Durability evaluation of a high-performance red mud-based composite material

The industrial solid waste red mud (RM) was served as a raw material, supplemented with high activity of highcalcium fly ash (HCFA) and low-calcium fly ash (LCFA), a red mud-based composite material (RBC) was obtained. Through the activation of a mixed solution (MS) of NaOH and water glass and the optimization of the preparation process, the prepared RBC possessed a high-performance with high strength and environmental protection. The chemical corrosion and freeze-thaw properties of the RBC were investigated by full immersion and rapid freeze-thaw methods. The strength and durability mechanisms of the RBC were explored by microtesting techniques. The results indicated that adjusting the operated temperature of the alkaline activator can ensure paste compatibility and shorten the initial setting time. According to the integrity, economy and mechanics properties of the RBC, it is comprehensively determined that the method of wrapped steam-cured, the optimum curing time of RM-HCFA-MS and RM-LCFA-MS was 14 d and 21 d, respectively, and the corresponding compressive strength was 52.8 MPa and 58.9 MPa, respectively. When immersed in acidic, alkaline, or saline environments, the RBC consistently maintained its original structural morphology exhibiting strong corrosion resistance performance. Additionally, the maximum compressive strength was decreased by 19.5%, the maximum mass loss rate was 1.74%, and the corrosion resistance coefficients exceeded 75% after corrosion. The RBC was freeze-swelled and ruptured under repeated actions of hydrostatic and infiltration pressures, and the frost resistance ratings of RM-HCFA-MS and RM-LCFA-MS were F105 and F120, respectively. In conclusion, the RBC has good corrosion resistance and frost-thaw resistance.