• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.53-56
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• 2006

To develop more durable concrete deck, performance characteristic test of HPC(High Performance Concrete) mixtures was carried out. The parameters used in this project were ; the mineral admixture details were 4 types such as ordinary portland cement(OPC), 20% fly ash (FA), 20% fly ash and 4% silica fume(FS), and 40% ground granulated blast-furnace slag(BS). Their design compressive strengths were 27MPa and 35MPa respectively. The results showed the compressive strength of concrete did not much affect the durability of concrete. HPC with blast-furnace slag(BS) showed the good durability but was prone to crack. HPC with fly ash(FA) or with fly ash and silica fume(FS) had the good durability and crack resistance.

• Computers and Concrete
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• 제12권6호
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• pp.831-850
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• 2013

The high strength materials have been more widely used in reinforced concrete structures because of the benefits of the mechanical and durable properties. Generally, it is known that the ductility decreases with an increase in the strength of the materials. In the design of a reinforced concrete beam, both the flexural strength and ductility need to be considered. Especially, when a reinforced concrete structure may be subjected an earthquake, the members need to have a sufficient ductility. So, each design code has specified to provide a consistent level of minimum flexural ductility in seismic design of concrete structures. Therefore, it is necessary to assess accurately the ductility of the beam sections with high strength materials in order to ensure the ductility requirement in design. In this study, the effects of concrete strength, yield strength of reinforcement steel and amount of reinforcement including compression reinforcement on the complete moment-curvature behavior and the curvature ductility factor of doubly reinforcement concrete beam sections have been evaluated and a newly prediction formula for curvature ductility factor of doubly RC beam sections has been developed considering the stress of compression reinforcement at ultimate state. Based on the numerical analysis results, the proposed predictions for the curvature ductility factor are verified by comparisons with other prediction formulas. The proposed formula offers fairly accurate and consistent predictions for curvature ductility factor of doubly reinforced concrete beam sections.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.47-52
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• 2003

This study was performed to investigate the flow behavior of fresh concrete. strength properties, and durability properties on the chloride penetration resistance of hardened concrete containing Meta-Kaolin(MK) in the range from common strength to high strength to facilitate the use. The results are compared with properties of concrete containing Si1ca Fume(SF). As a result. superplasticizer required in MK concrete was decreased by 8-28% compared to SF concrete with the same slump, but MK concrete became more sticky than SF concrete. It was also found that considering the strength, the optimal cement replacement ratio of MK was 15%, and MK had concrete durable and dense by decreasing the average pore diameter of concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.281-286
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• 1997

Recent construction activities and maintenance of marine facilities have been accelerating to keep up with rapid economic growth in Korea. Marine concrete structures are exposed to salts an chloride from ocean environments. The corrosion of reinforcement steel caused by chloride-penetration into concrete may severely effect the durability of concrete structures. The objective of this research is to develop a durable concrete by investigating the corrosion resistance of various corrosion protection systems utilizing different water/cement ratio, silica fumes, corrosion inhibitors and etc. A tow-year verification test on various corrosion protection systems has been doing in the laboratory and at the seaside. Corrosion investigations on reinforcement steel are now under progress for more than 180 concrete specimen. Corrosion-related measurements include macrocell corrosion current, instant-off voltage between corroding and noncorroding reinforcement, chloride contents, the corroded surface areas on the reinforcement steel, and etc. A low level of corrosion is investigated on reinforcement steels in concrete specimen made with corrosion inhibitors or applied aqueous impregnating corrosion inhibitors into their surface, even though high chloride contents of concrete specimen.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.821-824
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• 2004

For nuclear concrete structures on the coast, the prevention and management against salt damage is needed because they are being under the influence of the sea water at all times. In general, the deterioration of the concrete is generated in concrete surface firstly and then extended into concrete gradually as its service life increases. Therefore, the protective layer on the concrete surface is needed to establish and manage the durability of concrete. To enhance the durability performance of the existing and new concrete, the development and application of a high-performance penetration sealer is needed. The sealer has to have the functions that are able to prevent the attack of the moisture, carbon dioxide, and harmful substance from the outside. Therefore, the aim of this study is to development of a sealer for the long service-life and waterproof performance of a nuclear concrete structures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.897-900
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• 2006

This study concerned the quantification of environmental aggressiveness of concrete structure building up and applied to design of concrete structure. Only the content of carbon dioxide evacuated in the process of fabricating concrete structure was taken as an environmental load and various parameters, for example, material production, transportation, building-up, destruction and reuse were considered. Also, the life span of a concrete structure was taken into account in evaluating the carbon dioxide evolution. Consequently a single equation for the environmental load was obtained, which were subsequently used to assess the effect of high strength/durable concrete structures.

• 한국도로학회논문집
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• 제15권5호
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• pp.101-110
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• 2013

PURPOSES : The purpose of this study is to evaluate the durability of ternary blended concrete mixtures adding ultra fine admixture. METHODS : From the literature review, crack was considered as the main distress failure criterion on concrete bridge deck pavement. To reduce the initial crack development due to drying shrinkage, CSA expansion agent and shrink reduction agent were used to ternary blended concrete mixtures as a admixture. Laboratory tests including chloride ion penetration test, surface scaling test, rapid freeze & thaw resistance test, non restrained drying shrinkage and restrained drying shrinkage test were conducted to verify the durability of ternary blended concrete mixtures. RESULTS : Based on the test results, proposed mixtures were verified as high qualified durable materials. Expecially initial drying shrinkage crack was not occurred in ternary blended concrete mixtures with CSA expansion agent. CONCLUSIONS : It is concluded that the durability of proposed ternary blend concrete mixture was acceptable to apply for the concrete bridge deck pavement.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.123-124
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• 2009

이 연구는 단부거더(Edge girder) 형식의 하이브리드 사장교 적용을 목적으로 하는 최적의 초고성능콘크리트(Uitra High Performance Concrete) 프리캐스트 바닥판 시스템 개발의 일부이다. 고성능 재료인 UHPC의 성능을 적극적으로 활용할 수 있는 고효율 구조형식으로서 교축방향으로 프리스트레스가 도입된 리브를 가지는 단면형식이 제안되었고, 최소요구단면 도출을 위한 설계개념을 정립하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.265-271
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• 1997

Marine concrete structures have been exposed to salt from ocean environments. Chloride-penetration into marine concrete structures should accelerate the corrosion of reinforcement steel, which may severely affect the durability of them. Major concerns are to develop durable concrete for high corrosion resistance of reinforcing steel embedded in concrete. The objective of this experimental study is to investigate adequate usage of corrosion inhibitors by evaluating corrosion level in 80 specimen located in the labatory and in the site. 80 specimen of cube 20${\times}$20${\times}$11.5 and 63 specimen of slab 30${\times}$30${\times}$10 are made for this study.

• Steel and Composite Structures
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• 제22권2호
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• pp.387-398
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• 2016

In order to evaluate the effects of U shape ultra high performance concrete (UHPC) permanent form on the behaviors of Reinforced Concrete (RC) beam, a full scale RC composite beam is designed and tested with U shape UHPC permanent form and a reference RC beam with same parameters is tested simultaneously for comparison. The effects of the permanent form on the failure mode, cracking strength, ultimate capacity and deformation are studied. Test results shows that the contributions of the U shape UHPC permanent form to the flexural cracking behaviors of RC beam are significant. This study may provide a reference for the design of sustainable RC beam with high durable UHPC permanent form.