Multi-criteria decision-making optimization-based fiber-reinforced waste ceramic powder-based geopolymer: toward a sustainable net zero/low CO2 emission building material

In this study, geopolymers (GMs) were produced using basalt fiber, polyamide fiber, and polypropylene fiber-reinforced and ground blast furnace slag (GBFS) waste ceramic powder (WCP). In the initial phase of the study, the optimal ingredient proportions were identified, and an ideal geopolymer was selected based on its highest compressive strength. Subsequently, at the second stage of the study, various fibers with differing proportions were incorporated into the ideal geopolymer, and the resulting properties were evaluated through laboratory testing. In the third stage, the optimal GMs were determined through a holistic approach, employing a multi-criteria decision-making method. A total of ten mixtures, comprising 23 properties (230 parameters in total), were subjected to a multi-criteria decision support method (TOPSIS). The optimal GM mixture with the proportions and suitable components was identified. The findings indicated that a 20% substitution of WCP with GBFS resulted in an optimal and cost-effective mixture in a 10 M NaOH solution, serving as a reference point or ideal unreinforced mixture in this research. With regard to the addition of fibers, all three types of fibers were observed to enhance the compressive, flexural, and splitting tensile strength of the WCP–GBFS-based GM. Maximum compressive strength was observed to be 60.15 MPa, while the flexural strength was 12.98 MPa and the splitting tensile strength was 3.45 MPa for the polyamide fiber (PA)-reinforced GM. Furthermore, all reinforced GMs exhibited enhanced abrasion resistance, with the inclusion of polypropylene fibers yielding the best results. Additionally, these fiber-reinforced GMs demonstrated significant resistance to high temperatures, even as temperatures increased. The TOPSIS results indicated that PA0.8 was the optimal GM, and its components with suitable components were recommended as a sustainable net zero/low CO₂ emission building material.