The Performance and Reaction Mechanism of Untreated Steel Slag Used as a Microexpanding Agent in Fly Ash-Based Geopolymers
Steel slag is an industrial by-product of the steelmaking process, which is under-utilized and of low value due to its characteristics. Alkali-activated technology offers the possibility of high utilization and increased value of steel slag. A geopolymer composition was composed of steel slag, fly a...
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MDPI AG
2024-02-01
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| Series: | Buildings |
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| Online Access: | https://www.mdpi.com/2075-5309/14/2/463 |
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| author | Jun Zang Chunlei Yao Bing Ma Zhiyuan Shao Houhu Zhang Jiaqing Wang Binbin Qian Hao Zhou Yueyang Hu |
| author_facet | Jun Zang Chunlei Yao Bing Ma Zhiyuan Shao Houhu Zhang Jiaqing Wang Binbin Qian Hao Zhou Yueyang Hu |
| author_sort | Jun Zang |
| collection | DOAJ |
| description | Steel slag is an industrial by-product of the steelmaking process, which is under-utilized and of low value due to its characteristics. Alkali-activated technology offers the possibility of high utilization and increased value of steel slag. A geopolymer composition was composed of steel slag, fly ash, and calcium hydroxide. Four experimental groups utilizing steel slag to substitute fly ash are established based on varying replacement levels: 35%, 40%, 45%, and 50% by mass. The final samples were characterized by compressive strength tests, and Fourier-transform infrared spectroscopy measurements, thermogravimetric measurements, scanning electron microscopy with energy dispersive spectroscopy, X-ray diffraction, and mercury intrusion porosimetry were used to investigate the chemical composition and microstructure of the final products. Higher steel slag/fly ash ratios lead to a lower bulk density and lower compressive strength. The compressive strength ranges from 3.7 MPa to 5.6 MPa, and the bulk density ranges from 0.85 g/cm<sup>3</sup> to 1.13 g/cm<sup>3</sup>. Microstructural and energy-dispersive X-ray spectroscopy analyses show that the final geopolymer products were a type of composite consisting of both calcium aluminate silicate hydrate and sodium aluminate silicate hydrate, with the unreacted crystalline phases acting as fillers. |
| first_indexed | 2024-03-07T22:40:07Z |
| format | Article |
| id | doaj.art-e0b9a895af644d6c9d1d2b78a0cd6db2 |
| institution | Directory Open Access Journal |
| issn | 2075-5309 |
| language | English |
| last_indexed | 2024-03-07T22:40:07Z |
| publishDate | 2024-02-01 |
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| record_format | Article |
| series | Buildings |
| spelling | doaj.art-e0b9a895af644d6c9d1d2b78a0cd6db22024-02-23T15:10:19ZengMDPI AGBuildings2075-53092024-02-0114246310.3390/buildings14020463The Performance and Reaction Mechanism of Untreated Steel Slag Used as a Microexpanding Agent in Fly Ash-Based GeopolymersJun Zang0Chunlei Yao1Bing Ma2Zhiyuan Shao3Houhu Zhang4Jiaqing Wang5Binbin Qian6Hao Zhou7Yueyang Hu8School of Architectural Construction, Jiangsu Vocational Institute of Architectural Technology, Xuzhou 221000, ChinaXuzhou Construction Engineering Testing Center Co., Ltd., Xuzhou 221000, ChinaNanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of the People’s Republic of China, Nanjing 210042, ChinaCollege of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, ChinaNanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of the People’s Republic of China, Nanjing 210042, ChinaCollege of Civil Engineering, Nanjing Forestry University, Nanjing 210037, ChinaSchool of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng 224002, ChinaNanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of the People’s Republic of China, Nanjing 210042, ChinaCollege of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, ChinaSteel slag is an industrial by-product of the steelmaking process, which is under-utilized and of low value due to its characteristics. Alkali-activated technology offers the possibility of high utilization and increased value of steel slag. A geopolymer composition was composed of steel slag, fly ash, and calcium hydroxide. Four experimental groups utilizing steel slag to substitute fly ash are established based on varying replacement levels: 35%, 40%, 45%, and 50% by mass. The final samples were characterized by compressive strength tests, and Fourier-transform infrared spectroscopy measurements, thermogravimetric measurements, scanning electron microscopy with energy dispersive spectroscopy, X-ray diffraction, and mercury intrusion porosimetry were used to investigate the chemical composition and microstructure of the final products. Higher steel slag/fly ash ratios lead to a lower bulk density and lower compressive strength. The compressive strength ranges from 3.7 MPa to 5.6 MPa, and the bulk density ranges from 0.85 g/cm<sup>3</sup> to 1.13 g/cm<sup>3</sup>. Microstructural and energy-dispersive X-ray spectroscopy analyses show that the final geopolymer products were a type of composite consisting of both calcium aluminate silicate hydrate and sodium aluminate silicate hydrate, with the unreacted crystalline phases acting as fillers.https://www.mdpi.com/2075-5309/14/2/463steel slagfly ashgeopolymerexpansion mechanism |
| spellingShingle | Jun Zang Chunlei Yao Bing Ma Zhiyuan Shao Houhu Zhang Jiaqing Wang Binbin Qian Hao Zhou Yueyang Hu The Performance and Reaction Mechanism of Untreated Steel Slag Used as a Microexpanding Agent in Fly Ash-Based Geopolymers Buildings steel slag fly ash geopolymer expansion mechanism |
| title | The Performance and Reaction Mechanism of Untreated Steel Slag Used as a Microexpanding Agent in Fly Ash-Based Geopolymers |
| title_full | The Performance and Reaction Mechanism of Untreated Steel Slag Used as a Microexpanding Agent in Fly Ash-Based Geopolymers |
| title_fullStr | The Performance and Reaction Mechanism of Untreated Steel Slag Used as a Microexpanding Agent in Fly Ash-Based Geopolymers |
| title_full_unstemmed | The Performance and Reaction Mechanism of Untreated Steel Slag Used as a Microexpanding Agent in Fly Ash-Based Geopolymers |
| title_short | The Performance and Reaction Mechanism of Untreated Steel Slag Used as a Microexpanding Agent in Fly Ash-Based Geopolymers |
| title_sort | performance and reaction mechanism of untreated steel slag used as a microexpanding agent in fly ash based geopolymers |
| topic | steel slag fly ash geopolymer expansion mechanism |
| url | https://www.mdpi.com/2075-5309/14/2/463 |
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