Multifunctional Mortars Incorporating Granite Powder and ZnO Microparticles: Synergistic Approach to Mechanical Strength, Photocatalytic and Antimicrobial Activity

The accumulation of waste produced by stone-cutting industries poses a significant environmental challenge, while the construction sector negatively impacts the environment due to the intensive extraction of natural resources. In this context, integrating these two demands represents a sustainable solution, promoting a responsible approach to civil construction and energy efficiency. In addition, nanotechnology offers pathways for developing multifunctional materials combining mechanical, photocatalytic, and antimicrobial properties. This study investigates sustainable mortars incorporating granite powder as a partial replacement for natural sand, reducing natural aggregate consumption and promoting the reuse of industrial by-products. Additionally, zinc oxide microparticles (ZnO-MPs) were used as functional additives. Mortar mixtures containing 15% and 30% of granite powder and 0.33% of ZnO-MPs were prepared and evaluated. Photocatalytic capacity performance was assessed by methylene blue degradation, and antibacterial activity by the inactivation of Staphylococcus aureus . The results showed that replacing sand with 30% granite powder and incorporating 0.33% ZnO-MPs increased compressive strength by 33%, attributed to the microstructural densification and reduced pore volume provided by ZnO-MPs. These enhancements contribute to greater durability and reduced maintenance costs. The GP–ZnO-MP composite achieved 95% dye degradation under solar irradiation and exhibited antibacterial performance. Overall, the results demonstrate the synergistic potential of combining mineral waste and ZnO particles to produce eco-efficient mortars with structural, photocatalytic, and hygienic functionalities aligned with sustainable and circular construction principles. This innovative material shows potential for future applications in water and wastewater treatment. • Granite Powder replaced natural sand enhancing compressive strength by 33%. • Granite Powder–ZnO composites achieved 95% dye degradation under solar light. • ZnO microparticles densified the matrix and improved hydration kinetics. • Mortars exhibited significant antibacterial activity against Staphylococcus aureus . • Recycling waste in construction boosts energy efficiency of the overall process