Influence of a Superplasticizer on Initial Corrosion of Galvanized Steel Bars in Concrete Pore Solution

Abstract

In this work, the influence of a naphthalene sulfonate–based superplasticizer on the initial corrosion of galvanized steel bars in the simulated concrete pore solution was studied. The initial corrosion process of the galvanized steel in solution with superplasticizer was first monitored. The inhibition effect of the protective layer formed by the superplasticizer and the protective property of the calcium hydroxyzincate (CHZ) passive layer were defined. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS) was used to observe the surface morphology of the CHZ passive layer. The results showed that the addition of superplasticizer delayed the initiation of the corrosion process of galvanized steel bar and inhibited the hydrogen evolution. The protective property of the CHZ layer on galvanized steel varied with the concentration of superplasticizer. The inhibition effects of the superplasticizer on the initial corrosion will be beneficial to the quality of the steel–concrete interface.