Materials such as sand, gravel, and crushed stone used in concrete production are generally referred to as aggregates. Aggregates are a significant component of concrete, occupying about 60–75% of the total volume.
Aggregates are divided into two types:
Fine aggregates (e.g., sand, crushed sand)
Coarse aggregates (e.g., gravel, crushed stone)
The main desired properties of aggregates are:
They should be hard, durable, and non-porous
They should not contain weak particles (such as seashells, wood, coal pieces, etc.)
They must be resistant to compression and abrasion
They should be free from dust, soil, and other harmful substances that can negatively affect the concrete
They should not contain flat or elongated particles
They must not exhibit alkali reactivity
To ensure consistent quality in concrete aggregates, tests such as sieve analysis, shape index, specific gravity, and water absorption should be conducted regularly.
