FAQ >> Types of asphalt pavements and asphalt grade

Types of asphalt pavements and asphalt grade

There are two types of asphalt or concrete surfaces - asphalt concrete and Tarmacadam in road construction. Concrete - an artificial material made by compacting a specially selected mixture of gravel, sand, mineral powder, bitumen or tar and pitch. I. Asphalt concrete. Depending on the temperature at which the stack and seal the mixture in the coating, and viscosity of the bitumen used distinguish the following classes of asphalt concrete:

  1. Hot, prepared against the viscous bitumen at 140-180 ° C and fits into the coating at a temperature below 130 ° C, the formation of the concrete structure is basically completed during the sealing, hot tarmacadam during installation must have a temperature of 80-110 ° C;
  2. Warm - made ready for the bitumen of reduced viscosity at a temperature of 90-160 ° C and fits into the coating at a temperature of 30-100 ° C, the formation of the structure also results in the period of seal
  3. Cold, prepared against the liquid bitumen at a temperature of 80-120 ° C and put into treatment after their full cooling, the formation of their structure lasts for 20-30 days. For cold asphalt mixes are also on the bitumen emulsions which are laid at normal temperatures.
On the maximum size of grains of the mineral material, asphalt concrete is divided into:
  • Coarse-grained with the largest grain size of 40mm;
  • Medium-- 25mm;
  • Fine - 15mm; br <> - Sandy - 5mm.
On structural characteristics (density), asphalt concrete can be:
  • Dense, having a total porosity of 3-5% in volume;
  • Macroporous with a porosity of 5-10% volume.
In construction practice, along with the hot, warm or cold asphalt concretes are also used cast asphalt. Condense it into the hot iron or a light (0,5-1,5 m) wheels. Mastic asphalt use in cramped conditions, where you can not use heavy rollers and vibrators or small volumes of papers (for a device coating on the sidewalks, flat roofs, floors in warehouses and industrial buildings, as well as for waterproofing). II. Tarmacadam is a material similar to asphalt concrete. The binder is used for its manufacture coal tar marks from the D-5 to D-8, or tar, consisting of coal tar pitch, coal oil and crude tar. Tarmacadam laid in the hot and cold. Depending on the size of rock material, tarmacadam subdivided into large, medium and fine. To prepare the hot tarmacadam used the same mineral materials, as for asphalt and requirements are similar to them. Tarmacadam mixture is prepared in the asphalt plant at a temperature of 100-130 ° C, the temperature of the mixture at issue - 100-120 ° C. tarmacadam have less water resistance, durability and resistance to heat than asphalt and less flexible, so the more deformed in the cold. Tarmacadam roads used for Category III for repair. However, the preemptive use asphalt instead of tarmacadam.

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