Aggregates are a broad category of materials, granular raw particle minerals,used in constructions and can be natural, artificial or recycled from materials previously used in construction.
The aggregates include sand, gravel, expanded clay, vermiculitis and perlite.
Aggregates are used in construction primarily as components of composite materials, such as cement conglomerates (for example concretes), oil conglomerates (e.g. asphalteons) and plasters .
They also form the skeleton of the conglomerate, whose cohesion is guaranteed by cement paste or bitumen or lime.
From a quantitative point of view, aggregates are very important, since in the mass of an ordinary concrete they represent about 80% of the weight.
For the success of a conglomerate is fundamental, in addition to the quality of aggregates (determined among other things by their hardness and their purity), also the grain composition (grain curve of aggregates).