Production of geopolymer mortars with waste materials

The reuse of waste materials has become a significant research area to reduce environmental impacts and develop sustainable building materials. In this study, the feasibility of using various combinations of boron waste, silica fume, and fly ash in the production of geopolymer mortar was investigated experimentally and statistically. The Taguchi optimization method was employed to efficiently utilize waste materials and improve the strength, durability, and thermal properties of geopolymer mortars. Four main factors (boron waste, silica fume, sodium concentration, curing temperature and curing hour) were tested at five different levels, resulting in a total of 16 different mortar mixtures. The strength and thermal properties were examined by using end-of-life tire in amounts ranging from 10% to 100% to reduce the sand content in mortar mixtures with the best thermal properties. A total of 54 different mortar mixtures were evaluated. The Taguchi method provides an important roadmap for the development of geopolymer mortar technology. The evaluation through analysis of variance (ANOVA) played a crucial role in determining the optimum parameters. It has been observed that curing temperature plays a significant role in increasing the mechanical strength of the mortar. While the effect of silica fume is limited, the amount of boron waste emerges as a critical factor influencing both the strength and thermal conductivity of the mortar. Additionally, the effects of acid, sulfate, and high temperatures on the microstructure and mineral composition of selected mortars were discussed.