• 한국건축시공학회지
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• 제14권3호
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• pp.273-284
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• 2014

Ultra-high-performance concrete (UHPC) consists of cement, silica fume (SF), sand, fibers, water and superplasticizer. Typical water/binder ratios are 0.15 to 0.20 with 20 to 30% silica fume. In the production of ultra-high performance concrete, a significant temperature rise at an early age can be observed because of the higher cement content per unit mass of concrete. In this paper, by considering the production of calcium hydroxide in cement hydration and its consumption in the pozzolanic reaction, a numerical model is proposed to simulate the hydration of ultra-high performance concrete. The heat evolution rate of UHPC is determined from the contributions of cement hydration and the pozzolanic reaction. Furthermore, by combining a blended-cement hydration model with the finite-element method, the temperature history in the hardening of UHPC is evaluated using the degree of hydration of the cement and the silica fume. The predicted temperature-history curves were compared with experimental data, and a good correlation was found.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.107-111
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• 2008

As high-rise buildings with 100 or more stories are being constructed, it is inevitable to use high-performance materials including high-performance concrete. What is most important in high-performance concrete is extremely high strength in order to reduce the section of members in high-rise buildings. During the last several years, there have been active researches on Ultra-high-strength concrete. While these researches have been mostly focused on strength development, however, other accompanying physical properties have not been studied sufficiently. Thus, this study purposed to obtain and analyze data on the physical-mechanical properties of Ultra-high-strength concrete through experiments and to use the results as basic information on required performance of concrete used in high-rise buildings.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.549-552
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• 2006

Generally the ultra-high strength steel reinforced concrete has rich mix composition composed of high-strength type mineral admixtures and as a result of very low water-binder ratio(about under w/b=25%), it reveals ultra-high compressive strength(about over 100Mpa). Also, in order to obtain sufficient toughness after construction, we usually mix a large quantity steel fiber with ultra-high strength steel reinforced concrete therefore we must use proper mixer for workability. When we make the ultra-high strength steel reinforced concrete we need more long mixing time or much super-plasticizer than when we manufacture normal concrete. These bring about economical problems and performance deterioration. Therefore, in this study, in order to manufacture easily ultra-high strength steel reinforced concrete we develope a dedicated mixer for ultra-high strength steel reinforced concrete with high speed type. It carried out the examination for comparison between the dedicated and general type mixer, the analysis and counterplan of the point at issue when we manufacture ultra-high strength steel reinforced concrete by the dedicated mixer.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.94-95
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• 2020

This paper introduces the mix design and performance evaluation of Ultra-High Performance Concrete (UHPC). The concrete mixture is designed to achieve a densely compacted cementitious matrix via the modified Andreasen & Andersen particle packing model. The compressive strengths of UHPC designed by this method reached 154MPa. The relationship between packing theory and compressive strength of UHPC is discussed in this paper.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.61-64
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• 2009

Recently, the higher buildings are, the stronger concrete are used. Ultra high strength concrete have the possibility of spalling when a fire breaks out. so the fire-resistance performance is necessary to use the ultra high strength concrete on the high-rise building. On this study, the heating test for the concrete with loading/unloading is performed for ultra high strength concrete using nylon fiber. The heating test followed by ISO-834 heating curve on the real-size specimen and the strength of concrete are 60, 80, 100, 200 MPa.

• 한국건설순환자원학회논문집
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• 제8권3호
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• pp.269-275
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• 2020

본 연구에서는 초고성능 콘크리트를 적용한 경량 프리캐스트 패널 개발의 일환으로 단면 두께와 철근 배근 유무에 따른 패널의 휨 재하 실험을 수행하였다. 일반 콘크리트 패널 1개와 초고성능 콘크리트를 사용한 경량 프리캐스트 패널 3개로서 총 4개의 패널을 제작하였다. 초고성능 콘크리트를 사용하고 철근을 보강하지 않은 패널은 단면 크기와 상관없이 일반 콘크리트 패널에 비해 휨 성능이 저하되는 것으로 나타났다. 초고성능 콘크리트를 적용한 속빈 단면에 콘크리트 양을 감소시킨 패널은 일반 콘크리트 패널에 비해 휨 성능이 150% 향상되었다. 이는 초고성능 콘크리트를 사용한 프리캐스트 패널의 단면 최적화 설계를 통해 더욱 경량화가 가능할 것으로 판단된다. 초고성능 콘크리트를 사용한 경량 프리캐스트 패널을 실제 구조물에 적용하기 위해서는 전단 성능과 연결 상세에 대한 추가 검토가 필요할 것으로 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.1-4
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• 2007

Because reinforced concrete structures were being high more and more in recent year, concrete was being demanded high performance of high strength and high fluidity. But various characteristics must be confirmed besides guarantee of demand strength in ultra-high strength concrete. In ultra-high strength concrete, autogenous shrinkage and drying shrinkage grow big because of a low water cement ratio and much quantity of binder. So dangerousness of crack generation grow big in early ages. And ultra-high strength concrete is influenced by use materials more than ordinary strength concrete. In this study we were examined mix design, atuogenous shrinkage and pumpability of ultra-high strength concrete to apply on the ground.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.286-287
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• 2014

Performance degradation of Ultra High Strength Concrete occurs more than that of normal strength concrete at high temperature. Thus, strain of concrete subjected to high temperature and loading is one of the core assessment items for evaluating performance of structures. Therefore, in this study, creep of ultra high strength concrete subjected to various temperature conditions and 25%, 40% loading was evaluated. As the results, Creep strain increased with increase of temperature and loading. Creep strain of concrete at high temperature is influenced by loading.

• International Journal of Concrete Structures and Materials
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• 제10권2호
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• pp.125-142
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• 2016

An overall review of the structural behaviors of ultra-high-performance fiber-reinforced concrete (UHPFRC) elements subjected to various loading conditions needs to be conducted to prevent duplicate research and to promote its practical applications. Thus, in this study, the behavior of various UHPFRC structures under different loading conditions, such as flexure, shear, torsion, and high-rate loads (impacts and blasts), were synthetically reviewed. In addition, the bond performance between UHPFRC and reinforcements, which is fundamental information for the structural performance of reinforced concrete structures, was investigated. The most widely used international recommendations for structural design with UHPFRC throughout the world (AFGC-SETRA and JSCE) were specifically introduced in terms of material models and flexural and shear design. Lastly, examples of practical applications of UHPFRC for both architectural and civil structures were examined.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.55-56
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• 2014

In this research, the effect of types of aggregate and SP on fundamental properties of ultra-high performance concrete of 80 MPa of compressive strength was evaluated to provide solution for high cost of ultra-high performance concrete. As the results of a series of tests, the mixture using limestone and silica aggregates showed improved workability rather than the mixture using granite aggregate. For compressive strength of UHPC, the UHPC mixtures using limestone and silica aggregates showed higher compressive strength than the UHPC mixture using granite aggregate while all mixtures satisfied target compressive range.