• Proceedings of the Korea Concrete Institute Conference
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• 1992.10a
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• pp.88-93
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• 1992

근래 들어 철근 콘크리트에 있어서의 철근 부식이 관심의 대상이 되고 있는데 그 이유는 이 현상이 실제 구조물에서 광범위하게 발생함이 확인되었고 이로 이한 보수비용이 급증하였기 때문이다. 철근의 부식이 처음 거론된 것은 해양구조물과 내화학성 구조물에서였고 최근 들어서는 교량상판, 주차공간 등 염기에 노출되어 철근 부식이 우려되는 각 종의 구조물에 광범위하레 그 대책이 연구되기에 이르렀다. 이와 같은 철근부식의 제어방법으로는 첫째로 콘크리트의 수밀화를 들 수 있고 다음으로 콘크리트의 표면을 처리하거나 피복두께를 늘리는 방법이 있다. 마지막으로 철근 자체에 방청성능을 직접 부여하여 철근의 부식을 방지하고자 하는 방법을 들 수 있다. 본 연구는 이러한 대책중에서 가장 적극적인 방법에 속하는 에폭시 도포 철근의 기본적인 방청성능을 고찰하기 위해 수행되었다.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.355-358
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• 1999

In recent times, large strands have become increasingly popular in the pretensioned prestressed industry and have found wide applications in varying geometries of sections. However, use of such elements and their behavior in several situations have been questioned with respect to anchoring of these strands in concrete. In addition, the experimental results available on bond are limited and information relating to large strands is rare. This study was conducted to determine the influence of some of the inadequately examined properties on transfer length of prestressing strand. The principle variables considered were strand size, concrete strength and clear bottom cover. The experimental results indicate clearly that concrete strength at transfer and cover size influence transfer length significantly. An attempt was made to suggest prediction equation for transfer length including above parameters.

• Magazine of the Korea Concrete Institute
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• v.4 no.4
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• pp.161-170
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• 1992

근래 들어 철근 콘크리트에 있어서의 철근부식이 관심의 대상이 되고 있는데 그이유는 이 현상이 실제 구조물에서 광범위하게 발생함이 확인되었고 이로 인한 보수비용이 급증하였기 때문이다. 철근의 부식이 처음 거론된 것은 해양구조물과 내화학성 구조물에서였고 최근 들어서는 교량상판, 주차공간등 염기에 노출되어 철근 부식이 우려되는 각 종의 구조물에 광범위하게 그 대책이 연구되기에 이르렀다. 이와같은 철근부식이 제어방법으로는 첫째로 콘크리트의 수밀화를 들 수 있고 다음으로 콘크리트의 표면을 처리하거나 피복두께를 늘이는 방법이 있다. 마지막으로 철근자체에 방청성능을 직접 부여하여 방법에 속하는 에폭시 도포 철근의 기본적인 방청성능을 고찰하기 위해 수행되었다. 연구결과 에폭시 도포철근의 방청성능은 매우 우수함을 발견하였고 앞으로 활용이 기대되고 있다.

• Journal of the Korea Computer Industry Society
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• v.9 no.4
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• pp.143-148
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• 2008

The major influence factor on carbonation of concrete structures is carbon dioxide concentration. In this study, carbonation analyses with carbon dioxide concentration were carried out by the developed program. Also, the service life of concrete strucures was predicted. The carbonation depth was 50mm in case that carbon dioxide concentration wad 0.1%. It was shown that the service life of concrete structures with 40mm cover depth was 67 years even though they had been exposed at carbon dioxide concentration 0.1% during 100 years.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.7-8
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• 2009

In this research, comparison and analysis were performed to understand how the cover thickness influences the equation for calculating the amount of confining reinforcement for reinforced concrete columns. And, also, an equation for calculating the amount of confining reinforcement was proposed for reasonable seismic design. In addition, appropriateness and safety of the proposed equation were examined based on the various experimental results performed at home and abroad.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.229-230
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• 2010

The Carbonation, one of the main deterioration factors of concrete, reduces capacity of members with providing rebar corrosion environment. Consequently it suggested standards of all countries of world, carbonation depth prediction equation of respective researchers and time to rebar corrosion initiation. As a result of carbonation depth prediction equation calculation, difference of time to rebar corrosion initiation is 149 years and difference of carbonation depth prediction equation is 162 years when water cement ratio is 50%. So a study on rebar corrosion with carbonation depth will need existing reliable data and verifications by experiment.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.641-646
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• 2000

This paper describes an experimental investigation on the influence of concrete cover thickness on tension stiffening behavior. Total 36 direct tension specimens were tested with variation of cover thickness. Three different concrete compressive strengths were also considered. After cracking, as the cover thickness becomes thinner and the concrete strength becomes higher, tensile stiffness is decreased. Thereby an increase in cover thickness results in increase of the tensile cracking load and tension stiffening effect. Also the increase in concrete strength results in sudden decrease in tension stiffening effect. Hence, the cover thickness and concrete strength are proved to be important factors in tension stiffening behavior.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.90-93
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• 2003

The most common deteriorating processes of concrete structures in the world-wide are carbonation and chloride ion. In this paper, chloride profiles of carbonated concrete is predicted to considering two layer composite model, which is based on Fick's 2nd law. From the experimental result on combined deterioration of chloride and carbonation, it was examined that high chloride concentration was built up to 3-5㎜ over depth from carbonation depth. The analytical modeling of chloride diffusion, which was based on the Fick's 2nd law of diffusion, was suggested to depict the relative influence of the carbonation depth.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.487-488
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• 2010

This is the experimental and analysis study on the thermal distribution, structural behavior and residual strength of high strength concrete members subjected to fire. The parameters are strength of concrete, cover thickness, loading state and exposure time to fire. The ISO 834 standard fire curve is used to test. The material and structural property of concrete at high temperature are proposed, also.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.143-144
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• 2010

As KCI under U.S.D is impossible to calculate all sections compared P-M Interaction Curve of the circular concrete column under EC2 of limit state design and KCI. Result of the construction, P-M Interaction Curve according to design for standard is about the same. If a covering depth rased, EC2 is better safety than KCI.