• Title/Summary/Keyword: 고유동콘크리트

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Development and Utilization of High Fluidity Concrete (고유동 콘크리트의 개발 및 활용)

  • Choi, Yun-Wang;Jeong, Jae-Gwon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.1109-1112
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    • 2008
  • Concrete structure is recognized as the universal structuring material for its outstanding formability, economic efficiency, and strength development. However, as the ageing of field workers and the deficiency of skilled workers due to evasions from 3D business have recently become the major issues of the industry in Korea and as the materials are becoming more diversified and complicated for today's concrete structures are becoming higher, larger, and specialized, the need for practicality of construction work based on new technology and new method has greatly increased. Therefore, the overall condition of today's construction business requires researches and developments on the high fluidity concrete for higher construction efficiency and quality improvements. With this reason, this study investigated study development tendency and development situation of the high fluidity concrete, arranged experiment performance, and domestic or international specification used in performance valuation of the high fluidity concrete.

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Cracking Characteristics of RC Beams made of High Flowing Self-Compacting Concrete (고유동 자기충전 철근 콘크리트 보의 균열특성)

  • Ahn, Tae-Ho;Kim, Jin-Cheol;Kim, Hong-Sam;Ha, Sung-Kug;Lee, Haeng-Ki;Choi, Yun-Wang
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.425-426
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    • 2010
  • The cracking characteristics of high flowing self-compacting concrete(HSCC) and conventional concrete(CC) was investigated. HSCC shows high crack resistance compare to CC due to self compacting properites.

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Development Trend and Present Situation of High-Performance Concrete in Japen (일본의 고유동 콘크리트 개발 및 사용현황)

  • 김은겸;최재진;전찬기;이호석
    • Magazine of the Korea Concrete Institute
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    • v.14 no.4
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    • pp.66-71
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    • 2002
  • 고유동 콘크리트는 높은 변형성과 분리 저항성에 의해 자기충전성을 갖는 콘크리트로서 외부에서 힘을 전혀 가하지 않거나 또는 아주 작은 힘만으로 재료분리 없이 거푸집 구석구석까지 충전되는 특징을 가진다. 이러한 고유동 콘크리트는 일본 동경대학의 강촌 보 교수에 의해 제창되었는데 콘크리트의 다짐을 하지 않아도 된다면 시공방법의 영향을 받지 않고 신뢰성이 높은 구조물을 만들 수 있을 뿐 아니라 1회치기 높이의 제한, 다짐작업을 위한 발판, 박스단면에서 밑면과 벽체 부분의 분할치기 등의 제약을 받지 않게 되고, 강 콘크리트 샌드위치 합성구조 등의 새로운 구조형식도 용이하게 시공할 수 있어 많은 이점을 가질 수 있다.(중략)

Properties of Hydration Heat with Compressive Strength Level of High Flowing Self-Compacting Concrete (고유동 자기충전 콘크리트의 압축강도 수준에 따른 수화발열 특성)

  • Choi, Yun Wang;Jung, Jea Gwone;Lee, Jae Nam;Kim, Byoung Kwon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.5A
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    • pp.531-541
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    • 2009
  • The research analyzes and investigates conventional concrete, hydration heat, set, and mechanical properties by making high flowing self-compacting concretes of binary blend and ternary blend as one of evaluations about the properties of the hydration heat of high flowing self-compacting concrete with a strength of 30, 50, and 70 MPa. In addition, it estimates concrete adiabatic temperatures by calculating a thermal property value of powder obtained by measuring a heat evolution amount for powder used in concrete, a thermal property value of concrete obtained by conducting a simple adiabatic temperature test, and a normal thermal property value of material used in concrete, using a simple equation. Moreover, it analyzes and investigates the hydration heat property of high flowing self-compacting concrete and the thermal stress caused by hydration heat by conducting a 3D temperature stress analysis for the hydration heat and the adiabatic temperature obtained by temperature analysis, using MIDAS CIVIL 06 program.

Determination of Optimal Mixture Proportion of Segregation Reducing Type Superplasticizer for High Fluidity Concrete (고유동 콘크리트용 분리저감형 유동화제의 최적배합비 결정)

  • 한천구;김성수;손성운
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.275-282
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    • 2002
  • High fluidity concrete needs high dosage of superplasticizer to acquire sufficient fluidity and high contents of fine powder and viscosity agents to prevent segregation. But it requires high manufacturing cost and has difficult in quality control. Therefore, in this paper, determination of optimal mixture proportion of segregation type superplasticizer for high fluidity concrete and manufacturing high fluidity concrete by applying developed segregation reducing type superplasticizer are discussed using flowing concrete method. According to test results, as dosage of superplasticizer increases, it shows that fluidity and bleeding increase, while air contents and ratio of segregation resistance decrease. It also shows that adding viscosity agent into it reduce bleeding and improve segregation resistance. Dosage of AE agent into it containing viscosity agent recovers loss of air contents during flowing procedure. Combination of proper contents of superplasticizer, viscosity agent and AE agent make possible to develope segregation reducing type superplasticizer Compressive strength of high fluidity concrete applying flowing method with it is higher than that of base concrete. No differences of compressive strength between compacting methods are found.

The Rheology of Cement Paste Using Polycarboxylate-Based Superplasticizer for Normal Strength-High Fluidity Concrete (보통강도 고유동 콘크리트용 PC계 고성능 감수제를 사용한 시멘트 페이스트의 레올로지 특성 평가)

  • Kong, Tae-Woong;Lee, Han-Seung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.3
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    • pp.276-286
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    • 2021
  • General high fluidity concrete is the area of high strength concrete with a high amount of cement to secure the required fluidity and workability. Since most of the concrete structures currently used have normal strength, there is a limit to the practical expansion and practicality of use. Thus it is necessary to develop normal strength-high fluidity concrete with low binders that can be used not only in general buildings but also in special buildings, and can greatly reduce construction time and save labor costs. This requires to develop and apply the polycarboxylate-based superplasticizer. In this study, PCE was prepared for each combination of starting materials(WR, HB, RT) and the rheological properties of cement paste were analyzed using ringflow cone and a rotary viscometer. As a result, when PCE with a combination of WR 80%, HB 6.5%, and RT 13.5% was applied, the yield stress can be minimized while securing the plastic viscosity at level of the normal strength. In addition, high fluidity due to the high dispersion effect was confirmed.

Chloride Ion Penetration Properties of Normal Strength High-Fluidity Concrete Using Lime Stone Powder (석회석 미분말을 활용한 보통강도 고유동 콘크리트의 염소이온 침투특성)

  • Choi, Yun-Wang;Moon, Jae-Heum;Eom, Joo-Han
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.4
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    • pp.160-168
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    • 2010
  • Recently, there are a lot of researches related to the high-fluidity concrete (HFC) with field applications. However, most applications and studies are with concretes with high strength level so there are little studies about durability evaluations such as chloride ion penetration properties with normal strength concrete. Therefore, to evaluate the durability of HFC with normal strength level, this study performed the chloride ion penetration test and observed the micro pore distribution with normal strength HFC which contains limestone powder. Experimental results showed that most micro-pores have diameters between 0.005 to 0.05 ${\mu}m$ with HFCs using limestone powder and the average diameter becomes larger with the increase of limestone powder content. Also, it was shown that, with the increase of the limestone powder content, penetration depth and diffusion coefficient of chloride ion increased and diffusion coefficient had good relationships with compressive strength and average pore diameter with the coefficient of determination over 0.90.