What is the type of asphalt concrete: the composition of the
Asphalt concrete is used everywhere to build roads and improve the area, which guarantees the quality and durability of the pavement. It consists of road bitumen and a mixture of natural minerals. Each type of asphalt concrete is used in different cases, so let's talk about it below.
Minerals provide high strength coating, and bitumen acts as a binder, the price of the mixture depends on the quality of the materials used in it. The styling technology is the same all over the world, but the quality depends on modern additives. As you already understood, asphalt and concrete are present in the basis of the mixture we are considering.
The composition of the asphalt mixture
Quantitative, qualitative and fractional composition will determine the GOST 9128-2009. It includes gravel and rubble, which is crushed to such an extent that it resembles crumb. Sand is also added there; bitumen is a resinous product, which, like all resins, is characterized by binding properties only in a heated state.
Note! In a small amount of asphalt can be laid with his own hands.
Note! Asphalt mix is always laid hot.
However, a technology has been developed that allows obtaining bitumen of a viscous consistency at a temperature of + 5 ° C. Today's methods of oil refining allow to obtain this material, which does not freeze at temperatures up to -30? С. If warm asphalt is used, it can be operated at a temperature of -5? С.
According to the content of mineral substances, asphalt concrete mix can be classified into several groups:
- A - contains 50-60% gravel or crushed stone;
- B - contains 40-50% gravel or crushed stone;
- B - contains 30-40% gravel or crushed stone.
The size fraction of crushed stone or gravel is determined by TU-5718.030.01393697-99. Guided by the technical conditions, crushed stone 10-20 mm in size is added to the mixture of asphalt concrete for laying as the top layer of the road surface.
The technology is considered standard and has found application everywhere, but it depends on the load and the complexity of the operating conditions which polymers and surfactants will be added to it.
Kinds
Consider what happens asphalt and where it is used:
| Sandy | Designed for: · patching of sidewalks and pavement (in winter and spring); · pouring cracks; · waterproofing; · roofs. |
| Fine-grained | The instruction recommends using the material to create the upper layer: · access to houses, car parks, · roadway with small and high intensity, · leveling the bases. |
| Coarse-grained | Designed for the manufacture of the lower layer of the roadway. |
| Drainage | It has a porous structure and is used for quick removal of rain moisture from the roadway. It is usually laid as a new layer for the already repairable old. |
Cast asphalt concrete
Modern technologies have made their adjustments to the composition of the asphalt mixture. Every year, the load on the pavement increases, which triggered a search for new components that could improve its performance.
The result of this work was the emergence of cast asphalt, which is used both for laying new roads, and for repairing already operated ones. The developed technology is determined by GOST 54401-2011 and involves laying the road surface without rolling (compaction).
The temperature of the mixture should correspond to 190? С; the higher the temperature, the more flexible it is. This composition is characterized by good plastic properties due to the polymer components.
The composition of the cast asphalt includes a greater amount of bitumen and polymer additives, the volume of minerals, respectively, reduced. The amount of crushed stone for concrete, up to 5 mm in size, can vary from half the mass to zero. The mixture is characterized by the smallest possible granularity, with the result that it has a viscous consistency, which does not require compaction at all.
Due to the bitumen polymer binder improved physical properties.
The top layer of the pavement of molded asphalt concrete is typical:
- high strength;
- wear resistance;
- integrity;
- long service life without pits and cracks.
The process of laying roads using this technology requires very precise observance of proportions and conditions. This is the only weak spot of the cast asphalt concrete, failure to comply with the norms leads to deterioration of the strength characteristics of the concrete pavement.
Making pavements, sidewalks, playgrounds
Another advantage of the cast coating is decoration, which significantly expands the possibilities of its use:
- sidewalk decoration;
- tracks;
- alleys
On the roadway, colored asphalt concrete is used for marking - a pedestrian crossing, dividing lanes. The decorative effect is obtained by corrugation, embossing, interfering with colored minerals.
Technology staining allowed to add to the composition of minerals:
- colored crushed stone, size up to 5 mm;
- sand from limestone, granite, clinker, marble;
- color pigments: zinc white, chromium oxide, crowns, red lead;
- bitumens clarified and synthetic - to get a lighter coating.
This technology increases the cost of coverage, so it is rarely used, another method has become common:
- The color chips are mixed directly into the coating during asphalt laying, and not mixed with all the components at the initial stage.
- The baby is present only in the upper layer, which results in maximum coloring and cost reduction of work.
Conclusion
Various types of asphalt concrete make it possible to apply the material strictly for its intended purpose. The result is a coating that serves for a long time without major repairs. This article has reviewed several major types of asphalt concrete. The video in this article will help you find additional information on this topic.