• Title/Summary/Keyword: 포졸란 반응

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Flexural Behavior of Hwangtoh Concrete Beams with Recycled PET Fiber (재생 PET섬유가 혼입된 황토 콘크리트 보의 휨 거동)

  • Kim, Sung-Bae;Nam, Jin-Won;Yi, Na-Hyun;Kim, Jang-Jay-Ho;Choi, Hong-Shik
    • Journal of the Korea Concrete Institute
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    • v.20 no.5
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    • pp.619-626
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    • 2008
  • There have been numerous studies to develop eco-friendly concrete. The attempt to reduce the amount of cement usage is suggested as one of the solutions for eco-friendly concrete. To reduce the amount of cement usage, the pozzolan-reaction materials such as ground granulated blast furnace slag, fly ash, and meta kaolin are widely used as the mineral admixture. Hwangtoh which deposited broadly in Korea is a well known eco-friendly material and the activated Hwangtoh with pozzolan-reaction can be practically used as a mineral admixture of concrete. Meanwhile, PET fiber made of recycled PET bottle is a type of recycled material, which can be used to control micro cracks in concrete. But the study about concrete mixed with recycled PET fiber is insufficient and the research of Hwangtoh concrete mixed with PET fiber is urgently needed presently. In this study, experiment and analysis flexural behavior of Hwangtoh concrete blended with recycled PET fiber are carried out. The results are discussed in detail.

A Study on the Diffusion of Ions in Hardened Blended Cement (혼합시멘트 경화체에서의 이온확산에 관한 연구)

  • 방완근;이승헌;김창은
    • Journal of the Korean Ceramic Society
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    • v.36 no.3
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    • pp.260-265
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    • 1999
  • 보통 포틀랜드 시멘트와 플라이애쉬, 슬래그를 혼합한 혼합시멘트 경화체를 이용하여 이온 확산에 미치는 혼합재의 영향과 양이온 공존시 염소이온의 확산에 대하여 고찰하였다. 겉보기 이온확산계수가 보통 포틀랜드의 시멘트보다 플라이애쉬와 슬래그를 혼합한 시멘트 경화체가 약 10-3배로 매우 낮은 값을 나타내었다. 이것은 포졸란 반응에 의해 많은 CSH 수화물이 capillary pore에 형성되어 macro pore가 감소되고 micro pore가 증가되어 이온 확산에 대한 저항이 커졌기 때문이다. 또한, Mg2+이온 공존시에 염소이온의 확산은 증가되었다.

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The Research on Possibility as Mineral Admixture of Agriculture by-product (농업부산물의 혼화재료로써 사용가능성에 관한 연구)

  • Jeong, Euy-Chang
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.05a
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    • pp.178-179
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    • 2019
  • The purpose of this study was to investigate the possibility as mineral admixture of agriculture by-product. XRD and XRF analysis were performed on rice straw ashes at various combustion temperatures to identify chemical compositions. Also to evaluate properties of pozzolanic reaction, pH change method was tested.

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Expansion Properties of Mortar Using Waste Glass and Industrial By-Products (폐유리와 산업부산물을 사용한 모르터의 팽창특성)

  • 박승범;이봉춘
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.440-448
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    • 2002
  • Waste glass has been increased with the development of industry. The utilization of waste glass for concrete can cause the concrete to be cracked and to be weakened due to an expansion by alkali-silica reaction(ASR). In this study, ASR expansion and properties of strength were analyzed in terms of waste glass color(amber, emerald-green), industrial by-products(ground granulated blast-furnace slag, fly ash), and the content of industrial by-products for reducing ASR expansion caused by the waste glass. The possibility of using glass ground as pozzolanic properties was also analyzed. From the result of this study, the pessimum size of waste glass was 2.5∼1.2 mm regardless of waste glass color. And the smaller than 2.5∼1.2 mm waste glass is, the more decreasing expansion of ASR is. Also, the combination of waste glass with industrial by-products have an effect on reducing the expansion and strength loss caused by ASR between the alkali in the cement paste and the silica in the waste glass, and the glass ground of less than 0.075 mm is applicable as a pozzolanic material.

Effect of Waste Glass Wool on Mechanical Properties of Concrete (폐글라스울이 콘크리트의 역학적 특성에 미치는 영향)

  • Kim, Jeong-Tae;Choi, Woo-Hyuk;Chung, Chul-Woo;Lee, Jae-Yong
    • Journal of the Korea Institute of Building Construction
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    • v.16 no.2
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    • pp.117-123
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    • 2016
  • Glass wool is a material that has been used as a heat insulator in various fields including construction industry. Since it is a nonflammable material, it does not generate toxic gases on fire, and thus public agencies recommend using glass wool as a heat insulator instead of other organic materials. However, repeated drying and wetting cycles can deteriorate thermal property of glass wool due to the shrinkage and reduction in pore size. For this reason, it needs to be replaced periodically, and waste materials are generated. This research aims to utilize waste glass wool as additives for increasing mechanical properties of concrete. According to the experimental results, it was found that glass wool has weak pozzolanic activity, and beneficial effect on both compressive and flexural strength. The optimum amount found in this experimental work was 0.5% volumetric addition to the concrete.

An Analysis on the Properties of Concrete Used as the Mixture Material with Carbon Black (카본블랙을 혼화재료로 사용한 콘크리트의 특성 분석)

  • Ryu, Hyun-Gi;Kwon, Yong-Ju
    • Journal of the Korea Institute of Building Construction
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    • v.10 no.2
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    • pp.59-66
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    • 2010
  • The purpose of this study is to determine the possibilities of blending carbon black, which is known for its permeability as well as its strong heat and fire resistance, into concrete, in a manner that reinforces its strengths mentioned above. Experiments show that in non-solidified, fresh-mixed concrete, the addition of carbon black effectively reduced slump level and air content due to its absorptiveness and minute particle size. It also showed good results in terms of coagulation time, penetration resistance and bleeding level. In solid concrete, it showed better strength than plain concrete. Due to the pozzolanic reaction, its strength became more pronounced over time. At approximately 850 degrees Celsius, the heat and fire resistance level increased in parallel to the level of chemical substitution (by carbon black). Drying shrinkage level appeared to be optimal, and environmental assessment test results related to CO, CO2 and formaldehyde also scored better than plain concrete. In summary, with the appropriate use of AE water-reducing agents, carbon black can prove to be a strong candidate as an ingredient for industry-grade concrete.

Studies on the Properties of High Performance and High Strength Cement Mortar Using Meta Kaolin and Silica Fume (Meta Kaolin 및 Silica Fume을 이용한 고성능 고강도 시멘트 모르타르 특성에 관한 연구)

  • 정민철
    • Journal of the Korean Ceramic Society
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    • v.33 no.5
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    • pp.519-523
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    • 1996
  • Calcium hydroxide produced by cement hydration decreases the durability and the compressive strength of cement mortars. Pozzolanic property of meta kaolin and silica fume allows to avoid this drawback. Calcium hydroxide consumption according to pozzolanic raction is evaluated by Fourier differential thermal analysis. Particulary the properties of high performance and high strength of cement mortar containing above 10% meta kaolin and silica fume were resulted in the pozzolanic activity.

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Properties of Eco-Construction Material Using Recycled Sewage Sludge Ash (하수슬러지 소각재를 재활용한 친환경 건설 소재의 재료적 특성)

  • Jo, Byung-Wan;Lee, Jea-Ik;Park, Seung-Kook;Lee, Jae-Seung
    • Journal of the Korea Concrete Institute
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    • v.19 no.6
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    • pp.667-676
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    • 2007
  • As the 21st century began, cement and concrete that are representatives of modem building materials became a major factor in global warming, air pollution and environmental pollution. Also, the problems that are generated while pursuing high performance and high strength became social issues. Therefore, it has become urgent to prepare counter plans. This study has aimed at the recycling of sewage sludge ash and developing it as a new concept in building material which serves the environmental considerations for long-lasting developmental purpose. Also, the study aimed to find a substitute for scarce natural resources and to secure high techniques for waste recycling. The purpose of this study was also to solve fundamentally secondary environmental pollution. The results revealed that the chemical components of sewage sludge ash are mainly $SiO_2\;and\;Al_2O_3$ which are similar to the components of pozzolan. Also, it was identified that sewage sludge ash can be utilized as a hardened specimen with an alkali activated pozzolan reaction. Considering the possibility of appropriate strength development and the advantage of drying shrinkage, compared with that of cement, it was believed that sewage sludge ash can demonstrate a function as a substitute for cement given.

A Sustainable and Viable Method to Recycle Oyster Shell Waste as an Alternative of Limestone in Limestone Calcined Clay Cement (LC3) (석회석 소성 점토 시멘트(LC3) 내 석회석 대체재로서 굴 패각의 친환경적인 재활용 방안)

  • Her, Sung-Wun;Suh, Heong-Won;Park, Jae-Yeon;Im, Su-Min;Bae, Sung-Chul
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.2
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    • pp.219-226
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    • 2020
  • Over the last decades, great efforts have been devoted to reuse industrial wastes and by-products from various industries as supplementary cementitious materials in order to reduce carbon dioxide(CO2) emission by reducing the use of Portland cement in construction. Oyster shell waste, originating from the fishery industry, is available in huge quantities in certain areas, and is generally discarded or landfilled. In this study, we aimed to reuse oyster shell as an alternative to limestone in limestone calcined clay cement(LC3). The oyster shell calcined clay cement(OC3) paste were produced and were characterized via X-ray diffraction, isothermal calorimetry, compressive strength tests, and thermogravimetry. The results revealed that OC3 pastes exhibited similar strength development and reactivities by pozzolanic reaction with LC3, which implies that oyster shell could be used as a substitute for limestone in LC3.

Durability of the Solidified Mine Tailing-Hydrated Lime Mixture Against Repeated Freezing and Thawing (폐광미-소석회 고화체의 동결융해 내구성에 관한 연구)

  • Min, Kyoung-Won;Lee, Hyun-Cheol;Kim, Tae-Poong
    • Journal of Industrial Technology
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    • v.28 no.B
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    • pp.65-69
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    • 2008
  • The tailings piled in abandoned mines are well-known potential sources of soil contamination. Hydrated limes were applied as cementing materials to solidify heavy metal contaminated tailings for the purpose of reducing their toxicity and migration rates. The optimum mixing ratio of tailings, hydrated lime, and water was determined through a preliminary test. The mixtures of mine tailings and hydrated lime solidified through pozzolanic reaction were tested for their durability against repeated freezing and thawing processes. After repeated freezing and thawing, the uniaxial compressive strengths of all the solidified mixture specimens decreased in comparison with those before test but still higher than $3.5kgf/cm^2$, the standard recommended for land reclamation solids by EPA(Environmental Protection Agency), which suggested that hydrated lime be a potential material to treat the abandoned mine tailings for the environmental purpose.

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