scholarly journals Concrete Protective Layer Cracking Caused by Non-Uniform Corrosion of Reinforcements

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4245 ◽  
Author(s):  
Lu Zhang ◽  
Ditao Niu ◽  
Bo Wen ◽  
Daming Luo
Keyword(s):  
Radial Displacement ◽  
Concrete Strength ◽  
Protective Layer ◽  
Concrete Cover ◽  
Uniform Corrosion ◽  
Reinforcement Corrosion ◽  
Concrete Cracking ◽  
Principal Tensile Stress ◽  
Cover Thickness ◽  
Corrosion Of Steel

The volume expansion of reinforcement corrosion products resulting from the corrosion of steel reinforcement embedded into concrete causes the concrete’s protective layer to crack or spall, reducing the durability of the concrete structure. Thus, it is necessary to analyze concrete cracking caused by reinforcement corrosion. This study focused on the occurrence of non-uniform reinforcement corrosion in a natural environment. The characteristics of the rust layer were used to deduce the unequal radial displacement distribution function of concrete around both angular and non-angular bars. Additionally, the relationship between the corrosion ratio and the radial displacement of the concrete around the bar was established quantitatively. Concrete cracking due to the non-uniform corrosion of reinforcements was simulated using steel bars embedded in concrete that were of uneven displacement because of rust expansion. The distribution of the principal tensile stress around the bar was examined. A formula for calculating the critical radial displacement at the point when cracking began was obtained and used to predict the corrosion ratio of the concrete cover. The determined analytical corrosion ratio agreed well with the test result. The effect factor analysis based on the finite element method indicated that increasing the concrete strength and concrete cover thickness delays concrete cracking and that the adjacent rebar causes the stress superposition phenomenon.

Study on Concrete Cracking Caused by Non-Uniform Corrosion of Steel Bar

2021 ◽  
Author(s):  
Huaishuai Shang ◽  
Jirui Liu
Keyword(s):  
Elastic Plate ◽  
Concrete Cover ◽  
Corrosion Layer ◽  
Uniform Corrosion ◽  
Concrete Cracking ◽  
Corrosion Depth ◽  
Steel Bar ◽  
Corrosion Of Steel ◽  
Elastic Mechanics ◽  
Period Model

In this paper, the cracking of concrete cover caused by steel bar corrosion was discussed and studied based on the three-period model of steel bar corrosion in concrete. In the analysis, according to the non-uniformity of steel bar in reinforced concrete under natural environment, the contour of corrosion layer is simplified into a semi-ellipse. The steel bar corrosion was divided into three different periods by two corrosion points, namely, the void to be filled was exactly filled and the concrete cover was exactly cracked. Different model assumptions are made for each corrosion period. Before the concrete cover cracks, it is developed into an elastic plate. Based on the theory of elastic mechanics, the maximum corrosion depth of steel bar when concrete cover cracks is predicted.....

Experimental Research on Factors Affecting Factors of Concrete Strength in Corrosion and Expanding Areas at Initial Stages of Reinforcement

2014 ◽  
Vol 1065-1069 ◽  
pp. 1174-1180
Author(s):  
Xi De Zhang ◽  
Zhen Zhou ◽  
Guo Zhu Li
Keyword(s):  
Experimental Research ◽  
Concrete Strength ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Reinforcement Corrosion ◽  
Affecting Factors ◽  
Factors Affecting

This studypaper analyzed the affecting factors affecting of strength of concrete in corrosion and expanding areas at initial stages of reinforcement corrosion by experimental resultss, and researched the transformation trend of experimental factors by difference analyzing in statistics. The results showed that the expanding force after steel corrosion remarkably influenceds the strength of concrete. At the same time, the reinforcement diameter and thickness of concrete cover also had clear influence on concrete strength when rust occurroccurrenceed. Therefore, when studying the influence of corrosion and expanding force on concrete strength, we should not only research the influence of reinforcement corrosion magnitude, but also consider other effects, such as steel diameter, thickness of concrete cover should be considered.

Experimental Study on Post-Anchoring Pulling-Out Bearing Capacity of Inorganic Materials in Concrete Test Cubes

2012 ◽  
Vol 166-169 ◽  
pp. 420-425
Author(s):  
Shi Qi Cui ◽  
Li Ping Jiang ◽  
Bo Cheng ◽  
Tao Wang
Keyword(s):  
Experimental Study ◽  
Theoretical Basis ◽  
Inorganic Material ◽  
Concrete Strength ◽  
Technical Specification ◽  
Concrete Cover ◽  
Adhesive Property ◽  
Inorganic Materials ◽  
Transverse Reinforcement ◽  
Cover Thickness

Through the test and observe the failure deformation in concrete test cube, the paper analyze the influence of concrete strength, concrete cover thickness, internal reinforcement cage(transverse reinforcement), reinforcement diameter on the inorganic material reinforcement adhesive property, providing theoretical basis for the code of Technical specification for post-anchoring used in concrete structure with inorganic anchoring material.

scholarly journals Modeling of Cover Concrete Cracking Due to Uniform Corrosion of Reinforcement

2021 ◽  
Vol 12 (1) ◽  
pp. 43-49
Author(s):  
Sheikh Shakib ◽  
Abu Zakir Morshed
Keyword(s):  
Tensile Strength ◽  
Concrete Cover ◽  
Uniform Corrosion ◽  
Crack Initiation And Propagation ◽  
Rc Structures ◽  
Material Parameters ◽  
Cover Concrete ◽  
Initiation And Propagation ◽  
Cover Thickness ◽  
Bar Diameter

Cracking of cover concrete due to the corrosion of reinforcing steel is one of the main causes of deterioration in Reinforced Concrete (RC) structures. An outbound stress is developed in concrete surrounding the reinforcing steels due to the expansive corrosion products of reinforcement leading to cracking of the concrete cover. In this paper, the cracking pressure was simulated through a finite element modeling. The effect of geometrical and material parameters, i.e. concrete cover thickness, bar diameter, and concrete tensile strength, on the cracking pressure was also investigated. Abaqus 6.14 was used as modeling platform. The cracking pressure was found to dependent on the cover thickness and tensile strength of concrete. A higher pressure was required to initiate crack for a higher cover thicknesses and tensile strength. The cracking pressure was decreased with the increase in bar diameter. Finally the crack initiation and propagation has been simulated successfully for different arrangements of reinforcements. Journal of Engineering Science 12(1), 2021, 43-49

MODELING THE PROCESS OF INSPECTION OF REINFORCED CONCRETE SUPPORTS OF TECHNOLOGICAL OVERPASSES

2021 ◽  
Vol 14 (1) ◽  
pp. 68-73
Author(s):  
N Rogov ◽  
S. Nikolenko ◽  
Svetlana Sazonova
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Technical Condition ◽  
Concrete Cover ◽  
Magnetic Method ◽  
Strength Of Materials ◽  
Elastic Rebound ◽  
Cover Thickness ◽  
Non Destructive

The paper presents the process of assessing the technical condition of reinforced concrete supports of existing technological overpasses. The characteristics of overpasses are given. Defects identified in the process of assessing the technical condition are shown. The paper describes the control of concrete strength by the non-destructive method of elastic rebound using the Digi Shmidt 2000 device and the determination of the concrete cover thickness and the location of reinforcement by the magnetic method using the Profometer-5S device. The layout of the working reinforcement in the reinforced concrete supports of the overpass section has been determined. The results of verification calculations of the structures of technological ramps are given, taking into account the revealed defects and damages, the strength of materials and the specified actual loads. Proposals are given for improving the performance of concrete of reinforced concrete supports of overpasses.

Experimental Study on Bond-Slip between Steel Bar and Recycled Aggregate Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 1651-1656 ◽  
Author(s):  
Qing Feng Huang ◽  
Da Fu Wang
Keyword(s):  
Concrete Strength ◽  
Concrete Cover ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Bond Slip ◽  
Pull Out ◽  
Steel Bar ◽  
Cover Thickness

By a static and repeated pull-out experiment between steel bar and recycled aggregate concrete, and bond-slip curves between recycled concrete with different recycled coarse aggregate(RCA) replacement percentages were recorded. Based on the analysis of the experimental results, replacement percentages of recycled concrete, cover thickness, anchorage length, concrete strength and loading method was investigated. At last, the bond-slip constitutive relation was also discussed.

The Analysis of the Reliability and Design for Mechanical Anchorage of HRB500 Steel Bars

2011 ◽  
Vol 94-96 ◽  
pp. 970-974
Author(s):  
Xian Rong ◽  
Peng Cheng Liu ◽  
Xue Li
Keyword(s):  
Concrete Strength ◽  
Concrete Cover ◽  
Statistical Regression ◽  
Analysis Method ◽  
Anchorage Length ◽  
Pull Out ◽  
Steel Bar ◽  
Steel Bars ◽  
Mechanical Anchoring ◽  
Cover Thickness

The factors on mechanical anchoring performance of HRB500 steel bars, such as concrete strength, concrete cover thickness, diameter of steel bar, anchorage length of steel bar and transverse reinforcement ratio, were studied based on pull-out tests of 45 specimens. And the formula of mechanical anchoring bond strength for HRB500 steel bars was concluded by statistical regression analysis method. Through the reliability analysis, the mechanical anchoring length of design value and the table of conversion ratio between mechanical and direct anchoring length of HRB500 steel bars have been proposed. So it could be used as a basis for practical projects. The results indicate that the mechanical anchorage length of HRB500 steel bars can be still designed with the formula proposed in GB 50010-2002 “Code for design of concrete structures”.

Pitting Corrosion Propagation Analysis of Reinforcement in RC Bridge Beams Considering Uncertain Information

2012 ◽  
Vol 204-208 ◽  
pp. 3174-3181
Author(s):  
Ya Fei Ma ◽  
Jian Ren Zhang ◽  
Lei Wang
Keyword(s):  
Pitting Corrosion ◽  
Concrete Strength ◽  
Concrete Cover ◽  
Concrete Bridge ◽  
Uncertain Information ◽  
Distribution Parameters ◽  
Evolutionary Characteristic ◽  
Pit Depth ◽  
Cover Thickness ◽  
Two Stages

The prediction of pitting corrosion-induced structural performance degradation is limited by the inspection means and experimental data. Incomplete information and tempral and spatial uncertainties of corrosion are integrated to develop the time-dependent pit depth model. The reinforcement corrosion is divided into two stages in this model. The approach is illustrated by a removed concrete bridge. The evolutionary characteristic of probability density function of the pit depth is analyzed, and the probabilistic distribution pattern and distribution parameters are also obtained. Besides, The sensitivity of input parameters on the pitting model are also discussed. The results show that under appropriate conditions of concrete strength (>25MPa), increase the same percentage of concrete strength is more sensitive to the pit depth than improvement the same percentage of concrete cover thickness. The effects of continuous improvement of concrete strength or increase the thickness on corrosion depth gradually decreases. The proposed procedure can be used to evaluation of existing reinforced concrete bridge.

Reinforcement Corrosion and its Effect on Bond Behaviour

2016 ◽  
Vol 837 ◽  
pp. 179-182
Author(s):  
Ivan Holly ◽  
Katarina Gajdosova ◽  
Robert Sonnenschein
Keyword(s):  
Concrete Cover ◽  
Internal Stresses ◽  
Reinforced Concrete Structures ◽  
Reinforcement Corrosion ◽  
Cross Sectional ◽  
Bond Behaviour ◽  
Concrete Corrosion ◽  
Corrosion Of Steel ◽  
The Relationship ◽  
Crack Widths

The corrosion of reinforcement is one of the predominant reasons for loss of reliability of reinforced concrete structures. This has an impact on safety, serviceability and durability of the structure. The corrosion of steel in concrete reduces the cross sectional area of the reinforcement and decreases the bond between reinforcement and concrete. Corrosion products have a higher volume than steel, which produces internal stresses that lead to the cracking and spalling of the concrete cover. Additionally, corrosion of steel changes the mechanical properties of reinforcement. In this paper, the relationship between crack widths and bond strength between reinforcement and concrete was investigated.

scholarly journals Manufacturing Errors of Concrete Cover as a Reason of Reinforcement Corrosion in a Precast Element—Case Study

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 702 ◽  
Author(s):  
Kamil Bacharz ◽  
Wioletta Raczkiewicz ◽  
Magdalena Bacharz ◽  
Wioletta Grzmil
Keyword(s):  
Protective Coatings ◽  
Pulse Method ◽  
Technical Condition ◽  
Concrete Cover ◽  
Reinforcement Corrosion ◽  
Manufacturing Errors ◽  
Precast Elements ◽  
Cover Thickness ◽  
Reinforcement Distribution ◽  
Non Destructive

The article concerns the assessment of technical condition of the precast loggia wall in a large panel building after 25 years of use as well as the cause of its damage. As a result of the study, cracks and losses of the concrete cover were found. Corrosion products were visible on exposed reinforcing rods. The reinforcement distribution and concrete cover thickness in loggia wall were estimated using a rebar detector. The corrosion assessment of reinforcement was performed using a semi non-destructive galvanostatic pulse method that allows the location of areas of corrosion and estimate the reinforcement corrosion activity. The phase composition of the concrete cover was analyzed. The test results showed an insufficient thickness of the concrete cover as the main cause of loggia wall damage. The research indicated that manufacturing errors made in the prefabrication plants affect the technical condition of precast elements and may lead to the damage of the structure well before the expected of its service life. In the case of manufacturing errors causing the implementation of an element with a concrete cover that does not meet the standard requirements for thickness and tightness, it is recommended to use protective coatings to increase the element’s durability to the designed level.

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