Decision of Optimized Mix Design for Lightweight Foamed Concrete Using Bottom Ash by Statistical Procedure

Abstract

The increased demand and consumption of coal has intensified problems associated with disposal of solid waste generated in utilization of coal. Major utilization of coal by-products has been in construction-related applications. Since fly ash accounts for the part of the production of utility waste, the majority of scientific investigations have focused on its utilization in a multitude of use, while little attention has been directed to the use of bottom ash. As a consequence of this neglect, a large amount of bottom ash has been stockpiled. However, the need to obtain safe and economical solution for its proper utilization has been more urgent. The study presented herein is designed to ascertain the performance characteristics of bottom ash, as autoclaved lightweight foamed concrete product. The laboratory test results indicated that tobermorite was generated when bottom ash was used as materials for hydro-thermal reaction. According to the analysis of variance, at the fresh state, water ratio affects on flow and slurry density of autoclaved lightweight foamed concrete, but foam ratio influences on slurry density, while, at the hardened state, foam ratio affects on the density of dry and the compressive strength but doesn't affect on flexural and tensile strength. In the results of response surface analysis, to obtain target performance, the most suitable mix condition for lightweight foamed concrete using bottom ash was water ratio of 70~80% and foaming ratio of 90~100%.

A Study on the Evaluation and Improvement of Permeability in Radial and Tangential Section of Domestic Softwoods

“…1 본 연구에서 사용된 bottom ash(바텀애쉬)는 화력발전소에서 석탄을 태우고 남은 회분으로 비중에 따라 fly ash(플라이애쉬) 와 bottom ash로 구분되며 bottom ash는 보일러 하부 저장조에서 포집되는 석탄회이다 (Maeng et al, 2014). bottom ash는 전체 발생하는 회분의 15-20% 정도로 발생량이 적고 재활용이 어렵다 (Kim et al, 2009). 흡습 능력이 뛰어난 규조토와 동일한 SiO 2 와 Al 2 O 3 와 같은 화합물을 함유하고 있고 SiO 2 가 50% 구성된 Bottom ash는 수분과 접촉 시 미량의 SiO 2 가 CaO와 수화하여 표면에 수화물을 형성하여 흡착성능을 요구하는 곳에 사용되고 있다 (Moon et al, 2012).…”

“…Bottom ash is generated as little as about 15-20% of the total ash generated and difficult to recycle (Kim et al, 2009). It contains compounds such as SiO 2 and Al 2 O 3 which is as remarkable in moisture absorption ability as diatomite and when bottom ash consisting of 50% SiO 2 is in contact with moisture, a small amount of SiO 2 gets rehydrated with CaO, which forms a hydrate on the surface to be used in where required adsorption adsorption performance is required (Moon et al, 2012).…”

A Study on Distribution and Characteristics of Heavy Metals and Unburned Carbon in Bottom Ash of Coal-Fired Power Plant

“…석탄회는 포 집되는 장소에 따라 크게 비산재(fly ash)와 바닥재(bottom ash)로 구분되며, 이중 비산재는 석탄회의 75∼80%정도 로서 대부분이 콘크리트 혼화재료 및 시멘트 클링커 제 조 원료로 재활용되고 있다 (Lee et al, 2001). 그러나 바 닥재의 경우 석탄회의 15∼20%를 차지하고 있어, 비산 재에 비해 발생량이 적고 물리 화학적 특성이 열등함에 따라 재활용이 어려워 대부분 매립 처분되고 있는 실정 이다 (Lee et al, 2001;Kim et al, 2009;Lim, 2002; 연구논문 화력발전소 바닥재의 중금속 및 미연탄소 분포 특성 연구 제51권 제6호 (Ahn, 2002;Nam et al, 2014;Freeman et al, 1997;Song, 2003;Ha et al, 1999).…”

The Durability of the Concrete Using Bottom Ash as Fine Aggregate

“…바텀애쉬를 경량골재나 경량기포콘크리트에 사용하기 위한 연구 (Jo et al 2004;Kim et al 2009a;2009b) 및 콘크리트용 골재로 사용하 기 위한 연구 Lee et al 2002) …”