|
Title |
Applicability Evaluation of Circulating Fluidized Bed Bottom Ash as a Supplementary Cementitious Material
|
|
Authors |
박금단(Keum-Dan Park) ; 조형규(Hyeong-kyu Cho) |
|
DOI |
https://doi.org/10.4334/JKCI.2025.37.6.707 |
|
Keywords |
시멘트 혼화재료; 순환유동층 보일러 바텀 애시; 분말도 supplementary cementitious material; circulating fluidized bed bottom ash; fineness |
|
Abstract |
This work evaluated the potential use of bottom ash generated from a circulating fluidized bed (CFB) boiler as a supplementary cementitious material (SCM). Bottom ash is generally underutilized due to its coarse particles, high porosity, and heterogeneous distribution, which results in non-uniform reactivity. To improve its usability, the ash was ground to two fineness levels (2,900 and 3,700 cm2/g) and used to replace ordinary Portland cement (OPC) at proportions ranging from 0 to 35 %. Its chemical and physical properties were analyzed using XRF, XRD, TG-DTG, and particle size measurement, and its effects on setting time, flowability, and compressive strength were evaluated. Increasing the replacement ratio delayed setting times and reduced early-age strength due to the dilution of reactive phases (C3S and C2S) and the presence of anhydrite (CaSO4). Flowability was not significantly influenced by fineness. Long-term strength improved, especially for the finer ash (3,700 cm2/g), which showed a narrower particle size distribution. The results suggest that CFB bottom ash with sufficient fineness can be used as an SCM in cement at replacement levels of up to 20 % without significantly compromising performance.
|