributions of the steel stress and bond stress as well as the relative slip along the embedded length were obtained under different external loads. Steel stress transfer and bond stress distribution parameters were introduced to characterize the nonuniformity of the distributions of the steel stress and bond stress along the steel bar, and the effects of the testing age, cover thickness, and diameter of steel bar on these two parameters were analyzed. Results showed that the both of these two parameters increased with the increasing tensile load, testing age, and cover thickness and with the decreasing diameter of steel bar. Thereafter, the local bond stress-slip relationships along the anchorage length and position functions reflecting the variations of these relationships were proposed.

Fractal Characterization of Corroded Surface Profile in Reinforcing Steel Bars

2010 ◽  
Vol 163-167 ◽  
pp. 3118-3121 ◽  
Author(s):  
Yi Dong Xu ◽  
Chun Xiang Qian
Keyword(s):  
Fractal Dimension ◽  
Surface Profile ◽  
Fractal Dimensions ◽  
Corrosion Damage ◽  
Absolute Measurement ◽  
Reinforcing Steel ◽  
Multi Scale ◽  
Steel Bars ◽  
Fractal Characteristics

Based on fractal geometry theory and surface roughness characterization technology, this paper presents the fractal characterization of nonuniform corrosion degree of corroded reinforcing steel bars. The surface profile curves of different corroded reinforcing steel bars were obtained and their fractal dimensions were calculated in order to describe the fractal characteristics. As is shown by the results, the surface profile curves of rebar have statistical fractal feature. However, fractal dimension is not sensitive to small changes in profile curves. By combining fractal dimension D with scale parameter C, characteristic profile parameter r* is derived to characterize the surface profile of corroded reinforcing steel bars sensitively, which realized the unity of multi-scale similarity measurement and absolute measurement. The results of this analysis will become the basis for corrosion damage evolution of corroded reinforcing steel bars.

Surface characterization of mild steel exposed to atmosphere after being treated by sodium benzoate and dicyclohexylamine nitrite

2016 ◽  
Vol 63 (5) ◽  
pp. 337-346 ◽  
Author(s):  
Ramazan Kahraman ◽  
Huseyin Saricimen ◽  
Zuhair Omar Malaibari ◽  
Md Abdur Rauf
Keyword(s):  
Mild Steel ◽  
Sodium Benzoate ◽  
Surface Characterization ◽  
Steel Corrosion ◽  
Marine Atmosphere ◽  
Gulf Region ◽  
Content Type ◽  
Atmospheric Exposure ◽  
Corrosion Of Steel

Purpose The purpose of this study was to investigate the performances of two inhibitors in controlling corrosion of steel products in industrial and marine atmosphere. Design/methodology/approach Corrosion rates were determined by weight loss measurements. At certain periods of atmospheric exposure, the (disc shape) specimens were retrieved and studied by scanning electron microscopy and energy-dispersive spectrometry surface analysis techniques. Findings Both inhibitors were effective against corrosion of steel in the early stages of the atmospheric exposure (for about two months). With further exposure to the atmosphere, their inhibition effectiveness deteriorated and was totally lost within four months. Analysis of the specimens before exposure showed that the inhibitor film was thin for both treatments, and the unexposed treated surface for both inhibitors appeared similar to the untreated unexposed specimen surface. Characterization of the specimens at different exposure periods showed fewer corrosion blisters on dicyclohexylamine nitrite- and sodium benzoate-treated surfaces than on untreated specimens. Originality/value The objective of this study was to characterize the surfaces of the steel products produced locally during their exposure to the industrial and marine atmosphere of the Arabian Gulf region after being treated by sodium benzoate and dicyclohexylamine nitrite in controlling the corrosion of local mild steel products. According to the literature review, this study is original and will add value to the studies of inhibition of steel corrosion under similar environments.

Applications of SIMS to electronic materials and devices

1992 ◽  
Vol 50 (2) ◽  
pp. 1682-1683
Author(s):  
S.F. Corcoran
Keyword(s):  
Depth Distribution ◽  
Secondary Ion Mass Spectrometry ◽  
Semiconductor Device ◽  
Electronic Materials ◽  
Profile Analysis ◽  
Semiconductor Industry ◽  
Small Diameter ◽  
Depth Resolution ◽  
Detection Sensitivity

Over the past decade secondary ion mass spectrometry (SIMS) has played an increasingly important role in the characterization of electronic materials and devices. The ability of SIMS to provide part per million detection sensitivity for most elements while maintaining excellent depth resolution has made this technique indispensable in the semiconductor industry. Today SIMS is used extensively in the characterization of dopant profiles, thin film analysis, and trace analysis in bulk materials. The SIMS technique also lends itself to 2-D and 3-D imaging via either the use of stigmatic ion optics or small diameter primary beams.By far the most common application of SIMS is the determination of the depth distribution of dopants (B, As, P) intentionally introduced into semiconductor materials via ion implantation or epitaxial growth. Such measurements are critical since the dopant concentration and depth distribution can seriously affect the performance of a semiconductor device. In a typical depth profile analysis, keV ion sputtering is used to remove successive layers the sample.

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