The Tests and Measures of Concrete Ageing and Steel Bar Corrosion of the Salt Free Contaminated Inland Waterlocks

2011 ◽  
Vol 71-78 ◽  
pp. 4525-4532
Author(s):  
Jin Yang Zhang
Keyword(s):  
Concrete Surface ◽  
Potential Method ◽  
Cell Potential ◽  
Railway Bridges ◽  
Hydraulic Concrete ◽  
Steel Bar ◽  
Steel Bars ◽  
Aging Phenomena ◽  
Peeling Off ◽  
Test Result

There are mainly three phenomena, i.e. cracks, infiltration and denuding for judging the aging and defects from hydraulic concrete constructions. The inland waterlocks’ concrete ageing with salt free contamination are found basically the concrete denuding, rebar erosive expansion cracks and concrete surface gravel exposure and freeze thawing peeling-off as well occasionally. The severe aging phenomena always occur in some small structures in work bridges, sub work bridges, railway bridges and concrete waterlocks etc, especially in boundary beams or flange plates of the said beams. The result manifests that the test result is completely in conformity with the actual situation in the test of internal concrete steel bar erosion by means of Eigenvalue K method and half-cell potential method. In order to prevent steel bars in the concrete from eroding and guarantee the durability of waterlocks, currently the treating method used most frequently is the waterlock concrete surface carbonization resistance treatment

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.

Experimental Study on the Corrosion Rate of Rebars in Chloride-Contaminated Concrete with Adding or Painting Inhibitors

2013 ◽  
Vol 671-674 ◽  
pp. 674-677
Author(s):  
Lei Yu ◽  
Zhi Yong Liu ◽  
Hao Xia Sun
Keyword(s):  
Corrosion Current ◽  
Concrete Surface ◽  
Cementitious Materials ◽  
Concrete Sample ◽  
Hardened Concrete ◽  
Green Concrete ◽  
Cover Concrete ◽  
Steel Bar ◽  
Steel Bars ◽  
Better Than

Tests were conducted to investigate the inhibiting effect on steel bars in concrete contaminated with 0.75% (wt.) chloride of the cementitious materials by adding inhibitor in green concrete or surface painting inhabitor on cover concrete. The results show that the anticorrosion effect of surface painting inhibitor on concrete with 30mm cover at 400g.m-2 are mainly better than that of adding 2% inhibitors in concrete with 0.75%(wt.) NaCl of the cementitious materials. The minimum corrosion current of steel bar in concrete sample after painting MCI-C12 28 days can be reduced to 0.084 μA.cm-2 from 1.30 μA.cm-2 of the sample before painting inhibitor. The corrosion current of steel bars in concrete samples painted with MCI-2010 and sodium nitrite solution are roughly equal to that of the control concrete sample without chloride, and less than that of the sample added in nitrite and chloride. Compared with mixed inhibitor in green concrete, surface applied inhibitor on hardened concrete not only avoid to affect the properties of concrete, but also bring to the visible economical advantage.

Resistance of Chlorides-Induced Corrosion of Steel Bar Embedded in CNTs-OH Modified Concrete

2018 ◽  
Vol 768 ◽  
pp. 320-325
Author(s):  
Zhong Kun Wang ◽  
Jie Fan ◽  
Geng Ying Li
Keyword(s):  
Corrosion Potential ◽  
Potential Method ◽  
Test Results ◽  
Pore Filling ◽  
Half Cell ◽  
Cell Potential ◽  
Air Interface ◽  
Steel Bar ◽  
Corrosion Of Steel ◽  
Oh Content

Aim of this paper is to evaluate the influence of hydroxyl carbon nanotubes (CNTs-OH) content (by 0.1-0.5% of cement weight) on the resistance of chlorides-induced corrosion of steel bar embedded in concrete. The corrosion process of concrete was monitored by using half-cell potential method (Ecorr, mv CSE). Test results show that the addition of CNTs-OH considerably increased the resistance of rebar chlorides induced corrosion of concrete, and the optimum content of CNTs was about 0.3% by mass of cement. Simultaneously, results also indicate that the measuring position impacted the corrosion potential value, in which the point on the water/air interface had the highest corrosion probability. In addition, the water absorption and SEM of concrete containing CNTs-OH were also investigated, and the pore-filling effect of CNTs-OH was observed to improve the properties of concrete.

Research on Chloride Appropriate Dosage for Incorporated Accelerated Corrosion

2014 ◽  
Vol 989-994 ◽  
pp. 458-461
Author(s):  
Qi Xia Liu ◽  
Shu Lin Zhan
Keyword(s):  
Compressive Strength ◽  
Corrosion Potential ◽  
Potential Method ◽  
Polarization Potential ◽  
Half Cell ◽  
Cell Potential ◽  
Accelerated Corrosion ◽  
Steel Bars ◽  
Corrosion State ◽  
Potential Curves

Mixing chlorine is one of the ways to ensure the theory and practical steel bars corrosion rate closer when mixing concrete for laboratory electrochemical accelerated corrosion and appropriate chloride dosage should guarantee the steel bars are in the critical corrosion state when we start to accelerated corrosion. By comparing the specimens’ experimental compressive strength, chloride-permeation resistance, corrosion potential measured by the half-cell potential method and polarization potential curves measured by the linear polarization potential method with different Nacl dosage, we get the appropriate Nacl dosage is nearly 1.90%, namely cl- content is about 1.15%.

scholarly journals Study of the reinforcement of structure members by polypropylene fibres waste

2018 ◽  
Vol 149 ◽  
pp. 01022 ◽  
Author(s):  
Khadra Bendjillali ◽  
Mohamed Chemrouk
Keyword(s):  
Reinforced Concrete ◽  
Significant Contribution ◽  
Concrete Beams ◽  
Average Diameter ◽  
Concrete Surface ◽  
Point Of View ◽  
Reinforced Concrete Beams ◽  
Polypropylene Fibres ◽  
Steel Bars ◽  
Material Durability

The valorisation of industrial waste in the field of construction became a very interesting axis of research from scientific, economic and environmental point of view. We have conducted this work to study the effect of the addition of polypropylene fibres waste on the mechanical behaviour of reinforced concrete beams subjected to a simple flexural loading, with and without transversal reinforcement. The used fibres are coming from the waste of the fabrication of domestic brushes and sweeps; they have an average diameter of 0.47 mm and a length between 40 and 60 mm. Two weight dosages of fibres are used, 0.25 and 0.5 %. The experimental results showed that the incorporation of polypropylene fibres waste into the concrete affects negatively its workability, but its flexural and compressive strength are improved. The fibers have presented a significant contribution on the shear behavior and the cracking of beams, particularly in absence of transversal bars. The waste used in this work as fibrous reinforcement has not only increased the ductility of reinforced concrete beams, but it have also provided a perfect cracking distribution on the concrete surface and it has participated in a considerable way in the reduction of cracks number and dimensions, which allows to ensure the material durability and then the structure longevity. The reinforcement of concrete beams with 0.5 % of polypropylene fibers waste with a minimal steel bars can ensure an excellent mechanical behavior in shear, as in flexion.

Evaluation on the Addition of Inhibitor and Surface Treatment to Corrosion Behavior of the Reinforced Steel Bar Embedded in Mortar Specimen

2017 ◽  
Vol 744 ◽  
pp. 114-120
Author(s):  
Kyung Man Moon ◽  
Sung Yul Lee ◽  
Jae Hyun Jeong ◽  
Myeong Hoon Lee
Keyword(s):  
Current Density ◽  
Test Specimen ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Corrosion Properties ◽  
Mortar Specimen ◽  
Steel Bar ◽  
Steel Bars ◽  
Reinforced Steel ◽  
One Year

In this study, seven types of mortar test specimens were manufactured with parameters, that is, the surface of the reinforced steel bar was treated with hot dip galvanizing (Zn) and the surface of the test specimen was coated with underwater paint, and four types of inhibitors (DAW, MCI, DCI, and Silcon) were added in mortars respectively. And, the seven types of mortar test specimens were immersed in seawater for 4 years. The corrosion properties of the reinforced steel bars embedded in mortar test specimens were investigated using electrochemical methods. The corrosion potentials of the test specimens with painting on the surface of the specimen and Zn coating on the surface of the steel bar exhibited the noblest and lowest values respectively after one year, however, after 4 years, the specimens of underwater painting and of addition of Silcon inhibitor indicated the noblest and lowest values of corrosion potentials respectively. Furthermore, the painting specimen exhibited the smallest values of corrosion probability as welll as of the corrosion current density, while, addition of MCI inhibitor showed the highest values of both corrosion probability and corrosion current density. Moreover, the painting specimen showed the smallest value of neutralization degree among all the specimens, and the largest value of neutralization degree was observed at the specimen of natural condition (no adding of inhibitor, no painting and no Zn coating). As a result, it is considered that the addition of inhibitors, coating with hot dip galvanizing (Zn), and painting on the surface have the effects not only to inhibit the neutralization degree but also to increase the corrosion resistance of the embedded steel bar.

scholarly journals Non-Destructive Investigation of a 44-Year-Old RC Structure Exposed to Actual Marine Tidal Environments Using Electrochemical Methods

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
Pinta Astuti ◽  
◽  
Khalilah Kamarulzaman ◽  
Hidenori Hamada ◽  
◽  
...  
Keyword(s):  
Visual Observation ◽  
Concrete Cover ◽  
Patch Repair ◽  
Cell Potential ◽  
Corrosion Condition ◽  
Electrochemical Tests ◽  
Rc Structure ◽  
Steel Bars ◽  
Potential Mapping ◽  
Non Destructive

Investigation of deterioration progress in marine structures without destroying them is crucial as early detection of damage before applying the suitable remedial measures. This study presents a series of non-destructive assessment on a 44-year-old naturally corroded RC structure exposed to marine tidal environments using observation of defective appearances and electrochemical tests. The visual observation was conducted by inspecting the corrosion condition of steel bars, crack patterns, and the spalling of concrete cover. The electrochemical investigations carried out in this research consisted of the half-cell potential mapping, the electrical resistivity of concrete, and the corrosion rate of steel bars. The results revealed that electrochemical test results conducted in this research were in good agreement with the actual deterioration degree checked by defective appearances. The RC structure was categorized as Grade II-1 (first half of the acceleration stage). Based on the deterioration degree, both applications of small direct current to control the potential of steel bars in immunity condition and patch repair method by removing the chloride contaminated concrete were recommended as appropriate repairing strategies, and they could extend the service life the of structure.

scholarly journals A High Precision Quality Inspection System for Steel Bars Based on Machine Vision

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2732 ◽  
Author(s):  
Xinman Zhang ◽  
Jiayu Zhang ◽  
Mei Ma ◽  
Zhiqi Chen ◽  
Shuangling Yue ◽  
...  
Keyword(s):  
Machine Vision ◽  
High Precision ◽  
Absolute Error ◽  
Detection Methods ◽  
Inspection System ◽  
Quality Inspection ◽  
Construction Site ◽  
High Definition ◽  
Steel Bar ◽  
Steel Bars

Steel bars play an important role in modern construction projects and their quality enormously affects the safety of buildings. It is urgent to detect whether steel bars meet the specifications or not. However, the existing manual detection methods are costly, slow and offer poor precision. In order to solve these problems, a high precision quality inspection system for steel bars based on machine vision is developed. We propose two algorithms: the sub-pixel boundary location method (SPBLM) and fast stitch method (FSM). A total of five sensors, including a CMOS, a level sensor, a proximity switch, a voltage sensor, and a current sensor have been used to detect the device conditions and capture image or video. The device could capture abundant and high-definition images and video taken by a uniform and stable smartphone at the construction site. Then data could be processed in real-time on a smartphone. Furthermore, the detection results, including steel bar diameter, spacing, and quantity would be given by a practical APP. The system has a rather high accuracy (as low as 0.04 mm (absolute error) and 0.002% (relative error) of calculating diameter and spacing; zero error in counting numbers of steel bars) when doing inspection tasks, and three parameters can be detected at the same time. None of these features are available in existing systems and the device and method can be widely used to steel bar quality inspection at the construction site.

scholarly journals Research on Compression Behavior of Square Thin-Walled CFST Columns with Steel-Bar Stiffeners

2018 ◽  
Vol 8 (9) ◽  
pp. 1602 ◽  
Author(s):  
Zhao Yang ◽  
Chengxiang Xu
Keyword(s):  
Bearing Capacity ◽  
Local Buckling ◽  
Steel Tube ◽  
Steel Tubes ◽  
Compression Behavior ◽  
Steel Bar ◽  
Steel Bars ◽  
Thin Walled ◽  
Structural Measure ◽  
Cfst Columns

Local buckling in steel tubes was observed to be capable of reducing the ultimate loads of thin-walled concrete-filled steel-tube (CFST) columns under axial compression. To strengthen the steel tubes, steel bars were proposed in this paper to be used as stiffeners fixed onto the tubes. Static-loading tests were conducted to study the compression behavior of square thin-walled CFST columns with steel bar stiffeners placed inside or outside the tube. The effect and feasibility of steel bar stiffeners were studied through the analysis of failure mode, load–displacement relationship, ultimate load, ductility, and local buckling. Different setting methods of steel bars were compared as well. The results showed that steel-bar stiffeners proposed in this paper can be effective in delaying local buckling as well as increasing the bearing capacity of the columns, but will decrease the ductility of the columns. In order to obtain a higher bearing capacity of columns, steel bars with low stiffness should be placed inside and steel bars with high stiffness should be placed outside of the steel tubes. The study is helpful in providing reference to the popularization and application of this new structural measure to avoid or delay the local buckling of thin-walled CFST columns.

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