From prescription to performance: international trends on concrete specifications and the Brazilian perspective

There are two types of specifications: prescriptive and performance based. The prescriptive specifications focus on materials properties, materials proportions, mixing and transporting procedures and on a variety of processes, such as placing and curing. In these specifications, the concrete desired performance it is not necessarily described. On the other hand, performance specifications stipulate what is required from the product and do not prescribe how the product should be produced. In other words, they focus on the desired performance rather than on the concrete ingredients, materials selection, proportioning or construction methods. These are the responsibility of those individuals who contractually have to comply with the specifications. In this case, con- crete is defined in terms of measurable fresh and hardened properties and durability and as there are no restrictions regarding materials and their proportions in the performance specifications, innovative solutions may be used in order to achieve the performance requirements. Currently, most concrete specifications are predominantly prescriptive with some performance requirements. Nevertheless, there is a consensus that in order to extend the service life of concrete structures, this has to be changed. This paper gives an overview of the international specifica- tions and describes the international efforts on the performance specification implementation in the concrete industry.