PPR for patching the road with cold asphalt. The use of asphalt, the technology of its laying and repair

15.06.2019

According to the official legal documents (SNiPam), which regulate asphalt laying standards, it is possible to carry out asphalting of roads only at a temperature of +5 С°. How to carry out urgent road repairs in winter period? New technologies come to the rescue of road services.

Asphalt is more expensive in cold weather

In the cold Russian climate temperature regime asphalt laying is broken every now and then, which leads to a significant deterioration in the quality of the created road surface and an increase in the cost of seasonal and overhaul. In an effort to complete the work on time, contractors carry out road construction at sub-zero temperatures and high humidity. After the mixture hardens, moisture that has entered the smallest pores and cracks of the new coating quickly turns into ice under the influence of low temperatures. The volume of frozen water increases by about 8-9%, due to which, during periods of severe cold, one can observe bursting water pipes and various liquid containers. The same expansion effect causes ice-filled cracks in the asphalt concrete to increase in size and erode the pavement from the inside.

An additional problem is also the adhesion between the individual layers of pavement laid at low temperatures or in the rain. According to experts, even constant heating and drying of the soil base with special devices does not allow 100% to get rid of moisture that prevents high-quality adhesion of pavement layers. In accordance with modern standards, the only type of asphalt paving that can be carried out under almost any weather conditions (excluding very coldy), remains patching using special mixtures.

"Cold technologies": does the quality match the price?

The use of cold mix asphalt today is one of the most modern technologies emergency patching during the cold season. Unlike traditional hot asphalt, cold asphalt concrete contains elastic bitumen, the viscosity of which increases with decreasing ambient temperature. The formula of the brands on the market is constantly being improved, including special composite additives that improve the adhesion of the mixture to the substrate and guarantee increased ease of installation and durability. Under pressure during rolling and further operation of the road, cold asphalt finally polymerizes and acquires significant hardness.

Consider the advantages and disadvantages of cold mixes in comparison with conventional hot asphalt.

pros

Ready-made cold mixes can be stored without loss of their properties for up to 1 year, which allows you to always have ready-made material for urgent work;
The minimum temperature for cold asphalt paving is from -20°C to -25°C according to various suppliers;
A cold repaired track can be opened to traffic immediately after paving. Under the weight of the transport, the cold mixture is finally compacted and becomes more durable;
Laying cold asphalt does not require expensive special equipment and special vehicles for transporting the material.

Minuses

"Cold laying" can only be used for small potholes and pits;
A "patch" made from a cold mixture is easily shearable and breaks down faster in braking areas - crossroads, pedestrian crossings, etc.;
Fresh asphalt areas adjacent to unused areas of the road (strips at the edge of the curb, around hatches and other technical objects) are not sufficiently compacted by the wheels of cars and are destroyed faster;
The price of cold mixes is many times higher than the price of ordinary hot asphalt (the cost of 1 ton of imported cold asphalt is about 60 thousand rubles, 1 ton of standard asphalt is about 2.5 thousand rubles).

Hot casting: an expensive alternative

Molded asphalt differs from the standard one in the presence of high-viscosity hard bitumen and mineral inclusions (sand, fine gravel). Work with hot mixes is carried out at temperatures from +200 ° C, due to which patching of highways can be carried out at high humidity and low temperatures. The cost of the material is somewhat lower than the price of cold mixes, however, poured asphalt requires additional costs for the rental of special equipment. Due to excessive ductility during the hot summer season, hot casting is considered a temporary emergency repair method.

Compared with conventional hot asphalt, cast asphalt has the following advantages and disadvantages:

pros

Once poured, the hot mix compacts itself during the curing process, eliminating the need for an asphalt roller;
Molded asphalt has exceptional adhesive properties and forms a strong bond with the base even at low temperatures and high humidity;
The ability to carry out urgent repairs at sub-zero temperatures and during precipitation.

Minuses

Transportation of a hot mixture requires expensive road equipment (boilers and cohlers), which allows maintaining a consistently high temperature of the material and constantly mixing it;
Road repair with poured asphalt requires high costs energy (the required temperature during laying is about +200 C °);
In the warm season, “patches” can heat up in the sun up to +60 ° C and squeeze through under the wheels of cars.

Summing up, it can be noted that today the most modern and universal method of patching under any weather conditions is the use of cold asphalt mixtures. According to some experts, in the coming years, further improvement of the cold asphalt formula will make it possible to effectively carry out emergency road repairs even at extremely low temperatures. But the high-quality construction of roads in the cold season is still a matter of the future - at the moment there are no materials and technologies on the market that allow, at high humidity and sub-zero temperatures, to create a durable asphalt pavement that meets all the necessary standards.

Smooth high-quality road surfaces, which provide full grip of the wheels of the vehicle with the canvas, are the key to safe and quiet road traffic. Due to the active use of the road, it is constantly in need of repair and renovation.

Pothole repair is currently the most popular type of road surface repair. This method is used more often than others, because it is much more profitable, economical and faster. However, it also has a lot of complaints 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 patching technology. Quite often, negligent workers do not even pay attention to the conditions and requirements that must be observed in the process of road repair, so an unscrupulous and careless attitude to work more often causes the destruction of road surfaces.

Advantages

Pothole repair of the road does not imply any work on the restoration of communications, landscaping: asphalt is laid only in areas that need urgent repairs. In addition, it should be noted that such work must be carried out in strict observance of all points technological process. This guarantees cost savings, durability and maximum quality. Patching allows you to restore the continuity, strength, evenness, adhesion and water resistance of coatings. In addition, it provides normative term site services.

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

there is no need for a complete blocking of traffic on the freeway / highway;
prompt implementation of all necessary work (small areas are restored within a day);
no need to involve heavy special equipment;
patching asphalt pavement does not require huge financial costs(compared to overhaul).

Recipe for success

Usually unscrupulous workers repair only upper layer damaged areas. However, in fact, patching 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 repair and build roads have rollers weighing 8 tons or more. Such road equipment is justified for full-scale work, but it is not advisable to use it for patching. To compact several tens of meters of the road, it is better to use the “trampling” method, which is implemented using manual vibrating plates. Asphalt patching is also carried out using small pavement or vibratory rollers.

traditional method

With this method of repair, the damaged area is first separated from the coating, this is done with the help of a road mill. Then the edges of the potholes are cut off, giving them rectangular outlines. 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.

Patching the pavement, the technology of which is traditional, allows you to get a high-quality result of work, but it requires a significant number of operations. It is used in the repair process. various kinds coatings from bituminous mineral and asphalt concrete materials.

Repair with heating of coatings and re-use of its material

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

Repair without cutting or heating the old coating

Destruction and deformation of road surfaces are filled with cold polymer-asphalt concrete mixture, wet organo-mineral mixture, cold asphalt concrete, etc. The method allows you to work in cold weather with wet and wet pavement, is simple in execution, but is not able to provide high quality and durability of pavements. 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 patching techniques

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 a repair material. These methods are used mainly in the process of repairing cold asphalt concrete and on low-grade roads and when temporary or urgent repair of potholes is necessary.

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

Repairs can also be carried out at 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 the movement of buses and heavy trucks.

hot ways

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

The methods are used in the repair of roads with asphalt concrete pavement. 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, preparatory operations are performed:

Fencing places, road signs and lighting devices are installed when work is carried out at night.
Places (maps) of repair are marked with chalk or a stretched cord. The repair map is outlined with straight lines perpendicular and parallel to the axis of the road, giving the correct shape to the contour and capturing the undamaged pavement.
Damaged coatings are cut, broken or milled, the removed material is removed. It is carried out for the thickness of the destroyed layer of coatings, but not less than 4 centimeters along the entire length of the repair. When the pothole affects the lower layer, it is loosened and removed to the full thickness.
Potholes are cleaned of material residues, dirt and dust.
The walls and bottom are dried when performing hot repairs.
The walls and bottom are treated with bitumen or bitumen emulsion.

Basic operations

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

With small volumes and the absence of mechanized means, stacking can be done manually. Laying the mixture is carried out in a card in 1 layer when cutting down to a depth of 50 millimeters and in 2 layers at a depth of more than 50 millimeters. At the same time, a coarse-grained mixture of crushed stone can be laid in the lower layer, and a fine-grained mixture in the upper one.

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

When sealing cards 10-20 sq. m asphalt mixes are laid by an asphalt paver. In this case, laying 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 by 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 by self-propelled vibratory rollers or light-type smooth-roller static rollers, and then by heavy rollers.

For low gravel and sandy it should be at least 0.98, for many and medium gravel - 0.99.

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

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

Final operations

The final operations involve measures to bring the road surface ready for movement. Vehicle. Workers remove the remaining waste, garbage, immerse them in dump trucks. Also at this stage, road signs and fences are removed, the marking line is restored at the patching site.

Important requirements

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

patching is carried out at air temperatures not less than the permissible for a certain 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 chipping;
it is necessary to clean and dry the repair card;
it is necessary to make the correct forms of the map, sheer walls, a flat bottom;
all surfaces of the pothole must be treated with an astringent composition;
the laying of the repair material is carried out at the optimum 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 the compaction factor;
the formation of a layer of new materials on old coatings at the edge of the map is unacceptable in order to avoid jolts when vehicles run over and the rapid destruction of areas;
the repair material is well leveled and compacted flush with the road surface.

Quality control

The polymerization of asphalt concrete proceeds at a temperature of more than 100 degrees and under high pressure. After compaction of the mixture, the asphalt is not afraid of water. On the contrary, it is desirable to water the restored roadbeds with water for rapid cooling and restoration of traffic.

It should be noted that in case of incomplete compliance with the technology and violation of some rules, the asphalt concrete patches made can last at least 2 years. With strict observance of the repair technique - at least 5 years.

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

ODM 218.3.060-2015

INDUSTRY ROAD GUIDELINE

Foreword

1 DEVELOPED by the Federal State Budgetary Educational Institution of 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 Highway Agency

5 INTRODUCED FOR THE FIRST TIME

1 area of use

2 Normative references

Thermal cracks occur as a result of cooling and resistance of the coating 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 is bent from multiple transport loads develop from the bottom up from the base to the surface of the coating.

Reflected cracks replicate seams or cracks in cement concrete pavements and are most characteristic of asphalt concrete layers laid on a cement concrete pavement. With a decrease in temperature, the deformation of the cement concrete coating occurs in the form of a shortening of the slabs. As a result, joints or cracks in the cement concrete pavement expand, which leads to stretching and rupture of the overlying layers of asphalt concrete with the formation of reflected cracks. To these tensile stresses are added their own tensile stresses from a decrease in the temperature of the asphalt concrete. This is a time cyclic process leading to the destruction of the asphalt concrete pavement.

By width, cracks are classified into narrow (up to 5 mm), medium (5-10 mm) and wide (10-30 mm). This classification is typical for thermal and fatigue cracks. For reflected cracks, this approach is incorrect, due to the presence of thermal deformations of the underlying cement concrete pavement causing the crack edges to move 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 of their repair and the composition of the equipment used are selected. The main task in the repair of cracks is to prevent the penetration of water through them into the underlying layers of the pavement. Waterproofing of 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 main 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 with compressed air, dried, heated and filled with bituminous emulsion or mastic with high penetrating power.

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 the coating from chipping at the edges of the crack. It is smoothed out with a special heating iron (shoe) and sprinkled with fractionated sand. The coating in the crack zone is preliminarily dried with a heated jet of compressed air.

6.1.6 If the 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 with the formation of a chamber in which the sealing material performs optimally in tension during the crack opening.

6.1.7 The width of the chamber must not be 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 width of the chamber is in the range of 12-20 mm.

6.1.8 If the temperature or fatigue crack is not cut to the 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 is placed in the crack at the bottom of the chamber 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 the width of the chamber of the split crack.

The depth of the groove after pressing the sealing cord (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 bituminized sand is used, coarse and medium sand is used that meets the requirements of GOST 8736-2014 and GOST 11508-74 *.

Rubber crumb 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 stickiness temperature and the 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 when the edges of a temperature or fatigue crack have not been destroyed and it is possible to 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 sealing cracks is the presence of good adhesion of the sealant to the walls of an uncut crack or a milled chamber. In this connection, much attention is paid to the preparatory work for cleaning and drying the crack. To improve adhesion, the walls of the milled chamber are primed with a primer - a low-viscosity film-forming (gluing) liquid.

6.1.11 The main technological operation in the repair of temperature or fatigue cracks is their filling with hot mastic. The mastic is preheated to a temperature of 150-180°C, after which it is fed into an arranged 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, arrange a patch on the surface of the coating in the crack zone. Such a patch 6-10 cm wide and 1 mm thick makes it possible to strengthen the edges of the crack and prevent their destruction.

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

The method of rehabilitation of medium and wide temperature or fatigue cracks in 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 edge damage when cutting a crack in an asphalt concrete pavement, it is necessary to take into account the composition of asphalt concrete when choosing a cutting tool. With a grain size of crushed stone of 20 mm or more, it is recommended to use a diamond tool, and with a grain size of up to 20 mm, hard-faced cutters can be used.

2. Removal of destroyed asphalt concrete. For this, a high performance compressor is used. For thorough cleaning both from the dust that appeared as a result of cutting, and to remove deposits remaining in the depth of the crack.

3. Drying and warming up. The split cavity of the crack is dried and heated by the so-called thermal spear.

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

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

4. Filling the crack cavity with sealant. In the cleaned, dried and heated cavity of the butchered crack, bituminous mastic from a melting machine.

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

Direct sealing of cracks is carried out 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 installation on the surface of the coating in the area of the crack in the mastic patch.

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 inner cavity of the crack without spilling on the edges.

5. Powder. Immediately after filling the crack with sealant, the repair site is covered with sand or a mixture of fine gravel with mineral powder from above.

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, dosing crushed sand or fine gravel onto the surface of the mastic poured into the crack.

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

6.1.13 When carrying out work on the rehabilitation of cracks, it is necessary to ensure the continuity of the technological process. Permissible 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 min; 5 - powdering the surface of the sealant with sand or fine gravel with mineral powder.

6.1.14 Crack repair technology is implemented by a set of equipment consisting of:

Crack splitter with a diamond tool with a pavement aggregate size of more than 20 mm, with a filler size of up to 20 mm, cutters with hard-alloy surfacing are used;

A mechanical brush or a wheeled tractor with a mounted brush (in the case when it is necessary to rehabilitate sufficiently wide and heavily contaminated cracks, they can be cleaned with disc brushes with metal bristles, brushes with a disc 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 to be cleaned);

compressor;

Gas generator installation or thermal lance. The principle of operation of the thermal lance is based on the fact that compressed air from a compressor with a capacity of 2.5-5.0 m/min at a pressure of 3.5-12 kg/cm is mixed with natural gas and enters the combustion chamber in the form of a gas-air mixture, where it is ignited . Air heated to a temperature of 200-1300°C is fed through a nozzle at a speed of 400-600 m/s into the treated crack zone. The gas consumption in this case is 3-6 kg/hour. A high-speed compressed air flow, 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 pouring machine mounted on a car chassis;

Equipment for filling a sealed crack.

6.1.15 When repairing reflected cracks, first of all, it is necessary to establish whether the repaired crack belongs to the reflected type. Visually reflected cracks are easy to distinguish from temperature and fatigue cracks, as they pass over the joints of the underlying cement concrete pavement, as if "copying" them.

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

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

The technology for the production of repairs of this type is considered in paragraphs 6.1.6-6.1.8.

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

The following requirements are imposed on the geogrid: it must have high thermal stability, low creep at sufficiently high temperatures for laying the asphalt concrete mixture (120-160°C) and good adhesion to bitumen. Cell sizes are taken depending on the composition of the asphalt mix and ensuring good adhesion between the layers of the coating (about 30-40 mm when using hot asphalt mixes on viscous bitumens).

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

6.1.18 Repair of reflected cracks using reinforcing geogrids in combination with non-woven geotextiles is carried out according to 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);

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

Laying a layer of geotextile to a width of 30 cm strictly symmetrical to the axis of the crack being repaired (when laying a strip of geotextile, its pre-tension should be at least 3%. The sheet 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. existing coverage;

Priming the surface of the laid layer of asphalt concrete with a bitumen emulsion in an amount of at least 0.6 l/m2 in terms of bitumen for a geogrid laying width of 150-170 cm;

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

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

Laying and compaction of the top layer of the coating of dense fine-grained asphalt concrete mixture with a layer of at least 5-6 cm over the entire width of the repaired coating.

6.1.19 One of the ways to repair reflected cracks is their sanitation with crack filling with hot fine-grained asphalt concrete mixture with bitumen-rubber binder. This makes it possible to largely extinguish the stresses arising above the joints of the cement concrete pavement and absorb internal plastic deformations. Rubber crumb in the composition of the binder acts as particles of the polymer component, which carry out the dispersion-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 to composite bitumen-rubber binders must comply with the established requirements.

For a composite bitumen-rubber binder, viscous oil road bitumen grades BN, BND according to GOST 22245 and liquid bitumen grades MG and MGO according to GOST 11955 are used as initial ones.

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

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

Crack cutting;

Mechanical cleaning of the crack;

Blowing out the crack with compressed air;

Heating of the side walls of the crack, priming of the bottom and walls of the crack;

Crack filling with hot fine-grained asphalt concrete mixture with bitumen-rubber binder;

Compaction of asphalt mix.

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 Technological sequence of work, when repairing potholes, consists of the following operations: cleaning the asphalt concrete pavement from moisture, dirt and dust at the work site; border marking repair work in straight lines along and across the axis of the road with a grip of 3-5 cm of undestroyed pavement (if several closely spaced potholes are being repaired, they are combined with one contour or map); cutting═ cutting or cold milling of the 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═ crumbs═ dust═ dirt and moisture; treatment of the bottom and walls with a thin layer of liquid (hot) or liquefied bitumen or bitumen emulsion, laying the asphalt concrete mixture; leveling and compaction of the coating layer.

6.1.22 In the event of the formation of chips in the cement concrete pavement slabs, the pothole formed as a result of this in the overlapping 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 destroyed layer of asphalt concrete to the full thickness, to the width of the surface of the chipped cement concrete slab. Repair of a chipped surface of a cement concrete slab must be carried out in accordance with. After that, the asphalt concrete mixture is laid and compacted.

6.1.23 For patching of an asphalt concrete layer laid on a cement concrete pavement, it is recommended to use mainly hot mix asphalt 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 work with shovels, rakes and trowels in auxiliary operations than multi-gravel mixtures of type A.

For the preparation of hot fine-grained asphalt concrete mixtures, viscous road bitumen BND 40/60, BND 60/90, BND 90/130, BND 130/200, BND 200/300 according to GOST 22245, as well as modified, polymer-bitumen binders according to OST 218.010- 98 .

6.1.24 To perform edge trimming, small milling machines, circular saws, and perforators are used.

Depending on the area of the repaired area, trimming of the coating is performed in various ways. Small areas (up to 2-3 m) are contoured using a seam saw equipped with special thin (2-3 mm) diamond discs with a diameter of 300-400 mm. Then, with jackhammers, the coating inside the circuit is disassembled. The asphalt crumb is removed and the site is prepared for laying the asphalt concrete mixture.

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

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

6.1.26 Priming of the bottom and walls of a contoured pothole═ cleaned 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 performed using: ═ asphalt distributor═ road repairer, etc.

Effective for lubricating a repaired pothole are small-sized installations (5 hp) ═ pumping bituminous emulsion into the spray nozzle of a hand-held fishing rod with a hose 3-4 m long, installations supplying emulsion from a barrel with a manual pump.

For small volumes of work and small potholes, emulsion priming can be carried out from portable containers (10-20 l) with spraying with compressed air according to the principle of a spray bottle.

6.1.27 The asphalt mix is laid manually or using small-sized asphalt pavers. When laying the mixture manually, the leveling of the asphalt concrete mixture is carried out with 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. Of the means of mechanization for compaction, a small-sized skating rink or a vibrating plate is used. The surface of the repaired area after compaction should be at the level of the existing pavement.

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

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

6.1.30 Repair of potholes by the jet-injection method using a cationic bitumen emulsion is carried out using trailed special equipment. Cleaning the pothole for repair is carried out with a jet of compressed air or by suction, priming - with an emulsion heated to 60-75 ° C, filling - with crushed stone blackened during injection. With this repair method, edge trimming can be omitted (Fig. 6.1).

Figure 6.1 - The sequence of operations for the jet-injection method of filling the pothole: 1 - cleaning the pothole with a high-speed air jet; 2 - coating the surface of the pothole; 3 - filling and sealing; 4 - dry dressing

Figure 6.1 - The sequence of operations for the jet-injection method of filling the pothole: 1 - cleaning the pothole with a high-speed air jet; 2 - coating the surface of the pothole; 3 - filling and sealing; 4 - dry dressing

6.1.31 As a repair material, crushed stone of a fraction of 5-10 mm and an emulsion of the EBK-2 type are used. A concentrated emulsion (60-70%) based on bitumen BND 90/130 or BND 60/90 is used with an approximate consumption of 10% by weight of crushed stone. The surface of the "seal" is sprinkled with white crushed stone with a layer of one crushed stone. The traffic opens in 10-15 minutes. Works are carried out at an air temperature not lower than + 5 ° C, both on dry and wet surfaces.

6.1.32 On roads III-IV categories and in cases of "emergency" repairs for higher categories of roads, the repair of potholes in the asphalt concrete layer on the cement concrete pavement can be carried out using wet organic-mineral mixtures (WOMS). The repair method using FOMS provides for cleaning a pothole, filling it with a mixture of moistened mineral material of a selected composition and a liquid organic binder (tar or liquefied bitumen) and compacting 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 screenings of crushing═ PGS═ crushed slag. The mixture can be harvested for the future with the preparation in conventional asphalt plants, retrofitted with a system for supplying and dosing water.

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

6.1.33 Another method of "emergency repair" of potholes is the repair using cold asphalt (repair) mixes.

This type of repair is used for potholes up to 1 m2. Potholes are repaired immediately after they are discovered; in some cases, work can be performed without cutting the pothole or milling it.

The repair cold mix consists of a mineral filler, an organic binder with the introduction of special additives into it. The mixing of the mixture is carried out in forced action installations.

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

Thinners used to give the initial bitumen grade MG 130/200 a given viscosity (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 bituminous 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 desired properties.

The temperature of the mixture should not be below -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 repaired map.

When repairing potholes in the coating, depending on the depth of destruction, the repair mixture is laid in one or two layers with a thickness of not more than 5-6 cm with careful compaction of each layer.

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

It is not necessary to prime the repaired surface with bitumen or bitumen emulsion.

The repair mixture is laid taking into account the decrease in the layer thickness during compaction, for which the thickness of the applied layer should be 25-30% more 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, manual vibrating roller, mechanical, and for small amounts of work - with a manual rammer. With a pothole size exceeding 0.5 m, the mixture is compacted with a vibrating plate. The movement of the sealing means is directed from the edges of the section to the middle. The seal is considered complete if there is no trace of the sealing agent.

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

6.1.34 One of the pothole repair methods is to fill them with a poured asphalt concrete mixture. This mixture differs from the usual asphalt concrete mixture by the increased content of mineral powder (20-24%) and bitumen (9-10%) grade BND 40/60. The content of crushed stone is 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 place of work by special machines with a heated container and a prepared card is filled with it for repairing potholes.

After the mixture cools down to 50-60°C, traffic is opened along the repaired area.

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

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

6.2 Surface treatment device on pavement

6.2.1 The surface treatment device on the road surface improves its grip properties, as well as protection against wear and atmospheric factors. With the surface treatment device, 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, chipping, cracks and small potholes.

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

6.2.3 A single surface treatment device is produced in accordance with the Guidelines for the device of a single rough surface treatment using a technique with synchronous distribution of bitumen and crushed stone.

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

The sequence of the 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;

Selection of 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 service personnel of machines and mechanisms.

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

6.2.7 The choice 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 the approximate consumption rate of crushed stone and bitumen for a single surface treatment device


Fraction of crushed stone, 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 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 rates;

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

Compaction of the freshly laid rough layer;

Surface care.

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

Figure 6.2 - Synchronous distribution of binder and crushed stone with a surface treatment device

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. 5-6 passes of a self-propelled skating rink on pneumatic wheels are carried out along the surface with a wheel load of at least 1.5 tons and a tire pressure of 0.7-0.8 MPa, or a skating rink with rubberized metal rollers. The final formation of the layer occurs under the influence of passing road 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 up to 40 km/h;

Regulation of traffic across the entire width of the carriageway with the help of guide fences;

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

Reconsolidation with a roller.

6.2.13 With a single surface treatment device in a synchronous way, the time interval between bitumen pouring and crushed stone distribution 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 increased, both when using hot bitumen as a binder and bitumen emulsion.

6.2.14 Work on the device of 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 used as a binder bitumen should not be lower than +15°C, and when using a bitumen emulsion - not lower than +5°C. In some cases, if it is impossible to ensure the required purity 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 coating from dust and asphalt crumb residues;

Priming of the surface of the coating (if necessary);

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

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

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

6.2.16 Estimated costs of binder and crushed stone during their distribution 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 with a 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 filling of the binder is carried out on half of the roadway in one step without gaps and gaps. If it is possible to provide a detour, the binder is poured over the entire width of the carriageway.

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°С; for polymer-bitumen binders - 140160°C.

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

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

At air temperatures 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 can not be heated (at a bitumen concentration in the emulsion of 50%).

6.2.22 Immediately after the scattering of crushed stone, it is compacted with smooth-roller rollers weighing 6-8 tons (4-5 passes along one track). Then with heavy smooth-roller rollers weighing 10-12 tons (2-4 passes along one track). For a better manifestation of the rough structure, it is advisable to carry out the final stage of compaction with smooth-roller 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 the emulsion over the coating in the amount of 30% of the consumption;

Distribution of 70% of crushed stone from the total consumption (gap 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 rubble;

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

Surface care.

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

In the case of using an anionic emulsion, the movement 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 pavement surface

6.3.1 The device of thin protective layers of cast emulsion-mineral mixtures

6.3.1.1 Thin frictional wear-resistant protective layers of cast emulsion-mineral mixtures (LEMS) are used as frictional and waterproofing wear layers to increase the service life of road surfaces and improve traffic conditions. Wear layers are primarily needed 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 the top layer of asphalt concrete pavement;

2) laying LEMS on the milled asphalt concrete pavement.

6.3.1.3 Before laying a layer of LEMS, 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 laying of LEMS is carried out with 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 stone of igneous and metamorphic rocks with a strength of at least 1200. Sand fraction 0.1 (0.071) -5 mm consists of crushed sand or a mixture of natural and crushed sand in equal proportions. For a mineral powder (preferably activated) from carbonate rocks, it is assumed that the total amount 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 class, containing 50-55% bitumen. The compositions of LEMS are given in Table 6.3.

Table 6.3 - Compositions of cast emulsion-mineral mixtures


Mix type	Number of components, % by weight
	granite crushed stone, mm			mine- ral- ny pore- shock	portland- cement	water for pre- body wetting	bitumen emulsion (in terms of bitumen)
		crushed- ny	nature- ny
rubble





Sandy
		[email protected], we'll figure it out.

Environmental friendliness

Price

Practicality

Appearance

Ease of manufacture

Labor intensity when using

final grade

At the moment it is considered the most popular material used for paving. He is reliable enough. At the same time, asphalt markings with the best performance are intended for heavy loads, for example, such as M1200. A slightly lower density material (M1000) is no longer able to withstand the weight of numerous machines, so it is usually used only for laying paths and sidewalks.

Initially, it is necessary to mark the area on which asphalt is supposed to be laid. All work will depend on the purpose for which the coating is intended to be used. So, for an “easy” route, along which a large traffic flow is not expected, only one layer of crushed stone will be needed, but when building a highway, it will already be necessary to use at least three of its layers.

Fractions are stacked from largest to smallest and are very carefully rolled with a roller. At the first stage, it is necessary to form a special cushion on which the asphalt will be located.

If it is necessary that the coating be flush with the surrounding area, then you will first need to dig a foundation pit to the required depth, and after laying rubble in it, proceed directly to pouring the asphalt mass. All road works on laying asphalt are carried out in accordance with the requirements of SNIP and GOST.

There are two main ways to build asphalt roads:

Cold. Usually suitable for repairs, as it sets very quickly and it will soon be possible to use the coating to the fullest;
Hot. Applicable when laying a new road. In this case, the bituminous mixture must be rolled before it begins to cool.

The consumption of bitumen during the repair of the coating should be at least 0.5 liters. But the consumption of asphalt when laying a new route is calculated separately. Here it is necessary to take into account not only the size of the road, but also its structure, as well as other additional factors.

When working, be sure to use a special thermometer that allows you to determine the temperature of the building material. Constant monitoring of this indicator is important, since after cooling, the bitumen will no longer be suitable for laying a road.

On the video - the technology of laying cold asphalt:

Application of impregnation

At the moment, there are three types of impregnations that are part of the road surface:

Based on acrylic polymer. One of the expensive coatings, which is used only in limited areas. For example, such as tennis courts. They provide the highest quality protection, and are also available in several colors.
Coal tar. A modified coating that is able to resist the effects of petroleum products. Thanks to special components, not only long-term service is ensured, but also high-quality color.
asphalt emulsion. It is quite common and affordable, but does not provide adequate protection, which is why the canvas may soon require repair.

When cracks form on the laid asphalt, the bituminous mixture is no longer used as a fill. For this purpose, a sealant is used, which is then sprinkled with a fine crumb of cement. To prevent their occurrence and ensure the best strength allows the use of special grids for asphalt. With the help of them, a reliable coupling of the coating is made, and its service life is improved and extended.

Seal- This is a very important step in laying the coating. For this purpose, it is possible to use special paving machines: a roller, a vibrating plate or an asphalt paver. Each of these types of equipment is quite mobile, but has some advantages over other types of rolling. So, the vibrating plate has the best maneuverability, and the asphalt paver can carry out at least two types of work.

In the photo - the process of compaction of the coating when laying asphalt

Do-it-yourself asphalt laying

In private construction, using asphalt, blind areas are made, paths and sidewalks are arranged. In addition, asphalt can be used to form roofing and interior work.

When laying tracks on your own, the work is done in stages:

Initially, up to 30 cm of soil is removed and all debris is removed;
Next, curbs are installed, which will serve not only as an additional decoration, but also prevent the spread of bitumen;
At this stage, a pillow is created. The crushed stone layer should reach 15 cm, after rolling which you can pour a finer fraction of crushed stone and roll it again. Last layer there will be sand. It will be enough 5 cm. After creating such a pillow, you will need to fill it with water and roll it with a hand roller;
Hot asphalt must be evenly scattered around the entire perimeter of the track. Further, to level the bumps, it is necessary to use a mop-engine, gradually filling all the pits with new portions of asphalt. Since the material hardens quickly enough, several workers are needed to carry out all the work;
When the road section is filled with asphalt and leveled, it is necessary to compact it with a hand roller. You will first need to lubricate the roller with diesel fuel in order to prevent sticking and ensure uniform coverage. It is important to cover with diesel fuel all the tools that work is done.

The temperature of the asphalt during paving is very important. It should not fall below 120C, otherwise the coating will soon become completely unusable.

When laying, it is important to make only direct movements, reverse ones are strictly prohibited. Bitumen consumption in this case is calculated individually and can be either 5 or 10 kg. At the end of the work, instead of impregnation, you can use a special paint for asphalt. She will give the necessary shade. In addition, you can use white paint for marking asphalt.

How to lay (lay) asphalt with your own hands will tell the video:

Roadbed repair

After some time, the bitumen will need to be repaired. If it is carried out on time, replacing the most worn out areas, then it will last a much longer period. The most important part of the repair phase is milling. It involves the removal of the old coating with a cutter.

After that, surface texturing is carried out. The hot milling method involves first heating the asphalt pavement, but with the cold method, this is not considered mandatory. The latter is practically indistinguishable in quality from hot, but it is able to facilitate the work several times.

The seam cutter is also designed for removing the coating, as well as for cutting seams. For the transportation of asphalt mass, a coher is used, which is specially made for this purpose. It can be both mobile and stationary.

To minimize the use manual labor, in many cases, entire automated systems are used. For example, for road repair, asphalt stripping machines are widely used, which carry out milling and cutting of unsuitable pavement using a diamond blade.

Removing asphalt with a floor cutter

patching

The entire canvas is not always repaired. Most often, the pitting technique is used, the technology of which involves filling all potholes and cracks with bituminous mass. It can be used when the damage does not exceed 15% of the total number of defects.

Before proceeding with the repair, it will be necessary to carry out preparatory work:

Markup. In this case, it is necessary to mark not only the damaged area, but also a certain amount of the whole canvas. If several potholes are located in the same radius, then they must be painted with a common contour.
Next, the damaged asphalt layer is dismantled using, for example, a jackhammer. It is best to use the cold milling method, as it allows you to create even walls.
At this stage, debris and coating crumbs are removed, after which potholes can be treated with a special bitumen composition.

On the video - how asphalt is laid using the UYAR-01 patching machine:

Material evaluation

Having considered in the article the use of asphalt pavement and the most important aspects of its repair, we can characterize it as follows:

Bitumens used in modern laying of coatings are considered the most environmentally friendly, in comparison with similar material of past years;
Available to many segments of the population, but still quite expensive;
Let's apply to creation practically of all coverings. Additionally, it can be used in the construction of structures;
The coating put into operation has a fairly good appearance. Over time, bitumen can fade, but the color can be maintained with the help of special paints;
Impossible to make by yourself;
Requires fairly quick skill and the use of additional workers, as it can quickly cool down and become unusable.

The problem of patching, unfortunately, is faced by all road maintenance enterprises. The reason is that our roads are mostly old. Built in the last century according to the old requirements. And the intensity and load are growing exponentially. Simply replacing the top coat is not effective. Gain Required bearing capacity pavement, and this, in addition to the coating, is a crushed stone base, an underlying layer and even a replacement of heaving soil under the road body.

In addition to all this, drainage is necessary, water is the main enemy of the road. As my grandmother used to say, water is strong, it breaks even a mill. For example, your humble servant, having traveled on December 23 from Yuryevets to Globus along the federal road, managed to catch three “traps” with his wheels. Given the fact that the size of the rubber on my car is not the smallest, the impacts were quite sensitive. And what will happen to the usual subcompacts of the Zhiguli class?

Dear Feds colleagues! With your very considerable funding, it would be time to work with your head and take effective measures to eliminate the “traps”. Otherwise, you will not only receive curses, but also decent fines from the traffic police, and probably lawsuits from owners of crippled cars.

Do not forget, you exist on our very big money, which we pay in the form of taxes, excises and other fees.

While working in the Murmansk region, I also performed patching in winter time. We tried more than a dozen different methods and mixtures. I can say for sure: repairs with cold mixtures are ineffective, any patch lasts from a week to two months. Considering the technical characteristics of various mixtures, I came to the conclusion that poured asphalt concrete should be the most effective. I did not work with him, I may not know some features of working with him, but, consulting with my colleagues from other regions, I heard good reviews. And just recently, information was received about the acquisition by the City Roads Management Center of a new installation for patching. Although cast asphalt is not a novelty in the road industry, this is the first time I have encountered it. In the late nineties - early 2000s, St. Petersburg colleagues dissuaded me from purchasing such an installation because a large number worker burns. The mixture was supplied at a temperature of 260 - 280 degrees, when it came into contact with water, it boiled and steam was released with boiling bitumen. In St. Petersburg at that time, such installations were used only on tram tracks. But technologies are changing, and purely professional interest has already urged me on.

We drive out onto Verkhnyaya Dubrova street opposite house 43. Behind us comes a KAMAZ with an installation and a Sobol with a team of workers. Remains of limestone rubble are visible in the collapsed coating. Wasn't he the cause of the destruction of the coating?

Road workers quickly clean the dirt and snow from the pit with hard brooms, blow out the remains with a portable blower. Immediately from the bunker, the mixture is fed, which is manually leveled.

Compaction with a vibrating plate or roller is not carried out, the mixture is quite liquid, so self-compacting occurs. It is striking how the rest of the water boils away and leaves the freshly laid mixture with steam. Boiling and evaporation of water takes another 15 minutes, and no wonder - the temperature of the mixture at the outlet is over 200 degrees.

After the mixture cools, movement opens. How reliable the completed patch is, I can’t judge - time will tell. I'll try to keep an eye on her in the future. But as the workers say, the old coating is falling apart nearby, but the new patch is holding.

Outrageous rudeness of some drivers. The place of work can be seen from afar, but they fly at a wild speed, they go around the place of work with a dashing skid, as if there were no people working there. Self-respecting gentlemen, remember: road workers do very necessary work for everyone for not very high wages, they also have children and families who need to be fed. They do not wear uniforms and shoulder straps, they are not civil servants. Very often they are the only breadwinners in the family. If something happens to them, you will not only ruin your life, but also doom their families to poverty, because survivors' pensions are paid beggarly.

For example, quite recently in the Murmansk region, two road workers were shot down to death while clearing snow from reflectors on barrier fences. Eternal memory to them.

Dear leadership of the traffic police, a car with flashing lights reduces the speed by half, but you are doing a common thing - do not limit yourself to prescriptions and protocols, help road workers.

Molded asphalt concrete is a hot, laboratory-selected mixture of a special grade of bitumen, sand and crushed stone. The mixture is made at the asphalt plant, poured into the plant and sent to the work site. The patching plant is a thermal bunker with a volume of about 6 cubic meters, in which the mixture is continuously mixed and the set temperature is maintained using a burner.

The advantage of this technology is that the pit edges are not trimmed, which significantly increases productivity. The unit is mounted on the chassis of a KAMAZ vehicle. Once upon a time, there was a similar trailer installation at the enterprise, but it failed due to advanced age. The volume of the bunker was very small, it was enough for just a couple of hours of work, so the work efficiency was very low. The new equipment was bought quite recently at the expense of the municipal budget. The workers speak respectfully of Andrey Shokhin, the head of the city administration, who, in the most difficult times, finds money to upgrade equipment at the enterprise.

It's unusual for me to hear this. In my homeland, after the removal of our governor, the two who came after him did not provide any assistance to road repair enterprises at all, and then they were simply destroyed, sold under the hammer. And in the Vladimir region, both the regional and city administrations are still buying equipment. Naturally, this situation affects the well-being of the enterprise.

Control over the work performed is carried out by Dmitry Rebizov, Head of the Improvement Objects Service of the Central Directorate for Urban Development. He told us about the enterprise and its tasks.

The City Roads Control Center maintains all the streets of Vladimir. The total area of maintained roads is 3.8 million square meters. I don’t undertake to translate into kilometers because of the different widths of the roadway, but the figure will turn out to be decent. The company employs 450 people. Naturally, all roads are divided according to the timing of snow removal into primary and secondary. On the balance sheet of the enterprise there are 8 graders, 8 loaders, 14 tractors, 3 sidewalk gritters, 30 KDM, 8 paw loaders of snow and even 1 snow blower based on the MTZ tractor.

Almost all equipment operates in a two-shift mode, in case of urgent need it switches to a round-the-clock one. Only 35,000 cubic meters of sand is imported for road filling. Periodically, thanks to the efforts of the city administration, the equipment is updated. I am a new person in Vladimir, I am sure that there are still a lot of complaints about the enterprise and there will be, but it can be said unequivocally that its work is improving. For example, I can mention the maintenance of the Yuryevets - Mosino road. Over the past five years this winter, so far it has been of the highest quality.

I would suggest thinking about treating the central streets with high traffic intensity at air temperatures down to minus 10-12 degrees with pure salt, without sand.

What does it give? Save on sand and transport costs. How much sand (by the way, not best quality according to the granulometric composition and a rather considerable percentage of dust-like and clay particles) you will bring to the city, the same amount must be taken out mixed with snow. To this is added work until half of the summer on manual cleaning of sand residues.

Do not pour sand - drainage wells and pipes are not clogged, manual cleaning of gratings on drainage wells is practically not required. The streets and cars are becoming incomparably cleaner. At a sufficiently high air temperature, as in recent years, the number of snow removal cycles is reduced, and the equipment can be used on secondary streets for better and more timely cleaning. With small amounts of precipitation and mild frosts, salt-treated snow in the form of water simply flows off the road. Well, working with pure salt is a whole science, back to our pits.

The question arises: is it necessary to patch holes on the roads at all? The roads are mostly old. Over the next year or two, bringing them into a standard state with a decent margin of safety is an unrealistic and hardly feasible task. Therefore, whether you like it or not, it is necessary to maintain the existing road network in working order. Pothole repair is, of course, not a panacea. But which is better: driving without adventure or risking the condition of the car and your health? According to statistics, there are many accidents with serious consequences due to the substandard condition of roads in the country. Therefore, road builders must eliminate every hole and crack all year round, even more than once, in order to prevent their deepening and growth in size.