Fluoride induced corrosion of steel rebars in contact with alkaline solutions, cement slurry and concrete mortars

摘要

Corrosion behaviour of mild steel rebars has been studied in contact with 0.01 N NaOH, saturated lime water, cement slurry and embedded mortars having different concentrations of fluoride ions. Weight-loss, electrochemical DC cyclic polarization and polarization resistance, surface topographic and X-ray diffraction (XRD) techniques have been used to investigate the effects of fluoride ion on the corrosion behaviour of the material. Under all the conditions of the exposure it is observed that a low content of fluoride (≤25 ppm) in the corrodent has deleterious action on the performance of the steel where as at its higher content (≥100 ppm) the ion has rather an inhibiting effect on corrosion rate.