Road repairs in winter. Repair technology with cutting maps when using cast asphalt concrete mixtures

Asphalt is a fairly reliable material used to cover roads. For high loads, brands with the best characteristics are intended, for example, M1200.

Less dense material (M1000) cannot withstand the load from the weight of numerous cars, for this reason it is usually laid only when constructing sidewalks and paths.

First of all, it is necessary to plan the area where the asphalt will be laid. Required work are planned taking into account the purpose of the coating. For a “light” highway, with low traffic flow, only 1 layer of crushed stone will be required, but to build a serious highway, a minimum of 3 layers is required.

Crushed stone fractions are arranged from maximum to smallest, after which they are carefully rolled with a roller. This is required to create a special cushion (base), on which asphalt is poured. All asphalt laying work is carried out taking into account the requirements of SNiP and GOST.

There are 2 main technologies for pouring asphalt:

1. Cold way. They are most often used for repairing asphalt pavements, since such material sets in short term, and the repaired asphalt can be used without restrictions;
2. Hot method. Used to create new asphalt pavement. For this method, the heated bitumen-based mixture must be poured and rolled until it cools down.

The cost of repairing bitumen should not be less than 0.5 liters, and when creating a new route, the material consumption must be calculated separately. In this case, it is necessary to take into account not only the dimensions of the asphalt surface, but also its structure and possible additional factors.

During work, it is imperative to use a special thermometer, which makes it possible to measure the temperature of the bitumen mixture. Constantly checking this indicator is of great importance, because after the material has cooled, it can no longer be used for asphalt pavement construction.

Application of impregnation

Currently, 3 types of impregnation are used for this purpose:

1. Based on acrylic polymer. Most expensive coverage, it is used only in small spaces, for example, on a tennis court. They create the highest quality protection, and they also come in several colors;
2. Coal tar. Coating that is resistant to petroleum products. With the help of special components, in addition to a long service life, a visually attractive shade is achieved;
3. Asphalt emulsion. Available and popular material, but it is not able to provide necessary protection coating, which forces the asphalt surface to be repaired more often.

If cracks appear on the asphalt, a non-bitumen mixture can be used for repair. It’s better to use a sealant sprinkled with cement on top.

To ensure maximum pavement strength and prevent the formation of cracks, special meshes are placed under the asphalt.

They create high-quality adhesion of the new coating, increase the performance characteristics of asphalt and increase the time of its use.

Compaction is an essential consideration when laying asphalt pavement. It is produced using special machines - a roller, an asphalt paver, or a vibrating plate is used; this is not very mobile equipment, but it has a number of advantages over other rolling methods. For example, an asphalt paver can perform at least 2 types of work, and a vibrating plate is the most maneuverable among them.

Laying asphalt according to GOST

Mixing of components is carried out in accordance with GOST 9128, the mixture is divided into 2 types, according to installation conditions:

• for use at temperatures exceeding +5 degrees;
• for use at temperatures in the range -25 - + 5 degrees.

Crushed stone, which is part of the mixture for laying asphalt, must be selected in accordance with the requests specified in GOST 8267, screenings are standardized according to GOST 8736. Bitumen are used as the binder component of the mixture - BND 90\130 and BND 60\90, corresponding to GOST 22245.

The influence of material on the quality of asphalt pavement

In order not to buy low-quality asphalt concrete, the seller must be required to provide a certificate of conformity for the product. There are a number of laboratories that perform asphalt testing and sampling. Asphalt analysis is carried out by examining a selected core (asphalt core).

Improvement of asphalt pavements

Despite their practicality, asphalt sheets can be modernized. One of effective methods is the use of mastics specifically designed to improve asphalt. They contain bitumen and special emulsions for it, which contain rubber and polymer additives.

In most cases, bitumen mastics are used heated, and emulsions are used without heating. Mastics close pores and cracks on the surface of the asphalt; this does not allow moisture to penetrate under the asphalt and destroy its structure - when freezing, moisture breaks the coating and creates water hammer when vehicles pass.

Do-it-yourself asphalt laying

In your home or country house, asphalt pavements are suitable for constructing sidewalks and creating paths; they are used to make blind areas. In addition, this material can be used to create roofing coverings.

The paths are laid in stages:

1. Pre-clean up trash and remove soil to a depth of 30 cm;
2. After this, curbs are installed, serving not only as decoration, but also as walls for bitumen;
3. Next, arrange a pillow. A layer of crushed stone is poured to a depth of 15 cm, then it is compacted, a layer of fine crushed stone is filled in and rolled again. The sand is poured last, in a layer of 5 cm. The prepared pillow must be thoroughly shed with water and then rolled with a hand roller;
4. Hot asphalt must be spread evenly over the area of ​​the path. After that, the unevenness is leveled with a motor mop, while simultaneously filling the resulting depressions with new portions of asphalt. Since the material cools quickly, it is better to do the work with 1-2 assistants;
5. After the asphalt has been laid and leveled, you need to compact it with a hand roller. Before work, the roller needs to be lubricated with diesel fuel; this will help create an even and smooth coating (the asphalt will stick to a dry roller). It is advisable to coat all tools used during work with diesel fuel.

When laying asphalt, it is important to monitor its temperature. It must be maintained at a level of at least 120 degrees; a coating laid from cold material will completely deteriorate in a short time.

In addition, when laying, it is important to perform only straight movements with the tools; in no case should they be returned to you along the surface of the coating.

After completing all the work, you can impregnate the coating by replacing the impregnation with a special paint intended for asphalt. With its help you can get the shade you need.

Asphalt repair

The asphalt structure is destroyed not only by physical activity, but also under the influence of the sun's rays, which over time destroys bitumen and makes the surface fragile.

There are 3 main asphalt restoration technologies:

1. The first method: sealing cracks in the coating using tar. The surface intended for repair is cleaned in advance. Taking into account the size of the crack, 2-3 cm is covered with sand and then filled with tar, or if the width of the defect is small, tar is used immediately. After 10-15 minutes have passed, the sealed asphalt must be leveled with a spatula. Do the same with other cracks on the surface.
2. Second method: you can buy rolls of ready-made asphalt. This is an inexpensive and practical product and what is important is that it is convenient to use for minor repairs. The rolls are rolled out, and after removing the protective layer, they are placed on the surface with an adhesive surface. Press the roll tightly for a few seconds and the repair is complete.
3. The third method: will make it possible to eliminate small holes and damage on the asphalt surface. The defect must be cleaned in advance, all debris removed and dust removed. Densely fills all voids with bitumen composition. After 2-3 minutes, the sealed area must be leveled and compacted.

To prevent the destruction of asphalt, it must be renewed every 4-5 years, and any cracks found must be sealed with water and chemically resistant sealant.

If the asphalt begins to crumble, then this coating must be completely changed. It is very easy to apply the sealant, pour it out of the container and brush the surface to be treated well with a stiff brush.

Asphalt repair in winter

To repair asphalt in winter, you will need to first prepare the work site: clear the snow, chip off the ice and treat the defect area with a special compound.

Snow and moisture cool the asphalt; for this reason, it is not worth laying and repairing thick layers of asphalt in wet weather.

In light rainfall, work can only be done on the entire asphalt surface, but work can be done in parts at intervals; during snowstorms and heavy rain, asphalt cannot be poured. Otherwise, after a short time, the bitumen coating will require repairs.

If you eliminate defects in a timely manner, repairing the most worn areas, then it will last much longer. The most important thing during repairs is to carry out milling correctly, this means removing a layer of old coating at the site of the defect using cutters.

A seam cutter is also necessary for removing the used coating layer and for creating seams. Heated asphalt is transported in a kocher; it is designed for transporting hot bitumen mass. To reduce the cost of manual labor, specialized enterprises use real automated complexes.

For example, for the repair of highways, units are used to remove a layer of worn-out pavement, which simultaneously perform cutting of defective material and milling.

Pothole repair

Complete repair of asphalt is not always carried out; the pitting technique is often used, which consists of filling detected defects, cracks and potholes with a bitumen composition. It is used only if the damage to the canvas is no more than 15%.

Before starting repairs, prepare:

Marking. In addition to defective areas, it is also necessary to mark a small part of the whole canvas. If several holes are located in the same radius, then they will need to be painted with the same outline.

Dismantling. After this, the damaged asphalt is removed, for example, using a jackhammer. In this case, it is advisable to use the cold milling method, since with its help you can obtain smooth walls.

Cleaning up. At this stage, crumbs and debris are removed from the coating, and you can begin treating the defective areas with a bitumen compound.

Material rating:

• The asphalts used are the most environmentally friendly, when compared with similar compositions of previous years;
• The cost is quite expensive;
• Can be used to create almost any coating. In addition, it can also be used in the construction of buildings;
• The new asphalt looks quite attractive in appearance, but over time it begins to fade. You can restore its color by painting the surface with a special paint;
• It is impossible to prepare asphalt at home;
• Requires in fast work and use of assistants, because after cooling it is unusable.

When should cold and hot paving be used?

Cold laying of this material is mainly used for repairing coatings. The main thing here is high-quality compaction of the material. A big plus of cold asphalt is that it can be used at any time of the year. The necessary work can be done even in winter.

There are 2 types of cold asphalt:

• Summer. When laying, the desired air temperature is within +15 - +30 degrees;
• Off-season. When laying, the desired air temperature is within -5 - +15 degrees.

But such material is not suitable for major repairs or installation of a new coating. Here it is better to use hot asphalt.

So that in the spring you don’t have to fill the holes with crushed stone or broken brick, as is often customary to do in our country, it is necessary to carry out winter road repairs. Basically, road repairs in winter involve fixing potholes, but restoration of the entire road surface is very rare.

Unfortunately, this is only a temporary remedy that does not allow achieving a “long-lasting” effect, but for most roads this measure is necessary.

Carrying out work of this nature often depends on regional features. Important criteria are duration winter period, degree of soil freezing, absolute value of negative temperatures. The amount of frozen soil in the embankment should not exceed 70%, and its maximum permissible size is more than 20-30 cm. The permissible height of the subgrade during work carried out at a temperature of -20 ° C should not be more than 2.5 m, while at -5°C - height is not limited.

The method of laying hot asphalt concrete with high-quality work allows you to repair holes and potholes for a longer period. To do this, the pothole must be warmed up, cleaned, primed and asphalt laid. An important point, if observed, can achieve the desired effect, is maintaining the required level of asphalt temperature (from +80°C).

A good effect can be achieved by using cold mixture. Instead of viscous bitumen, it uses more elastic analogues, the viscosity of which increases with decreasing temperature. A special additive is introduced into such a mixture, which does not allow the material to quickly harden. Laying the cold mixture can be done at a temperature not lower than + 5°C. When working with this material, the lower permissible threshold for work is -25°C. Such a patch will behave well on roads where there are no traffic jams, at intersections and stops - there will be little benefit from such repairs. Cold mixtures have little resistance to shear. If by the road high degree cross-country ability, then the repaired section can be put into operation immediately - the machines will only compact the asphalt, which will make it more durable.

Another option is cast asphalt. A hot dough-like mixture of high-viscosity bitumen is transported in special boilers or kochers. The installation temperature must be at least +200°C. When cooled, the mixture hardens and compacts itself, even without the use of a roller.

Basic requirements for asphalt pavements in winter:

1. Increase the thickness of the installation by 1 cm, the total thickness is at least 5 cm.
2. Increased bitumen content is required in the mixture used.
3. Carrying out work in the absence or low wind.
4. Intensive supply of material for laying by dump trucks with insulated bodies.

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

Editor's response

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.

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. In light rainfall, pavement can be laid only across the entire width of the road, and not in parts. different days. In heavy rain and snowstorms, laying the canvas is impossible.

How is asphalt laid?

Asphalt laying consists of next 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, they can put it under asphalt crushed brick, which is incomparable in strength to gravel. 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.). 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.

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. 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 in 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 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, 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.

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.

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. 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.

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.

ODM 218.3.060-2015

INDUSTRY ROAD METHODOLOGICAL DOCUMENT

Preface

1 DEVELOPED by the Federal State Budgetary educational institution higher professional education "Moscow Automobile and Highway State Technical University (MADI)"

2 INTRODUCED by the Department of Scientific and Technical Research and Information Support of the Federal Road Agency

5 INTRODUCED FOR THE FIRST TIME

1 area of ​​use

1 area of ​​use

2 Normative references

Temperature cracks occur as a result of cooling and the coating's resistance to thermal shrinkage. Vertically, these cracks develop from top to bottom, from the surface of the coating to the base.

Fatigue cracks that occur when a monolithic layer bends under repeated transport loads develop from bottom to top from the base to the surface of the coating.

Reflected cracks replicate the seams or cracks of cement concrete pavements and are most characteristic of asphalt concrete layers laid on a cement concrete pavement. When the temperature drops, deformation of the cement concrete coating occurs in the form of shortening of the slabs. As a result, the seams or cracks in the cement concrete pavement expand, causing the overlying layers of asphalt concrete to stretch and rupture, forming reflected cracks. To these tensile stresses are added the own tensile stresses from the decrease in the temperature of the asphalt concrete. This is a time-cyclic process that leads to the destruction of the asphalt concrete pavement.

Based on their width, cracks are classified into narrow (up to 5 mm), medium (5-10 mm) and wide (10-30 mm). This classification is typical for temperature and fatigue cracks. For reflected cracks, this approach is incorrect, due to the presence of temperature deformations of the underlying cement concrete pavement, causing movement of the crack edges depending on temperature, the length of the cement concrete slab, the thickness of the asphalt concrete pavement and other factors.

Depending on the width and type of cracks, the technology for their repair and the composition of the equipment used are chosen. The main task when repairing cracks is to prevent water from penetrating through them into the underlying layers of the pavement. Waterproofing cracks is achieved by sealing them with special mastics and repair mixtures.

6.1.3 When choosing mastics, it is necessary to focus on their basic physical and mechanical properties. One of the most important indicators for choosing mastics is adhesive strength, the requirements for which must comply with GOST 32870-2014.

6.1.4 Sealing narrow temperature or fatigue cracks on the surface of asphalt concrete layers laid on a cement concrete pavement does not require complex technological operations. Cracks are cleaned by blowing compressed air, dried, heated and filled with bitumen emulsion or mastic with high penetrating ability.

6.1.5 On thin temperature or fatigue cracks (2-5 mm), heated polymer-bitumen mastic can be applied in the form of a tape that prevents chipping of the coating at the edges of the crack. It is smoothed with a special heating iron (shoe) and sprinkled with fractionated sand. The coating in the crack zone is pre-dried with a heated stream of compressed air.

6.1.6 If a crack has destroyed edges, the repair technology should begin with the operation of cutting it, that is, artificial expansion of the upper part of the crack to form a chamber in which optimal tensile performance of the sealing material is ensured during the period of crack opening.

6.1.7 The width of the chamber must be no less than the destruction zone of the crack edges. To create the best working conditions for the sealant in the chamber, the ratio of the width and depth of the chamber is usually taken as 1:1. In addition, when determining the geometric dimensions of the chamber, it is necessary to take into account the maximum possible crack opening and the relative elongation of the sealing material used. Typically the chamber width is in the range of 12-20 mm.

6.1.8 If a temperature or fatigue crack is not cut to its full depth (the thickness of the cracked coating exceeds 10 cm), then before sealing, a special sealing cord made of an elastic material that is thermally and chemically resistant to the sealant and environment. When using a sealing cord for pressing in, it must be taken into account that its diameter should be 1.2-1.3 times greater than the width of the cut crack chamber.

The depth of the groove after pressing the sealing cord (the upper free part of the chamber) is taken depending on the properties of the sealant.

Instead of a sealing cord, a layer of bituminized sand or a layer of rubber crumb laid on the bottom of the chamber, with a thickness equal to an average of 1/3 of its depth, can also be used, after which the chamber is filled with sealant.

When using bituminized sand, coarse and medium sand is used that meets the requirements of GOST 8736-2014 and GOST 11508-74 *.

Rubber crumbs must have particle sizes in the range of 0.3-0.5 mm and meet the requirements *.
________________
*See section. - Database manufacturer's note.

Depending on the temperature of stickiness and resistance of the sealant to wear under the influence of car wheels, it should be filled with underfilling, flush or with the formation of a patch on the surface of the coating.

6.1.9 In the case where the edges of a temperature or fatigue crack have not been subjected to destruction and it is possible to qualitatively seal the crack without cutting it, this operation can be excluded from the technological process.

6.1.10 The most important condition for ensuring the quality of crack sealing is the presence of good adhesion of the sealant to the walls of the uncut crack or milled chamber. In this regard, much attention is paid to preparatory work on cleaning and drying the crack. To improve adhesion, the walls of the milled chamber are primed with a primer - a low-viscosity film-forming (adhesive) liquid.

6.1.11 The main technological operation when repairing temperature or fatigue cracks is filling them with hot mastic. The mastic is preheated to a temperature of 150-180°C, after which it is fed into a built-in chamber or directly into the crack cavity. In this case, depending on the equipment used, it is possible to seal either the crack itself, or simultaneously with filling with mastic, place a plaster on the surface of the coating in the crack area. This patch, 6-10 cm wide and 1 mm thick, allows you to strengthen the edges of the crack and prevent their destruction.

It is advisable to use sealing with adhesive for cracks with significant destruction of the edges (10-50% of the crack length), because in this case, defects on the coating surface in the crack zone are healed.

The method of remediation of medium and wide temperature or fatigue cracks of asphalt concrete layers laid on cement concrete is divided into five stages:

1. Cutting cracks. In this case, special crack separators are used. To avoid damage to the edges when cutting a crack in an asphalt concrete pavement, it is necessary when choosing cutting tool take into account the composition of asphalt concrete. For crushed stone grain sizes of 20 mm or more, it is recommended to use diamond tool, and when the aggregate size is up to 20 mm, cutters with carbide surfacing can be used.

2. Removal of destroyed asphalt concrete. For this, a high-performance compressor is used. For thorough cleaning both from dust resulting from cutting, and to remove deposits remaining deep in the crack.

3. Drying and warming up. The cut cavity of the crack is dried and heated with a so-called heat lance.

The parameter for stopping heating is the appearance of melted bitumen on the crack walls. Under no circumstances should a crack be overheated; burning out the bitumen will lead to a sharp decrease in adhesion and further destruction of the coating around the crack.

In this regard, heating the crack with open-flame burners is unacceptable.

4. Filling the crack cavity with sealant. Immediately fed into the cleaned, dried and heated cavity of the cut crack bitumen mastic from a melting and casting machine.

Modern pourers, in general, are a heated tank mounted on a frame equipped with wheels. Heating can be carried out using coolant oil, gas or a burner with diesel fuel. The sealing material is loaded into a tank, where it is heated to operating temperature, and then, using a pump, it is fed through heat-resistant hoses into the prepared crack.

Cracks are directly sealed through various nozzles, the size of which depends on the width of the crack being filled. If necessary, the filling nozzle can be equipped with shoes for installing a mastic plaster on the coating surface in the crack zone.

To reduce the dynamic load on the seam and reduce the adhesion of the sealant to the wheel of a passing car, it is necessary to fill only the internal cavity of the crack without spilling onto the edges.

5. Powder. Immediately after filling the crack with sealant, the repair area is covered with sand or a mixture of fine crushed stone and mineral powder.

6.1.12 For powdering, special equipment is used - a distributor. The equipment is a bunker mounted on three wheels. Moreover, the front piano wheel allows you to move exactly in the direction of the crack, and a dosing roller is mounted on the axis of the rear wheels inside the hopper. The distributor is moved manually along the sealed crack, immediately behind the pourer, while the wheels rotate the roller, dispensing crushed sand or fine crushed stone onto the surface of the mastic poured into the crack.

The powder serves to restore the overall texture and roughness of the coating, prevents mastic from sticking to the car wheels, and reduces the fluidity of the sealant immediately after filling the crack.

6.1.13 When carrying out work to rehabilitate cracks, it is necessary to ensure continuity technological process. Allowable time gaps between individual technological operations should not exceed the following values: 1 - crack cutting - up to 3 hours; 2 - crack cleaning - up to 1 hour; 3 - heating of the side walls of the crack - up to 0.5 min; 4 - crack sealing - up to 10 minutes; 5 - sprinkle the surface of the sealant with sand or fine crushed stone with mineral powder.

6.1.14 The crack rehabilitation technology is implemented by a set of equipment consisting of:

A crack separator with a diamond tool for road pavement aggregate size over 20 mm; for aggregate size up to 20 mm, cutters with carbide surfacing are used;

A mechanical brush or a wheeled tractor with a mounted brush (in cases where it is necessary to rehabilitate fairly wide and heavily contaminated cracks, they can be cleaned with disk brushes with metal bristles, brushes with a disk with a diameter of 300 mm and a thickness of 6, 8, 10 or 12 mm, the thickness should be 2-4 mm less than the width of the crack being cleaned);

Compressor;

Gas generator or heat lance. The principle of operation of the heat lance is based on the fact that compressed air from a compressor with a capacity of 2.5-5.0 m/min with a pressure of 3.5-12 kg/cm is mixed with natural gas and, in the form of a gas-air mixture, enters the combustion chamber, where it is ignited . Air heated to a temperature of 200-1300°C is supplied through a nozzle at a speed of 400-600 m/sec to the zone of the crack being treated. Gas consumption in this case is 3-6 kg/hour. A high-speed flow of compressed air, in addition to heating, effectively cleans the cavity of the crack itself and, in addition, pulls out individual destroyed particles of the coating from the area adjacent to the crack;

Melting and casting machine mounted on a vehicle chassis;

Equipment for filling a sealed crack.

6.1.15 When repairing reflected cracks, first of all it is necessary to determine whether the crack being repaired is of the reflected type. Visually reflected cracks are easy to distinguish from temperature and fatigue cracks, since they pass over the seams of the underlying cement concrete coating, as if “copying” them.

If there are cracks in the cement concrete itself, then such reflected cracks can be identified on the surface of the asphalt concrete layer using a georadar survey.

6.1.16 One of the ways to repair reflected cracks is to artificially expand its upper part to form a chamber, the width of which takes into account the maximum possible opening of the crack (usually at least 1 cm) and the relative elongation of the sealing material used.

The technology for carrying out repair work of this type is discussed in clauses 6.1.6-6.1.8.

6.1.17 Another method is to repair reflected cracks using reinforcing geogrids in combination with continuous non-woven geotextiles. In this case, the geogrid is included in the work of tension during bending, preventing the crack from opening, and the geotextile acts as a damping layer that absorbs the stresses that arise in the crack zone during temperature movements of the cement concrete slabs.

The following requirements are imposed on the geogrid: it must have high heat resistance, low creep with sufficient high temperatures laying asphalt concrete mixture (120-160°C) and good adhesion to bitumen. The cell sizes are taken depending on the composition of the asphalt concrete mixture and ensuring good adhesion between the coating layers (about 30-40 mm when using hot asphalt concrete mixtures on viscous bitumen).

The following requirements are imposed on the non-woven layer of geotextile: the density of the layer should be no more than 150-200 g/m, tensile strength 8-9 kN/m, elongation at break 50-60%.

6.1.18 Repair of reflected cracks using reinforcing geogrids in combination with non-woven geotextiles is carried out using the following technology:

Organization of traffic at the work site, installation of fences;

Cleaning the coating from dust and dirt;

Milling of the existing asphalt concrete pavement in the crack zone to a width of 30-50 cm and to the depth of the repaired layer (but not less than 5 cm);

Subpriming of the milled asphalt concrete surface with cationic bitumen emulsion in an amount of at least 1 l/m2 in terms of bitumen;

Laying a layer of geotextile to a width of 30 cm strictly symmetrically to the axis of the crack being repaired (when laying a strip of geotextile, its pre-tension of at least 3% must be ensured. The fabric is stretched by 30 cm with a strip length of 10 m);

Laying a layer of coarse-grained asphalt concrete mixture on the geotextile layer to the width of the milled crack, followed by layer-by-layer compaction with a layer thickness of 5-6 cm. If there are lower layers, compaction is carried out by tamping, the upper layer - by small rollers or vibrating plates so that the compacted surface of the asphalt concrete is flush with existing coating;

Subpriming the surface of the laid layer of asphalt concrete with bitumen emulsion in an amount of at least 0.6 l/m in terms of bitumen for a laying width of the geogrid of 150-170 cm;

Laying the geogrid sheet strictly symmetrically to the axis of the crack being repaired;

Repeated pouring of binder over the entire width of the coating surface;

Laying and compacting the top layer of a dense, fine-grained asphalt concrete mixture in a layer of at least 5-6 cm over the entire width of the pavement being repaired.

6.1.19 One of the ways to repair reflected cracks is their rehabilitation by sealing the crack with a hot, fine-grained asphalt concrete mixture with bitumen-rubber binder. This makes it possible to significantly dampen the stresses that arise above the seams of the cement concrete pavement and absorb internal plastic deformations. Rubber crumbs in the binder act as particles of the polymer component, which provide dispersed elastic reinforcement of asphalt concrete.

Asphalt concrete mixtures based on bitumen-rubber binder should be designed, depending on the type and purpose of asphalt concrete, in accordance with GOST 9128.

Technical requirements for composite bitumen-rubber binders must meet established requirements.

For composite bitumen-rubber binders, petroleum road viscous bitumens of the BN, BND grades in accordance with GOST 22245 and liquid bitumen of the MG and MGO grades in accordance with GOST 11955 are used as starting materials.

Fine crumb rubber is used, which is crumbs from general-purpose rubber, including rubber obtained by crushing worn-out car tires or other rubber technical products. The crumb must have particle sizes in the range of 0.3-0.5 mm and meet the requirements.

6.1.20 The technology for repairing reflected cracks using hot fine-grained asphalt concrete mixture with bitumen-rubber binder includes the following technological operations:

Crack cutting;

Mechanical cleaning of the crack;

Blowing out the crack with compressed air;

Warming up the side walls of the crack, priming the bottom and walls of the crack;

Sealing the crack with a hot fine-grained asphalt concrete mixture with bitumen-rubber binder;

Compaction of asphalt concrete mixture.

For compaction, a small-sized roller or vibrating plate is used.

The temperature of the asphalt concrete mixture on bitumen BND 40/60, BND 60/90, BND 90/130, BND 130/200, BND 200/300 with bitumen-rubber binder at the beginning of compaction should not be lower than 130-160 ° C for dense asphalt concrete types A and B and high-density asphalt concrete.

6.1.21 The technological sequence of work when repairing potholes consists of the following operations: cleaning the asphalt concrete surface from moisture, dirt and dust at the work site; boundary marking repair work straight lines along and across the axis of the road, covering the undamaged surface by 3-5 cm (if several closely spaced potholes are being repaired, they are combined into one contour or map); cutting - cutting or cold milling of repaired asphalt concrete along the outlined contour to the entire depth of the pothole, but not less than the thickness of the asphalt concrete layer. In this case, the side walls must be vertical; cleaning the bottom and walls of the repair site from small pieces of crumbs, dust, dirt and moisture; treating the bottom and walls with a thin layer of liquid (hot) or liquefied bitumen or bitumen emulsion, laying an asphalt concrete mixture; leveling and compacting the coating layer.

6.1.22 In the event of chipping in cement concrete pavement slabs, the resulting pothole in the overlying asphalt concrete layer can be significant in depth (more than 20-25 cm). Repair of such areas must be carried out with the removal of the entire thickness of the destroyed asphalt concrete layer, the width of the chipped surface of the cement concrete slab. Repair of a chipped surface of a cement concrete slab must be carried out in accordance with. After which the asphalt concrete mixture is laid and compacted.

6.1.23 For patching repairs of an asphalt concrete layer laid on a cement concrete pavement, it is recommended to use predominantly hot mix asphalt concrete or cast asphalt concrete of types I and II in accordance with the requirements of GOST 9128-2013 and GOST R 54401-2011, respectively.

It is recommended to use asphalt concrete mixtures that correspond in terms of strength, deformability and roughness to the asphalt concrete of the existing pavement. Hot fine-grained mixtures of types B and C should be used, since they are more technologically advanced for working with shovels, rakes and trowels in auxiliary operations than multi-crushed mixtures of type A.

To prepare hot fine-grained asphalt concrete mixtures, viscous road bitumens BND 40/60, BND 60/90, BND 90/130, BND 130/200, BND 200/300 are used in accordance with GOST 22245, as well as modified polymer-bitumen binders in accordance with OST 218.010- 98.

6.1.24 To perform edge trimming work, small milling machines, circular saws, and hammer drills are used.

Depending on the area of ​​the repaired area, cutting of the coating is carried out in various ways. Small areas (up to 2-3 m) are contoured using a seam cutter equipped with special thin (2-3 mm) diamond discs with a diameter of 300-400 mm. Then the coating inside the circuit is dismantled with jackhammers. The asphalt concrete crumbs are removed and the area is prepared for laying the asphalt concrete mixture.

6.1.25 When preparing for the repair of narrow long potholes or areas of more than 2-3 m, it is advisable to use permanently installed, trailed or mounted cutters that cut the defective coating material with a width of 200-500 mm to a depth of 50-150 mm.

If the area is large, then special high-performance road milling machines with a large width of the cut material (500-1000 mm) and a maximum depth of up to 200-250 mm are used.

6.1.26 Primer of the bottom and walls of a contoured pothole, cleared of small pieces and dust, with a thin layer of liquid (hot) or liquefied bitumen or bitumen emulsion (bitumen consumption 0═3-0═5 l/m) can be done using: a mobile bitumen heater ═ asphalt distributor═ road repairman, etc.

Small-sized units (5 hp) that pump bitumen emulsion into the spray nozzle of a hand fishing rod with a hose 3-4 m long, and units that supply emulsion from a barrel with a hand pump are effective for lubricating a pothole being repaired.

For small volumes of work and small potholes, priming with emulsion can be done from portable containers (10-20 l) with spraying with compressed air using the spray principle.

6.1.27 Laying the asphalt concrete mixture is carried out manually or using small-sized asphalt pavers. When laying the mixture manually, leveling the asphalt concrete mixture is done using improvised means (rakes and trowels).

The pothole is filled with asphalt concrete mixture in layers of 5-6 cm, taking into account the safety factor for compaction. Among the means of mechanization, a small-sized roller or vibrating plate is used for compaction. The surface of the repaired area after compaction should be at the level of the existing coating.

6.1.28 To increase the efficiency of repairing potholes with hot asphalt concrete mixture, special repair machines are used. A thermal container for hot asphalt concrete mixture with thermal insulation and heating is placed on the base machine; tank, pump and sprayer for bitumen emulsion; a compressor for cleaning and dusting repair maps, a jackhammer drive for cutting off the edges of repair maps, a vibrating plate for compacting the asphalt concrete mixture.

6.1.29 When carrying out work in conditions of increased moisture, potholes are dried with compressed air (hot or cold) before priming.

6.1.30 Repair of potholes using the jet-injection method using cationic bitumen emulsion is carried out using special trailed equipment. The pothole is cleaned for repair using a jet of compressed air or the suction method, primed with an emulsion heated to 60-75°C, and filled with crushed stone blackened during the injection process. With this repair method, cutting off the edges does not need to be done (Fig. 6.1).

Figure 6.1 - Sequence of operations for the jet-injection method of filling a pothole: 1 - cleaning the pothole with a high-speed air stream; 2 - coating the surface of the pothole; 3 - filling and compaction; 4 - dry topping

Figure 6.1 - Sequence of operations for the jet-injection method of filling a pothole: 1 - cleaning the pothole with a high-speed air stream; 2 - coating the surface of the pothole; 3 - filling and compaction; 4 - dry topping

6.1.31 Crushed stone of a fraction of 5-10 mm and an emulsion of the EBK-2 type are used as repair materials. Use a concentrated emulsion (60-70%) based on bitumen BND 90/130 or BND 60/90 with an approximate consumption of 10% by weight of crushed stone. The surface of the “seal” is sprinkled with white crushed stone in a layer of one crushed stone. Traffic opens in 10-15 minutes. Work is carried out at an air temperature of at least +5°C, both on dry and wet surfaces.

6.1.32 On roads of categories III-IV and in cases of “emergency” repairs for higher categories of roads, repair of potholes in the asphalt concrete layer on a cement concrete pavement can be carried out using wet organic-mineral mixtures (MOMS). The repair method using VOMS involves cleaning the pothole, filling it with a mixture of moistened mineral material selected composition and liquid organic binder (tar or liquefied bitumen) and compaction of the mixture. The thickness of the laid layer of material must be at least 3 cm.

The composition of VOMS consists of limestone or dolomite crushed stone of a fraction of 5...20 mm (up to 40%)═ sand with a particle size modulus of at least 1═0═ mineral powder (6...12%)═ binder (tar, liquid or liquefied viscous bitumen) in the amount 6...7% and water. Instead of crushed stone, it is allowed to use crushed screenings of crushed slag. The mixture can be prepared for future use in conventional asphalt concrete plants, retrofitted with a water supply and dosage system.

VOMS can be used at air temperatures down to -10°C and laid on the damp surface of a pothole.

6.1.33 Another method of “emergency repair” of potholes is repair using cold asphalt concrete (repair) mixtures.

This type repairs are used for pothole areas up to 1 m. Potholes are repaired immediately after they are discovered; in some cases, work can be carried out without cutting off the pothole or milling it.

Repair cold mixture consists of a mineral filler, an organic binder with the introduction of special additives. Mixing of the mixture is carried out in forced-action installations.

As an organic binder, bitumens of the BND 60/90 and BND 90/130 brands are used, meeting the requirements of GOST 33133-2014. The properties of bitumen are improved by introducing various additives with an organic solvent (thinner).

Thinners used to impart a given viscosity to the original MG 130/200 bitumen (GOST 11955-82) must meet the requirements of GOST R 52368-2005 and GOST 10585-99. The amount of thinner is 20-40% by weight of the bitumen binder and is specified by the laboratory.

In the process of preparing repair mixtures, surfactants are used to increase the adhesion strength of the binder to the surface of mineral materials and ensure the specified properties.

The temperature of the mixture should not be lower than -10°C. It is allowed to lay the repair mixture on a frozen and wet base, but in the absence of puddles, ice and snow in the area being repaired.

When repairing potholes in the pavement, depending on the depth of the destruction, the repair mixture is laid in one or two layers no more than 5-6 cm thick with each layer thoroughly compacted.

When eliminating potholes on the surface, a technological sequence is followed, which includes cleaning the damaged area, leveling and compacting the repair mixture.

Priming the surface to be repaired with bitumen or bitumen emulsion is not necessary.

The repair mixture is laid taking into account the reduction in layer thickness during compaction, for which the thickness of the applied layer should be 25-30% greater than the depth of the pothole.

When repairing potholes, depending on the area of ​​the repaired area, the mixture is compacted with a vibrating plate, a manual vibratory roller, mechanical, and for small volumes of work - with a manual tamper. If the pothole size exceeds 0.5 m, the mixture is compacted with a vibrating plate. The movement of the compacting means is directed from the edges of the area to the middle. Compaction is considered complete if there is no trace of the sealant.

The mixture is usually packaged in plastic bags weighing 20, 25, 30 kg or other quantities as agreed with the consumer. Unpackaged mixture can be stored under a canopy in open stacks on a concrete floor for 1 year. The mixture packaged in sealed bags retains its properties for two years.

6.1.34 One of the methods for repairing potholes is to seal them with cast asphalt concrete mixture. This mixture differs from the usual asphalt concrete mixture in the increased content of mineral powder (20-24%) and bitumen (9-10%) of the BND 40/60 grade. Crushed stone content - 40-45%. At a laying temperature of 200-220°C, the mixture has a cast consistency, which eliminates the need for compaction. The mixture is delivered to the work site by special vehicles with a heated container and the prepared card for pothole repair is filled with it.

After the mixture has cooled to 50-60°C, traffic is opened in the repaired area.

When installing new layers of asphalt concrete pavement, the use of cast asphalt concrete mixtures to repair potholes is not allowed. When laying new asphalt concrete layers, the cast asphalt repair cards on the underlying layers should be removed.

6.1.35 Individual defects on the surface of the asphalt concrete pavement in the form of chipping and peeling are eliminated using the jet-injection method, similar to pothole repair.

6.2 Surface treatment device on the road surface

6.2.1 The device of surface treatment on the road surface helps to increase its adhesion properties, as well as protection from wear and exposure to atmospheric factors. When applying surface treatment, the tightness of the coating increases and its service life increases. In addition, minor irregularities and defects are eliminated.

6.2.2 A single surface treatment is carried out on the surface of the asphalt concrete pavement if it has defects in the form of: peeling, spalling, cracks and small potholes.

Double surface treatment is carried out if there is a significant amount of destruction on the asphalt concrete pavement (more than 15% of total area coatings). In this case, a decision may be made to mill the top layer of the asphalt concrete pavement.

6.2.3 The installation of a single surface treatment is carried out in accordance with the Methodological Recommendations for the installation of a single rough surface treatment using equipment with synchronous distribution of bitumen and crushed stone.

6.2.4 Single surface treatment is carried out, as a rule, in the warm summer periods of the year, on a dry and sufficiently warm surface at an air temperature of at least +15°C.

Sequence of single surface treatment device:

Preparatory work;

Single surface treatment device;

Care of the surface treatment layer.

6.2.5 Preparatory work includes:

Elimination of coating defects;

Selection and preparation of crushed stone and bitumen;

Selecting the initial consumption rate of crushed stone and bitumen;

Selection and adjustment of equipment and machines that are part of a specialized detachment;

Education and training of operating personnel of machines and mechanisms.

6.2.6 In areas selected for single surface treatment, elimination of defects on the roadway is carried out in accordance with the requirements. Filling of potholes and cracks must be completed at least 7 days before the start of surface treatment.

6.2.7 The selection of the approximate consumption rate of crushed stone and bitumen for a single surface treatment device is carried out according to Table 6.1.

Table 6.1 - Selection of approximate consumption rate of crushed stone and bitumen for a single surface treatment device

Crushed stone fraction, mm	Consumption
	crushed stone, m/100 m	bitumen, kg/m

6.2.8 For surface treatment, it is recommended to use machines with synchronous distribution of binder and crushed stone (synchronous method of distribution of binder and crushed stone, Fig. 6.2).

6.2.9 The surface treatment device is carried out in the following sequence:

Cleaning the surface from dust and dirt;

Clarification of material consumption standards;

Synchronous distribution of bitumen and crushed stone on the surface of the roadway;

Compaction of the freshly laid rough layer;

Surface treatment care.

6.2.10 Cleaning the surface of the coating from dust and dirt is carried out with specialized machines with nylon, and in the case heavy pollution surfaces - with a metal brush and watering equipment. The coating is cleaned in two to five passes along the track.

Figure 6.2 - Synchronous distribution of binder and crushed stone during surface treatment

Figure 6.2 - Synchronous distribution of binder and crushed stone during surface treatment

6.2.11 Compaction of the freshly laid layer is carried out immediately after the passage of the machine with synchronous distribution of binder and crushed stone. Carry out 5-6 passes of a self-propelled roller on pneumatic wheels on the surface with a wheel load of at least 1.5 tons and a tire pressure of 0.7-0.8 MPa, or a roller with rubber-coated metal rollers. The final formation of the layer occurs under the influence of passing motor transport with a speed limit of up to 40 km/h. The period of formation of a freshly laid layer should be at least 10 days.

6.2.12 Maintenance of freshly laid surface treatment includes the following operations:

Speed ​​limit to 40 km/h;

Regulation of traffic across the entire width of the roadway using guide fences;

Cleaning up unrooted crushed stone with the brush of a watering machine no later than one day after completion of compaction;

Additional compaction with a roller.

6.2.13 When using a single surface treatment in a synchronous manner, the time interval between pouring bitumen and distributing crushed stone is less than 1 s. This provides a significant improvement in the adhesive quality of the binder, by penetrating it into the micropores of crushed stone. In this case, the crushed stone adheres well to the surface of the coating. With the synchronous distribution of binder and crushed stone, the quality of surface treatment is significantly improved, both when using hot bitumen and bitumen emulsion as a binder.

6.2.14 Work on installing double surface treatment is carried out on a clean, dust-free surface of the coating, dry when using bitumen and moistened when using bitumen emulsions. The air temperature when using bitumen as a binder should not be lower than +15°C, and when using bitumen emulsion - not lower than +5°C. In some cases, if it is impossible to ensure the required cleanliness of the milled coating, it is recommended to prime it by pouring liquid bitumen at a rate of 0.3-0.5 l/m.

6.2.15 The technological process of the double surface treatment device includes:

Milling of asphalt concrete pavement;

Cleaning the milled surface from dust and remaining asphalt chips;

Priming the coating surface (if necessary);

The first pouring of bitumen binder is 1.0...1.2 l/m and distribution of processed crushed stone of the 20...25 mm fraction in an amount of 20...25 kg/m, followed by rolling the layer with two or three passes of a light roller (5...8 t);

The second filling of binder at a rate of 0.8...0.9 l/m;

Distribution of processed crushed stone fraction 10…15 mm (13…17 kg/m) followed by compaction with four to five passes of a light roller.

6.2.16 The approximate costs of binder and crushed stone when distributed on the coating are given in Table 6.2.

Table 6.2 - Consumption of binder and crushed stone (excluding pre-treatment)

Crushed stone size, mm	Consumption rate
	crushed stone, m/100 m	bitumen, l/m	emulsion, l/m, at bitumen concentration, %
Single surface treatment
Double surface treatment
	First placer	First bottling
	Second placer	Second bottling
Note - When using black crushed stone, the binder consumption rates are reduced by 20-25%.

6.2.17 The decision on pre-treatment of crushed stone with a binder in the installation (blackening of crushed stone) is made based on the results of laboratory studies of the adhesion of crushed stone to the binder in accordance with GOST 12801-98 *. For blackening, it is recommended to use bitumen grades BND 60/90, BND 90/130, BND 130/200, MG 130/200, MG 70/130.

6.2.18 The main pouring of the binder is carried out on half of the roadway in one go, without gaps or breaks. If it is possible to provide a detour, the binder is poured over the entire width of the roadway.

6.2.19 The temperature of the bitumen during its distribution should be within the following limits: for viscous bitumen grades BND 60/90, BND 90/130 - 150160°C; for grades BND 130/200 - 100130°C; for polymer-bitumen binders - 140-160°C.

6.2.20 When applying surface treatment using bitumen emulsions, cationic emulsions EBK-1, EBK-2 and anionic emulsions EBA-1, EBA-2 are used. When applying surface treatment using cationic bitumen emulsions, crushed stone is used that has not been pre-treated with organic binders. When using anionic emulsions - predominantly black crushed stone.

6.2.21 The temperature and concentration of the emulsion are set depending on weather conditions:

At an air temperature below 20°C, the emulsion should have a temperature of 4050°C (with a bitumen concentration in the emulsion of 55-60%). The emulsion is heated to this temperature directly in the asphalt distributor;

At air temperatures above 20°C, the emulsion does not need to be heated (at a bitumen concentration in the emulsion of 50%).

6.2.22 Immediately after scattering the crushed stone, it is compacted with smooth rollers weighing 6-8 tons (4-5 passes along one track). Then with heavy smooth rollers weighing 10-12 tons (2-4 passes along one track). For better manifestation of the rough structure, it is advisable to carry out the final stage of compaction using smooth rollers with rubber-coated rollers.

6.2.23 When using bitumen emulsions, work is carried out in the following sequence:

Wetting the treated coating with water (0.5 l/m);

Pouring emulsion over the coating in an amount of 30% of consumption;

Distribution of 70% of crushed stone from the total consumption (gap of no more than 20 m with a time interval of no more than 5 minutes from the moment of pouring the emulsion);

Pouring the remaining emulsion;

Distribution of the remaining crushed stone;

Compaction with rollers weighing 6-8 tons, 3-4 passes along one track (the beginning of compaction should coincide with the beginning of the disintegration of the emulsion);

Maintenance of the constructed surface.

6.2.24 When using cationic bitumen emulsions, vehicle traffic is opened immediately after compaction. Maintenance of double surface treatment is carried out for 10...15 days, by regulating traffic along the width of the road surface and limiting the speed to 40 km/h.

In the case of using an anionic emulsion, traffic should be opened no earlier than one day after the surface treatment device.

6.3 Installation of thin friction wear-resistant protective layers on the surface of the road surface

6.3.1 Construction of thin protective layers of cast emulsion-mineral mixtures

6.3.1.1 Thin friction wear-resistant protective layers made from cast emulsion-mineral mixtures (LEMS) are used as friction and waterproofing wear layers to increase the service life of road surfaces and improve driving conditions. Wear layers are primarily necessary to restore the performance of coatings.

6.3.1.2 When repairing asphalt concrete layers laid on a cement concrete pavement, the following options for using cast emulsion-mineral mixtures are possible:

1) laying LEMS on upper layer asphalt concrete pavement;

2) laying LEMS on a milled asphalt concrete surface.

6.3.1.3 Before installing the LEMS layer, the coating is primed with emulsion or bitumen grades BND 200/300 at the rate of 0.3-0.4 l/m (in terms of bitumen).

6.3.1.4 Preparation and installation of LEMS is carried out using special single-pass machines that mix materials and distribute the mixture over the surface of the coating.

It is recommended to use crushed stone of various fractions up to 15 mm from igneous and metamorphic rocks with a strength of at least 1200. The sand fraction of 0.1 (0.071)-5 mm consists of crushed sand or a mixture of natural and crushed sand in equal parts. For mineral powder (preferably activated) from carbonate rocks, it is assumed that the total number of particles finer than 0.071 mm contained in the mixture is 5-15%. The binder is used in the form of cationic bitumen emulsions of the EBK-2 and EBK-3 classes, containing 50-55% bitumen. The compositions of LEMS are given in Table 6.3.

Table 6.3 - Compositions of cast emulsion-mineral mixtures

Mixture type	Number of components,% by weight
	granite crushed stone, mm				mine- ral- porous shock	Portland- cement	water for pre- body wetting	bitumen emulsion (in terms of bitumen)
			crushed ny	nature ny
Crushed stone
Sandy
			[email protected], we'll figure it out.

Smooth, high-quality road surfaces that provide full adhesion of vehicle wheels to the road surface are the key to safe and quiet road traffic. Due to active use, roads are constantly in need of repair and renewal.

Currently the most popular view road surface repair is pothole repair. This method is used more often than others, because it is much more profitable, economical and faster. However, there are many complaints about it from car drivers who swear about the quality of road surfaces and the rapid destruction of patches after repairs. But here the reason may not lie in the technology itself, but in those who use it. The quality of such repairs depends on compliance with the pothole repair technology. Quite often, careless workers do not even pay attention to the conditions and requirements that must be observed in the process of road repairs, so unscrupulous and careless attitude towards work often becomes the cause of destruction of road surfaces.

Advantages

Road patching does not imply any work to restore communications or improve areas: asphalt is laid only in areas that need urgent repairs. In addition, it should be noted that similar works must be carried out in strict compliance with all points of the technological process. This guarantees cost savings, durability and maximum quality. Pothole repair allows you to restore the continuity, strength, evenness, adhesion and water resistance of coatings. In addition, it ensures the standard service life of the sections.

Pothole repair has been relevant for decades. There are dozens of technologies for carrying out such repairs of road surfaces, while the best way is selected based on weather conditions, the condition of the canvas, the possibilities of full use of special equipment and the specifics of the materials used. Pothole repair of road surfaces has several undeniable advantages:

• there is no need to completely block traffic on the motorway/highway;
• prompt implementation of all necessary work(small areas are restored within 24 hours);
• no need to use heavy special equipment;
• Pothole repair of asphalt pavement does not require huge financial costs (compared to major repairs).

Recipe for success

Usually, unscrupulous workers repair only the top layer of damaged areas. However, in fact, the pothole repair technology involves the restoration of the underlying layer.

Before starting work, the boundaries of damage are determined, existing defects are identified, potential defects are determined, the scale of work and indicators of reliability, uniformity, strength and roughness of coatings are calculated.

Asphalt rolling

Many domestic enterprises that carry out road repairs and construction have rollers weighing from 8 tons. Such road equipment is justified for full-scale work, but it is not practical to use it for pothole repair. To compact several tens of meters of road, it is better to use the “trampling” method, which is implemented using manual vibrating plates. Asphalt patching is also carried out using small sidewalk or vibrating rollers.

Traditional method

With this repair method, the damaged area is first separated from the coating, this is done using a road milling machine. Then the edges of the potholes are cut off to give them a rectangular shape. Then the defective sector is cleaned from dust and crumbs; its edges and bottom are treated with liquid bitumen emulsion or heated bitumen, after which the asphalt concrete mixture is poured.

Pothole repair of road surfaces, the technology of which is traditional, allows you to obtain high-quality work results, but it requires a significant number of operations. It is used in the process of repairing various types of coatings made of bitumen-mineral and asphalt concrete materials.

Repair with heating of coatings and reuse of its material

Such road pothole repair is based on the use of special equipment for heating the surfaces - an asphalt heater. This method allows you to obtain high-quality results, save on materials, and facilitate the technology of performing work. But at the same time, pothole repair of asphalt concrete pavement has significant limitations due to weather conditions (air temperature and wind). This method is used in the process of repairing various types of coatings made from bitumen-mineral and asphalt concrete mixtures.

Repair without cutting down or heating the old coating

Destructions and deformations of road surfaces are filled with cold polymer-asphalt concrete mixture, wet organomineral mixture, cold asphalt concrete, etc. The method allows work to be carried out in cold weather with wet and damp surfaces, is simple to implement, but is not capable of ensuring high quality and durability of coatings. This method is used in the process of repairing road surfaces with low traffic intensity, temporary, and also as an emergency measure on roads with increased intensity.

Cold methods of pothole repair

This is a pothole repair of the road surface, the technology of which is based on the use of cold asphalt concrete or bitumen-mineral mixtures as repair material. These methods are used mainly in the process of repairing cold asphalt concrete and on low-category roads and when it is necessary to temporarily or urgently repair potholes.

Work begins in the spring at an air temperature of at least +10 degrees. At the repair site, the coating is formed under the influence of moving transport for 20-40 days, and its quality depends on the properties of the bitumen emulsion or liquid bitumen, the composition and intensity of traffic, and the weather.

Repairs can also be carried out with low temperatures, while repair materials are prepared in advance. The cost of repairs using this technology is less than with the hot method. The main disadvantage is the short service life of coatings on roads with buses and heavy trucks.

Hot ways

They are based on the use of hot asphalt concrete mixtures as materials: cast asphalt concrete, coarse- and fine-grained, sand, etc.

The methods are used when repairing roads with asphalt concrete surfaces. It is possible to perform work at air temperatures of at least +10 degrees with a dry coating and a thawed base. When using a heater, repairs are allowed at a temperature of at least +5 degrees.

Hot methods provide higher quality and longer service life of coatings.

Preparatory operations

Before carrying out work, the following preparatory operations are performed:

1. Fencing of places is installed, road signs and lighting devices when carrying out work in dark time days.
2. Repair locations (maps) are marked using chalk or a stretched cord. The repair map is drawn with straight lines perpendicular and parallel to the axis of the road, giving the correct shape to the contour and capturing the undamaged surface.
3. Damaged coatings are cut down, broken or milled, and the removed material is removed. It is carried out to the thickness of the destroyed coating layer, but not less than 4 centimeters along the entire length of the repair. When a pothole affects the bottom layer, it is loosened and removed to its full thickness.
4. Potholes are cleared of material residues, dirt and dust.
5. The walls and bottom are dried when performing repairs using the hot method.
6. The walls and bottom are treated with bitumen or bitumen emulsion.

Basic Operations

Only after preparation can potholes be filled with repair material. The installation technique and sequence of procedures depend on the volume and method of work, and the type of repair material.

For small volumes and the absence of mechanized means, laying can be done manually. The mixture is laid into the card in 1 layer when cutting to a depth of up to 50 millimeters and in 2 layers when cutting to a depth of more than 50 millimeters. In this case, a coarse-grained mixture of crushed stone can be laid in the bottom layer, and a fine-grained mixture in the top layer.

With mechanized laying, the mixture is supplied from a thermos hopper.

When sealing cards 10-20 sq. m asphalt concrete mixtures are laid with an asphalt paver. In this case, the installation is carried out in a pothole, and the mixture is evenly leveled over the entire area.

Compaction in the lower layer of the coating is carried out using pneumatic rammers, manual vibratory rollers or electric rammers in the direction from the edges to the middle.

The mixture laid in the top layer and the mixture laid in 1 layer at a depth of up to 50 millimeters is compacted with self-propelled vibratory rollers or light smooth static rollers, and then with heavy rollers.

For low-gravel and sandy soils it should be no less than 0.98, for high- and medium-gravel soils - 0.99.

Hot mixtures are compacted when maximum temperatures, in which deformation during rolling is impossible.

Joints that protrude above the surface of the coating are removed using grinding or milling machines.

Final operations

Final operations involve measures to make the road surface ready for movement. Vehicle. Workers remove the remaining waste and garbage and load it into dump trucks. Also at this stage, road signs and fences are removed, and the marking line in the patching area is restored.

Important Requirements

The quality and service life of repaired coatings primarily depend on compliance with the following requirements:

• pothole repair is carried out at air temperatures no less than permissible for a specific repair material on a clean and dry surface;
• in the process of cutting down the old coating, weakened material is removed from all areas of the pothole where there are breaks, cracks and spalling;
• it is necessary to clean and dry the repair card;
• must be done correct forms maps, sheer walls, flat bottom;
• All surfaces of the pothole must be treated with a binder;
• laying of repair material is carried out when optimal temperature for this type of mixture;
• the layer should have a thickness slightly greater than the depth of the pothole, taking into account the margin for compaction coefficient;
• the formation of a layer of new materials on old coatings at the edge of the map is unacceptable in order to avoid shocks when vehicles collide and rapid destruction of areas;
• the repair material is well leveled and compacted flush with the road surface.

Quality control

Polymerization of asphalt concrete occurs at temperatures above 100 degrees and under high pressure. Once the mixture is compacted, the asphalt is not afraid of water. On the contrary, it is advisable to water the restored road surfaces with water to quickly cool and restore traffic flow.

It should be noted that if the technology is not fully compliant and certain rules are violated, the asphalt concrete patches made can last at least 2 years. With strict adherence to repair techniques - at least 5 years.

The carriageway of the road must comply (after patching has been carried out) with GOST R 50597-93 - “Motor roads and streets”.