Concrete structure is a construction material with durability and cost-benefit, however the corrosion in embedded steel causes a critical problem in structural safety. This paper presents an evaluation of chloride resistance and pull-off performance with various corrosion level. For the work, OPC(Ordinary Portland Cement) concrete and GGBFS(Ground Granulated Blast Furnace Slag) concrete are prepared with normal steel. Artificially notch induced FRP Hybrid Bar is also prepared and embedded in OPC concrete and accelerated corrosion test is performed. Through the test, FRP Hybrid Bar with notch is evaluated to have insignificant effect on pull-off capacity when corroded steel shows only 21% level of pull-off capacity. Furthermore GGBFS concrete with normal steel shows over 70% level of pull-off capacity due to reduced corrosion currency.

In this study, Corrosion behavior in mortar was observed by the passage of time by using EIS method. As a result of EIS experiment, equivalent circuit and changes of Impedance parameter could be observed. In addition, it was confirmed that impedance of rebar in mortar and corrosion rate according to the amount of NaCl were different.

In this study, finite element analysis was performed to analyze the load carrying capacity of corroded plate girder. Consequently, web buckling load indicated drastic reduction in corrosion thickness less than 1 millimeters. Therefore, if the plate girder is seriously corroded to time of drastic reduction of web buckling load, it will need appropriate maintenance and reinforcement to guarantee of safety.

Steel is a common structural material that is used for bridges, buildings, railroad tracks, wind towers, offshore platforms, and many other applications. Steel naturally corrodes in different atmospheric environments, which results in costs for corrosion protection, prevention and maintenance. The corrosion on steel elements is identified by optical examination, which does not provide information on the material characteristics. Studies have shown that Raman spectroscopy can identify the corrosion products of steel and differentiate between iron oxides and hydroxides. The purpose of this experiment is to validate the use of Raman spectroscopy in accurately identifying corrosion material on steel without a protective coating.

Development of appropriate construction technology at frozen soil environments for developing resources is essential. However, cathodic protection technology using monitoring at frozen soil environments is lack. In this study, we want to build a real-time monitoring system at frozen soil environments through corrosion monitoring using type of gavanic metal

RC(Reinforced Concrete) 부재는 인장영역에서 보강재가 하중을 지지해야 하므로, 철근부식은 내구성 뿐 아니라 안전성에서도 매 우 중요하다. 본 연구에서는 최근 개발된 FRP Hybrid Bar와 일반 철근을 매립한 RC 보부재를 제작하였으며, ICM(Impressed Current Method) 를 적용하여 철근부식을 촉진시켰다. 기존의 이론식인 Faraday 법칙을 이용하여 부식량을 평가하였으며, 일반설계강도를 가진 콘크리트 보부 재에 대하여 휨시험을 수행하였다. 일반 철근에서는 부식량이 4.9∼7.8% 수준으로 평가되었으며 이에 따른 휨 저항능력은 -25.4∼-50.8% 수준 으로 감소하였다. FRP Hybrid Bar를 매립한 RC 보에서는 부식과 휨 저항 감소가 평가되지 않았는데, 이는 에폭시 도료로 코팅된 철근의 우수 한 내부식성에 기인한다. 촉진 부식실험에서는 FRP Hybrid Bar의 우수한 내부식성 및 부착성능을 확인하였는데, 실용화를 위해서는 장기적인 침지를 통한 내구성 평가가 필요하다고 판단된다.

본 실험 논문은 초단유리섬유(milled glass fibers)가 혼입된 PSC용 그라우트 몰탈의 강재부식성능을 평가하였다. 초단유리섬유를 함유한 배합이 PSC 그라우트 몰탈로서 소요성능을 만족시키는지를 확인하기 위하여 유하시간, 블리딩 및 압축강도를 측정하였다. 초단유리 섬유를 함유한 몰탈의 부식저항 성능은 염소이온 확산시험, 몰탈 흡수시험과 표면전기저항 측정 결과에 근거하여 수행되었다. 시험결과, 초단 유리가 혼입된 모든 배합은 OPC만 사용된 배합에 비하여 그라우트의 부식저항성능을 개선시키는 것으로 확인되었다. 다만, 초단유리섬유를 사용함으로서 유하시간은 단축되지만 블리딩이 발생하여 소요성능을 만족하지 못하는 것으로 확인되었다. 그러므로 PSC 그라우트에 적합한 초단유리섬유배합이 되기 위해서는 물-바인더비의 조정이 필요한 것으로 판단된다.

A total of 15 different solid waste materials were analyzed for toxic substances such as Pb, Cd, Cu, As, Hg, Cr (VI)by the Korean standard leaching test and as total content. These wastes were also tested for corrosivity characteristicsusing an ionic electrode for pH and a circular steel for corrosion rate. Based on the results of the leaching test, the solidwaste samples did not exceed the regulated leaching levels. Thus, the analyzed wastes may be classified and managedas general industrial waste, not hazardous waste. Four solid waste samples were greater than total content levels proposedby other previous study. In case of the corrosive property of the solid waste leachate (1:2.5), the highest pH of the wastesample exhibited the lowest corrosion rate of 0.065mm/yr. However, the waste samples with low pH values exhibiteda greater corrosion rate. It is difficult to determine the correlation between pH and corrosion rate of the solid waste leachate.Therefore, the testing of the solid wastes are needed to further investigate the corrosion of a glass electrode method ratherthan the corrosion rate measurement. In the future, other hazardous properties such as ecotoxicity should be also examinedto properly manage the solid waste materials.

A cartridge type sensor head was fabricated to detect the level of corrosion in steel cables with consistent or varying cross sections by assessing the LMA (Loss of Metallic Area) damage. Two coil sensor cartridges were made to cater to cables with up to 70mm and 150mm. The developed system was verified through lab experiment using a tapered steel cable specimen, and through a field test conducted in cable bridge. The result showed that the developed system is capable of assessing a cable with varying cross section.

Many researchers have defined critical chloride content as a specific value. The studies reporting critical threshold chloride content have involved the experimental measurement of the average amount of the total chloride content. The studies have tried to define the critical chloride content within the scope of their experimental concrete mix proportion at arbitrary time. However, there is no agreement on its value. The purpose of this study is to explore the combined effect of oxygen and chloride on reinforcement corrosion. In the experimental recipe, water soluble oxygen is taken into account to define the critical chloride content. Corrosion current density of reinforcement was measured by linear polarization resistance method.

This study, depending on the concrete mix material by performing the test on the basis of the wet and dry condition and freeze-thaw, and to elucidate the difference in the corrosion initiation time of there steel, in both environments, it is an object of correlation coefficient derived through the results of the accelerated corrosion test in a laboratory corrosion period of the structure of the marine environment.

For steel structure, corrosion damage should be considered because it is related to durability and structural performacne of steel structure. In this study, therefore, compressive loading tests of inclined steel members were conducted to examine change in the compressive strength depending on corrosion damage applied by mechanical process. From loading tests, compressive behavior and change in structural capacity of inclined steel members with corrosion were compared.

The tap water is generally known to be corrosive in the pH range at 6.5 ~ 7.5. And the degree of corrosion varies depending on the types of raw water such as river surface water or lake water of the dam. Although several corrosion index represents the corrosivity of tap water, the typical corrosion indexes such as Langelier saturation index (LI) and calcium carbonate precipitation potential (CCPP) were calculated to monitoring the corrosive water quality about raw and tap water in water distribution system. To control the corrosive water quality, the correlation between corrosion index and water quality factors were examined. In this study, corrosion index (LI, CCPP) and the pH was found to be most highly correlated.

In the paper, newly invented FRP Hybrid Bar and normal steel are embedded in RC beam member, and ICM(Impressed Current Method) is adopted for corrosion acceleration. Corrosion amount level of 4.9∼7.8% are measured in normal RC member and the related reduction of flexural capacity is measured to –25.4∼-50.8%. But, durability evaluation through long-term submerged condition is required for actual utilization.

In the paper, accelerated corrosion test for RC (Reinforced Concrete) samples with normal steel and FRP Hybrid Bar are performed and their flexural capacity is evaluated. Furthermore UV(Ultrasonic Velocity) measurement is attempted for analysis of variation of UV due to corrosion conditions. For commercial production of FRP Hybrid Bar, bond strength evaluation through long-term submerged corrosion test is required.

The concrete frames are deteriorated by the corrosion of reinforcement bars. To consider the corrosion effect on the seismic performance of concrete frames, the probabilistic approach method such as the Monte Carlo simulation (MCS) is utilized. However, MCS has a weakness that a lot of computation time is required. In this study, the evaluation method for the seismic performance of chloride-corroded reinforced concrete moment frames using multi-cores is presented to reduce the computation time.

The volume expansion of corroded steel reinforcement produces tensile stress on the surrounding concrete, which causes splitting cracking of concrete cover, and deteriorates the service ability and durability of reinforced concrete(RC) members. In addition, since the steel corrosion induces bond strength degradation between steel bar and concrete, the structural performance of RC members can be deteriorated significantly. In this study, the theoretical study was performed to probe the mechanism of the bond strength reduction due to steel corrosion. The bond strength between corroded steel bar and concrete was calculated by mathematically formulating the expansion pressure of corroded steel reinforcement. The proposed model was verified by comparing with the existing test results, and it showed that the proposed model estimate the bond strength reduction of corroded RC elements very closely.

Existing nondestructive test methods used to measure reinforcement corrosion is based on qualitative measurement of corrosion, and it has many difficulties of use because many equipment and measurement stages are required for application at actual sites. Accordingly, this study was conducted to estimate reinforcement corrosion of concrete structures using infrared thermography method as a method of measuring reinforcement corrosion in concrete. As for the specimen was to measure reinforcement corrosion, D13 reinforcement with size of 200×150×180mm was buried at length of 250mm for covering depth of 20mm and 40mm. Accelerated reinforcement corrosion test was carried out after placement of concrete. As a result of measuring reinforcement corrosion using infrared thermography method, temperature difference of 1~3°C was shown depending on the corrosion stage. There was a correlation in which temperature decreased according to chloride content. Infrared thermography method was confirmed as a useful method for measurement of reinforcement corrosion inside concrete.

Durability and structural safety of steel structure are severely affected by corrosion caused by deicer material as well as by airborne chlorides in the marine environment. In this study, based on analysis of current status it is suggested that deterioration and durability reduction by the environmental factor such as chlorides should be more reasonably taken into consideration for the accurate inspection and condition evaluation of steel structures.