Study the Effect of SiO₂ Nanoparticles as Additive on Corrosion Protection of Steel Rebar in Artificial Concrete Solution

Abstract

It well known the advantages of using SiO 2 nanoparticles as additive for improving the mechanical properties of concrete structure and reducing the liberation of CO 2 gas to the atmosphere. This research investigate the effect of adding SiO 2 nanoparticles (12 nm; 1, 3 and 5% by weight) to artificial concrete solution (2gCa (OH) 2 , 0.0225 g KOH and 0.008 g NaOH in one litter of distilled water) on the corrosion of steel rebar against seawater environment (3.5% NaCl) at four temperatures; 20, 30, 40 and 50°C. The corrosion parameters and pitting probability of the carbon steel rebar were measured in separate experiments using Tafel plot and cyclic polarization procedures, respectively. The corrosion protection efficiency was increased with increasing SiO 2 content and values of 37-80% were recorded in comparison with the concrete solution free of SiO 2 NPs. The cyclic polarization voltagrams show that the SiO 2 NPs reduces the pitting area in all SiO 2 concentrations and fully stopped the pitting problem because of the chloride ions. The surface morphology of the steel rebar was examined before and after polarization using Atomic Force Microscope (AFM).