Coconut coir dust extract (Ccde) as green corrosion inhibitor for rebar’ steel in concrete environment

Corrosion of reinforcement steel in concrete is one of the drawbacks of reinforced concrete structures. An attempt is made to use Coconut Coir Dust Extract (CCDE) as a green corrosion inhibitor. The efficacy of the CCDE is examined in simulated concrete pore solutions and in concrete structures. The influence of CCDE on the inhibition of corrosion of steel in concrete has been evaluated by non-electrochemical and electrochemical techniques. The various concentrations of CCDE (0%, 10%, 20%, 30% and 40%) in simulated concrete pore solution (SCPS with 3.5% NaCl) were studied by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy. The addition of CCDE up to 40% did not affect the mechanical property of concrete. It is observed that CCDE was able to provide more than 95% inhibition efficiency in SCPS with 3.5% NaCl solution. The mechanism of inhibition is due to adsorption and, thereby, film formation on the steel surface. Potentiodynamic polarization studies indicated that CCDE act as a mixed type inhibitor and predominantly cathodic. CCDE is a good candidate greener inhibitor for corrosion of steel in concrete because it increases the compressive strength of concrete and reduces the self-corrosion of steel rebar in chloride environment to the maximum extent.