• Title/Summary/Keyword: ash

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Strength Improvement of Lime-treated Soil with Fly Ash and Rice Husk Ash (Lime - Fly Ash / Rice Husk Ash에 의한 해성퇴적토의 강도특성 개선)

  • 민덕기;황광모;이경준;김현도
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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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.

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Alkali-Activated Coal Ash(Fly Ash, Bottom Ash) Artificial Lightweight Aggregate and Its Application of Concrete (알칼리 활성화 석탄회(Fly Ash, Bottom Ash) 인공경량골재 및 콘크리트 적용)

  • Jo Byung-Wan;Park Seung-Kook;Kwon Byung-Yoon
    • Journal of the Korea Concrete Institute
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    • v.16 no.6 s.84
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    • pp.751-757
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    • 2004
  • Artificial lightweight aggregates and solids were manufactured with coal ash(fly ash, bottom ash). In order to apply alkali-activated coal ash(fly ash, bottom ash) artificial lightweight aggregate to concrete, several experimental studies were performed. Thus, it can be noticed the optimal mix proportion, basic characteristies, mechanical properties and environmental safety of alkali-activated coal ash(fly ash, bottom ash) solid and alkali-activated coal ash(fly ash, bottom ash) artificial lightweight aggregate. Also, the freezing-thawing test property of concrete using the alkali-activated coal ash(fly ash, bottom ash) artificial lightweight aggregate was investigated. As a result, the optimal mixing proportion of coal ash(fly ash, bottom ash) solid to make alkali-activated artificial lightweight aggregates was cement $10\%$, water glass $15\%$, NaOH $10\%$, $MnO_2\;5\%$. Alkali-activated coal ash(fly ash, bottom ash) solid can achieve compressive strength of 36.4 MPa, at 7-days, after the paste was cured at air curing after moist curing during 24 hours in $50^{\circ}C$. Alkali-activated coal ash(fly ash, bottom ash) artificial lightweight aggregate that do impregnation to polymer was improved $10\%$ crushing strength $150\%$, and was available to concrete.

The Properties of Concrete with Reject Ash (리젝트애쉬를 사용한 콘크리트 특성)

  • Baek, Chul-Woo;Kim, Ho-Soo;Park, Cho-Bum;Ryu, Deuk-Hyun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05b
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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.

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A Study on the Durabilities of High Volume Coal Ash Concrete by the Kinds of Coal Ash (석탄회 종류에 따른 석탄회를 대량 사용한 콘크리트의 내구특성에 관한 연구)

  • Choi, Se-Jin;Kim, Moo-Han
    • Journal of the Korea Institute of Building Construction
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    • v.9 no.3
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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).

A Study on Physical Properties of Mortar Mixed with Fly-ash as Functions of Mill Types and Milling Times

  • Seo, Sung Kwan;Chu, Yong Sik;Shim, Kwang Bo;Jeong, Jae Hyun
    • Journal of the Korean Ceramic Society
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    • v.53 no.4
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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.

Fundamental Study on Evaluation method of Activity Factor of Fly Ash (플라이애시의 활성도지수 평가에 관한 기초적 연구)

  • Park, Sang-Joon
    • Journal of the Korea Institute of Building Construction
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    • v.8 no.5
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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.

A Study on the Recycling of Coal Ash as Fill Materials (석탄회 자원의 채움재로서의 활용에 관한 연구)

  • 천병식;고용일;송경율;이준기
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.03a
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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.

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An Experimental Study on the Properties of Mortar Mixing Paper Ash (제지애쉬를 혼입한 모르터의 특성에 관한 실험적 연구)

  • Lee, Si-Woo
    • Journal of the Korea Institute of Building Construction
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    • v.2 no.3
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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.

Durability Characteristics and Environmental Assessment of Controlled tow-Strength Materials Using Bottom Ash (Bottom Ash를 재활용한 저강도 고유동 재료의 내구성 및 환경영향 평가)

  • 원종필;이용수;이존자
    • Journal of the Korea Concrete Institute
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    • v.14 no.2
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    • pp.223-230
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    • 2002
  • The main intent of this research was to determine the feasibility of utilizing recycling bottom ash as CLSM (controlled low-strength material). CLSM is a cementitious material, commonly a blend of portland cement, fly ash, sand, and water, that is usually flowable and self-leveling at the time of placement. The durability characteristics of mixtures made bottom ash we compared with those of fly ash CLSM in order to evaluate the effectiveness and suitability of bottom ash as material in CLSM. A comprehensive evaluation of the bottom ash in CLSM and mix proportions indicated that the bottom ash are capable of performing as CLSM mixtures. The durability characteristic of CLSM incorporating the bottom ash under various physical and chemical causes of deterioration were investigated. Test results indicated that CLSM using bottom ash has acceptable durability performance. CLSM incorporating with bottom ash were also found to be environmentally safe.

Influence of Fly Ash Quality on Rheological Properties of Cement Paste (플라이애시 품질이 시멘트 페이스트 레올로지 특성에 미치는 영향)

  • Baek, Byung-Hoon;Han, Dongyeop
    • Journal of the Korea Institute of Building Construction
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    • v.17 no.2
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    • pp.183-189
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    • 2017
  • The aim of the research is to provide rheological properties of cement paste with various qualities of coal ash including fly ash, raw ash, and reject ash. Generally, fly ash is the well known supplementrary cementitious materials for concrete and is used to improve various properties. Although fly ash is obtained as a byproduct of fire powder plant, still reject ash is wasted from raw ash. In this research, thus, to provide a fundamental information on using not only fly ash but also raw ash or reject ash for cementitious materials, a rheological properties of cement paste was studied with three different coal ash. This research was conducted from particle conditions of three different coal ashes to rheological properties in cement paste phase. According to the expeirment, reject ash was consisted with large and coagulated particles although fly ash was consisted with a small and spherical shaped particles. based on the particle conditions of various coal ashes, rheological behaviors were tested, and it was shown as the coal ashes improved the fluidity of cement paste. Specifically, depending on the particle distributions of cement paste, it is considered that the viscosity of paste can be controlled.