• Title/Summary/Keyword: 고분말도

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Properties of Strength Development of Concrete Using High Fineness Cement and Blast Furnace Slag (고분말도 시멘트와 고로슬래그 미분말을 사용한 콘크리트의 강도발현 성상)

  • Kim, Han-Sic;Ha, Jung-Soo;Lee, Young-Do
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.05a
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    • pp.197-198
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    • 2018
  • As part of the effort to shorten the construction period, this study examined the strength expression characteristics at the early age of concrete using high fineness cement and blast furnace slag. accordingly to provide a basic data on how to solve the problem that the initial strength is lowered.

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Fundamental Physical Properties of Cement Composites Containing Fineness Reject Ash (고분말 리젝트애시를 혼입한 시멘트복합체의 기본물성에 관한 연구)

  • Lee, Kang-Pil;Hong, Man-Gi;Lee, Sang-Soo;Song, Ha-Young
    • Journal of the Korea Institute of Building Construction
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    • v.11 no.4
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    • pp.363-370
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    • 2011
  • This study considerated reject ash, wastes of coal-fired power plants, to use mineral admixtures for cement. The pozzolan activity selected the fineness of the efficient reject ash through comparison and it compared to the fly ash that are widely used for concrete mixed material. Cement composites was prepared replacing of slag cement by fineness reject ash and fly ash, and properties of cement composites was tested by paste(setting time, fluidity, instrumental analysis) and mortar(compressive strength). Instrumental analysis results showed hydration reaction of fineness reject ash was not different from fly ash, but had more dense micro structures. Results of physical properties showed fineness reject ash shorten setting time, increased compressive strength compared by fly ash. Therefore using fineness reject ash with $6,000cm^2$/g to concrete mineral admixtures or cement composites was might be possible and could contribute to improve properties of concrete.

A Study on Properties of High Blaine Cement for Shotcrete (숏크리트용 고분말도 시멘트의 특성)

  • Kim, Jae-Young;Kim, Teuk-Jun;Lee, Min-Suk;Ryoo, Dong-Woo
    • Journal of the Korea Concrete Institute
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    • v.22 no.5
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    • pp.633-640
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    • 2010
  • This study was performed to get basic information about properties of high blaine cement for shotcrete use. Particle size distribution, setting time and compressive strength test, analysis like as SEM, DSC thermal analysis, XRD was carried out to investigate principle properties of high blaine cement. Setting time of high blaine cement was shorter and compressive strength was higher than those of ordinary portland cement (OPC). Results of analysis showed early hydration products of high blaine cement is smaller and spread widely due to increased specific surface. From the SEM observation and analysis of DSC and XRD results, it was seen that the aluminates accelerators promoted calcium aluminium hydrates while the alkali free accelerators increased ettringite and monosulfates formation. Strength and setting time measurement of cement paste with aluminate accelerator is more effective than the alkali free accelerator in reducing the setting time and increasing early strength while alkali free accelerator is more effective in increasing the strength after 7 days.

액정 폴리에스테르의 합성 및 light intensity를 통한 액정성의 확인

  • 최선호;김환철;박병기;김학용
    • Proceedings of the Korean Fiber Society Conference
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    • 1998.10a
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    • pp.87-89
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    • 1998
  • 액정 고분자는 고분자가 용융 또는 용액상태에서 결정성을 보이는 고분자를 말하며, 그 중에서도 열방성 액정 고분자(thermotropic liquid crystalline polymer)는 열에 의하여 액정성을 나타내는 고분자를 말한다. 이 액정 고분자는 용융점(T$_{m}$ )이상에서도 결정이 존재하여 액상의 고분자와 결정을 형성하고 있는 고분자가 상존하는 열적 성질을 가지는 것이 큰 특징이며, 내열성과 기계적 강도 등의 우수한 물리적 성질을 나타낸다. (중략)

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An Experimental Study on Hydration and Strength Development of High Blain Cement at Low Temperature (저온환경에서 고분말도 시멘트의 수화반응 및 강도발현 특성에 관한 실험적 연구)

  • Mun, Young-Bum;Kim, Hyeong-Cheol;Choi, Hyun-Kuk;Kim, Jae-Young;Lee, Han-Seung;Kim, Mok-Kyu
    • Journal of the Korea Institute of Building Construction
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    • v.15 no.4
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    • pp.367-373
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    • 2015
  • In this study, fundamental properties of cement were reviewed to apply high fineness cement at low temperature environment. The classified high fineness cement has large proportion of particles below $10{\mu}m$ which affects early hydration: an overall reaction of cement hydration faster. As a result of using high fineness cement, setting time of concrete was reduced and compressive strength was higher than OPC at all ages. Especially, compressive strength was more than double its value compared with OPC after three days curing in low temperature. Faster reaction and higher heat of hydration was verified by calorimetry early and maximum heat of hydration was analyzed by adiabatic temperature raising test. The analysis of this study confirmed that high fineness cement can be suitable to be used in low temperature environment.

Physical Characteristics of Concrete Using High-Fineness Cement and Fly Ash (고분말도 시멘트와 플라이애시를 사용한 콘크리트의 물리적 특성)

  • Lee, Young-Do;Ha, Jung-Soo;Kim, Han-Sic
    • Journal of the Korea Institute of Building Construction
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    • v.19 no.4
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    • pp.323-330
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    • 2019
  • The cement industry is considered a major industry for reducing greenhouse gases, increasing the amount of binding materials that can replace cement in concrete is known as the most effective method for reducing carbon dioxide. Therefore, research is being carried out to utilize large quantities of by-products that can be used as alternatives to cement. However, there are problems with reduced strength at early age and retarded setting for major reasons that do not increase the amount of mixture of binders used to replace cement. Thus, in this study, normal cement and high-fineness cement were used and physical properties were reviewed by placing differences in fly ash usage depending on the type of cement. As a result, the characteristics of strength were similar, and the hydration temperature was the same level. Also, the durability test showed that the length change, carbonation resistance were better than those of normal cement. Therefore, it is confirmed that the use of high-fineness cement is effective to reduce the amount of cement used and using more by-products.

Properties of Strength Development of Concrete at Early Age Using High Fineness Cement and Fly Ash (고분말도 시멘트와 플라이애시를 치환한 콘크리트의 조기강도 발현 특성)

  • Ha, Jung-Soo;Kim, Han-Sic;Lee, Young-Do
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.2
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    • pp.154-160
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    • 2018
  • Cement industries are considered key industries for reducing carbon emissions, and efforts are off the ground to reduce the use of cement in the concrete sector. As a part of this effort, research is off the ground to utilize a large amount of industrial by-products that can be used as a substitute for a part of cement. Concrete using industrial by-products has advantages such as durability, environment friendliness and economical efficiency, but there are problems such as retarding and early-age strength deterioration. Therefore, this study aimed to reduce the use of cement and solve the problem of early-age strength deterioration while using fly ash, which is an industrial by-product. Accordingly, it was confirmed that the strength was improved at all ages irrespective of curing temperature by accelerating the hydration reaction by using high fineness cement. Subsequently, high fineness cement was partially replaced with fly ash and the strength development characteristics were examined. As a result, it was possible to exhibit strength equal to or higher than ordinary portland cement even at the early age. Also, it was confirmed that even when the fly ash is replaced by 30%, it is possible to shorten the time for dismantling the forms of vertical and horizontal members.