Numerical Interpretation of Bond Between Steel and Concrete in Presence of Corrosion and Cyclic Action

2009 ◽  
Vol 417-418 ◽  
pp. 349-352 ◽  
Author(s):  
Luca Giordano ◽  
Giuseppe Mancini ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Stress Transfer ◽  
Experimental Tests ◽  
Radial Pressure ◽  
Mechanical Action ◽  
Concrete Cover ◽  
Reinforcing Bars ◽  
Cyclic Action ◽  
Bond Slip

Bond between steel and concrete in reinforced concrete structures plays a fundamental role. The stress transfer mechanism depends on the condition of the contact surface between the two materials, the mechanical characteristics of concrete near the rebar and on the available level of confinement. Corrosion of reinforcing bars in concrete structures modifies those three factors. Because of corrosion, on the rebar surface a granular oxide layer is present and with its expansion it generates a significant radial pressure; consequently tensile stresses grow till cracking of the concrete cover with a subsequent reduction of the confinement effect. Moreover the presence of a mechanical action modifies the resisting mechanism producing an increasing damage. In this study, a model is presented for the numerical simulation of experimental tests on r.c. ties subjected to mechanical action; furthermore some considerations on reinforced concrete ties subjected also to corrosion effect are reported. From those analyses it is possible to estimate a modified bond-slip law between the reinforcing bars and the concrete, in order to take into account the level of damage.

Effect of Chloride-Induced Steel Corrosion on Working Life of Concrete Structures

2018 ◽  
Vol 272 ◽  
pp. 226-231 ◽  
Author(s):  
Ivan Hollý ◽  
Juraj Bilčík
Keyword(s):  
Pore Solution ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Radial Pressure ◽  
Concrete Cover ◽  
Transport Infrastructure ◽  
Reinforcing Bars ◽  
Volume Increase ◽  
Volumetric Expansion ◽  
High Alkalinity

The reinforcing steel embedded in concrete is generally protected against corrosion by the high alkalinity (pH = 12.5 to 13.5) of the concrete pore solution. The structural degradation of concrete structures due to reinforcement’s corrosion has an impact on the safety, serviceability and durability of the structure. The corrosion of reinforcements in the construction of a transport infrastructure (especially bridges), parking areas, etc., is primarily initiated by chlorides from de-icing salts. When corrosion is initiated, active corrosion results in a volumetric expansion of the corrosion products around the reinforcing bars against the surrounding concrete. Reinforcement corrosion causes a volume increase due to the oxidation of metallic iron, which is mainly responsible for exerting the expansive radial pressure at the steel–concrete interface and development of hoop tensile stresses in the surrounding concrete. When this tensile stress exceeds the tensile strength of the concrete, cracks are generated. Higher corrosion rates can lead to the cracking and spalling of the concrete cover. Continued corrosion of reinforcement causes a reduction of total loss of bond between concrete and reinforcement.

Experimental Evaluation of Corrosion Effect on Bond Between Steel and Concrete in Presence of Cyclic Action

2009 ◽  
Vol 417-418 ◽  
pp. 345-348 ◽  
Author(s):  
Luca Giordano ◽  
Giuseppe Mancini ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Load ◽  
Crack Opening ◽  
Concrete Structures ◽  
Electrochemical Corrosion ◽  
Reinforced Concrete Structures ◽  
Reinforcing Bars ◽  
Cyclic Action ◽  
In Series ◽  
Ultimate Condition

Corrosion modifies the steel-concrete interface in reinforced concrete structures. The efficiency of the connection between the two materials is reduced and the structural behavior both in service and in ultimate condition is affected. Moreover in structures subjected to cyclic load, a simultaneous mechanical deterioration due to the load is present. In this work an experimental analysis on reinforced concrete structures under both cyclic load and corrosion of reinforcing bars is presented. Three couples of reinforced concrete ties are connected in series and subjected to the same stress variation in order to produce the cracking conditions and to activate the bond mechanism. However, while one of the two reinforced concrete ties is only subjected to cyclic load, the second one is also corroded using an accelerated electrochemical corrosion process. The simultaneous effect of the cyclic load and corrosion is evaluated monitoring the crack opening on the structures during the test and by means of visual inspection of the sample. The test results show the correlation between the mechanism of bond and the average level of stresses for an amplified stress range.

Passive corrosion control and active corrosion prevention of the reinforced concrete structures by electrochemical chloride removal and inhibitors

2013 ◽  
Vol 61 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Guofu Qiao ◽  
Yi Hong ◽  
Tiejun Liu ◽  
Jinping Ou
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Corrosion Control ◽  
Cell Potential ◽  
Content Type ◽  
Chloride Removal ◽  
Active Corrosion

Purpose – The aim of this paper was to investigate the passive corrosion control and active corrosion protective effect of the reinforced concrete structures by electrochemical chloride removal (ECR) method and inhibitors approach, respectively. Design/methodology/approach – The concentration of aggressive chloride ion distributed from the reinforcing steel to the surface of the concrete cover was analyzed during the ECR processes. Besides, the half-cell potential, the concrete resistance R c , the polarization resistance R p and the capacitance of double layer C dl of the steel/concrete system were used to characterize the electrochemical performance of the concrete prisms. Findings – The effectiveness of ECR could be enhanced by increasing the amplitude of potential or prolonging the time. Inhibitor SBT-ZX(I) could successfully prevent the corrosion development of the reinforcing steel in concrete. Originality/value – The research provides the scientific basis for the practical application of ECR and inhibitors in the field.

scholarly journals Comparison of the stress-strain state of the reinforced concrete structure under various mathematical models of concrete

2018 ◽  
Vol 251 ◽  
pp. 04032
Author(s):  
Dmitriy Sidorov ◽  
Vladimir Dorozhinskiy
Keyword(s):  
Reinforced Concrete ◽  
Mathematical Models ◽  
Strain State ◽  
Concrete Structures ◽  
Seismic Action ◽  
Reinforced Concrete Structure ◽  
Reinforcing Bars ◽  
Plastic Deformations ◽  
Regulatory Documents ◽  
Structural Engineer

Nowadays, reinforced concrete structures are most often used as load-bearing elements of buildings and structures. In the case of alternating loads such as seismic action, there is accumulation of residual plastic deformations in the concrete structures, which leads to a significant complication in the calculation of structures by “standard” methods. For such problems, it is advisable to use computational complexes in which mathematical models of structural materials are implemented, which allow to describe the work of concrete and reinforcing bars for various types of impacts more properly. However, when applying such methods, the results obtained should not contradict the requirements of the existing regulatory documents, which, in the first place, the structural engineer should be guided by. Before solving more complex problems, the applied methods should be verified and analyzed for fairly simple structures and types of loads.

scholarly journals Experimental Study on Bond Performance and Damage Detection of Corroded Reinforced Concrete Specimens

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yubin Tian ◽  
Junran Liu ◽  
Hengheng Xiao ◽  
Yi Zhang ◽  
Qingcheng Mo ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Coefficient ◽  
Concrete Cover ◽  
Empirical Formulas ◽  
Accelerated Corrosion ◽  
Bond Slip ◽  
Passivation Film ◽  
Bond Performance ◽  
Damage Degree ◽  
Cover Thickness

This paper presents the results of an experimental research designed to investigate the combined effects of corrosion rate, concrete cover thickness, and stirrup spacing on the bond performance between reinforcement and concrete of reinforced concrete (RC) specimens. The RC specimens were immersed into sodium chloride solution to eliminate the passivation film on reinforcement. Then, an accelerated corrosion method was applied to corrode reinforcement embedded in concrete specimens. Pullout test was carried out to establish empirical formulas for ultimate slip and ultimate bond strength of RC specimens with three different corrosion rates, different concrete cover thicknesses, and different stirrup spacings. In addition, the bond-slip relation model was developed to predict and evaluate the bond performance of RC specimens. Finally, the ultrasonic technology was used to detect the damage of RC specimens, and the corresponding nonlinear coefficient β was proposed to characterize the damage degree of RC specimens. The susceptibility of β on the damage of specimens was compared with that of ultrasonic velocity, indicating β was more appropriate to evaluate the damage of RC specimens.

Investigation of bond between fibre-reinforced polymer bars and concrete under sustained loads

2006 ◽  
Vol 33 (11) ◽  
pp. 1426-1437 ◽  
Author(s):  
F Shahidi ◽  
L D Wegner ◽  
B F Sparling
Keyword(s):  
Reinforced Concrete ◽  
Sustained Load ◽  
Reinforcing Bars ◽  
Bond Slip ◽  
Reinforced Polymer ◽  
Sustained Loads ◽  
Fibre Reinforced Polymer ◽  
Term Performance ◽  
Frp Bars

Although the use of fibre-reinforced polymer (FRP) bars to replace steel in reinforced concrete is becoming more common, uncertainty remains concerning the long-term performance of FRP, including the effect of a sustained load on the bond between the FRP bars and the concrete. An experimental study was therefore undertaken to investigate the long-term durability of the bond for various types of bars embedded in concrete: one type of glass FRP, two types of carbon FRP, and conventional steel reinforcing bars. Pullout specimens were tested both statically to failure and under sustained loads for periods of up to 1 year while free-end slip was monitored. Results revealed lower short-term bond strengths for FRP bars relative to steel and significant variability in long-term bond-slip performance among FRP bars of different types. Post-testing investigations revealed damage to bar surfaces at the macroscopic level, as well as broken longitudinal fibres and damage to the surface coatings at the microscopic level.Key words: reinforced concrete, fibre-reinforced polymer (FRP), bond, creep, pullout, sustained loads.

scholarly journals Bearing capacity of RC beams reinforced with high strength rebars and steel plate

2018 ◽  
Vol 230 ◽  
pp. 02003 ◽  
Author(s):  
Taras Bobalo ◽  
Yaroslav Blikharskyy ◽  
Rostyslav Vashkevich ◽  
Myhailo Volynets
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Steel Plate ◽  
Concrete Structures ◽  
High Strength ◽  
Strength Properties ◽  
Rc Beams ◽  
Reinforcing Bars ◽  
External Reinforcement ◽  
Effective Use

Nowadays, reducing the material content of not only buildings and structures in general, but also individual constructions is a topical task that can be realized through the use of high-strength concrete and reinforcement, as well as with the use of external reinforcement. The concentrated location of sheet reinforcement on the external the most tense facets of steel and concrete structures increases the operating height of the cross-section, makes it possible to more effectively use the strength properties of steel in comparison with conventional reinforced concrete, and with the same bearing capacity to economize on expenses. Composite and monolithic reinforced concrete structures with external reinforcement are used in various construction sectors around the world. This contributed to the expansion of the use of reinforced concrete for special buildings of power-engineering and hydrotechnical construction. The technical nd econom efficiency, as well as the possibility of using external rebar as formwork for monolithic concrete construction, have been proved. Therefore, there is a need for the study of structures with combined reinforcement, in which high rigidity of steel and concrete structures is combined with an effective use of high-strength reinforcing bars (rebar) without prior tension

Modeling bond-slip deformations in reinforced concrete beam-column joints

2000 ◽  
Vol 27 (3) ◽  
pp. 490-505 ◽  
Author(s):  
Mostafa Elmorsi ◽  
M Reza Kianoush ◽  
W K Tso
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Element Model ◽  
Reinforced Concrete Beam ◽  
Experimental Results ◽  
Reinforcing Bars ◽  
Bond Slip ◽  
Joint Element ◽  
Column Joint

A new finite element model for reinforced concrete beam-column joints is proposed. The model considers the effects of bond-slip and shear deformations in the joint panel region. The problems associated with modeling bond-slip of anchored reinforcing bars are discussed. The proposed bond-slip model is examined at the element level by comparing its predictions with other analytical and experimental results. The ability of the model to simulate bond deterioration and eventual pullout of anchored reinforcing bars under severe cyclic excitation is demonstrated. This model is incorporated into the global beam-column joint element. Further comparisons are made between the predictions of the proposed beam-column joint model and other analytical and experimental results under reversed cyclic loading to show the validity of the model to describe the bond-slip behavior of the joints.Key words: bond, bond-slip, finite element, beam-column, reinforced concrete, cyclic.

Sign in / Sign up

Export Citation Format

Share Document