• Title/Summary/Keyword: 석회석 미분말

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Chloride Ion Penetration Properties of Normal Strength High-Fluidity Concrete Using Lime Stone Powder (석회석 미분말을 활용한 보통강도 고유동 콘크리트의 염소이온 침투특성)

  • Choi, Yun-Wang;Moon, Jae-Heum;Eom, Joo-Han
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.4
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    • pp.160-168
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    • 2010
  • Recently, there are a lot of researches related to the high-fluidity concrete (HFC) with field applications. However, most applications and studies are with concretes with high strength level so there are little studies about durability evaluations such as chloride ion penetration properties with normal strength concrete. Therefore, to evaluate the durability of HFC with normal strength level, this study performed the chloride ion penetration test and observed the micro pore distribution with normal strength HFC which contains limestone powder. Experimental results showed that most micro-pores have diameters between 0.005 to 0.05 ${\mu}m$ with HFCs using limestone powder and the average diameter becomes larger with the increase of limestone powder content. Also, it was shown that, with the increase of the limestone powder content, penetration depth and diffusion coefficient of chloride ion increased and diffusion coefficient had good relationships with compressive strength and average pore diameter with the coefficient of determination over 0.90.

The Effect of Limestone Powder Admixture Chemical Properties on Workability and Compressive Strength of Composite Cement (석회석 미분말 혼합재의 화학특성이 혼합시멘트 유동성과 강도에 미치는 영향)

  • Suh, Dong Kyun;You, Byeong Know;Choi, Jae Won;Kim, Kyeong Suk;Woo, Ji Wan
    • Cement Symposium
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    • s.49
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    • pp.29-30
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    • 2022
  • Since the climate problem getting severe, carbon neutrality is rising global issue. The limestone powder addition that can substitute clinker in cement is look forward to get positive effect as filler. This study focus on the effect of limestone powder chemical characteristic on mortar workability and compressive strength. Consequently, regardless of type of limestone and subsitution amount, the compressive strength was lower then OPC. But the workability of limestone composite cement showed higher then OPC. Considering latter strength development, using unit water decreasing effect of limestone composite cement is planned further.

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A Study of Chloride Diffusion Coefficient and Microstructure of High Fluidity Concrete Using Limestone Powder (석회석 미분말을 활용한 고유동 콘크리트의 염소이온 확산계수와 미세공극에 관한 연구)

  • Choi, Yun-Wang;Jeong, Jae-Gwon;Kim, Kyung-Hwan;Ha, Sang-Woo;Ryu, Deuk-Hyun;Oh, Sung-Rok
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.199-200
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    • 2010
  • This paper was estimated the diffusion coefficient through the chlorine ion diffusion coefficient of the high fluidity concrete using the limestone powder. Also, the micro void of high fluidity concrete examined according to the mixing ratio of the limestone powder by the mercury intrusion porosimetry.

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An Experimental Study on the Rheological Properties of the Combined Self-Compacting Concrete by Quality Variations (품질변동에 따른 병용계 자기충전 콘크리트의 유동특성에 관한 실험적 연구)

  • Kwon, Yeong-Ho
    • Journal of the Korea Concrete Institute
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    • v.26 no.3
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    • pp.277-285
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    • 2014
  • The purpose of this study is to investigate experimentally the variation factors range having influence on the rheological properties of the combined self-compacting concrete according to materials quality, weighting error and site conditions. Two types cement (blast-furnace slag cement and belite cement), lime stone powder as binder and the optimum mix proportions in the preceded study are selected for this study. Also, variations for sensitivity test are as followings; (1) Concrete temperature 3 cases (2) Surface moisture of sand 5cases (3) Fineness modulus of sand 5cases (4) Specific surface of lime stone powder 3cases (5) Dosage of chemical admixture 5cases. Slump flow ($650{\pm}50mm$), 500 mm reaching time (($7{\pm}3sec$), V-type flowing time ($15{\pm}5sec$) and U-box height (min. 300 mm) are tested for sensitivity. As test results, the variations range for quality control are as followings. (1) Concrete temperature; $10{\sim}20^{\circ}C$(below $30^{\circ}C$) (2) Surface moisture of sand; $base{\pm}0.6%$ (3) Fineness modulus of sand; $2.6{\pm}0.2$ (4) Dosage of chemical admixture; $base{\pm}0.2%$ (5) Specific surface of lime stone powder $6000cm^2/g$. Compared with two types cement including based belite cement (binary type) and based slag cement (ternary type), the combined self-compacting concrete used belite cement type is most stable in the quality control because of high contents for lime stone powder and $C_2S$. It is to propose a control scheme of the combined self-compacting concrete in the actual construction work.

Material Properties of Concrete Produced with Limestone Blended Cement (석회석 혼합 시멘트로 제조된 콘크리트의 기초 물성)

  • Bang, Jin-Wook;Kwon, Seung-Jun;Shin, Kyung-Joon;Chung, Woo-Jung;Kim, Yun-Yong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.2
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    • pp.125-132
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    • 2015
  • This paper presents an experimental investigation in order to evaluate fresh and hardened properties of LP (Limestone Powder) blended cement concrete. The cement contents of the mixtures are replaced by LP in the range of 10%, 15%, 25%, and 35%, while a control mixture is prepared with only OPC (Ordinary Portland Cement). The fresh concrete properties like slump and air content are similar to those of control mixture up to 35% of replacement ratio of LP, however a delay in setting time is evaluated. The hardened properties including compressive strength, flexural strength, and rapid freezing and thawing resistance shows similar results of control mixture up to 15% of replacement. Relatively lower strength development is evaluated over 25% replacement of LP. For accelerated carbonation test, resistance to carbonation rapidly decreases with increasing LP replacement ratio due to the limited amount of $Ca(OH)_2$. From the study, LP replacement under 15% can be adopted considering reduction of strength and resistance to carbonation.

Characteristic on Autogenous Shrinkage of High Fluidity Concrete Using Limestone Powder (석회석 미분말을 활용한 고유동 콘크리트의 자기수축 특성)

  • Choi, Yun-Wang;Jeong, Jae-Gwon;Moon, Jae-Heum;Moon, Dae-Joong;Park, Man-Seok;Choi, Byung-Keol
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.385-386
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    • 2010
  • This paper was examined the autogenous shrinkage properties through the fludity properties and autogenous shrinkage volume of high fluidity concrete using limestone powder.

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Design of Fiber Reinforced Cement Matrix Composite Produced with Limestone Powder and Flexural Performance of Structural Members (석회석 미분말을 혼입한 시멘트계 매트릭스 섬유복합재료의 설계 및 구조부재의 휨성능)

  • Hyun, Jung-Hwan;Kim, Yun-Yong
    • Composites Research
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    • v.29 no.6
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    • pp.328-335
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    • 2016
  • The purpose of this study is to develop fiber reinforced cement matrix composite (ECC) produced with limestone powder in order to achieve high ductility of the composite, and to evaluate flexural performance of structural members made with ECC. Four kinds of mixture proportions were determined on the basis of the micromechanics and a steady state cracking theory considering the matrix fracture toughness and fiber-matrix interfacial characteristics. The mechanical properties of ECC, represented by strain-hardening behavior in uniaxial tension, were investigated. Also, strength property of the composite was experimentally evaluated. Two structural members made with ECC were produced and tested. Test results were compared with those of conventional concrete structural members. Increased limestone powder contents of ECC provides higher ductility of the composites while generally resulting in a lower strength property. ECC structural members exhibited higher flexural ductility, higher flexural load-carrying capacity and tighter crack width compared to conventional structural members.

A Study on the Quality Properties of Exposed High Fluidity Concrete using Fly Ash and Limestone Powder (플라이애시 및 석회석 미분말을 사용한 고유동 노출 콘크리트의 품질특성에 관한 연구)

  • Choi, Yun-Wang;Oh, Sung-Rok;Kim, Ji-Hoon;Kim, Kyung-Hwan
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.1 no.1
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    • pp.67-75
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    • 2013
  • Recently, the interest is increasing about the exposed concrete, accordingly, exposed concrete is expanding the use. However, concrete structures is difficult to apply the general concrete for exposed concrete, due to complex section and compact reinforcement, increasingly. Therefore, in this paper, for application of high fluidity concrete as exposed concrete, exposed high fluidity concrete using fly ash and lime stone powder was manufactured and observed quality property(fluidity properties, mechanical properties and Surface Properties) of exposed high fluidity concrete. The experiments are based on the OPC and LSP10, was evaluated Impact on the quality of concrete according to mixing ratio of FA(0, 10, 15 and 20). As a result, fluidity properties, mechanical properties and Surface Properties of exposed high fluidity concrete were satisfied to requirement conditions, fluidity and surface finishability was improved depending on mix of fly ash and limestone powder. Through this, we utilize of basic research data for development of high fluidity concrete for exposed concrete.

A Study on the Strength Properties of Green Mortar Using Limestone Powder (석회석(石灰石) 미분말(微粉末)을 이용(利用)한 그린모르타르의 강도(强度) 특성(特性)에 관한 연구(硏究))

  • Jo, Byung-Wan;Choi, Ji-Sun;Kim, Kyung-Tae
    • Resources Recycling
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    • v.22 no.3
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    • pp.36-42
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    • 2013
  • According to the recent community-based structures enlargement, specification, and diversification. It needs appropriate construction materials in terms of intensity and environmental aspects. Thus, in manufacturing the cement using micro limestone powder which is main material. It is also expected to save energies and reduces $CO_2$, by using the blast furnace slag and fly ash which are mitigated environmental load construction materials that emerged. In this research, The durability aspect tries to be grasped considering the chemical property according to the coherence of the hydration product. Consequently, The compressive strength was measured over 30 Mpa on 3rd. In addition, according to the content of the limestone powder, the setting time is promoted. It has the feature expanded in the length change. And it is determined because the possibility of replacing the existing for construction material such as it is measured compared with the time to use the portland cement usually that flexural strength is high with the age 7 days ago, so it is sufficient.