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.....

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.

scholarly journals A Prediction Model of the Concrete Cracking Induced by the Non-Uniform Corrosion of the Steel Reinforcement

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 830 ◽  
Author(s):  
Wenjun ZHU ◽  
Kequan YU ◽  
Yude XU ◽  
Kai ZHANG ◽  
Xiaopei CAI
Keyword(s):  
Prediction Model ◽  
Concrete Cover ◽  
Corrosion Layer ◽  
Steel Reinforcement ◽  
Corrosion Products ◽  
Uniform Corrosion ◽  
Concrete Cracking ◽  
Volumetric Expansion ◽  
Cracking Performance ◽  
Thick Cylinder

This paper investigates the influence of non-uniform corrosion in the transversal direction of the steel reinforcement on the cracking propagation of the concrete cover. An analytical model is proposed for the prediction of the corrosion-induced cracking performance. Both the thick cylinder theory of the concrete and the effect of transversal non-uniform corrosion of the steel reinforcement are involved by considering the corrosion layer of the corrosion products and a layer of concrete with the corrosion products filled with the pores. A three-stage corrosion-induced cracking of the concrete is proposed: corrosion without expansive stress to the concrete, corrosion with expansive stress to the adjacent concrete, as well as the corrosion-induced cracking of the concrete. By considering the non-uniform corrosion of the steel reinforcement and the tensile stress induced by the volumetric expansion of the corrosion products, the cracking initiation resulting from the non-uniform corrosion was involved in the prediction model. The models were also validated by the experimental results from both the corroded specimens and the existing literature, which would be helpful for the evaluation of the existing reinforced concrete constructions in the marine environment.

Microstructure Analysis of the Rust Developing at Steel-Concrete Interface

2008 ◽  
Vol 400-402 ◽  
pp. 215-220
Author(s):  
Rong Zhen Dong ◽  
Jun Wei ◽  
Xi Wu Zhou
Keyword(s):  
Iron Oxidation ◽  
Concrete Cover ◽  
Forming Process ◽  
Final State ◽  
Steel Bar ◽  
Galvanostatic Method ◽  
Hematite Fe2o3 ◽  
Distribution Composition ◽  
Corrosion Of Steel ◽  
Concrete Interface

The rust distribution and the crack expansion in the deteriorated concrete were studied through the macroscopic and microcosmic method. The results show that the corrosion of steel bar in the concrete is non-uniform even though by Galvanostatic Method. The crack appears earlier and expands quicker at the thin concrete cover than others side and the short crack filled by the rust is found near by the steel bar and converges the main crack. The distribution, composition and the developing of the rust at steel-concrete interface were studied by the microscopic methods of BSE, EDAX and Raman Microscope. By these methods, the rust distributes inhomogeneous and the ion element area was divided into zones evidently. From concrete to steel bar, the rust in turn is: initial rust zone, the mixture area of the rust and mortar about 20-50 μm in width and main containing the goethite (FeOOH); the secondary rust zone, high density area of ion element and about 10-20μm in width and being the mixture of hematite（Fe2O3）and magnetite(Fe3O4); the final rust zone, similar as the initial rust and being the mixture of hematite(Fe2O3)and goethite(FeOOH). According to the electrochemistry principle, the forming process of rust does not follow the iron oxidation procedure entirely but form middle production under the special situation of the condition interior concrete and the electric field outside. The extrusion action of concrete around steel bar makes the rust compressed and metamorphic and the secondary rust forming. So the process and the final state of this special corrosion production are the key parameters leading to the deterioration of concrete.

scholarly journals In Vitro Degradation of Absorbable Zinc Alloys in Artificial Urine

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 295 ◽  
Author(s):  
Sébastien Champagne ◽  
Ehsan Mostaed ◽  
Fariba Safizadeh ◽  
Edward Ghali ◽  
Maurizio Vedani ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Urinary Tract Obstruction ◽  
Calcium Content ◽  
Corrosion Layer ◽  
Uniform Corrosion ◽  
In Vitro Degradation ◽  
Pure Zinc ◽  
Zinc Alloys ◽  
Artificial Urine

Absorbable metals have potential for making in-demand rigid temporary stents for the treatment of urinary tract obstruction, where polymers have reached their limits. In this work, in vitro degradation behavior of absorbable zinc alloys in artificial urine was studied using electrochemical methods and advanced surface characterization techniques with a comparison to a magnesium alloy. The results showed that pure zinc and its alloys (Zn–0.5Mg, Zn–1Mg, Zn–0.5Al) exhibited slower corrosion than pure magnesium and an Mg–2Zn–1Mn alloy. The corrosion layer was composed mostly of hydroxide, carbonate, and phosphate, without calcium content for the zinc group. Among all tested metals, the Zn–0.5Al alloy exhibited a uniform corrosion layer with low affinity with the ions in artificial urine.

scholarly journals Relationship model between surface strain of concrete and expansion force of reinforcement rust

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fanxiu Chen ◽  
Zuquan Jin ◽  
Endong Wang ◽  
Lanqin Wang ◽  
Yudan Jiang ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Real Time ◽  
Steel Corrosion ◽  
Surface Strain ◽  
Concrete Cracking ◽  
Whole Process ◽  
Steel Bars ◽  
Relationship Model ◽  
Expansion Force ◽  
Corrosion Of Steel

AbstractConcrete cracking caused by corrosion of reinforcement could significantly shorten the durability of reinforced concrete structure. It remains critical to investigate the process and mechanism of the corrosion occurring to concrete reinforcement and establish the theoretical prediction model of concrete expansion force for the whole process of corrosion cracking of reinforcement. Under the premise of uniform corrosion of reinforcing steel bars, the elastic mechanics analysis method is adopted to analyze the entire process starting from the corrosion of steel bars to the cracking of concrete due to corrosion. A relationship model between the expansion force of corrosion of steel bars and the surface strain of concrete is established. On the cuboid reinforced concrete specimens with square cross-sections, accelerated corrosion tests are carried out to calibrate and verify the established model. The model can be able to estimate the real-time expansion force of reinforced concrete at any time of the whole process from the initiation of steel corrosion to the end of concrete cracking by measuring the surface strain of concrete. It could be useful for quantitative real-time monitoring of steel corrosion in concrete structures.

Experiment Study on Degradation Laws of Sulfuric Acid Corrosion Reinforcements

2018 ◽  
Vol 878 ◽  
pp. 23-27 ◽  
Author(s):  
Ming Qiang Lin ◽  
Feng Juan Dai ◽  
Jia Tao Li
Keyword(s):  
Sulfuric Acid ◽  
Acid Corrosion ◽  
Constitutive Models ◽  
Corrosion Damage ◽  
Uniform Corrosion ◽  
Steel Bars ◽  
Relationship Model ◽  
Strain Relationship ◽  
Sulfuric Acid Corrosion ◽  
Corrosion Of Steel

The corrosion of concrete structures is serious in sulfuric acid environments. Corrosion damage of reinforcements caused sulfuric acid corrosion is very serious. The rapid experiments of sulfuric acid corrosion steel bars were carried out, and the apparent morphology and mechanical properties of sulfuric acid corrosion steel bars were studied. The results show that the corrosion of steel bars is uniform corrosion. With the increase of corrosion rate, the yield platforms and the yield strengths and ultimate strengths are reduced. Based on the experimental datas, the relationship models between yield strengths and ultimate strengths and corrosion rates were obtained. The constitutive models of corrosion steel bars were established. The stress - strain relationship model is in good agreement with the experimental data.

scholarly journals Corrosion of steel in concrete due to one and two dimensional chloride ingress

2018 ◽  
Vol 199 ◽  
pp. 04004
Author(s):  
Ze Gyang Zakka ◽  
Mike Otieno
Keyword(s):  
Corrosion Rate ◽  
Concrete Beams ◽  
Concrete Cover ◽  
Steel Reinforcement ◽  
Chloride Ingress ◽  
Single Crack ◽  
Ongoing Research ◽  
Concrete Resistivity ◽  
Corrosion Of Steel ◽  
Cracked Specimens

This paper presents results of an ongoing research of the effect of 1D and 2D chloride ingress on concrete resistivity and corrosion rate of steel reinforcement. 12 concrete beams made with concrete of binder blend PC(50)/GGBS(50), w/b = 0.40, 10 mm steel reinforcement rods at concrete cover of 20 mm were used in this laboratory based experiment. The steel reinforcement bars were placed at the middle or at an orthogonal corner of the concrete beams subjected to 1D and 2D chloride ingress respectively. A single crack was induced using 3-point bending on one-half of the beams. The beams were exposed to a repeated cycle of 2 weeks ponding in 5% NaCl and then air drying in ambient laboratory condition for 2 weeks. The corrosion rate of both cracked and uncracked specimens exposed to 2D chloride ingress was significantly higher than that of beams exposed to 1D chloride ingress. The uncracked specimens had lower concrete resistivity values compared to the cracked specimens even though higher corrosion rates were measured.

Determination of Cl- in Concrete Materials by Ion Chromatography

2016 ◽  
Vol 680 ◽  
pp. 52-55
Author(s):  
Hong Yan Guan ◽  
Jian Jun Ding ◽  
Zhong Bao Guo ◽  
Ming Yu Wang ◽  
Yi Fei Mei
Keyword(s):  
Detection Limit ◽  
Ion Chromatography ◽  
Potential Method ◽  
Concrete Cover ◽  
Chloride Ions ◽  
Accurate Analysis ◽  
Chromatography Method ◽  
Concrete Materials ◽  
Corrosion Of Steel

The determination of chloride ions in concrete materials accurately is far and away crucial, since chloride ions can cause corrosion of steel and concrete cover off. The conventional potential method and silver nitrate titration method usually show features of simple operation and short duration, nevertheless, they are not suitable for accurate analysis for concrete attributing to their low accuracy and detection limit. In this paper, an ion chromatography method was presented to determine chlorine in concrete materials. Concrete samples were pre-processed and then extracted with distilled water. The extraction solutions were purified on a 0.22 μm filter membrane, an On Guard SPE-RP column and a SPE-H column sequentially for eliminating undissolved substance, organisms and metal ions before ion chromatographic analysis. The chromatographic separation was performed on a Dionex ICS-1000 Chromatographic using 25.0 mmol/L KOH solutions as mobile phase at 1.0 mL/min. Results show that the detection limit of the method was 0.004 mg/L. The linear relationship of the external Cl- standard solutions was 0.9994, and the sample analytical RSD was 0.44%.

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