• Title/Summary/Keyword: 시멘트계

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The Fundamental Characteristics for Mix Proportion of Multi-Component Cement (배합비에 따른 다성분계 시멘트의 기초특성)

  • Kim, Tae-Wan;Jeon, Jae-Woo;Seo, Min-A;Jo, Hyeon-Hyeong;Bae, Su-Yeon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.3
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    • pp.66-74
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    • 2016
  • The aim of this research work is to investigate the mix proportion of multi-component cement incorporating ground granulated blast furnace(GGBFS), fly ash(FA) and silica fume(SF) as an addition to cement in ternary and quaternary combinations. The water-binder ratio was 0.45. In this study, 50% and 60% replacement ratios of mineral admixture to OPC was used, while series of combination of 20~40% GGBFS, 5~35% FA and 0~15% SF binder were used for fundamental characteristics tests. This study concern the GGBFS/FA ratio and SF contents of multi-component cement including the compressive strength, water absorptions, ultrasonic pulse velocity(UPV), drying shrinkage and X-ray diffraction(XRD) analysises. The results show that the addition of SF can reduce the water absorption and increase the compressive strength, UPV and drying shrinkage. These developments in the compressive strength, UPV and water absorption can be attributed to the fact that increase in the SF content tends basically to consume the calcium hydroxide crystals released from the hydration process leading to the formation of further CSH(calcium silicate hydrate). The strength, water absorption and UPV increases with an increase in GGBFS/FA ratios for a each SF contents. The relationship between GGBFS/FA ratios and compressive strength, water absorption, UPV is close to linear. It was found that the GGBFS/FA ratio and SF contents is the key factor governing the fundamental properties of multi-component cement.

Shrinkage Characteristic of Cementitious Composite Materials for Additive Manufacturing (적층공법을 적용한 시멘트계 복합재료의 수축특성)

  • Lee, Hojae;Kim, Ki-Hoon;Yoo, Byeong-Hyun;Kim, Won-Woo;Moon, Jae-Heum
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.6
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    • pp.99-104
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    • 2019
  • In the present study is focused on the evaluation of the shrinkage characteristics of mix proportion using viscosity agent for printing. Also, another purpose is to compare the shrinkage properties of the mold cast specimen with the additive manufactured specimen using 3D printing techniques. Viscosity agent makes the shrinkage was reduced by an average of 25% (as of 56 days) compared to the reference mix. The effects of reduced shrinkage were also founded, with a reduction of about 15% (as of 28 days).As a result of evaluating the shrinkage using the additive manufactured specimen and the mold cast specimen prepared by the printing mix, the shrinkage of the additive manufactured specimen was reduced by about 25% (based on 28 days). Based on the results of this study, it is possible to predict the shrinkage rate and the occurrence of cracks due to shrinkage on the printing of cement-based composite materials using 3D printing.