From the outset, concrete has been made from the basic components of cement, water and aggregates. The Romans made it from lime, crushed ceramics and volcanic sand (Vitruvius "de Architectura" 1
er
century BC). Rome's Pantheon, built in 124 AD, is covered by a gigantic concrete dome
[1]
.
While the material is plastic and therefore moldable at the time of manufacture, it acquires its properties over time. Once matured, concrete should be considered as a composite of aggregates and a hardened cement paste, whose properties depend to a large extent on its formulation.
Advances in knowledge of the material and new property requirements have prompted researchers and users to introduce new "products" into formulations in order to obtain unique properties. As a result, we are currently witnessing an explosion in the range of concretes available to meet the demands of industry. In return, project managers, taking advantage of their knowledge of these new materials, are proposing innovative structures. This really is a revolution, in that the material is designed according to an ever-increasing number of criteria, and different formulations are therefore defined for each structure.
However, we should be under no illusions: the formulation we develop is usually the result of a compromise that best meets the desired properties. Once the theoretical composition has been established, and very often with the help of experience, it will be necessary to produce and develop the formula in the laboratory, before testing it in an industrial process right up to implementation.
To avoid unsuitable concrete formulations, legislators are increasingly defining formulation limits. The latest European standards with the status of French standards (or, failing that, the French standards in force) will be used as references in this document. In view of the rapid developments in this field, readers are advised to take account of the latest standards in force.