Historical facts related to asphalt. What is asphalt? When to use cold and hot paving of asphalt

Asphalt is a mixture mineral materials(gravel and sand) and bitumen. In the depths of the Earth it can be in both liquid and solid form. As the temperature rises, it softens and becomes liquid, and when the temperature decreases, it hardens again. Asphalt contains carbon and hydrogen, the latter, in turn, is part of crude oil.

Types of asphalt

There are two types: natural, which lies in deposits almost at the very surface of the earth, and artificial - it is produced in modern factories from crude oil. Natural asphalt has a high bitumen content - from 60% to 75%, while petroleum asphalt contains only 13-60%.

A very interesting fact is that the largest “asphalt lake” is located on the island of Trinidad; it covers an area of ​​forty hectares and goes more than thirty meters deep. When laying asphalt on the streets of Washington, the capital of the United States, most of it was taken from Trinidad.

Peach Lake Asphalt, Trinidad

Asphalt is used to cover roads, for roofing, for the manufacture of various varnishes, adhesives and putties, and is also used as an electrical and waterproofing material.

Background to the heyday

In the nineteenth century, city streets were initially paved with stones. In countries such as the USA, Switzerland, and France, from the mid-nineteenth century, bitumen-mineral mixtures began to be used for road surfaces. The first cast asphalt based on petroleum bitumen appeared in the USA in 1876. Asphalt concrete became the “pioneer” of paving in Paris in the 1930s during the laying and improvement of the Royal Bridge, and a little later for the bridge called Moran, which was thrown across the Rhone River in Lyon.

Road communications developed very rapidly and required new technologies and types that were built as quickly and easily as road surfaces.

The first road surface was created using an industrial method in the USA in 1892; it was 3 meters wide and made of concrete. And twelve years later, road structures were already produced using a tarmacrator, through which hot bitumen flowed freely.

The pioneer of mass production of asphalt in Russia was engineer I.F. Buttats. The first Russian plant to produce this road material was Syzran (back in 1873).

The advantages of asphalt in the modern world

As it turns out, asphalt is suitable in an ideal way material for road surfacing, because it has many advantages. Over time, it became smoother, which reduced wheel noise. Unlike cement concrete, which was used previously, asphalt concrete quickly dried, hardened, gained strength and “allowed” traffic to open almost immediately. Cement concrete needed twenty-eight days for this.

IN modern world Asphalt is widely used and is the most popular covering material for various areas. One of the many advantages of this bituminous substance is its ductility and ability to bend rather than break. This is very important when creating runways, since sometimes the weight of an aircraft can exceed 140 tons. This quality is also significant in the creation of highways along which huge trucks drive, weighing more than forty-five tons.

Asphalt pavement is very practical, it can be easily repaired, perfectly adheres to any road markings, is easy to clean and has the necessary rigidity for wheel adhesion to the road.

Modern technologies do not stand still and continue to develop. This applies to both asphalt material and methods of covering it. The ability to withstand extreme heat and extreme cold without fear of temperature changes has long been added to the list of advantages.

We have all heard the expression “Asphalt jungle”, which is associated with huge megacities where all the roads are paved. Few people can imagine life without asphalt - without roads, without playgrounds, without these rivers of black building material that encircle our entire Earth. Few people think about how asphalt was created, how we got this unique invention of man, without which modern life would be impossible!?

The history of the creation of asphalt.

Asphalt, in its classical formula, is a combination of bitumen and mineral substance(gravel or sand). More than 60% of the world's roads are covered with this asphalt. It first appeared in 1830, when in Europe they began to combine bitumen with minerals and discovered that this mixture was very practical for creating durable ground layers. This is how the first asphalt roads began to appear. land in the world. Initially, their purpose was exclusively production - for faster movement Vehicle, cars were still far away then. Its development asphalt t received in parallel with the development of mechanical engineering, when strong road surfaces connecting big cities together.

Later, it was necessary to make asphalt roads more durable - this is how asphalt concrete appeared, which is used in road construction and in our days. Asphalt concrete is a mixture based on the combination of a solid base, often made of crushed stone, and an asphalt mixture, which is improved every year, since road surfaces are not able to withstand modern loads on them.

So, in the modern world they use several types of asphalt:

• Peach Lake Asphalt- asphalt mined in the modest republic of Trinidad and Tobago. Every year, asphalt is exported to dozens of leading countries in the world, as it is famous for its exceptional strength and reliability;
• Classic asphalt– asphalt, the most common natural asphalt used in construction worldwide. Classic asphalt is mined in Canada, Russia, Venezuela and France;
• Artificial asphalt– produced by factories using a combination of bitumen, crushed stone and minerals. This type Asphalt covers most of the road surfaces on our planet.

These three types of asphalt are the most common in the world. There are many additives to asphalt that make it more durable and wear-resistant, but the basic formula of the composition is asphalt, has been preserved for centuries.

Is it possible to lay asphalt in puddles, mud or just on snow? Infographics

Many have repeatedly observed the process of laying asphalt in winter or late autumn. But hardly anyone tried to delve into technical features this process. It turns out that it is possible to repair roads at this time of year, but under certain circumstances.

According to the current Soviet SNIPs, asphalt cannot be laid at temperatures below +15, but now new materials and technologies have appeared that allow work to be carried out even at sub-zero temperatures. But not lower than -10 ºС.

What needs to be done to lay asphalt in winter?

To carry out road repairs in winter, it is necessary to prepare the area: remove snow, ice and treat the area with special reagents.

Rain and snow reduce the temperature of the mixture, so it is not recommended to lay thick layers of asphalt in wet weather. Stow road surface in light precipitation it is possible only along the entire width of the road, and not in parts in different days. In heavy rain and snowstorms, laying the canvas is impossible.

How is asphalt laid?

Laying asphalt consists of the following stages: the cleared area for the new route is covered with crushed stone. Then the emulsion is poured, which should ensure the fixation of the asphalt. Another layer of bitumen and dry crushed stone is applied on top, and the surface is leveled with a roller.

Why do potholes and cracks appear on the road?

When laying asphalt, road services often save money. First of all, on the emulsion, the task of which is to hold crushed stone. As a result, asphalt is placed on a dry surface, so it quickly begins to move apart, forming cracks.

The second thing they are trying to save on is crushed stone. Instead, crushed bricks, which are incomparable to gravel in strength, can be placed under the asphalt. As a result, the asphalt collapses, forming holes. According to the standards, for a “light” road one layer of the middle fraction (20-40 mm) is sufficient. If this is a highway, then it is recommended to lay crushed stone in several layers: the first layer is from a coarse fraction (40-70 mm), followed by a medium one, and the last one from a fine fraction (5-20 mm). The main thing is to roll each layer with a roller.

Road builders also save on the surface itself—asphalt. It, like bitumen emulsion, is made from oil. But not every variety of this raw material is suitable for high-quality styling expensive As a rule, builders do not check the quality of oil, hence the fragility of the coating. The thickness of the asphalt depends on the intended use of the road. Minimum thickness is 4-5 cm (for courtyard areas, etc.). At high intensity traffic The asphalt is again laid in layers using different grain sizes. Coarse-grained asphalt concrete is placed as the first layer, followed by fine-grained asphalt concrete on top. For greater reliability, put a third surface layer. Before applying each next layer, the previous one is watered with bitumen.

Well, the main reason bad roads- negligence. Cracks often appear due to water that penetrates under the pavement and freezes during cold weather, thereby expanding the holes in the road surface. Builders may neglect technical requirements and put asphalt on the snow. These actions conceal not only negligence, but also the possibility of receiving another order. If you put it in a puddle, you’ll have to redo everything in a couple of months, and then a new order is ready, and you can blame everything on the harsh climate.

When should cold and hot paving be used?

There is a cold and hot way laying asphalt.

Cold laying is most often used when repairing roads. The main thing in this process is to compact the coating well. The advantage of using cold asphalt is its all-season use.

Road repair work can continue even in winter.

There are several types of cold asphalt:

Summer cold asphalt. Temperature environment when laying from +15 to +30 °C.

Off-season cold asphalt. Ambient temperature during installation is from -5 to +15 °C.

But this method is not suitable when building a new road or major renovation old. In this case, resort to hot styling. Asphalt must be laid while hot. However, in the fall and in early spring achieve quality repairs roads using hot laying are difficult.

Instead, they use cast asphalt technology. Mold asphalt is a mixture of sand, gravel and ground limestone with bitumen. Cast asphalt does not need to be rolled with rollers; its consistency is such that it lays down in a dense cast layer without the need for additional compaction. Cast asphalt is water-resistant, so it can be laid even when it rains. The temperature of cast asphalt during installation can vary between 200-250 degrees. The technology allows laying asphalt at -10 °C. The maximum thickness of cast asphalt should not exceed 25-30 mm. Cast asphalt, like other types of asphalt, can be used not only in road construction, but also in such types of work as roofing, bridge coverings, and interior decoration.

The roads are meant to last for three years.

Since 2011, new rules have come into force, according to which road repairs should be carried out not once every seven years, as it was before, but once every three years. According to officials, due to climatic conditions A road in Russia lasts no more than three years.

In the same year, the capital's utility workers began keeping track of the history of roads. The documents indicate when a particular kilometer of the highway was repaired. If a defect is discovered, the contractors who carried out the work must correct the errors at their own expense.

Comparative cost of roads in Russia and abroad

Some road work in Russia is several times more expensive than the cost of roads abroad. The first on this list is land that needs to be purchased from the owners. In Russia it is usually included in the cost of the project, but in Europe it is not. At the same time, the cost of land acquisition in Russia amounts to 6-7% of the project cost, in the Moscow region - 30%, and in Moscow - up to 70%. Many people buy land adjacent to the future route in advance and then sell it to the state at exorbitant prices.

The next most expensive is the cost of design. In Russia there are virtually no standard projects expensive, so every new road has to be redesigned. Then the project is sent for state examination, which is almost impossible to pass the first time. A repeated examination costs up to 70% of the initial one - and this does not take into account the cost of finalizing the project.

And third is the delivery of materials. High-quality sand and crushed stone often have to be transported tens or even hundreds of kilometers away. A simple example: during the construction of some tunnels in the Olympic Sochi, finishing was used that was produced in Krasnoyarsk. With delivery five thousand kilometers away.

As a result, it is not surprising that the construction of the Adler - Krasnaya Polyana road cost 285 billion rubles - 1.9 times more expensive than foreign analogues. In Europe, the cost of laying one kilometer of tunnel in a mountain range is about $70 million.

The only reason why a road in Russia may be cheaper than a European one is that the road pavement is thinner and designed for a shorter service life. In Germany, the thickness of the top layer of asphalt should be 22 cm. In Russia - 8 cm. All this affects the service life. In addition, while the quality of the asphalt used can be checked, the amount of sand and crushed stone cannot be checked. That's why road workers use this: if you want, put it down less material, if you want, indicate in the documents the delivery range of the required sand of 200 km, and bring regular sand from the nearest quarry.

ABOUT good roads Russians can only dream or build them under contracts life cycle so that the contractor himself maintains the constructed road and pays fines in case of poor installation.