Corrosion of Reinforcing Steel In Concrete in Marine Atmospheres★

CORROSION ◽  
1959 ◽  
Vol 15 (7) ◽  
pp. 60-66 ◽  
Author(s):  
D. A. LEWIS ◽  
W. J. COPENHAGEN
Keyword(s):  
Reinforced Concrete ◽  
Protective Coatings ◽  
Salt Spray ◽  
Concrete Cover ◽  
Reinforcing Steel ◽  
Reinforced Concrete Structure ◽  
Accelerated Corrosion ◽  
Chemical Mechanisms ◽  
Accelerated Corrosion Tests ◽  
Short Time

Abstract Where a reinforced concrete structure is exposed to a marine atmosphere, serious corrosion of the reinforcing steel sometimes takes place within a relatively short time and the concrete cover round the reinforcing is spalled off. This phenomenon, examples of which are described, constitutes a major problem in South Africa, particularly in coastal areas. No exhaustive work on this particular subject is described in the literature and because of the nature of concrete, conventional methods of corrosion prevention find little direct application. The reaction proceeds by electro-chemical mechanisms whose emf's derive from differences in pH, aeration or other factors but whose severity is influenced mainly by presence of sodium chloride in the concrete. Accelerated corrosion tests in a salt spray cabinet using steel reinforced mortar specimens indicated that factors of considerable significance are cover to the steel, protective coatings to the mortar, and the curing, cement content and water cement ratio of the mortar. The effects of these variables in the corrosion of the steel are discussed. A comprehensive series of both accelerated and natural exposures of reinforced concrete specimens in progress is outlined. 6.6.5

scholarly journals Concrete Corrosion Cracking and Transverse Bar Strain Behavior in a Reinforced Concrete Column under Simulated Marine Conditions

2020 ◽  
Vol 10 (5) ◽  
pp. 1794 ◽  
Author(s):  
Gyeongcheol Choe ◽  
Yasuji Shinohara ◽  
Gyuyong Kim ◽  
Sangkyu Lee ◽  
Euibae Lee ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Cover ◽  
Corrosion Cracking ◽  
Reinforced Concrete Column ◽  
Accelerated Corrosion ◽  
Corrosion Tests ◽  
Strain Behavior ◽  
Accelerated Corrosion Tests ◽  
In Situ Conditions ◽  
Rebar Corrosion

This study performed accelerated corrosion tests on reinforced concrete (RC) specimens reinforced with transverse steel bars to evaluate the concrete cracking and rebar strain behaviors caused by rebar corrosion. Seven RC specimens were created with variable compressive strengths, rebar diameters, and concrete cover thicknesses. To mimic in-situ conditions, the accelerated corrosion tests applied a current to the longitudinal bar and transverse bar for different periods of time to create an unbalanced chloride ion distribution. These tests evaluated the amount of rebar corrosion, corrosion cracking properties, and transverse bar strain behavior. The corrosion rate of the transverse bar was faster than that of the longitudinal bar, and cracking first occurred in the concreate around the transverse bar in the specimens with low concrete compressive strength and thin concrete cover. Corrosion cracking and rebar strain were greatly affected by the behavior of the corrosion products that resulted from the pore volume and cracking properties of the cement paste.

Estimation of Corrosion Damage in Steel Reinforced Mortar Using Guided Waves

2005 ◽  
Vol 127 (3) ◽  
pp. 255-261 ◽  
Author(s):  
Henrique Reis ◽  
Benjamin L. Ervin ◽  
Daniel A. Kuchma ◽  
Jennifer T. Bernhard
Keyword(s):  
Reinforced Concrete ◽  
Guided Waves ◽  
Structural Integrity ◽  
Corrosion Damage ◽  
Propagation Mode ◽  
Reinforcing Steel ◽  
Reinforcing Bars ◽  
Accelerated Corrosion ◽  
Testing Method ◽  
Accelerated Corrosion Tests

Corrosion of reinforced concrete is a chronic infrastructure problem, particularly in areas with deicing salt and marine exposure. To maintain structural integrity, a testing method is needed to identify areas of corroding reinforcement. For purposes of rehabilitation, the method must also be able to evaluate the degree, rate, and location of damage. Toward the development of a wireless embedded sensor system to monitor and assess corrosion damage in reinforced concrete, reinforced mortar specimens were manufactured with seeded defects to simulate corrosion damage. Taking advantage of waveguide effects of the reinforcing bars, these specimens were then tested using an ultrasonic approach. Using the same ultrasonic approach, specimens without seeded defects were also monitored during accelerated corrosion tests. Both the ultrasonic sending and the receiving transducers were mounted on the steel rebar. Advantage was taken of the lower frequency (<250kHz) fundamental flexural propagation mode because of its relatively large displacements at the interface between the reinforcing steel and the surrounding mortar. Waveform energy (indicative of attenuation) is presented and discussed in terms of corrosion damage. Current results indicate that the loss of bond strength between the reinforcing steel and the surrounding concrete can be detected and evaluated.

Passive corrosion control and active corrosion prevention of the reinforced concrete structures by electrochemical chloride removal and inhibitors

2013 ◽  
Vol 61 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Guofu Qiao ◽  
Yi Hong ◽  
Tiejun Liu ◽  
Jinping Ou
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Corrosion Control ◽  
Cell Potential ◽  
Content Type ◽  
Chloride Removal ◽  
Active Corrosion

Purpose – The aim of this paper was to investigate the passive corrosion control and active corrosion protective effect of the reinforced concrete structures by electrochemical chloride removal (ECR) method and inhibitors approach, respectively. Design/methodology/approach – The concentration of aggressive chloride ion distributed from the reinforcing steel to the surface of the concrete cover was analyzed during the ECR processes. Besides, the half-cell potential, the concrete resistance R c , the polarization resistance R p and the capacitance of double layer C dl of the steel/concrete system were used to characterize the electrochemical performance of the concrete prisms. Findings – The effectiveness of ECR could be enhanced by increasing the amplitude of potential or prolonging the time. Inhibitor SBT-ZX(I) could successfully prevent the corrosion development of the reinforcing steel in concrete. Originality/value – The research provides the scientific basis for the practical application of ECR and inhibitors in the field.

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.

scholarly journals Range of dynamic impact of geotechnical works on reinforced concrete structures

2019 ◽  
Vol 97 ◽  
pp. 03026 ◽  
Author(s):  
Anna Wojtowicz ◽  
Jarosław Michałek ◽  
Andrzej Ubysz
Keyword(s):  
Reinforced Concrete ◽  
Statistical Analysis ◽  
Early Stage ◽  
Relative Displacement ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Reinforced Concrete Structure ◽  
Construction Sites ◽  
Dynamic Impact ◽  
Soil Foundation

Impact of geotechnical works related to plunging piles in the ground and modification of the condition of the soil foundation for concrete in the early stage of its bonding, and influence on adhesion of reinforcing steel to concrete can determinate the target capacity of a reinforced concrete structure. Impact of vibrations testing on bond strength is only possible on real designs or models subjected to dynamic impact. The paper presents mechanisms of adherence reduction caused by relative displacement of reinforcing steel and concrete. Moreover, dynamic influences (frequencies and vibration velocities) measured on structures within and around construction sites, where geotechnical works were carried out were also compared. Data obtained after their statistical analysis might become the basis for modelling an experiment.

scholarly journals Accelerated cyclic corrosion tests

2016 ◽  
Vol 60 (2) ◽  
pp. 46-49
Author(s):  
T. Prošek
Keyword(s):  
Quality Control ◽  
Residual Life ◽  
Material Selection ◽  
Salt Spray ◽  
Life Time ◽  
Poor Correlation ◽  
Neutral Salt ◽  
Accelerated Corrosion ◽  
Corrosion Tests ◽  
Accelerated Corrosion Tests

Abstract Accelerated corrosion testing is indispensable for material selection, quality control and both initial and residual life time prediction for bare and painted metallic, polymeric, adhesive and other materials in atmospheric exposure conditions. The best known Neutral Salt Spray (NSS) test provides unrealistic conditions and poor correlation to exposures in atmosphere. Modern cyclic accelerated corrosion tests include intermittent salt spray, wet and dry phases and eventually other technical phases. They are able to predict the material performance in service more correctly as documented on several examples. The use of NSS should thus be restricted for quality control.

Strengthening of the Frame Structure at the Timisoreana Brewery, Romania

2010 ◽  
pp. 57-80
Author(s):  
Corneliu Bob ◽  
Sorin Dan ◽  
Catalin Badea ◽  
Aurelian Gruin ◽  
Liana Iures
Keyword(s):  
Reinforced Concrete ◽  
Load Resistance ◽  
Concrete Cover ◽  
Frame Structure ◽  
Reinforced Concrete Structure ◽  
Existing Structures ◽  
Concrete Carbonation ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Lateral Load Resistance

<p>Many structures built in Romania before 1970 were designed for gravity loads with inadequate lateral load resistance because earlier codes specified lower levels of seismic loads. Some of these structures are still in service beyond their design life. Also, some deterioration was observed in existing structures due to the actions of different hazard factors. This paper presents the case study of a brewery with reinforced concrete framed structure of five storeys and a tower of nine storeys, which has been assessed and strengthened. The brewery and the tower were built in 1961 and an extension in 1971. An assessment performed in 1999 showed up local damages at slabs, main girders, secondary beams, and columns; concrete carbonation; concrete cover spalled over a large surface; complete corrosion of many stirrups and deep corrosion of main reinforcement; and some broken reinforcement. Such damage was caused by salt solution, CO2, relative humidity RH 80%, and temperatures over 40◦C. Also, inadequate longitudinal reinforcement was deduced≈ from the structural analysis. The initial design, done in 1960, was according to the Romanian codes of that time with provisions at low seismic actions. The structural system weakness is due to present-day high seismic actions. The rehabilitation of the reinforced concrete structure was performed by jacketing with reinforced concrete for the main and secondary beams and columns. In 2003, due to continuous operation and subsequent damage of the structure, a new assessment was required. It was found that some beams and one column were characterized by inadequate main and shear reinforcement as well as corrosion of many stirrups at beams. The strengthening solution adopted was based on carbon fibre reinforced polymer composites for beams and column.</p>

scholarly journals STRUCTURAL DESIGN OF POLYMER PROTECTIVE COATINGS FOR REINFORCED CONCRETE STRUCTURES. PART I: THEORETICAL CONSIDERATIONS

2007 ◽  
Vol 13 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Zenonas Kamaitis
Keyword(s):  
Reinforced Concrete ◽  
Protective Coatings ◽  
Concrete Structures ◽  
Concrete Surface ◽  
Polymer Coatings ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Coating Materials ◽  
Barrier Materials ◽  
Mechanism Of Degradation

In a number of situations reinforced concrete structures must be protected by barrier materials to prevent contact with aggressive agents. One of the ways to protect concrete structures from corrosion is to use protective polymer coatings. Polymers as coating materials are not totally resistant and impermeable to all aggressive agents. Gases, vapors and liquids penetrate into a polymer so that the polymer mass swells and eventually disintegrates. However, the penetration/disintegration progresses at a much lower rate than that in the concrete. Surface coatings are able to reduce considerably the penetration, to slow down the rate of deterioration of concrete cover and to overcome most durability problems associated with external attack. In this article the mechanism of degradation of polymer coatings are analyzed. Methodology and predictive models for the degradation over time caused by aggressive actions of polymer coatings are presented. Proposed models can be applied to design of polymer coatings. Such a design of coatings is presented in a simple form for engineering design purposes.

scholarly journals Bond Strengths of Geopolymer and Cement Concretes

2010 ◽  
Vol 69 ◽  
pp. 143-151 ◽  
Author(s):  
Prabir Sarker
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Geopolymer Concrete ◽  
Reinforcing Steel ◽  
Test Results ◽  
Reinforcing Bars ◽  
Pull Out ◽  
Bar Diameter

Geopolymer is an inorganic alumino-silicate product that shows good bonding properties. Geopolymer binders are used together with aggregates to produce geopolymer concrete which is an ideal building material for infrastructures. A by-product material such as fly ash is mixed together with an alkali to produce geopolymer. Current research on geopolymer concrete has shown potential of the material for construction of reinforced concrete structures. Structural performance of reinforced concrete depends on the bond between concrete and the reinforcing steel. Design provisions of reinforced concrete as a composite material are based on the bond strength between concrete and steel. Since geopolymer binder is chemically different from Ordinary Portland Cement (OPC) binder, it is necessary to understand the bond strength between geopolymer concrete and steel reinforcement for its application to reinforced concrete structures. Pull out test is commonly used to evaluate the bond strength between concrete and reinforcing steel. This paper describes the results of the pull out tests carried out to investigate the bond strength between fly ash based geopolymer concrete and steel reinforcing bars. Beam end specimens in accordance with the ASTM Standard A944 were used for the tests. In the experimental program, 24 geopolymer concrete and 24 OPC concrete specimens were tested for pull out. The concrete compressive strength varied from 25 to 55 MPa. The other test parameters were concrete cover and bar diameter. The reinforcing steel was 500 MPa steel deformed bars of 20 mm and 24 mm diameter. The concrete cover to bar diameter ratio varied from 1.71 to 3.62. It was found from the test results that the failure occurred by splitting of concrete in the region bonded with the steel bar, in both geopolymer and OPC concrete specimens. Comparison of the test results shows that geopolymer concrete has higher bond strength than OPC concrete. This suggests that the existing design equations for bond strength of OPC concrete with steel reinforcing bars can be conservatively used for calculation of bond strength of geopolymer concrete.

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