• 한국결정성장학회지
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• 제10권1호
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• pp.86-90
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• 2000

석탄회를 환경친화적 건설재로 재활용하기 위한 기초연구로서 미연탄소를 함유한 석탄회와 점토의 복합체에 대해 승온패턴에 따른 소결시험을 실시하여 석탄회의 재활용 가능성을 검토하였다. 소결을 위한 승온조작에서 $20^{\circ}C$/min 이상의 승온속도로 가열함에 따라 2.54 cm 크기의 조골재에서 불균질상이 관찰되었고, 최종 소결온도 $1200^{\circ}C$에서는 가스 팽창에 의한 부풀음(bulging), 내부 기공 및 균열이 발생하였다. 따라서 이에 따른 내부 불균질상을 제거할 수 있는 승온패턴을 제안하여 불균질상을 제거하였다. 최종적으로 얻어진 골재의 압축강도는 최소 요구치인 200kg/$\textrm{cm}^2$에 2.5배가 넘는 670~870kg/$\textrm{cm}^2$이었다.

• 한국구조물진단유지관리공학회 논문집
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• 제2권4호
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• pp.186-193
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• 1998

The purpose of this research is to seek properties of flowing light-weight aggregate concrete and possibility of application. The experimental analysis results by using light-weight aggregate and industrial waste such flyash, furnace slag are as follow. 1) The research shows that flowing light-weight aggregate concrete of slump 23~27cm, slump flow 58~69 cm is possible, but material segregation is appeared above slump 26.5cm and slump flow 65 cm. 2) If mixing ratio of flyash is increase, strength deterioration is about 25 % in early age. It showed that effectiveness of long time strength improvement because strength manifestation ratio is above 95% in a long term. 3) This research showed possibility of substitution of blast furnace slag because strength deterioration by using mixing of furnace slag was appeared small deterioration range as below 10 %. 4) Each experimental compressive strength ratios were 77 %(1st week), 86 %(2nd week), 109 %(8th week), 115 %(13th week), 125 % (26th week) on the basis of 28 days. If mixing ratio of flyash is increase, long term strength increase ratio is improved.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.809-812
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• 1999

This research analyzed the factors for crack generation and proposed the recommended construction methods for the efficient crack control of underground RC box structures under the roadway. The selected main factors were: details of contraction joints, ratio of crack control rebars in longitudinla direction, and placement of flyash concrete. These factors were tested on the actual structures and the significance of each factor was analyzed, The results show that the flyash concrete placement and the inducting minor cracks in a certain direction by adopting contraction joints are practical and efficient methods to control cracks. The significance of crack generating factors increases as the sectional loss of contraction joint spacing increase. It was recommeded that the sectional loss should be higher than 20 percent to maximize the crack generating effects. It was not possible to verify the effect of crack control rebar spacing, but it was estimated that the ratio of crack control rebar should be increased to minimize cracks.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.84-87
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• 1995

Production of high strength concrete requires a low water-cement ratio and this leads to the high cement content. Mineral admixture like fly ash(FA) is often cheaper than ordinary portland cement(OPC) and this factor in combination with possible improvement in workability and moderation of the heat evolution of the cement-rich mixes tends to encourage its use. The other mineral admisture that its use has been widly advocated is silica fume that increases compressive strength due to its pozzolanic reaction. The objective of this study is to assess the contribution of mineral admixtures(FA, SF) to the workability and the strength of concrete with low water-binder ratios. In this experimental study that investigates and analyzes the properties of fresh concrete. it is presented that using admixtures like flyash and silica fume as binding material increases properties of high strength flowing concrete having very low water cementitious ratios of 0.25 and 0.30.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1990년도 봄 학술발표회 논문집
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• pp.29-34
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• 1990

Energy cries and availability have funded extensive research and numerous conferences. So, the idea of adding slags and pozzolans such as flyash to portland cement or portland cement concrete is widely practiced because it helps to reduce cost and conserve energy, resources and the environment. Recently, Silicafume which is the industrial by-product of electric arc furnaces is also widely studied for achieving high strength concrete. It is the aim of this study to provide the fundamental data on the workability and engineering proper of high strength concrete containing flyash and silica fume comparing with plain concrete for the practical use and research data accumulation of a new technique for achieving high strength concrete.

• Structural Engineering and Mechanics
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• 제24권5호
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• pp.585-599
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• 2006

This paper describes a series of laboratory tests carried out to evaluate the influence of bed joint orientation on interlocking grouted stabilised mud-flyash brick masonry under uniaxial cyclic compressive loading. Five cases of loading at $0^{\circ}$, $22.5^{\circ}$, $45^{\circ}$, $67.5^{\circ}$ and $90^{\circ}$ with the bed joints were considered. The brick units and masonry system developed by Prof. S.N. Sinha were used in present investigation. Eighteen specimens of size $500mm{\times}100mm{\times}700mm$ and twenty seven specimens of size $500mm{\times}100mm{\times}500mm$ were tested. The envelope stress-strain curve, common point curve and stability point curve were established for all five cases of loading with respect to bed joints. A general analytical expression is proposed for these curves which fit reasonably well with the experimental data. Also, the stability point curve has been used to define the permissible stress level in the brick masonry.

• 환경위생공학
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• 제14권4호
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• pp.1-8
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• 1999

This study was aimed ultimately to develop an adsorption process treating heavy metal wastewater by utilizing activated carbon using flyash. The affecting factors in adsorption process on heavy metal by flyash adhesion-activated carbon are s follows. Factors such as pH, and quality of activated carbon, and reaction time made batch adsorption isotherm described adsorption capacity was made use of the investigation to evaluate adsorptive possibility of heavy metal.As the results of this study, H ion has influence on adsorption of heavy metal if pH is low. As reaction time is transformed, factors such as optimum reaction time is taken into consideration an adsorptive process of heavy metal because an adsorption and a reduction process occur. Adsorption isotherm of adhesion-activated carbon was generally obeyed to Freundlich formular than Langmuir formular and Freundlich constant, l/n were obtained in the range of 0.1~0.5.

• 콘크리트학회지
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• 제10권1호
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• pp.101-108
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• 1998

시멘트 대체재로 사용하는 플라이애쉬(0, 10 , 30 ,50 %)를 혼입한 콘크리트의강도발현을 관찰하기 위해 각각 21$^{\circ}C$에서 수중양생과 85$^{\circ}C$에서 증기양생방법을 채택하여 실험하였다. 수중양생한 보통 콘크리트는 플라이애쉬 혼입량이 증가할수록 조기재령에서는 낮게 강도발현을 하였으나. 28일 압축강도를 기준으로 하여 물.시멘트비를 변화한 배합비(결합재량 증가)의 실험결과는 조기강도발현이 향상되었다. 특히 플라이애쉬를 30%혼입한 콘크리트는 우수하게 강도발현을 하였다. 그리고 동일한 28일 압축강도를 갖는 배합비(결합재량 증가)에서 증기양생한 플라이애쉬콘크리트는 보통콘크리트보다 강도발현이 비슷하거나 향상되었으며, 양생온도는 플라이애쉬콘크리트의 강도발현에 많은 영향을 미치는 것으로 관찰되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.205-206
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• 2010

본 연구는 인공경량콘크리트와 보통콘크리트의 마모저항성에 대한 실험이다. 동일조건에서는 인공경량콘크리트의 마모손실률이 물-결합재비가 커짐에 따라 더욱 증가하지만 플라이애쉬를 혼입한 경우 마모손실률의 차이는 감소하며 물-결합재 30%와 플라이애쉬 15%인 경우 인공경량콘크리트와 보통콘크리트의 마모손실률의 차이는 약 3%정도로 거의 발생하지 않았다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.1051-1056
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• 2000

There were various study about an early compressive strength of concrete. But, they had a problems-likes accuracy and spending too much necessary time. The purpose of this study is develope method that suitable for each field proportioning. The result of this study are as follows : 1) The standard deviation between flyash added concrete's accelerated strength and it's standard compressive strength is follows, 10% in accelerated strength, 4.5% in 28-days strength, 10% in accelerated strength of S/A changed concrete, 2.3% in 28-days strength. 2) When flyash added into concrete, coefficient of determination between accelerated strength and 7-days strength is 0.63%, 0.89 between accelerated strength and 28-days strength. When S/A is changed, coefficient of determination is 0.77, 0.91.