• 한국구조물진단유지관리공학회 논문집
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• 제10권6호
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• pp.105-113
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• 2006

본 연구는 잔골재와 굵은 골재를 전량 플라이애쉬로 치환한 콘크리트의 공학적 특성을 밝히기 위한 실험적 연구의 결과이다. 그리고 플라이애쉬 전량 치환 콘크리트의 유동성 저하 문제를 추가수량($W_f$)으로 해결하고자 하였다. 실험은 물-시멘트 비($W_c/C$)를 0.35, 0.45 그리고 물-플라이애쉬 비($W_f/FA$)를 0.35, 0.45로 하였다. 플라이애쉬 치환은 P와 Q의 두 가지 방법으로 하였다. P 방법은 플라이애쉬와 첨가수량($W_f$)의 중량이 골재의 중량과 같은 배합법이다[$FA+W_f$ = G (또는 S)]. Q 방법은 플라이애쉬와 골재의 중량이 같고 첨가수량($W_f$)을 추가하는 배합법이다 [$FA+W_f$ > G (또는 S)]. 실험은 굳기 전 콘크리트의 특성과 3, 7, 28 및 91일 압축강도 특성을 측정하였다. 실험결과 압축강도는 $Wc/C=0.35$, $W_f/C=0.35$ 일 때, P 치환법 중에서 잔골재 치환이 다른 배합들보다 향상되었다. Q 방법은 P 방법에 비해 유동성은 향상되었으나, 압축강도는 그렇지 않았다. 실험결과는 잔골재와 굵은 골재를 플라이애쉬로 전량 치환한 콘크리트의 유동성과 강도 특성이 향상됨을 알 수 있었고, 플라이애쉬 치환방법으로 효과적임을 보여주었다.

• 한국구조물진단유지관리공학회 논문집
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• 제11권4호
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• pp.152-158
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• 2007

본 연구는 알칼리 활성시멘트(Alkali Activated Cement)를 콘크리트에 활용하기 위한 기초적인 연구로서 잔골재 및 굵은골재의 혼합비는 일정하게 하고, 활성화제/플라이 애쉬의 혼합비, 그리고 활성화제 중 물유리, 수산화나트륨, 물의 혼합비를 변화시킨 AAC 콘크리트에 대한 압축강도를 측정하였다. 또한 각 변수에 따른 압축강도의 특성을 분석하고, AAC 콘크리트의 최적 혼합비를 구하였다. 그 결과 최대 압축강도 발현을 위한 활성화제 중 물유리, 수산화나트륨, 물의 최적 혼합비는 4.0:1.0:2.5 이었으며, 활성화제/플라이 애쉬의 최적 혼합비는 0.7 이었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 봄 학술발표회 논문집
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• pp.23-28
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• 1991

Silica-Fume, an industrial by product, has an extremely small average partical size of 0.1${\mu}{\textrm}{m}$ and when used as a concrete admixture fills the fine voids which exist in concrete. The purpose of this study is to investigate material properties of the high-strength concrete using Silica-Fume and Fly-Ash. The main variables studied are; a) water-cement ratio. b) Silica-Fume, Fly-Ash content. The maximum compressive strength of 1000Kg/$\textrm{cm}^2$ is achieved with a mix using 18% water-cement ratio, 20% Silica-Fume and 10% Fly-Ash ratio.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.278-284
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• 1997

This study dealt with the flowing properties of the super flowing concrete for class F fly ash producted thermal power plant and the application for concrete industry. For this purpose, fly ash is analyzed for confined water ratio($\beta_p$)and the super flowing concrete is tested the flowing properties including flowing velocity, funneling time, height difference of box test and compressive strength. As the result, in order to satisfy the flowing properties of the super flowing concrete using class F fly ash, the optimum mixing conditions are determined water-bindrer ratio 37$\pm$2%, volume ratio of fine aggregates(Sr) 47$\pm$2% and coarse aggregates(Gv) 51$\pm$1%.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.186-187
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• 2022

The purpose of this study was to give fluidizing properties to non-sirtered cement made using by-products that can replace Portland cement by using a fluidizing agent. Blast furnace slag, C-type fly ash, and F-type fly ash were used for non-sirtered cement, and sand was used for aggregate. The amount of fluidizing agent used was fixed at 1%, and the water-cement ratio (W/C) was different by setting the binder blending ratio of the non-sintered cement differently, and the fluidity test and flow were compared. As a result of the experiment, when the flow standard was 170mm when the fluidizing agent was used, the fluidizing properties were shown at an average water-cement ratio (W/C) of 36%. Through this study, it was confirmed that the fluidizing properties appeared when the fluidizing agent was used in non-sintered cement.

• 자원리싸이클링
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• 제10권5호
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• pp.36-43
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• 2001

The chlorine component in fly ash from municipal solid waste incineration ash was removed by water washing for the purpose of recycling fly ash as a raw material of ordinary portland cement. The samples were a different kind of 리y ashes using $Ca(OH)_2$and NaOH as media of wet scrubber for flue gas cleaning. The content of soluble salts of fly ash using $Ca(OH)_2$and NaOH was 32.8%, 50.1% and the content of chlorine component, 22.9% and 26.0% respectively, which was KCl, NaCl, CaC1OH mainly. When each fly ash was washed using water under conditions of a agitation speed of 300 rpm, a liquid to solid ratio of 10, most soluble salts in fly ash were dissolved within 30 minutes and the content of chlorine component in ash was diminished to the content of 4.4%, 2.O% at $20^{\circ}C$ and 1.7%, 0.8% at $50^{\circ}C$ respectively. And the main compound of residual chlorine component in ash after water washing was friedel`s salt ($3CaO.A1_2$$O_3$.$CaCl_2$.$10H2$O). From analysis results of water quality for wastewater by water washing, the components exceeding discharged wastewater standard were only Pb and Cd. But As pH was controlled to 10 with addition of $CO_2$(g) or $Na_2$$_CO3$in water, the concentration of heavy metals such as Pb and Cd was also under discharged wastewater standard.

• 콘크리트학회논문집
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• 제23권1호
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• pp.99-107
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• 2011

이 연구는 대용량 지상식 LNG 저장탱크에 사용할 고강도 자기충전 콘크리트의 최적배합 조건을 도출하고, 현장적용을 위한 기본 자료를 제안하기 위한 것이다. 60~80 MPa 고강도 자기충전 콘크리트를 적용하면, 벽체두께의 감소와 자기충전성에 따른 인력절감 및 품질확보 등을 통하여 경제성을 확보할 것으로 예상된다. 시멘트 및 분체는 점성 증대 및 수화열 저감에 우수한 플라이애쉬와 저열 시멘트(벨라이트)를 사용하였다. 플라이애쉬의 치환율은 구속수비 및 배합변수 실험을 통해 정하였으며, 배합변수는 단위수량(W), 플라이애쉬 치환율(FA), 물-결합재비(W/B) 및 잔골재율(S/a)로 하여, 최적배합비 및 경제성 평가를 실시하였다. 실험 결과, 설계기준강도 60 MPa의 경우에는 단위수량 165 $kg/m^3$, 플라이애쉬 치환율 20% 및 물-결합재비 27~30%로 나타났으며, 설계기준강도 80 MPa의 경우에는 단위수량 165 $kg/m^3$, 플라이애쉬 치환율 10% 및 물-결합재비 25%로 나타났다. 또한, 기존의 설계기준강도 40 MPa과 비교해 볼 때, 압축강도 증가에 따른 재료비 상승은 60 MPa의 경우 14~22% 및 80 MPa의 경우 33%로 나타나, 현장관리 및 인력절감 등과 함께 매우 경제적인 것으로 나타났다.

• Advances in concrete construction
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• 제11권2호
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• pp.151-161
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• 2021

The major shortcoming of concrete in most of the applications is its high self-weight and thermal conductivity. The emerging trend to overcome these shortcomings is the use of foam-concrete, which is a lightweight concrete consisting of cement, filler, water and a foaming agent. This study aims at the development of a cost-effective high-volume fly-ash foam-concrete insulation wall cladding for existing buildings using natural fiber like rice straw in different proportions. The paper reports the results of systematic studies on various mechanical, acoustic, thermal and durability properties of foam-concrete with and without replacement of cement by fly-ash. Fly-ash replaces 60 percent by weight of cement in foam-concrete. The water-solid ratio of 0.3, the filler ratio of 1:1 by weight, and the density of 1100 kg/㎥ (approx.) are fixed for all the mixes. Rice straw at 1%, 3% and 5% by weight of cement was added to improve the thermal and acoustic efficiency. From the investigations, it was inferred that the strength properties were increased with fly-ash replacement up to 1% rice straw addition. In furtherance, addition of rice straw and fly-ash resulted in improved acoustic and thermal properties.

• 한국건축시공학회지
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• 제7권1호
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• pp.91-98
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• 2007

In this study, the property and plastic cracking pattern of concrete were compared and analyzed with the replacement ratio of fly ash 0, 5, 10, 15, 20% by cement weight. And curing conditions of concrete were given variously such as indoors(with wind speed as 0, 300, 500m/min), outdoors and chamber. The hydration temperature had a tendency to decrease as the replacement ratio of fly ash increased, and in the case of the wind speed 0m/min, it was showed that the moment that the amount of evaporation of water from surface of reference concrete was more than the volume of bleeding was 90 min since casting concrete. The time that the crack initiated had a tendency to be more quickly as the replacement ratio of fly ash increased. The number, length, width and area of crack in the indoor curing, exposed outdoor curing, enclosed outdoor curing had a tendency to decrease as the replacement ratio of fly ash increased. The crack had a tendency to decrease in sequence of exposed outdoor, enclosed outdoor curing, indoors curing. The outbreak of cracking by the change of temperature and humidity was affected by relative humidity more than temperature and the cracking had a tendency to increase as relative humidity lowered.

• 한국지반공학회논문집
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• 제26권1호
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• pp.75-83
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• 2010

저강도고유동화재는 다짐이 필요 없고 유동성이 큰 물질로 일반적으로 시멘트, 비회, 잔골재, 물, 혼화제 등을 혼합하여 만들어진다. 기존의 CLSM은 잔골재로 모래를 사용하고 있으나 때문에 모래가 점점 구하기 어려워지는 현재 우리나라 실정에서는 그대로 사용하기 곤란하다. 본 연구에서는 모래대신 매립회를 이용하여 매립회, 비회, 시멘트, 물의 혼합물로 만들어진 CLSM의 강도특성을 조사하여 사용가능성을 제시하고자 한다. 일축압축강도실험결과 기준 일축압축강도(0.5MPa~1.0MPa)를 만족하는 배합비는 매립회와 비회의 혼합비 0:100~70:30, 시멘트비 3.0~5.0%, 함수비 31~34%로 나타났다. 플로우시험 결과 매립회와 비회를 혼합하여 사용하는 모든 경우(매립회와 비회의 비 30:70~70:30)에서 기준 플로우값(0.2m)를 만족하였다.