Aggregate; Natural, artificial or dense mineral materials of both types, usually up to 100 mm in various sizes - unbroken, mineral materials such as gravel, stone, or solid materials such as mortar, asphalt or concrete when these materials come together and bonded with a binder are mixtures that create substances.
When we look at the dictionary meaning, it is called aggregate for fractured or unbroken, artificial or natural, dense mineral materials of different sizes. Aggregate; natural, artificial or dense mineral material of both sexes, generally of unbroken mineral materials such as gravel, stone of various sizes up to 100 mm or when these materials come together to form a solid material such as mortar, asphalt or concrete when connected with a binder. mixtures.
Among the aggregate types, sand and gravel are the most commonly used materials. Pebbles are among the most widely used natural aggregate types in construction. However, instead of pebbles, crushed stones, which are obtained by the disintegration of natural stone masses by using machines, are also used as aggregates. Where natural sand is needed, artificial fine aggregates are obtained by using grinding machines.
One of the main features of the aggregate is that it has a solid structure, is not easy to wear, is not soft and does not disperse in contact with water. When using aggregate, it is necessary that when combined with cement components, it does not form a harmful compound and that it is not dangerous to protect the place where it is used against abrasion. In addition, the texture and shape of the aggregate grains are expected to be good and the distribution of the grains is expected to be in accordance with the intended use and standards. And, of course, there should be no other harmful substances in the aggregate.
The factors that determine the physical properties of the aggregate are: unit weight, density, capacity of the aggregate, ie the size of the volume occupied by the grains in the unit volume, resistance to freezing and thawing of the aggregate, and the nature of the voids between aggregate grains. In addition, the factors determining the mechanical properties of the aggregate are: the pressure resistance of the aggregate, its abrasion resistance and impact resistance.
Aggregate is one of the most important materials in concrete construction. Aggregate diversity, compressibility and granulometry (ie, to what extent aggregate is used) affect the class of concrete. in a simple way, the aggregate is a mixture of sand, gravel and crushed stone, and the diameter up to 4 millimeter is sand and the up to 32 millimeter is gravel. Aggregate is obtained by blending these materials and is used to create concrete formation in structures. In some cases it is also used as a filling material.
With these properties, aggregates are two types as natural aggregate and artificial aggregate. Natural aggregates are generally obtained from river beds, sea coasts and sand quarries. Aggregate has a wide range of usage from road and tunnel constructions to all kinds of constructions.
Aggregate tests are performed in authorized test and inspection laboratories. During these tests, the current regulations and published standards are taken into consideration. The following are a few standards for aggregate testing:
- TS EN 1097-6 Tests for mechanical and physical properties of aggregates - Part 6: Determination of grain density and water absorption rate
- TS EN 1744-7 Tests for chemical properties of aggregates - Part 7: Determination of combustion loss of aggregate (MIBA aggregate) in municipal ash incinerator
- TS EN 933-1 Tests for geometric properties of aggregates - Part 1: Determination of particle size distribution - Screening method
- TS EN 933-7 Tests for geometric properties of aggregates - Part 7: Determination of shell content in coarse aggregates - Percentage of shell
- TS EN 932-5 Tests for general properties of aggregates - Part 5: General instruments and calibration
- TS EN 1355 Gas concrete or lightweight aggregate porous concrete - Determination of creep under pressure
