Investigating the synergistic effect of Nano and Micro silica on porosity of cement mortar by FE-SEM image analysis

In recent years combined usage of the supplementary cementitious materials especially Ns and MS has become a popular topic. The aim of this study is to investigate the synergistic effect of nano- and micro-silica on the porosity of the cement mortar by using FE-SEM images. Therefore, 12 mix designs with different amounts of nano- and micro-silica with two W/B ratios have been considered. Also, FE-SEM images were taken from the control specimen, and the best mixtures in the form of Ns alone, Ms alone, and combined Ns and Ms. Consequently, a comparative investigation was carried out to evaluate the effect of different percentages of nano- and micro-silica on the porosity and microstructure of cement mortar. The results show that the addition of nano- and micro-silica gradually decrease porosity and improves the microstructure of the specimens. nevertheless, simultaneously usage of them leads to the lowest porosity values and the most compact microstructure. Also, The microstructure observations have been confirmed the experimental porosity results.

کلیدواژه ها:

Cement mortar ، Nano silica ، Micro silica ، Porosity ، Microstructure