• 제목/요약/키워드: fly ash

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Improvement of bond strength and durability of concrete incorporating high volumes of class F fly ash

  • Wu, Chung-Hao;Chen, Chien-Jung;Lin, Yu-Feng;Lin, Shu-Ken
    • Advances in concrete construction
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    • 제12권5호
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    • pp.367-375
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    • 2021
  • This study experimentally investigated the improvement of bond strength and durability of concrete containing high volume fly ash. Concrete mixtures made with 0%, 25% and 60% replacement of cement with class F fly ash were prepared. Water-binder ratios ranged from 0.28 to 0.72. The compressive, flexural and pullout bond strength, the resistance to chloride-ion penetration, and the water permeability of concrete were measured and presented. Test results indicate that except for the concretes at early ages, the mechanical properties, bond strength, and the durability-related chloride-ion permeability and water permeability of concrete containing high volume (60% cement replacement) fly ash were obviously superior to the concrete without fly ash at later ages of beyond 56 days. The enhanced bond strength for the high volume fly-ash concrete either with or without steel confinement is a significant finding which might be valuable for the structural application.

물리적으로 활성화된 플라이애쉬를 함유한 시멘트 및 복합체의 이산화탄소 배출량 평가 (Strength-based Evaluation of CO2 Emission for Cement and Composite Containing Mechanically Sctivated Fly Ash)

  • 순양;이한승
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2021년도 봄 학술논문 발표대회
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    • pp.125-126
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    • 2021
  • Fly ash, has been widely used as one of the main supplementary cementitious materials (SCMs) in the world, to replace part of cement to significantly save energy and reduce greenhouse emission. Via mechanical activation, fly ash can replace more cement without impairing early age compressive strength. This study focuses on the strength-based evaluation of carbon dioxide emission for blended cement composite containing mechanically activated fly ash. Results indicate that under similar compressive strength, a prominent drop has been witnessed in embodied energy of binary cement and CO2 emission of the composite containing mechanically activated fly ash compared with those containing ordinary fly ash.

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대나무 재를 혼합한 플라이에쉬 지오폴리머 콘크리트의 물리적 특성에 대한연구 (Mechanical Properties of Fly Ash Geopolymer Concrete Incorporating Bamboo Ash)

  • 샤픽빈이신크;이한승
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2019년도 추계 학술논문 발표대회
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    • pp.33-34
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    • 2019
  • Malaysia, as a tropical rainforest country, enjoys an abundance of bamboo plant that proliferate throughout the country. The application of geopolymer technology has become a trend and preserve the environment from harm. Fly ash geopolymer concrete has low early strength and requires 24 hours for the concrete to harden. Thus, the presence of calcium and potassium content in bamboo ash could remedy this problem. Besides, there is no research regarding the use of bamboo ash as a binder in geopolymer concrete. Therefore, the presence of bamboo ash could improve the research field with the use of agriculture waste in a building construction. This research aim is to use bamboo ash in the production of fly ash geopolymer concrete. The specimens were casted in $100mm{\times}100mm{\times}100mm$ cubes and sodium based activator were used as the alkaline solutions. The binders are formulated with different binder ratio. All test specimens were cured at ambient temperature ($23^{\circ}C-25^{\circ}C$) and 100% fly ash was chosen as control specimen. To determine the mechanical properties of fly sh geopolymer concrete with the presence of bamboo ash, compressive strength test was conducted. The test results depicted that as the percentage of bamboo ash decreases, compressive strength increases. Also, the addition of 5% of bamboo ash into fly ash geopolymer concrete could improve the early strength in 7 days. The results were proven with the result explained by X-ray fluorescence (XRF) and X-ray diffraction (XRD). Therefore, it can be concluded that the addition of bamboo ash improved the properties of fly ash geopolymer concrete at early ages.

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CaO 화합물이 다량 함유된 비산재의 수화 특성에 관한 연구 (Hydration Characteristics of Coal-Fly Ash Containing High CaO Compound)

  • 심준수;이기강;김유택;강승구
    • 한국세라믹학회지
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    • 제49권2호
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    • pp.185-190
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    • 2012
  • The purpose of this study was to examine a possibility that fly ash could be used as raw material for carbonation by conducting the experiment on magnetic separation and hydration of fly ash that contained a large amount of CaO composite. Wet magnetic separation experiment was performed to remove the component of magnetic substance that contained fly ash, which aimed at increasing the content of CaO in the non-magnetic domain. The selected fly ash was used for hydration experiment before the TG-DTA, XRF and XRD analyses were made to confirm the Ca component that could be carbonated. Then, the fly ash was turned to a hydrate that was favorable to dissociation of $Ca^{2+}$ ion. As a result, the magnetic separation enabled detecting the content of CaO component by up to 61 wt% in the non-magnetic domain. Since the hydrate was confirmed, it is believed that the fly ash can be used as raw material for carbonation.

플라이애쉬를 대량 사용한 고강도 콘크리트에 관한 실험적 연구 (The Experimental Study on High Strength Concrete of High Volume Fly-Ash)

  • 이동하;서동훈;전판근;백민수;임남기;정상진
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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    • pp.275-280
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    • 2002
  • To study of high volume fly -ash concrete replace cement and fine aggregate together. Proportion consideration economy cost and performance improve replacement high volume fly-ash. Experimentation study of high-strength which cement about fly-ash replacement maximum 50%Flash concrete tested slump, air contest, setting and Hardening concrete tested day of age 1, 3, 7, 28, 91 compression strength in underwater curing. Purpose of study is consultation materials in field that variety of fly ash replacement concrete mix proportion comparison and valuation.

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플라이애쉬와 실리카흄을 사용한 재생골재 콘크리트의 공학적 특성 (The Engineering Properties of Recycled Aggregate Concrete using Silica-Fume and Fly-Ash)

  • 구봉근;이상근;신재인;이현석
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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    • pp.229-232
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    • 1999
  • This study provided the engineering properties of the recycled aggregate concrete with fly-ash and silica-fume. There are considered recycled aggregate substitution ratio, and fly-ash silica-fume mix ratio as the experimental variable. From the experimental result, we could know that the recycled aggregate concrete mixed silica-fume is superior on the compressive strength but, is poor on the construction property than fly-ash. The optimal mix ratio of the fly-ash and silica-fume is 10% in all.

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High Volume 플라이애쉬 콘크리트의 내구적 특성 연구 (A Study on the Properties of High Volume FlyAsh Concrete)

  • 이진용;손해원;최수홍;정은경;조현수
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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    • pp.203-206
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    • 1999
  • An experimental study is carried out to investigate the characteristics of concrete containing high volume fly ash. The compressive and tensile strength of fly ash concrete is slightly lower than those of ordinary concrete between 7and 28 days, however, the long-term compressive strength is significantly higher at 180 days. In durability, the high volume fly ash concretes are generally higher resistance of freeze and thaw and lowe chloride penetration, however, the depth of carbonation is increased with increasing fly ash content.

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주물공장에서 배출되는 플라이애시를 이용한 콘크리트의 특성에 관한 실험적 연구 (I) (An Experimental Study on the Characteristics of Concrete using Casting Foundry Fly Ash (I))

  • 진치섭;엄장섭;이홍주;김희성;정달영;신동익;이영호
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1994년도 가을 학술발표회 논문집
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    • pp.240-247
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    • 1994
  • The purpose of this study is to examine the raising of strength of concrete and workability using casting foundry fly ash. First, we conducted analysis of chemical components of fly ash. Then, we tested uniaxial strength of concrete at ages of 3, 7, and 28 days. As a result, we found that the strength of concrete using casting foundry fly ash is raisen up 16% than plain concrete when the fly ash is added 0.6% of weight of cement.

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Fly ash를 이용한 기상의 세슘포집성 분석

  • 신진명;박장진;전관식;김연구;김종호
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1995년도 추계학술발표회논문집(2)
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    • pp.812-817
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    • 1995
  • 세슘의 고정화재료로서 Si/Al의 몰비가 약 2인 석탄화력발전소 산업폐기물인 fly ash와 CsNO$_3$의 반응이 열중량 분석기, 시차 열분석기 및 X-ray 회절분석기를 이용하여 공기분위기에서 수행되었다. X-ray 회절 분석결과 fly ash는 mullite와 quartz로 되어 있었고, fly ash와 세슘과의 반응물인 pollucite(CsAlSi$_2$O$_{6}$)의 생성이 확인되었다. 따라서 기상의 세슘화합물을 효과적으로 제거하기 위한 포집제의 원료물질로서 fly ash의 이용 가능성을 확인하였다.

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플라이 애시 혼합 시멘트 페이스트의 유동성 평가 (Evaluation of the Fluidity of Fly Ash Cement Paste)

  • 이승헌;김홍주;판정열;대문정
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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    • pp.1221-1226
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    • 2000
  • Influence of characters of fly ash on the fluidity of cement paste with polycarboxylic acid type superplasticizer has been investigated in connection with the particle size of distribution, unburned carbon content, specific surface area and shape of fly ash. The fluidity of paste is increased with increasing roundness of fly ash and it is decreased with increasing n-value of Rosin-Rammler distribution function. There is a linear correlation between roundness/n-value and fluidity of fly ash cement paste.