Study of steel corrosion in strain-hardening cementitious composites (SHCC) via electrochemical techniques

This paper investigates corrosion of steel bar in reinforced strain-hardening cementitious composites (R/SHCC) through electrochemical techniques. Linear polarization resistance is engaged to determine corrosion rate of steel bar while electrochemical impedance spectroscopy is employed to study corrosion kinetics by probing the electrode and interface reactions. An equivalent circuit model is used to quantitatively interpret the impedance data of steel corrosion. Results show that polarization resistance Rp of R/SHCC is much higher than that of R/M and thus corrosion rate of steel bar in R/SHCC is much reduced. The Rp of R/SHCC is about two orders of magnitude higher while the corrosion rate of R/SHCC can be two orders of magnitude lower than that of R/M after 137 h accelerated corrosion. Rp of specimen is dominated by the charge transfer resistance Rct before cover cracking and governed by both Rct and cover resistance Rc after cover cracking. R/SHCC specimen possesses a much higher Rct and Rc than R/M due to high tensile ductility and damage tolerance of SHCC material together with tight crack with in SHCC cover.