• 제목/요약/키워드: High Fluid Concrete

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고로슬래그미분말을 혼입한 고유동콘크리트에서 골재조합이 콘크리트 유동성상에 미치는 영향에 관한 실험 연구 (The Effect of Combined Aggregates on Fluidity of the High Fluid Concrete Containing GGBFS)

  • 김재훈;윤상천;지남용
    • 한국건축시공학회지
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    • 제3권4호
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    • pp.79-86
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    • 2003
  • The purpose of study is to offer base data for high fluid concrete mix property, as grasp effect of aggregate to reach much more effect for producing high fluid concrete. For this study, there are three types of combined aggregates, river sand + river aggregate(type A), river sand + crusted aggregate(type B), washed sea sand + crushed aggregate(type C) and take a factor, water-contents, water-binder ratio and S/a. And so, we had following conclusion, resulting application-ability of high fluid mortar by K-slump tester to use a handy consistency measuring instrument. And so, we had following conclusion, resulting application-ability of high fluid concrete by K-slump tester to use a handy consistency measuring instrument. 1) In cafe of regular water binder ratio, high fluid concrete suffered much effect of combined aggregates and water binder ratio. Range of water binder ratio by combined aggregates is w/b 0.4 downward(type A and B), w/b 0.35 downward(type C). 2) Water contents to need for producing high fluid concrete is minimum 170kg/$\textrm{m}^3$ without regard to combined aggregates. 3) The effect of S/a on high fluid concrete by combined aggregates is approximately S/a 50% (type A and B), s/a 50-55% (type C). 4) Consistency measuring of high fluid concrete by K-slump tester is possible and first indication value, high fluid concrete can be produced, is 6~10.5cm.

고로슬래그 미분말을 함유한 고유동 모르터의 유동성상에 미치는 영향 요인에 관한 연구 (A Study on the Factors Affecting the High Fluid Mortar Containing Ground Granulated Blast-furnace Slag)

  • 김재훈;윤상천;지남용
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2002년도 학술.기술논문발표회
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    • pp.29-36
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    • 2002
  • High fluid concrete unlike OPC concrete is made with various material, and the phase of fresh concrete is considerably different. In order to understand fluidity phase and mix properties of high fluid concrete, concrete is required to access as suspension structure which consists of aggregate and paste. The focus of this paper is to analyze the test results and quantify the effect of mix proportions of molar and fineness modulus of ,and on the properties of fresh mortar. The effect of water-binder ratio, sand-binder ration, content; of ggbs (by mass of total cementitious materials), and various contents of water reducing agent on the yield stress and plastic viscosity of the mix is studied. Based on the experimental results, the following conclusion; can be drawn: (1) The mixing time needed (or high fluid mortar was approximately two times more than that of ordinary portland mortar. (2) The fluidity phase of mortar could be explained by yield stress of mix and the fluidity of mortar. (3) As the content of ggbs increased, yield stress of mortar was decreased and plastic viscosity of it was increased. (4) For the high fluid mortar, it was appeared that sand-binder ratio should be below 1.5.

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고로슬래그 미분말을 함유한 고유동 모르터의 유동성상에 미치는 영향 요인에 관한 연구 (A Study on the Factors Affecting the High Fluid Mortar Containing Ground Granulated Blast-furnace Slag)

  • 김재훈;윤상천;지남용
    • 한국건축시공학회지
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    • 제2권4호
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    • pp.145-152
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    • 2002
  • High fluid concrete unlike OPC concrete is made with various material, and the phase of fresh concrete is considerably different. In order to understand fluidity phase and mix properties of high fluid concrete, concrete is required to access as suspension structure which consists of aggregate and paste. The focus of this paper is to analyze the test results and quantify the effect of mix proportions of mortar and fineness modulus of sand on the properties of fresh mortar. The effect of water-binder ratio. sand-binder ration. contents of ggbs (by mass of total cementitious materials). and various contents of water reducing agent on the yield stress and plastic viscosity of the mix is studied. Based on the experimental results, the fellowing conclusions can be drawn: (1) The mixing time needed for high fluid mortar was approximately two times more than that of ordinary portland mortar. (2) The fluidity phase of mortar could be explained by yield stress of mix and the fluidity of mortar. (3) As the content of ggbs increased, yield stress of mortar was decreased and plastic viscosity of it was increased. (4) For the high fluid mortar, it was appeared that sand-binder ratio should be below 1.5.

고강도콘크리트의 고속펌핑을 위한 압송성평가 및 예측모델에 관한 연구 (Development of Evaluation and Prediction Model for Concrete High Speed Pumping)

  • 김형래;조호규;정웅택
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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    • pp.201-203
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    • 2012
  • The establishment of the technology for evaluating friction resistance and pipe pressure and the relation of the fluid characteristics and pumpability of concrete is essential for the evaluation of concrete pumping performance for high speed construction of super-tall building. So, this study focuses on quantitative evaluation of concrete fluid characteristics and surface friction resistance under the change of concrete mix proportion and pumping condition. In this study, we measured the rheology of concrete and pipe pressure and surface friction characteristics when pumping. And, relations between the rheology characteristics of concrete and pumping performance was investigated by experiment. As the result of the experiment, high regression between the surface friction and pressure gradient was confirmed. And, prediction model to evaluate the friction resistance coefficient and pipe pressure reduction coefficient was suggested.

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고유동콘크리트의 유동특성 및 공학적 특성에 미치는 시멘트페이스트용적 및 골재용적과의 관계에 관한 실험적 연구 (The Experimental Study on the Influence of Relation between Cement Paste and Aggregate Volume to Effect the High Folwing and Engineering Properties of High Flowing Concrete)

  • 김규용;최희용;강희관;김무한
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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    • pp.301-307
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    • 1996
  • High flowing concrete has been made using a combination of much amount cementitious materials and addition of SP agents, so that it makes possible to high flowing properties of fresh concrete. In the fluid mechanical and rheological point of view, high flowing concrete is affected on the relation between cement paste and aggregate of volume. In this experimental study, it is measured high flowing concrete of slump-flow about 65$\pm$5cm according to 0.54~0.80 of volume ratio and to analysed the properties of high flowing concrete in fresh and hardened concrete. It is the aim of this study to consider the affection of high flowing properties accoring to cement paste to aggregate ratio of volume on the combination of concrete.

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모델 시험체에 있어서 타설방법과 강도에 대한 실험적 연구 (The Study on Strngth and Placing Method that Used of Mock up Model)

  • 임형일;정근호;박선길;이영도;정상진
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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    • pp.841-846
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    • 2000
  • The purpose of this study is promote perfect of construction and progress of packing ability through comparison and analysis with quality, as placing ways and placing direction are changed. Kinds of concrete are general, high fluidity, and high performance concrete. Classified with concrete as placing ways - direct ways, sheath way - and placing directing - flange direction, web direction - is analyzed section and strength of hardened concrete. The results of this study is belows the more fluid of concrete, the more useful to top-down method.

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타설법에 따른 역타콘크리트의 강도에 관한 연구 (A Study on Strenth of Top-Down concrete on placing ways of kind)

  • 이영도;윤상혁;정근호;정상진
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2002년도 학술논문발표회
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    • pp.37-40
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    • 2002
  • The purpose of this study is promote perfect of construction and progress of packing ability through comparison and analysis with quality, as placing ways and placing direction are changed. Kinds of concrete are general, high fluidity, and high Performance concrete. Classified with concrete as placing ways - direct ways, sheath way - and placing directing - flange direction, web direction - is analyzed section and strength of hardened concrete. The results of this study is belows the more fluid of concrete, the more useful to top-down method.

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고성능 콘크리트의 특성에 미치는 재생골재 치환율의 영향 (The Effect of Replacement Level of Recycled Aggregate on the Properties of High-Performance Concrete)

  • 양근혁;김용석
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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    • pp.181-184
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    • 2004
  • The objective of this experimental study is to grasp the effect of replacement level of high-quality recycled aggregate on the properties of high-performance concrete. The mixing types were divided into two series based on containing $0\%\;and\;15\%$ fly-ash. Replacement level of recycled aggregate ranged from $0\%\;to\;100\%$. Test results showed that the initial slump and the fluid velocity were independent on the replacement level of recycled aggregate, and the loss of compressive strength was almost $20\%$ with the recycled aggregate only.

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고온에 노출된 고강도 콘크리트 기둥의 수치해석 (Numerical analysis of high-strength concrete exposed elevated temperature)

  • 서연주;홍성걸
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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    • pp.21-24
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    • 2005
  • A computational analysis of hygro-thermal and mechanical behaviour of concrete column at high temperature is presented. The objective of this study is to develop a finite difference model that simulates coupled heat and transport phenomena in reinforced concrete structures exposed to rapid heating conditions such as fires. The theoretical basis for the integrated finite difference method is presented to describe a powerful numerical technique for solving of fluid flow in porous media. The numerical results predict the phenomena of 'moisture clog' and the explosive spalling of concrete under fire. The investigations show that high-strength concrete(HSC) and normal-strength concrete(NSC) exposed to high temperature have different pore pressure buildup dependent on porosity, permeability and moisture contents. HSC has more possibility than NSC on spalling.

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Modeling refractory concrete lining of fluid catalytic cracking units of oil refineries

  • Silva, Ana B.C.G.;Andrade, Henrique C.C.;Fairbairn, Eduardo M.R.;Telles, Jose C.F.;Ribeiro, Fernando L.B.;Toledo-Filho, Romildo D.;Medeiros, Jorivaldo
    • Computers and Concrete
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    • 제25권1호
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    • pp.29-36
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    • 2020
  • This work presents a numerical modeling procedure to simulate the refractory concrete lining in fluid catalytic cracking units of oil refineries. The model includes the simulation of the anchors that reinforce the contact between the refractory concrete and the steel casing. For this purpose, the constitutive relations of an interface finite element are set to values that represent the homogenized behavior of the anchored interface. The parameters of this constitutive relation can be obtained by experimental tests. The model includes also multi-surface plasticity, in order to represent the behavior of the refractory concrete lining. Since the complexity of real case applications leads to high computational costs, the models presented here were implemented in a high-performance parallelized finite element platform. A case study representing a riser similar to the ones used by the refinery industry demonstrates the potential of the model.