Flowability, Carbon Sequestration, and Strength Properties of Carbonation-Cured Solid Waste-Based Backfilling Materials

作者：Qifeng Jia, Leilei Shen, Zihao Zhou, Shuangming Wang, Lang Liu, Yuqi Wang, Yichen Li, Jingyu Wang · 发表于：Energy & Fuels · 年份：2025 · DOI：10.1021/acs.energyfuels.5c04093 · 被引用次数：7 · 研究领域：Tailings Management and Properties、Concrete and Cement Materials Research、Recycled Aggregate Concrete Performance

To address the critical challenges of low industrial solid waste utilization, excessive CO 2 emissions, and land subsidence in coal mine goaf areas, this study developed an innovative solid waste-based backfill material (SFC) through CO 2 -activated curing of steel slag, fly ash, and coal gangue (CG). The research systematically evaluated the SFC slurry’s flow characteristics, carbon sequestration capacity, and mechanical strength following CO 2 curing. The results indicate that the slurry yield stress and thixotropy initially increase and subsequently decrease with the rising CG content. Among the tested formulations, SFC5 exhibits the highest yield stress (171 Pa) and thixotropic hysteresis area (11,198 Pa/s). Nevertheless, all SFC formulations meet the minimum flowability requirements for underground mine backfilling applications. Besides, both carbon sequestration efficiency and compressive strength increase with extended curing age, whereas at 21 days of CO 2 -activated curing, these properties decrease with rising CG content. Significantly, all formulations except SFC20 exceed the 6 MPa threshold required for mine backfill applications. And when the utilization of CG is considered, SFC15 is the optimal material combination that achieves the best balance of flowability, carbon sequestration, and strength properties. This study develops an SFC backfill material that complies with mine backfill specifications, establishing a scientific basis for integrated management of co...