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

Many people have repeatedly observed the process of laying asphalt in winter or late autumn. But hardly anyone tried to understand the technical features of 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.

Is it possible to lay asphalt in rain and snow?

To understand whether it is possible to lay asphalt in rain and snow, you need to know about the methods of laying it. And there are only three of them:

• hot;
• cold;
• cast.

The hot method is relevant for the construction of new roads, repair work involving the removal of old asphalt or small sections of roads in warm weather. The method involves the use of a bitumen mixture, which must be rolled until completely cooled. The peculiarity of installation is that certain conditions must be met: the air temperature outside must be above + 5 °C and there is no precipitation.

The cold method is chosen for the so-called pothole repair. In this case, ready-made asphalt mixture is poured into the pit; no special equipment is required. Repair work can also be carried out in frosty temperatures of -20 °C. Cold asphalt can be laid in the rain, but the pit must be well dried. For this purpose, infrared heaters, aircraft engines and special reagents are used.

The cast method of laying asphalt can be used in rain (not downpour), snow, frost down to -10 °C. The finished mixture is delivered to the repair site in thermos tanks, the temperature of which reaches about 200 °C. Because of this, asphalt has a structure similar to liquid glue. When such asphalt comes into contact with a wet surface, all moisture instantly evaporates. The method is quite expensive, so it is used only in emergency situations.

Important! Asphalt can be laid in rain and snow, but certain conditions must be met.

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, the 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.

Features of proper asphalt laying

The process for properly laying a road surface is as follows:

• preparation of the work site (clearing);
• the prepared area is covered with crushed stone;
• on top of the crushed stone, for better adhesion of the base and asphalt, an emulsion mixture is poured;
• a layer of bitumen and dry crushed stone are applied on top of the emulsion;
• the resulting layers are leveled with a roller.

Read on topic: Machines for pothole repair

Requirements and recommendations:

1. Bitumen emulsion should be applied to the surface immediately before laying the sheet.
2. The hot method can only be used at positive air temperatures (not lower than +5 °C).
3. It is important to maintain a certain temperature of the mixture (not lower than + 100 °C).
4. Based on the purpose of the coating, its thickness will be determined. After applying the required length of asphalt, it is leveled and compacted.
5. It is necessary to compact immediately after backfilling, for which special equipment is intended.
6. Allow at least a day for the applied layer to harden. For cold asphalt, a few hours are enough.

Are there exceptions to the rules?

Rosavtodor has made its recommendations on this matter, so first let’s turn to them. These recommendations, which are of an official nature, indicate that laying asphalt concrete can also be done during precipitation, but only if it is of low intensity. If the precipitation level reaches 5 mm, then it is considered heavy.

However, it is worth noting that this recommendation is not suitable for all types of asphalt concrete. There are 3 main types of asphalt:

• hot;
• cold;
• cast.

Hot asphalt, which has fairly high strength characteristics, is usually used for road construction and major repairs. Such asphalt cannot be laid if the thermometer drops below +5°C, or in the presence of precipitation.

The main reasons for poor road quality

Important! Failure to comply with the regulatory requirements of SNiP and GOST when carrying out repair work leads to poor condition of roads.

There are a number of main reasons for the deteriorated state of roads:

• when carrying out paving work during rain, water gets into the asphalt layers, which leads to the appearance of holes;
• savings on the emulsion mixture;
• the layer is laid of inadequate quality, which is why the crushed stone does not adhere properly to the old asphalt;
• replacing crushed stone with crushed brick, which leads to subsidence and collapse of the road surface;
• the use of asphalt of inappropriate quality and laying of insufficient thickness provoke the appearance of cracks and destruction.

We cannot exclude the fact of human negligence during the work, non-compliance with laying technologies in rain and snow.

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 can be placed under the asphalt, which is incomparable to gravel in strength. As a result, the asphalt collapses, forming holes. According to the standards, for a “light” road one layer of medium 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 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 courtyard areas, etc.). When traffic intensity is high, 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, a third surface layer is applied. Before applying each next layer, the previous one is watered 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 the holes in the road surface. Builders can neglect technical requirements and lay asphalt on 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.

Acceptable violations

Sometimes contractors violate road laying technology. The reason is the constant process of bitumen production and the terms of the contracts. The plant produces, contractors provide transportation equipment.

The quality and properties of the coating become worse over time, so it must be laid on the base as soon as possible. The weather is often unpredictable, and road workers often have to work in the rain.

Compliance with prescribed deadlines is another reason for non-compliance with the technological process. Otherwise, you will have to pay a high fine.

Read on topic: Soil strengthening technology

The process may be disrupted if the work is later redone under normal conditions. The quality of the work performed is checked.

Important! In other cases, organizations are subject to a fine.

Optimal timing for road construction work

Next, we will consider the stages of road work: permissible and recommended conditions.

Optimal timing for road construction work

Stage 1: Preparation (from September to November)

It is in the fall that all preparatory work takes place: a plan is developed and a schedule for road repairs is drawn up; the territory where the work will be carried out is explored; The search for the necessary materials and equipment begins. This is the most convenient period to resolve such issues.

Autumn and winter are the most convenient time to select a contractor and conclude contracts. As a rule, contracts are concluded on an advance payment basis. There is no construction work going on at this time, so you can count on getting a good discount.

If you want to understand all the disadvantages of the site you have chosen for construction, then the off-season is the best time for this. You will see how the soil is affected by rain, snow, cold, how great the risk of flooding is, etc. Thanks to weather changes, you will understand whether it is worth building there and what the risks are.

Stage 2: Coordination (from December to March)

In winter, it is best to submit the necessary papers to government agencies for approval. It is worth considering here that there are many holidays at the end of December and the beginning of January, so the processing time may be delayed. The documents will be accepted, but work on them will most likely begin after the holidays.

According to statistics, decisions are considered in about eight weeks. If the documents are submitted at the end of December, then they should be ready just in time for the end of winter.

If everything goes according to plan, construction could begin in March. And this is the most favorable time for road work.

Modern requirements

SNiP specifies requirements regarding air temperature for work:

• for laying warm asphalt from -10 °C and above;
• in summer and spring, work is carried out at temperatures from +5 °C and above;
• in autumn from +10 and above.

It is recommended to carry out work in dry weather. SNiP contains a clause prohibiting the laying of road surfaces in snow, rain and blizzards. According to the regulations, it is impossible to carry out laying work on a damp, unprepared base.

Work can be carried out in light rain. For this purpose, cold and cast mixtures must be used.

Service life of roads according to regulatory documents

Since 2011, new rules have come into force in the Russian Federation. Restoration work is carried out once every three years, previously the period was seven years. According to the adopted law, a road passport is maintained, which indicates the history of each repaired kilometer. The road construction organization is responsible for the quality of work. All imperfections and defects are eliminated at the expense of the builders.

According to the standards, the destruction of the road surface after pothole repair is only 5 percent. The warranty period is affected by the intensity of traffic flow and operating features.

On highways of categories I and II, the coating changes with a large canvas. As a rule, traffic is blocked in one of the directions. Work must be carried out in accordance with SNiP and GOST documentation.

If it's minus outside the window

At sub-zero temperatures, asphalt is laid using cold mixtures. This is a polymer asphalt obtained thanks to additives, due to which it is plastic and frost-resistant. Adhering to technology, the use of the composition requires the addition of bitumen thickeners. There are two types of cold mixtures used: fine-grained and sandy, fractions - 5 mm and 10-15 mm.

In extreme weather conditions it is very important to obtain a durable coating and this technology allows you to achieve this. The cost of the work is high, but cold modified mixtures are increasingly being used due to the ability to carry out work in snow and rain, as well as temperatures of + 60 °C.

Scope of technology application:

• coatings located next to the rails;
• spot repairs of highways and routes;
• access roads, parking lot coverage;
• preventive measures during road repair work;
• formation of a blind area in other cases.

Before work, the surface should be cleaned of excess moisture, snow and debris. Additionally, temperature control mechanisms are required.

Comparative cost of roads in Russia and abroad

Some road works in Russia are several times more expensive than 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.

Article on the topic

Know-how: Kazan scientist figured out how to save roads from destruction

The next most expensive is the cost of design. In Russia there are virtually no standard road designs, so each new road has to be designed anew. 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. Therefore, road workers use this: if you want, put 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.

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

What's special

Modern road surfaces are laid as follows:

1. A place is prepared and thoroughly cleared.
2. Crushed stone is poured in a layer of at least 5 cm.
3. A special emulsion is poured.
4. A layer of bitumen is applied and dry crushed stone is placed on it.
5. The created “pie” is carefully rolled with a roller.

In addition to debris and remnants of the old coating, wet roads are removed from moisture with brushes. After this, they are warmed up with infrared heaters. But they have low productivity. That’s why on our roads you can often find tractors with aircraft engines installed on them. Their hot air flow makes the area suitable for laying the mixture.

Under these conditions, the most durable coating on Russian roads today is obtained.

Regulations

Compliance with GOST for carrying out work provides for the following points:

1. The provisions of GOST 9238 are responsible for the asphalt mixture.
2. Maintaining temperature conditions.
3. Use of crushed stone of a certain fraction. Material standards are specified in GOST 8267. Sedimentary rocks are regulated by GOST 8736.
4. Requirements for bitumen are given in article GOST 22245.

SNiP contains information on standards for laying asphalt pavements. The regulatory document specifies the temperature regime for carrying out work.

When should cold and hot paving be used?

There is a cold and hot method of 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.

Article on the topic “Let’s rid the city of potholes!” Where to report broken roads

Road repair work can continue even in winter.

There are several types of cold asphalt:

– Cold summer asphalt. Ambient temperature during installation is 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 for the construction of a new road or major repairs of an old one. In this case, resort to hot styling. Asphalt must be laid while hot. However, in the fall and early spring it is difficult to achieve high-quality road repairs using hot laying.

Instead, cast asphalt technology is used. 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 poured 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.