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Title |
To evaluate the effects of limestone powder and silica fume on the properties of high-strength high-volume ground
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Authors |
정지용(Ji-Yong Jeong) ; 장승엽(Seung-Yup Jang) ; 최영철(Young-Cheol Choi) ; 정상화(Sang-Hwa Jung) ; 김성일(Sung-Il Kim) |
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DOI |
http://dx.doi.org/10.4334/JKCI.2015.27.2.127 |
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Keywords |
고로슬래그 미분말 ; 고강도 ; 석회석 미분말 ; 실리카퓸 ; 수화반응 ; 포졸란 반응 ground granulated blast-furnace slag(GGBFS) ; high strength ; limestone powder ; silica fume ; hydration ; pozzolanic reaction |
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Abstract |
granulated blast-furnace slag (GGBFS) blended cement concrete, this study investigated the rheology, strength development, hydration and pozzolanic reaction characteristics, porosity and pore size distribution of high-strength mortars with the water-tobinder ratio of 20, 50 to 80% GGBFS, up to 20% limestone powder, and up to 10% silica fume. According to test results, compared with the Portland cement mixture, the high-volume GGBFS mixture had much higher flow due to the low surface friction of GGBFS particles and higher strength in the early age due to the accelerated cement hydration by increase of free water; however, because of too low water-to-binder ratio and cement content, and lack of calcium hydroxide content, the pozzolanic reactio cannot be activated and the long-term strength development was limited. Limestone powder did not affect the flowability, and also accelerate the early cement hydration. However, because its effect on the acceleration of cement hydration is not greater than that of GGBFS, and it does not have hydraulic reactivity unlikely to GGBFS, compressive strength was reduced proportional to the replacement ratio of limestone powder. Also, silica fume and very fine GGBFS lowered flow and strength by absorbing more free water required for cement hydration. Capillary porosities of GGBFS blended mortars were smaller than that of OPC mortar, but the effect of limestone powder on porosity was not noticeable, and silica fume increased porosity due to low degree of hydration. Nevertheless, it is confirmed that the addition of GGBFS and silica fume increases fine pores.
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