scholarly journals Protection of Steel Corrosion in Concrete Members by the Combination of Galvanic Anode and Nitrite Penetration

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Minobu Aoyama ◽  
Shinichi Miyazato ◽  
Mitsunori Kawamura
Keyword(s):  
Basic Concept ◽  
Steel Corrosion ◽  
Reinforced Concrete Structures ◽  
Near Surface ◽  
Concrete Members ◽  
Chloride Induced Corrosion ◽  
Protection Method ◽  
Steel Bars ◽  
Corrosion Of Steel ◽  
Galvanic Anode

Chloride induced-corrosion of steel bars in concrete can make cracks and exfoliation in near-surface regions in reinforced concrete structures. In this paper, we described the basic concept and practice of steel bars corrosion protection method by the combination of galvanic anode (zinc wire) and the penetration of nitrite ions from mortar layers containing a large amount of lithium nitrite.

scholarly journals Relationship model between surface strain of concrete and expansion force of reinforcement rust

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fanxiu Chen ◽  
Zuquan Jin ◽  
Endong Wang ◽  
Lanqin Wang ◽  
Yudan Jiang ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Real Time ◽  
Steel Corrosion ◽  
Surface Strain ◽  
Concrete Cracking ◽  
Whole Process ◽  
Steel Bars ◽  
Relationship Model ◽  
Expansion Force ◽  
Corrosion Of Steel

AbstractConcrete cracking caused by corrosion of reinforcement could significantly shorten the durability of reinforced concrete structure. It remains critical to investigate the process and mechanism of the corrosion occurring to concrete reinforcement and establish the theoretical prediction model of concrete expansion force for the whole process of corrosion cracking of reinforcement. Under the premise of uniform corrosion of reinforcing steel bars, the elastic mechanics analysis method is adopted to analyze the entire process starting from the corrosion of steel bars to the cracking of concrete due to corrosion. A relationship model between the expansion force of corrosion of steel bars and the surface strain of concrete is established. On the cuboid reinforced concrete specimens with square cross-sections, accelerated corrosion tests are carried out to calibrate and verify the established model. The model can be able to estimate the real-time expansion force of reinforced concrete at any time of the whole process from the initiation of steel corrosion to the end of concrete cracking by measuring the surface strain of concrete. It could be useful for quantitative real-time monitoring of steel corrosion in concrete structures.

Test and Study on Impact of Corrosion on Bond Force between Steel and Concrete

2010 ◽  
Vol 36 ◽  
pp. 176-181
Author(s):  
Xian Feng He ◽  
Shou Gang Zhao ◽  
Yuan Bao Leng
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Concrete Structure ◽  
Steel Corrosion ◽  
Reinforced Concrete Structure ◽  
Bond Force ◽  
Steel Bars ◽  
Protection Layer ◽  
Corrosion Of Steel ◽  
The Impact

The corrosion of steel will have a bad impact on the safety of reinforced concrete structure. In severe cases, it may even be disastrous. In order to understand the impact of steel corrosion on the structure, tests are carried out to study corrosion and expansion rules of steel bars as well as the impact rules of corrosion on bond force between steel and concrete. The results show that wet and salty environment will result in steel corrosion; relatively minor corrosion will not cause expansion cracks of protection layers; when steel rust to a certain extent, it will cause cracks along the protection layer; when there exists minor corrosion in steel and the protection layer does not have expansion cracks, the bond force is still large and rapidly decreases as the corrosion rate increases.

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.

Corrosion Assessment and Control Techniques for Reinforced Concrete Structures

2020 ◽  
pp. 226-259
Author(s):  
Md Daniyal ◽  
Sabih Akhtar
Keyword(s):  
Reinforced Concrete ◽  
Electrochemical Techniques ◽  
Substantial Reduction ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Reinforced Concrete Structures ◽  
Steel Reinforced Concrete ◽  
Inspection Systems ◽  
Critical Requirement ◽  
Corrosion Of Steel

The steel reinforced concrete structures perform well in various environmental conditions, but structures may undergo premature damage in aggressive environments such as marine or acidic, primarily due to steel corrosion, and substantial reduction in service life occurs. This also causes huge economical loss and create safety and environmental problems. The repair and maintenance of steel reinforced concrete structures for their safety needs effective monitoring and inspection systems for evaluating the corrosion condition of steel. Since the corrosion of steel reinforcement occurs through electrochemical reactions, electrochemical methods are suitable to study the corrosion processes. In this chapter, some commonly used electrochemical techniques have been comprehensively explained. In addition, there is a critical requirement to develop effective and long-lasting techniques to control the corrosion of steel. Hence, some of the commonly used corrosion control methods have been comprehensively described in this chapter.

scholarly journals Corrosion Effect on Bond Loss between Steel and Concrete

2020 ◽  
Author(s):  
Charis Apostolopoulos ◽  
Konstantinos Koulouris
Keyword(s):  
Reinforced Concrete ◽  
Structural Integrity ◽  
Steel Corrosion ◽  
Strength Loss ◽  
Reinforcing Bar ◽  
Concrete Members ◽  
Cover Concrete ◽  
Gradual Development ◽  
Corrosion Of Steel ◽  
Bond Mechanism

This chapter is devoted to the effects of steel corrosion on bond relationship between steel and concrete. One of the basic assumptions in design of reinforced concrete members is the perfect steel - concrete bond mechanism, so that strain of reinforcing bar is the same as that of the surrounding concrete and these two different materials act as one. However, corrosion of steel reinforcement consists one of the main durability problems in reinforced concrete members, downgrade the bond behavior and therefore their structural integrity. Corrosion degrades the reinforcement itself, reducing the initial cross-section of the steel bar and its mechanical properties. Furthermore, tensile stresses in surrounding concrete caused due to oxides on the corroded reinforcement, lead to the gradual development of tensile field to the surrounding concrete, with spalling of the cover concrete and loss of bond mechanism as a consequence. In this chapter, an overview of damage of reinforced concrete due to steel corrosion is given, focused on the bond mechanism; factors that play key role in the degree of bonding and, also, proposed models of bond strength loss in correlation with the surface concrete cracking due to corrosion are indicated. To conclude, the ongoing research in this area of interest is presented, based on recent scientific studies.

Electrochemical protection against corrosion for steel bars in reinforced concrete structures exposed to seawater

2019 ◽  
pp. 185-190
Author(s):  
Yu. L. Kuzmin ◽  
O. A. Stavitsky
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Structures ◽  
Offshore Structures ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structures ◽  
Marine Structures ◽  
Electrochemical Protection ◽  
Steel Bars ◽  
Corrosion Of Steel

The paper analyzes ways to ensure long service life (up to 50 years) of reinforced concrete marine structures. It has been established that durability and maintenance-free operation of floating and coastal offshore structures for 50 and more years depend on corrosion of steel reinforcement which could be avoided by applying electrochemical protection. The parameters of electrochemical protection against corrosion of steel fittings are given.

scholarly journals Torsional Strengthening of RC Beams with Near-Surface Mounted Steel Bars

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Nasih Habeeb Askandar ◽  
Abdulkareem Darweesh Mahmood
Keyword(s):  
Twist Angle ◽  
Bending Moment ◽  
Rc Beams ◽  
Near Surface ◽  
Concrete Members ◽  
Epoxy Adhesives ◽  
Steel Bars ◽  
Externally Bonded ◽  
Near Surface Mounted ◽  
Combined Actions

The strength of reinforced concrete members can be enhanced by using the externally bonded reinforcement (EBR) and near-surface mounted (NSM) methods. However, very few studies have adopted the NSM method for torsional strengthening. Although previous studies have reported the efficacy of using epoxy-resin-bonded NSM steel bars in increasing the flexural and shear strength of RC beams, no study has examined the use of steel bars and epoxy adhesives for torsional strengthening. Therefore, this study investigates the behaviour of RC beams subjected to the combined actions of torsion and bending moment when they are strengthened with NSM steel bars (Ø10 mm) in different configurations. The practical part of this investigation consisted of seven cast and tested beams of 150 × 250 × 2000 mm dimensions. One beam was reference, which is not strengthened; meanwhile, all the other beams were strengthened with two U-shape-welded NSM steel bars. During the testing process, the twist angle at the torque intervals, first cracking torque, ultimate torque, and ultimate twist angle of the conventional beam were compared with those of the strengthened beams. The torsional performance of the RC beams was significantly improved by using NSM steel bars, whereas in various NSM configurations, the 90° NSM beams outperformed the 45° NSM beams.

scholarly journals Towards arresting reinforced concrete corrosion – a review

2018 ◽  
Vol 199 ◽  
pp. 05001
Author(s):  
Christian Christodoulou ◽  
Chris Goodier ◽  
Gareth Glass
Keyword(s):  
Reinforced Concrete ◽  
Solid Phase ◽  
Steel Corrosion ◽  
Corrosion Damage ◽  
Sacrificial Anodes ◽  
Corrosion Initiation ◽  
Chloride Induced Corrosion ◽  
Corrosion Risk ◽  
Corrosion Of Steel ◽  
Reinforced Concrete Corrosion

This work reviews developments in the understanding of chloride induced corrosion of steel in concrete from both a kinetic and thermodynamic perspective. Corrosion damage is at least in part attributed to the production of acid at sites of corrosion initiation. Solid phase inhibitors provide a reservoir of hydroxyl ions to inhibit damage. Pit re-alkalisation is identified as an important protective effect in electrochemical treatments used to arrest corrosion. A process like pit re-alkalisation is achieved more easily by impressing current from sacrificial anodes using a power supply which may then be followed by low maintenance galvanic protection to prevent local acidification. Methods for monitoring the steel corrosion rate in electrochemically treated reinforced concrete have been developed and used to assess corrosion risk. Some of these concepts have been adopted in the recent international standard on cathodic protection, ISO 12696:2016, some of the amendments of which are considered in the work presented here.

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