A novel and clean utilization of red mud as an activator couple with fly ash to prepare cementitious paste backfill
Supplementary cementing materials (SCM) have gained significant attention as a substitute for ordinary Portland cement in cementitious paste backfill (CPB). Fly ash (FA) has been proven to be an economic and efficient SCM, however, the high cost of commercial activators needs to be well controlled....
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-12-01
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| Series: | Case Studies in Construction Materials |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214509525008423 |
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| Summary: | Supplementary cementing materials (SCM) have gained significant attention as a substitute for ordinary Portland cement in cementitious paste backfill (CPB). Fly ash (FA) has been proven to be an economic and efficient SCM, however, the high cost of commercial activators needs to be well controlled. In this study, the alkaline solid waste, red mud (RM), was utilized as an activator couple with FA to prepare CPB. The results show that mechanical properties of CPB with 1.5–4.5 wt% RM after 28 d decreased by 7.0–34.5 % compared to the control group (0 wt% of RM). The hydration products analysis revealed that the aluminum (from RM and FA) substitute silicon within CPB system, leading to the formation of more poorly compacted C(Na)-A-S-H gels. However, the enhancement of the microstructure of CPB specimens with RM could partially mitigate the negative effects of reduced hydration products within CPB specimens containing RM. Finally, the preparation cost of CPB specimens with 1.5 wt% RM is 20 % lower than that of specimens activated solely with NaOH. These results demonstrate potential of RM in alkali-activating FA, which advances its application in CPB fields. |
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| ISSN: | 2214-5095 |