Corrosion of Reinforced Concrete in Accelerated Tests

2012 ◽  
Vol 610-613 ◽  
pp. 485-489
Author(s):  
Wan You Zhang ◽  
Rui Yuan Zhang ◽  
Lijuan Xi
Keyword(s):  
Reinforced Concrete ◽  
Surface Morphology ◽  
Steel Corrosion ◽  
Potential Change ◽  
Accelerated Tests ◽  
Accelerated Corrosion ◽  
Faraday’S Law ◽  
Full Immersion ◽  
Natural Corrosion

In order to study the correlation between accelerated corrosion and natural corrosion, reinforced surface morphology, steel potentials and corrosion quality were investigated by using full immersion and half immersion in this paper. The results showed that the effort of half immersion accelerated corrosion was similar to natural corrosion, and each of the tendencies of potential change was same, but the mechanisms of corrosion were different. The degree of steel corrosion, estimated by Faraday’s law, was slightly higher than the level of actual corrosion.

On Comparison between Reinforcement Electricity Accelerated Corrosion and Natural Corrosion of Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 676-679 ◽  
Author(s):  
Sen Li ◽  
Jun Yin Yan ◽  
Xiao Gang Wang
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Experimental Research ◽  
Comparative Research ◽  
Corrosion Process ◽  
Common Method ◽  
Corrosion Mechanism ◽  
Accelerated Corrosion ◽  
Electric Flux ◽  
Natural Corrosion

Electricity accelerated corrosion is a common method to obtain corroded reinforced concrete specimens in current experimental research, and it has some relevance and differences with natural corrosion. The paper undertakes a detailed comparative research on the relevance and differences of the two corrosion conditions from the corrosion mechanism, the corrosion process, the corrosion rate, the electric flux and corrosion features, and this provide a better understanding of the research achievements based on accelerated corrosion.

scholarly journals Time Scale of Chloride-Induced Corrosion on Circular Section RC Linked Accelerated Test to Natural Corrosion

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yue Zhang ◽  
Fangyan Lan ◽  
Mi Zhou ◽  
Ke Wang
Keyword(s):  
Time Scale ◽  
Time Correlation ◽  
Corrosion Process ◽  
Accelerated Corrosion ◽  
Circular Section ◽  
Rc Structures ◽  
Chloride Corrosion ◽  
Faraday’S Law ◽  
Chloride Environment ◽  
Natural Corrosion

The time scale in accelerated decay is essential for studying the durability of reinforced concrete (RC) structures exposed to the chloride corrosion environment. An accelerated corrosion test (ACT) was carried out on RC specimens were conducted under different chloride concentrations and applied voltages, with the information of steel measured. A novel prediction model of the complete corrosion process is proposed to evaluate the time correlation between accelerated decay and natural corrosion. The corrosion process of RC is divided into two stages: corrosion initial stage and corrosion stage of reinforcement. For the first stage, the coefficient of circular section members is presented. For the second stage, the accelerated factor of the test for the natural environment is proposed based on the Arrhenius-type and Faraday’s law. It is calculated by making regressions among some values of parameters, while moving to natural corrosion are extrapolating. The accelerating effect of applied voltages increases in the low-chloride environment, which is better than that in the high-chloride environment. This study provides calibration of the time scale for laboratory tests to analyze the performance of RC structures after corrosion.

scholarly journals Assessment of corrosion-induced bond deterioration in reinforced concrete: towards a splitting crack-based approach

2021 ◽  
Author(s):  
Michele Win Tai Mak ◽  
Janet M. Lees
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Steel Corrosion ◽  
Concrete Bridges ◽  
Reinforcing Bars ◽  
Accelerated Corrosion ◽  
General Validity ◽  
Safety Risks ◽  
Infrastructure Network ◽  
Residual Capacity

<p>Reinforced concrete structures are subjected to several sources of deterioration that can reduce their load-resisting capacity over time. This has significant consequences for the management of infrastructure, leading to high costs of maintenance, repair, strengthening and premature decommissioning. Assessing the residual capacity of structures is challenging but paramount to manage the infrastructure network effectively. Corrosion of the internal steel reinforcement is among the main causes of deterioration in reinforced concrete bridges. The subsequent reduction in steel-to-concrete bond strength is difficult to evaluate with accuracy. There is no unified theory of general validity. Most existing models adopt measures of the level of corrosion as the key parameter to evaluate the bond reduction. In this paper, a different approach is investigated. Corrosion-induced splitting crack widths are used as the fundamental indicator of bond strength reduction, irrespective of the associated degree of steel corrosion. Available experimental results on deformed steel bars embedded in concrete subjected to either natural or accelerated corrosion, with or without transverse reinforcement, are analysed and compared with a different perspective. The analysis indicates that this new splitting crack-based approach can lead to more accurate predictions. This contributes to a better understanding of the fundamental principles underlying bond of corroded reinforcing bars. Enhanced assessment strategies can lead to a reduction of the safety risks, maintenance costs and environmental footprint of the infrastructure network.</p>

scholarly journals Experimental Comparability Among Different Accelerated Reinforced Steel Concrete Corrosion Methods

2018 ◽  
Vol 7 (4.20) ◽  
pp. 209
Author(s):  
Mushtaq Sadiq Radhi ◽  
Maan S. Hassan ◽  
Iqbal N. Gorgis
Keyword(s):  
Reinforced Concrete ◽  
Steel Corrosion ◽  
Corrosion Current ◽  
Steel Reinforcement ◽  
Small Scale ◽  
Accelerated Corrosion ◽  
Galvanostatic Method ◽  
Reinforced Steel ◽  
Impressed Current ◽  
Corrosion Of Steel

The objective of this paper is to inspect the effect of changing the density of the impressed current and wetting-drying condition on accelerated corrosion of reinforced concrete specimens by a galvanostatic method.  Small-scale reinforced concrete columns were prepared and then artificially corroded by different setups of accelerated corrosion under an impressed current and also under different wetting-drying cycles for comparison. The density of the impressed current ranged between 50 and 500 µA/cm2 with different wetting-drying cycles periods. Corrosion current, and cracking were monitored throughout the accelerated corrosion period to determine the level of damage caused by the development of expansive reinforcement steel corrosion products, appearance of the first crack, and pattern of cracking.The results indicated that the galvanostatic method with wetting-drying sequences can be utilized effectively to simulate the normal corrosion of steel reinforcement in the concrete structure. The usage of different intensities of the current has no influence on the crack pattern. Though, increasing the current level leads to a substantial increase in the crack width due to corrosion of the steel reinforcement in a shorter time.  

scholarly journals Propuesta de un nuevo indicador para definir la ductilidad aplicada a la corrosión del acero de refuerzo en estructuras de hormigón = Proposal of a new indicator to define ductility applied to corroded steel reinforcement on concrete structures

2015 ◽  
Vol 1 (2) ◽  
pp. 42
Author(s):  
E. Moreno ◽  
M. I. Prieto ◽  
M. N. González ◽  
N. Llauradó
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Steel Reinforcement ◽  
Single Parameter ◽  
Reinforced Concrete Structures ◽  
Reinforcement Corrosion ◽  
Accelerated Corrosion ◽  
Steel Bars ◽  
Reinforcing Steel Corrosion

ResumenLa carbonatación del hormigón o la intrusión de cloruros en suficiente cantidad para alcanzar el nivel de las barras, es desencadenante de la corrosión de la armadura. Uno de los efectos más significativos de la corrosión del acero de refuerzo en estructuras de hormigón armado es la disminución de las propiedades relacionadas con la ductilidad del acero. El reforzamiento tiene un efecto decisivo en la ductilidad global de las estructuras de hormigón armado. Se utilizan diferentes códigos para clasificar el tipo de acero en función de su ductilidad usando los valores mínimos de varios parámetros. El uso de indicadores de ductilidad asociados a diferentes propiedades puede ser ventajoso en muchas ocasiones. Se considera necesario para definir la ductilidad por medio de un solo parámetro que tiene en cuenta los valores de resistencia y deformación simultáneamente. Hay una serie de criterios para definir la ductilidad del acero mediante un único parámetro. El presente estudio experimental se ocupa de la variación en la ductilidad de las barras de acero embebido en hormigón cuando se expone a la corrosión acelerada. Este trabajo analiza la idoneidad de un nuevo indicador de la ductilidad utilizado en barras corroídas. AbstractThe carbonation of concrete or the chlorides ingress in such quantity to reach the level of bars is triggers of reinforcement corrosion. One of the most significant effects of reinforcing steel corrosion on reinforced concrete structures is the decline in the ductility-related properties of the steel. Reinforcement ductility has a decisive effect on the overall ductility of reinforced concrete structures. Different Codes classify the type of steel depending on their ductility defined by the minimum values of several parameters. Using indicators of ductility associating different properties can be advantageous on many occasions. It is considered necessary to define the ductility by means of a single parameter that considers strength values and deformation simultaneously. There are a number of criteria for defining steel ductility by a single parameter. The present experimental study addresses the variation in the ductility of concrete-embedded steel bars when exposed to accelerated corrosion. This paper analyzes the suitability of a new indicator of ductility used in corroded bars.

scholarly journals Correlation between surface crack width and steel corrosion in reinforced concrete

2018 ◽  
Vol 199 ◽  
pp. 04009 ◽  
Author(s):  
Michele Win Tai Mak ◽  
Pieter Desnerck ◽  
Janet M. Lees
Keyword(s):  
Reinforced Concrete ◽  
Asset Management ◽  
Surface Crack ◽  
Management Strategies ◽  
Steel Corrosion ◽  
Accelerated Corrosion ◽  
Testing Procedures ◽  
Pull Out ◽  
Structural Deterioration ◽  
Impressed Current

Reinforced concrete structures are subjected to weather conditions, chemical attack and other sources of deterioration that can affect their performance. In particular, corrosion of the internal steel reinforcement is considered to be one of the main causes of structural deterioration. A possible consequence of corrosion is cracking of the surrounding concrete. Visual inspections are often used to inform asset management strategies. Finding a relationship between cracks that are visible on the outer surface of a structure and corrosion of the internal reinforcement can be helpful when making assessment decisions. To this end, unconfined cylindrical concrete specimens with an embedded steel bar have been subjected to accelerated corrosion using an impressed current density of 200µA/cm2, leading to steel mass losses between 5-24%. This paper discusses the measured correlation between corrosion-induced surface crack widths and degree of reinforcement corrosion. The tests highlighted some limitations of a set-up that is commonly adopted for accelerated corrosion and concentric pull-out bond testing. The findings of this study represent a first step towards the standardisation of accelerated corrosion testing procedures using an impressed current.

scholarly journals Effect of corrosion degree on different steel ductility parameters, based on “Equivalent Steel” criterion

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Esther Moreno ◽  
Alfonso Cobo ◽  
Maria Nieves Gonzalez
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Design Methodology ◽  
Linear Models ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Reinforced Concrete Structures ◽  
Accelerated Corrosion ◽  
Rc Structures ◽  
Standing Structure

Purpose One of the meaningful effects of concrete reinforcement steel corrosion on concrete structures is the decrease of mechanical properties, specifically the ductility of steel. The term ductility of steel refers to a group of properties which determine the reinforced concrete structures and it is necessary to take this property into account for the recalculation of structures that have been already corroded until the point to condition in many occasions the analysis methodology. Design/methodology/approach This research studies the variation on ductility of concrete embedded steels bars after going through an accelerated corrosion process. Tensile strength of high ductility reinforcements with different corrosion levels has been tested. Ductility was studied in terms of ultimate tensile strength, yield strength, ultimate strain, energy density of deformation and “equivalent steel” criterion. It also makes some considerations about what is the best methodology of structural analysis according to the obtained results. Findings Based on the obtained results, conclusions are established that determine whether the corroded steel satisfy the requirements of different codes in order to identify them as “steels with special characteristics of ductility” assessing in each case the possibility of reallocating solicitations in structures which might need to be repaired. Originality/value The analysis of existing RC structures should address moment redistribution to be able to compare ultimate strength values, rather than to a single value obtained with elastic linear models to a range of values centred on the elastic and linear values obtained and defining an interval equal to double the value of the maximum redistribution capacity. This greatly enhances the possibility of “saving” a standing structure. In ductile structures the effect of actions can be distributed. The ascertainment of corroded reinforcement ductility variation is of key importance in structural re‐engineering and recalculation of structures. The research developed in this article is motivated by the need to contribute to knowledge of the behavior of reinforced concrete structures with reinforcement damaged.

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.

Polypropylene Fibre Reinforced Concrete Air Permeability

1990 ◽  
Vol 211 ◽  
Author(s):  
Miguel A. Sanjuan ◽  
A. Moragues ◽  
B. Bacle ◽  
C. Andrade
Keyword(s):  
Carbon Dioxide ◽  
Reinforced Concrete ◽  
Steel Corrosion ◽  
Air Permeability ◽  
Polypropylene Fibre ◽  
Fibre Reinforced Concrete ◽  
Polypropylene Fibres ◽  
Cement Ratio ◽  
Reinforcing Steel Corrosion

AbstractThe permeability of concrete to gases is of direct importance to the durability of concrete structures, because of carbon dioxide flowing through the concrete favour lime carbonation and reinforcing steel corrosion.Mortar with and without polypropylene fibres having water/cementitious ratios of 0.30, 0.35 and 0.40 and a cement/sand ratio of 1/1 were studied. Polypropylene dosage varied from 0.1 to 0.3% by volume of cement.The characterization of mortar permeability was made using cylindrical shaped samples (3 cm height and 15 cm diameter). These specimens were 28 days cured and then dried before the test.The addition of fibres results in a decrease of air permeability. Variation of the water/cement ratio is of lesser importance than fiber addition.

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