Multi-output optimisation of geopolymer mortar using Taguchi and TOPSIS method

In this study, a ternary blended geopolymer mortar was optimised by incorporating GGBS, metakaolin, and paper sludge ash using the hybrid Taguchi-TOPSIS method. An L 16 design was used to test various responses of their performance by varying four parameters, namely, GGBS, MK, PSA, and molarity, at four levels. The tested sample ANOVA results showed that the most significant effect was observed for a factor, molarity, at 71%, followed by GGBS 19%. The best proportion was observed as TBM-15 (70% GGBS, 15% MK, 7.5% PSA, 4 M NaOH), which had 83.20 N/mm 2 compressive strength after 28 days of testing, it also showed 65 percentage reduction in water absorption, and 40 percentage faster setting compared with the control. A dense C-A-S-H gel formation and enhanced microstructural integrity were also demonstrated by SEM, XRD, and FTIR analyses. A system of hybrid optimisation successfully reduced the number of trials but produced a strong, durable, and sustainable geopolymer binder.