Rebar Corrosion In Concrete Research Articles

Depassivation of Steel Rebar in Concrete Investigated By Electrochemical Impedance

The degradation of concrete and the corrosion of steel-reinforcing bar are serious problem in infrastructures. The electrochemical measurements are useful to evaluate the stability of passive film formed on steel rebar in concrete, which are mainly measurements of corrosion potential [1] and polarization curve. Dawson et al. [2] applied an electrochemical impedance spectroscopy (EIS) to the investigation of rebar corrosion in concrete because the charge transfer resistance at rebar/concrete interface can be determined from the impedance spectrum. Recently, the authors developed an electrode in Fig. 1 as a sensor probe to monitor concrete degradation and rebar corrosion. A couple of electrodes, which were made of same material as steel rebar, can be embedded in concrete structure and complex impedance can be measured continuously on the basis of two-electrode method. The authors’ group has performed the following three types of impedance measurements in order to prove the of the developed sensor probe. (1) Impedance between two electrodes in aqueous solution that simulates the water quality of transition zone (laboratory test). (2) Impedance between two electrodes embedded in the concrete which was fabricated in the laboratory. (3) Field test at bridge pier of the highway in coastal marine environment. It is well known that the rebar corrosion in concrete is strongly influenced by the conditions of cover concrete. Thin water layer is formed at rebar/concrete interface due to water absorption in the concrete. The concrete is good health status and the passive film is formed on steel rebar when the pH of water layer on steel rebar is sufficiently high. The breakdown of passive film occurs by neutralization and enriched chloride ions in the water layer with the degradation of concrete. In this presentation, the authors investigate the critical values of pH and chloride concentration to maintain the passive film on steel rebar and discuss the depassivation mechanisms by the measurements of electrochemical impedance with the developed sensor probe.

A Raman spectroscopy based optical fibre system for detecting carbonation profile of cementitious materials

Sensors demonstrate huge potential in civil engineering for monitoring the health condition and performance of concrete structures. Amongst various chemical deterioration mechanisms causing inadequate durability of concrete structures, carbonation is one of the most severe mechanisms. It occurs from the chemical reactions between intruded CO2 and calcium-bearing phases, hence is accompanied by the formation of calcium carbonate (CaCO3) and the decrease of the alkalinity of concrete pore solution, causing corrosion of rebar in concrete. Thus, detecting carbonation process, especially, determining the carbonation profile (i.e. the content of carbonation products formed against the depth into concrete structure), is of great importance to the diagnosis of the health condition of concrete structures and the prediction of service life. Unfortunately, existing sensors for health monitoring systems suffer from various limitations. Optical fibre Raman technology offers a unique opportunity for developing a novel chemical sensor system capable of monitoring the service-condition of concrete in situ. In the current work, a bespoke ‘coaxial’ optical fibre sensing platform based on Raman spectroscopy was successfully established with a 514.5nm laser. All the optics were tailored for efficiently exciting and receiving signals from cementitious materials, and their diameters were restricted within 0.5in. in order to explore the feasibility of developing an embeddable miniature sensor system in the future. This sensing system was then employed to detect the carbonation mechanism of a plain Portland cement (PC) paste. The calcium carbonate polymorphs as well as the carbonation profile in the PC paste was successfully recognised and established with the results being verified favourably by bench-mounted Raman, X-ray Diffraction (XRD) and Thermogravimetry (TG) analyses. Our results demonstrate a good potential for developing a novel Raman spectroscopy based optical fibre sensor system for monitoring the health condition and the performance of concrete structures in future.

유기계 방청제를 혼입한 표면피복재의 유해이온 침투저항에 관한 실험적 연구

일반적으로 크리트 구조물의 열화를 발생하는 가장 중요한 원인은 탄산화와 염소이온이다. 대체적으로 많은 콘크리트 구조물에서 탄산화와 염소이온으로 인하여 철근이 부식되며 이에 대한 많은 연구가 이루어지고 있다. 특히, 최근에는 보수용으로서 콘크리트 보호용 표면피복재에 방청제를 함침시켜, 염화물을 포함하고 있는 콘크리트 내 철근의 부식을 억제하는 공법도 개발되어지고 있다. 이에, 본 연구에서는 기존 보수재료 보다 부식 억제가 우수하고 열화원인인 <TEX>$CO_2$</TEX> 와 <TEX>$Cl^-$</TEX>를 고정하는 유기계방청제를 혼입한 표면피복재의 특성 평가를 위해 촉진탄산화 및 시차 열 중량분석(TG-DTA), CASS시험를 실시하여 특성을 실험적으로 평가하였다. 실험 결과, TG-DTA 분석과 촉진탄산화를 통하여 유기계방청제 혼입으로 시멘트 콘크리트에 <TEX>$CO_2$</TEX>가 아민유도체와 직접적으로 반응하여 탈 양성자화 되면서 산성상태의 물질을 생성하여 안정화된 상태, 즉 <TEX>$CO_2$</TEX>가 고정화되어 탄산화 억제효과가 있음을 확인 하였다. 또한, CASS실험에서도, <TEX>$Cl^-$</TEX> 고정 특성이 있는 유기계 방청제가 혼입된 표면피복재를 도포한 시험체의 경우, 28일째까지도 적청 발생이 관찰되지 않았으며 염화물에 의한 철근 부식을 방지하는데 우수한 성능으로 가지고 있음을 확인하였다. In general, carbonation and chlorine ions are the most harmful causes of deterioration of concrete structures. Recently, a method has been developed to control the corrosion of rebar in concrete containing chloride by impregnating a Surface coating material with a inhibitor. In this study, accelerated carbonation and differential thermogravimetric analysis (TG-DTA) and CASS tests were carried out to evaluate the characteristics of Surface coatings containing Organic Corrosion inhibitors which are excellent in corrosion inhibition and fix degradation causes <TEX>$CO_2$</TEX> and <TEX>$Cl^-$</TEX>. As a result of the experiment, TG-DTA analysis and accelerated carbonation showed that <TEX>$CO_2$</TEX> was directly reacted with amine derivative in concrete by the incorporation of Organic Corrosion inhibitor. In other words, <TEX>$CO_2$</TEX> was immobilized and carbonation inhibition effect was confirmed. In addition, in the CASS test, the specimen coated with the Surface coating material containing the Organic Corrosion inhibitor with <TEX>$Cl^-$</TEX> fixing property showed no corrosion until the 28th day and had excellent performance in preventing corrosion of a rebar by the chloride ion.

Impedance Measurements to Monitor Concrete Degradation and Rebar Corrosion

The degradation of steel-reinforced concrete is serious problem in infrastructures. It is well known that the rebar corrosion in concrete is strongly influenced by the conditions of cover concrete. Figure 1 shows schemes of interface between steel rebar and concrete. Thin water layer is formed at this interface due to water absorption in the concrete which covers the steel rebar. And this water layer is called “transition zone” in the field of civil engineering. The pH of water at transition zone is high when the concrete is good health status, and the passive film is formed on steel rebar. The breakdown of passive film occurs by neutralization and chloride concentration in the water layer with the degradation of concrete. Corrosion resistance of steel rebar is influenced by the water quality in the transition zone. Thus, we can conclude that rebar corrosion in concrete is electrochemical process at metal/water interface. Electrochemical measurements are useful to investigate the corrosion mechanisms. There are some literatures regarding the electrochemical tests, which are mainly measurements of corrosion potential [1] and polarization curves, to evaluate the stability of passive film formed on rebar in concrete. Dawson et al. [2] applied an electrochemical impedance spectroscopy (EIS) to the investigation of rebar corrosion in concrete because the charge transfer resistance at rebar/concrete interface can be determined from the impedance spectrum. The authors developed an electrode as a sensor probe to monitor concrete degradation and rebar corrosion. A couple of electrodes, which were made of same material as rebar, can be embedded in concrete structure and complex impedance can be measured continuously on the basis of two-electrode method. In this presentation, the authors report the results of three impedance measurements as follows. (1) Impedance between two electrodes in aqueous solution that simulates the water quality of transition zone (laboratory test). (2) Impedance between two electrodes embedded in the concrete which was fabricated in the laboratory. (3) Field test at bridge pier of the highway in coastal marine environment.

Study of Concrete having Industrial Waste as Fine Aggregate Replacement and Generation of Model for Prediction of Compressive Strength Using Response Surface Method

This work focuses on the possibility of optimum utilization of Industrial by-product by replacing the natural sand with Pond Ash and Slag in the concrete. This work also aims in the prediction of 28 days strength using early age measurement of resistivity and compressive strength. Mechanical properties of modified concrete have been obtained and compared with that of the standard mix of concrete. Uniaxial electrical resistivity measurement has been performed on the samples. These observations have been compared with results given by previous researchers. Using these comparison performances based quality control, diffusion of chloride and corrosion of rebar in concrete has been assessed. Further, statistical model has been generated for the prediction of 28 days compressive strength by Response Surface Method (RSM) using early age measurement of resistivity and compressive strength as dependent variables. The results obtained indicate that, for slag model the ultimate strength is not much affected rather resistivity has been significantly improved; consequently it has better quality, reduced corrosion and lower diffusion coefficient. In order to compare the results obtained from the RSM model and experimental method, an error analysis had been performed. The errors are approximately 3.63% for the prediction of 28 days strength.

Monitoring of Corrosion Resistance of Steel in Simulated Concreate Pore Solution By EIS

The method to evaluate the reinforcing steel in concreate have been investigated because the degradation of reinforced concrete is a serious problem in the whole world. An electrochemical impedance spectroscopy (EIS) is the powerful tool to determine the condition of the reinforcing steel in concrete because it is possible to obtain the electrochemical parameters of the reinforcing steel in concrete without its destruction by EIS. Dawson et al. [1] applied EIS to the investigation of corrosion of rebar in concrete. In the present study, we proposed the method to determine the corrosion resistance of reinforcing steel in concrete using the cylindrical steel probes by EIS. Figure 1 shows the cylindrical steel probes developed in the present study. The diameter and thickness of the steel probe is 10 mm and 8 mm respectively. The distance between the steel probes are 50 mm. These probes are embedded in concreate with the reinforcing steel. We expect that the corrosion resistance of the reinforcing steel in concreate can be determined by monitoring of the electrochemical impedance of the cylindrical steel probes. In order to establish the proposed monitoring method, the electrochemical impedance of the cylindrical steel probes were measured in the simulated concreate pore solution. Figure 2 shows the experimental setup of the electrochemical impedance measurement of the cylindrical steel probes in Fig. 1. The electrolyte solution was the saturated Ca(OH)2. The cylindrical steel probes were immersed in the electrolyte solution for 2 days. The air was continuously provided by pump during the immersion of the cylindrical steel probes in the electrolyte solution. The electrochemical impedance was automatically monitored at 10 kHz and 10 mHz using a corrosion monitor (Corp. i-pec, CEM-100A) by two electrode system. The potential amplitude was 10 mV. In addition, the electrochemical impedance measurement was carried out using the Potentiostat (Toyo Corp., Solatron1287) and FRA (Toyo Corp., Solatron1255B) in the frequency range from 10 mHz to 10 kHz at five frequencies per decade with AC amplitude of 10 mV. The pH of the electrolyte solution was measured every 24 hours. The electrochemical impedance of the cylindrical steel probes determined using the corrosion monitor was compared to that measured using FRA. The changes of the charge transfer resistance R ct was discussed by the time variation of pH. Reference [1] J. Dawson, L. Callow, K. Hladky and J. Richardson, Corrosion/78, 125 (1978). Figure 1

EIS Study on Corrosion Mechanisms of Steel Rebars in Concrete

The durability of steel-reinforced concrete is a serious problem that concerns the whole world. It is well known that the corrosion of steel rebar in concrete is strongly influenced by the conditions of cover concrete, namely, water absorption, neutralization and chloride ion permeation. There are some literatures regarding the electrochemical tests, which are mainly measurements of corrosion potential and polarization curves, to evaluate corrosion of rebar in concrete [1,2]. Sagues et al. [3] reported the operation of a macroscopic Kelvin Probe (KP) for contactless measurement of concrete surface potentials. Dawson et al. [4] applied an electrochemical impedance spectroscopy (EIS) to the investigation of corrosion of rebar in concrete because the charge transfer resistance can be determined from the impedance spectrum. Figure 1 shows the scheme of Nyquist plot of electrochemical impedance of steel-reinforced concrete. For example, a capacitive loop related to the time constant of charge transfer resistance and electric double layer capacitance at rebar/concrete interface is observed in the low frequency range. The capacitive loop in the middle frequency range is related to the electric nature of rust or oxide layer formed on rebar surface [5]. McCarter et al. [6] reported that capacitive loop in the high frequency range originated form the dielectric property of concrete absorbing water. In this presentation, we introduce some configurations of electrodes (or probes, sensor) to measure an impedance spectrum of steel-reinforced concrete. And we will discuss the corrosion behavior of rebar in concrete by analyzing the conditions of concrete and rebar/concrete interface by EIS.

Influence of chloride and moisture content on steel rebar corrosion in concrete

Reinforced mortar samples were exposed in humidity chambers with different relative humidity or exposed in cyclic moisture conditions. The rebars were in an “as received” condition meaning that the preexisting oxide scale were intact. The lowest chloride concentration that initiated corrosion was 1% Cl− by mass of cement, corrosion was then observed for samples exposed at 97% relative humidity. It is suggested that the corrosion rate decreases when samples are exposed to a relative humidity lower than 97%. The results indicate that threshold levels should be evaluated at rather humid conditions (97%) despite the fact that the maximum corrosion rate at higher chloride levels is observed in the interval 91–94%. For samples exposed to cyclic moisture conditions, a lower chloride concentration was needed to initiate corrosion compared to samples exposed in static moisture conditions.

Acoustic emission-based mathematical procedure for quantification of rebar corrosion in reinforced concrete

One of the most important causes for deterioration of reinforced concrete structures is corrosion of steel rebar in concrete. Acoustic emission (AE) technique is reported as an effective non-destructive tool for qualitatively identifying the onset of rebar corrosion. The applicability of AE for quantitative assessment of rebar corrosion in concrete is investigated here. Statistical analysis of experimental results under accelerated corrosion confirmed a promising relationship between gravimetrical rebar mass loss and AE measurement. The efficacy of the developed mathematical model was further confirmed under realistic prolonged corrosion exposure. Thus, a new procedure has been developed for quantification of rebar corrosion through experimental verification.

Rebar corrosion effects on structural behavior of buildings

Rebar corrosion in concrete is one of the main causes of reduction of service life of reinforced concrete buildings. This paper presents the influence of rebar corrosion on the structural behavior of reinforced concrete (RC) buildings subjected to strong earthquake ground motion. Different levels of rebar corrosion scenarios were applied on a typical four story RC frame. The deteriorated conditions as a result of these scenarios include loss in cross-sectional area and loss of mechanical properties of the reinforcement bars, loss in bond strength, and loss in concrete strength and its modulus of elasticity. Dynamic analyses of the frame with different corrosion scenarios are performed with selected strong earthquake ground motion records. The influences of degradation in both concrete and reinforcement on structural behavior are investigated by comparing the various parameters of the frame under different corrosion scenarios with respect to each other. The results show that the progressive deterioration of the frame due to rebar corrosion causes serious structural behavior changes such as change in failure mode. The intensity, propagation time, and extensity of rebar corrosion have very important effects on the level of degradation of steel and concrete, as well as on the earthquake behavior of the structure.

A Study on Steel Fiber Influence to Rebar Corrosion in Concrete

In dry-wet cycle chloride environment, the corrosion potential of the SFRC specimens is stable between-300mV to-400mV. And the common concrete specimens were about-500mV, adding steel fibers is higher corrosion potential and lower the corrosion possibility. Steel fiber has effective action on the controlling rebar corrosion and concrete crack. There were no cracks on all the surface of the SFRC specimens. Adding Steel fiber in concrete composed to be a corrosion cell as sacrificial anodes to protected steel rebar as cathode, in some degree to postpone rebar corrosion beginning time and increasing the structure services life.

Investigation of effect of fineness dependent volume of fine aggregate on passive layer formation and corresponding corrosion of steel reinforced concrete using electrochemical approach

This paper aims to determine the effect of the fineness modulus of fine aggregate on the quality and development of passive film and its subsequent effect on the corrosion of reinforced concrete structures. The study uses both electrochemical laboratory controlled experimentation and finite element modelling approach. Corrosion is an electrochemical process that requires an electrolyte for the occurrence of a corrosion reaction. Therefore, it is necessary to calculate the effective corrosion rate with reference to the saturated area of the concrete only when there is corrosion of reinforced concrete structures. Theoretically and numerically, the saturated area depends on the capillary zone porosity, gel zone porosity and degree of saturation in the aggregate free volume of concrete, which is a heterogeneous material. It is thus important to understand the effect of aggregate fineness on the corrosion of steel rebars. Therefore, detailed investigations were conducted using a variety of fine aggregates and combinations thereof. The initiative for this research came from the observation that the interfacial transition zone (ITZ) around the steel bar in concrete does not contain coarse aggregate, but could be surrounded by mortar and not only paste. Hence, the fine aggregate volume may also influence the corrosion rate. Some fine aggregate, which is finer than coarse aggregate, could be present in the vicinity of the steel bar surface, depending on the fineness modulus, which may affect both the development of the passive layer and the corrosion rate. The previous research data in this area were found to be limited. Hence, these factors have been investigated in the present study. Both mortar and concrete prismatic specimens were cast, and the quality of passive layer development and the corrosion severity were compared between specimens to determine the effect of fine aggregate volume with respect to the respective fineness modulus values. The corrosion potential, current and rate values obtained through experimentation showed significant differences in their magnitudes with respect to the variation in the fineness modulus. A directly proportional relation was observed between the fineness modulus of fine aggregate and the corrosion of rebars. Therefore, in the light of the experimental results obtained in this study, a finite element based numerical model incorporating the effect of the fineness modulus of fine aggregate on corrosion of steel rebars in concrete has been developed and successfully verified in this study.

The Corrosion Status of Reinforced Concrete Structure Monitoring by Impact-Echo Method

The paper deals with the study of dominant frequencies of an Impact-Echo method response signal obtained from a reinforced concrete beam with a steel rod diameter of 8 mm. Tension pulse was produced in axis of the rod at one end and detected in axis at opposite end of rod. Dominant frequencies of the response signal will be the main criterions for the reinforced concrete rebar corrosion progress. The article presents the results of measurements obtained after 12 months controlled degradation in aqueous NaCl solution. The results were compared with measurements of electrical resistance of reinforcing steel by using the Thomson double bridge.

Corrosion of rebar in concrete under cyclic freeze–thaw and Chloride salt action

We studied the coupled effects of freeze–thaw (F–T) cycling and chloride on corrosion of rebar in concrete. An ordinary concrete and a ternary-binder concrete were immersed in 3.5wt.% NaCl solution and endured up to 200 F–T cycles. We found: (1) the risk of corrosion of steel reinforcement in concrete remained in the “passive region”, even with increasing F–T cycling, although serious spalling occurred for all concrete specimens; (2) factors that reduce rebar corrosion include lower temperatures, non-wetting phase percolation which blocks harmful chloride penetration, and insufficient oxygen supply; and (3) blends do not seem to improve the resistance to reinforcement corrosion.

AC Impedance and DC Galvanic Current for Monitoring Maturity of Cement Mortar and Rebar Corrosion

The maturity behavior of cement mortar specimens with different concrete additives during the 28 day curing period has been examined using the AC Impedance technique. The main focus of this part of the study is to understand the impedance and capacitance behavior of the steel rebar in cement mortar using different additives during the early stages of hydration process. In this respect, two sets of specimens were prepared: One set consist of two graphite electrodes surrounded by a carbon steel rod for AC Impedance measurements. Another set consisted of two carbon steel setup that has been used for monitoring corrosion of two steel reinforcement bars embedded in cylindrical mortar specimens. The specimens are placed in a salt fog (spray) cabinet for 1,000 hrs.Galvanic current between the two coupled electrodes has been measured using zero resistance ammeter (ZRA) to monitor the extent of corrosion. The in-situ measurement was carried out in a sequential manner over a periodical basis of up to 1,000 hrs of salt fog cabinet exposure. Different mortar mixes were studied including ground granulated blast furnace slag (GGBS) and silica fume (microsilica) as additives and calcium nitrite as corrosion inhibitor and chloride as a contamination species. This data helps in understanding the corrosion activities at the rebar-concrete when interface combined with salt fog test according to (ASTM B117), which can be further correlated with the atmospheric and marine corrosion of steel rebars in concrete. The overall results have indicated the tendency of the admixture to show different hydration processes during the early stages of concrete curing. The interfacial impedance spectrums and galvanic current testing clearly identifies and documents this process for each material.

Using of Impact-Echo Methods to Assessment of Reinforced Concrete Structures Corrosion

The paper deals with the study of dominant frequencies of an Impact-Echo method response signal obtained from a reinforced concrete beam with a steel rod diameter of 8 mm. Tension pulse was produced in axis of the rod at one end and detected in axis at opposite end of rod. Dominant frequencies of the response signal will be the main criterions for the reinforced concrete rebar corrosion progress. The article presents the results of measurements obtained after 12 months controlled degradation in aqueous NaCl solution. The results were compared with measurements of electrical resistance of reinforcing steel by using the Thomson double bridge.

Long period fiber grating transverse load effect-based sensor for the omnidirectional monitoring of rebar corrosion in concrete

From the angle of sensitivity of the long period fiber grating (LPFG) resonant transmission spectrum, we demonstrate the sensitivity of LPFG resonance peak amplitude changing with transverse loads. The design of a resonant peak modulation-based LPFG rebar corrosion sensor is described by combining the spectral characteristics of LPFG with the expansion state monitoring of rebar corrosion. LPFG spectrum curves corresponding with different rebar corrosion status of the environment under test are captured by the monitoring technique of LPFG transmission spectra, and the relationship between the resonance peak amplitude change and the state of rebar corrosion is obtained, that is, the variation of LPFG resonance peak amplitude increases with the intensifying of the degree of rebar corrosion. The experimental results numerically show that the sensor response has good regularity for a wide range of travel.

The Influence of Inertia Weight on Particle Swarm Optimization in Boundary Element Inverse Analysis for Rebar Corrosion Detection

Particle Swarm Optimization (PSO) has been applied as optimization tool in various engineering problems. Inverse analysis is one of the potential application fields for PSO. In this research, the behavior of PSO, related to its inertia weight, in boundary element inverse analysis for detecting corrosion of rebar in concrete is studied. Boundary element inverse analysis was developed by combining BEM and PSO. The inverse analysis is carried out by means of minimizing a cost function. The cost function is a residual between the calculated and measured potentials on the concrete surface. The calculated potentials are obtained by solving the Laplace’s equation using BEM. PSO is used to minimize the cost function. Thus, the corrosion profile of concrete steel, such as location and size, can be detected. Variation in its inertia weight was applied to analyze the behavior of PSO for inverse analysis. The numerical simulation results show that PSO can be used for the inverse analysis for detecting rebar corrosion by combining with BEM. Also, it shows different behavior in minimizing cost function depending on inertia weight.

A Study on Carbon Fiber Influence to Rebar Corrosion in Concrete

Rebar corrosion test of Carbon Fiber Reinforced Polymer (CFRP) concrete was did. Carbon fiber in concrete improved the compression strength of the concrete, but width and number of concrete cracks was not reduced, carbon fiber has not obvious act for improving concrete corrosion crack behavior. CFRP concrete Corrosion potential was a little high than common concrete, carbon fiber has not obvious act for improving concrete behavior in protecting steel beyond corrosion. The porosity of the carbon fiber reinforced polymer concrete was twice of the common concrete, carbon fiber added to concrete lead to increase porosity and maybe decrease concrete behavior in protecting the embedded steel in corrosion.

열유도 장치와 적외선 열화상을 이용한 철근부식탐지 비파괴 평가기법

콘크리트내의 철근의 부식은 열화와 콘크리트 구조물의 조기파괴의 주된 원인이 된다. 본 연구에서는 비파괴 기법 중 전자기적 열유도방법과 적외선 열화상기법을 이용한 철근부식평가가 시도되었는데, 부식 또는 비부식된 철근의 열특성 차이를 이용한 것이다. 본 논문은 이러한 개념을 배경으로 수행한 실험적 연구이며, 유도전류를 통해 콘크리트 표면으로부터 내부 철근을 가열하고 외부의 적외선 카메라를 이용하여 표면의 온도변화를 관측한다. 피복두께가 다른 콘크리트 시편은 앞면과 배면의 피복두께를 동일하게 제조하여 앞면에서 가열과 배면에서의 온도측정을 동시에 할 수 있도록 고안되었다. IC (Impressed Current) 방법을 통하여, 철근 부식을 촉진하였으며, 적외선 화상을 통하여 온도가열과 냉각을 전 시험과정에 걸쳐 측정하였다. 본 실험을 통하여 부식/비부식 철근의 뚜렷한 온도변화를 확인하였으며, 부식된 시편에서 빠른 온도증가속도 및 냉각속도를 평가하였다. 본 연구는 콘크리트 매립철근의 비파괴적인 부식탐지의 가능성을 보여주고 있다. Steel corrosion in concrete is a main cause of deterioration and early failure of concrete structures. A novel integration of electromagnetic heat induction and infrared (IR) thermography is proposed for nondestructive detection of steel corrosion in concrete, by taking advantage of the difference in thermal characteristics of corroded and non-corroded steel. This paper focuses on experimental investigation of the concept. An inductive heater is developed to remotely heat the embedded steel from concrete surface, which is integrated with an IR camera. Concrete samples with different cover depths are prepared. Each sample is embedded with a single rebar in the middle, resulting an identical cover depth from the front and the back surfaces, which enable heat induction from one surface and IR imaging from the other simultaneously. The impressed current (IC) method is adopted to induce accelerated corrosion on the rebar. IR video images are recorded during the entire heating and cooling periods. The test results demonstrate a clear difference in thermal characteristics between corroded and non-corroded samples. The corroded sample shows higher rates of heating and cooling than those of the non-corroded sample. This study demonstrates a potential for nondestructive detection of rebar corrosion in concrete.