Analysis of the Loss of Steel-Concrete Bond Due to the Migration of Ions

Abstract

In this work, the degradation of bond between steel and concrete under cathodic protection conditions (-1000mV≤ E ≤ -850mV vs. Ag/AgCl) and cathodic overprotection ((E < -1000 mV vs Ag/AgCl) by impressed current applied in two mixtures submerged in a solution of 3.5% wt. NaCl was evaluated; the first fabricated from ordinary Portland cement (OPC) and the second by substituting 15% of the cement with fly ash(OPCFA). According to the results of chemical analysis and Electrochemical impedance spectroscopy on the steel-concrete interface, was found an increase in the concentration of potassium, sodium (K+, Na+) and hydrogen (H+) ions . In addition, was observed that for specimens subjected to overprotection presented a higher bond loss, this based on pull out test results also realized.