Effect of areca catechu extracts as green corrosion inhibitor on concrete properties

Abstract

The most significant reason of failure in reinforced concrete structure worldwide is corrosion of reinforcement. Presently a great tendency has been shown on preventing reinforcement corrosion by means of corrosion inhibitors. In addition, studying the effects of inhibitors on concrete properties despite of corrosion aspect could have significant impact on engineering use of them. Therefore, the aim of the present research was to evaluate the performance of environment friendly green plant namely, Areca Catechu extracts inhibitor additions to contaminated concrete containing 5% magnesium sulphate and sodium chloride with water cement ratio of 0.55 in simulated tropical climate. Areca Catechu (Areca Catechu leaf extracts) inhibitor was selected through screening of five green plants extracts, namely; Acacia Longifolia (Acacia), Areca Catechu (Areca Palm), Elastoma Malabathricum (Indian rhododendron), Elaeis Guineensis (Oil Palm) and Cocos Nucifera (Coconut), and two chemical commercial inhibitor namely, Triethanolamine and natrium nitrit. As a result, Areca Catechu was selected due to its high efficiency and high content of potassium. Accordingly, Areca Catechu effectiveness as green inhibitor was compared to natrium nitrit as chemical inhibitor. The specimens were subjected to various tests in order to study fresh, physical, mechanical, chemical, permeability, durability and microstructural properties of contaminated and inhibitor-added concrete. From the results, Areca Catechu exhibited high inhibition efficiency and acceptable adsorption characteristics. In addition, the green inhibitor-added concrete produced acceptable compressive, tensile and flexural strength, low permeability proved by water absorption and ISAT test, and exhibited lowest corrosion rate, lowest double layer capacitance (Cdl), highest concrete resistivity and also highest polarization resistance (Rp) values for the entire period of exposure, compared to natrium nitrit. In conclusion, Areca Catechu exhibited a good substitute for chemical and toxic corrosion inhibiting admixtures for durable concrete constructions due to its hydrophobic effects, availability, viability, versatility and eco-friendliness.