• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.55-62
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• 2000

In this paper, a laboratory investigation was carried out to estimate the strength improvement of quicklime mixture with fly ash and rice husk ash for the effective use of surplus soils, and the shear strength with curing time was estimated at lime 10 percent with the change of fly ash and rice husk ash content. The effect of strength improvement has been established through the change of fly ash and rice husk ash content from the samples taken at Samsan region, Ulsan. The test results indicated that the presence of lime with fly ash and rice husk ash encouraged the stabilization efficiency of lime with fly ash and rice husk ash, and increased shear strength. Furthermore, it is necessary for inquiring into the relationship between the characteristics of strength and the chemical components.

• 콘크리트학회논문집
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• 제16권6호
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• pp.751-757
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• 2004

화력 발전소에서 발생하는 석탄회(fly ash, bottom ash)를 안정적으로 재활용하기 위하여 알칼리 활성화된 석탄회 경화체 및 인공경량골재를 제조하였으며, 알칼리 활성화 석탄회 인공경량골재의 콘크리트 적용을 위한 실험적 연구를 수행하였다. 따라서, 알칼리 활성화된 석탄회 경화체의 최적 배합비, 알칼리 활성화 석탄회 경화체와 인공경량골재의 기본적 특성, 역학적 특성과 환경안전성, 알칼리 활성화 석탄회 인공경량골재를 사용한 콘크리트의 역학적 특성과 동결음해저항성을 파악하였다 실험결과 알칼리 활성화 석탄회 인공경량골재를 제조하기 위한 경화체의 최적 배합비는 시멘트 $10\%$, Water glass $15\%$, NaOH $10\%$, $MnO_2\;5\%$였으며, 혼합물을 $50^{\circ}C$ 항온습윤양생 24k후 상온 공기중 양생을하여, 7일 압축강도 36.4MPa를 얻을 수 있었다. 제조된 골재의 폴리머 함침 결과 $10\%$ 파쇄강도를 $150\%$ 향상시킬 수 있었으며, 콘크리트용 굵은 골재로의 활용 가능성을 파악할 수 있었다.

• Journal of Ceramic Processing Research
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• 제21권6호
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• pp.622-631
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• 2020

Fly ash is an industry by-product of thermal power factories that is broadly utilized in the concrete industry. This research shows a framework for evaluating the hydration heat, reaction amount, and strength progress of cement-fly ash binary composite. First, we conducted an experiment to study the isothermal hydration heat of fly ash composite paste with assorted fly ash contents and temperatures. According to the experimental outcomes of cumulative hydration heat, the coefficients of a kinetic reaction model of fly ash were determined. Furthermore, the reaction amount of fly ash was calculated using a fly ash reaction model. We discovered that the reaction of fly ash is considerably improved at elevated temperatures. The reaction amount of fly ash decreases with the growing content of fly ash. Second, in line with the reaction amount of fly ash and cement, we developed a straight-line equation for evaluating the strength progress of binary composite. The strength progress model applies to a number of water-to-binder ratios and fly ash substitution ratios. Summarily, the suggested hydration-heat-strength model is helpful for understanding the material style of fly ash concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.481-484
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• 2006

The purpose of this study is to present the recycling method of reject-ash. The reject-ash, a significant portion of the pulverized fuel ash produced by coal-fired power plants and rejected from the ash classifying process, has remained unused due to its high carbon content and large particle size. This study compared reject-ash with fly-ash by physical properties, the properties of fresh & harden concrete with cement replacement ratio of reject-ash and fly-ash, 0, 5, 10, 15, 20, 25(wt. %). The loss of ignition of the reject-ash is similar to fly-ash and is suited to the KS L 5405. When the replacement ratio of reject-ash is increasing the air content of reject-ash concrete is lowly decreased. The results of the compressive strength measurement of reject-ash tends to decrease by increasing the replacement ratio.

• 한국건축시공학회지
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• 제9권3호
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• pp.73-78
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• 2009

Coal ash is a by-product of the combustion of pulverized coal, and much of this is dumped in landfills. The disposal of coal ash is one of the major issues for environmental problems. In this paper, the effects of the kinds and replacement ratio of coal ash on the durabilities of concrete mixtures are investigated. Fine aggregate was replaced with coal ash(fly ash and bottom ash) in five different ratios, of 0%, 10%, 20%, 35%, and 50% by volume. Test results indicated that the compressive strength increased with the increase in fly ash percentage. The loss of compressive strength of bottom ash concrete mixes after immersion in sulphuric acid solution was less than in the control mix(BA0). In addition, the carbonation depth of fly ash concrete mixes was lower than the control mix(FA0).

• 한국세라믹학회지
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• 제53권4호
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• pp.435-443
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• 2016

Coal ash, a material generated from coal-fired power plants, can be classified as fly ash and bottom ash. The amount of domestic fly ash generation is almost 6.84 million tons per year, while the amount of bottom ash generation is 1.51 million tons. The fly ash is commonly used as a concrete admixture and a subsidiary raw material in cement fabrication process. And some amount of bottom ash is used as a material for embankment and block. However, the recyclable amount of the ash is limited since it could cause deterioration of physical properties. In Korea, the ashes are simply mixed and used as a replacement material for cement. In this study, an attempt was made to mechanically activate the ash by grinding process in order to increase recycling rates of the fly ash. Activated fly ash was prepared by controlling the mill types and the milling times and characteristics of the mortar containing the activated fly ash was analyzed. When the ash was ground by using a vibratory mill, physical properties of the mortar mixed with such fly ash were higher than the mortar mixed with fly ash ground by a planetary mill.

• 한국건축시공학회지
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• 제8권5호
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• pp.59-65
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• 2008

In the evaluation method of KS on the activity factor of fly ash, same amount of cement should be replaced with fly ash. Therefore, contradictory effects on concrete strength exist, i. e. strength decease due to low content of cement and strength increase of strength due to filling-pore-function of fly ash. European Committee for Standardization (CEN) specifies the method 1 to 4. adding fly ash without reducing the content of cement, for the evaluation method on activity factor of fly ash. This study investigates the applicability of the method 2 of CEN to mix design of concrete. The followings are derived ; There is a key ratio of f)y ash mixing which enhances the incremental ratio of mixing water to improve fluidity of mortar. The incremental ratio of mixing water is maximized about 11% ratio of fly ash mixing. Compressive strength most slightly increases at that ratio of fly ash mixing. Activity factor of fly ash increases as water-cement ratio becomes low and contents of fly ash becomes high. Moreover, quality of fly ash and condition of mix design affect the applicable amount of fly ash and available range of water-cement ratio. However, this method has some problems for practical purpose because activity factors of fly ash for some cases are over 1.0. Further research should be conducted to develop more useful method of evaluating activity factor of fly ash.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.513-520
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• 1999

20 million tons of coal ash has been produced in Korea annually. This causes the environmental problems and the cost of land for ash pond. However the amount of coal ash for recycling is small because of the low level of recycling technology and the ignorance. As the coal ash has the significant engineering properties, it can be utilized as soft ground stabilizer, backfill materials and so forth. The purpose of this paper is to summarize some of the recycling methods of coal ash. One is structural backfill materials, the other is flowable fill. Optimal mixture ratio(fly ash : bottom ash) is determined for structural backfill materials and the model test is performed. The model test accompanied with physical tests were executed for identifying that the flowable fly ash can be used as fill materials such as trench back filling.

• 한국건축시공학회지
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• 제2권3호
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• pp.115-121
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• 2002

The purpose of this study is investigating characteristics of paper-ash mortar according to partial replacement of fine aggregate by Paper-ash. For this purpose, selected test variables were mixing ratio with two levels of mortar(1:2, 1:3), and 3 types of paper-ash(A, B, C), and paper-ash content with four levels(5%,, 10%, 15%, 20%). As a result of this study, in all mixes with partial replacement of fine aggregate by Paper-ash generally Produced Paper-ash mortar with decreased compressive strength at ail age as compared to ordinary mixes. The mixing rate 1:2 was the higher increasing rate of strength than the mixing rate 1:3. The flow value and unit weight of paper-ash mortar were decreased with increasing of the paper-ash content. And the thermal conductivity of the thermal conductivity of the paper-ash mortar was lower than normal mixing without paper-ash.

• 콘크리트학회논문집
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• 제14권2호
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• pp.223-230
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• 2002

본 연구의 목적은 저강도 고유동 재료(CLSM)로서 매립처리 되는 bottom ash의 재활용 가능성을 실험하는데 있다. 저강도 고유동 재료는 포틀랜드 시멘트, 플라이애시, 모래, 물의 혼합으로 만들어지는 결합성 재료로서 재료의 타설과 동시에 유동성과 셀프레벨링성을 나타낸다. 플라이애시만을 사용한 배합이 bottom ash가 저강도 고유동 재료로서 사용가능한 내구성능을 나타내는지 비교하기 위하여 같이 실험되었다. bottom ash를 사용한 배합의 내구성능은 해로운 물리, 화학적 환경에서 실험되었으며 그 결과로서 bottom ash를 사용한 저강도 고유동 재료의 내구성능은 비구조 부재의 충전을 위한 적용분야에서 사용가능하게 나타났다. 또한 bottom ash를 첨가한 저강도 고유동 재료는 환경적으로도 안전하게 나타났다.