Synergistic inhibition effect of Polyacrylamide and Tetradecylpyridinium bromide on corrosion behavior of carbon steel rebar in simulated cement-mortar pore solution

Synergistic inhibition effect of Polyacrylamide (PA) and Tetradecylpyridinium bromide (TTAB) on the corrosion behavior of carbon steel rebar in simulated cement-mortar pore solution was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The EIS results revealed that the PA as a mixed-type inhibitor considerably enhanced corrosion protection performance in carbon steel rebar with creation of an organic layer to prevent both cathodic and anodic corrosion reactions. The obtained electrochemical results show that the inhibition efficiency of PA was significantly enhanced in the presence of TTAB for carbon steel rebar which confirms the synergistic corrosion effect between TTAB and PA. Because the inhibitor type changed from mixed-type to anodic-type through the increase of TTAB concentration, they eventually delayed the anodic dissolution of carbon steel which reduced the corrosion rate of the steel rebar in an aggressive environment.