High-performance belite rich eco-cement synthesized from solid wastes: Raw feed design, sintering temperature optimization, and property analysis

• Published in: Resources, conservation and recycling conservation and recycling, 2023-12, Vol.199, p.107211, Article 107211
• Main Authors: Lyu, Hanxiong, Hao, Lucen, Zhang, Shipeng, Poon, Chi Sun
• Format: Article
• Language: English
• Subjects: bottom ash; calcite; carbon dioxide; carbonation; Carbonation curing; compression strength; Incineration bottom ash; Mechanical performance; microstructure; municipal solid waste; Recycled concrete fine; silica gel; Sintering temperature; temperature; waste incineration
• ISSN: 0921-3449; 1879-0658
• DOI: 10.1016/j.resconrec.2023.107211

•A high-performance belite rich eco-cement was synthesized from solid wastes.•The utilization of solid wastes in the raw meal was up to 85.5 wt%.•Strong carbonation reactivity and latent hydraulic behavior promised high strength.•This technology contributed to CO2 emission reduction and solid waste management. In this study, a high-performance eco-cement with excellent CO2 sequestration capacity was synthesized using municipal solid waste incineration bottom ash and recycled concrete fine. The influence of clinkering temperature on the clinkers was assessed by mechanical properties, mineralogy, and microstructure. Optimal sintering at 1100 °C for 1 hour yielded eco-cement rich in β-C2S (44.9%), demonstrating remarkable carbonation reactivity (CO2 uptake of 12.5%) and compressive strength (1-day strength of 113.7 MPa). The presence of carbonation products, including cubic-shaped calcite and low Ca/Si C-S-H, resulted in a densified microstructure contributing to exceptional strength. Furthermore, the eco-cement exhibited latent hydraulic behavior and recorded a 28-day strength of 136.9 MPa. Varying clinkering temperatures to 1000 °C and 1200 °C promoted the formation of γ-C2S and rankinite, respectively, which generated silica gel during carbonation curing and weakened the overall performance. Leaching assessments confirmed the eco-cement's reasonable merit as an alternative, high-performance, sustainable binder. [Display omitted]