Pothole repair in winter technology. Asphalt paving technology
MINISTRY OF TRANSPORT OF THE RUSSIAN FEDERATION
STATE ROAD SERVICE
(ROSAVTODOR)
CENTRE
ORGANIZATION OF LABOR AND ECONOMIC
MANAGEMENT METHODS
(TSENTRORGTRUD)
COLLECTION OF CARDS
WORK PROCESSES FOR REPAIR AND
ROAD MAINTENANCE
Work process map
Pothole repair of asphalt concrete pavements
for pothole depths up to 50 mm
using machines ED-105
KTP-1.01-2001
Second edition, revised and enlarged.
(Issue 1)
Moscow, 2001
Work process maps are designed to improve the organization of labor for workers involved in repair and maintenance highways.
Maps define progressive work technology, rational use working time, technological sequence of work performance based on advanced techniques and methods of work.
The maps can be used in the development of organizational and technological documentation for the repair and maintenance of roads (PPR and others), work planning, as well as for educational purposes in the preparation of highly qualified workers.
A collection of maps of labor processes was prepared by engineers A.I. Anashko, E.V. Kuptsova,
T.V. Insurance.Responsible for the release of A.A. Morozov.
. Scope and effectiveness of the map
Note: The labor costs on the map include time for preparatory and final work - 5% and rest - 10%.
Using the methods and techniques of labor recommended by the map will increase output by 8%.
. Preparation and conditions for the execution of processes
3.3 . Overalls and footwear.
1 . Cotton semi-overalls 4
2 . Boots leather 4 pairs
3 . Canvas mittens 3 pairs
4 . Mittens combined 1 pair
5 . Tarpaulin knee pads 3 pairs
6 . Signal vest 3 pcs.
3.4 . The need for materials per 10 m 2 of the repaired area with a pothole depth of up to 50 mm: hot fine-grained asphalt concrete mixture ( GOST 9128-84 ) - 1.19 t; liquid bitumen - 5 l; diesel fuel.
4. Process technology and labor organization
4.1 . Works on patching of asphalt concrete pavements using ED-105 machines for the repair of asphalt concrete pavements are carried out in the following technological sequence:
Installation and removal of fences and transitions of workers at a distance of up to 50 m;
Breaking and cutting off the edges of the cover of the repaired hole with a jackhammer;
Cleaning pits from dust, dirt and debris;
Bitumen lubrication of the edges of the coating and base;
Laying and leveling of asphalt mix;
Rolling the mixture with a vibrating manual roller;
Bitumen heating with bitumen boiler maintenance;
Maintenance of the compressor and generator.
4.3 . Workplace organization scheme
M 1, A 1, A 2, A 3 - location of workers; 1 - inventory barrier; 2- road sign; 3- guide cones; 4 - potholes on the coating; 5 - road sign; 6 - road sign; 7 - black coating repair machine; 8 - map-cutting filled with asphalt concrete mix. The arrow indicates the direction of movement of the link.
Scheme of arrangement of road signs at repair work ah (detour on the roadway).
Breaking and trimming the edges of the coverings of the repaired hole with a jackhammer
13.4. Pothole repair of asphalt concrete and bituminous materials. The main methods of patching and technological operations
The task of patching is to restore the continuity, evenness, strength, grip and water resistance of the coating and ensure normative term refurbished site services. When patching, various methods, materials, machines and equipment are used. The choice of one or another method depends on the size, depth and number of potholes and other defects in the coating, the type of coating and the materials of its layers, available resources, weather conditions, requirements for the duration of repair work, etc.
The traditional method involves trimming the edges of the pothole to give it a rectangular shape, cleaning it from asphalt concrete scrap and dirt, priming the bottom and edges of the pothole, filling it with repair material and compacting. To give the pothole a rectangular shape, small cold milling machines, circular saws, and punchers are used.
As a repair material, asphalt concrete mixtures that require compaction are mainly used, and from the means of mechanization, small-sized rollers and vibrorammers are used.
When working in conditions of increased moisture, potholes are dried before priming with compressed air (hot or cold), as well as using infrared burners. If the coating is repaired with small cards (up to 25 m 2), the entire area is heated; when repairing large maps - along the perimeter of the site.
After preparation, the pothole is filled with repair material, taking into account the margin for compaction. With a pothole depth of up to 5 cm, the mixture is laid in one layer, more than 5 cm - in two layers. Compaction is carried out from the edges to the middle of the repaired areas. When filling potholes deeper than 5 cm, a coarse-grained mixture is placed in the bottom layer and compacted. This method allows you to get a high quality repair, but requires a significant number of operations. It is used in the repair of all types of coatings made of asphalt concrete and bitumen-mineral materials.
Small potholes up to 1.5-2 cm deep on an area of 1-2 m 2 or more are repaired by the method of surface treatment using crushed stone of fine fractions.
The repair method with heating the damaged pavement and reusing its material is based on the use of special equipment for heating the pavement - an asphalt heater. The method makes it possible to obtain a high quality of repair, saves material, simplifies the technology of work, but has significant limitations due to weather conditions (wind and air temperature). It is applied at repair of all types of coverings from asphalt concrete and bituminous mixes.
The method of repair by filling potholes, pits and subsidence without cutting or heating the old pavement consists in filling these deformations and destructions with cold polymer-asphalt concrete mix, cold asphalt concrete, wet organo-mineral mix, etc. The method is simple to perform, allows you to work in cold weather with a wet and wet coating, but does not provide high quality and durability of the repaired coating. It is used when repairing pavements on roads with low traffic volumes or as a temporary, emergency measure on roads with high traffic volumes.
According to the type of repair material used, there are two groups of patching methods: cold and hot.
cold ways are based on the use of cold bitumen-mineral mixes, wet organic-mineral mixes (VOMS) or cold asphalt concrete as a repair material. They are mainly used for the repair of black gravel and cold asphalt concrete pavements on low-grade roads, as well as, if necessary, urgent or temporary filling of potholes in more early dates on high grade roads.
Work on patching by this method begins in the spring, as a rule, at an air temperature of at least + 10 ° C. If necessary, cold mixtures can be used for patching and at lower temperatures (from +5°C to -5°C). In this case, before laying, cold black crushed stone or cold asphalt concrete mixture is heated to a temperature of 50-70 ° C, with the help of burners, the bottom and walls of potholes are heated until bitumen appears on their surface. In the absence of burners, the surface of the bottom and walls is coated with bitumen with a viscosity of 130/200 or 200/300, heated to a temperature of 140-150°C. After that, the repair material is laid and compacted.
The formation of the coating at the place of repair in a cold way occurs under the traffic for 20-40 days and depends on the properties of liquid bitumen or bitumen emulsion, type of mineral powder, weather conditions, traffic intensity and composition.
Cold asphalt concrete layers for patching are prepared using liquid medium thickening or slow thickening bitumen with a viscosity of 70/130, using the same technology as hot asphalt concrete mixtures, at a bitumen heating temperature of 80-90 ° C and a mixture temperature at the outlet of the mixer 90-120 °C. Mixtures can be stored in stacks up to 2 m high. summer period they can be kept in open areas, in the autumn-winter period - in closed warehouses or under a canopy.
Repair work can be carried out at a lower air temperature, and repair material can be prepared in advance. The cost of work on this technology is lower than with the hot method. The main disadvantage is the relatively short service life of the repaired pavement on roads with the movement of heavy trucks and buses.
hot ways are based on the use of hot asphalt concrete mixtures as a repair material: fine-grained, coarse-grained and sandy mixtures, poured asphalt concrete, etc. The composition and properties of the asphalt concrete mixture used for repair should be similar to that of which the coating is made. The mixture is prepared according to the usual technology for the preparation of hot asphalt concrete. Hot methods are used in the repair of roads with asphalt concrete pavement. Works can be carried out at an air temperature of at least +10°C with a thawed base and a dry coating. When using a heater of the repaired coating, it is allowed to carry out repairs at an air temperature of at least +5°C. Hot patching methods provide higher quality and longer service life of the repaired pavement.
As a rule, all work on patching is carried out in early spring as soon as weather and surface conditions permit. In summer and autumn, potholes and pits are sealed immediately after they appear. Technology and organization of work in various ways have their own characteristics. However, for all methods of patching there are common technological operations that are performed in a certain sequence. All these operations can be divided into preparatory, main and final.
Preparatory work includes:
installation of fencing of work sites, road signs and lighting, if work is performed at night;
marking of places of repair (maps);
cutting, breaking or milling of damaged areas of the coating and cleaning of the removed material;
cleaning potholes from material residues, dust and dirt;
drying the bottom and walls of the pothole, if the repair is carried out in a hot way with a wet coating;
processing (priming) of the bottom and walls of the pothole with bitumen emulsion or bitumen.
The marking of repair sites (repair maps) is carried out using a stretched cord or chalk using a rail. The repair site is outlined by straight lines parallel and perpendicular to the axis of the road, giving the contour correct form and capturing an undamaged coating to a width of 3-5 cm. Several potholes located at a distance of up to 0.5 m from one another are combined into a common map.
Cutting, breaking or milling of the coating within the marked map is carried out for the thickness of the destroyed layer of the coating, but not less than 4 cm throughout the repair area. In this case, if the depth of the pothole has affected the lower layer of the coating, the thickness of the lower layer with the destroyed structure is loosened and removed.
It is very important to remove and remove the entire destroyed and weakened layer of asphalt concrete, capturing a strip of at least 3-5 cm wide from a strong, undestroyed asphalt concrete along the entire marked contour. These edge bands of the pothole cannot be left unremoved, since the solidity of the asphalt concrete is weakened here due to the formation of microcracks, loosening and chipping of individual gravel from the walls of the pothole (Fig. 13.10, a). Water collects in the pothole, which, under the dynamic influence of the wheels of cars, penetrates into the interlayer space and weakens the adhesion of the upper layer of asphalt concrete to the lower one. Therefore, if the weakened edges of the pothole are left, then after laying the repair material, after some time, the weakened edges may collapse, the newly laid material will lose its connection with the strong old material and the development of the pothole will begin.
Rice. 13.10. Cutting a pothole before laying the repair material: a - cutting weak spots; b- cutting the edges of the pothole after milling; 1 - weakened wall of the pothole; 2 - exfoliated part of the coating; 3 - destroyed part of the bottom of the pothole; 4 - chopped off or beveled wall of the pothole
The walls of the edges of the pothole after cutting should be vertical along the entire contour. Cutting and breaking of the coating can be carried out using a pneumatic jackhammer or scrap, a concrete breaker, a seam saw and a ripper, or using a road milling machine.
When using a road milling cutter for cutting a pothole, rounded front and rear wall potholes that must be trimmed with a circular saw or jackhammer. Otherwise top part the laid layer of repair material at the interface with the old material will be very thin and will quickly collapse (Fig. 13.10, b).
The loosened material of the old pavement is manually removed from the pothole, and when using a road milling machine, the removed material (granulate) is fed into a dump truck by a loading conveyor and taken out. The cleaning of the map is carried out with the help of shovels, compressed air, and with a large area of the map - with the help of sweepers. Drying of the bottom and walls of the card is carried out as necessary by blowing with hot or cold air.
Treatment with a binder (priming) of the bottom and walls of potholes is carried out in the case of laying hot asphalt mixes as a repair material. This is necessary in order to ensure better adaptation of the old asphalt concrete material to the new one.
The bottom and walls of the cleaned card are treated with liquid medium-thickening bitumen with a viscosity of 40/70, heated to a temperature of 60-70°C with a flow rate of 0.5 l/m 2 or a bituminous emulsion with a flow rate of 0.8 l/m 2 . In the absence of means of mechanization, bitumen is heated in mobile bitumen boilers and distributed over the base using a watering can.
Filling the pothole with repair material can only be done after all preparatory work. The laying technology and the sequence of operations depend on the method and volume of work performed, as well as on the type of repair material. With small volumes of work and the absence of mechanization, the laying of repair material can be done manually.
The temperature of the hot mix asphalt delivered to the place of laying should be close to the temperature of preparation, but not lower than 110-120°C. It is most expedient to lay the mixture at such a temperature when it is easily processed, and during the laying process, waves and deformations are not formed during the passage of the rink. Depending on the type of mixture and its composition, such a temperature is considered: for a multi-gravel mixture - 140-160 ° C; for medium crushed stone mixture - 120-140 ° C; for low gravel mixture - 100-130°C.
Laying the mixture in the card is carried out in one layer at a cutting depth of up to 50 mm and in two layers at a depth of more than 50 mm. In this case, a coarse-grained mixture with a crushed stone size of up to 40 mm can be laid in the lower layer, and only a fine-grained mixture with a fraction size of up to 20 mm can be placed in the upper layer.
The thickness of the laying layer in a loose body should be greater than the thickness of the layer in a dense body, taking into account the safety factor for compaction, which is taken: for hot asphalt mixes 1.25-1.30; for cold asphalt mixes 1.5-1.6; for wet organo-mineral mixtures 1.7-1.8, for crushed stone and gravel materials treated with a binder, 1.3-1.4.
When laying the repair material in a mechanized way, the mixture is fed from the thermos hopper through a rotary tray or a large-diameter flexible hose directly into the pothole and is evenly leveled over the entire area. The laying of asphalt concrete mixtures when embedding maps with an area of 10-20 m 2 can be carried out by an asphalt paver. In this case, the mixture is laid over the entire width of the map in one pass in order to avoid an additional longitudinal seam for conjugating the laying strips. The compaction of the asphalt concrete mixture laid in the bottom layer of the coating is carried out by pneumatic rammers, electric rammers or manual vibratory rollers in the direction from the edges to the middle.
The asphalt concrete mixture laid in the top layer, as well as the mixture laid in one layer with a pothole depth of up to 50 mm, is compacted with a self-propelled vibratory roller (first two passes along the track without vibration, and then two passes along the track with vibration) or light-type static smooth-roller rollers weighing 6-8 tons up to 6 passes along one track, and then heavy rollers with smooth rollers weighing 10-18 tons up to 15-18 passes along one track.
The compaction coefficient should be at least 0.98 for sandy and low-gravel asphalt concrete mixtures and 0.99 for medium- and high-gravel mixtures.
Compaction of hot asphalt mixes is started at the highest possible temperature at which deformations are not formed during the rolling process. Compaction should provide not only the required density, but also the evenness of the repair layer, as well as the location on the same level of the repaired coating with the old one. For better mating of the new coating with the old one and the formation of a single monolithic layer when laying hot mixes, the joint along the entire contour of the cutting is heated using a line of burners or an electric heater. The joints of potholes that protrude above the surface of the coating are eliminated by milling or grinding machines. The final work is the cleaning of the remaining repair waste with their loading into dump trucks and the removal of fences and road signs, the restoration of marking lines in the patching area.
The quality of the repair and the service life of the repaired coating depend primarily on compliance with the quality requirements for the performance of all technological operations (Fig. 13.11).
Rice. 13.11. The sequence of basic patching operations: a - correct; b- wrong; 1 - pothole before repair; 2 - cutting or cutting, cleaning and processing with a binder (priming); 3 - filling with repair material; 4 - seal; 5 - view of the repaired pothole
The most important requirements are:
repairs must be carried out at an air temperature not lower than that allowed for this repair material on a dry and clean surface;
when cutting down the old coating, weakened material should be removed from all areas of the pothole where there are cracks, breaks and spalling; the repair card must be cleaned and dried;
the shape of the repair map must be correct, the walls are sheer, and the bottom is even; the entire surface of the pothole must be treated with a binder;
repair material must be laid at optimum temperature for this type of mixture; the layer thickness should be greater than the depth of the pothole, taking into account the margin for the compaction factor;
the repair material must be carefully leveled and compacted flush with the surface of the coating;
the formation of a layer of new material on the old coating at the edge of the map is not allowed to avoid shocks when a car runs over and the rapid destruction of the repaired area.
The result of a properly executed repair is the height of the laid layer after compaction, exactly equal to the depth of the pothole without unevenness; correct geometric shapes and invisible seams, optimal compaction of the laid material and its good connection with the material of the old pavement, long service life of the repaired pavement. The result of an incorrectly performed repair may be unevenness of the compacted material, when its surface is higher or lower than the surface of the pavement, arbitrary map shapes in plan, insufficient compaction and poor connection of the repair material with the material of the old pavement, the presence of protrusions and sags on the edges of the map, etc. Under the influence of transport and climatic factors areas of such repair are quickly destroyed.
Pothole repair of black crushed stone or gravel coatings. When repairing such pavements, simpler materials and repair methods can be used to reduce the cost of maintaining roads with black gravel and black gravel pavements. Most often, these methods are based on the use of cold bituminous mineral mixtures or materials treated with bitumen emulsion as a repair material. One of these materials is a mixture of organic binder (liquid bitumen or emulsion) with wet mineral material (crushed stone, sand or gravel-sand mixture), laid in a cold state. Cement or lime is used as an activator when using liquid bitumen or tar.
So, for example, to repair potholes up to 5 cm deep, a repair mixture is used in the composition: crushed stone 5-20 mm - 25%; sand - 68%; mineral powder - 5%; cement (lime) - 2%; liquid bitumen - in excess of 5% mass; water - about 4%.
The mixture is prepared in forced action mixers in the following sequence:
mineral materials are loaded into the mixer at natural humidity(crushed stone, sand, mineral powder, activator), mix;
add the calculated amount of water and mix;
enter the organic binder, heated to a temperature of 60°C, and finally mix.
The amount of water introduced is adjusted depending on the intrinsic moisture content of the mineral materials.
During the preparation of the mixture, mineral materials are not heated or dried, which greatly simplifies the preparation technology and reduces the cost of the material. The mixture can be prepared ahead of time.
Before laying the mixture, the bottom and walls of the pothole are not primed with bitumen or emulsion, but moistened or washed with water. The laid mixture is compacted and movement is opened. The final formation of the layer occurs under the traffic.
Patching with the use of wet bitumen-mineral mixtures can be carried out at a positive temperature not higher than +30°C and at a negative temperature not lower than -10°C in dry and damp weather.
Pothole repair of black gravel coatings by impregnation. As a repair material, crushed stone is used, pre-treated in a mixer with hot viscous bitumen in an amount of 1.5-2% by weight of crushed stone.
After marking the contour of the pothole, its edges are cut off, old coatings are scraped off and loosened material is removed, the bottom and walls of the pothole are treated with hot bitumen at a flow rate of 0.6 l / m 2. Then, black crushed stone with a fraction of 15-30 mm is laid and compacted with a manual rammer or vibratory roller; bitumen is poured with a flow rate of 4 l / m 2; lay the second layer of black crushed stone with fractions of 10-20 mm and compact it; crushed stone is treated with bitumen at a rate of 2 l/m 2 ; scatter stone screenings of fractions of 0-10 mm and compact with a pneumatic vibrating roller. Using the same technology, it is possible to carry out repairs by impregnation and using crushed stone not treated with bitumen. This increases the bitumen consumption: at the first spill - 5 l/m 2 , at the second - 3 l/m 2 . The distributed bitumen impregnates the layers of crushed stone to the full depth, as a result of which a single monolithic layer is formed. This is the essence of the impregnation method. For impregnation apply viscous bitumen 130/200 and 200/300 at a temperature of 140-160°C.
A simplified method of patching with impregnation of crushed stone with bitumen emulsion or liquid bitumen is widely used in France for patching small potholes on roads with low and medium traffic. Such potholes are called "chicken nest".
The repair technology consists of the following operations:
first, potholes or pits are manually covered with large-sized crushed stone - 10-14 or 14-25 mm;
then, as it is filled, small crushed stone of fractions of 4-6 or 6-10 mm is scattered until the road profile is completely restored;
binder is poured: bitumen emulsion or bitumen in a ratio of 1:10, i.e. one part binder per ten parts crushed stone by weight;
compaction is carried out manually using a vibrating plate.
The binder penetrates the crushed stone layer to the base, as a result of which a monolithic layer is formed. The final formation occurs under the action of moving cars.
In addition to direct impregnation for patching, the reverse impregnation method is used. In this case, bitumen with a viscosity of 90/130 or 130/200, heated to a temperature of 180-200°C, is poured onto the bottom of the prepared card. The thickness of the bitumen layer should be equal to 1/5 of the depth of the pothole. Immediately after the spill of hot bitumen, mineral material is poured: crushed stone of fractions 5-15; 10-15; 15-20 mm, ordinary crushed stone or gravel-sand mixture with a particle size of up to 20 mm. The mineral material is leveled and compacted with a rammer.
When the mineral material, which has natural moisture, interacts with hot bitumen, foaming occurs and the material is impregnated with bitumen from the bottom up. If the foam has not risen to the surface of the material, the binder is poured again at the rate of 0.5 l / m 2, covered with a thin layer of crushed stone and compacted.
With a pothole depth of up to 6 cm, all its fillings are performed in one layer. At a greater depth, filling is carried out in layers 5-6 cm thick. Patching works can be performed in this way even at negative air temperatures. However, the service life of the repaired sections in this case is reduced to 1-2 years.
Pothole repair using crushed stone treated with bituminous emulsion has a number of advantages: there is no need to heat the binder to prepare the mixture; can be laid at a positive ambient temperature, i.e. from the beginning of spring to the end of autumn; rapid disintegration of the cationic emulsion, which contributes to the formation of a repair layer; no edge trimming, material removal or priming.
To perform work, a repair vehicle is used, which includes: a base vehicle with a heat-insulated emulsion tank with a capacity of 1000 to 1500 liters; distribution device for emulsion (compressor, hose, nozzle); bunkers of crushed stone of fractions from 2-4 to 14-20. The cationic emulsion used must be fast disintegrating, contain 65% bitumen and be kept warm at temperatures between 30°C and 60°C. The surface to be treated must be clean and dry.
The technology for repairing deep pits over 50 mm of the "chicken's nest" type (French terminology) consists of the following operations: laying a layer of crushed stone of fraction 14-20; distribution of binder on a layer of crushed stone 14-20; laying the 2nd layer of crushed stone 10-14; spraying binder on a layer of crushed stone 10-14; laying the 3rd layer of crushed stone 6-10; spraying binder on a layer of crushed stone 6-10; laying the 4th layer of crushed stone 4-6; spraying binder on a layer of crushed stone 4-6; laying the 5th layer of crushed stone 2-4 and compaction.
It is important to ensure the correct dosing of the binder when spraying the emulsion over crushed stone. Crushed stone should only be covered with a binder film, but not drowned in it. The total consumption of the binder should not exceed the ratio binder: crushed stone = 1:10 by weight. The number of layers and the size of crushed stone fractions depends on the depth of the pothole. When repairing small potholes up to 10-15 mm deep, the repair is carried out in the following order: laying a layer of crushed stone 4-6; spraying binder on crushed stone 4-6; crushed stone distribution 2-4 and compaction.
These methods are applicable in the repair of black gravel and black gravel pavements on roads with low traffic volumes. The disadvantages of using such methods are that the presence of a layer of variable thickness can cause destruction of the edges of the patch, and the appearance of the patch repeats the outlines of the pothole.
Pothole repair of asphalt concrete pavements using an asphalt heater. The technology of work is greatly simplified in the case of patching with preliminary heating of the asphalt concrete pavement over the entire area of the map. For these purposes, a special self-propelled machine can be used - an asphalt heater, which allows you to heat the asphalt concrete pavement up to 100-200 ° C. The same machine is used for drying repaired areas in wet weather.
The heating mode consists of two periods: heating the coating surface to a temperature of 180°C and further more gradual heating of the coating over the entire width to a temperature of about 80°C in the lower part of the heated layer at a constant temperature on the coating surface. The heating mode is regulated by changing the gas flow rate and the height of the burners above the coating from 10 to 20 cm.
After heating, the asphalt concrete pavement is loosened with a rake to the entire depth of the pothole, a new hot asphalt concrete mixture is added to it from the thermos hopper, mixed with the old mixture, distributed over the entire width of the map with a layer 1.2-1.3 times greater than the depth, taking into account the compaction coefficient and compact from the edges to the middle of the repaired area with a manual vibratory roller or a self-propelled roller. The junctions of the old and new coatings are heated using a line of burners that are part of the asphalt heater. The line of burners is a mobile metal frame with infrared burners mounted on it, which are supplied with gas from cylinders through a flexible hose. During the repair work, the temperature of the coating should be in the range of 130-150°C, and by the end of the compaction work - not lower than 100-140°C.
The use of an asphalt heater greatly simplifies the technology of patching and improves the quality of work.
The use of gas-fired asphalt heaters requires special attention and compliance with safety regulations. It is not allowed to operate gas burners at a wind speed of more than 6-8 m / s, when a gust of wind can extinguish the flame on part of the burners, and the gas from them will flow, concentrate in large quantities and may explode.
Asphalt heaters operating on liquid fuel or with electrical sources of infrared radiation are much safer.
Repair of asphalt concrete pavements with the use of special machines for patching or road repairers. The most effective and high-quality type of patching is the repair performed using special machines, which are called road repairers. Road repairers are used as a means of complex mechanization of road repair work, since they are used not only to patching pavement, but also crack bridging and grouting.
The technological scheme of patching with the use of a road repairer includes the usual operations. If the repairer is equipped with a heater, the repair technology is greatly facilitated.
Simplified methods of patching (injection methods). In recent years, simplified methods of patching using special machines such as Savalco (Sweden), Rasko, Dyura Petcher, Blow Petcher, etc. have become more widespread. In Russia, similar machines are produced in the form of special trailed equipment. - sealer brand BCM-24 and UDN-1. Repair of potholes by injection is performed using a cationic emulsion. Cleaning the pothole for repair is carried out with a jet of compressed air or by suction; primer - heated to 60-75 ° C emulsion; filling - with blackened crushed stone in the process of injection. With this repair method, edge trimming can be omitted.
As a repair material, crushed stone of a fraction of 5-8 (10) mm and an emulsion of the EBK-2 type are used. A concentrated emulsion (60-70%) is used on bitumen BND 90/130 or 60/90 with an approximate consumption of 10-11% by weight of crushed stone. The surface of the repaired area is sprinkled with white gravel with a layer of one gravel. The traffic opens in 10-15 minutes. Works are carried out at an air temperature of at least +5 ° C, both on dry and wet surfaces.
Patch repair by injection is performed in the following order (Fig. 13.12):
Rice. 13.12. Pothole repairs according to a simplified technology: 1 - cleaning potholes by blowing with compressed air; 2 - priming with bituminous emulsion; 3 - filling with crushed stone treated with emulsion; 4 - applying a thin layer of raw gravel
the first stage - the place of the pit or patch is cleaned with a jet of air under pressure to remove pieces of asphalt concrete, water and debris;
the second stage - priming with a bitumen emulsion of the bottom, walls of the pothole and the surface of the asphalt concrete pavement adjacent to it. The emulsion flow is controlled by a control valve on the main nozzle. The emulsion enters the air stream from the spray ring. The temperature of the emulsion should be about 50°C;
the third stage is filling the pothole with repair material. Crushed stone is introduced into the air stream using a screw conveyor, then it enters the main mouthpiece, where it is covered with an emulsion from a spray ring, and from it the processed material with high speed thrown into the pothole, distributed in thin layers. Compaction occurs due to the forces resulting from the high speeds of the ejected material. The suspended flexible hose is controlled remotely by the operator;
the fourth stage is the application of a protective layer of dry, untreated crushed stone to the patch area. In this case, the valve on the main nozzle that controls the flow of the emulsion is turned off.
It should be noted that the exclusion of pre-cutting the edges of the pothole leads to the fact that in the marginal zone of the pothole there remains old asphalt concrete with a disturbed structure, which, as a rule, has reduced adhesion to the underlying layer. The service life of such a patch will be less than with traditional technology. In addition, patches have irregular shapes, which impairs the appearance of the coating.
Pothole repairs using cast asphalt mixes. A distinctive feature of cast asphalt mixes is that they are laid in a fluid state, as a result of which they easily fill potholes and do not require compaction. Fine-grained or sandy cast asphalt can be used for repairs at low air temperatures (down to -10°C). Most often, a sandy cast asphalt concrete mixture is used for repair work, consisting of natural or artificial quartz sand in an amount of 85% by weight, mineral powder - 15% and bitumen - 10-12%. For the preparation of cast asphalt, viscous refractory bitumen with a penetration of 40/60 is used. The mixture is prepared in mixing plants with forced action mixers at a mixing temperature of 220-240°C. Transportation of the mixture to the place of laying is carried out in special mobile boilers of the Kocher type or in thermos bunkers.
The delivered mixture at a temperature of 200-220°C is poured into the prepared pothole and easily leveled with wooden trowels. The easily moving mixture fills all the irregularities, due to the high temperature it heats up the bottom and walls of the pothole, as a result of which a strong connection of the repair material from the side of the coating is achieved.
Since a fine-grained or sandy cast mixture creates a surface with increased slipperiness, measures must be taken to improve its grip. For this purpose, immediately after the mixture is distributed, black crushed stone 3-5 or 5-8 is scattered over it with a consumption of 5-8 kg / m 2 so that the crushed stone is evenly distributed in a layer of one crushed stone. After the mixture has cooled down to 80-100°C, crushed stone is rolled with a manual roller weighing 30-50 kg. When the mixture has cooled to ambient temperature, the excess gravel that has not sunk into the mixture is swept away and movement is opened.
Laying of cast asphalt mixes during patching can be done manually or with a special asphalt paver with a heating system. The advantage of this technology lies in the fact that the operations of priming the repair card and compacting the mixture are excluded, as well as the high strength of the repair layer and the reliability of the joints of the interface of new and old materials. The disadvantages are the need to use special mixers, heated mobile rollers and mixers or thermos bunkers, viscous refractory bitumen, as well as increased safety and labor protection requirements when working with a mixture that has a very high temperature.
In addition, poured asphalt during operation has a significantly greater strength and lower deformability compared to conventional asphalt concrete. Therefore, in the case when poured asphalt is repairing a coating of conventional asphalt concrete, after a few years this coating begins to collapse around the patch of poured asphalt, which is explained by the difference in the physical and mechanical properties of the old and new material. Molded asphalt is most often used for patching city roads and streets.
One of the ways to simplify the work technology and increase the construction season is the use of cold asphalt concrete mixtures based on polymer bitumen binder (PBV) as a repair material. These mixtures are prepared using a complex binder, which consists of bitumen with a viscosity of 60/90 in an amount of about 80% by weight of the binder, a polymer modifying additive in an amount of 5-6% and a solvent, for example diesel fuel, in the amount of 15% by weight of the binder. The binder is prepared by mixing the components at a temperature of 100-110°C.
Asphalt-concrete mix on PMB is prepared in mixers with forced mixing at a temperature of 50-60°C. The mixture consists of fine crushed stone fractions 3-10 in the amount of 85% by weight of the mineral material, screenings 0-3 in the amount of 15% and a binder in the amount of 3-4% of the total mass of the mineral material. The mixture is then stored in an open stack, where it can be stored for up to 2 years, or loaded into bags or barrels, in which it can be stored for several years, retaining its technological properties, including mobility, plasticity, lack of caking and high adhesive characteristics.
The repair technology using this mixture is extremely simple: the mixture from the body of a car or from the bunker of a road repairer is manually or using a hose fed into a pothole and leveled, after which traffic is opened, under the influence of which the road layer is formed. The whole process of repairing a pothole takes 2-4 minutes, since operations for marking the map, cutting and cleaning the pothole, as well as compacting with rollers or vibratory rollers are excluded. The adhesive properties of the mixture are also preserved when it is laid in potholes filled with water. Repair work can be carried out at negative air temperatures, the limit of which needs to be clarified. All this makes this method of patching very attractive for practical purposes.
However, it also has a number of significant drawbacks. First of all, there is a possibility of rapid destruction of the repaired pothole due to the fact that its weakened edges are not removed. When performing work in wet weather or in the presence of water in a pothole, part of the moisture can get into microcracks and pores of the old coating and freeze when the coating temperature drops below 0. In this case, the process of destruction of the zone of conjugation of new and old materials can be initiated. The second disadvantage of this method of repair is the preservation of the irregular external shape of the pothole after repair, which worsens the aesthetic perception of the road.
Availability a large number methods of patching makes it possible to choose the optimal one based on specific conditions, taking into account the condition of the road, the number and size of coating defects, the availability of materials and equipment, the timing of repairs and other circumstances.
In any case, it is necessary to strive to eliminate pitting at an early stage of its development. After patching, in many cases it is advisable to arrange a surface treatment or lay a protective layer, which will give a uniform appearance to the coating and prevent its destruction.
Environmental friendliness
Price
Practicality
Appearance
Ease of manufacture
Labor intensity when using
final grade
On the this moment is considered the most popular material used for paving. He is reliable enough. At the same time, asphalt markings with the best performance are intended for heavy loads, for example, such as M1200. A material of slightly lower density (M1000) is no longer able to withstand the weight of numerous machines, so it is usually used only for laying paths and sidewalks.
Initially, it is necessary to mark the area on which asphalt is supposed to be laid. All work will depend on the purpose for which the coating is intended to be used. So, for an “easy” route, along which a large traffic flow is not expected, only one layer of crushed stone will be needed, but when building a highway, it will already be necessary to use at least three of its layers.
Fractions are stacked from largest to smallest and are very carefully rolled with a roller. At the first stage, it is necessary to form a special cushion on which the asphalt will be located.
If it is necessary for the coating to run flush with surrounding area, then you first need to dig a pit of the required depth, and after laying rubble in it, proceed directly to pouring the asphalt mass. All Men at work asphalt laying is carried out in accordance with the requirements of SNIP and GOST.
There are two main ways to build asphalt roads:
- Cold. Usually suitable for repairs, as it sets very quickly and it will soon be possible to use the coating to the fullest;
- Hot. Applicable when laying a new road. In this case, the bituminous mixture must be rolled before it begins to cool.
The consumption of bitumen during the repair of the coating should be at least 0.5 liters. But the consumption of asphalt when laying a new route is calculated separately. Here it is necessary to take into account not only the size of the road, but also its structure, as well as other additional factors.
When working, be sure to use a special thermometer that allows you to determine the temperature of the building material. Constant monitoring of this indicator is important, since after cooling, the bitumen will no longer be suitable for laying a road.
On the video - the technology of laying cold asphalt:
Application of impregnation
At the moment, there are three types of impregnations that are part of the road surface:
- Based on acrylic polymer. One of the expensive coatings, which is used only in limited areas. For example, such as tennis courts. They provide highest quality protection, as well as available in several colors.
- Coal tar. A modified coating that is able to resist the effects of petroleum products. Thanks to special components, not only long-term service is ensured, but also high-quality color.
- asphalt emulsion. It is quite common and affordable, but does not provide adequate protection, which is why the canvas may soon require repair.
When cracks form on the laid asphalt, the bituminous mixture is no longer used as a fill. For this purpose, a sealant is used, which is then sprinkled with a fine crumb of cement. Prevent their occurrence and ensure the best strength allows the use of special grids for asphalt. With the help of them, a reliable coupling of the coating is made, and its service life is improved and extended.
Seal- this is very milestone when laying the cover. For this purpose, it is possible to use special paving machines: a roller, a vibrating plate or an asphalt paver. Each of these types of equipment is quite mobile, but has some advantages over other types of rolling. So, the vibrating plate has the best maneuverability, and the asphalt paver can carry out at least two types of work.
In the photo - the process of compaction of the coating when laying asphalt
Do-it-yourself asphalt laying
In private construction, using asphalt, blind areas are made, paths and sidewalks are arranged. In addition, asphalt can be used to form roofing and interior work.
When laying tracks on your own, the work is done in stages:
- Initially, up to 30 cm of soil is removed and all debris is removed;
- Next, curbs are installed, which will serve not only as an additional decoration, but also prevent the spread of bitumen;
- On the this stage pillow is created. The crushed stone layer should reach 15 cm, after rolling which you can pour a finer fraction of crushed stone and roll it again. The last layer will be sand. It will be enough 5 cm. After creating such a pillow, you will need to fill it with water and roll it with a hand roller;
- Hot asphalt must be evenly scattered around the entire perimeter of the track. Further, to level the bumps, it is necessary to use a mop-engine, gradually filling all the pits with new portions of asphalt. Since the material hardens quickly enough, several workers are needed to carry out all the work;
- When the road section is filled with asphalt and leveled, it is necessary to compact it with a hand roller. You will first need to lubricate the roller with diesel fuel in order to prevent sticking and ensure uniform coverage. It is important to cover with diesel fuel all the tools that work is done.
The temperature of the asphalt during paving is very important. It should not fall below 120C, otherwise the coating will soon become completely unusable.
When laying, it is important to make only direct movements, reverse ones are strictly prohibited. Bitumen consumption in this case is calculated individually and can be either 5 or 10 kg. At the end of work, instead of impregnation, you can use special paint for asphalt. She will give required shade. In addition, you can use white paint for marking asphalt.
How to lay (lay) asphalt with your own hands will tell the video:
Roadbed repair
After some time, the bitumen will need to be repaired. If it is carried out on time, replacing the most worn out areas, then it will last much longer. long term. The most important part of the repair phase is milling. It involves the removal of the old coating with a cutter.
After that, surface texturing is carried out. Hot milling technique involves first warming up asphalt pavement, but with the cold method, this is not considered mandatory. The latter is practically indistinguishable in quality from hot, but it is able to facilitate the work several times.
The seam cutter is also designed for removing the coating, as well as for cutting seams. For the transportation of asphalt mass, a coher is used, which is specially made for this purpose. It can be both mobile and stationary.
To minimize the use manual labor, in many cases integers are used. automated systems. For example, for road repair, asphalt stripping machines are widely used, which carry out milling and cutting of unsuitable pavement using a diamond blade.
Removing asphalt with a floor cutter
patching
The entire canvas is not always repaired. Most often, the pitting technique is used, the technology of which involves filling all potholes and cracks with bituminous mass. It can be used when damage does not exceed 15% of total number defects.
Before proceeding with the repair, it will be necessary to carry out preparatory work:
- Markup. In this case, it is necessary to mark not only the damaged area, but also a certain amount of the whole canvas. If several potholes are located in the same radius, then they must be painted with a common contour.
- Next, the damaged asphalt layer is dismantled using, for example, a jackhammer. It is best to use the cold milling method, as it allows you to create even walls.
- At this stage, debris and coating crumbs are removed, after which potholes can be treated with a special bitumen composition.
On the video - how asphalt is laid using the UYAR-01 patching machine:
Material evaluation
Having considered in the article the use of asphalt pavement and the most important aspects repair, it can be described as follows:
- Bitumens used in modern laying of coatings are considered the most environmentally friendly, in comparison with similar material of past years;
- Available to many segments of the population, but still quite expensive;
- Let's apply to creation practically of all coverings. Additionally, it can be used in the construction of structures;
- The coating put into operation has a fairly good appearance. Over time, bitumen can fade, but the color can be maintained with the help of special paints;
- Impossible to make by yourself;
- Requires fairly quick skill and the use of additional workers, as it can quickly cool down and become unusable.
Surely, many of us have seen that roads are being repaired at any time of the day and under any weather conditions. Very often, asphalt is laid in heavy rain, and pits on the roads are repaired with the onset of frost. Of course, we are indignant: we found when to repair! However, as it turns out, we are not always right.
In fact, there are many ways to lay and repair asphalt roads. Some methods do not allow construction works in the rain, others cannot be carried out when negative temperatures, and others, as it turned out, are just designed to repair roads in frost and with any climatic precipitation. It's about about road repair modern materials, like cold asphalt and poured asphalt concrete
This type of material for road repair is very popular precisely because of the possibility of working in any weather. In addition, the technology of laying cold asphalt is very simple and consists of several stages.
Advantages and disadvantages of cold asphalt
Like any product, these mixtures have both their advantages and disadvantages over other road repair methods. Let's start with the pros of this material.
- Can be used in any weather.
- It is intended for work at negative temperatures.
- Fits easily.
- It does not require special skills and the use of special equipment.
- Repair does not require high costs.
- Movement on the repaired site can be carried out immediately after the completion of repair work.
The main disadvantage of cold asphalt is its high cost compared to hot asphalt. However, since cold asphalt is used for patching roads, its use is more cost-effective. Imagine that in order to repair a hole in the yard you need to: a) buy a bag of cold asphalt for 520 rubles, clean the pit with an ordinary broom, fill in the mixture and drive through it several times by car; b) bring a team of workers, outline the pit with the help of special equipment, deliver it to special car hot mix asphalt, tamp the mixture with a vibrating plate or a conventional roller. Obviously, only the delivery of special equipment to the place of work will cost several times more. Another disadvantage is the timing of stabilization of the mixture. Although traffic is allowed on the repaired area, it should be noted right away that if the traffic is too heavy (for example, motorways), the binder can be “carried away” on wheels. Vehicle. That is why cold asphalt is used for quick repair of roads of the 3rd and 4th category, as well as for the repair of sidewalks and yard roads.
Advantages and disadvantages of poured asphalt
In accordance with GOST R 54401-2011 “Road cast hot asphalt concrete. Technical requirements" cast asphalt concrete mix - "casting mix, with minimal residual porosity, consisting of a grain mineral part (crushed stone, sand and mineral powder) and viscous petroleum bitumen (with or without polymer or other additives) as a binder, laying which is produced by injection technology, without sealing, at a mixture temperature of at least 190 ° C. Cast asphalt concrete, depending on the temperature, as well as the magnitude and time of application of the load, manifests itself as an elastic-elastic and viscous-plastic material. The difference between cast polymer asphalt concretes is that they are produced using bitumen modified with polymer additives, polymer-bitumen binder. (WIKIPEDIA)
Main advantages
asphalt paving at any temperature
no roller required for leveling
wear resistance
durability
does not require relief preparation
better wheel grip
disadvantages
high price
delivery only in special bunkers - cochers
Summing up, it is worth noting that there are many ways to repair roads, which have their own pros and cons and their own characteristics. Answering the question whether it is possible to repair roads in winter, we showed that there are special technologies that allow urgent patching under any weather conditions. So if you urgently need to repair the road in front of your house, but you don’t want to wait for the summer, you can safely use cold asphalt, in cases where the areas are large and high demands are made on the quality of the coating, it is better to use
Is it possible to lay asphalt in puddles, mud or just on snow? infographics
Editorial responseMany have repeatedly observed the process of laying asphalt in winter or late autumn. But hardly anyone tried to penetrate into technical features this process. It turns out that it is possible to repair roads at this time of the year, but under certain circumstances.
According to the current Soviet SNIPs, asphalt cannot be laid at temperatures below +15, but now new materials and technologies have appeared that allow you to perform work even at sub-zero temperatures. But not below -10 ºС.
What needs to be done to lay asphalt in winter?
To repair the road in winter, it is necessary to prepare the area: remove snow, ice and treat the place with special reagents.
Rain and snow reduce the temperature of the mix, so thick asphalt layers are not recommended in wet weather. Lay pavement during light precipitation it is possible only along the entire width of the road, and not in parts in different days. In a downpour and a snowstorm, laying the canvas is impossible.
How is asphalt laid?
Asphalt laying consists of the following steps: the cleared area for the new route is covered with rubble. Then pour the emulsion, which should ensure the fixation of the asphalt. Another layer of bitumen and dry gravel is applied on top, the surface is leveled with a roller.
Why do holes and cracks appear on the road?
When laying asphalt, road services often save money. First of all, on an emulsion, the task of which is to hold the rubble. As a result, the asphalt is laid on a dry surface, so it quickly begins to disperse, forming cracks.
The second thing they are trying to save on is crushed stone. Instead, they can put a chipped brick under the asphalt, which is incomparable in strength with gravel. As a result, the asphalt fails, forming holes. According to the regulations, for an “easy” road, one layer of medium fraction (20-40 mm) is enough. If this is a highway, then it is recommended to lay crushed stone in several layers: the first layer is from a large fraction (40-70 mm), followed by a medium one, the last one is from a fine one (5-20 mm). The main thing is to roll each layer with a roller.
Road builders also save on the surface itself - asphalt. It, like bitumen emulsion, is made from oil. But not every grade of this raw material is suitable for high-quality road laying. As a rule, builders do not check the quality of oil, hence the fragility of the coating. The thickness of the asphalt depends on the intended use of the road. The minimum thickness is 4-5 cm (for yard areas, etc.). At high intensity traffic asphalt is again laid in layers, using different grain sizes. Coarse-grained asphalt concrete is placed in the first layer, fine-grained concrete is placed on top. For greater reliability, a third surface layer is placed. Before applying each next layer, the previous one is poured with bitumen.
Well, the main reason bad roads- negligence. Cracks often appear due to water that penetrates under the pavement and freezes during cold weather, thereby expanding holes in the roadway. Builders may neglect technical requirements and put the asphalt on the snow. In these actions lies not only negligence, but also the possibility of obtaining another order. You put it in a puddle - in a couple of months everything will be redone, so a new order is ready, and everything can be attributed to the harsh climate.
When should cold and hot asphalt be used?
There is a cold and hot way asphalt laying.
Cold laying is most often used in road repairs. The main thing in this process is to compact the coating well. The advantage of using cold asphalt is its all-weather application.
Work on the repair of the road can not be stopped even in winter.
There are several types of cold asphalt:
Summer cold asphalt. Temperature environment when laying from +15 to +30 °С.
Interseasonal cold asphalt. Ambient temperature during laying from -5 to +15 °C.
But this method is not suitable for the construction of a new road or overhaul old. In this case, resort to hot styling. Asphalt must be installed hot. However, in autumn and early spring to achieve quality repair roads using hot laying is difficult.
Instead, poured asphalt technology is used. Molded asphalt is a mixture of sand, gravel and crushed limestone with bitumen. Cast asphalt does not have to be rolled with rollers, its consistency is such that it lays down in a dense cast layer without the need for additional compaction. Molded asphalt is water resistant, so it can be laid even when it rains. The temperature of the poured asphalt during laying can vary between 200-250 degrees. The technology allows laying asphalt at -10 °C. The maximum thickness of the poured asphalt should not exceed 25-30 mm. Cast, like other types of asphalt, can be used not only in road construction, but also in such types of work as roofing, covering bridges, interior decoration.
Roads are measured to serve three years
Since 2011, new rules have come into force, according to which road repairs should be carried out not once every seven years, as it was before, but once every three years. According to officials, due to climatic conditions the road in Russia serves no more than three years.
In the same year, the capital's communal services began to keep the history of roads. The documents indicate when a particular kilometer of the highway was repaired. If a marriage is found, the contractors who carried out the work must correct the errors at their own expense.
Comparative cost of roads in Russia and abroad
Some road works in Russia cost many times more than the cost of roads abroad. The first in this list is the land that needs to be redeemed from the owners. In Russia, it is usually included in the cost of the project, but not in Europe. At the same time, the cost of land acquisition in Russia is 6-7% of the project cost, in the Moscow region - 30%, and in Moscow - up to 70%. Many people buy up the land adjacent to the future highway in advance and then sell it to the state at exorbitant prices.
The next most expensive is the cost of design. In Russia, there are virtually no standard road designs, so every new road have to be redesigned. Then the project is sent for state expertise, which is almost impossible to pass the first time. The re-examination costs up to 70% of the initial one - and this is without taking into account the cost of finalizing the project.
And the third is the delivery of materials. High-quality sand and gravel often have to be transported for tens or even hundreds of kilometers. A simple example: during the construction of some tunnels in the Olympic Sochi, finishes made in Krasnoyarsk were used. With delivery for five thousand kilometers.
As a result, it is not surprising that the construction of the Adler - Krasnaya Polyana road cost 285 billion rubles - 1.9 times more expensive than foreign analogues. In Europe, the cost of laying one kilometer of a tunnel in a mountain range is about $70 million.
The only reason why a road in Russia can be cheaper than a European one is thinner pavement, designed for a shorter service life. In Germany, the thickness of the top layer of asphalt should be 22 cm. In Russia - 8 cm. All this affects the service life. In addition, if the quality of the asphalt used can be checked, then the amount of sand and gravel cannot. Therefore, road builders use this: if you want, put less material If you want, indicate in the documents the delivery range of the required sand is 200 km, and bring the usual one from the nearest quarry.
O good roads Russians can only dream or build them under contracts life cycle so that the contractor himself maintains the constructed road and pays fines in case of poor laying.
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