In this study, Ordinary Portland Cement (OPC) was partially substituted with various industrial by-products, including Glass Waste Powder (GWP) and Microfine (MF), in varying proportions of 0%, 10%, 20%, 30%, 40%, and 50% for GWP, and 5%, 10%, 15%, and 20% for MF. Additionally, Manufactured Sand (M Sand) was utilized as a complete replacement for natural river sand. The workability in terms of flow table and the compressive strength at 7 and 28 days was evaluated for different 22 binary and ternary blanded mortar mixes. Afterward, all the mortar mixes were exposed at 200 \(^\circ{\rm C} \) , 400 \(^\circ{\rm C} \) , 600 \(^\circ{\rm C} \) , and 800 \(^\circ{\rm C} \) temperature in order to examine the residual compressive strength of each mix. Moreover, the results of workability, compressive strength, and residual compressive strength were employed in TOPSIS analysis for the evaluation of the optimized mix among 22 different binary and ternary mixes. According to TOPSIS analysis, it was observed that the CG3M2 (60% cement + 30% GWP + 10% MF) was the optimized mix among all the mixes. Afterward, the comparison of the optimized mix and control mix was evaluated for the microstructural properties in terms of SEM/EDS, XRD, and TG/DTG. It was noted that the dense microstructure was formed in the optimized mortar, resulting in a higher compressive strength compared to the control concrete, resulting in very little decrement in the compressive and microstructural properties after temperature exposure. Moreover, the mineral formations of the optimized concrete are higher than those of the control concrete. It was concluded that the viability of the GWP and MF to generate effective fire resistance mortar in the field of construction industy.
