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What aggregates are used in road construction?

In road construction, aggregates optimally selected for the investment are used. Not only road durability depends on them, but also the safety of their future users. Most often, construction aggregates with appropriate graining and resistance to weather and erosion factors, i.e. resistance to frost, resistance to grinding and abrasion, are used for the construction of this type of investment. Due to their method of obtaining, they are divided into natural and artificial aggregates.

Natural aggregates

The richness and special properties of natural rocks have allowed them to be used for building roads and more for thousands of years. Natural aggregates are of mineral origin, and in their construction form they occur as aggregates obtained from under the water table (gravel aggregates) or mechanical crushing of solid rocks (broken aggregates).

 

The most commonly used natural aggregates include: gravel, grit and the so-called mixtures. Gravel is a sedimentary rock that is an important component in the production of bituminous mass and ready-mix concrete, it is also used to create the foundation of the road. For the construction of the binding, leveling and wearing layers, grit, which is an aggregate that is crushed mechanically, is mainly used.

Artificial aggregates

The second type of aggregates used in road construction are artificial aggregates. They do not occur in nature, and due to the way they are obtained, the following are distinguished:

  • aggregates of mineral originobtained in the processes of thermal treatment or other modifications dedicated to artificial aggregates, e.g. aggregates from steelmaking or blast furnace slag
  • recycled aggregate, going to the "second circulation" thanks to the reprocessing of inorganic raw materials previously used in various industries, e.g.: aggregates from concrete and/or brick construction rubble

To be sure that the selected aggregate meets the requirements of the standards used in the construction industry, and also has the expected parameter values, it is worth carrying out testing of construction aggregates in an accredited research laboratory.