Types of aggregates
These are of the following types.
These are further divided into:
- Coarse graded.
- Fine graded.
Those which retain on sieve # 4 are known as coarse aggregates.
Coarse graded consists of continuous grading of sizes. But mainly it consists of coarse sizes. A coarse aggregate of uniform size known as macadam, received its name from a Scottish engineer John Macadam. He first used it in asphalt mix.
Those which passes through sieve # 4 and retain on sieve # 200 are the fine aggregates.
Fine graded have a predominance of fine sizes.
Those which even passes through sieve # 200 are known as Filler.
To achieve special strength, we make special aggregates which are known as artificial. These are used to gain high strength. As naturals have not enough strength.
Those which breakup due to single jerk are known as soft. For example shale.
Those which do not breakup on a single jerk are known as hard. For example granite.