Journal Published Online: 04 April 2024
Volume 52, Issue 4

Mechanical and Microstructural Analysis of Lightweight Subgrade Bricks Synthesized from Mixtures of Coal Fly Ash and Sewage Sludge

CODEN: JTEVAB

Abstract

The massive discharge of coal fly ash and sewage sludge has placed great pressure on the environment and society. This study proposes a feasible method for producing lightweight subgrade bricks from coal fly ash and sewage sludge. The results show that the lightweight subgrade bricks mainly consist of mullite (3Al2O3·2SiO2), hematite (Fe2O3), sillimanite (Al2SiO5), aluminum phosphate (AlPO4), and a small amount of cristobalite (SiO2). The formation of AlPO4 improved the sintering and mechanical properties of the sintered samples. The formation of voids and cracks in the sintered samples was primarily attributable to the combustion and sintering shrinkage of the organic matter in the mixture. The maximum compressive and flexural strengths were observed when the sewage sludge content was 40 wt. %, and the corresponding compressive strength and flexural strength were 19.86 and 8.57 MPa, respectively. An appropriate amount of sewage sludge improves the connections between coal fly ash particles and promotes the densification of the lightweight subgrade bricks. These results provide a direction for the development of applications for coal fly ash and sewage sludge in the field of building materials.

Author Information

Wang, Hong
School of Metallurgical Engineering, Anhui University of Technology, Maanshan, Anhui Province, China Smelting Branch, Beijing Metallurgical Equipment Research Design Institute Co., Ltd., Beijing, China
Yu, Laihao
School of Metallurgical Engineering, Anhui University of Technology, Maanshan, Anhui Province, China
Zhang, Zhenghao
School of Metallurgical Engineering, Anhui University of Technology, Maanshan, Anhui Province, China Technology Center of the Ministry of Science and Technology, Shanghai Meishan Iron and Steel Limited by Share Ltd., Nanjing, Jiangsu Province, China
Zhang, Yingyi
School of Metallurgical Engineering, Anhui University of Technology, Maanshan, Anhui Province, China
Shen, Xin
School of Metallurgical Engineering, Anhui University of Technology, Maanshan, Anhui Province, China
Peng, Shiheng
School of Metallurgical Engineering, Anhui University of Technology, Maanshan, Anhui Province, China
Pages: 13
Price: $25.00
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Details
Stock #: JTE20230394
ISSN: 0090-3973
DOI: 10.1520/JTE20230394