Evaluation of rebar corrosion in reinforced concrete under freeze-thaw environment and protection measures

Purpose – Rebar corrosion in reinforced concrete is the major reason for the durability degradation, especially under harsh environment. This paper presents an experiment conducted to investigate the influence of freeze-thaw cycles on the rebar corrosion in reinforced concrete. The purpose of this paper is to provide fundamental information about rebar corrosion under frost environment and improvement measures. Design/methodology/approach – The related elastic modulus and compressive strength of different concrete specimens were measured after different freeze-thaw cycles. The accelerated rebar corrosion test was carried out after different freeze-thaw cycles; additionally, the value of calomel half-cell potential was determined. The actual rebar corrosion appearance was checked to prove the accuracy of the results of calomel half-cell potential. Findings – The results show that frost damage aggravates the rebar corrosion rate and degree under freeze-thaw environment; furthermore, the results become more obvious with the freeze-thaw cycles increasing. Mixing the air-entrained agent into fresh concrete to prepare air-entrained concrete, increasing the cover thickness and processing the surface of concrete with a waterproofing agent can significantly improve the resistance to rebar corrosion. From the actual appearance of rebar corrosion, the results of calomel half-cell potential can well reflect the actual rebar corrosion in reinforced concrete. Originality/value – The durability of reinforced concrete is mainly determined on chloride penetration that brings about rebar corrosion in chloride environments. Furthermore, the degradation of concrete durability becomes more serious in the harsh environment. As the concrete exposure to the freeze-thaw cycles environment, the freeze-thaw cycles accelerate the concrete damage, and the penetration of chloride into the concrete becomes easier because of the growing pore and crack sizes. In addition, rebar corrosion caused by chloride is one of the major forms of environmental attack on reinforced concrete. The tests conducted in this paper will describe the rebar corrosion in reinforced concrete under freeze-thaw environment.

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

Anti-Corrosion Methods and Materials ◽

10.1108/acmm-03-2012-1156 ◽

2013 ◽

Vol 61 (1) ◽

pp. 32-37 ◽

Cited By ~ 3

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.

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Compensated half-cell potential technique for NDE of rebar corrosion

Non-Destructive Testing in Civil Engineering 2000 ◽

10.1016/b978-008043717-0/50066-0 ◽

2000 ◽

pp. 615-624 ◽

Cited By ~ 1

Author(s):

M. Ohtsu ◽

Y. Tomoda

Keyword(s):

Half Cell ◽

Cell Potential ◽

Rebar Corrosion

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Prediction of residual flexural strength of corroded reinforced concrete beams

Anti-Corrosion Methods and Materials ◽

10.1108/acmm-11-2015-1599 ◽

2017 ◽

Vol 64 (1) ◽

pp. 69-74 ◽

Cited By ~ 10

Author(s):

Shamsad Ahmad

Keyword(s):

Reinforced Concrete ◽

Flexural Strength ◽

Current Density ◽

Empirical Model ◽

Corrosion Current Density ◽

Concrete Beams ◽

Corrosion Current ◽

Reinforced Concrete Beams ◽

Content Type ◽

Rebar Corrosion

Purpose This study aims to make an effort to develop a model to predict the residual flexural strength of reinforced concrete beams subjected to reinforcement corrosion. Design/methodology/approach For generating the required data to develop the model, a set of experimental variables was considered that included corrosion current density, corrosion duration, rebar diameter and thickness of concrete cover. A total of 28 sets of reinforced concrete beams of size 150 × 150 × 1,100 mm were cast, of which 4 sets of un-corroded beams were tested in four-point bend test as control beams and the remaining 24 sets of beams were subjected to accelerated rebar corrosion inducing different levels of corrosion current densities for different durations. Corroded beams were also tested in flexure, and test results of un-corroded and corroded beams were utilized to obtain an empirical model for estimating the residual flexural strength of beams for given corrosion current density, corrosion duration and diameter of the rebars. Findings Comparison of the residual flexural strengths measured experimentally for a set of corroded beams, reported in literature, with that predicted using the model proposed in this study indicates that the proposed model has a reasonably good accuracy. Originality/value The empirical model obtained under this work can be used as a simple tool to predict residual flexural strength of corroded beams using the input data that include rebar corrosion rate, corrosion duration after initiation and diameter of rebars.

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Analysis of half-cell potential measurement for corrosion of reinforced concrete

Construction and Building Materials ◽

10.1016/j.conbuildmat.2003.10.004 ◽

2004 ◽

Vol 18 (3) ◽

pp. 155-162 ◽

Cited By ~ 46

Author(s):

Veerachai Leelalerkiet ◽

Je-Woon Kyung ◽

Masayasu Ohtsu ◽

Masaru Yokota

Keyword(s):

Reinforced Concrete ◽

Half Cell ◽

Cell Potential ◽

Potential Measurement

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Effect of Interrupting Electricity Period on Electrochemical Chloride Extraction of Reinforced Concrete

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.754-755.342 ◽

2015 ◽

Vol 754-755 ◽

pp. 342-347

Author(s):

Mien Van Tran ◽

Dong Viet Phuong Tran ◽

Mohd Mustafa Al Bakri Abdullah

Keyword(s):

Reinforced Concrete ◽

Corrosion Rate ◽

Current Density ◽

Concrete Structure ◽

Chloride Concentration ◽

Steel Reinforcement ◽

Reinforced Concrete Structure ◽

Half Cell ◽

Cell Potential ◽

Electrochemical Chloride Extraction

Electrochemical chloride extraction – ECE is an effective method to rehabilitate reinforced concrete structure, which has been corroded. This study investigated concentration of chloride remained in concrete and half-cell potential of the steel reinforcement after ECE using interrupting period of electricity current. Efficiency of ECE using Ca (OH)2was surveyed with two current density of 0.5 and 1A/m2. In this study, ECE treatment was proceeded intermittently in approximately 8 weeks. Results pointed out that chloride concentration decreased to 30 – 60% significantly, especially at in the vicinity of reinforcing steel. Simultaneously, half-cell potential of the steel reinforcement after 4 weeks halted treatment stabilizes in low-corrosion rate.

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