Aggregate - Types of aggregates

Definition:

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.

Coarse Aggregate

Those particles that are predominantly retained on the 4.75 mm (No. 4) sieve, are called coarse aggregate

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 aggregate

Purpose & Uses

1. Increases the volume of concrete, thus reduces the cost
2. Provide dimensional stability
3. Influence hardness, abrasion resistance, elastic modulus and other properties of concrete to make it more durable, strong and cheaper.