Durability design of concrete structures with corrosion resistant reinforcement

Under chloride bearing environment or when a long service life is required, corrosion resistant steels can be used for the design of reinforced concrete (RC) structures. The benefits gained with their use, in terms of increase in the service life, can be quantified by means of performance-based approaches. However these approaches are seldom used for the design of RC structures. This is in part due to the lack of knowledge of designers of recently proposed models and, in part, to difficulties in defining proper values for some of their parameters. This paper analyses some critical aspects of these approaches, with particular regard to the fib Model Code for Service Life Design, in the presence of corrosion resistant steel reinforcement. Furthermore it provides a contribution for the identification of possible options for the durability design of concrete elements with corrosion resistant bars exposed to marine environments. On the basis of a literature survey, reasonable values for the critical chloride threshold of reinforcement different than ordinary carbon steel are proposed. However, due to the difficulties in defining proper values of this parameter for this type of bars, the need for the development of a compliance test for its measurement is highlighted.