Synergistic preparation of high-performance composite blast furnace slag powder from multiple industrial solid wastes: Performance regulation and optimization

• Published in: Construction & building materials 2024-01, Vol.411, p.134231, Article 134231
• Main Authors: Wu, Pengfei, Zeng, Qingsen, Liu, Xiaoming, Zhang, Zengqi, Wei, Chao, Li, Yantian, Ma, Shanliang
• Format: Article
• Language: English
• Subjects: Composite blast furnace slag; Environmental performance; Industrial solid waste; Medium-calcium systems; Synergistic effects
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2023.134231

Blast furnace slag (BFS) is commonly used as a substitute for cement clinker due to its hydration properties. However, the demand for BFS is outpacing the supply, and its price is rising steadily. Moreover, the significant accumulation of industrial waste with potential hydration properties poses a severe environmental threat. To address these challenges, this paper aimed to prepare high-performance composite blast furnace slag powder (CBFS) by incorporating red mud (RM), fly ash (FA), desulfurization gypsum (DG) and BFS, guided by the synergistic effects and the theory of medium-calcium systems. This paper reveals that the primary activation methods of the amorphous silicon-aluminum mineral phases in CBFS are alkali activation and sulfate activation. The optimal results demonstrate that the compressive strength of CBFS-cementitious material (50% CBFS + 50% cement) can reach 52.8 MPa, meeting the standards of Portland Cement PO 42.5. Additionally, RM, FA and DG account for 66% of CBFS and the hydration activity of CBFS is better than that of S95-grade BFS. Furthermore, the CBFS-cementitious material effectively immobilizes hazardous elements of the raw materials, and the leachate meets drinking water standards. The application of CBFS facilitates the recycling of industrial solid wastes, improves the quality of construction materials and reduces the construction industry's dependence on BFS. [Display omitted] •CBFS was prepared using RM, FA, DG, and BFS, aiming to achieve integrated clean production in multiple industries.•The total content of RM, FA and DG in CBFS reaches 66%, and its properties meet the requirements of S95-grade BFS.•RM, FA, DG and BFS showed a positive synergistic effect in CBFS, which enhanced the strength of the matrix (52.8 MPa).•CBFS can reduce carbon emissions in the cement industry and solidify the hazardous elements in the raw materials.