scholarly journals Bond Behavior of Reinforced Concrete Considering Freeze–Thaw Cycles and Corrosion of Stirrups

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4732
Author(s):  
Shuo Liu ◽  
Maohua Du ◽  
Yubin Tian ◽  
Xuanang Wang ◽  
Guorui Sun
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Bond Strength ◽  
Mechanical Performance ◽  
Element Analysis ◽  
Freeze Thaw ◽  
Bonding Performance ◽  
Pull Out ◽  
Steel Bar

In relatively cold environments, the combination of freeze–thaw and steel bar corrosion is a key factor affecting the durability of concrete. The adjustment of the stirrup ratio would change the mechanical performance of surrounding concrete, while the circumferential compressive stress can further improve the bonding performance. Hence, based on eccentrically tensioned specimens, the influence of corrosion of stirrups and freeze–thaw of concrete on bond properties is discussed in this paper. The monotonic pull-out test of reinforced concrete specimens is carried out to study the variation rules of bond strength and slip between steel bar and concrete under the coupling action of corrosion rate, freeze–thaw times and stirrup spacing. Based on the experimental data, the empirical formula for the ultimate bond strength is obtained, and a bond–slip constitutive model is established considering the stirrup spacing, stirrup corrosion rate and freeze–thaw times. Then, a refined finite element pull-out specimen model is established by ABAQUS simulation, and the numerical simulation results are compared with the real test ones, so as to make up for the deficiencies in the test and lay the foundation for further finite element analysis.

scholarly journals The Effect of Freeze-Thaw Damage on Corrosion in Reinforced Concrete

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Xiao-Chun Lu ◽  
Bin Guan ◽  
Bo-Fu Chen ◽  
Xin Zhang ◽  
Bo-bo Xiong
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Sem Analysis ◽  
Steel Reinforcement ◽  
Reinforcement Corrosion ◽  
Freeze Thaw ◽  
Pull Out ◽  
Thaw Cycle ◽  
Corrosion Reaction ◽  
Freeze Thaw Cycle

The existing studies of the corrosion of reinforced concrete have mainly focused on the interface area and chemical ion erosion, ignoring the specific service environment of the reinforced concrete. In this study, the effect of freeze-thaw damage was investigated via corrosion experiments under different freeze-thaw cycle conditions. Steel reinforcement corrosion mass, ultimate pull-out force, corrosion rate, and bond slippage were chosen as characteristic parameters in the experiments, and scanning electron microscopy (SEM) analysis was used to explain the mechanism of action of freeze-thaw damage on corrosion. The results showed that, under identical corrosion conditions, the mass of steel reinforcement corrosion and corrosion rate increased by 39.6% and 39.7% when comparing 200 freeze-thaw cycles to 0 cycles, respectively. The ultimate pull-out force and bond slippage after 200 freeze-thaw cycles decreased by 73% and 31%, respectively, compared with 0 freeze-thaw cycles. In addition, SEM analysis indicated that microstructure damage caused by freeze-thaw cycles accelerated the corrosion reaction and decreased cementitious properties, leading to decreasing ultimate pull-out force and bond slippage. The effect of freeze-thaw cycles and steel reinforcement corrosion on the macro mechanical properties of concrete is not a simple superposition.

scholarly journals Experimental and Numerical Investigation of Bond-Slip Behavior of High-Strength Reinforced Concrete at Service Load

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 293
Author(s):  
Alinda Dey ◽  
Domas Valiukas ◽  
Ronaldas Jakubovskis ◽  
Aleksandr Sokolov ◽  
Gintaris Kaklauskas
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Numerical Investigation ◽  
Load Level ◽  
Scale Model ◽  
Element Analysis ◽  
Bond Slip ◽  
Pull Out ◽  
Bond Mechanism ◽  
Concrete Interface

A bond mechanism at the reinforcement-concrete interface is one of the key sources of the comprehensive functioning of reinforced concrete (RC) structures. In order to apprehend the bond mechanism, the study on bond stress and slip relation (henceforth referred as bond-slip) is necessary. On this subject, experimental and numerical investigations were performed on short RC tensile specimens. A double pull-out test with pre-installed electrical strain gauge sensors inside the modified embedded rebar was performed in the experimental part. Numerically, a three dimensional rib scale model was designed and finite element analysis was performed. The compatibility and reliability of the numerical model was verified by comparing its strain result with an experimentally obtained one. Afterwards, based on stress transfer approach, the bond-slip relations were calculated from the extracted strain results. The maximum disparity between experimental and numerical investigation was found as 19.5% in case of strain data and 7% for the bond-slip relation at the highest load level (110 kN). Moreover, the bond-slip curves at different load levels were compared with the bond-slip model established in CEB-fib Model Code 2010 (MC2010). Overall, in the present study, strain monitoring through the experimental tool and finite element modelling have accomplished a broader picture of the bond mechanism at the reinforcement-concrete interface through their bond-slip relationship.

scholarly journals Experimental Research and Simulation on the Mechanical Performance Degradation of Corroded Stud Shear Connectors

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Bing Wang ◽  
Xiaoling Liu ◽  
Jiantao Du
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Corrosion Rate ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Tensile Behavior ◽  
Uniaxial Tensile ◽  
Element Analysis ◽  
Gtn Model

Electrochemical accelerated corrosion and tensile tests were conducted on six series of 30 stud specimens in this study to assess the various mechanical properties in corroded stud connectors. The results indicate that there is a gradual decline in mechanical properties (e.g., yield strength, ultimate strength, and plasticity) as stud corrosion rate increases. Degradation equations for these parameters were established via fitting analysis on the test data. A Gurson–Tvergaard–Needleman (GTN) constitutive model describing the tensile behavior of corroded studs was established based on mesodamage mechanics and finite element analysis. In the GTN model, the corrosion rate equals the original void volume fraction; the trial-and-error method was adopted to determine the relationship between the corrosion rate and material failure parameters. The finite element simulation results are in good agreement with the experimental results. The GTN model accurately simulates the uniaxial tensile behavior of the corroded stud.

Bond Behaviors between Polymer Cement Coated Steel Bar Subjected to Environmental Action and Concrete

2016 ◽  
Vol 711 ◽  
pp. 1105-1110
Author(s):  
Yuan Liang Xiong ◽  
Kun Rong Wang ◽  
Zhi Yong Liu
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Failure Modes ◽  
Environmental Action ◽  
Chloride Ingress ◽  
Coated Steel ◽  
Pull Out ◽  
Uncoated Steel ◽  
Steel Bar ◽  
Steel Bars

The bond behaviors (failure modes, bond strength, bond stress slip curves) between steel bars coated with polymer modified cement-based coating and concrete as well as effect of carbonation and chloride ingress on the bond behaviors were studied in this paper. Twenty-four concentrically reinforced concrete cubes were cast and pull-out tests under monotonic loading were carried out. The results indicated that the polymer modified cement-based coating can be well bonded with steel bar and the failure mode of all the specimens is splitting. The typical polymer cement-based coating could enhance the bond strength slightly of the uncoated steel bar with concrete in this experiments. But the bond strength were all depressed between the coated steel bars subjected to carbonation and chloride ingress and concrete.

Finite Element Analysis of the Corrosion Prestressed Concrete Beam

2012 ◽  
Vol 204-208 ◽  
pp. 3040-3043
Author(s):  
Hong Bo Zou ◽  
Xiao Yong Luo
Keyword(s):  
Finite Element ◽  
Corrosion Rate ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Element Model ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Prestressed Concrete Beam

Based on analysis of the Corrosion prestressed concrete beam with finite element model, the paper presents the mechanical performance of concrete beams in different corrosion rates. When the corrosion rate is less than 5%, the strand corrosion has little impact on the load capacity. With the increase of the corrosion rate more than 5%, what damage happened to Beam is little steel damage and brittle damage even without apparent warning and at the same time the Corrosion of steel strand will cause the decrease of the ultimate load capacity with the deterioration of ductility.

scholarly journals Analytical modeling of the contact pressure at the steel-concrete interface

2021 ◽  
Author(s):  
Sini Bhaskar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Contact Pressure ◽  
Analytical Model ◽  
Concrete Member ◽  
Element Analysis ◽  
Pull Out ◽  
Reinforced Concrete Member ◽  
Concrete Interface

This research studies the effect of corrosion on bond strength at the steel-concrete interface in a reinforced concrete member. Bond stress, which can be defined as the shear stress which develops along the lateral surface of the bar, is expressed as a function of contact pressure at the steel-concrete interface. An analytical model of bond which describes the contact pressure between the reinforcing bar and concrete in a reinforced concrete member is developed. The expression for the reduction in contact pressure due to the accumulation of corrosion products is then developed using the model developed for the uncorroded reinforcing steel bar. The developed analytical model was implemented in a finite element analysis, which was conducted using ABAQUS, of pull-out specimens conducted by Amleh (2000). A reasonable good agreement between the experimental and finite element analysis results was obtained.

scholarly journals Structural Effects of Reinforced Concrete Beam Due to Corrosion

2018 ◽  
Vol 34 ◽  
pp. 01024
Author(s):  
Hamidun Mohd Noh ◽  
Nur’ain Idris ◽  
Nurazuwa Md Noor ◽  
Norliana Sarpin ◽  
Rozlin Zainal ◽  
...  
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Quantitative Relation ◽  
Interface Element ◽  
Structural Effects ◽  
Element Analysis ◽  
Worst Case

Corrosion of steel in reinforced concrete is one of the main issues among construction stakeholders. The main consequences of steel corrosion include loss of cross section of steel area, generation of expansive pressure which caused cracking of concrete, spalling and delaminating of the concrete cover. Thus, it reduces the bond strength between the steel reinforcing bar and concrete, and deteriorating the strength of the structure. The objective of this study is to investigate the structural effects of corrosion damage on the performance of reinforced concrete beam. A series of corroded reinforced concrete beam with a corrosion rate of 0%, 20% and 40% of rebar corrosion is used in parametric study to assess the influence of different level of corrosion rate to the structural performance. As a result, the used of interface element in the finite element modelling predicted the worst case of corrosion analysis since cracks is induced and generate at this surface. On the other hand, a positive linear relationship was sketched between the increase of expansive pressure and the corrosion rate. Meanwhile, the gradient of the graph is decreased with the increase of steel bar diameter. Furthermore, the analysis shows that there is a significant effect on the load bearing capacity of the structure where the higher corrosion rate generates a higher stress concentration at the mid span of the beam. This study could predict the residual strength of reinforced concrete beam under the corrosion using the finite element analysis. The experimental validation is needed on the next stage to investigate the quantitative relation between the corrosion rate and its influence on the mechanical properties.

scholarly journals Analytical modeling of the contact pressure at the steel-concrete interface

2021 ◽  
Author(s):  
Sini Bhaskar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Contact Pressure ◽  
Analytical Model ◽  
Concrete Member ◽  
Element Analysis ◽  
Pull Out ◽  
Reinforced Concrete Member ◽  
Concrete Interface

This research studies the effect of corrosion on bond strength at the steel-concrete interface in a reinforced concrete member. Bond stress, which can be defined as the shear stress which develops along the lateral surface of the bar, is expressed as a function of contact pressure at the steel-concrete interface. An analytical model of bond which describes the contact pressure between the reinforcing bar and concrete in a reinforced concrete member is developed. The expression for the reduction in contact pressure due to the accumulation of corrosion products is then developed using the model developed for the uncorroded reinforcing steel bar. The developed analytical model was implemented in a finite element analysis, which was conducted using ABAQUS, of pull-out specimens conducted by Amleh (2000). A reasonable good agreement between the experimental and finite element analysis results was obtained.

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