• 제목/요약/키워드: Unit water content

검색결과 361건 처리시간 0.029초

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

  • 신홍철;우영제;강석표;김규용;정하선;이석홍;손영현;김무한
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
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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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단위수량 및 증점제량이 콘크리트의 블리딩에 미치는 영향 (Influence of Unit Water and Viscosity Agents Contents on the Bleeding of Concrete)

  • 김은호;심보길;황인성;전충근;한천구
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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    • pp.232-328
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    • 2001
  • This paper investigates the influences of water content and viscosity agent on the bleeding of concrete. According to test results, fluidity shows decline tendency as water content decreases, and dosage of viscosity agent increases. PEO viscosity agent does not affect the air contents while, MC viscosity agent causes air loss. As for bleeding, bleeding decreases with decrease of water content. As dosage of viscosity agent increase, bleeding decreases, regardless of viscosity kinds. It is thought that viscosity agents have the favorable effect of reducing bleeding, if fluidity and air loss are improved.

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減水劑가 콘크리트에 미치는 影響 (Effects of the Water Reducing Agent on the Concrete)

  • 김종천;도덕현
    • 한국농공학회지
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    • 제24권2호
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    • pp.67-75
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    • 1982
  • A study on the effect of water reducing agent on the various characteristics of concrete has been conducted. The experimental results of the study are summarized as follows. 1. Slump test for the concrete added water reducing setretarding agent in proper quantity have been conducted. According to the test results, the decreasing rate of slump value become bigger than plain concrete with increase of the unit weight of cement and elapse of time 2. In case the proper quantity content of maximum compressive strength in Fig. 5 of water reducing set retarding agent is added, unit weight of water is decreased about 15% or so as compared with plain concrete. with the increase of water reducing set accelerating agent content unit weight of water is decreased much more, And other hand, amount of air entraining shows the increasing tendency with the increase of water reducing agent content. 3. The adding rate of water reducing agent which produce maximum strength shows that WR-CH and WR-SA which is water reducing set-starding agent is 0.2% and WR-CO is 0.5% and that WS-PO which is water reducing set accelerating agent is 0.5 4. compressive strength jof the concrete made of sulfate resistant cement shows less than the strength of normal portland cement at initial strength but the strength of both cement shows almost same at curing age of 28 days. 5. when proper quantity of water reducing set retarding agent is used, boned strength is increased about 15% at curing age of 28days. 6. According to the result of durability test, dynamic young's mudulus of elasticity at plain concrete is decreased about 50% as compared with initial step at 300 cycle of freezing and thawing after curing age of days. on the contarary the concrete used water reducing agent is decreased less than 7%.

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점토-시멘트 혼합 지반의 물리적 특성 예측 (Prediction of Physical Characteristics of Cement-Admixed Clay Ground)

  • 박민철;전제성;정상국;이송
    • 대한토목학회논문집
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    • 제34권2호
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    • pp.529-536
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    • 2014
  • 점토-시멘트 혼합토의 물리적 특성인 함수비, 비중, 단위중량과 간극비 등은 혼합토의 강도, 압축성, 압밀거동 예측 등에 적용되는 주요한 인자이다. 기존에는 혼합토의 물리적 특성을 복잡한 실내시험 및 시공 후 확인조사를 통해 이루어 졌다. 본 연구는 점토 함수비 90~170%, 시멘트 함유율 5~25%와 재령기간은 3~90일 조건으로 실내시험을 수행하였으며, 양생 후 혼합토 함수비, 비중, 단위중량과 간극비 등에 대한 변화를 분석하였다. 시험결과를 이용하여 원지반 점토 함수비, 시멘트 함유율과 재령기간 등의 역학적 관계를 바탕으로 혼합토의 함수비, 비중과 단위중량에 관한 물성 예측식을 제안하였다. 혼합토의 물성 예측식을 지반공학 분야에서 일반적으로 사용하는 간극비 산출식에 대입하여 혼합토의 간극비 예측식을 도출하였으며, 방콕 점토를 대상으로 간극비에 대한 실험결과와 본 연구에서 제안한 예측식을 검증하였다.

Flat TDR 시스템을 이용한 흙의 함수비와 건조단위중량 측정 (Water Content and Dry Density Measurement of Soil Using Flat TDR System)

  • 김완민;김대현;서혁
    • 한국지반공학회논문집
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    • 제33권11호
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    • pp.5-19
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    • 2017
  • 본 연구는 전통적인 다짐관리방법의 문제점을 보완하고자 TDR(Time Domain Reflectometry)을 이용하여 지반의 함수비와 건조단위중량을 측정하는 연구를 수행하였다. 개발된 Flat TDR 시스템의 측정값을 검증하기 위해 여섯 가지 시료를 대상으로 실내실험을 수행하였다. 또한 실내실험을 바탕으로 현장시험을 수행하여 현장 적용성을 검토하였고, 신뢰성을 확보하기 위해 Purdue TDR 시스템과 비교실험을 수행하여 정밀도를 확인하였다. 또한 유한요소해석을 수행하여 Flat 프로브의 영향범위를 확인하였다. 그 결과 약 10cm의 영향범위를 확인하였고, 실내실험결과 함수비는 평균적으로 약 0.4%의 오차를 보이며, 건조단위중량의 경우 약 1.6%의 오차를 보였다. 현장시험의 경우 함수비는 0.8%, 건조단위중량의 경우 2.5%의 오차를 보였다. 실험 결과를 통하여 Flat TDR 시스템의 측정값은 기존의 TDR 시스템보다 정확한 값을 도출하는 것을 확인할 수 있었다.

잔골재 종류 및 감소제 첨가율에 따른 콘크리트의 공학적 특성에 관한 실험적 연구 (An Experimental Study on the Engineering Properties of Concrete with Kind of Fine Aggregate and Addition Ratio of Water Reducing Agents)

  • 신관수;나철성;백용락;최세진;김규용;김무한
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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    • pp.157-160
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    • 2006
  • Recently, trouble of sand supply is occurred according to exhaustion of natural sand resources. To solve this problem, sea sand and crushed sand are used. But, necessity of water reducing agent because quality of concrete that use sea sand and crushed sand is deteriorated. Therefore in this study was examined on the engineering properties of concrete with kind of fine aggregate and addition ratio of water reducing agents. As a result, compressive strength appeared similar standard regardless of kind of fine aggregate. Compressive strength, durability was similar in decrease of the unit water content by increase of addition ratio of the water reducing agent. Also, drying shrinkage resistivity was improved because the unit water content decreased.

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레미콘 단위수량 산포가 콘크리트 강도 및 내구성에 미치는 영향 (An Influence of Unit-Water Content Distribution in Ready-Mixed Concrete on Strength and Durability of Concrete)

  • 우영제;이한승;정상화
    • 콘크리트학회논문집
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    • 제20권3호
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    • pp.375-381
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    • 2008
  • 레미콘 제조오차에 의한 콘크리트내의 물의 수량이 증가하면 내구성저하 등의 다양한 문제점을 야기하게 된다. 이러한 이유로 여러 방법들 중에 단위수량의 신속측정법인 정전용량법, 고주파가열법, 단위용적질량법을 이용하여 단위수량의 변동을 관리하고 있으며, 특히 일본의 경우에는 단위수량 변동 ($\pm$ 10, 15, 20 kg/$m^3$ 등)에 대한 관리지침을 규정하여 관리하고 있다. 그러나 일본에서 규정하고 있는 각종 지침들이 내구성 저하도를 고려하지 않은 상태에서 제조오차와 측정오차를 확률적으로 고려한 불확도 개념에서 합부판정 기준을 정하고 있는 실정이다. 이에 본 논문에서는 불확도 개념뿐만 아니라 실제 수량 산포에 따라 내구성 저하에 미치는 영향을 검토하고자 수량을 추가로 첨가하여 동결융해, 중성화, 염해를 중심으로 내구성 저하도를 측정하였다. 이상의 실험 결과 일반강도 범위 내에서 15 kg/$m^3$ 이상의 수량이 추가로 첨가 되었을 경우 콘크리트의 성능 저하 효과가 크기 때문에 설계된 내구 성능의 적정 수준 이상을 유지하기 위해서는 배합 설계된 단위수량에 대한 품질관리에 유의할 필요가 있다.

굵은 골재 입형 개선이 고성능콘크리트의 충전특성에 미치는 영향 (Influence of the Improveal Grain Shape of Coarse Aggregates on Compactability of High Performance Concrete)

  • 이승한;김희중;정용욱
    • 콘크리트학회논문집
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    • 제12권4호
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    • pp.103-111
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    • 2000
  • The influence of the improvement of grain shape of the coarse aggregate to the unit powder content of concrete and the fine aggregate ratio for the increase of the flowability and segregation resistance of high performance concrete was examined. According to the experimental results, flowability and compacting of concrete presents best states in the S/a which has the smallest 패야 ratio. The coarse aggregate after improvement of grain shape, that has changed from the 0.68 of spherical rate of disk shape to 0.73, led fine aggregate ratio to be down 6% (i.e from 47% to 41%). The improvement of grain shape of the coarse aggregate also led the lowest unit powder content to be down 60kg/㎥ (ie from 530kg/㎥ to 470kg/㎥). And approximate 10% of unit water content has been reduced as unit powder content was down. However, the compressive strength after the improvement of grain shape of the coarse aggregate decreased to 5% due to decrease of adhesiveness of the aggregate and cement paste.

경량기포혼합 준설토의 강도특성 (Strength Characteristics of Light-Weight Cement mind Marine Clay with Foam)

  • 박건태;김주철;윤길림;이종규
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2002년도 봄 학술발표회 논문집
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    • pp.483-490
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    • 2002
  • A massive amount of marine clay produced as dredging of coast and sea bed is often dumped in open sea and filled in pond. The treatment of marine clay demand a large area and make fatal environmental problems for echo system. This research work intend to manufacture a light-weight landfill materials which are produced by mixing the dredged marine clay with various amount cement and foam. An extensive Uniaxial and Triaxial compression test are carried out to investigate the strength characteristics of the light-weight cement mixed marine clay with foam under various test conditions. The results indicated that the required unit weight has been achieved with negligible change after 28days curing time in water. It is also recognized that the compressive strength of light-weight landfill materials linearly decrease with increasing initial water content, and the rate of strength decrease with increasing initial water content in water curing was smaller than that of air curing Futhermore, the rate of strength decreased with increasing initial water content, however, the rate become smaller as cement content increased.

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