Dual-activated calcined coal gangue for high-performance and eco-friendly cementitious materials
Coal gangue (CG) is a typical bulk solid waste that poses great environmental challenges due to improper disposal. In this study, calcined coal gangue (CCG) was used as the main raw material, and a dual activation method using sodium sulfate (NS) and silica coupling agent (SCA) was employed to addre...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-05-01
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| Series: | Journal of Materials Research and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425013110 |
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| Summary: | Coal gangue (CG) is a typical bulk solid waste that poses great environmental challenges due to improper disposal. In this study, calcined coal gangue (CCG) was used as the main raw material, and a dual activation method using sodium sulfate (NS) and silica coupling agent (SCA) was employed to address these limitations. The material composition was optimized, and a combination of tests, including compressive strength measurements, durability assessment in sulfate, alkaline, and ammonium chloride environments, and advanced characterization techniques was employed. The results showed that the optimized materials achieved compressive strengths of 35.15 MPa at 28 days and 41.55 MPa at 150 days. The synergistic formation of calcium silicate hydrate (C–S–H) and calcium vanadate (AFt) hydrocolloids was emphasized, resulting in a dense, stable microstructure. The hydration process of gangue cementitious materials is divided into three stages: dissolution of raw materials, formation of C–S–H gels, and Aft, and cementation and coalescence of hydration products. The development of strength is different in different environments, indirectly affecting the formation of C–S–H and AFt. The content of calcium hydroxide in the hydration process determines the degree of the hydration reaction. NS-SCA dual activation of gangue collodion materials also has a great improvement in the resistance of the materials to sulfate, strong alkali, and chloride salts, increasing their service life. This study provides a sustainable way to realize the value of gangue cementitious materials, reduce the damage to the environment during cement production, and promote the development of low-carbon building materials. |
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| ISSN: | 2238-7854 |