Red Mud (RM), a byproduct of the Bayer’s process, possess significant environmental challenges due to its limited applications beyond landfill disposal. This study investigates the feasibility of developing a novel geopolymer by incorporating Red Mud, Ground granulated blast furnace slag (GGBS) and Metakaolin (MK) mixtures using the simplex-centroid experimental design method and optimize the ternary binder mix with respect to setting time and compressive strength. The role of appropriate mineral proportions presents in all three binders activated with sodium hydroxides were studied to understand their influence on the synthesized geopolymers mixtures. Alkaline activators comprising NaOH and Na₂SiO₃ in a 1:2.5 ratio was used in this study. NaOH molarity was varied between 8, 10 and 12 to identify the optimal concentration. Seven mortar mixes for each molarity were prepared with Alkaline-to-Binder (Al/B) ratio of 0.5 and assessed for setting time and compressive strength under ambient conditions (7 and 28 days) and thermal curing (80 °C for 6 hours). Special cubic model equations were developed to quantify component interactions, with model validity confirmed by high predictive accuracy (R² > 0.95). Quantitative modeling demonstrates that the enhanced effect of the ternary systems compared to binary blends. The mixes with 10M NaOH exhibited better performance across the parameters evaluated. The optimal binder proportions lie within the range of 50–55% GGBS, 20–35% RM, and 20–30% MK. Microstructural studies through X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses confirmed a higher degree of geopolymerization, demonstrating a viable alternative to conventional RM disposal as sustainable construction material.
