Almost every type of asphalt concrete consists of the following components:
- mineral powder, which is made from limestone and other organic deposits.
Depending on the proportions of these components, asphalt is usually divided into three grades, according to GOST 9128-2009:
- I – the composition includes screening or sand, crushed stone, mineral powder, bitumen. This grade is divided into dense asphalt mixtures A, B, D, high-density, high-porosity crushed stone (hot and cold), Bx, Bx, Gx and porous.
- II – sand, bitumen, crushed stone, mineral powder, crushing screenings. Types: highly porous sandy, dense A, B, C, D, D, porous, Bx, Vx, Gx, Dx.
- III – screening of crushing, mineral powder, bitumen, sand. Types: dense B, C, D, D.
As for the letter designations, they help determine how much crushed stone or sand is contained in the asphalt:
- A – crushed stone about 50-60%.
- B – gravel or crushed stone 40-50%.
- B – gravel or crushed stone 30-40%.
- D – maximum sand content from crushing screenings is 30%.
- D – up to 70% of the content of natural sand or a mixture of natural sands with crushing screenings.
Depending on the maximum grain size of the mineral components contained, the asphalt mixture can be:
- Fine-grained. The particle size in this case ranges from 5 to 15 mm. The surface is especially flat and smooth. Such asphalt is often used on sports grounds and adjacent areas..
- Medium-grained. The particle size is 25 mm on average. Ideal for squares and city streets.
- Coarse-grained. The grains can be up to 40 mm. This mixture is used on suburban roads, where heavy vehicles often drive..
As for the types of asphalt, there are two main ones:
Cold. In fact, it is warm, the temperature can be about 80 ° C. It is an all-weather mixture used for highway repair. Cold asphalt, which can be used at low temperatures, is easier to work with, no special equipment is needed. Cold asphalt is stored and transported in bags and simply poured into a pit, from which all dirt was removed and the edges were processed. Cold asphalt is compacted, and then sprinkled with sand or cement dust so that the mixture does not stick to the wheels of passing cars.
Hot asphalt. Its temperature exceeds 120 ° C, therefore, special equipment, a skating rink is needed, and the mixture itself is delivered to the paving site by dump trucks and literally poured onto the highway. While cold asphalt is usually used for patching, hot asphalt is used specifically for road construction or major repairs..
In Europe, it is now widespread cast asphalt. In Russia, it is used much less often, since special equipment is required for laying, and the coating itself is more expensive. Meanwhile, cast asphalt has a lot of advantages, despite the fact that its composition practically does not differ from the usual one. Thanks to the special paving technology, the cast asphalt allows you to carry out all the work faster. The cast asphalt is heated up to 250 ° C, it is very fluid and evenly distributed on the surface on its own, that is, the roller is not needed. In addition, cast asphalt is harmless, durable, resistant to deformation, and is used all year round..
Among other types of asphalt pavement can be distinguished color mixture. This is a very convenient way to highlight stops, bike paths, parking lots, pedestrian zones and other areas. In colored asphalt concrete mixture, clarified bitumen is used together with a coloring pigment.
Also stands out rubber asphalt. As the name implies, it contains rubber additives that prevent water from entering the asphalt area. Stronger, more durable, rubber asphalt proves to be more expensive due to additional additives.
There is also plastic asphalt, which is becoming more and more popular due to the low cost of production and other characteristics. Up to 20% recycled plastic is added to this mixture. There is also sulfonated asphalt used in the drilling industry, recycled, that is, created from the already used coating, sandy for sidewalks and footpaths, natural, made from oil and containing up to 50% oils.
Liquid or soft asphalt is often used to equip the floor in industrial premises..
The special paving technology also makes it possible to create stamped asphalt that looks like paving slabs or bricks and has an attractive appearance. To create stamped asphalt, it is heated with special infrared equipment until it becomes plastic. Then they give the desired shape with metal flexible stamps, primer, clean the surface and then apply a coloring wear-resistant polymer composition.