scholarly journals THE PROPERTIES OF PITTING CORROSION OF STEEL REINFORCEMENT OF REINFORCED CONCRETE BEAMS

2017 ◽  
Vol 2 (3) ◽  
pp. 32-36
Author(s):  
Дронов ◽  
Andrey Dronov
Keyword(s):  
Reinforced Concrete ◽  
Pitting Corrosion ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Reinforced Concrete Structures ◽  
Damage Distribution ◽  
Chloride Environment ◽  
Corrosion Of Steel

Two types of steel reinforcement depassivation process: carbonation of concrete and chloride penetration are considered in the article. The comparison between the corrosion due to carbonation of concrete and the chloride-induced corrosion was carried out. It was found out, that chlorides induced corrosion is potentially more dangerous than that resulting from carbonation. Method of durable tests of reinforced concrete structures under the action of the gravitational load and the corrosive chloride environment is described in the article. The results of experimental research on reinforced concrete structures with corrosive damages to steel reinforcement are given in the article. The properties of corrosion cracking in the case of the pitting corrosion were determined. The character of corrosive damage distribution along the reinforcement bars and its effect on the strength of reinforced concrete beams were determined.

DEVELOPMENT OF EMBEDDED MINI-SENSOR FOR DIAGNOSIS OF CORROSION OF STEEL REINFORCEMENT IN CONCRETE NONDESTRUCTIVELY

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Mohamed A. Ismail ◽  
Han-Seung Lee ◽  
Mohd Warid Hussin
Keyword(s):  
Reinforced Concrete ◽  
Polarization Resistance ◽  
Concrete Structures ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structures ◽  
Chloride Ingress ◽  
Reinforcement Corrosion ◽  
Maintenance And Rehabilitation ◽  
Corrosion Of Steel ◽  
Non Destructive

Corrosion of steel reinforcement embedded in concrete is one of the main causes of degradation of reinforced concrete structures. Degradation occurs in reinforced concrete structures from corrosion caused by the Chloride ingress into concrete. That degradation has a severe impact on the structure in terms of maintenance and rehabilitation costs. Therefore, early detection of reinforcement corrosion is important for efficient maintenance, repair and planning. Meanwhile, the evaluation of the corrosion of reinforcement by non-destructive measurements have been used a lot. In particular CM-II (corrosion meter) is used to measure the polarization resistance, but has some disadvantages. Embedded mini-sensor has been developed in order to overcome these disadvantages. In this study, measurement of corrosion by using the mini-sensor is compared with the measured results by CM-II to verify the validity of the newly developed mini senor. Results show that there are agreement in trends of the parameters measured and as such the developed mini sensor has a promising start to be used.

Non-Destructive Vibration Tests on Reinforced Concrete Structures

2015 ◽  
Vol 660 ◽  
pp. 186-191 ◽  
Author(s):  
Marina Lute
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Response ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Reinforced Concrete Beams ◽  
Reinforced Concrete Structures ◽  
Linear Behavior ◽  
Non Linear ◽  
Vibration Tests ◽  
Non Destructive

The purpose of this paper is looking at the dynamic response of existing reinforced concrete structures which have possibly sustained various levels of damage, a set of tests need to be identified that will be able to detect damage and quantify the damage if damage exists. In this work it is presented a further study on the effect of damage on the behavior of reinforced concrete beams. In particular, the non-linear behavior of these beams is considered once significant cracking has been introduced, outlining the stage of testing carried out in dynamic field.

scholarly journals Calculation of damage RC constructions according to deformation model

2020 ◽  
Vol 2020 (2) ◽  
pp. 99-106
Author(s):  
Yaroslav Blikharskyy ◽  
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Physical And Mechanical Properties ◽  
Reinforced Concrete Beams ◽  
Core Material ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
The Impact

This article presents results of a theoretical study of reinforced concrete beams with damaged reinforcement. The change of micro-hardness of a reinforcing rebar’s with a diameter of 20 mm of A500C steel in the radial direction is investigated and the thickness of the heat-strengthened layer is established. It is established that the thickness of the thermo-strengthened steel layer of the reinforcing bar with a diameter of 20 mm of A500C is approximately 3 mm. It is shown that the strength characteristics of this layer are on 50% higher compared to the core material of the rebar, while the plasticity characteristics are lower. The aim of the work is to determine the strength and deformability of reinforced concrete structures without damaging the reinforcement and in case of damage. Determining the impact of changes in the physical characteristics of reinforcement on the damage of reinforced concrete structures, according to the calculation to the valid norms, in accordance with the deformation model. To achieve the goal of the work, theoretical calculations of reinforced concrete beams were performed according to the deformation model, according to valid norms. This technique uses nonlinear strain diagrams of concrete and rebar and is based on an iterative method. According to the research program 3 beam samples were calculated. Among them were undamaged control sample with single load bearing reinforcement of ∅20 mm diameter – BC-1; sample with ∅20 mm reinforcement with damages about 40% without changes in the physical and mechanical properties of reinforcement – BD-2 and sample with ∅20 mm reinforcement with damages about 40% with changes in the physical and mechanical properties of reinforcement – BD-3. The influence of change of physical and mechanical characteristics of rebar’s on bearing capacity of the damaged reinforced concrete beams is established.

scholarly journals Influence of PVC Fiber Reinforcement on Shear Strength in Concrete Beams

2019 ◽  
Vol 7 (1) ◽  
pp. 34-43
Author(s):  
Kadhim Zuboon Nasser ◽  
Ali Abdulhasan Khalaf ◽  
Fadhil K. Idan
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Concrete Structures ◽  
Fiber Reinforcement ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Shear Reinforcement ◽  
Time Service ◽  
Before And After

This study adopted the investigation of the effect of a material that can be used as an alternative to steel reinforcement of shear in reinforced concrete beams, as the most susceptible to corrosion to which reduces the time service of the concrete structures and increase the maintenance costs is the steel reinforcement of shear for the closeness of surface of concrete. Therefor non-corroding material is needful for concrete structures and PVC fiber reinforcement is chosen. Experimentally nine reinforced concrete beams have been tested to determine the effect of PVC fiber reinforcement on the concrete beam resistance load, the load of cracks, deflection achieved and distribution with dimension of cracks. Three volume fraction ratios were taken for PVC fiber reinforcement (0, 0.25 and 0.5), which were identical to the shear reinforcement used in this research (0,0.29 and 0.54). All the concrete beams were tested with in on one program by applied a center load from the top in the middle to the failure load and the results were impressive. The specimens containing the PVC fiber reinforcement percentages achieved a remarkable increase in the crack and ultimate load of the concrete beams before and after cracks with direct effect in changing the failure type. While the deflection achieved due to the increase in PVC fiber percentage is more than the allowable deflection in the ACI Code equations of the reinforced concrete beams and more of these if the use of PVC fiber and steel reinforcement of shear together. A smaller measurement of the maximum cracks width was achieved by using advanced percentages of PVC fiber and shear reinforcement (0.5 and 0.54) respectively.

scholarly journals DEFLECTION OF FLEXURAL REINFORCED CONCRETE STRUCTURES WITH EXTERNAL NON-METALLIC REINFORCEMENT (EXPERIMENTAL AND THEORETICAL INVESTIGATION)

2002 ◽  
Vol 8 (3) ◽  
pp. 164-168
Author(s):  
Juozas Valivonis
Keyword(s):  
Reinforced Concrete ◽  
Theoretical Investigation ◽  
Concrete Beams ◽  
Theoretical Calculations ◽  
Concrete Structures ◽  
Reinforced Concrete Beams ◽  
Experimental Investigations ◽  
Reinforced Concrete Structures ◽  
Metallic Reinforcement ◽  
Good Agreement

In many cases concrete structures with prestressed steel being sufficiently strong do not meet requirements for stiffness. It is possible to avoid steel prestressing in concrete structures by means of providing additional non-metallic reinforcement, which gives opportunity to increase stiffness of beams significantly. Experimental investigations of reinforced concrete beams with external non-metallic reinforcement were made. Method for calculation of deflection of beams with external non-metallic reinforcement is presented in this article. Theoretical calculations of deflections using the proposed method were performed. Sufficiently good agreement with experimental deflection values was obtained.

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.

Reinforcement Corrosion versus Crack Width

2014 ◽  
Vol 897 ◽  
pp. 161-164
Author(s):  
Peter Kotes ◽  
Ján Kozák
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Construction Material ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Reinforcement Corrosion ◽  
Materials Selection ◽  
Resistant Material ◽  
Corrosion Of Steel ◽  
Design Construction

Reinforced concrete is a versatile, economical and successful construction material. Usually, it is durable and resistant material, performing well throughout its service life. However, sometimes it does not perform adequately as it is expected. It is due to poor design, construction, inadequate materials selection and more severe environment than anticipated or a combination of those factors [1, . The reinforcement corrosion is the phenomenon that highly affects the reliability and durability of reinforced concrete structures. From that reason, a lot of researchers in Slovakia and in the world pay their attention to reinforcement corrosion. The paper is concerned with detection and simulation of corrosion of steel reinforcement in the reinforced concrete. The cracking response of the reinforced concrete beams due to the corrosion effect of the steel reinforcement was analyzed. The effect of corrosion was simulated by the nonlinear numerical analysis using the program ATENA.

Detecting the Extent of Corrosion with Acoustic Emission

2000 ◽  
Vol 1698 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Dong-Jin Yoon ◽  
W. Jason Weiss ◽  
Surendra P. Shah
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Load Level ◽  
Reinforced Concrete Beams ◽  
Parameter Analysis ◽  
Reinforced Concrete Structures ◽  
Damage Level ◽  
Ae Signal

Reinforced concrete beams were tested in flexure, and their acoustic emission (AE) response was recorded. This research was performed to investigate the characteristic AE response that is associated with microcrack development, localized crack propagation, corrosion, and debonding of the reinforcing steel in an attempt to use AE to characterize the source of damage. Concrete beams were prepared to isolate these damage mechanisms by using unreinforced, notched-unreinforced, reinforced, and corroded-reinforced specimens. The AE response was analyzed to obtain key parameters such as the total number and rate of AE events, the amplitude and duration of the events, and the characteristic features of the waveform. Initial analysis of the AE signal has shown that a difference in the AE response can be observed depending on the source of the damage. By plotting the AE signal amplitude versus duration (cross-plot), it can be seen that distributed microcracking is typically characterized by a relatively low amplitude and short duration, whereas debonding cracks have a higher amplitude and longer duration. The Felicity ratio (ratio of the load level at which AE activity begins to occur and the previous loading level) exhibits a favorable correlation with the overall damage level, and the total number of AE events that occur during unloading may provide an effective criterion for estimating the level of corrosion distress in reinforced concrete structures. Based on these results, AE parameter analysis may provide a promising approach for estimating the level of damage and corrosion distress in reinforced concrete structures.

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