Evaluating the chemical stability and performance of zinc phosphate-coated steel fibers in concrete corrosion simulations

This study investigates the impact of zinc phosphate-coated steel fibers on corrosion performance and bond strength within concrete subjected to corrosive environments. Results indicate that the coating enhanced corrosion resistance in various environments, including saturated Ca(OH), 10 % NaSO, and 3.5 % NaCl solutions. The zinc phosphate coating resulted in a more positive corrosion potential and a lower corrosion rate, likely due to galvanic coupling between the coating and the steel fiber matrix. Furthermore, the improved corrosion resistance in Ca(OH) solution may also be related to the formation of insoluble calcium phosphate compounds. The bond strength and pullout energy in the zinc phosphate-coated fiber-reinforced pre-corrosion specimens enhanced by 19.3 % and 90.92 %, respectively, compared to the bare fiber-reinforced ones. Upon exposure to a simulated seawater environment that induces corrosion, the interfacial bond strength and pullout energy of zinc phosphate-coated steel fibers and cement mortar experienced marginal decreases of 4.2 % and 4.6 %. Zinc phosphate coatings demonstrate considerable promise for extensive application in concrete structures exposed to highly corrosive environments.