• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.61-64
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• 1997

As construction technology advances, most of concrete structures are becoming larger and taller. Therefore, high strength and quality concrete is necessary for them. So, the proposal of using belite cement is investigated to satisfy high flowing, low heat, and high strength. In this study, the compressive strength, tensile strength, and modulous of elasticity of concrete using belite cement was considered according to the mix proposition condition as a water-cement ratio, unit cement content, and sand percentage.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.449-452
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• 2008

본 연구는 골재의 표면수 변동에 따른 콘크리트의 품질변동이 안정하며 현장에서 무진동 무다짐 시공이 가능한 병용계 고유동 자기충전콘크리트 (High flowing Self-Compacting Concrete ; 이하 HSCC라 약함)를 제조하였으며, 실내실험을 통하여 경화 전 후 콘크리트에서 발생하는 기포의 저감 요인을 검토하고자 한다. 병용계 HSCC는 굳지 않은 콘크리트의 점성을 증가하기 위하여 증점제의 사용은 필연적이며 이러한 결과 분체계 HSCC보다 많은 수의 기포를 발생시킨다. 또한 경화 후 콘크리트 내에 갇흰공기의 발생으로 만들어진 표면의 기포는 구조물의 미관뿐만 아니라 강도 및 내구성에도 나쁜 영향을 미치는 연구결과가 보고 되고 있다. 본 논문에서는 병용계 HSCC의 기포발생을 저감하기 위하여 골재(잔골재) 종류, 콘크리트 비빔시간, 박리제 종류 및 모형 거푸집 재질에 따른 콘크리트의 기포발생에 대한 실험을 실시하였다. 실험 결과 박리제 및 모형 거푸집 재질에 따른 경화 후 병용계 HSCC의 표면마감성능은 거푸집의 영향 보다 박리재의 영향이 크게 작용하였으며 불투명 구리스가 가장 좋은 마감상태를 유지하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.247-248
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• 2009

고유동 콘크리트는 국내 외 시험성능 규정을 통하여 고유동 콘크리트의 슬럼프 플로 및 500mm 도달시간에 대한 실험 방법이 제시되었다. 하지만 고유동 콘크리트의 유동성능 측정 방법인 슬럼프 플로 시험방법은 사람 개개인 마다 인식 하는 능력이 상이함에 따라 오차가 발생한다. 본 연구에서는 이러한 실험방법에 대한 오차를 보다 정밀화하기 위하여 레이져 다이오드를 통한 실험값의 오차를 없애고자 한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.401-404
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• 2006

This study is the part of the investigation of the state of the art in ultra high flowing concrete (UHFC), applied in practical field construction, in order to develop the technology for improving workability. This paper includes a brief introduction of water content variance properties in UHFC before and after the pumping operation. Test showed that water content in all parameters decreased after the pumping. This is due to the increase of an absorption ratio of coarse aggregate by the pressure of the pumping operation. thus decreasing the water content. Therefore it should be considered to find out the possibility, which can improve the workability, suffering from over viscosity by the lower water content, in field construction.

• International Journal of Concrete Structures and Materials
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• 제2권2호
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• pp.145-152
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• 2008

So far, there has been no study of the concrete to strengthen in the lining of the tunnels, except for the study of the stability of subgrade and the tunnel construction technologies. In the existing concrete work for tunnel lining, lots of problems happen due to the partial compaction and the material segregation after casting concrete. Accordingly, the aim of this study is to improve economic efficiency and secure durability through the improvement of the construction performance and quality of the concrete for the tunnel lining among the civil structures. Therefore, the compactability and strength properties of the High Flowing Self-Compacting Lining Concrete (HSLC) are evaluated to develop the mixing proportion for design construction technology of HSLC that can overcome the inner cavity due to the reduced flowability and unfilled packing, which has been reported as the problem in the existing lining concrete. The result of the evaluation shows that the ternary mix meets the regulations better than the binary mix. Consequently, it has been judged applicable to the cement for tunnel lining.

• 대한토목학회논문집
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• 제29권5A호
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• pp.511-518
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• 2009

본 연구에서는 콘크리트와 철근과의 부착강도에 영향을 미치는 요인 중 철근의 위치를 수평하부철근(Horizontal reinforcement at Bottom position, HB), 수평상부철근(Horizontal reinforcement at Top position, HT), 및 수직철근(Vertical reinforcement type, V)으로 변화시킨 시험체를 제작하여 3수준의 콘크리트 강도 변화(30, 50 및 70 MPa)에 따른 고유동 자기충전 콘크리트(High flowing Self-compacting Concrete, HSCC) 및 일반콘크리트(Conventional Concrete, CC)와 이형철근의 부착 특성을 비교 분석 하였다. HSCC 및 CC의 상부근 철근계수를 평가하기 위하여 HB/HT 철근의 부착강도비를 측정한 결과 50 및 70 MPa의 경우 HB/HT의 부착강도비는 1.3이하로 나타났으며, 30 MPa의 경우 HSCC 및 CC에서 각각 1.2 및 2.1로 나타났다. 따라서 HSCC 30, 50 및 70 MPa의 경우 콘크리트구조설계기준(2007) 정착길이 설계시 상부근 계수에 제시되는 수평상부철근에 대한 정착길이 보정계수를 CC의 1.3보다는 감소시켜 적용하는 것이 바람직할 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.463-468
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• 1999

The slurry wall of Inchon LNG receiving terminal tank will be planned the super flowing concrete having properties of high strength (required strength 520kg/$\textrm{cm}^2$), no-vibrating and massive structure in the underground. For the performance of this concrete, we investigate and select all materials, the optimum mix design and sensibility test in the laboratory. As test results, we choose portland blast-furnace slag cement and lime stone powder(L.S.P) as cementitious materials, W/C 41%(W/B 35.4%), S/a 50.8% and unit volume of coasre aggregate 0.30 as optimum mix design. Also test result of the fresh and hardened concrete are satisfied with specifications of slurry wall.

• 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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.489-492
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• 2006

Needs for the new technologies and cutting-edge Ultra Flowing Self-Compacting Concrete are emerging as the concrete structures are becoming bigger and more specialized recently. In North America and Europe, SCC, which has high resistance against flow ability and segregation, is being used as concrete material in applications such as precast and prestressed bridges, where reinforcing bars are overcrowdedly placed. In Korea, SCC has been utilized limitedly in building structures but its utilization should be expanded to engineering structures such as bridges. In this study, for the application in precast and prestressed bridges with overlycrowded reinforcing bars, USCC was mixed with admixtures to give a binary system and a ternary system according to the 1st grade rules by JSCE (Japan Society of Civil Engineers). Compressive strength and splitting tensile strength of the resulting USCCs were tested. Elastic modulus were compared with the values suggested in CEB-FIP code and ACI 318-05.