• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.45-46
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• 2016

As the demand for super tall buildings is currently increased in domestic and foreign countries, some kinds of ultra-high strength concretes are being developed actively. Since the cross section of concrete becomes smaller thanks to such kinds of ultra-high strength concretes, the concrete structures can be much bigger, more gigantic and much ultra-high. And as another benefit which is generated thanks to the enhancement of the durability performance, the maintenance expenses are also saved. However, since low W/B ultra-high concrete has a high possibility that many cracks can occur in the initial period due to the self-shrinkage caused by the self-desiccation as one of the blending characteristics, the problem becomes bigger by influencing the safety of a structure. Therefore, in this study, it is intended to analyze the effects of substituting some limestone-based ultra-high strength mortar with electric arc furnace oxidizing slag fine aggregates on the self-shrinkage of mortar.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.9-14
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• 1998

In this paper, we described the basic elements(flowabiligy, fillingability, elapsed time, pumpability, no-vibrating effects, and etc.) required for the application and quality control of the super flowing concrete(SFC) in Top Down site. Also, manufactured sand and fly ash were used for investigating characteristics of SFC through various experiments(mix design, optimum mix condition) before placing the concrete in site. As a result of this project, the developed SFC shown high flowability and self-fillingability in the joint good enough for the requirement. Futhermore, inner uniformity of the no-vibrated concrete was verified by testing reformed space. Therefore, quality control and compressive strength(360kg/$\textrm{cm}^2$) can be secured by using SFC even without vibrating.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.916-921
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• 1998

This study describes the result for the placement of the super flowing concrete(SFC) in under-pinning-top-slab which is located Inchon subway section 1-10 where, due to heavy reinforcements and limited working space, it was difficult to place concrete. After placing 600㎥, smooth construction and quality control were possible due to the good flow-ability, self-fillingability, and the resistance of segregation of the SFC itself. Furthermore, economical efficiency was obtained through not only the reduction of the works, labors, and site noise but also the efficient construction control. Because of the crack prevention, high strength, and a fine concrete surface, this study could be considered as a momentum to be adopted generally for applying the proposed method to the difficult subway construction area in the near future.

• 한국재난정보학회 논문집
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• 제13권4호
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• pp.455-464
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• 2017

I형 강거더의 압축부에 SUPER(Sustainable Ultra performing, Pioneering, Economic, Remarkable) Concrete가 합성된 거더의 휨거동 특성을 평가하기 위해 정적재하시험을 수행하였다. 실험체는 총길이 25m, 형고 786mm이고 압축부 콘크리트(이하 케이싱) 강도는 80MPa이며 4점 재하로 하중 2,010kN까지 가력하여 휨거동을 분석하였다. 실험 결과 사용 하중의 2.7배에서 인장 플랜지가 항복하였고 연성비는 1.481였다. 실험 종료까지 케이싱 균열은 확인되지 않았으며 단면 간 상대변위량은 미미한 수준임을 확인하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.651-654
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• 2005

Fast-setting cement is usually used for emergency repair construction of roads, bridges, buildings and so on. In this study, we tried to develop fast-setting ultra early strength mortar for prepacked concrete and evaluated the properties of fresh and hardened concrete with it. The flowability of the mortar was high enough to be easily poured into coarse aggregates. It showed high early strength development which can make it possible to use newly constructed structures within $3\~4$ hours regardless of curing conditions such as curing temperature and curing environment. And it also showed good resistance to drying shrinkage and chemical attack.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.44-45
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• 2014

On this study, initial crack index was evaluated by performing FEM analysis to crack propagation from hydration heat for development of precast concrete. On the result, as increased the usage of hardening accelerator, initial compressive strength were improved and setting time also was shortened. Additionally, central temperature of concrete was increased, the reaching time for the highest temperature could be shortened. By the result to assess crack index, there was no problem about crack despite of growth of initial high hydration heating. This result guessed because of small size element when analyzed trough FEM, realization for mass concrete's crack index should be performed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.33-36
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• 2006

In manufacturing Ultra high strength fiber reinforced concrete(UHSFRC), steel fiber, super-plasticizer and silica fume are important but they are imported materials therefore very expensive. consequently it is necessary to find substitutes of them or to develop producing techniques in order to manufacture UHSFRC economically. In this study, we investigated if it was possible to substitute blast-furnace slag instead of silica fume and steel fiber of home manufacture instead of one of overseas manufacture.

• 국제초고층학회논문집
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• 제11권1호
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• pp.61-68
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• 2022

The Address Jumeirah Resort is a mixed-use 77-story tower reaching a height of 301 meters with a slenderness ratio of 13.5:1. The development is situated in the Jumeirah Beach District and accommodates 217 key five-star hotel suites, 478 residential apartments, 444 serviced-branded apartments, retail shops, ballrooms and entertainment facilities around the premises. The building has over 242,000 m2 of usable area. The project is an award-winning development that broke multiple Guinness records. The focus of the paper is to present the challenges faced in the structural design and construction of the super tall tower and the highest occupiable skybridge in the world.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.37-40
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• 2007

This study investigates the effect of the pre-mix cement to the physical properties of the concrete according to the various combinations of the binders and the silica fume types. The results are summarized as following. For the properties of the fresh, the fluidity in the case that OPC+cilica fume-blast-furnace slag is appropriate compared to OPC+cilica fume+fly ash. Expecially, it is favorable when pre-mix is used. The fluidity time of the A, B depending on silica fume types is favorable, but it is decreased on C. The air content depending on silica fume types is low when the fly ash is used. Specially, the air content in the case that pre-mix is used is low caused by the dispersion of the silica fume. For the properties of the hardened concrete, the compressive and flexible strength when the blast-furnace slag is pre-mixed are high, and they exceed OPC. The strength depending on the silica fume types is high on B, and the strength of the others is similar.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.149-150
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• 2023

This study proposes the most suitable strength prediction model equation for UHPC by calculating the apparent activation energy of UHPC according to the curing temperature and deriving the integrated temperature and compressive strength prediction equation. The results are summarized as follows. The apparent activation energy was calculated using the Arrhenius function, which was calculated as 21.09 KJ/mol. A model equation suitable for UHPC was calculated, and when the Flowman model equation was used, it was confirmed that it was suitable for the properties of UHPC using a condensation promoting super plasticizing agent.