What is the asphalt of our traditional sidewalks made of? History of Moscow pavements: from wood to tiles When asphalt was invented.

Asphalt is a natural or artificial multicomponent material based on surface (formed when it comes to the surface of the earth) or oil (obtained as a result of oil refining and subsequent processing of the tar remaining in the sediment) bitumen containing mineral fillers - gravel, crushed stone different breeds, sand.

In fact, the application of the term "asphalt" to road asphalt mixtures is incorrect. The content of asphalt as a mixture of bitumen in the total mass is several times less and depends on the grade of the material.

The beginning of the use of asphalt for road construction

The first mention of the use of natural asphalt for road construction refers toXVIcentury and South America. The production of artificial poured asphalt mixes appeared in the USA only at the end ofXIXcentury, bitumen-mineral compositions came to the streets of Europe a little earlier - in 1830-40. paved sidewalks and roadways in the cities of France, Austria, Great Britain and Russia began to be replaced with asphalt pavements.

The first trial and larger-scale experience of asphalting was carried out in St. Petersburg, but only by 1980. the new road material spread to other major cities. At the same time, its own plant was not built in Russia immediately - for three decades, the then progressive product was purchased abroad.

America again proved to be a pioneer in mechanized laying. It was here that an asphalt distributor was first used to build the road, from which hot bitumen poured.

The composition of natural and artificial asphalt

Natural asphalt is mined from rare deposits - Peach Lake in Trinidad, Dead Sea in Israel, Alberta in Canada, Orinoco Belt in Venezuela, US states, Iran, Cuba. The composition includes a mixture of bitumen with a content of up to 70%, inorganic inclusions and organic compounds.

Artificial asphalt mixes consist of two main components. Viscous, low-viscosity or liquid petroleum, modified bitumen and PBB (polymer-bitumen binders) act as a binder component. Crushed stone / gravel of different fractions from 5-10 mm to 20-40 mm, sand and mineral powder are used as fillers to improve strength, viscosity and fill voids.

Asphalt concrete is a monolithic road surface obtained by laying and compacting an asphalt concrete mixture.

Asphalt production technology

The main steps in the production of any asphalt mix are the preparation of components, mixing and storage in a bunker. Production is carried out at stationary and mobile (located near the road construction site) plants.

General technological steps:

• Preparation of the mixture components. Mineral fillers are crushed and separated into fractions using a screen, dried, heated, dosed and fed into the mixer.
• bitumen preparation. The heated bitumen is fed to the bitumen melting plant, kept under constant stirring, adding surfactants and raising the temperature until the moisture evaporates, is sent to the working boilers and to the batching of the mixer.
• Mixing components. Prepared crushed stone / gravel, sand are fed into a forced-action asphalt mixer for “dry” mixing with the addition of mineral powder and the subsequent addition of heated bitumen and mixing until a homogeneous mixture.
• Overload ready mix. Hot mix asphalt is sent to a storage bin or loaded into dump trucks for transportation to construction site. The cold mixture is cooled and transported to a warehouse for storage.

Heating of crushed stone and bitumen in the production of hot mixes is carried out to a temperature of 165 ... 175 0 С and 140…155 0 C, in the manufacture of cold mixes - up to 65 ... 75 0 С and 110…120 0 C respectively.

The classification of asphalt mixes is carried out according to residual porosity, type of mineral materials, their fraction and percentage, bituminous binder and laying temperature.

Separate types of asphalt concrete mixtures

In addition to traditional and widely used asphalt concrete mixtures, there are more progressive road materials that differ from the first in composition and laying conditions.

These include:

• Crushed stone-mastic mixtures of ShchMA with stabilizing additives.
• Cast asphalt mixtures with increased content of bitumen and mineral powder.
• Polymer-asphalt-concrete mixtures with the addition of polymers (elastomers).
• Colored hot and cold mixtures with coloring pigments.
• Glass-asphalt-concrete mixtures with the inclusion of glass cullet.
• Rubber-asphalt-concrete and rubber drainage mixtures with crumb rubber and polymer additives.
• Sulfur asphalt concrete mixtures with the presence of technical sulfur.

Each type of material has a specific area of ​​application, due to the characteristics and performance and properties of the resulting coating.

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

Many have observed the process of laying asphalt in winter or late autumn more than once. But hardly anyone tried to penetrate into technical features this process. It turns out that it is possible to repair roads at this time of the 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 you to perform work even at sub-zero temperatures. But not below -10 ºС.

What needs to be done to lay asphalt in winter?

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

Rain and snow reduce the temperature of the mix, so thick asphalt layers are not recommended in wet weather. In case of light precipitation, it is possible to lay the pavement only along the entire width of the road, and not in parts on different days. In a downpour and a snowstorm, laying the canvas is impossible.

How is asphalt laid?

Asphalt laying consists of the following steps: the cleared area for the new route is covered with rubble. Then pour the emulsion, which should ensure the fixation of the asphalt. Another layer of bitumen and dry gravel is applied on top, the surface is leveled with a roller.

Why do holes and cracks appear on the road?

When laying asphalt, road services often save money. First of all, on an emulsion, the task of which is to hold the rubble. As a result, the asphalt is laid on a dry surface, so it quickly begins to disperse, forming cracks.

The second thing they are trying to save on is crushed stone. Instead, they can put a chipped brick under the asphalt, which is incomparable in strength with gravel. As a result, the asphalt fails, forming holes. According to the regulations, for an “easy” road, one layer of medium fraction (20-40 mm) is enough. If this is a highway, then it is recommended to lay crushed stone in several layers: the first layer is from a large fraction (40-70 mm), followed by a medium one, the last one is from a fine one (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 grade of this raw material is suitable for high-quality road laying. 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. The minimum thickness is 4-5 cm (for yard areas, etc.). At high intensity traffic asphalt is again laid in layers, using different grain sizes. Coarse-grained asphalt concrete is placed in the first layer, fine-grained concrete is placed on top. For greater reliability, a third surface layer is placed. Before applying each next layer, the previous one is poured with bitumen.

Well, the main reason for bad roads is negligence. Cracks often appear due to water that penetrates under the pavement and freezes during cold weather, thereby expanding holes in the roadway. Builders may neglect technical requirements and put the asphalt on the snow. In these actions lies not only negligence, but also the possibility of obtaining another order. You put it in a puddle - in a couple of months everything will be redone, so a new order is ready, and everything can be attributed to the harsh climate.

When should cold and hot asphalt be used?

There is a cold and hot way asphalt laying.

Cold laying is most often used in road repairs. The main thing in this process is to compact the coating well. The advantage of using cold asphalt is its all-weather application.

Work on the repair of the road can not be stopped even in winter.

There are several types of cold asphalt:

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

Interseasonal cold asphalt. Ambient temperature during laying from -5 to +15 °C.

But this method is not suitable for the construction of a new road or overhaul old. In this case, resort to hot styling. Asphalt must be installed hot. However, in autumn and in early spring achieve quality repair roads using hot laying is difficult.

Instead, poured asphalt technology is used. Molded asphalt is a mixture of sand, gravel and crushed limestone with bitumen. Cast asphalt does not have to be rolled with rollers, its consistency is such that it lays down in a dense cast layer without the need for additional compaction. Molded asphalt is water resistant, so it can be laid even when it rains. The temperature of the poured asphalt during laying can vary between 200-250 degrees. The technology allows laying asphalt at -10 °C. The maximum thickness of the poured 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 covering, and interior decoration.

Roads are measured to serve 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 the road in Russia serves no more than three years.

In the same year, the capital's communal services began to keep the history of roads. The documents indicate when a particular kilometer of the highway was repaired. If a marriage is found, 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 works in Russia cost many times more than the cost of roads abroad. The first in this list is the land that needs to be redeemed from the owners. In Russia, it is usually included in the cost of the project, but not in Europe. At the same time, the cost of land acquisition in Russia is 6-7% of the project cost, in the Moscow region - 30%, and in Moscow - up to 70%. Many people buy up the land adjacent to the future highway 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 have to be redesigned. Then the project is sent for state expertise, which is almost impossible to pass the first time. The re-examination costs up to 70% of the initial one - and this is without taking into account the cost of finalizing the project.

And the third is the delivery of materials. High-quality sand and gravel often have to be transported for tens or even hundreds of kilometers. A simple example: during the construction of some tunnels in the Olympic Sochi, finishes made in Krasnoyarsk were used. With delivery for five thousand kilometers.

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 a tunnel in a mountain range is about $70 million.

The only reason why a road in Russia can be cheaper than a European one is thinner pavement, 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, if the quality of the asphalt used can be checked, then the amount of sand and gravel cannot. Therefore, the road builders use this: if you want, put less material, if you want, indicate in the documents the delivery distance of the necessary sand is 200 km, and bring the usual one from the nearest quarry.

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

We have all heard the expression "Asphalt jungle", which is associated with huge metropolitan areas, where all small paths are paved. Few people can imagine life without asphalt - without roads, without playgrounds, without these rivers of black building material that encircled 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 roads in the world are covered with such asphalt. It appeared for the first time in 1830, when in Europe they began to combine bitumen with minerals and discovered that this mixture is very practical for creating durable ground layers. This is how the first paved roads began to appear. land in the world. Initially, their purpose was exclusively production - for faster movement. Vehicle, the cars were still far away. Its development asphalt t received in parallel with the development of mechanical engineering, when strong roadbeds were required connecting large cities with each other.

Later, it was necessary to make asphalt roads more durable - this is how asphalt concrete appeared, which is used in road construction today. Asphalt concrete is a mixture based on the connection solid foundation, often from crushed stone, and an asphalt mixture, which is being improved every year, since the roadbeds are not able to withstand modern loads on them.

Yes, in modern world apply several types of asphalt:

• Asphalt Peach Lake- asphalt mined in the modest republic of Trinidad and Tobago. Every year, asphalt is exported to dozens of leading countries of the world, as it is famous for its exceptional strength and reliability;
• Classic asphalt- asphalt, the most common natural asphalt, which is used in world construction. Classical 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 of our planet.

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

Asphalt has deep historical roots; it was already known to the ancient Egyptians and Phoenicians. But, unlike our time, asphalt was intended for completely different purposes than the coating of ancient roads. If you figure out what asphalt of natural origin consists of, then mountain natural asphalt contains up to 75% bitumen. The very name of asphalts is due to the Greek word "ἄσφαλτος", which can be translated as "mountain resin".

The Egyptians used asphalt to make embalming compositions to preserve the mummies of the pharaohs. Avicenna recommended asphalt for the treatment of diseases by analogy with the mummy. Practical Phoenicians and Indians impregnated their sea ships and canoes with asphalt compositions. Few people know that until the 20th century, the Dead Sea was called the Asphalt Sea, because the blocks of this natural material float to the surface.

The history of the use of bituminous compounds

By origin, asphalt compositions or mixtures are divided as follows:

1. Natural asphalts, which are formed from heavy fractions of oil and their residues after the evaporation of lighter constituents;
2. Artificial asphalts (so-called asphalt mixes) are building materials made from mixtures of bitumen and other substances.

Definitely, the composition of asphalt should include bitumen as a binder and mineral aggregates. But if bitumen is included in natural asphalts in an amount of up to 75%, then artificial asphalt concrete mixtures contain bitumen in the range of 4-10%. Bitumen owes its uniqueness to asphalt mixtures.

Interestingly, before pottery, Neolithic people used bituminous utensils for cooking. The astringent properties of bitumen were used by ancient hunters and fishermen when attaching spearheads and for waterproofing their boats. As already mentioned, bitumen in the composition of asphalts was used by ancient healers.

The first half of the 19th century is significant for the appearance of bitumen-mineral mixtures as a coating for cobblestone bridges. major cities France, Holland, Switzerland, and a little later - in the USA. According to the chronicles of those years, the first asphalt pavement was laid in the 30s of the 19th century on the sidewalks in Paris. Around the same years, the pavement of the Moran bridge over the Rhone in Lyon was paved.

Asphalt works in Russia are more accurately dated:

• 1839 - asphalting in St. Petersburg, the length of the pavement was 45.5 linear meters;
• Then - a part of the Tuchkov bridge with a length of 8.5 meters;
• Moscow is slightly behind northern capital, the coating was laid in the 70s on Tverskaya Street, but it was already a new, asphalt concrete coating.

The bitumen used in asphalt mixes for paving gave elasticity to the roadway, and its ability to spread allowed the finished mix to be evenly distributed, covering the existing road roughness. An even layer of the road surface immediately attracted attention, sharply reducing the noise effects from passing vehicles. Recall that in the middle of the 19th century there was no trace of motor transport, and the wheels of horse-drawn vehicles were not equipped with inflatable tires.

In addition to being used as a road material, bitumen is used in a number of other areas of production:

• Waterproofing device in buildings, structures, road surfaces;
• With the help of bitumen, waterproofing of pipeline systems is carried out;
• Bitumen is part of roofing materials;
• Bitumen is necessary in the manufacture of filling mastics for batteries;
• cable and paint industry will not do without bitumen.

Varieties of asphalt concrete mixtures

The basis for the classification of the entire set of asphalt concretes is not the basic list of components included in the texture of a particular mixture, but the proportion of components, that is, the asphalt composition in percent plus the values ​​of the individual defining characteristics of the included components. According to the percentage of the main components, asphalts are divided into three main types:

• Mark 1, the scope of which is limited to the construction of roads and urban improvement. These materials are not recommended for the role of the top covering layer of road surfaces. They are used as a leveling substrate for laying materials that are superior in density;
• Grade 2, which is the proverbial "average" asphalt concrete for a wide range of applications, from new road construction to current repairs and landscaping;
• Mark 3, which does not contain crushed stone. It is replaced by mineral powders and high quality sand.

It is important! The ratio of the weight fractions of mineral components and bitumen determines the strength of the asphalt concrete canvas. Sand mixtures are suitable only for landscaping the park, while high content bitumen is needed to cover the autobahns.

In which city did the first paved road appear?

Asphalt was the first oil product that man met. Natural asphalt - one of the types of natural bitumen - is a viscous resinous substance formed from heavy fractions of oil as a result of long-term weathering. It occurs in the form of reservoir vein deposits, as well as lakes in places where oil naturally comes out to the surface of the earth. It is a hard, fusible black mass containing 25–40% oils and 60–75% resinous asphaltene substances. The word "asphalt" (from the Greek "asfales" - strong, strong, reliable) has been known since the time of Herodotus, who described Mesopotamian and Persian asphalt deposits in his "History".
People found the use of natural asphalt at the dawn of civilization - in ancient Egypt 5000 years ago, the floor and walls in barns for storing grain were covered with asphalt. In Babylon, it was used as a binder in masonry. stone walls- the Bible says that when building Tower of Babel"earthen tar" was used, as asphalt was called in ancient times. The same Babylonians, when constructing the famous Hanging Gardens of Babylon, used a layer of asphalt mixed with reeds for waterproofing. For 400-500 years BC in Media, the walls of fortresses, as the ancient Greek historian Xenophon testifies, were built of bricks held together with natural bitumen. In the same way, on bitumen, the first sections of the Great Wall of China were erected.
As for the road use of asphalt, which is more familiar to us, natural asphalt was used in the construction of roads in America, more than half a thousand years before such use of asphalt was thought of in Europe and the USA. When in 1532 a detachment of Spanish conquistadors led by Francisco Pizarro entered the territory of the Inca Empire, they were amazed, among other things, by the magnificent roads covered with asphalt.
But the great civilizations of the past perished, and the asphalt construction material was forgotten for centuries and millennia. Right up to the start 19th century the streets of all cities in the world, at best, were paved with stones, and only then in large cities began new era the era of asphalt. In 1832 - 1835. in Paris, the first work was done on paving city streets and sidewalks with asphalt. Further, in 1835-1840, it was the turn of London, Vienna, Lyon, Philadelphia and some other cities.
AT Russian Empire The first experience of using asphalt was made in 1839, when in St. Petersburg almost 100 meters of a one and a half meter wide pavement near the Tuchkov Bridge were covered with it. On a somewhat larger scale, asphalt was used in 1865 when the terraces were paved. Winter Palace. But already next year, asphalt began to be widely used on ordinary St. Petersburg streets, squares and courtyards, and by 1880 many streets in Kronstadt, Moscow, Riga, Kharkov, Kyiv and Odessa were covered with it. True, the first asphalt plant was built in Russia only in 1873, a few miles from Syzran, and before that, asphalt was purchased abroad.
Since the middle of the 19th century, in France, the USA, Switzerland and other countries, road surfaces have been made from bitumen-mineral mixtures. In the United States, cast asphalt prepared using petroleum bitumen was first used in 1876. Then, in 1892, the first road structure 3 meters wide was built using the industrial method, and 12 years later, 29 km of the road was built using a free-flowing asphalt distributor with hot bitumen.
The booming road network required new types of pavement, and the asphalt turned out to be the most suitable material. It can be laid almost perfectly evenly, it is a very quiet coating, but at the same time it has the necessary roughness. modern roads covered with asphalt, made on the basis of petroleum bitumen, obtained as a result of air oxidation of heavy residues of oil distillation at a temperature of 239-340 °C. This process was developed in 1896 and put into production in 1914.