Investigation of the effects of nano-silica on the properties of concrete in comparison with micro-silica

The effects of adding Nano-Silica particles on the compressive strength and water permeability of concrete and its comparison with that of Micro-Silica were investigated in this work. The effect of combination of Nano- silica and Micro-silica were also studied in this work, which resulted in an increase in compressive strength of concrete in comparison with other concrete specimens tested in this study. In addition, it has been well shown that the concrete specimens made of Nano-Silica particles were more impermeable in comparison with other concrete mixes tested in this work. To study the microstructure of the concrete mixes some images were also taken by the scanning electron microscope (SEM), which has shown the ever more uniformity of the samples containing the Nano-particles compared with the control samples. The XRD analysis showed that the Ca(OH)2 amount of such samples is considerably less than that of the control sample.