Service life estimation of reinforced cement concrete structure induced by chloride ions

Abstract

Concrete is the most versatile and unique material for building industry. The outcome of the research work carried out by various researches indicates that the service life of the reinforced cement concrete structures can be extended in many ways viz., the use of higher strength concrete, higher concrete cover thickness, use of mineral and chemical admixtures, applying epoxy like coating over the steel and concrete surface, use of corrosion inhibitors, anodic and cathodic protection techniques, etc. This study aims to formulate a method to determine the service life estimation of Reinforced Cement Concrete structures based on the experimental data generated by conducting various durability tests using different grades of concrete with and without mineral and chemical admixtures. The scope of the work involves studying the durability properties such as chloride diffusion, Rapid Chloride Penetration Test, Water Permeability, Resistivity and Accelerated corrosion test for different grades of concretes with and without mineral admixtures to formulate a relationship among the durability parameters for estimating the service life of reinforced concrete. This study also covers the effect of concrete cover thickness, concrete surface coatings, corrosion resistance steel and corrosion inhibitors on durability. From the results of durability study, the constitutional relationship among RCPT, Chloride Diffusion, Water Permeability, Resistivity and Accelerated Corrosion Initiation Time has been formulated. From this co-relation, an equation has been obtained which helps to estimate the service life of reinforced cement concrete structures made with materials of similar to what has been used in the study. Based on this experimental results and co-relationship between durability properties, a model has been developed using MATLAB program to estimate the service life of reinforced concrete structure. The model has been validated with the experimental results carryout on concretes especially for validation and found very good.