
Civil Engineering Faculty Publications and Presentations
Experimental assessment of cement hydration and leaching characteristics for waste-to-energy bottom ash mixed with concrete
Document Type
Article
Publication Date
2021
Abstract
To achieve a more sustainable waste-to-energy (WTE) process, the recycling of solid waste incineration (MSWI) bottom ash (BA) has received large attention nowadays. This study investigated how WTE BA form is changed after the hydration and the impacts of WTE BA hydration on its leaching characteristics by using geometrical and leaching tests when incorporated in cement matrix for the recycling. The material composition and characteristics of anhydrous BA, hydrated BA, cement paste, Portland cement concrete (PCC), and BA-combined PCC were evaluated through scanning electron microscopy, X-ray spectroscopy and X-ray diffraction analyses. The results confirmed that the WTE BA newly formed a complex phase of hydration products in a cement matrix. Synthetic precipitation leaching procedure (SPLP) test was also conducted to investigate the leaching behaviors of alkaline components and metals of BA in the crushed BA-PCC samples. Through the leaching study, the leachability of crushed BA-combined concrete was rigorously evaluated when recycled as construction materials (e.g. base, subbase, subdrainage, etc.), which is the worst–case scenario. The results revealed that the release of highly alkaline elements increases with increasing BA content. However, the release of trace metals was reduced by 20-30% significantly when mixed properly with Portland cement concrete (PCC), which is due to both physical and chemical binding in cement hydration products. In addition, the thresholds of water regulations, set by the World Health Organization (WHO) and the Environmental Protection Agency (EPA) of the United States, were assessed as the basis for evaluating the extent of the risk of the leaching of toxic materials.
Recommended Citation
An, Jinwoo, Boo Hyun Nam, Byoung Hooi Cho, and Jongwan Eun. "Experimental assessment of cement hydration and leaching characteristics for waste-to-energy bottom ash mixed with concrete." Journal of the Air & Waste Management Association 71, no. 7 (2021): 906-922. https://doi.org/10.1080/10962247.2021.1911874
Publication Title
Journal of the Air & Waste Management Association
DOI
10.1080/10962247.2021.1911874
Comments
© 2021 A&WMA
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