• Corrosion Science and Technology
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• v.9 no.1
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• pp.39-47
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• 2010

Galvanic coupling between GECM(graphite epoxy composite material) and metallic materials can facilitate corrosion of metals and alloys because GECM is noble and electrically conductive. Galvanic corrosion is affected by many factors including metallic materials, area ratio, surface condition, and corrosivity. This work aims to evaluate the effect of area ratio on galvanic corrosion between GECM and several metals. In the case of glavanic coupling of carbon steel and Al to GECM, corrosion rate increased with increasing area ratio. Corrosion rate of sensitized STS 316S stainless steel decreased a little at an area ratio 1:1 but increased at an area ratio 30:1. It is considered to be due to that area ratio affects galvanic corrosion more in less corrosion resistant alloys. However, in case of STS 316 and Ti, galvanic coupling reduces corrosion rate by the formation of passive film.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.86-89
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• 2003

It is recognized that reinforcement corrosion is the main distress behind the present concern regarding concrete durability. In this study, to confirm corrosion of reinforced concrete affected by thickness of cover, kinds of surface coating, measured electric potential, ratio of corrosion area, weight reduction, corrosion velocity of steel bar under environment of complex deterioration. The results showed that an increase in age also increases corrosion of steel bar. Ratio of corrosion area is largely related to ratio of weight reduction. as well, corrosion of steel bar by thickness of cover is superior to l0mm thick than 20mm thick. It showed that an increase in thickness of cover prevent steel bar from deteriorating. The results of this study showed that corrosion velocity was affected by thickness of cover, kinds of surface coating. data on the development of corrosion velocity made with none, organic B, organic A, inorganic B, and inorganic A is shown.

• Nuclear Engineering and Technology
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• v.25 no.4
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• pp.507-514
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• 1993

Titanium tubes have recently been used in condensers of nuclear power plants since titanium has very good corrosion resistance to seawater. However, when it is connected to Cu alloys as tube sheet materials and these Cu alloys are connected to carbon steels as water box materials, it makes significant galvanic corrosion on connected materials. It is expected from electrochemical tests that the corrosion rate of carbon steel will increase when it is galvanically coupled with Ti or Cu in sea water and the corrosion rate of Cu will increase when it is coupled with Ti, if this couple is exposed to sea water for a long time. It is also expected that the surface area ratios, R$_1$(surface area of carbon steel/surface area of Ti) and R$_2$(surface area of carbon steel/surface area of Cu) are very important for the galvanic corrosion of carbon steel and that these should not be kept to low values in order to minimize the galvanic corrosion on the carbon steel of the water box. Immersed galvanic corrosion tests show that the corrosion rate of carbon steel is 4.4 mpy when the ratio of surface area of Fe/ surface area of Al Brass is 1 while it is 570 mpy when this ratio is 10$^{-2}$ . The galvanic corrosion rate of this carbon steel is increased from 4.4 mpy to 13 mpy at this area ratio, 1, when this connected galvanic specimen is galvanically coupled with a Ti tube. This can be rationalized by the combined effects of R$_1$ and R$_2$ on the polarization curve.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.325-333
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• 1998

Under the seawater environment, the reinforced concrete structure is deteriorated due to physical and chemical attacks. The main deterioration mechanism is the chloride corrosion of reinforcing steel. The corrosion inhibitors have been used to protect the rebars from corrosion which are susceptible to chlorides in concrete. However, there is not clear conclusion about corrosion inhibitors yet. In this study, it is made the accelerated experiment with 3 kinds of corrosion inhibitors for various chloride ingresses. It is estimated corrosion inhibitors that inhibitors by Half-Cell Potential, corrosion area ratio and weight loss ratio. It is concluded that inhibitors are not effective to corrosion inhibition for excessive chloride ingress. However, the effect of inhibition is directly proportional ot contents of corrosion inhibitors in some chloride ingress.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.761-766
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• 2002

This paper was peformed to verify the effect that granulated blast furnace slag gets in reinforcement corrosion resistance about chloride ion that invade from outside. An experiment accelerated for the reinforcement corrosion through repeat of brine digestion and dry. Reinforcement corrosion investigated half cell potential method of measurement by ASTM C876 and corrosion area ratio. If granulated blast furnace slag metathesis ratio is high generally that looked the corrosion of reinforcement decreasing as a result that evaluate reinforcement corrosion by ASTM C876 canon in this research. It showed high resistance about reinforcement corrosion that use normal portland cement and increase the metathesis rate of granulated blast furnace slag, as a result that evaluate metathesis rate effect of granulated blast furnace slag according to cement kind. when the test piece split destroying, area rate of reinforcement corrosion showed about result of half cell potential measurement.

• Corrosion Science and Technology
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• v.22 no.1
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• pp.55-63
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• 2023

The aim of this study was to propose a multiple linear regression (MLR) equation to predict ultimate tensile strength (UTS) of 316L stainless steel with unspecified pit corrosion. Tensile specimens with pit corrosion were prepared using a potentiostatic acceleration test method. Pit corrosion was characterized by measuring ten factors using a confocal laser microscope. Data were collected from 22 tensile tests. At 85% confidence level, total pit volume, maximum pit depth, mean ratio of surface area, and mean area were significant factors showing linear relationships with UTS. The MLR equation using these three significant factors at a 85% confidence level showed considerable prediction performance for UTS. Determination coefficient (R²) was 0.903 with training and test data sets. The yield strength ratio of 316L stainless steel was found to be around 0.85. All specimens with a pit corrosion presented a yield ratio of approximately 0.85 with R² of 0.998. Therefore, pit corrosion did not affect the yield ratio.

• Magazine of the Korea Concrete Institute
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• v.6 no.2
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• pp.129-137
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• 1994

This study was performed for the purpose of obtaining the fundamental data to establish the criterion of concrete deterioration and presuming steel corrosion of concrete structures under the environment of seawater. Steel embedded concrete specimens were exposed in seawater for 1year. The soluble chloride content in concrete, corrosion potential and steel corrosion were considered. The results show that soluble chloride content in concrete was decreased with lower water-cement ratio and with mineral admixtures. Half-cell potential is reduced with steel corrosion. Corrosion area ratio is correlative with half-cell potential.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.04a
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• pp.148-151
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• 1994

Up to now, sea sand without complete removal of salt is being used in the construction works because there is little satisfactory counterplan for the substitute aggregate. In the case that such sea sand is used in the reinforced concrete, the residual salt gives rise to deterioration phenmenon and iron corrosion, reducing durability of the ferro-concrete structures. The paper, an experimental study on the effect of corrosion protection by tighting concrete used SF and FA, is to investigate general steel bar's corrosion and to develop concrete using sea sand economically after it is analyzed and examinated ratio of the corrosion area affected by the autoclave cycle. As a test results, as for corrosion area ratio, it is very effective to use admixrutes such as SF and FA which decrease corrosion area remarkably with increasing the amounts of admixtures. Accordingly the use of admixtures is advantageous for tightening concrete and has an effect of salt damage prevention and rust protection in concrete used sea sand.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.85-90
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• 1993

This study was performed for the purpose of obtaining the fundamental data to establish the criterion of concrete deterioration and presuming steel corrosion of concrete structures under the environment of seawater. It was exposed in seawater for 1 year that steel was embedded in the concrete specimen. The diffusion coefficients of concrete, corrosion potential and steel corrosion were considered. The results show that corrosion potential is reduced according to steel corrosion and corrosion area ratio is correlative with diffusion coefficients of concrete.

• Computers and Concrete
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• v.4 no.5
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• pp.403-424
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• 2007

The investigation of corrosion effects on the tensile behavior of reinforced concrete (RC) members is very important in region prone to high corrosion conditions. In this article, an experimental study concerning corrosion effects on tensile behavior of RC members is presented. For this purpose, a comprehensive experimental program including 58 cylindrical reinforced concrete specimens under various levels of corrosion is conducted. Some of the specimens (44) are located in large tub containing water and salt (5% salt solution); an electrical supplier has been utilized for the accelerated corrosion program. Afterwards, the tensile behavior of the specimens was studied by means of the direct tension tests. For each specimen, the tension stiffening curve is plotted, and their behavior at various load levels is investigated. Average crack spacing, loss of cross-section area due to corrosion, the concrete contribution to the tensile response for different strain levels, and maximum bond stress developed at each corrosion level are studied, and their appropriate relationships are proposed. The main parameters considered in this investigation are: degree of corrosion ($C_w$), reinforcement diameter (d), reinforcement ratio (${\rho}$), clear concrete cover (c), ratio of clear concrete cover to rebar diameter (c/d), and ratio of rebar diameter to reinforcement percentage ($d/{\rho}$).