scholarly journals Influence of Freeze-Thaw Damage on the Steel Corrosion and Bond-Slip Behavior in the Reinforced Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Fangzhi Zhu ◽  
Zhiming Ma ◽  
Tiejun Zhao
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Bond Slip ◽  
Freeze Thaw ◽  
Ordinary Concrete ◽  
Air Entrained Concrete

This paper mainly studies the behavior of steel corrosion in various reinforced concrete under freeze-thaw environment. The influence of thickness of concrete cover is also discussed. Additionally, the bond-slip behavior of the reinforced concrete after suffering the freeze-thaw damage and steel corrosion has also be presented. The results show that the freeze-thaw damage aggravates the steel corrosion in concrete, and the results become more obvious in the concrete after suffering serious freeze-thaw damage. Compared with the ordinary concrete, both air entrained concrete and waterproofing concrete possess better resistance to steel corrosion under the same freeze-thaw environment. Moreover, increasing the thicknesses of concrete cover is also an effective method of improving the resistance to steel corrosion. The bond-slip behavior of reinforced concrete with corroded steel decreases with the increase of freeze-thaw damage, especially for the concrete that suffered high freeze-thaw cycles. Moreover, there exists a good correlation between the parameters of bond-slip and freeze-thaw cycles. The steel corrosion and bond-slip behavior of reinforced concrete should be considered serious under freeze-thaw cycles environment, which significantly impact the durability and safety of concrete structure.

scholarly journals Mechanical Properties of Concrete After Chlorine Salt Extraction in Freeze-Thaw Environment

2014 ◽  
Vol 8 (1) ◽  
pp. 360-367 ◽  
Author(s):  
Liu Faming ◽  
Ye Shujin ◽  
Ma Jie
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Economic Losses ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Electrochemical Chloride Extraction

Steel corrosion caused by chlorine salt erosion, degrade performance of reinforced concrete structures. Lead to can't use or need to reinforce the maintenance structure, produce the huge economic losses. The research of this subject is also a worldwide difficult problem. The freeze-thaw damage of concrete is a complex process of physical change. The chlorine salt erosion is often accompanied by freezing and thawing process. Make concrete structure is in a very bad environment. According to different sources of chloride ion and adopt general international electrochemical chloride extraction testing method of concrete specimens after different freezing and thawing times, the effect of chloride extraction, compressive strength, permeability resistance are studied. It is concluded that the chloride extraction, the strength and durability of the concrete member after freezing and thawing has had certain improvement, especially the durability has a lot to improve. In addition, put forward to increase thickness of concrete cover, preferable high-performance concrete resistance to chloride, strictly control the content of chlorine ion in concrete raw materials, adding reinforcement rust and corrosion inhibitor, adopting concrete corrosion layer, special steel, cathodic protection and so on measures to prevent the chlorine salt erosion. For electrochemical chloride extraction technique in reinforced concrete hydraulic structure, the application of civil engineering in the marine environment which it is provided the theoretical foundation and promotion.

Fracture Analysis of Reinforced Concrete Bridge Structures with Account of Concrete Cracking under Steel Corrosion

2013 ◽  
Vol 831 ◽  
pp. 364-369 ◽  
Author(s):  
Andrey V. Benin ◽  
Artem S. Semenov ◽  
S.G. Semenov
Keyword(s):  
Reinforced Concrete ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Concrete Bridge ◽  
Bond Slip ◽  
Reinforced Concrete Bridge ◽  
Initiation And Propagation ◽  
Bridge Structures ◽  
Concrete Blocks ◽  
Fracture Processes

A direct 3D finite element (FE) modeling of fracture processes in reinforced concrete bridge structures is considered with account of the macrocracks initiation and propagation, real geometry of reinforcing elements, discontinuity in the bond-slip behavior, using elastic-plastic-damage constitutive equations for concrete. The comparison of obtained FE results with experimental data is presented and discussed for the pulling ribbed bars out of concrete blocks, the spalling of concrete cover at the automobile bridge and cracking of ballastless deck at the railway bridge.

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.

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.

Analysis on Concrete Neutralization and Life Evaluation of Reinforced Concrete Chimney

2013 ◽  
Vol 671-674 ◽  
pp. 1672-1675
Author(s):  
Yan Hui Li ◽  
Yang Yang Zhang ◽  
Jing Cun Wei ◽  
Yun Feng Wu
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Structure ◽  
Concrete Cover ◽  
Initiation Time ◽  
Reinforcement Corrosion ◽  
Single Factor ◽  
Routine Examination ◽  
Life Evaluation ◽  
Reinforced Concrete Chimney

Through calculation and analysis on routine examination and neutralization of reinforced concrete chimney, the service life of concrete structure was evaluated only considering neutralization of concrete single factor. The results show that the neutralization of the reinforced concrete chimney was serious than that of other similar projects. The initiation time of reinforcement corrosion were 19.3a, cracking time of concrete cover were 27.35a.

Aging Mechanism of Dam Concrete under the Action of Freeze-Thaw Damage

2014 ◽  
Vol 584-586 ◽  
pp. 2121-2124
Author(s):  
Yan Shi ◽  
Hua Quan Yang ◽  
Xiang Li ◽  
Jia Zheng Li
Keyword(s):  
Weight Loss ◽  
Elastic Modulus ◽  
Concrete Structure ◽  
Loss Rate ◽  
Hydration Products ◽  
Weight Loss Rate ◽  
Freeze Thaw ◽  
Aging Mechanism ◽  
Dam Concrete ◽  
Air Entrained Concrete

Aging mechanism of dam concrete under the action of freeze-thaw damage was analyzed by testing macro and micro performance. The results show that compressive, splitting tensile and flexural strengths reached 58.4%, 61.3% and 57.8% of the initial values after 150 cycles. Strength is the most sensitive indicator of freeze-thaw damage, followed by weight loss rate, relative dynamic elastic modulus and ultrasonic velocity. After freeze-thaw damage, concrete structure becomes loose, porous amount gradually increased and pore size especially over 25nm expanded. Microcracks not only exist in the hydration products, but also destroy the bubbles structure in air entrained concrete, which is the main cause of freeze-thaw damage.

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.

scholarly journals The Investigation of The Different Types of the Ground Rebar Spacers with Proposing New Design Rebar Space Mixed of Concrete Palstic

2020 ◽  
Vol 1 (1) ◽  
pp. 01-06
Author(s):  
Sevar Neamat ◽  
Mahmood Shamsborhan
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Plastic Material ◽  
Vital Role ◽  
Concrete Cover ◽  
Cementitious Material ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Review Study ◽  
Cover Thickness

The reinforcing spacers are commonly prepared from cementitious material, plastic or metals. These spacers are prepared to provide the reinforcing steel with ensuring that the requested concrete cover thickness is attained to guard surrounded steel from corrosion. Also, they pretend a vital role in the concrete structure performance. The toughness of reinforced concrete buildings remains extremely reliant on the features of the protection of concrete to be strong with thickness. A disappointment in finding cover thickness is considered the main impact on early deterioration within the steel, whichever in chance is a chief weaken method in reinforced concrete constructions. The specified study offerings a review study on the investigation of the advantages and disadvantages of six factors in various types concerning the ground rebar spacers studies. As a result, different types of ground rebar spacers have been compared and the new rebar spacer has been designed mixed of concrete_ plastic material

scholarly journals Freeze-Thaw Durability of Air-Entrained Concrete

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Huai-Shuai Shang ◽  
Ting-Hua Yi
Keyword(s):  
Weight Loss ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Test Method ◽  
Internal Crack ◽  
Freeze Thaw ◽  
Ordinary Concrete ◽  
Dynamic Modulus Of Elasticity ◽  
Air Entrained Concrete

One of the most damaging actions affecting concrete is the abrupt temperature change (freeze-thaw cycles). The types of deterioration of concrete structures by cyclic freeze-thaw can be largely classified into surface scaling (characterized by the weight loss) and internal crack growth (characterized by the loss of dynamic modulus of elasticity). The present study explored the durability of concrete made with air-entraining agent subjected to 0, 100, 200, 300, and 400 cycles of freeze-thaw. The experimental study of C20, C25, C30, C40, and C50 air-entrained concrete specimens was completed according to “the test method of long-term and durability on ordinary concrete” GB/T 50082-2009. The dynamic modulus of elasticity and weight loss of specimens were measured after different cycles of freeze-thaw. The influence of freeze-thaw cycles on the relative dynamic modulus of elasticity and weight loss was analyzed. The findings showed that the dynamic modulus of elasticity and weight decreased as the freeze-thaw cycles were repeated. They revealed that the C30, C40, and C50 air-entrained concrete was still durable after 300 cycles of freeze-thaw according to the experimental results.

scholarly journals Parameters That Influence Corrosion Detection in Reinforced Concrete Based on Eddy Current Thermography

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Lu Liu ◽  
Dan Zheng ◽  
Jianting Zhou ◽  
Juan Yang ◽  
Hong Zhang
Keyword(s):  
Reinforced Concrete ◽  
Surface Temperature ◽  
Temperature Change ◽  
Eddy Current ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Quantitative Detection ◽  
Surface Temperature Change ◽  
Temperature Changes ◽  
Steel Bar

This study introduces an eddy current thermography technique that can be used to detect and evaluate steel corrosion in a reinforced concrete structure. The rate of surface temperature changes in reinforced concrete is proposed as a means to characterize the degree of steel bar corrosion. The rate of surface temperature changes increased gradually with an increase in the corrosion degree. The influence of structural parameters on the rate of the temperature change was analyzed in detail. The results indicated that the rate of surface temperature change increased with a decrease in the concrete cover depth and with an increase in the humidity of the concrete, and this was affected by the diameter of the internal steel bar. Concrete cover was the most significant factor that affected the rate of the surface temperature change, except for the corrosion degree. The variations in the surface temperature of reinforced concrete can be explained using the law of electromagnetic induction and the electrochemical property change of corroded steel bar. This research provides a reliable basis for real-world applications and is helpful to understand the application scope of eddy current thermography technology for the quantitative detection of steel corrosion.

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