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Variations in Heavy Metal Analytical Results and Leaching Characteristics of Coal Ash Recycled Concretes according to Sample Crushing Methods
분쇄방법에 따른 석탄재 재활용 콘크리트의 중금속 분석결과 및 용출특성 변화
Econ. Environ. Geol. 2018 Oct;51(5):429-38
Published online October 31, 2018;  https://doi.org/10.9719/EEG.2018.51.5.429
Copyright © 2018 the Korean society of economic and environmental gelology.

Jin Won Lee1, Seung-Hyun Choi1, Kangjoo Kim1* and Bo-Kyung Moon2
이진원1 ·최승현1 ·김강주1* ·문보경2

1Department of Environmental Engineering, Kunsan National University, Kunsan 54150, Korea
2Korea Western Power, Co., Ltd., Taean, Chungnam 32140, Korea
1군산대학교 환경공학과, 2한국서부발전(주)
Received August 14, 2018; Revised October 3, 2018; Accepted October 18, 2018.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
 Abstract
Since concrete is a hardened aggregates of various materials, it needs to be crushed for chemical analyses. However, the effect of sample crushing on the analytical results has not been precisely assessed till today. In this study, we prepared concrete test pieces using Portand cements and fly ashes as binding materials, and ponded ashes and sands as aggregates and analyzed the heavy metals of the test pieces using Standards for Fair Testing of Soil Contamination (SFTSC) and Wastes (SFTW). For this, each test piece was partially crushed at first and sieved for separation of grains of <0.15 mm, 0.15-0.5 mm, and 0.5-5 mm from the same crushed samples (Crushing Method I). Results of those samples using SFTSC showed a clear trend that analyzed heavy metal concentrations are higher in the finer fractions. Particularly, fractions with <0.15 mm indicated much higher concentrations than the theoretical ones, which were calculated based on the concentrations of individual materials and their mixing fractions. In contrast, the analytical results were generally comparable with the theoretical ones when the test pieces were totally pulverized such that all the crushed grains were <0.15 mm in size (Crushing Method II). These results are associated with the fact that cement materials and fly ashes, which are high in heavy metals relative to other materials, are enriched in the fine fractions. The analytical results using the SFTW derived very low concentrations in most of parameters and did not indicate the dependence of concentrations on the crushing methods due to using distilled water as leaching agent.
Keywords : concrete, sample preparation, cement, coal ash, heavy metal analysis, Standard for Fair Testing of Soil Contamination

 

October 2018, 51 (5)