• Title/Summary/Keyword: High Fluidity Concrete

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An Experimental Study on the Effect of Cement and High range water reducing AE agent in Fluidity of High Flowing Concrete (고유동콘크리트의 유동특성에 미치는 시멘트 및 고성능 AE감수제의 효과에 관한 연구)

  • 김규용;반성수;박선규;박유신;신홍철;김무한
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04a
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    • pp.63-68
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    • 1998
  • The fluidity of high flowing concrete can be affected by numerous parameters which characterize either the cement of the admixture. The reactivity of a cement as determined by its chemical composition(especially its $C_3$A content), its fineness and its content in sulfates and alkalies obviously plays a key role in rheology of high flowing concrete in fresh state. Specific properties of high range water reducing AE agent used to enhance the workability of high flowing concrete also exert important influence. The purpose of this experimental study is to investigate and analyze the effect of cement and high range water reducing AE agent in fluidity, setting, compressive strength of high flowing concrete. As a result, we found that fluidity of high flowing concrete is affected greatly by kind of cement and high range water reducing AE agent, also, there is harmonic character between high belite cement and polycarbonic acid high range water reducing AE agent.

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Effect of Powder and Aggregates on Compactability of High Performance Concrete

  • Lee, Seung-Han;Han, Hyung-sub
    • KCI Concrete Journal
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    • v.11 no.3
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    • pp.19-28
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    • 1999
  • This study treated self-compacting high Performance concrete as two Phase materials of Paste and aggregates and examined the effect of powder and aggregates on self-compacting high performance, since fluidity and segregation resistance of fresh concrete are changed mainly by paste. To improve the fluidity and self-compactibility of concrete, optimum powder ratio of self-compacting high performance concrete using fly ash and blast-furnace slag as powders were calculated. This study was also designed to provide basic materials for suitable design of mix proportion by evaluating fluidity and compactibility by various volume ratios of fine aggregates, paste, and aggregates. As a result, the more fly ash was replaced, the more confined water ratio was reduced because of higher fluidity. The smallest confined water ratio was determined when 15% blast-furnace slag was replaced. The lowest confined water ratio was acquired when 20% fly ash and 15% blast-furnace slag were replaced together. The optimum fine aggregates ratio with the best compactibility was the fine aggregate ratio with the lowest percentage of void in mixing coarse aggregate and fine aggregate In mixing the high performance concrete. Self-compacting high performance concrete with desirable compactibility required more than minimum of unit volume weight. If the unit volume weight used was less than the minimum, concrete had seriously reduced compactibility.

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Fluidity Retention of Cement-Based Composites Using High range water reducing AE agent (고성능AE감수재를 사용한 시멘트복합체의 유동성 유지성능)

  • 김기형;김인수
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10c
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    • pp.93-98
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    • 1998
  • Fluidity retention of concrete used high range water reducing AE agent(HWAE) is varied according to type, dosage amount and dosing method of HWAE. The type and substitution ratio of mineral admixture also have influence on the fluidity retention of concrete using HWAE. For the purpose of improving the fluidity retention in concrete used HWAE, 3 types of HWAE and ground granulated blast furnace slag(SG) are applied in cement-based composites such as cement paste, mortar and concrete respectively. According to using the HWAE of naphthalene sulfonates and SG, the fluidity retention of mortar and concerete is improving the fluidity retention and strength of concrete regardless of type of HWAE.

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Influence of High Fluidity Concrete on Segregation Resistance When Replacing Mineral Admixture (광물질 혼화재 치환이 고유동 콘크리트의 재료분리 저항성에 미치는 영향)

  • Lee, Hyuk-Ju;Lee, Young-Jun;Hyun, Seung-Yong;Han, In-Deok;Han, Dong-Yeop;Han, Min-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.05a
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    • pp.139-140
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    • 2019
  • In this study, we considered the influence on segregation resistance at the time of substitution of FA and BS, which are substance admixtures of high fluidity concrete. According to the research results, EIS, which is an index of segregation in high fluidity concrete replacement, showed a low value, and the composition also showed a higher value than OPC. Therefore, it is confirmed that the resistance to segregation at the time of admixture replacement of high fluidity concrete is improved.

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The Optimum Mix Design of 40MPa, 60MPa High Fluidity Concrete using Neural Network Model (신경망 모델을 이용한 40MPa, 60MPa 고유동 콘크리트의 최적배합설계)

  • Cho, Sung-Won;Cho, Sung-Eun;Kim, Young-Su
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.05a
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    • pp.223-224
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    • 2021
  • Recently, the demand for high fluidity concrete has been increased due to skyscrapers. However, it has its own limits. First of all, high fluidity concrete has large variation and through trial & error it costs lots of money and time. Neural network model has repetitive learning process which can solve the problem while training the data. Therefore, the purpose of this study is to predict optimum mix design of 40MPa, 60MPa high fluidity concrete by using neural network model and verifying compressive strength by applying real data. As a result, comparing collective data and predicted compressive strength data using MATLAB, 40MPa mix design error rate was 1.2%~1.6% and 60MPa mix design error rate was 2%~3%. Overall 40MPa mix design error rate was less than 60MPa mix design error rate.

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A Fundamental Study on the Mix Design in High Volume Fly-Ash Concrete (플라이애시를 대량 사용한 콘크리트의 배합설계를 위한 기초적 연구)

  • 심재형;김재환;최희용;강석표;최세진;김무한
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.641-646
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    • 2001
  • Generally, when Fly-Ash was used as replacement material of cement in concrete, it might occur retardation of setting and hardening. So, it is unable to use a large amount of Fly-Ash as replacement for cement. However, if it is used as replacement material of fine aggregate in concrete, we can use a large amount of Fly-Ash and settle a problem of natural-aggregate exhaustion. Furthermore, engineering properties of High Volume Fly-Ash Concrete Is better than that of plain concrete But, the larger Fly-Ash is replaced, the more fluidity of High Volume Fly-Ash Concrete decrease, because porous organization of Fly-Ash adsorb water and Superplasticizer. In this study, after appending additional water to High Volume Fly-Ash Concrete in proportion to weight of Fly-Ash, we intend to find proper ratio which doesn't affect strength and satisfy fluidity As a result of this study, it was found that fluidity of mortar with 25~28 percentage of additional water was satisfied with fluidity of plain mortar, and compressive strength of that was similar to plain mortar's

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Execution of High Fluidity Concrete by Flowing Method (유동화 공법을 적용하여 제조한 고유동 콘크리트의 시공)

  • 한민철;손성운;한천구
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2001.11a
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    • pp.28-33
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    • 2001
  • This paper presents the results of mock up test on the manufacturing of high fluidity concrete by applying flowing methods with segregation reducing type superplasticizer(SRS). Three kinds of mock up structure are made such as. conventional concrete(A), high fluidity concrete(B) and high fluidity concrete incorporating 20% of fly ash(C). Physical and mechanical properties, temperature history of structure and nondestructive test are performed. Segregation reducing type superplasticizer is put into base concrete at field, and base concrete is also flowed at field. C mock up structure which requires 0.85% of SRS to flow base concrete shows most desirable performance at fresh state. The highest rising temperature shows the lowest at C structure among the tested structures. Strength variations before and after flowing also show the lowest values at C structures.

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An Experimental Study on the Mix Proportion in Fluidity and Engineering Properties of High Flowing Concrete (고유동콘크리트의 유동특성 및 공학적특성에 미치는 조합요인에 관한 실험적 연구)

  • 신홍철;우영제;강석표;김규용;정하선;이석홍;손영현;김무한
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10a
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    • pp.307-312
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    • 1998
  • Recently the study on high flowing concrete which has high workability and Self-compacting is being proceeded actively in the university and corporative laboratory. There are some cases that has been applied to the field. This high flowing concrete has higher fluidity and segregation resistance than Plain of flowing concrete. And it is being focused as a remarkable know-how which can make high-quality concrete and reduction effect of labor force. This properties of high flowing concrete are influenced by the relationship of several factors; binder content, water binder ratio and unit water content. It is the aim of this study to propose reference data at mix design of high flowing concrete, after comparing and analyzing the fluidity and strength properties of high flowing concrete according to water binder content ratio and unit water content.

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Possibility Analysis on Reducing Formwork Leakage of High-fluidity Mortar by Using PVA and Borax (PVA 및 붕사를 사용한 고유동 모르타르의 거푸집 누출량 저감 가능성 분석)

  • Kim, Young-Ki;Lee, Yu-Jeong;Heo, Jun-Ho;Han, Dongyeop
    • Journal of the Korea Institute of Building Construction
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    • v.22 no.2
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    • pp.125-136
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    • 2022
  • This research is to reduce the formwork leakage of high-fluidity concrete caused by insufficient accuracy of formwork fabrication widely used for high-fluidity concrete to general strength concrete. However, in the actual construction site, because of the insufficient accuracy of formwork fabrication may cause leaking concrete of mortar through a gab of the formwork. Therefore, in this research, which builds on previous research into providing thixotropy with PVA and Borax, the use of thixotropy to reduce high-fluidity mortar leakage was evaluated. The results of the experiment proved that the use of thixotropy with PVA and Borax can contribute to reduction of the formwork leakage of high-fluidity mortar. This finding is expected to lead to further research on reducing leakage of high-fluidity concrete.

Drying Shrinkage of High-Fluidity Polymer-Modified Paste (고유동 폴리머 시멘트 페이스트의 건조수축)

  • Joo, Myung-Ki;Lee, Youn-Su;Yeon, Kyu-Seok
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.929-932
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    • 2006
  • The effects of polymer-binder ratio, antifoamer content and shrinkage-reducing agent content on the setting time and drying shrinkage of high-fluidity polymer-modified pastes are examined. As a result, the setting time of the high-fluidity polymer-modified pastes tends to delayed with increasing polymer-binder ratio. Irrespective of the antifoamer content, the drying shrinkage of the high-fluidity polymer-modified pastes tend to decrease with increasing polymer-cement ratio and shrinkage-reducing agent content.

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