EVA enhanced cementitious materials based coatings for the improvement of steel reinforcement corrosion protection performance

Cement-based coatings with higher content of polymers have been demonstrated to provide en-hanced corrosion protection for steel reinforcement, however, they may reduce the bonding strength between steel bars and concrete. In this research, cementitious materials comprising ce -ment, silica fume, and fly ash with weight proportions ranging from 85% to 100% were used as the primary constituents of the cement-based coatings. EVA powder with weight fractions vary-ing from 0% to 15% and nano-silica with contents up to 1% are added to the coating formulation to promote coating performance. The results of electrochemical tests including linear polariza-tion resistance and electrochemical impedance spectroscopy show that addition of EVA powder, silica fume, and nano-silica can substantially increase and decrease the coating resistance and corrosion current density of the coated steel bar, respectively. When 15% EVA, 1% silica fume and 0.5% nano-silica are added to the coating formulation, the coating can provide the best anti-corrosion performance for the steel bar. The integrated polymer film shown in the SEM image and the undetected chloride ions at the vicinity of the coated steel bar obtained from EDS analysis also demonstrate the excellent protective performance of the cement-based coating against corro-sion.