Potential use of eucalyptus leaves as green corrosion inhibitor of steel reinforcement

Abstract

The use of herbal extracts as green corrosion inhibitors showed many positive aspects such as environmentally friendly, inexpensive and renewable. Eucalyptus trees are forestry that grow with little nutrition in many parts of the world. There is no existing research on the evaluation of Eucalyptus leaves (EL) as green corrosion inhibitors of steel reinforcement. Therefore, this study contributes significantly to the existing knowledge and presents an innovative research to evaluate the effectiveness of EL as a green corrosion inhibitor. In this study, the EL were utilized as coating on the steel reinforcement using four concentrations of 0%, 20%, 30% and 40% by weight of distilled water. Reinforced concrete (RC) beams and prisms were casted and exposed to accelerated corrosion process using an electrical current. The effect of EL on the corrosion of reinforcing steel was evaluated using visual observation, crack pattern and width, ultrasonic pulse velocity (UPV), half-cell potential (HCP), flexural response of RC beams and bond behavior between reinforcing steel and concrete.The experimental results showed that the EL have the potential to be used as green corrosion inhibitors of steel reinforcement. The visual inspection of the corroded RC beams showed that the amount of rust decreased with the increase of EL concentrations. The residual ultimate flexural load of the beams coated with 30% and 40% EL were 95% and 96% respectively compared to 84% for the uncoated beams. The UPV of the corroded aforementioned beams exhibited higher values by 18% compared to the uncoated corroded beams. The HCP test results of the corroded beams coated with 40% EL exhibited lower negative values by 28% compared to the uncoated beams. The corroded prisms coated with EL showed less crack width and attained higher bond-slip performance than the uncoated prisms. The findings of the study are applicable to the concrete construction industry to reduce the corrosion deterioration in the RC structures using EL as an environmentally friendly green corrosion inhibitor compound.