When reinforced concrete was invented in XIX Century, durability was not considered a concern at all, because the degradation processes affecting this material were still totally unknown and unforeseen. The concept of concrete durability was born just some decades ago, from the appraisal of the frequent and severe defects affecting concrete structures, and is now included in the basic requirements for structural concrete, hence it’s put at the same level of compressive strength by most of national laws. Durability is conventionally defined as the capacity of concrete to resist to environmental attack for a service life of 50-100 years (depending on the different standards) without any need of extraordinary repair works. Durability is to be achieved according to the specific place where the concrete structure will be located. i.e. in relation to the specific local environmental aggressions (the so called “environmental exposure classes”).
