• Title/Summary/Keyword: Slump Flow Test

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An Experimental Study on the Properties of Ultra High Strength Concrete for Replacement of Silica Fume & Fly Ash (실리카흄 및 플라이애쉬의 치환율 변화에 따른 초고강도 콘크리트의 특성에 관한 실험적 연구)

  • 윤기원;조병영;한천구;반호용
    • Proceedings of the Korea Concrete Institute Conference
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    • 1994.10a
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    • pp.157-160
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    • 1994
  • Recently, many studies on the ultra high strength concrete are performed in our country. so, this study is aimed for analyzing the effects for replacement of silica fume and fly ash. As results, slump, slump flow and compressive strength is showed the high values in replacement silica fume. Tensile strength ratio is 1/17 and bending strength ratio is 1/6 for compressive, there are results of the test.

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A Comparison Study Between Evaluation Methods on the Rheological Properties of Cement Paste (시멘트 페이스트의 유동 특성에 관한 평가방법 비교연구)

  • Han Cheon-Goo;Lee Gun-Cheol;Heo Young-Sun
    • Journal of the Korea Institute of Building Construction
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    • v.6 no.3 s.21
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    • pp.75-82
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    • 2006
  • This study investigates the influence of various blending factors on cement paste fluidity and find out the most effective evaluation method of cement paste flow, comparing flow test apparatuses such as ring flow(R-F), flow cone(F-C) and mini slump(M-S). A viscometer also measures the rheology coefficients to secure faithful numerical data. Firstly, series I examines cement paste, affected by several cement products and mineral admixture types in the range of W/B 40%, ordinary fluidity, and W/B 30%, high fluidity. In this series, the three types of cement product depended on companies, are randomly used and the mineral admixture, such as fly ash, blast furnace slag and silica fume, are incorporated in the cement paste, in response to the ratio of 10, 20, to 30%, respectively. In addition, series II studies various chemical admixture types, affecting the cement paste. This series is carried out with manufacturing companies and component types in the range of W/C 30%, high fluidity. For the manufacturing companies, randomly four products are used and for the component types, polycaboxylate, melamine, naphthalene and lignosulfonate type are chosen. Test results showed that in the fluidity test of cement paste considering various types of blending factors, R-F exhibited similar tendency with F-C and M-S. In the analysis of consistency curves measured by viscometer, the fluidity evaluation method using flow test apparatuses was significantly effective, except for the some of the low fluidity specimens. In conclusion of this study, R-F was the most convenient, faithful and effective fluidity evaluation method of cement paste.

Development of Flowability Measurement Device using Laser Diode (레이져 다이오드를 이용한 유동성능 측정장치 개발)

  • Jeong, Jae-Gwon;Kim, Kyung-Hwan;Eom, Joo-Han;Choi, Yun-Wang
    • Proceedings of the Korea Concrete Institute Conference
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    • 2009.05a
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    • pp.247-248
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    • 2009
  • Testing standards both nationally and abroad for high flowing concrete are presented about slump flow and the time to reach 500 mm. However, the slump flow testing method to measure flow properties of high flowing concrete results in measurement error due to the differences in each person's perception of the test. This study introduced laser diode to reduce such testing errors from personal differences in experimental procedure.

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A Study on the factors of Quality variation for High Flowing Concrete in Site (고유동 콘크리트의 품질변동 요인에 관한 연구)

  • Kwon Yeong-Ho;Lee Hyun-Ho;Lee Hwa-Jin;Ha Jae-Dam
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.743-746
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    • 2004
  • This research investigates experimentally an effect on the properties of the high flowing concrete according to variations of concrete materials and site conditions. Variations of sensitivity test are selected items as followings; (1)Concrete temperature, (2)Unit water(Surface moisture of fine aggregate), (3)Fineness modulus of fine aggregate, (4)Addition ratio of high-range water reducing agent. And fresh conditions of the high flowing concrete should be satisfied with required range including slump flow$(65{\pm}5cm)$, 50cm reaching time of slump flow$(4\~10sec)$, V-box flowing time$(10\~20sec)$, U-box height(min.300mm) and air content$(4{\pm}1\%)$. As results of sensitivity test, material variations and site conditions should be satisfied with the range as followings; (1)Concrete temperature is $10\~20^{\circ}C$ (below $30^{\circ}C$), (2)Surface moisture of fine aggregate is within ${\pm}0.6\%$, (3)Fineness modulus of fine aggregate is $2.6{\pm}0.2$ and (4)addition ratio of high range water reducing agent is within $1\%$ considered flow-ability, self-compaction and segregation resistance of the high flowing concrete.

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The Quality Properties of Self-Compacting Concrete Mixed with Tailing from the Sangdong Tungsten Mine (상동광산 광미를 혼합한 자기충전 콘크리트의 품질 특성)

  • Choi, Yun-Wang;Kim, Yong-Jic;Choi, Wook
    • Journal of the Korea Concrete Institute
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    • v.18 no.6 s.96
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    • pp.777-783
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    • 2006
  • This study has focused on the possibility for recycling of tailings from the Sangdong tungsten mine as powder(TA) of self-compacting concrete(SCC). The experimental tests for slump-flow, time required to reach 500 mm of slump flow(sec), time required to flow through V-funnel(sec) and filling height of U-box test(mm) were carried out in accordance with the specified by the Japanese Society of Civil Engineering(JSCE). The results of this study, slump-flow of SCC was satisfied a prescribed range. And time required to reach 500 mm of slump flow(sec) and time required to flow through V-funnel(sec) decreased with increasing replacement of TA. But filling height of U-box test(mm), replacement of TA up to 30% were satisfied a prescribed range. The mechanical properties including compressive strength, splitting tensile strength and elastic modulus were checked with the requirements specified by Korean Industrial Standards(KS). The compressive strength of SCC decreased with increasing replacement of TA, splitting tensile strength and elastic modulus were similar to those of normal concrete. The fundamental durability was reviewed through the dry shrinkage rate and accelerated carbonation tests. As the result dry shrinkage rate and accelerated carbonation depth increased with increasing replacement of TA.

Flowability and Strength of Self-compacting Concrete Mixed with Tailings from the Sangdong Tungsten Mine (상동관상 광미를 혼합한 자기충전콘크리트의 유동 및 강도 특성)

  • Choi, Yun Wang;Kim, Yong Jic;Jung, Moon Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.4A
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    • pp.767-774
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    • 2006
  • This study has focused on the possibility for recycling of tailings from the sangdong tungsten mine as powder (TA) of self-compacting concrete (SCC). The experimental tests for entrapped water ratio were carried out in accordance with the specified method by Okamura. The rheological measurements of cement paste were conducted by using a commercially digital Brookfield viscometer (Model LVDV-II+) equipped with cylindrical spindles, also tests for slump-flow, time required to reach 500 mm of slump flow (sec), time required to flow through V-funnel (sec) and filling height of U-box test (mm) were carried out in accordance with the specified by the Japanese Society of Civil Engineering (JSCE). The results of this study, entrapped water ratio was decreased with increasing replacement of TA. Thickness of pseudo water film was increased, and mean plastic viscosity was decreased with increasing replacement of TA. And slump-flow of SCC was decreased with increasing replacement of TA. But time required to reach 500 mm of slump flow (sec), time required to flow through V-funnel (sec) and filling height of U-box test (mm) were satisfied a prescribed range. The mechanical properties including compressive strength, splitting tensile strength and elastic modulus were checked with the requirements specified by Korean Industrial Standard (KS). The compressive strength of SCC was decreased with increasing replacement of TA, splitting tensile strength and elastic modulus were similar to those of normal concrete.

Bond Strength of Reinforcing Steel to High Strength, High Flow Belite Concrete (고강도, 고유동 Belite 콘크리트의 부착성능)

  • 김상준;조필규;이세웅;최완철
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04b
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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.

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An Experimental Study on Workability for Practical Use of High-Performance Concrete (고성능 콘크리트의 실용화를 위한 시공특성에 관한 실험적 연구)

  • Yang, Keun-Hyeok;Lee, Young-Ho
    • Journal of the Korea Institute of Building Construction
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    • v.3 no.1
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    • pp.139-146
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    • 2003
  • The special requirements of high-performance concrete(HPC) could be enhanced property over others such as compressive strength, durability, and construction practices. In order to satisfy these requirements a series of laboratory trial mixes and following mock-up test of reinforced concrete wall at field were performed in this study. The objective of this study was to quantitatively evaluate the workability, compressive strength, and the increased heat of hydration caused by the increase of the specific weight of cement according to various variables. Six example series designed about a minimum compressive strength of 500kgf/$\textrm{cm}^2$ at 28 days, and an approximately slump and slump flow of 25cm and 60cm respectively were tested. The selection process of the specific weight of water and the percentage of fly-ash transposition determined to be most suitable for the production of HPC is presented in the following paper.

Manufacture of Ultra High Strength Concrete using Industrial by-products (산업부산물을 활용한 초고강도콘크리트의 제조)

  • Moon, Han-Young;Kim, Byoung-Kwon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.3
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    • pp.153-162
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    • 2001
  • This paper presents the fundamental study on rational manufacture of Ultra High Strength(VHS) concrete using industrial by-products as like silica fume, slag and fly ash. In this study, we had tested various mixing cases to manufacture the UHS concrete(target compressive strength : over $1,000kgf/cm^2$) which is easily workable (target slump flow : $60{\pm}10cm$). The main variables are studied: 1) to find the optimum replacement ratio of mineral admixture. 2) to find a rational water-binder ratio and a proper binder content. 3) to find the method for reduction of slump loss. From the test results, it is concluded that the rational mix design can be made by using 40% slag, 10% silica fume. We found that compressive strength of UHS concrete increases according to decreasing W/B ratio but in W/B ratio 18~20%, the difference is vague and the compressive strength does not necessarily increase according to increasing binder content over 700kg.

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Spalling Properties of High Strength Concrete Mixed with Various Mineral Admixtures Subjected to Fire

  • Han, Cheon-Goo;Han, Min-Cheol;Heo, Young-Sun
    • International Journal of Concrete Structures and Materials
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    • v.2 no.1
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    • pp.41-48
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    • 2008
  • This study investigates the spalling properties of high strength concrete designed with various types of mineral admixture and diverse content ratios of polypropylene (PP) fiber. Experimental factors considered in series I are four pozzolan types of mineral admixture and series II consists of three shrinkage reducing types of mineral admixture. PP fiber was added 0.05, 0.10 and 0.15vol. % in each mixture of series I and series II, so that totally 27 specimens including control concretes in each series were prepared. Test results showed that the increase of fiber content decreased the slump flow of fresh concrete and increased or decreased the air content depending on the declining ratio of slump flow. For the properties of compressive strength, all specimens were indicated at around 50 MPa, which is high strength range; especially all specimens in series II were 60 MPa. Fire test was conducted in standard heating curve of ISO 834 with ${\phi}100{\times}200\;mm$ size of cylinder moulds for 1 hour. The specimens incorporating silica fume exhibited severe spalling and most specimens without the silica fume could be protected from the spalling occurrence in only 0.05vol % of PP fiber content. This fire test results demonstrated that the spalling occurrence in high strength concrete was not only affected by concrete strength related to the porosity of microstructure but also, even more influenced by micro pore structure induced by the mineral admixtures.