Pre-treatments in silicate solutions to mitigate reinforcing steel corrosion in chloridecontaminated environments

A.C. ROLANDI; F. MONTES; L. MORAN AYALA; M. A. FRONTINI; VAZQUEZ M.; M.B. VALCARCE

CORROSION ENGINEERING, SCIENCE AND TECHNOLOGY

MANEY PUBLISHING

Lugar: London; Año: 2022

1478-422X

Silicate ions were incorporated into a pre-treatment to mitigate corrosion in concrete reinforcing steel bars (rebars). The efficiency of these pre-treatments with and without silicate ions present was compared by testing steel samples in concrete pore simulating solutions contaminated with chloride ions. The study involved cyclic voltammetry, anodic polarization curves, and weight-loss tests following a 60-day immersion period. Surface analysis included micro-Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The electrical properties of the film were analyzed by impedance spectroscopy and Mott-Schottky plots. Polarization curves show higher pitting potentials and lower corrosion current densities when silicate ions are present during pretreatment. Localized attack is observed after 60 days of immersion in solutions containing chloride ions, but weight loss is reduced by 75% for coupons pretreated in silicate solutions. XPS and Raman spectra indicate that the presence of silicate ions affects the composition of the passive film and the corrosion products, increasing the proportion of Fe(II) species. The results show that pre-treatments in silicate solutions can be effective to minimize rebars? corrosion in aggressive environments that simulate concrete contaminated with chloride ions.