TY - JOUR
T1 - Chloride-induced corrosion of steel rebars in simulated pore solutions of alkali-activated concretes
AU - Mundra, S.
AU - Criado, M.
AU - Bernal, S.A.
AU - Provis, J.L.
PY - 2017/10/31
Y1 - 2017/10/31
N2 - The passivation and chloride-induced depassivation of steel rebars immersed in varying alkaline environments (0.80 M, 1.12 M and 1.36 M NaOH solutions), simulating the pore solutions of low-Ca alkali-activated concretes, were investigated using a range of electrochemical techniques. The passive film on the steel rebars was complex in chemical makeup, composed of Fe–hydroxides, oxy-hydroxides and oxides. An increased degree of passivation of the rebars was observed when exposed to solutions with higher hydroxide concentrations. The critical chloride level ([Cl−]/[OH−] ratio) required to induce depassivation of steel was strongly dependent on the alkalinity of the pore solution, and was found to be 0.90, 1.70 and 2.40 for 0.80 M, 1.12 M and 1.36 M NaOH solutions, respectively. These values all correspond to a constant value of [Cl−]/[OH−]3 = 1.25, which is a novel relationship to predict the onset of pitting, interlinking chloride concentration and the solubility of the passive film.
AB - The passivation and chloride-induced depassivation of steel rebars immersed in varying alkaline environments (0.80 M, 1.12 M and 1.36 M NaOH solutions), simulating the pore solutions of low-Ca alkali-activated concretes, were investigated using a range of electrochemical techniques. The passive film on the steel rebars was complex in chemical makeup, composed of Fe–hydroxides, oxy-hydroxides and oxides. An increased degree of passivation of the rebars was observed when exposed to solutions with higher hydroxide concentrations. The critical chloride level ([Cl−]/[OH−] ratio) required to induce depassivation of steel was strongly dependent on the alkalinity of the pore solution, and was found to be 0.90, 1.70 and 2.40 for 0.80 M, 1.12 M and 1.36 M NaOH solutions, respectively. These values all correspond to a constant value of [Cl−]/[OH−]3 = 1.25, which is a novel relationship to predict the onset of pitting, interlinking chloride concentration and the solubility of the passive film.
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85027856693&partnerID=MN8TOARS
U2 - 10.1016/j.cemconres.2017.08.006
DO - 10.1016/j.cemconres.2017.08.006
M3 - Article
SN - 0008-8846
VL - 100
SP - 385
EP - 397
JO - Cement and Concrete Research
JF - Cement and Concrete Research
ER -