Optimizing glass powder and slag-based geopolymers: enhancing thermo-mechanical strength resistance for sustainable construction applications

This research explores the potential of glass powder (GP) and ground granulated blast furnace slag (GGBS) in enhancing the properties of geopolymers for sustainable construction applications. By addressing the gap in research on slag-based geopolymers under elevated temperature conditions, the study aims to optimize these materials for improved mechanical strength, fire resistance, and workability. Response Surface Methodology (RSM) technique was adopted to develop mathematical equations for predicting and optimization of the fresh and compressive strengths of the GP-GGBS-based geopolymer at normal and elevated temperature exposure conditions. The variables used were NaOH molarity, sodium silicate to sodium hydroxide ratio (SS/SH), and GP content. The established models were found to have high level of significance, accuracy, and degrees of determination, the models were validated experimentally, and they demonstrated less percentage errors less than 6 %. From the multi-objective optimization (MoP) results, the optimal properties of the geopolymer attained were a flow value of 87.4 mm, setting time of 401.3 mins, compressive strength of 50.33 MPa, 54,88 MPa and 27.57 MPa at 28 °C, 200 °C and 800 °C respectively, cyclic compressive strength at 28 °C of 16.99 MPa. The optimal combinations of the variables were 14 M NaOH molarity, SS/SH of 2.45 m and GP content of 30 %. The MoP results have a high desirability of 0.959. Thus, the study emphasizes the prospective of optimizing GGBS-based geopolymer mixtures to improve thermo-mechanical properties, contributing to a sustainable utilization of waste materials.