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.

Accelerated corrosion investigation of axially loaded reinforced concrete elements

2014 ◽  
Vol 61 (4) ◽  
pp. 215-223 ◽  
Author(s):  
Christos Zeris ◽  
George Batis ◽  
Vassilios Mouloudakis ◽  
John Marakis
Keyword(s):  
Reinforced Concrete ◽  
Axial Load ◽  
Load Capacity ◽  
Axial Loading ◽  
Load Level ◽  
Concrete Cover ◽  
Chloride Ingress ◽  
Reinforced Concrete Column ◽  
Accelerated Corrosion ◽  
Content Type

Purpose – This paper aims to present results of an experimental investigation on a series of scaled reinforced concrete column elements which were subjected to chloride exposure under accelerated conditions under a concurrent service axial load, over a period. In the presence of an axial load, directed microcracks of increasing density and width are introduced in the concrete mass, depending on the axial load level. Such cracks are believed to enhance the intrusion rate of chlorides in the concrete, relative to what is obtained in the normally performed unloaded specimen tests. Design/methodology/approach – Eighteen column specimens were tested over two chloride exposure periods, of duration up to a maximum of six months. Three different service axial load levels were considered, namely, none, 22 per cent and 43 per cent of the normalized axial load capacity of the columns. Findings – The results indicate that the specimens loaded to the higher axial load, which closely resembles actual service situation of such type of elements, exhibited up to ten times faster rates of induced current flow under a constant applied voltage of 500 mV, compared to the unloaded and less loaded specimens. Practical implications – It is proven that the presence of axial load influences the rate of chloride ingress in columns and, therefore, should be taken into account in estimating the concrete cover of such elements in durability design. Originality/value – The influence of axial loading on corrosion rate has not been considered in published experimental and analytical studies of chloride ingression. These studies have typically so far considered the accelerated corrosion of unloaded column specimens.

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

Accelerated corrosion tests of precoated sheet steels for automobiles

1985 ◽  
Vol 24 (3) ◽  
pp. 378-384 ◽  
Author(s):  
Michael R. Lambert ◽  
Herbert E. Townsend ◽  
Robert G. Hart ◽  
Daniel J. Frydrych
Keyword(s):  
Accelerated Corrosion ◽  
Corrosion Tests ◽  
Sheet Steels ◽  
Accelerated Corrosion Tests

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.

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