Abstract
This work investigates the possibility of improving the corrosion resistance of reinforced concrete against corrosive mediums mainly represented by chloride and sulfate ions by using polyaniline (PANi) coating. The polyaniline layer was formed using the galvanostatic technique and investigated for its composition by using X-Ray Photoelectron Spectroscopy (XPS). The potentiodynamic technique was used for investigating the corrosion resistance of the PANi coated steel while coupled with stainless steel and used for reinforcing a layer of concrete, containing different concentrations of corrosive materials such as NaCl and H2SO4 the corrosion current was measured against Ag/AgCl reference electrode. The main variables investigated were the initial concentration of both Cl- and SO4-2 and the time interval from 0 to 28 days (initial hardening period). The results showed that using polyaniline coating has improved the corrosion resistance of reinforced concrete against Cl- by a factor ranging from1.10 to 1.90 and by a factor ranging from 1.30 to 1.60% against SO4-2 of its value compared to uncoated steel depending on initial concentration of Cl- and SO4-2 respectively. In addition the results showed that Cl- is superior to SO4-2 in causing corrosion of steel. The corrosion rate of steel subjected to Cl- ions is higher than that of SO4-2 by a factor of 1.688 and 1.815 for both bare and polyaniline coated steel respectively.