Aggregates are the deposits of minerals which are grinded, crushed to attain desired shape and size, thus are not chemically processed. These are widely used in the manufacture of concrete, mortar ; other building materials which are of at most use as far as civil constructions are considered. Earlier these were thought as inert and chemically inactive material which form the bulk of cement concrete but new investigations have revealed that their chemical and thermal reactions impart stability to concrete.
Aggregates are broadly classified as :
1) Fine aggregates
The knowledge of properties (aggregate crushing value, aggregate impact value for coarse aggregates and grain size distribution for fine aggregate) of aggregates is very essential as these form the major proportion of the mix.