• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.901-904
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• 2008

Immense quantities of coal combustion by-products are produced every year, and only a small fraction of them are currently utilized. Therefore, this study investigated and analyzed the applications of porous concrete for the efficient utilization of bottom ash. This study examines on application of polymer to improve strength properties of porous concrete using coal-ash. As the results, when the mixing ratio of bottom ash increases, void ratio and coefficient of permeability of porous concrete increases, but its strength decreases. Also, as the mixing ratio of polymer increases, its void ratio and coefficient of permeability decreases. When specific amount of polymer is mixed, we can find its strength properties are improved.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.333-348
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• 2020

The present review dealt with the state-of-art on utilization of coal bottom ash in cement-based concrete and mortar. Two types of bottom ashes generated from pulverized coal combustion and circulating fluidized-bed combustion systems have been considered. The production process, chemical and physical characteristics of both ashes, and the methodology of utilization in various cement composites are summarized. The effect of bottom ash on various properties of concrete, such as workability, strength, and durability, were reviewed from the literature. In addition, the environmental and economic aspects of utilizing bottom ash in concrete are analyzed to explore the perspectives of bottom ash utilization, and through this, the future of the utilization was considered. The effect of bottom ash on the performance of concrete and mortar was greatly depended on the condition, pretreatment, and processing of the ash. Additional processing such as crushing might contribute to stimulating the utilization in this field. In particular, if economic support is possible in terms of policy, utilization rate is expected to be improved.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.701-704
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• 2008

Actuality, amount of electric power is rising together with business expansion. But the most power plant is consisted a thermal power. People have been burning fuel like a coal, and it bring the cinder concrete. Fly-ash is use to the high-degree in construction material, but in case of bottom-ash had been disused the whole quantity. Intermittently, the academic world laid his studies for bottom-ash. Thus, this study contents are a characteristic of be not harden concrete incorporating fine aggregate, a strength of harden concrete, elastic modulus and a unit mass. And there do for the sake to examine utility value of bottom-ash and improve of light weight concrete.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.349-355
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• 2016

This study is about the reuse of bottom ash, which is released as a necessity in thermal power plant. In general, coal-ash are classified as fly-ash, bottom-ash, cinder-ash. Of these, a large amount of fly ash is being recycled as cement substitutes. While, recycling rates of bottom ash are the lowest due to its porosity and high absorption. In this study, the durability of the concrete using bottom ash as a concrete fine aggregate was evaluated. The using level of the bottom ash ranges to step-by-step from 0% to 30%. According to the result of the durability test, regardless of the presence of the bottom ash, freeze-thaw durability could be secured by air entrainment. In case of the resistance to chloride ions penetration, the length change, and the effects on heavy metals, the replacement of bottom ash as fine aggregate was not critical. Although carbonation penetration was higher as the replacement level of bottom ash increased, the experiment showed that it could be possible to use bottom ash as concrete fine aggregate with proper mix design.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.685-688
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• 2008

This study has examined the effect of bottom ash(BA) on the properties of low heat-blended cement(LHC) and concrete. A number of binders were prepared by the replacement of LHC with BA in range of 5$^{\sim}$20wt%. The results showed that the final setting time of cement paste were delayed when the BA replaced part of the cement. However, The heat of hydration increased narrowly with adding BA in a early hydration period. The results also showed the inclusion of BA at replacement levels of 5$^{\sim}$10wt% resulted in an increase in compressive strength of the specimens compared with that of the control concrete and improved a resistance of concrete against the sulfate and chlorine ion.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.197-197
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• 2011

최근 들어 전력 사용량의 증가로 인한 화력발전소의 부산물인 석탄회 중 바텀애시와 각종 공공사업과 관련하여 해마다 현장발생토의 발생량이 지속적으로 증가하고 있는 추세이다. 바텀애시와 현장발생토사를 효과적으로 재활용하는 방법 중 유동성 뒤채움재를 개발하여 활용하는 방안을 모색하기 위한 연구이다. SP로 분류된 흙 현장발생토와 서천 화력발전소에서 발생하는 석탄회 중 입경이 0.9~1.5mm의 바텀애시만을 선별하여 현장발생토와 바텀애시의 비율을 7 : 3으로 변환한 최적배합을 선정하여 강재로 제작된 가로 80cm, 세로 60cm, 높이 90cm의 모형토조를 이용하여 실험을 진행하였으며, 사용상 지하 매설이 되는 관의 거동 특성은 확인하기 위하여 내경 30cm, 두께 8mm의 연선관 중 하나인 PVC관을 원형지하매설관으로 선정하여 배합을 타설하는 과정과 타설 후 7일간의 양생기간을 거친 후 차량하중으로 가정할 수 있는 하중을 가하여 원형지하매설관의 관외부에서 수직방향과 수평방향의 토압과 관내부의 수직 수평방향 변위 그리고 관 자체의 횡 종단 변형을 측정하여 원형지하매설관의 거동특성을 파악하였다. 타설시 지하매설관은 유동성 뒤채움재의 특성으로 인하여 시간이 지남에 따라 안정화되는 것을 확인할 수 있었으며, 최대하중을 3300kgf로 하여 하중 재하 후 지하매설관의 거동특성은 대체적으로 일반 모래를 사용하여 실험한 값보다 적은 변형 특성을 보이고 있으나 수평토압의 경우 일반적인 흙의 변형과 전혀 상이한 결과값을 보이는 경우도 있어 추가적인 실험 및 고찰의 필요하다. 본 실험에서 사용한 최적배합비 이외의 배합으로 같은 실험을 수행하여 바텀애시 량의 가감 및 재활용 재료인 폐타이어 고무칩등을 첨가한 실험을 계획하고 있으며 추후 실내시험과 모형실험을 토대로 유한요소해석을 추가로 시행하여 실험값과 해석값의 비교를 할 예정이다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.3
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• pp.173-179
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• 2014

This is an experimental study for recycling coal ash left over from coal use as a potential fine aggregate in concrete. Coal ash is generally divided into either fly ash or bottom ash. Fly ash has been utilized as a substitution material for cement in concrete mixes. On the other hand, bottom ash has the problem of low recycling rates, and thus it has been primarily reclaimed. This study partially substituted fine concrete aggregates with bottom ash to increase its application rate and therefore its recycling rate; its suitability for this purpose was confirmed. The concrete's workability dropped noticeably with increasing bottom ash content when a fixed water-cement ratio of concrete mix was used. Thus, concrete mixes with higher ratio levels are required. To address this problem, concrete was mixed using a polycarboxylate high-range water reducing agent. The fluidity and air entrainment immediately after mixing the concrete and 1 h after mixing were measured, thereby replicating the time concrete is placed in the field when produced either in a ready-mixed concrete or in a batch plant. As a result of this research, the workability and air entrainment were maintained 1 h after mixing for a concrete mixture with approximately 30% of its fine concrete aggregates substituted with the bottom ash. A slight drop in compression strength was seen; however, this confirmed that potential of using bottom ash as a fine aggregate in concrete.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.3
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• pp.252-260
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• 2015

The aim of this research is providing the fundamental data for treating and recycling the byproducts by using the wet processed bottom ash as a fine aggregate replacement for cement-based extruded panel. Although the cement-based extruded panel was used mainly as a cladding component with its high strength and outstanding durability, it was hardly spread because of low economic feasibility due to the high cost of additives or fibers which were used to achieve 14 MPa of flexural strength as a cladding material. As a solution of this drawback, by the previous research, it was possible to replace cement by fly ash up to 80 % by decreasing quality criteria with restricting the application to indoor purpose. In this research, based on the previous research, by using the bottom ash as a replacement of fly ash, improvement of shape retention performance is tried. As a result of the experiment on evaluating the optimum content and PSD of bottom ash, as the fineness modulus and content of bottom ash was increased, the extruding performance was decreased and penetration resistance was increased. Additionally, the optimum content and the maximum particle size was found as 20 %, and 0.3 mm, respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.92-93
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• 2014

This study was carried out to process the shape of dry bottom ash using the impact crusher and gravity crusher, which are identified as most effective in improving grain shape through the preceding research, and a comparison was made between concrete that utilized the processed dry bottom ash as aggregate and concrete containing dry bottom ash before processing to understand properties of the new concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.166-167
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• 2013

Bottom ash, which is discharged through a wet process in a thermal power plant, contains much unburned coal due to quenching and much salt due to seawater. However, dry bottom ash discharged through a dry process contains low unburned coal and salt, and has light -weight due to many pores. Therefore, it is expected that it can be used as lightweight aggregate. This study deals with the basic properties of concrete used dry bottom ash as coarse aggregate. As a results, the concrete having high content of dry bottom ash aggregate showed high slump by using water reducing agent and its air content was within 5±1.5% as designed value, similarly to normal weight concrete. It also showed a lower compressive strength than 100% of crushed stone.