Types of asphalt mixes and features of their production

Afaltobeton mixture - a composition consisting of several mineral fillers, selected in such a way as to ensure maximum strength and durability of the resulting coatings. The components most commonly used are crushed stone or gravel, sand, mineral powder (not always), bitumen acts as a binder. There are various types of asphalt mixes, each of which is designed for specific conditions of use.

Types of mixtures и их основные параметры

First of all, all products of this type are divided into groups, depending on which component is used as the main filler, there are gravel, macadam and sand mixtures.

Bitumen of different viscosity is also used, because of this the method of laying may vary:

• Hot asphalt mixes are stacked at a temperature of at least 120 degrees, and both liquid and viscous bitumens are used to produce them.. This option is used for large-scale objects and roads with high loads and heavy traffic, since it can be used to lay a high-quality and durable coating.

• Warm asphalt mixes (many experts call them completely cold) can also be stacked at lower temperatures.. The lower limit of the temperature is 5 degrees Celsius, but it is better to work at 20-30 degrees. At production only liquid bitumen is applied.

Worth remembering! The finished composition should be used within a maximum of 2-3 hours (depending on the brand). Otherwise, the bitumen will harden, and work will become impossible.

Another important factor is the density of the asphalt mix.

You can also subdivide all formulations into fractions:

• If there are inclusions with a diameter of up to 40 mm - coarse.
• For fragments up to 20 mm, fine-grained.
• If the size of the largest blotches does not exceed 5 mm - sandy.

Depending on the amount of rubble present in the composition, the following types of asphalt concrete mixtures are distinguished:

• "A" - this designation says that the content of rubble in the total volume of the composition ranges from 50 to 60%.
• “B” - means that in the finished asphalt composition contains from 40 to 50% of crushed stone aggregate.
• "B" - an abbreviation used to denote compositions in which there is 30-40% of rubble.

Note! Crushed stone for the production of road mixes should have in its composition a certain percentage of fragments of a flat (flaky) shape, the number of such fragments, depending on the brand of the composition, can be from 15 to 35%.

Types of mixtures

All the basic requirements for the compositions, the main characteristics and parameters are set out in GOST 9128-97 "Road asphalt concrete, airfield and asphalt concrete mixtures". All the manufacturers are guided by the norms of this document.

Fine-grained

The most popular and widely used type of materials, most often the following options:

• Dense fine-grained type A grade I, composed of crushed stone fraction from 5 to 20 mm, sand, mineral filler and BND 60/90 bitumen. The strength of the composition determines its widespread use as a top layer on highways, bridges and overpasses. But the price of this option is quite high.

• Fine-grained dense type B is similar in its properties to the above described variant with the only difference that the strength of the coating will be slightly lower, therefore, it is better to use it on roads with medium traffic intensity.
• The fine-grained dense composition of type B grade II, in addition to the components listed in the first paragraph, includes screenings. This reduces the cost of production, but its strength indicators are much less, so it is used for local roads, as well as in yards, parking lots and other similar objects.
• Porous fine-grained mixture is used as the basis for laying more quality options. It can be used almost everywhere, but only as a bottom layer, the top one should always be more reliable options. This option is often used when doing work with your own hands, but the quality of such repairs leaves much to be desired.

Sandy

Grades of asphalt concrete mixes on a sandy basis are used for the following types of work:

• Dense sandy type G and type D is mainly used for parking, sidewalks, floors in garages and hangars, as well as for landscaping yard areas. The composition includes components such as sand, mineral filler and bitumen.
• Another noteworthy species is a highly porous sandy mixture. It is used for places with small loads: footpaths, garden plots, curb molding, and so on. Also, this option is widely used for leveling and warming flat roofs as a base for rolled fusing materials.

Conclusion

Конечно, в рамках небольшого обзора сложно охватить все нюансы, касающиеся смесей для устройства дорожных и других покрытий, это скорее краткая инструкция, позволяющая понять основы данной темы (см.также статью «Железобетонные опоры ЛЭП – особенности и виды данного типа конструкций»).

The video in this article will help to understand some issues in more detail.