• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회논문집(II)
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• pp.653-660
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• 1998

Bond strength of reinforcing bar to high-performance concrete using belite cement is explored using beam end test specimen. The key parameters for the bond test are slump of concrete, top bar effect, and strength of concrete in addition to concrete covers. Specimen failed in the typical brittle bond failure splitting the concrete cover as the wedging action. The test results show that the specimens with belire cement concrete show higher bond strength than those with portland cement concrete. Bond strength of the top bar is less than bond strength of bottom bar, but the top bar factor satisfies the modification factor for top reinforcement. The results also show that the bond strength is function of the square root of concrete compressive strength and cover thickness. The recently developed high-strength and high-slump concrete with belite cement performs well in terms of bond strength to reinforcing steel.

• 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 1998년도 가을 학술발표논문집(II)
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• pp.501-506
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• 1998

This paper is an experimental study on the flexural strength and ductility capacity of reinforced high performance concrete beams with the concrete which has compressive strength of 600~700kg/$\textrm{cm}^2$, slump value of 20~25cm and slump-flow value of 60~70cm. Total 8 beams with different tensile reinforcement ratio and pattern of loading were tested. Form the results of reinforced high performance concrete beams, the equivalent stress block parameters proposed by MacGregor et al. or New Zealand code are recommended to use. Also, an extreme fiber concrete compressive strain of reinforced high performance concrete beams are distributed 0.0033~0.0048. In reinforced high performance concrete beams, reinforcement ratio in order to insure curvature ductility index 2 and 4 propose by ACI code should be less than those of reinforced normal strength concrete beams.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.290-294
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• 1996

High-Belite cement had a better slump flow characteristics than type I cement and slag cement, and its varation of slump flow with time was also excellent. As the amount binder added was increased, the strength increased while material separation decreased. This phenomena was obvious when the amount of cement was abobe 500kg/$\textrm{m}^3$ . When the amount of cement and S/a were 516kg/$\textrm{m}^3$ and 52% respectively, the application strength of 600kg/$\textrm{m}^3$ was satisfied. Since, however, the aggreate size of 25mm was somewhat unsatisfactory, the characteristics of high performance concrete could be obtained by the addition of the viscosity-enhancing agent.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.205-208
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• 2002

This study is performed to examine the flowability and filling ability of steel fiber reinforced high performance concrete. For the estimation of the flowability and filling ability, slump flow, box height difference and L-shape filling appearence are measured and compared. The test result shows that the slump flow is $60{\pm}5cm$ to make no difference with containing steel fiber, box height difference is increased with increasing steel fiber and L-shape filling appearence is to bad with increasing steel fiber. But, proper containg of steel fiber is considered to be applied for high performance concrete without decreasing of slump flow and filling ability.

• 한국방재학회 논문집
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• 제11권1호
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• pp.1-6
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• 2011

고강도 콘크리트의 폭렬현상을 억제하여 내화 성능을 개선하기 위한 방법으로 고온에서 수증기가 콘크리트 표면으로 이동할 수 있도록 경로를 제공하여 주는 섬유를 혼입하는 방안이 있다. 섬유를 혼입하여 콘크리트의 폭렬을 억제하는 방법은 고온에 의해 콘크리트 내부에서 용융되는 섬유에 의해 만들어지는 통로가 서로 연결되어 고압의 수증기를 콘크리트 외부로 이동시킬 수 있을 때 효과가 있다. 수증기가 배출될 통로를 형성하는 섬유의 연결성에 대한 percolation 이론을 섬유혼입 고강도 콘크리트의 내화실험 결과에 적용하였다. 본 연구에서는 percolation 이론과 섬유혼입 고강도 콘크리트의 폭렬 발생의 연관성을 분석하였고, 섬유혼입 고강도 콘크리트 가상 시편을 이용하여 내부 섬유 입자가 서로 연결되어 있는 것을 입체적으로 구현하고 일정 부피비의 섬유가 혼입되었을 때 수증기 배출 통로가 확보되는 것을 확인하였다.

• 한국산학기술학회논문지
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• 제16권12호
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• pp.8363-8369
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• 2015

본 연구에서는 고유동 콘크리트에서 일라이트 미분말을 대체한 콘크리트의 유동성과 충전성 및 압축강도 특성을 조사하기 위한 것이다. 이러한 목적으로 일라이트 미분말을 고유동 콘크리트에 5, 10, 15, 20%를 대체한 후 치환율에 따른 콘크리트의 특성을 알아보았다. 콘크리트 배합 후 굳지않은 콘크리트에서 슬럼프 플로우 시험, 500mm플로우 도달시간 및 O-lot 시험을 실시하였으며, 굳은 콘크리트의 특성으로 재령 28일에 고유동 콘크리트의 압축강도를 측정하였다. 시험결과 고유동 콘크리트의 유동성 및 충전 높이는 일라이트 미분말 10%를 대체하였을 때까지 증가하는 것으로 나타났다. 그리고 고유동 콘크리트의 압축강도 특성을 살펴본 결과에서도 일라이트 미분말 10%를 대체하였을 때까지 강도증진이 발생하였다. 따라서 본 실험결과 일라이트 미분말의 혼입율이 10%일 때 최적 치환율이 되었음을 확인할 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.19-24
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• 1995

Most difficulties in inducing high flowability of general strength concrete arise from the segregation of aggregates due to the shortage of cementatious binders. To solve the problem, our research team has concentrated on finding the binders to link a gap between coarse and fine aggregates, under the condition not to influence a concrete strength. As a result of using stone powder or a middle class of aggregate size mostly used for asphalt pavement(Max. dia 13mm), we found that flowability of concrete increased significantly without aggregation and decrease of compressive strength.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2002년도 학술.기술논문발표회
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• pp.99-102
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• 2002

This paper discusses the estimation of construction cost of high fluidity concrete using segregation reducing type superplasicizer with 350kgf/cm2 of design strength and 60$\pm$5cm of slump flow in order to verify the cost down effect of high fluidity concrete compared with that of plain concrete with 350kgf/cm2 of design strength and 18cm of slump and with 210kgf/cm2 of design strength and 15cm of slump. According to research, under same strength levels, although material cost of high fluidity concrete is somewhat higher than that of plain concrete due to segregation reducing type superplasticizer, labor cost and equipment cost of high fluidity concrete is cheaper than that of plain concrete. However, based on the strength differences, high fluidity concrete shows lower material cost, labor cost and equipment cost than that of plain concrete due to decreasing in size of member and re-bar caused by high strength development of concrete.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1244-1248
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• 2007

This study aims at investigating the in situ applying grass concrete system in river environments which widely used nowadays and reviewing the effect and flow resistance for grass concrete structure through the physical experiments by hydraulic model test and developing application method in river bed which has rigid flood resistance. Grass concrete structure has been independently tested under high velocity flow under the super critical condition, as well as sud critical flow measuring velocity and water surface elevation along the cross section. This results shows grass concrete system is also suited to use in aggressive river environments such as repairing a flood damaged embankment that had placed at risk the adjacent drainage channel with vegetation.