Service Life Prediction of Reinforced Concrete Structures Subjected to Corrosion

Abstract

The corrosion of embedded steel reinforcement in concrete due to the penetration of the chlorides from de-icing salts, groundwater or seawater is the most prevalent form of premature concrete deterioration worldwide and costs billions of dollars a year in terms of infrastructure repair and replacement The objective is to predict the service life of already existing structures by suing simple test parameters. It is intended that the developed model will be simple to use for civil engineers with a basic knowledge of concrete durability. Service life of the structure is divided into two stages – initiation stage and propagation stage. The initiation stage is the phase during which the chloride ions penetrate the concrete cover and reach the reinforcing steel in sufficient quantities to de-passivate it, therefore initiating the process of corrosion. The propagation time is the time from corrosion initiation until a specified level of corrosion-induced damage state is attained. A number of models for predicting the service life of concrete structures exposed to chloride environments exist. The approaches adopted by the different models vary considerable and consequently, there can be significant variances between the solutions produced by individual models. Most of the models are complex and sophisticated and have been designed mainly for the research purposes. In the present work an effort has been made to study the service life of RCC structures through experiments wherein, the effect of variation in w/c ratio and diameter of the bars has been studied. It is found that the service life of low w/c ratio and higher diameter bars is found to be more.