Aggregate, Types of aggregates:- Aggregate is a granular material, such as sand, gravel, crushed stone, crushed hydraulic-cement concrete, or iron blast-furnace slag, used with a hydraulic cementing medium to produce either concrete or mortar. Aggregate is used Coarse Aggregate:- Those particles that are predominantly retained on the 4.75 mm (No. 4) sieve, are called COARSE AGGREGATES. Fine Aggregate:- Those particles passing the 9.5 mm (3/8 in.) sieve, almost entirely passing the 4.75 mm (No. 4) sieve, and predominantly retained on the 75 µm (No. 200) sieve are called FINE AGGREGATES.