Any asphalt concrete mix consists of mineral materials: bitumen, sand, crushed stone, and gravel. The durability of the final mixture largely depends on the quality of the binding bitumen. Superpave technology assumes an accurate selection of bitumen not according to outdated standards, but according to a specially created PG Grade scale. The PG classification helps to determine the bitumen binder suitable for a particular road section. The choice of bitumen depends on:
- features of natural conditions;
- density of load during automobile traffic;
- the highest summer and winter temperatures in the last 20 years.
Indicators used to evaluate the parameters of the binder are:
- density;
- plasticity;
- dynamic viscosity;
- creep resistance.
The compliance of these parameters is checked during laboratory tests.