Increasing of the cement strength and corrosion resistance of rebar inside it using silica nanoparticles

In this work, silica nanoparticles were added to the mortar with one percent by weight of cement. To investigate the effect of these nanoparticles on the strength of cement, 7-day and 28-day strength according to ASTMC109 standard was obtained and compared with the results of the control sample. the results showed that these nanoparticles increase the compressive and bending strengths. To investigate this nanoparticles effect on the corrosion resistance of the rebar inside the cement, polarization and EIS tests were performed in 3.5% salt solution.The results of the polarization test showed that the sample with silicon dioxide nanoparticles has more corrosion potential and less corrosion current, which indicates less corrosion rate and less corrosion tendency of this sample compared to the control sample. EIS analysis showed that samples with the presence of silicon dioxide nanoparticles have higher electrical impedance than the other. By simulating the equivalent circuit, the reason for the higher electrical impedance of the mortar in the presence of Sio2 nanoparticles was investigated.The results showed that the reason for the increase in corrosion resistance and electrical impedance is the increase in electrical resistance, increase in ion diffusion and the decrease in capacitance of mortar.