Predicting the service-life of concrete structures – Limitations of simplified models

North American civil infrastructure systems are deteriorating. Roads, bridges, overpasses, marine and airport facilities are all impacted. The primary causes of premature concrete deterioration are harsh climatic conditions and chemical attacks, particularly exposure to winter de-icing salts and seawater. Given the growing concern for concrete degradation, numerous computer-assisted tools have been developed to assist engineers in the prediction of the service-life of structures. Many of these models are based on simplified equations that significantly restrict the scope of their application. The limitations of these approaches for the design of new construction and rehabilitation of existing structures are discussed. The theoretical assumptions at the basis of these models are first reviewed. Special attention is paid to the consequences of these simplifying assumptions on the reliability of the models. The difficulties of using these simplified models for the treatment of actual structures exposed to natural conditions are then discussed.