• Title/Summary/Keyword: Admixture

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The Experimental Study of Inorganic Performanent내s of Fire Resistance Evaluation (무기질계 영구거푸집의 내화성능에 관한 실험적 연구)

  • 김영진;백민수;정근호;김우재;정상진
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.10a
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    • pp.495-500
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    • 2002
  • The purpose of this study is to develop and to apply this permanent cement mortar form as one of those system forms to improve existing form's problems. (1) In the fire proof test with combined specimen, the fire proof covering including form section thickness is satisfied with the fire proof criterion. It is considered that form section thickness has no problem (2) The suitable method of normal pressure steam curing for the form's mass production is 4 hours in 65℃ considering production cost, the silica fume admixture is economic.

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An Experimental Study on the Factors Influencing on the Slump Loss of High Strength Concrete (고강도콘크리트의 유동성 손실에 영향을 미치는 요인에 대한 실험적 연구)

  • 문한영;김기형;문대중
    • Proceedings of the Korea Concrete Institute Conference
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    • 1992.10a
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    • pp.94-99
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    • 1992
  • In this study , some factors such as mix proportion, type and dosage of high range water reducing admixture(HRWR) and natural pozzolanas influencing on the slump loss of high strength concrete(H.S.C) using HRWR were investigated for reducing the slump loss. The acquired results indicated that the slump loss of H.S.C was affected according to cement content, sand percentage and type and dosage of HRWR and fly ash was superior to ground granulated blast furance slag in reducing the slump loss of H.S.C.

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Prediction of Carbonation Process in Concrete (콘크리트 중성화 진행의 예측)

  • 고경택;김성욱;김도겸;조명석;송영철
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.767-770
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    • 1999
  • The carbonation process is affected both by the concrete material properties such as W/C ratio, types of cement and aggregated, admixture characteristics and the environmental factors such as CO2 concentration, temperature, humidity. Based on results of preliminary research on carbonation, this study is to propose a carbonation prediction model by taking into account of prediction model by taking into account of CO2 concentration and W/C ratio among major factors affecting the carbonation process.

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Expansive Properties of Concrete with Variable Curing Condition Using Expansion Admixture (팽창재를 이용한 콘크리트의 양생환경에 따른 팽창특성)

  • 홍상희;김정진;강두용;류현기;한천구
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.143-146
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    • 1999
  • This study is intended to investigate the properties of expansion of concrete under various curing environment with expansive additives. In construction field, expansive additives, which are anaiable to prevent from the diverse cracks caused by drying shrinkage are not expected to accomplish the expantion we expected because of both the absence of the know ledge change, loss of weight and dynamic of elasticty under various unit contents of expansive additives and curing condtion.

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Preperties of Mortar Using Ceramic Wastes (도자기 폐기물을 사용한 시멘트 모르터의 특성)

  • 김기형;최재진;최연왕;신화철
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.103-106
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    • 1999
  • In this study, the properties of mortar using ceramic wastes as admixtures and fine aggregates are considered experimentally. The main chemical of ceramic wastes is SiO2 and micro structure of ceramic wastes is porous. Absorption of ceramic wastes is higher than that of river sand and specific gravity is lower than that of river sand. Flow value of mortar using ceramic waste admixture and fine aggregates is increased more or less and the strength of mortar using ceramic wastes as fine aggregates is increased.

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Sarcomatoid Carcinoma of the Lung - Two cases report - (폐에 발생한 암육종 - 치험 2례 -)

  • 장원기;조중구
    • Journal of Chest Surgery
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    • v.32 no.11
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    • pp.1052-1056
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    • 1999
  • The pulmonary sarcomatoid carcinoma is a rare malignant tumor, which is composed of an admixture of carcinomatous and sarcomatous components, and accounts for 0.3% of all pulmonary neoplasms. Clinicopathological features are often related to anatomical location: central endobronchial type and peripheral parenchymal type. Noninvasive diagnostic test had a low yield in detection sarcomatoid carcinoma. Metastasis to the regional lymph nodes and to distant organ is common. The prognosis is poor and the median survival is about 15 months. We report two cases of pulmonary sarcomatoid carcinoma with review of literatures.

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A Fundamantal Study on the Properties of Cement Mortar Using E.P-dust (EP-DUST를 사용한 시멘트 모르터의 특성에 관한 기초적 연구)

  • 조중동;한민철;조병영;장기영;한천구
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10c
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    • pp.117-120
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    • 1998
  • The objective of this study is to investigate the possibility for application of E.P-dust as both admixture and fillers for aggregates under various mixproportion, replacing method and the ratios of replacement. According to the experimental results, improvement of viscosity and reducing of segregation at fresh state and gain in strength at hardened state can be achieved by applying E.P-dust. It can be considered from the results that application of E.P-dust will be more efficient as fillers for aggregates than as binder

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Relation of Concrete Setting Characteristic and Lateral Pressure in Mass Concrete Wall (매스콘크리트 벽체에서 콘크리트 응결 특성과 측압과의 관계)

  • 박찬규;유재현;백승준;정재홍;진용만
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.935-938
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    • 2001
  • This paper reports the relation of concrete setting characteristic and lateral pressure in mass concrete wall such as side wall of LNG underground storage tank. In order to estimate the lateral pressure, initial setting time of low heat cement concrete with type of mineral admixture was measured for three concrete mixtures(W/P=41.6%) containing limestone powder, fly ash, and slag powder. As a result, the lateral pressure of the concrete containing limestone powder was the smallest than those of other concretes as well as the initial setting time.

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고강도콘크리트의 제물성 향상을 위한 연구

  • 문한영;김기형;문대중
    • Proceedings of the Korea Concrete Institute Conference
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    • 1994.10a
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    • pp.143-150
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    • 1994
  • To improve the qualities of high strength mortar and concrete with high range water reducing admixture, silica fume and gypsum is applied. The flow loss of mortar is reduced and the compressive strength of mortar and concrete is improved by silica fume. And the silica fume is effective for decreasing the temperature of high strength concrete. In addition to, the strength of high strength concrete is more improved by the gypsum.

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A Study on the Fundamental Properties of High-Strength Concrete Using Ground Granulated Blast-Furnace Slag as an Admixture (고로슬래그 분말을 혼화재로 사용한 고강도콘크리트의 기초적 성질에 대한 연구)

  • 문한영;최연왕;문대중;송용규
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.04a
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    • pp.30-35
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    • 1995
  • This paper presents fundamental experiment for the properties of high performance concrete in its fresh and hardened state made with ground granulated blast-furnace (GGBF) slag. The result is that the effect of decreasing xoncrete temperature is to the mixing ratio of GGBF slag, but it presents disadvantage in the slump loss phase. In addition to, we know that the splitting tensile strength, compressive strength and elastic modulus of concrete mixed with high fineness GGBF slag are increased at age 28days.

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