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
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 and the environment is placed in the crack at the bottom of the chamber. 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 plaster 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. Bituminous mastic is immediately fed into the cleaned, dried and heated cavity of the cut crack from the melting and pouring 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 filler, 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/h. 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 pavement of a dense fine-grained asphalt concrete mixture with 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 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 mix with 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 gun.
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 dedusting 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 when the area of the pothole is up to 1 m.
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 reduction 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 may be stored under a canopy in open stacks on a concrete floor for 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 warm summer 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
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 ice 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 the device of a single surface treatment in a synchronous way, the time interval between the pouring of bitumen and the distribution of 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 increased, both when using hot bitumen as a binder and bitumen emulsion.
6.2.14 Work on the double surface treatment device 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%. |
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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°C; 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 cast mineral-emulsion mixture (LEMS) friction wear layers are used as friction and waterproofing wear layers to increase service life. pavement and improving driving 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 |
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|
granite crushed stone, mm |
mine- |
portland- |
water for pre- |
bitumen emulsion (in terms of bitumen) |
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|
crushed- |
nature- |
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|
rubble |
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|
Sandy |
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|
[email protected], we'll figure it out. | ||||||||
gravel and gravel coverings. During their repair, periodic repair profiling is carried out, potholes, ruts and subsidence are eliminated, and dust removal measures are also taken. Repair profiling of the coating with the addition of new material is carried out by motor graders or graders at optimal moisture content (from 10 to 15%, depending on the composition of sandy-clay fractions), corresponding to such a state of gravel or crushed stone material, when it is well cut, moved and compacted (Table 12.4 .one).
Table 12.4.1
Repair profiling of gravel (crushed stone) pavements with the addition of new material (per 1000 m of pavement)
| Type of work | Coverage width, m | Number of circular passes | The composition of the link | Labor intensity, man-hour |
| Scarifying the pavement with a scarifier mounted on a motor grader | Machinist of the 5th category - 1 | 0,59 0,63 | ||
| Road worker of the 2nd category - 1 | ||||
| Motor grader moving additional gravel material from the shoulder, leveling across the entire width of the pavement | Machinist of the 5th category - 1 | 0,77 | ||
| 0,66 | ||||
| Motor grader mixing of boiled and newly added material with collection in a measuring shaft | Machinist of the 5th category - 1 | 0,51 | ||
| 0,44 | ||||
| Leveling and leveling of the material over the entire width of the coating | Machinist of the 5th category - 1 | 0,77 | ||
| 0,66 | ||||
| Watering the planned gravel material with water (norm up to 0.9 m 3 per 100 m 2) | 6-7 | - | Machinist of the 4th category - 1 | 0,75 |
| Compaction of the material with a self-propelled roller (8-10 tons) in 4 passes on one track | 6-7 | - | Machinist of the 5th category - 1 | 2,2 |
| Regulation of movement along the width of the pavement and maintenance of that pavement within 3 days with rearrangement of fences | 6-7 | - | Road worker of the 2nd category -1 | 1,38 |
To be repaired boil up. After removing the boiled material, the pothole is covered with gravel material, in composition close to the material of the top layer of the coating with grains no larger than 20 mm, 1 ... 2 cm above the coating level. Scoured material can be used to seal potholes, but only after it has been screened.
At large volume works, gravel material is compacted with self-propelled rollers on pneumatic tires or rollers weighing 5 ... 10 tons, and with a small amount of pneumatic, electric or manual rammers weighing 25 ... 30 kg. Seal from the edges to the middle of the potholes. For better compaction, the material is watered with water at the rate of 1.5 ... 2 l / m 2 for each centimeter of the depth of the pothole. Instead of water, it is advisable to use a 30% aqueous solution of calcium chloride CaCl 2 or a 30-40% aqueous solution of technical lignosulfonate.
Repair of potholes or subsidence of crushed stone pavement built by the wedge method is carried out by the same method, and pavements from a mixture of optimal composition - as well as gravel pavements (Tables 12.4.2 and 12.4.3).
Table 12.4.2
Cost of materials for repairs
Table 12.4.3
The composition of the link and labor costs
Ruts and small ridges formed under the influence of traffic are leveled with heavy rollers, after moistening the coating. This method is used to eliminate small irregularities on a fairly durable coating. In other cases, ruts are eliminated by patching.
Crushed stone and gravel coatings treated with organic binders. In the process of repair, potholes, damage and uneven edges, bumps and sagging, small breaks and subsidence of the coating are eliminated.
Patching is carried out mainly with cold crushed stone (gravel) mixtures treated with organic binders.
In some cases, it is allowed to use cold or hot asphalt concrete mixtures or the direct or reverse impregnation method. In cold mixes, liquid (or viscous) bitumen, coal tar, bitumen emulsions are used as a binder.
Repair is carried out: in a cold way, if the air temperature is not lower than 5 ° C and in a hot way, if the air temperature is not lower than 10 ° C.
The cold method is appropriate for potholes up to 3 cm deep, and the hot method for potholes deeper than 3 cm.
With any of the above methods, the repaired site is prepared, including trimming (scribing) the edges, cleaning from dust and dirt, treating the cleaned surface with an organic solvent (solar oil, kerosene) at a rate of 0.1 ... 0.15 l / m using spray guns or sprayers and applying liquid bitumen, residual bitumen (tar) with a viscosity of 20-70 or tar in the amount of 0.3 ... 0.5 l / m 3 heated to 60 ° C on it.
Immediately after priming, the pothole is filled with repair material, the layer thickness of which is determined taking into account the compaction coefficient.
When using hot mixes, the material is laid in one layer when the depth of the potholes does not exceed 5 cm, and in two layers if the depth is more than 5 cm, and carefully compacted in layers. If the impregnation method is used, crushed stone no larger than 0.8 of the depth of the pothole, but not smaller than 16 mm, is placed in the prepared pothole, and compacted. Then viscous bitumen or tar is poured at the rate of 0.8-1.0 l/m 2 for each centimeter of the depth of the pothole. The temperature of the binder during filling should be: bitumen grades BND 200/300, BND 130/200 - 120...160°C. Spilling binder, crushed stone of fraction 5...15 mm is distributed and compacted. Small repaired areas are compacted with rammers.
Plots of pavement damaged by numerous potholes are repaired with cards. Damaged sections of the edges of the pavement at the interface with the shoulders are corrected by the above methods of patching, ensuring proper support from the side of the curb.
Asphalt concrete pavement. The main work on the repair of asphalt concrete pavements include the restoration of worn upper layers, elimination of damage in the form of potholes, cracks, individual waves, bumps and sagging, breaks and uneven edges, surface treatment, protective layers and wear layers. These works are started in the spring with the onset of warm and stable weather. Repair work begins with patching potholes using patching methods using cold milling of the coating. Milling is carried out using cold milling machines. Technical characteristics of a number of cutters firm "Wirtgen" are given in table. 12.4.4.
Table 12.4.4
Technical characteristics of milling cutters "Wirtgen"
| Options | Mill brand | ||||
| W 350 | W 500 | W 600 D C | W 1000 F | W 1200 F | |
| Milling width | 350 mm | 500 mm | 600, 500, 400 mm | 1000 mm | |
| Milling depth | 0...100 mm | 0...160 mm | 0...300 mm | 0...315 mm | 0...315 mm |
| Engine power | 35 kW (48 hp) | 19 kW (107 hp) | 123 kW (167 hp) | 185 kW (252 hp) | 185 kW (252 hp) |
| Operating weight | 4400 daN (kg) | 7400 daN (kg) | 12030 daN (kg) | 17300 daN (kg) | 17300 daN (kg) |
| Milling drum drive | mechanical | hydraulic | mechanical | mechanical | mechanical |
| Number of wheels | 3 (optional equipment 4) | ||||
| ground drive | guide / front wheels | guide / front wheels | guide / front wheels | guide / front wheels | guide / front wheels |
When repairing, the general technological sequence is observed, which includes preparing the damaged area, preparing, laying and leveling the mixture, and compacting.
Hot and cold asphalt mixtures, poured asphalt, crushed stone and gravel materials treated with an organic binder serve as repair materials. Hot asphalt mixes and cast asphalt are mainly used on non-roads of categories I and II.
Repair of coatings using hot asphalt mixes is carried out in dry and warm seasons at an air temperature of at least 10°C. Molded asphalt can also be laid at low air temperatures - down to -5°C.
The preparation of the repaired site is carried out in the following order: the boundaries of the potholes are outlined in straight lines, capturing the undamaged part of the coating by 3-5 cm, several small potholes, closely spaced from each other, are combined into one common map; old asphalt concrete is removed along the outlined contour, the pothole is cleaned and (if necessary) dried; the bottom and its walls are primed with a bitumen emulsion with liquid or viscous bitumen heated to 60 ° C, at a rate of 0.3-0.5 l / m 2.
After the preparatory work, the pothole is filled with repair material, taking into account the safety factor for sealing. If the depth of potholes is up to 5 cm, the mixture is laid in one layer, more than 5 cm - in two layers.
Small potholes isolated from one another are compacted with electric or pneumatic rammers, manual vibratory rollers, and large areas are compacted with smooth-roller rollers weighing 4-10 tons. The best results are achieved when using rollers with rubber-coated rollers.
Compaction is carried out from the edges to the middle, while the surface of the repaired places after compaction should be at the level of the coating. Approximate indicators of work are given in table. 12.4.5.
Table 12.4.5
Labor costs and output during pavement repair
When filling potholes deeper than 5 cm, when not only the upper, but also the lower layer of asphalt concrete is removed, the work procedure does not change: a coarse-grained mixture is placed in the lower layer and compacted, then a fine-grained mixture is placed in the upper layer and compacted. If the pothole is up to 8 cm deep and there is no coarse-grained mixture, a medium-grained mixture is laid in two layers. Fine-grained or sandy mixture is used only for the top layer.
When using infrared burners, the pothole, having cleaned of dust and dirt, is heated to 140-170 ° C, the heated edges are scraped to a depth of 1-2 cm, the bottom of the pothole is loosened, and the boiled material is distributed along the bottom and the required amount of a new mixture is added, compacted (if it is not a cast mixture) to the required density. The amount of the added mixture is set according to the size and depth of the pothole, taking into account the settlement during compaction (Table 12.4.6).
Table 12.4.6
The need for a mixture
| Hollow depth, mm | The amount of the added mixture, kg with the area of the pothole, m 2 | ||||||||
| 0,1 | 0,2 | 0,3 | 0,4 | 0,5 | 0,6 | 0,7 | 0,8 | 0,9 | |
When sealing potholes that are dangerous for traffic, in early spring or autumn, when the coating is wet and the air temperature is above 0 ° C, it is recommended to use crushed stone materials treated with bitumen with surfactants. For the same purpose, the mineral material is treated with activators - lime or cement - 1.5 ... 2% by weight of the mineral material.
Influxes, waves and shifts on the coating are eliminated by patching or cut off with a motor grader knife (after they have been preheated) with subsequent surface treatment. For heating, self-propelled asphalt heaters with infrared burners (operating speed 0.5 ... 3.0 m / min) are suitable. Cracks in the coating are closed when they are open - in dry and warm weather, the temperature is not less than 5 ° C. Cracks with a width of 5 mm or more are sealed with mastic, and small ones are filled with bitumen and sprinkled with stone fines. Separate cracks with a width of more than 5 mm are sealed as follows: they are cleaned of dust and dirt with compressed air, a brush or metal hooks; moistened with an organic solvent (solar oil, kerosene) at a rate of 0.1 ... 0.15 l / m 2 using spray guns or spray guns with a small spray angle; poured bituminous mastic(Table 12.4.7). Cracks are filled with excess. After removing the excess mastic, the crack is sprinkled with hot stone cuttings or sand. Cracks with destroyed edges are cut by cutting or milling asphalt concrete with a strip of 10 ... 15 cm on each side for the entire thickness of the deformed layer. Cutting down the material can be replaced by heating with infrared burners.
| Road-climatic zone | Mixture number | Composition of the mixture, % by mass | |||
| bitumen grade BND 90/130 or BND 60/90 | mineral powder | rubber crumb | asbestos crumb | ||
| II | |||||
| II and III | - | ||||
| - | |||||
| III and IV | - | ||||
| - | |||||
| IV and V |
On coatings containing organic binders, including asphalt concrete, during repairs, a single or double surface treatment is arranged or a thin layer of asphalt concrete and similar mixtures is laid (Table 12.4.8). Prior to performing these works, the coating must be cleaned of dust and dirt, potholes eliminated and cracks repaired.
Table 12.4.8
Single surface treatment device on asphalt concrete and other black surfaces (per 1000 m 2 of coating)
| Type of work | The composition of the link | Labor intensity, man-hour |
| Cleaning the coating from dust and dirt in six passes of a mechanical brush | Machinist of the 4th category - 1 | 0,25 |
| Having solved bitumen with an asphalt distributor (norm 0.5 ... 1.1 l / m 2) | Machinist of the 5th category - 1 | 0,43-0,45 |
| Distribution of measured crushed stone by the T-224 distributor (norm 15 ... 30 kg / m 2) | Driver of the 5th category - 1, road workers of the 3rd category - 2 | 0,39 |
| Compaction (rolling) of black crushed stone with a light roller (5 ... 6 tons) in 5 ... 6 passes along one track | Machinist of the 5th category - 1 | 2,1 |
| Compaction of black crushed stone with a heavy pneumatic roller (10 ... 16 tons) in 5 ... 6 passes along one track | Machinist of the 5th category - 1 | 1,5 |
The repair of asphalt concrete pavements also includes work to restore the continuity and evenness of the upper layer using thermal profiling technology based on the principle of regeneration (restoration of lost properties).
Improving the adhesion properties of asphalt concrete and cement concrete pavements is carried out mainly by means of a double surface treatment device. The technology for performing work is described in Section 4.
For surface treatment on cement concrete pavements, it is advisable to use a rubber-bitumen binder: bitumen BND 60/90 or BND 90/130 from 85 to 91%; coal oil - 6...10%; crumb rubber - 3...5%.
Bituminous binder is prepared in boilers with a paddle mixer. First, dehydrated and heated to 150-160 ° C bitumen is loaded into the mixer in the amount of 10% of the required volume, then the calculated amount of dehydrated and heated to 40 ... 70 ° C coal oil and the mixture is thoroughly mixed for 10 ... 15 minutes . In the bitumen liquefied in this way, a predetermined amount of dried rubber crumb, sifted through a mesh with 3 mm holes, is added in small portions. The mixture is stirred for 1.0...1.5 h at a temperature of 150-160 °C. Then, without stopping mixing, the rest of the dehydrated and heated to 160 ° C bitumen is loaded. All components are finally mixed for 30 minutes at a temperature of 160 °C. Surface treatment device technology is described in section 4.
The scope of work on the arrangement of wear layers, as well as indicative indicators of work are given in table. 12.4.9
Table 12.4.9
Construction of a wear layer 1.5-3 cm thick from asphalt concrete and similar mixtures on black coatings (per 1000 m 2 of coating)
| Type of work | The composition of the link | Labor intensity, man-hours |
| Cleaning the coating from aching and dirt mechanical brush | Machinist of the 4th category - 1 | 0,25 |
| Priming of the coating with liquid bitumen distributed by an asphalt distributor (norm 0.5 l / m 2) | Machinist of the 5th category - 1 | 0,24 |
| Asphalt paver DS-181 | Machinist of the 6th category 1, asphalt concrete workers: 5th category - 1, 4th category - 1, 3rd category - 3, 2nd category - 1, 1st category - 1 | 21,6 (2,7) |
| Pre-compaction of the layer with light rollers in 5-8 passes on one track | Machinist of the 5th category - 1 | 5,2 |
| Compaction of the layer with heavy rollers on pneumatic tires in 10-12 passes along one track | Machinist of the 5th category - 1 | 7,6 |
Thermal profiling of asphalt concrete pavements. To restore the top layer of asphalt concrete pavements, technology based on the regeneration of pavements with the help of special machines is increasingly being used.
Regeneration is performed by various methods of thermal profiling, the main operations of which are: heating the coating; loosening (milling) it to a depth of 2-5 cm; loose mix planning; seal. Thermal profiling methods have varieties: thermal planning; thermohomogenization; thermal styling; thermal mixing; thermoplasticization.
Thermal planning method- the most simple, involves the implementation of only the basic operations indicated above. The average loosening depth of the repaired pavement depends on a number of factors, including the type of asphalt concrete and air temperature (Table 12.4.10).
Table 12.4.10
Average loosening depth
In the thermal planning mode, sandy asphalt concrete pavements are repaired with water saturation not exceeding 3% by volume (1.5% for areas with excessive moisture).
When repairing a pavement made of fine-grained asphalt concrete with a water saturation not exceeding 4% (3% for areas with excessive moisture), or sandy with a water saturation of more than 3% (up to 4% inclusive), thermal planning is combined with surface treatment or a wear mat. In this case, correction of the transverse slope is achieved. coverage up to 4%.
In other cases, after thermal planning, a protective layer of a new asphalt concrete mixture is laid on the pavement. It is most efficient to carry out this operation in one thread with thermal planning. The paver moves 15-20m or thermal profiler. Due to the fact that the final compaction of the old and new mixtures is carried out in one layer, its density increases. In addition, the thickness of the protective layer of the new mixture can be reduced to 1-2 cm versus 3 cm in the traditional way. This mode is a variation of the heat styling method.
Thermohomogenization method differs from thermal planning in that, in addition to the main operations, it also provides for the regeneration of asphalt concrete by mixing the old asphalt concrete mixture. This increases the homogeneity of asphalt concrete and improves the compaction of the layer, which makes it possible to somewhat expand the scope of this method compared to the previous one.
Coatings with water saturation not exceeding 4% are repaired by the thermohomogenization method. Thermohomogenization is carried out using thermal profilers equipped with a stirrer in the form of one machine or a set of machines.
heat laying method, in addition to the basic operations, it provides for the addition of a new mixture in the form of an independent layer over the loosened old mixture.
This method, unlike the previous ones, has a wider scope, since it allows repairing pavements with large amplitudes of irregularities, deeper ruts, significant pitting, unsatisfactory transverse slopes and higher water saturation. In addition, this method is effective when, for some reason, the coating cannot be loosened to a depth equal to or greater than the minimum allowable.
Heat laying can be used to repair coatings with water saturation up to 6%. The amount of added new mixture depends on the evenness of the repaired coating, the degree of its wear and is usually assigned within 25...50 kg/m 2 . If it is necessary to correct the transverse slope of the pavement by more than 4%, the consumption of the added asphalt concrete mixture is increased (Table 12.4.11).
Table 12.4.11
Increasing the consumption of the added mixture
The advantage of the heat laying method is the possibility of simultaneous compaction of the old and new mixture in one layer, which increases its density. Thermal laying is carried out using a thermal profiler equipped with equipment for receiving and distributing a new mixture in the form of a single machine or a set of machines. You can also use an equipment kit that includes a paver to add new mix.
thermal mixing method unlike thermal laying, it involves mixing the new added mixture with the old one and laying the resulting mixture in one layer.
Its advantage is the possibility of correcting to a certain extent the composition of the old mixture and its regeneration. When performing work in this way, no requirements are imposed on the old coating that limit its water saturation. The flow rate of the added mixture is set depending on the evenness of the repaired pavement, the degree of its wear and the desired change in the properties of the old asphalt concrete. Thermal mixing is carried out using a thermal profiler, equipped, in addition to the equipment for thermal laying, also with a stirrer.
Thermoplasticization method differs from the previous ones by adding a plasticizer to the old mixture in an amount of 0.1-0.6% by weight of the latter. This operation must be accompanied by mixing. The method has all the advantages of thermoplanning and thermohomogenization, since it does not require the addition of a new mixture. In addition, it allows you to regenerate old asphalt concrete, expands the scope of this method, extending it to pavements with water saturation exceeding 3%. (The only limitation on the applicability of the thermoplasticization method is the presence of large irregularities on the coating and heavy wear, requiring the addition of a mixture. Thermoplasticization is carried out by the same machines as thermohomogenization, provided that they are equipped with a plasticizer injection unit. It is advisable to use oils of petroleum origin containing aromatic hydrocarbons as a plasticizer not less than 25% by weight.The most accessible renobit is a plasticizer proposed by GiprodorNII.It is also possible to use extracts of selective purification of oil fractions of oil, motor oil.Indicators of the physical properties of plasticizers must meet the requirements:
Kinematic viscosity at 50°С, m2/s........(25...70) 10 6
Flash point in an open crucible, °С, not less....100
Mechanical impurities, % mass fraction, not more than... 2.0
Water, % mass fraction, no more...................4,0
Fuel, % mass fraction, no more.............6,0
The plasticizer consumption depending on the depth of loosening of the coating and the speed of the thermal mixer is given in Table. 12.4.12.
Table 12.4.12
Plasticizer consumption rates, l/min
| Loosening depth, cm | Dosage of plasticizer, % by weight of asphalt concrete mix | |||||||||||
| 0,3 | 0,5 | 0,7 | ||||||||||
| Machine speed, m/min | ||||||||||||
| 1,5 | 2,0 | 2,5 | 3,0 | 1,5 | 2,0 | 2,5 | 3,0 | 1,5 | 2,0 | 2,5 | 3,0 | |
| 0,8 | 1,1 | 1,3 | 1,5 | 1,3 | 1,8 | 2,2 | 2,5 | 2,3 | 2,6 | 3,0 | 3,5 | |
| 1,2 | 1,5 | 2,0 | 2,3 | 2,0 | 2,5 | 3,3 | 3,8 | 2,8 | 3,5 | 4,7 | 5,4 | |
| 1,6 | 2,0 | 2,6 | 3,1 | 2,7 | 3,3 | 4,3 | 5,2 | 3,7 | 4,7 | 6,1 | 7,2 | |
| 2,0 | 2,6 | 3,3 | 3,8 | 3,3 | 4,3 | 5,5 | 6,3 | 4,6 | 6,1 | 7,7 | 8,9 |
Thermal profiling without the use of an additional asphalt heater for all methods (except for the third one with a consumption of a new mixture of more than 25 kg/m3) is carried out at an air temperature of at least 15 °C; in the third method, at a flow rate of a new mixture of 25 ... 50 kg / m 2, work is carried out at an air temperature of 10 ° C and above, and at a flow rate of more than 50 kg / m 2 - 5 ° C and above.
With the use of an additional asphalt heater, work by all means can be performed when the air temperature is not lower than 5 °C.
Thermal profiling works are carried out at a wind speed of not more than 7 m/s. The temperature on the surface of the heated asphalt concrete pavement should not exceed - 180°C during the first and third methods of thermal profiling (the consumption of a new mixture is less than 25 kg/m2).
The temperature of the mixture in front of the tamper bar in all thermal profiling methods (except the fifth one) should not be lower than 100°С, in the fifth method - not lower than 85 °С.
The specialists of the Ministry of Construction of Ukraine have established the following duration of heating of the layer of asphalt and tar concrete coating to an average temperature of 110 and 80°C, respectively (Table 12.4.13).
Table 12.4.13
Coating heating time
Note.In the numerator- heating time of asphalt concrete to an acceptable temperature of 200°C, and the denominator - tar concrete to an acceptable temperature of 125°C.
Estimated resource requirement for various ways repair of asphalt concrete pavements (per 1000 m) is given in Table. 12.4.14.
Table 12.4.14
Resource requirement
Repairwithusing cast asphalt and cold organo-mineral mixtures. AT In accordance with the provisions of the current regulatory documents, repairs using poured asphalt type V can be carried out almost throughout the year (at temperatures down to -10 °C) [54].
Preparatory work is carried out in accordance with established requirements. In winter, the preparatory work includes cleaning the repaired maps from sand and salt deposits, snow, ice, and removing water.
Transportation of the mixture to the place of work is carried out in special self-propelled units with a thermos boiler or bunker, equipped with heating and a mixer. During transportation, continuous mixing and a temperature of the mixture of 180-240 ° C should be ensured, and, if necessary, batch unloading with varying the speed of the mixture.
Before loading, the thermos boiler (bunker) is heated for 10 minutes by two heaters or a nozzle to 180-190°C. The lid of the feed opening must be opened no earlier than 5 minutes before loading the boiler with the mixture.
It is forbidden to turn on the agitator drive clutch before starting the engine, as well as the agitator drive until the hopper is warmed up and if there are residues of a hardened (non-heated) mixture in it that prevents the movement of the agitator blades. During transportation, the total mixing time of the mixture in a mobile unit should be at least 20 minutes.
Arriving at the place of laying, the self-propelled unit is installed in front of the prepared pit in such a way that the outlet tray, when the boiler (bunker) is tilted, is directed directly into the pit. The mixture is unloaded when the outlet chute is tilted with simultaneous operation of the paddle mixer in the boiler. Works on the distribution of the mixture with distribution to the edges of the map and removal of excess, as well as smoothing and grouting of the junctions, are performed manually.
A separate operation is the distribution of black (or untreated) crushed stone over the surface of a freshly laid cast mixture to ensure the required adhesion properties in the repaired areas.
Crushed stone with a size of 3-5 (8) or 5-8 (10) mm is delivered to the place of repair work by dump trucks in the amount necessary for uninterrupted operation. The scattering of crushed stone is carried out in a uniform layer into one crushed stone immediately after the distribution of the mixture. The approximate consumption of crushed stone for a mixture of type I is 5 ... 8 kg / m 2. After the coating has cooled down to a temperature of 80-100 ° C, it is allowed to roll the distributed crushed stone with a hand roller weighing 30-50 kg. After the laid layer has cooled to the outside temperature, the unburned gravel should be swept away.
The movement of road transport on the finished coating opens when the coating reaches the outside temperature, but not earlier than 3 hours after the completion of the work.
With small volumes of repair with cards up to 3 m 2 (most often emergency), it is advisable to use cold organo-mineral mixtures. In the construction season, at an air temperature above 5 ° C, a mixture of grade I is used for repairs, in winter - grade II. Unlike the previously described repair methods with small cards, in this case it is allowed to lay the mixture even in rainy weather [54]. As with repairs using poured asphalt, there is no need to treat the prepared maps with bituminous materials. The need for special compaction of the laid organic-mineral mixture is also excluded.
The mixture is distributed into the prepared card manually with a compaction safety factor of 1.25-1.30. After distribution, it is enough to roll the mixture with the wheel of any car, including cars, in one pass along one track. It is possible to use vibrating plates for this purpose.
Traffic on the repaired area can be opened immediately after rolling. The final formation of the organo-mineral mixture layer occurs during the operation of the road surface under the influence of a traffic load.
Repair of coatings using organo-mineral mixtures in the areas of acceleration and deceleration of vehicles (crossroads, public transport stops) due to the peculiarities of the formation of the layer can only be a temporary measure, for example, emergency repairs in rainy or winter periods. A longer service life of such cards (directly proportional to the intensity of vehicle traffic) is noted in the haul sections.
Abroad, during current repairs using such materials, it is allowed to lay them directly into potholes (without preparing maps) with a minimum depth equal to the size of coarse aggregate.
Based on the results of a survey of repaired sections at federal road network facilities, it was found that the optimal layer thickness in a dense body should be considered to be at least two diameters of coarse aggregate.
The main condition for the correct assignment of the repair method is to determine the cause of the crack formation, the degree of destruction of the base and coating materials, the reasonable timing of the repair work and the economic feasibility of the cost of repair work.
Planned work on sealing temperature cracks should be carried out during periods of their maximum opening. The most optimal periods are spring with the onset of dry and warm weather or late autumn, when night frosts cause compression of the asphalt concrete of the road surface, but during the day it is relatively warm (not lower than 5...10 °C).
When sealing cracks, in addition to their sealing, a “soft hinge” should be created from the repair material between the layers of asphalt concrete separated in the horizontal plane. Therefore, in the warm season, when the cracks are opened to a smaller width, it is recommended to additionally cut them with the formation of a deformation chamber (reservoir).
Table 12.4.15
Parameters of deformation chambers
Calculation of the chamber width can be performed using a simplified formula
AT= 100 b · To one · T/l , (12.4.1)
where b- distance between cracks, established during visual examination of the coating, mm;
To 1 - coefficient of linear thermal expansion of asphalt concrete, taken depending on the brand and type of asphalt concrete, the type of stone materials and binders used, degrees (approximately 2.1 ´10 ° for asphalt concrete types "A" and "B"; 3.3 ´10 ° - asphalt concrete type "B" and "G");
T- the difference between the air temperature during the period of work and the minimum possible temperature in the winter, ° С;
l- limit relative elongation of the repair material at the minimum air temperature, % (according to the relevant regulatory documents, less than 50%).
In case of destruction of the edges of thermal cracks, the width of the chamber is taken not less than the width of the destruction.
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Rassvet LLC performs all types of repairs asphalt pavement and offers competitive prices. We carry out restoration road works in Moscow and the Moscow region.
The company accepts orders both for the implementation of complex work with preliminary diagnostics, and for road patching. The technology is selected depending on the degree of wear of the roadway, traffic flow and the availability of detours, terms.
| No. pp | Name of works | Unit rev. | price, rub. |
| 1. | The layout of the territory under the mark with compaction with a vibrating roller. | m 2 | 80 |
| 2. | Selection of an earthen trough with subsequent removal by dump trucks to a landfill. | m 3 | 450 |
| 3. | Milling of an existing asphalt concrete pavement 5 cm thick. | m 2 | 80 |
| 4. | Cutting asphalt with a diamond blade. | m.p. | 80 |
| 5. | Foundation made of sand 15 cm thick. | m 2 | 180 |
| 6. | The device of the base from crushed stone 15 cm thick. | m 2 | 350 |
| 7. | The device of the basis from an asphalt crumb of thicknesses. 15 cm. | m 2 | 150 |
| 8. | The device of the base from a cement-sand mixture of thicknesses. 3-4 cm. | m 2 | 120 |
| 9. | The device of the base from the reinforced concrete of thicknesses. 15 cm. | m 2 | 900 |
| 10. | Laying of asphalt concrete pavement from a sandy mixture of thicknesses. 4-5 cm. | m 2 | 400 |
| 11. | Laying of asphalt concrete pavement from a fine-grained mixture of thicknesses. 4-5 cm. | m 2 | 420 |
| 12. | Laying of asphalt concrete pavement from a coarse-grained mixture of thicknesses. 4-5 cm. | m 2 | 450 |
| 13. | Treatment of the base with bituminous emulsion. | m 2 | 20 |
| 14. | Pothole repair of asphalt pavement 4-6 cm thick. | m 2 | 650 |
| 15. | Dismantling of side stone with removal and disposal | m.p. | 150 |
| 16. | Installation of road side stone 100/30/15 on a concrete base | m.p. | 700 |
| 17. | Installing a garden side stone on a concrete base | m.p. | 500 |
With a large amount of work, the repair process is divided into several stages:
- preparatory work, including the delivery of building materials and the choice of equipment;
- installation of fences and organization of detours;
- patching of asphalt pavement;
- distribution and leveling of the leveling layer with subsequent compaction.
Depending on the condition of the roadway, the list of works may be adjusted.
Asphalt patching - an affordable way to level the road
Sealing of road cracks and potholes is the minimum amount of repair work. Pothole repair of asphalt pavement can be one of the stages of road restoration, but in case of episodic destruction it is used without laying the upper wear layer to reduce the cost.
Defects are filled with hot or cold asphalt mix. It is convenient to use the hot composition during the subsequent application of the wear layer, since there is no need to observe a break between these operations. Pothole repair of roads with cold mix is most often carried out without laying an additional coating, since for this it is necessary to pause for 10 days. The cold composition is applied without subsequent compaction, it occurs during the further operation of the road. This method of restoration is characterized by a low price.
We do road leveling. It can be produced mechanically using special equipment equipped with a cutter. In case of significant unevenness, laying a leveling coating is required. Depending on the size of the recesses, fine-grained or coarse-grained mixtures are used for asphalt repair.
Rassvet LLC provides quality control of the materials used in the repair work and strictly adheres to the necessary temperature regime. We have a diverse selection of special equipment for the application of any technology.
Benefits of overhaul and patching services from Rassvet LLC
The list of works includes various types of road restoration. We provide a full range of road repair services in Moscow and Moscow Region.
- Preliminary diagnostics is possible to determine volumes and terms.
- Work is carried out according to the plan, which, if necessary, is adjusted.
- Taking into account all the conditions, the optimal technology for leveling the canvas, the asphalt mixture, is selected.
- Pothole or full-scale repair is carried out qualitatively, in accordance with the price.
- All stages of the process are carefully controlled.
S. Dorokhin
The road, like any engineering structure, is designed for a certain service life, during which it is exposed to the effects of transport and weather and climatic factors. The most unprotected element of the road is the asphalt concrete pavement.
Due to loads and overloads, pavement materials wear out and age. Wear and tear occurs for other reasons, for example, due to the initial low quality of materials, low-tech performance of road construction operations. A common technological error is insufficient compaction of the roadway, which results in irregularities, deformations, peeling, chipping, cracks, chips, potholes, pits over time.
Practice has established that annually the local Maintenance coverage is required for 2...3% of the total road area. When serious damages and defects reach 12...15%, it is generally accepted to repair all 100% of this area. The systematic “treatment” of the road surface is carried out by various methods, means and materials, which together determine the quality, service life and cost, i.e., the effectiveness of repair work, the main goal of which is to ensure the safe movement of vehicles on the road at the speed allowed by the Rules of the Road.
In Russia, road surface repairs are most often carried out with the onset of stable warm, not lower than +5 ° C, and dry weather, although the need for urgent unscheduled or emergency repairs occurs almost at any time of the year and under any weather conditions.
In the April issue of the magazine, it was about grouting as the first measure to prevent further destruction. Today we will talk about the elimination of road pits, potholes and chips, in other words, about patching.
The choice of technological method of patching must meet certain requirements or criteria. The sealing of the defect must be of high quality and correspond to the required indicators of density, strength, evenness and roughness of the main part of the coating. The repaired area as a result of properly carried out work will last a long time. To comply with the technological process of pavement repair, the presence or availability of the required materials, machines and installations is necessary. Depending on the weather conditions, a simple or complex repair method is chosen, but in any case, it must meet the efficiency criteria for the timely opening of traffic. And, of course, repairs should be low-cost.
In Russia, asphalt concrete is laid on most of the roads with an improved type of pavement (95 ... 96%), so the main amount and the greatest variety of repair materials, machines, technologies and new developments relate specifically to asphalt concrete pavements.
The most affordable and common method of their repair is patching with hot mix asphalt, since the road services have a wide network of asphalt production plants and all the traditional raw materials (crushed stone, sand, mineral powder, bitumen) necessary for the preparation of the mixture.
When using hot technology, the quality of the paving is very high, but this method of repair depends on weather conditions and the accuracy of the technology, including a strict temperature regime. To a lesser extent, this effect affects the use of cold bituminous mixtures and materials based on liquid or liquefied bitumen and bitumen emulsions.
Russian road builders are slowly adopting alternative materials, especially those based on bituminous emulsions, although this group of technological repair methods is popular in many countries due to its simplicity and less stringent rules and requirements for weather conditions, high economy and a longer season for using such a coating.
When choosing between hot and cold technologies for repairing asphalt concrete pavements, it should be taken into account that the strength and water resistance of cold asphalt concrete prepared on liquid or liquefied bitumen are 2 ... 3 times lower than hot ones, and for this reason it is used mainly for and repair of road surfaces of III...IV categories. Hot asphalt mixes and cast asphalt are mainly used in the repair of roads of I...II categories.
The third group includes repairs using non-traditional and little common in the road industry mixtures based on bitumen, polymer, polymer bitumen, cement and other binders. special materials. They are used only in special cases, for example, during emergency repairs, sealing defects on cement concrete pavements, on bridge pavements, etc. The choice of a method for patching road pavements and bridge structures is the right and obligation of the customer and contractor. At the same time, the requirements, recommendations and results of new developments and practical experience should not be ignored, especially when preparing a defective place for repair. Properly performed preparatory work contributes to high-quality patching, which means compliance with the requirements of GOST R 50597–93 and guarantees the full operation of the road surface for 3 ... 4 years or more (in some countries, patching is guaranteed for 5 years).
Preparation of the repaired coating site includes several operations:
1. marking the boundaries of repairing potholes with straight lines along and across the axis of the road with the capture of an undestroyed pavement layer of 3 ... 5 cm, while several closely spaced potholes are combined with one contour or map;
2. breaking and removing the cut material of the coating with a jackhammer with an appropriate tip. A hydraulic type jackhammer weighing usually 16 ... 20 kg is connected either to a special small-sized portable hydraulic station with an internal combustion engine (ICE) or to a hydraulic drive involved in the repair process of a self-propelled cold cutter, self-propelled vibratory roller or other machine.
In some cases, for such work, it is possible to use a pneumatic jackhammer with a power of 0.8 ... 1.0 kW with its connection to a compressor with an air flow rate of at least 0.5 m 3 / min and a pressure of at least 6 ... 7 atm;
3. preparation for the repair of narrow and long potholes with an area of more than 2 ... 3 m 2 or cracks with destroyed edges, for which it is advisable to use cold milling cutters, as well as cutting, cutting or cold milling of the material of the repaired coating site along the outlined contour to the entire depth of the pothole, but not less than the thickness of the coating layer, while the side walls must be vertical. There are different types of cold cutters: small-sized and compact self-propelled, trailed or mounted, cutting off defective coating material with a width of 200...500 mm to a depth of 50...150 mm. Typically, in an hour of continuous operation, the cutter can travel 2300 m of linear length. On large areas of the destroyed coating, it is possible to use larger cold cutters with a larger width of cut material (500...1000 mm) and a maximum depth of up to 200...250 mm. Some models of cold cutters are additionally equipped with a belt conveyor that feeds the cut material into the front loader bucket or body vehicle‚ which significantly reduces the amount of manual work;
4. cleaning the bottom and walls of the repair site from small pieces, crumbs, dust, dirt and moisture, for which auxiliary Johnston vacuum cleaner or brush machines are mainly used;
5. treatment of the bottom and walls with a thin layer of liquid (hot) or liquefied bitumen or bitumen-containing emulsion. Processing or priming of the bottom and walls of a contoured pothole, cleaned of small pieces and dust, with a thin layer of liquid bitumen or bitumen emulsion (bitumen consumption 0.3 ... 0.5 l / m 2) can be performed using the means that are in available (mobile bitumen heater, bitumen boiler, asphalt distributor, road repairer, etc.). At the same time, it should be borne in mind that excessive lubrication with bitumen, as well as insufficient, reduces the quality of adhesion of the new coating layer to the old one. Very effective for lubricating a pothole are small-sized installations (5 hp) that pump bitumen emulsion into the spray nozzle of a hand-held fishing rod with a hose 3 ... ICE pump. For small jobs and small sizes Potholes can be primed with emulsion from portable containers (10 ... 20 l) with spraying with compressed air according to the principle of a spray gun.
As mentioned above, for repairs it is better to use hot mix asphalt with an asphalt concrete plant, where it will be prepared with high quality and at the lowest cost. It is advisable to deliver the mixture with asphalt concrete to the place of repair by a vehicle equipped with a special thermos bunker that keeps the mixture hot for several hours. In some countries (Germany, Holland, Sweden, etc.), regulatory documents legitimize the mandatory use of heat-insulated containers (thermos bins) for the repair of road surfaces, since the laid mixture with a temperature below 110 ... 120 ° C is considered a marriage.
Usually, foreign-made thermal containers, depending on the standard size and needs, contain from 2...2‚5 to 8...10 tons of hot mixture (volume 1.5...6 m the account of small heating‚ during the whole working day. An example of such the most advanced domestic means of delivering a hot mixture with an efficient thermos bunker with a capacity of 4 m 3 (enough to seal about 80 ...
Machine for repairing roads with hot mix ED-105.1 is designed for mechanization of patching of roads with asphalt concrete and bitumen-mineral mixtures (elimination of patching, repair with cards) at environment not lower than +4 °C and in the absence of snow cover. The repair complex includes: a cabin for service personnel, a cabin for technological equipment, thermos bunker for asphalt concrete, bitumen boiler, compressor, equipment for obtaining a hot air jet (“Hot Dog” - licensed production), vibrating plate VS-134 (option), trimmer CS-146 (option), airbrush, pneumatic drill, chipper a hammer. The drive of the hydraulic pump and compressor is carried out from the car engine through the power take-off. To move the material inside the hopper, augers are used, driven through a gearbox. Issuance of heated bitumen is carried out by a bitumen pump.
Previously, there were no such specialized vehicles in Russia. This repairer is equipped with all the necessary materials, tools and fixtures (hot mix, bitumen for priming, hydraulic hammer, vibrating plate, etc.). Unfortunately, the bunkers of Russian sand spreaders often used to transport the mixture cannot ensure the preservation of the heat of the mixture, especially in early cold spring or wet late autumn, which significantly reduces the quality and reduces the service life of pothole filling.
In those cases when the asphalt concrete plant does not work (late autumn, winter and early spring) or if the distance of transportation of the mixture with asphalt concrete is too long, it is recommended to use the recycling technology - secondary processing of asphalt concrete material in the form of pieces, scrap or milling products (crumb) by heating it and thorough mixing at the repair site in a special trailed or self-propelled machine - a recycler. Mixing of loaded materials takes place in a gravitational way in a cylindrical drum equipped with blades and a special burner. The mass of one batch (capacity of the mixing drum), depending on the type and size of the recycler, ranges from 200 to 1600 kg. The preparation time for one batch after loading the material and heating the drum to the required temperature is 10 ... 20 minutes.
The recycler works most efficiently if it is loaded with fine asphalt concrete chips obtained by cold milling. To improve the properties of the mixture when loading crumbs or lumpy scrap, it is recommended to add solid or semi-solid bitumen in an amount of 1 ... 2% by weight. Portion or complete unloading of the hot mix from the recycler is carried out directly to the place being repaired or into a small-sized hand truck or loader bucket to supply the mix to the place of laying.
The economic efficiency and feasibility of using recycling technology is very high. In the presence of asphalt concrete chips or lumpy scrap at the site of patching potholes, the cost of patching can be reduced by 50...60% compared to the delivery of a new mix from an asphalt plant, but recyclers have not yet taken root in Russia.
Jet-injection cold technology for sealing potholes on road surfaces using bitumen emulsion is now one of the most advanced and progressive, despite the fact that in some European countries and in America it has been used for a long time and successfully. The essence of technology is that everything necessary operations perform the working body of one machine (installation) of a self-propelled or trailed type.
Preparation of a pothole for repair actually comes down to its thorough cleaning of dust, debris and moisture by blowing with a high-speed air jet, washing and treating the surface of the pothole with a bitumen emulsion. Cutting, breaking or milling of asphalt concrete around a pothole can be omitted in this technology.
When filling a pothole, it is filled with fine gravel mixed with a bituminous emulsion. Due to the involvement and supply of crushed stone with an air jet, its laying in a pothole occurs at a high speed, which ensures good compaction, practically eliminating the need for additional use of vibratory plates and vibratory rollers. Such units and machines provide for the exit of the repairman-machinist from the cab of the vehicle to perform patching at the rear of the car or trailer.
For patching according to the jet-injection cold technology, it is recommended to use pure fine crushed stone of a fraction of 5 ... 10 (15) mm and a rapidly decomposing cationic (for acidic rocks, such as granite) or anionic (for basic rocks, such as limestone) bitumen emulsion 60% concentration. The consumption of emulsion for priming potholes and processing crushed stone in the mixing chamber of the machine can approximately be 3 ... 5% by weight of crushed stone (according to bitumen consumption - no more than 2 ... 3%).
The unit can be permanently mounted on a trailer or on a MAZ, KamAZ chassis. The new model ED-205M, offered by CJSC Kominvest-AKMT, will also become the main machine for patching by the method of pneumatic spraying for Russian road workers. The machine includes:
- base chassis, KAMAZ-55111, MAZ-533603-240, trailer;
- two-section bunker for two fractions of crushed stone: 5 ... 10 mm - 2.4 m 3, 10 ... 15 mm - 2.4 m 3;
- heated and insulated 1300 l emulsion tank with emulsion level control in the tank;
- water tank for 1000 l;
- blower for pneumatic supply of crushed stone of high productivity (from 13 to 24 m 3 / min);
- two augers for supplying crushed stone from the compartments of the bunker to the pipeline with adjustable speed of rotation of hydraulic motors;
- two diaphragm pumps for supplying emulsion and water with adjustable pressure;
- economical air-cooled diesel engine with a power of 38 kW (HATZ or Deutz) with smooth speed control from the operator's console;
- a set of equipment with a gas burner for heating the emulsion. At the request of the customer, it is possible to install an autonomous diesel burner;
- compressor with flow rate of 510 l/min and pressure up to 12 atm;
- two pressure regulators with manometers for water and emulsion;
- lightweight boom with pneumatic lift for work within a radius of up to 8 m;
- control panel that allows one operator to control the technological process of pavement repair;
- a circular circulation system that prevents the emulsion from solidifying in pipelines at low temperatures;
- a system that allows flushing and blowing pipelines of emulsion residues, pumping the emulsion into the tank using its own diaphragm pump, washing the bottom of the pit with water from clay and dirt under pressure up to 8 atm, moistening and washing crushed stone before feeding it into the pipeline to improve adhesion;
- crushed stone supply pipeline with a diameter of 75 mm and a length of 4.5 m, wear-resistant, seven-layer, with two strands of steel cord;
- removable nozzle with separate supply of water and emulsion.
In conclusion, it is worth mentioning a few "buts" that can be described as the causes of the second Russian problem - bad roads. When carrying out repair work in rain and snow, when it is difficult or impossible to clean the pothole from moisture, dust and debris, the technology is violated, and therefore the service life of the repaired area is reduced - it rarely exceeds a couple of months.
It is necessary to separate methods and means of mechanization of repair depending on the stage of destruction and classification of roads. We must try to carry out repairs in the early stages, when only cracks appear. Contracting organizations should not be allowed to repair, which, exploiting cheap illegal and, as a result, unprofessional workforce, carry out repairs using artisanal methods: they transport hot asphalt mix by dump trucks and compactors, and distribute, level and compact it manually with shovels and rakes. Such patches look like "clumsy blotches" and do not last long.
Pothole repairs of roads must be carried out in accordance with the local cost estimate, the terms of the draft contract and the work schedule agreed with the customer when concluding the contract. Perform work with high quality, in accordance with SNiP 2.05.02.-85. p.7.7-7.19. SNiP 3.06.03.-85 p.1-8 "Roads", SNiP 2.07.01-89. p.6.17-6.32. "Urban planning. Planning and development of urban and rural settlements”, GOST R 52289-2004, “Technical means of organizing traffic. Rules of application”, GOST R 50597-93 .p.1-5.3, “Roads and streets Requirements for the operational state, permissible under the terms of ensuring road safety”.
When patching roads, it is not allowed to use waste asphalt concrete and materials produced with their use, including milled asphalt.
Waste generated as a result of cold milling of asphalt concrete during the repair of road surfaces, at the request of the Customer, must be returned as the property of the city. The Contractor undertakes to deliver the milled material to the object indicated by the Customer.
Carry out patching of roads in accordance with the schedule, presenting the results of repairs around the clock (as agreed with the Customer).
The Contractor ensures the proper sanitary condition of the work area and is responsible for the improper condition of the area.
The customer reserves the right to determine the address priority of patching of roads, as well as address bindings.
The Contractor ensures the safety and restoration at its own expense of exits and congresses damaged in the process of work for people with limited mobility and other elements of roads.
Before laying the a/b mixture, the underlying layer is treated with a bituminous emulsion without fail.
The Contractor ensures the timely removal of construction debris, does not allow unauthorized storage of waste on the surface or lawns.
The Contractor, at the request of the Customer, is obliged to provide information on the progress of work no later than 2 hours after notification of the provision of information. The date of receipt of the notification is the date and time recorded on the Customer's transmitting devices (fax, telephone, e-mail, etc.).
The Contractor ensures the examination of the hidden works and the coordination of the work performed in the operating organization;
The work of the personnel is carried out only in a single uniform with the obligatory logo of the enterprise (indicating the name of the organization, address, telephone).
If there are comments requiring re-laying of asphalt concrete pavements, the Contractor, at his own expense, re-lays the pavements.
The contractor is liable for harm and damage caused to third parties in the process of performing work under the contract.
Sanctions imposed on the Customer by regulatory organizations (traffic police, etc.) are subject to payment at the expense of the Contractor with the provision of payment confirmations to the Customer.
Perform the entire scope of work with your own materials, forces and means.
The Contractor is liable for harm and damage caused to the health and property of third parties arising through his fault during the period of repair work and the warranty period.
In the production of repair work, use modern building materials. All materials supplied for repair must have appropriate certificates and other documents certifying their quality. Copies of certificates, etc. must be submitted to the Customer before the commencement of work performed using the relevant materials. The contractor is responsible for the compliance of the materials used with state standards and specifications. The quality of the work performed by the Contractor must comply with the requirements of SNiP 3.06.03-85 "Motorways", GOST R 50597-93 "Motorways and Streets Requirements for the operational condition acceptable under the terms of road safety".
The quality of the asphalt concrete mixture used and the degree of its compaction on the roadway must comply with the requirements of SNiP 3.06.03-85 p1-11 "Roads", GOST 31015-2002 "Asphalt concrete mixtures and crushed stone-mastic asphalt concrete. Specifications”, GOST 9128-2013 “Interstate standard Mixtures of asphalt concrete, polymer asphalt concrete, asphalt concrete, polymer asphalt concrete for highways and airfields”.
The contractor is responsible for the compliance of the materials used with state standards and specifications. The quality of the services provided by the Contractor must comply with the requirements of GOST, SNiP and industry instructions for these types of work.
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