Properties and mechanisms of geopolymers constructed from polymerized CGP-OSA- GGBS ternary-based solid wastes.

Industrial solid waste pollution is one of the current environmental problems that needs to be solved urgently. The construction of geopolymer gel materials using industrial solid wastes as precursors has become a research hotspot for solid waste recycling due to its preparation of excellent properties. Exploration preparation of ternary-based mass polymers (COSGM) from coal gangue powder (CGP), oil shale ash (OSA), and ground granulated blast furnace slag (GGBS) to address this challenge. In an extensive experiment involving forty-eight samples, three ratios of CGP to OSA (2:1, 1:1, 1:2), a liquid-to-binder ratio of 0.45, and GGBS content (15 %, 20 %, 25 %, and 30 %) were explored. Additionally, the impact of Na 2 SiO 3 modulus (0.4, 0.6, 0.8, 1.0 M) and alkali activator content (16 %, 18 %, 20 %, 22 %) on the COSGM's fluidity, setting time, compressive strength, and flexural strength was thoroughly investigated. In addition, microanalytical methods including XRD, FTIR, SEM, and EDS were utilized to reveal the mechanism of their work performance. The results indicated that the COSGM presented a higher strength with the optimal ratio range of COSGM at 30 % of GGBS content, Na 2 SiO 3 modulus at 0.4–0.6 M, and alkali activator content at 20 % and 22 %. Its compressive and flexural strength can reach up to 46.3 MPa and 6.1 MPa respectively, which means it can be employed to replace cement. The factors affecting the working performance of COSGM are in the order of GGBS content> Na 2 SiO 3 modulus>alkali activator content>CGP:OSA. The higher density and quantity of N-A-S-H, C-A-S-H and C-N-A-S-H gels in the COSGM contribute to the increase in the strength of the geopolymer. Therefore, the developed ternary geopolymer has the potential to promote a large-scale utilization of industrial solid wastes. • Proposed a novel ternary CGP-OSA-GGBS geopolymer. • The feasibility of replacing cement with ternary CGP-OSA-GGBS geopolymers is demonstrated. • Both OSA and GGBS play key roles in the properties of COSGM. • The type and density of the gel can reflect the geopolymer strength. [ABSTRACT FROM AUTHOR]