Nanosilica is nano-sized silica (1–100 nm) used as a partial cement substitute to improve the physical and mechanical properties of mortar. In this study, nanosilica synthesized from fly ash using the hydrothermal method was incorporated into mortar with varying concentrations of 0%, 3%, 6%, 9%, and 12%. The tests included slump flow, setting time, density, and compressive strength. The resul…