This work investigates the effects of silica fume (SF) and ZnO nanoparticles in enhancing the mechanical strength and durability of concrete. High-performance concrete specimens (w/b 0.34) were prepared, replacing cement with SF (4–16%) and combining 8% SF with ZnO (0.3–1.2%). Mechanical strengths and resistance to sulphate and chloride attack were assessed. Results identified 8% SF and 0.9% ZnO as the optimal dosage for ternary blends, yielding a 8.96% increase in compressive strength (p < 0.05) and reducing strength loss by 18.86% under sulphate exposure. Microstructural analysis (XRD and SEM-EDX) confirmed that ZnO acts as a nucleation agent, enhancing matrix densification following the initial retardation period, while SF consumes calcium hydroxide through long-term pozzolanic reactions. This synergistic interaction results in a refined, compact cementitious matrix, consistent with improved retention of mechanical performance under aggressive exposure conditions. Consequently, the optimized SF-ZnO composite offers a robust material for sustainable infrastructure in aggressive environments.
Kumar et al. (Tue,) studied this question.