Types of work on the maintenance of local roads
(text of the document with amendments and additions for November 2014)
Approved by
Order of the Ministry
The classification of the maintenance and repair of urban roads, the rules for the maintenance and repair of various coatings are given. Are given specifications used in the repair of machinery and mechanisms. Safety rules for roadwork are outlined.
The following took part in the development of the Technical Rules: Department of Urban Transport and Roads of the AKH named after K.D. Pamfilova, Rostov Research Institute of AKH, Scientific Researcher and design technol. Institute of Urban Management of the Ministry of Housing and Public Utilities of the Ukrainian SSR, General Directorate road facilities and beautification of Moscow.
1. CLASSIFICATION OF WORKS ON THE MAINTENANCE AND REPAIR OF URBAN ROADS
1.1. a common part
1.1.1. Maintenance and repair of city roads and sidewalks should ensure uninterrupted, convenient and safe movement of vehicles and pedestrians at any time of the year, ensuring the maximum increase in service life pavement at minimal cost.
1.1.2. Main challenge road organizationsresponsible for the maintenance and repair of urban pavements are the preservation of their transport and operational characteristics, timely identification and elimination of damage and deformations, as well as the implementation of a set of preventive measures aimed at preventing the appearance of deformations.
1.2. Nomenclature of maintenance and repair work
1.2.1. Maintenance and repair of urban roads are divided into the following types: maintenance, current repair, average repair and overhaul.
1.2.3. Maintenance includes the prevention of road damage and the repair of minor damage.
1.2.4. The average repair includes works on periodic compensation of the wear layer of the road surface, ensuring, if necessary, its sufficient roughness and the elimination of all damage to the road and road structures.
1.2.5. Overhaul includes work on the restoration of clothes of the carriageway of roads and sidewalks, as well as work related to the replacement of individual structural layers and elements of urban roads.
1.3. Scope of maintenance and repair of city roads
1.3.1. The maintenance of urban roads include:
a) maintenance of heaving sections of roads;
b) maintenance of drainage facilities;
c) dust removal of coatings of transitional and lower types (pavement of cobblestone, gravel, gravel, crushed stone, slag);
d) periodic monitoring of traffic intensity along highways and streets.
1.3.2. Depending on the types of damage, the routine maintenance of city roads includes:
a) sealing of potholes, subsidence and small breaks with small (up to 3 m2) and medium (3 - 25 m2) cards;
b) elimination of waves and influxes;
c) sealing cracks and joints;
g) surface treatment of the coating with a scope of work up to 300 m2;
e) profiling with sealing potholes and picking of individual sections;
f) restoration of coatings after tearing on carriageways of streets and sidewalks;
g) correction of drains;
h) the elimination of certain damages and subsidence of sidewalks with coverings of all types with cards up to 50 m2;
i) correction and replacement of individual side stones in areas with a total length of up to 100 m.
1.3.3. Work on the current repair of storm sewers includes the repair of water intake and inspection wells, the replacement of covers and gratings for manholes, and the extension of the mouths of wells.
1.3.4. The average repair of the carriageway of urban roads and storm sewers include:
a) correction of subsidence and breaks with large cards (over 25 m2) with simultaneous repair (if necessary) of the base and subgrade with the area of \u200b\u200bplaces to be repaired, more than 200 m2;
b) surface treatment of coatings with a workload of more than 300 m2;
c) the elimination of certain damages and subsidence of sidewalks with coverings of all types with cards of more than 50 m2;
d) correction and replacement of individual side stones in areas with a total length of more than 100 m;
d) liquidation of abysses on the carriageway of roads and sidewalks;
f) repairing damage and replacing worn-out pipes of drains, trays and arches;
g) replacement of brick inspection and rainwater gutter wells with reinforced concrete;
h) the replacement of the hatch and frame with the extension of the necks of the inspection and rainwater drainage wells.
1.3.5. The main types of deformations of road surfaces and side stones, the causes of their occurrence and methods of elimination are given in table. 1.
Table 1
The main types, causes and methods of eliminating deformations of pavings
Type of coating and type of deformation Main causes of deformation Methods for eliminating deformation 1 2 3
Asphalt concrete coatings
Long-term exposure to transport wheels and natural factors (normal wear), poor coating quality, high bitumen aging rate (premature wear)
The device layer of wear by surface treatment or build-up of a coating with a thin layer of asphalt
a) forming a grid
Instability of the pavement base and underlying soils, mismatch of the pavement design with traffic intensity and loads, increased viscosity and brittleness of bitumen contained in asphalt concrete
Elimination of the causes of waterlogging of the subgrade, instability of the foundation of pavement; in some areas, reinforcement of pavement and continuous construction of a new coating (recent work relates to overhaul)
b) curved shape
Increasing the viscosity and brittleness of bitumen contained in asphalt concrete (aging bitumen), sharp temperature fluctuations in winter conditions
Crack sealing with bitumen or bituminous mastic with powder stone fines
c) rectilinear outlines directed parallel and perpendicular to the axis of the road
Tensile forces acting in places of temperature and working joints of cement concrete bases and in places of transverse and longitudinal joints of asphalt concrete pavement during its construction
a) with the formation of flows and waves
Insufficient shear stability and increased plasticity of asphalt concrete, which is manifested in the hot season in places of braking of vehicles (at approaches to stopping points, descents, etc.)
b) with the formation of gaps in the coating
Inadequate adhesion between coating layers or between coating and base
Replacement of a deformed asphalt concrete layer with a new one from a shear-resistant mixture, heating of a deformed coating with the addition of a new shear-resistant mixture, cut-off
Pitting, peeling
The effect of moisture on a coating made of mixtures of increased porosity (lack of bitumen in the mixture, under-compaction of the mixture). Poor bitumen adhesion to the surface of stone materials
Sealing potholes followed by a wear layer
a) on the roadway
Loss of bearing capacity of the base due to waterlogging of the soil or heaving. Subgrade failures caused by an underground structure accident
Elimination of the causes of breaks, with the correction of the foundation of pavement and the installation of a new coating
b) in the area of \u200b\u200bthe tramway
Vibration and deformation of the tramway
Replacing asphalt concrete pavement in the area of \u200b\u200bthe tram track with a new asphalt concrete pavement from piece materials
Drawdowns:
a) gently sloping indefinite form
Insufficient compaction of pavement and roadbed, waterlogging of the roadbed, heterogeneity and mismatch of materials, mismatch of design with current loads
Close-up of drawdowns with correction (or without it) of the foundation of pavement, depending on the depth of drawdown and its area. In the event of overmoistening of the underlying soil, the elimination of the causes that cause it
b) longitudinal and transverse rectangular
Poor sealing of excavations during repairs or laying of underground structures
Close-up of drawdowns with correction of pavement base
Dents (marks)
The impact on the surface in the summer of protruding parts, metal tracks and rims with increased plasticity of asphalt concrete
Surface treatment
Bridge made of cobblestone and chipped stone:
Drawdowns:
a) local indefinite shape, gauge, distortion profile
The decrease in the strength of the soil base due to its overmoistening
Dismantling the pavement, replacing sand to the depth of the contaminated layer, restoring the pavement to ensure surface water drainage
b) rectangular
Poor gapping
Uneven abrasion of paving stones
Use of stone from weak breeds
Replacing worn stones
Gravel gravel and slag coatings
Potholes, lateral undulation (comb), rut
Base and coating instability
Coating pickling, adding new stone material, profiling and rolling coating
Concrete Coatings
Surface deformations (mortar spalling, peeling of the coating surface, formation of shells and delamination)
Poor quality of materials used, violation of the technology of preparation and placement of mixtures, poor maintenance of freshly laid concrete
Repair of coatings with cement-sand concrete using cement mortar or cement-colloidal adhesive, surface treatment of coatings with plastic-concrete or bitumen-mineral mixtures
a) surface
Inadmissible temperature stresses in concrete and dynamic impact of vehicles
Surface treatment using epoxy as a binder, cracking
b) through
Rupture of coatings from compression at low temperatures and a large distance between the seams. Insufficient thickness of the underlying sand layer and deformation of the subgrade
Repair using cement-concrete mixtures and mortars after partial cutting of concrete along the crack to a depth of 3 - 10 cm or after cutting concrete to the full thickness of clothes
Mismatch in terms of laying the seam and the groove of the seam cut in the upper part of the coating. Deviation of the seam pins from the horizontal, insufficient structural stability of the seam frame and poor pin retention in them. Concrete plugs under the expansion joint, between the gasket and the rail
Cleaning the seam, installing and securing the board to the gasket, repairing clothing areas adjacent to the seam, removing the board after concrete has set sufficient strength, priming the seam walls with bitumen and filling the seam with mastic or gasket
Destruction of the edges of welds and cracks with the formation of potholes
-
Repair using cement concrete mixtures and mortars
Vertical movements, deflections, buckling plates
Weak bases subject to changes in humidity and temperature
Correction and strengthening of the base with subsequent laying of plates
Drawdowns and plate breaks
The tendency of underlying soils to heaving, insufficient surface drainage
Correction of the bases, installation of drains, re-laying of the top layer
Side stone
Drawdowns, deviation from vertical
Impacts on the line of side stones, weak base (from crushed stone, without lateral stops)
Base repair with installation of stone at the mark
Chipped faces and corners, cracks, damage to the front surface
Insufficient frost resistance of concrete, low strength
Correction, rearrangement of stones, replacement with new stones
1.3.6. The volume of work on the repair of urban roads is assigned in accordance with the "Standards of annual volumes and the methodology for selecting and calculating the need for mechanization tools for work on the current, secondary and overhaul of pavement in the cities of the RSFSR of various categories" (MZHKH RSFSR, M., ONTI AKH, 1974).
1.3.7. Road-building materials used in the maintenance and repair of urban roads must meet the requirements normative documents (GOST, SNiP, etc.).
2.1. a common part
2.1.1. The maintenance of urban roads is carried out continuously throughout the year.
Depending on the period of the year, the following work must be carried out:
a) in summer: sweeping, watering and washing streets, sprinkling with mineral material coatings of lightweight and transitional types in places where bitumen comes to the surface ("sweating"), dust removal of paving of transitional and lower types;
b) in the fall: sweeping, washing, cleaning the streets of snow and dirt, preparing drainage facilities for winter, fighting ice;
c) in winter: cleaning streets and roads from snow and ice, combating icy conditions, caring for heaving sections of roads, ensuring water flow during winter thaws;
d) in the spring: ensuring the flow of surface water from the carriageway of roads and sidewalks, cleaning the streets of dirt, caring for heaving sections of roads.
Year-round care should be taken of drainage facilities.
2.1.2. Road sections, the subgrade of which is subject to abyss formation, should be taken into account and be under tight surveillance. Before the autumn rains, all repair work must be completed on them, and the drainage facilities and drains should be brought into good condition.
In winter time (especially in the first half of the winter period), the heaving areas must be cleared of snow to ensure quick freezing of soils at the same speed.
In spring, before the melting, the roadway and sidewalks in these sections of the streets should be completely cleared of snow and ice.
When detecting abyss formation, the following measures must be taken: strictly regulate traffic, limit the speed of movement of vehicles, close the movement for heavy vehicles, allowing only the movement of passenger vehicles and emergency vehicles; if necessary, completely close the movement.
2.2.1. Storm water inlets should be cleaned in spring after passing melt water and in autumn before closing and warming. The rest of the time, cleaning should be done as needed.
2.2.2. Wells should be cleaned mechanically. It is allowed to clean deep wells manually in the absence of mechanization.
2.2.3. Wells are manually cleaned by two workers, one of whom is in the well, and the other is on the surface (receives loaded containers, loads garbage into cars).
2.2.4. Mechanized cleaning of storm water inlets is carried out using suction pumps, for example, IL-980A.
2.2.5. Two workers clean the wells and chambers using the suction pump, one of which opens and closes the covers of the wells, and the other controls the suction nozzle of the suction pump.
2.2.6. In the absence of sludges, deposits can be removed using a watering machine. In this case, the cleaning is carried out using a water stream directed under high pressure into the well. The jet erodes deposits, which, together with water, are washed off into the drainage network.
To perform this work, the machine must be equipped with a long hose with a metal tip. Wells are washed from the surface.
2.2.7. Gutters with a diameter of up to 300 mm are cleaned once a year after the spring flood to prepare for the passage of summer storm water.
2.2.8. Pipes are cleaned with tap water from the hydrant using a long hose with a hose-type tip or using water-jetting machines and machines for cleaning storm water pipes, for example KO-502.
2.2.9. They begin to clean from the inspection well, located on the main collector, in the direction of the storm water inlet, so that sediments eroded by water are carried along with the flow of water along the slope into the main collector.
2.2.10. With absence technical means to clean pipes hydraulically using the puncture method using metal rods assembled from links 1 m long each. The rod is collected in the inspection well and with its help a cable is pulled with a ruff, which eliminates the blockage in the pipeline.
2.2.11. Gutters with a diameter of 400 - 1200 mm are cleaned once every 2 to 3 years. If there is water backwater, the elimination of the blockage begins with pumping water before the dam to avoid a possible breakthrough of water, and then eliminate the blockage in accordance with the requirements of paragraphs. 2.10 and 2.11.
2.2.12. Through and semi-bore collectors are cleaned in winter period.
2.2.13. Large collectors with a diameter of 1,500 mm or more should be cleaned as they become clogged, but not less than 4 to 5 years later.
2.2.14. Collectors begin to be cleaned from areas that have the lowest water flow rate, since the largest amount of deposits accumulate in these places.
2.2.15. Cleaning of bushing and semi-bore collectors is performed by hydraulic, mechanical and hydromechanical methods.
2.2.16. With the hydraulic method of cleaning the collectors, the work is performed in accordance with paragraphs. 2.10 and 2.11.
2.2.17. Collectors are mechanically cleaned by scraper plants, for example, OK-10, through inspection wells or chambers. The length of one section of work is equal to the distance between adjacent wells. The size of the scraper bucket is set in accordance with the cross section of the inspection well. Work begins with the upper part of the collector, moving sediments with scraper buckets towards the lower well, where they are removed to the surface by a suction pump or other means.
Scraper installations cannot be used on curved sections of collectors.
2.2.18. Hydromechanical cleaning is carried out using hydromonitors. The hydraulic monitor is located directly in the collector and a powerful jet of water erodes sediments, which are carried down the slope with the stream.
Through a lower inspection well, sediments of large fractions are removed to the surface by an ilososome or other method. Suspended fractions in suspension are carried away with the flow into the open channel.
2.2.19. To prevent freezing of the drainage network, the wells are insulated with metal sheets of old roofing iron. The sheets are placed under the storm water inlets, and the protruding edges of the sheet are pressed between the grate and the frame of the well. Metal sheets should have openings in the amount of 20 - 30% of the working area of \u200b\u200bthe inlet grate for passing surface water.
2.2.20. In winter, it is necessary to monitor the cleanliness of the rain gates so that they can freely receive melt water.
2.2.21. Thermal insulation is removed in the spring, starting from wells located in low places, and from those that have a large influx of water under the conditions of the relief. With a stable positive ambient temperature without night frosts, insulation must be removed completely from all wells.
2.2.22. Eliminate ice plugs in the drainage network by steam heating using mobile boilers, steam generators, for example D-163B. Steam heating of the storm water inlets is performed from above, and as the ice melts, the formed water is removed from the well.
Steam heating of the drainage network is carried out through the inspection well in the direction of the storm water well.
2.2.23. Measures for the passage of spring flood waters should begin with an assessment of the snow accumulated in urban areas, its reserves, degree of compaction, and pollution. In addition, you must have information about the weather forecast for the pre-flood period.
2.2.24. By the beginning of the flood water passage, trays on the streets, storm water inlets, all overflow pipes, ditches and underpasses should be cleared of ice and debris and, if necessary, dredging should be carried out.
2.2.25. For the period of the passage of flood waters, brigades of workers should be created, which, under the supervision of the master, should conduct round-the-clock monitoring of water passage and the state of the drainage network. The team must be fully provided with tools, mechanisms, transport.
2.2.26. After skipping the spring flood, the drainage network should be examined to detect damage.
2.3. Dust removal of coatings of transitional and lower types
2.3.1. Coatings of transitional and lower types dedust with organic and inorganic binders. Dust removal of pavement with organic materials is prohibited.
2.3.2. Inorganic dedusting agents include calcium chloride, soda waste containing calcium chloride, or other solutions containing hygroscopic salts.
Organic dedusting agents include liquid bitumen of grades SG-15/25, SG-25/40, MG-25/40, bitumen emulsions (GOST 18659-73), sulphide-alcohol bard (sbb), sulphite-yeast mash (sdb) and emulsions based on them, oil, fuel oil and waste oils.
2.3.3. Immediately before dust removal, profiling of the coating is carried out using a grader (with a significant amount of dust) or mechanical brushes.
2.3.4. Dust removal with a 20-30% solution of calcium chloride is carried out using water washers or tankers equipped with switchgears from the calculation of 1.5 - 4 l / m2 at the first (in two doses with a break between them from 2 to 6 hours) and 1 - 2.5 l / m2 at the subsequent ones. The period of dust removal action of calcium chloride after the first treatment is 3 to 5 weeks, and after subsequent treatments - 5 to 7 weeks.
Dust removal of black coatings with calcium chloride is prohibited.
2.3.5. Dust removal of coatings with liquid bitumen is performed 2–3 times a season: the first time at the beginning of the season, the subsequent ones during the season. Liquid bitumen is poured in a condition heated up to a temperature of 40 - 60 ° C by an asphalt distributor in dry, warm weather, when the coating is more heated by the sun. The norm of the first liquid bitumen for gravel, crushed stone and slag coatings is 0.3 - 1.25 l / m2. With repeated use, the binder is reduced by 30%. After the binder with sandblasting agent, coarse-grained sand is scattered over 3-4 passes. Sanding density up to 0.2 - 0.4 m3 of sand per 100 m2 of surface.
The movement on the road is opened after the binder is absorbed into the coating.
2.3.6. For dedusting of coatings with bitumen emulsions, medium or slow-decaying emulsions of the direct type are used with a content of 30-40% of bitumen of the BND-200/300, BND-130/200 or more viscous bitumen types in a diluted form. Dust removal with a bitumen emulsion can be performed in cool weather at an air temperature of no higher than +20 ° C with a wet coating, but not during rain. The technology of work consists of the following operations:
a) filling the emulsion with an asphalt distributor in an amount of 1.2 - 1.5 l / m2 at one time or with large dust formation - 1.5 - 2 l / m2 in two stages with intervals between them from 1 to 3 hours;
b) placer of coarse sand in an amount of 0.2 - 0.4 m3 per 100 m2 of surface;
c) compaction with two or three passes of the light roller (weighing 2 to 3 tons).
The traffic is allowed after the decay of the bitumen emulsion.
The frequency of repeated dedusting depends on climatic conditions and traffic intensity. Typically, dust removal work is performed 2 to 3 times a season.
2.3.7. Dust removal of coatings with sbb and sdb solutions is carried out using asphalt distributors in one step at a material flow rate of 1 - 1.5 l / m2 and in two doses at a flow rate of 1.5 - 2 l / m2.
2.4. Accounting for urban traffic
2.4.1. The intensity of road transport in cities is determined by direct observation or using automatic meters. To carry out the registration of traffic in the city, create reference checkpoints located in places agreed with the State traffic inspectorate.
The composition and intensity of traffic are taken into account at strong points in various parts of the city at least twice a month by the hours of the day. At the same time, the number of passing cars separately by type of vehicle is taken into account. For each reference point, an account card is written indicating the number of the registration point, the street on which it is located, the date of observation, the start and end time of the observations, the number of cars passed by type and load capacity in various directions included in the street node under consideration, as well as the name accountants. The form of the account card is given in Appendix. 1.
Records from accounting cards are transferred to the journal of the accounting point. At the end of a quarter or year, the average daily traffic intensity for the year, maximum and minimum traffic intensity, peak hours and traffic intensity at these hours, as well as the percentage of all types of vehicles of various types in the traffic flow are established in the journal. The form of the accounting journal is given in Appendix. 2.
At the same time, taking into account the movement of road transport at strong points, in agreement with the State traffic inspectorate, pedestrian traffic is recorded.
2.4.2. A passport is drawn up for each street, in which data on the state of individual elements of the street are entered in special forms. The passport is drawn up by the construction organization before the building is commissioned and, together with the executive documentation, is transferred to the road maintenance organization. For facilities in operation, the passport is the organization under whose jurisdiction they are.
The road passport contains the name of the object, the category of street and road according to the operational classification, year of construction, all basic dimensions of the elements, volume and value indicators, clothing design, drainage system, information about underground facilities and others. The passport records information about deformations and wear, repair, assessment of the general condition of the structure.
The passport form is given in Appendix. 3.
2.4.3. In the spring, after the snow melts, they inspect the carriageway of roads, sidewalks, drains and other structures of city streets in order to identify defects that have appeared during their winter operation. The inspection log form is given in Appendix 4.
Identified defects and damage must be repaired within 2 to 4 weeks after the onset of warm weather. In the future, they are eliminated as they appear. In the fall, 3-4 weeks before inclement weather, the roads should be inspected and repaired again to prepare them for use in winter conditions.
3. CURRENT REPAIR OF URBAN ROADS
3.1. Repair of asphalt concrete pavements
Sealing potholes and subsidence.
3.1.1. Hot, warm and cold asphalt mixtures that meet the requirements of GOST 9128-76 are used to seal potholes, subsidence and breaks. Mixtures should be of the same type and composition from which the coating was built. When sealing deep potholes, when repairing not only the upper, but also the lower coating layer, it is allowed to lay the mixture prepared for the upper layer to the full depth. Sandy asphalt concrete may be used for the upper and lower layers only with potholes up to 1 m2; with potholes larger than 1 m2, sand asphalt can only be laid in the upper layer.
3.1.2. Repair of asphalt concrete coatings using hot mixtures is performed in the dry season at air temperature not lower than plus 5 ° C, warm - not lower than 0, cold and emulsion-mineral mixtures - not lower than minus 10 ° C. Deformations that arose during the winter operation of roads, in order to prevent their development during the spring thaw, should be corrected in winter conditions before the spring thaw. In this case, it is allowed to use cold asphalt mixture to seal potholes on coatings constructed from hot mixes.
To repair coatings in wet weather conditions, it is recommended to use mixtures with additives of surface-active substances (surfactants) or emulsion-mineral mixtures.
3.1.3. Anionic surfactants of the type of higher carboxylic acids (gossypol resin, distillation residues of synthetic fatty acids, cotton tar, second fatty acid tar, etc.) and the type of iron salts (soaps) of higher carboxylic acids are added to the asphalt mixtures containing mineral materials of the main rocks, and 3 - 5% of the weight of bitumen; cationic surfactants of the type of tetra-substituted ammonium bases (catapines A and K, etc.) are added to mixtures containing acidic rock mineral materials in an amount of 0.5 - 2% of the weight of bitumen; cationic surfactants of the type of aliphatic amines (amine, diamine, BP-2, BP-3, etc.) in the amount of 0.5 - 2% of the weight of bitumen are added to mixtures containing mineral materials of both acidic and basic rocks.
3.1.4. Repair of coatings using materials on bitumen emulsions is carried out at positive air temperatures and is completed three weeks before the onset of frost. It is allowed to carry out work on wet surfaces, but in the absence of puddles in the repaired area. The materials are used cold.
3.1.5. For repair work, direct anionic or cationic bitumen emulsions are used, which belong to the classes of fast-, medium- or slow-decaying. The scope of these emulsions is given in table. 2. Bitumen emulsions must meet the requirements of GOST 18659-73, and emulsion-mnemonic mixtures must meet the requirements of the "Temporary technical guidelines for the use of bitumen emulsions in the construction and repair of road pavement in populated areas" (MZHKH RSFSR, Rostov-on-Don, 1972).
table 2
Field of application of emulsions
Types of work Emulsion class fast decaying medium decaying slowly decaying
Preparation of emulsion-mineral mixtures with a particle content of less than 0.071 mm more than 5%
- - +
- + +
Impregnation of crushed stone materials
+ + -
Processing of the bottom and edges of felling (sizing)
+ - -
Surface treatment device
+ + -
Dedusting
- + +
3.1.6. Work on sealing potholes and subsidence is performed in one of the following ways:
a) cutting down and removing material on the damaged section of the road surface;
b) heating the asphalt concrete of the repaired coating area.
3.1.7. Repair with cutting down the material of asphalt concrete coating includes the following technological operations:
a) cleaning the surface of the repaired area from dust and dirt with mechanical brushes and compressed air;
b) marking the boundaries of potholes;
c) cutting down the contoured material of the coating with its removal from the repaired place;
d) processing the walls and bottom of the felling with a thin layer of bitumen;
d) layout asphalt mix to the place being repaired;
e) compaction of asphalt concrete;
g) smoothing the interface between the new asphalt concrete and the old coating.
3.1.8. The boundaries of potholes and other damages are marked with chalk in straight lines parallel and perpendicular to the axis of the road, with a 3–5 cm capture of the undamaged pavement. Potholes that are closely spaced from each other are combined into one common map.
Failure of damaged asphalt concrete pavement is carried out using pneumatic or electric hammers. Asphalt concrete is cut down to the depth of the pothole, but not less than the thickness of the upper layer of the coating. The edges of the felling should be vertical.
Felled material is removed from the work site.
3.1.9. After thoroughly cleaning the felling from small pieces of asphalt concrete and dust with compressed air, its bottom and edges are treated with liquid bitumen or bitumen emulsion. Processing is carried out with the help of mobile small capacity tarmacs (for example, D-125A or special sprayers included in the set of equipment for car repairmen).
For processing using liquid bitumen grades MG-25/40, SG-15/25, SG-25/40; liquefied viscous bitumen of grades BND-90/130, BND-130/200 and BND-200/300, heated to a temperature of 80 - 100 ° C at the rate of 0.5 - 0.6 l / m2, as well as direct bitumen emulsion related to the class of rapidly decaying, with a concentration of bitumen of 50 - 60% in an amount of 0.6 - 0.9 l / m2.
3.1.10. The delivery of asphalt concrete mixture to the workplace is carried out in hoppers-thermoses of car repairmen or in light-duty dump trucks. The distribution of the mixture is carried out manually.
3.1.11. The minimum allowable temperature of the mixture during installation, depending on the grade of bitumen, must comply with the requirements of table. 3.
Table 3
The minimum allowable temperature of the mixture during installation (from GOST 9128-76)
Types of mix Bitumen grade Mix temperature, ° C when discharged from the mixer in an asphalt paver when laying in a structural layer, not lower than without surfactant with surfactant without surfactant with surfactant
1. Hot
140 - 160 120 - 140 120 100
110 - 130 100 - 120 80 80
80 - 100 80 - 100 70 70
80 - 100 80 - 100 70 70
3. Cold
90 - 110 80 - 100 Not lower than + 5 ° in the spring
90 - 120 80 - 100 Not lower than + 10 ° in the fall
Note. When constructive layers of pavement are provided low temperatures in case of using viscous bitumen, mixtures with a temperature of 10 ° C higher than indicated in the table are allowed.
3.1.12. Hot, warm and cold asphalt or emulsion-mineral mixtures are laid in one or two layers, depending on the depth of the pothole. When sealing deep potholes, when not only the upper, but also the lower coating layer is cut, the mixture should be laid with a layer-by-layer seal with a layer thickness of not more than 5 cm.
To ensure evenness of the repaired coating, the mixtures are stacked taking into account changes in the layer thickness during compaction: the layer of hot and warm mixture should be 25 - 30%, and the layer of cold asphalt concrete and emulsion-mineral mixture should be 50 - 70% more than the thickness of the layer being repaired. When using cold asphalt concrete and emulsion-mineral mixtures, the surface of the repaired places should be 10 - 15% of the total thickness of the layers of the laid mixture above the surface of the existing coating, taking into account that the final compaction will be achieved under the influence of moving transport.
The estimated need for materials for sealing potholes and subsidence per 1 m2 of coverage with cutting down old asphalt concrete is given in Table. 4.
Table 4
Estimated amount of materials required to seal potholes and subsidence per 1 m2 of coverage
Layer thickness, mm Asphalt-concrete mixture, kg Emulsion-mineral mixture, kg For priming, kg Sandy or fine-grained (upper layer) Medium or coarse-grained (lower layer) Fine-grained (upper layer) Medium-grained (lower layer) Bitumen emulsion 30 70 - 66 - 0.5 - 0.55 0.6 - 0.8 40 93 - 83 - 0.5 - 0.55 0.6 - 0.8 50 116 - 110 - 0.5 - 0.55 0.6 - 0.8 60 70 72 66 68 0.55 - 0.6 0.7 - 0.9 70 93 72 88 68 0.55 - 0.6 0.7 - 0.9
3.1.13. Repair of asphalt concrete pavements by the method of heating with asphalt heaters with infrared burners (for example, AR-53 and AR-63A) includes the following technological operations:
b) heating the asphalt concrete coating with infrared burners;
c) loosening of heated asphalt concrete manually;
d) laying and leveling fresh asphalt mix;
e) sealing of the coating.
3.1.14. The burner block of the asphalt heater is installed above the place to be repaired so that there is a distance of 12-15 cm between the coating and the surface of the emitter, the burners are lit, and after heating the emitters for 40-50 s, the asphalt concrete coating is heated. The limiting temperature of coating heating (130 - 150 ° C) is determined visually by the appearance of blue smoke above the surface of asphalt concrete, which indicates the beginning of binder burning. If the binder on the heated surface begins to burn out, and the coating is warmed up to an insufficient depth, further heating of the asphalt concrete is carried out by lifting the burner block to a high height. Asphalt concrete heating time - 3-5 minutes, depending on the air temperature.
3.1.15. After warming up, the coating is loosened and the required amount of fresh asphalt mix is \u200b\u200bfed through the tray of the thermos hopper to the place to be repaired (Table 5). The unloaded mixture is leveled, partially mixed with old pre-heated asphalt concrete and compacted.
Table 5
Amount of added asphalt mixture per 1 m2 of coating during repair with heating, kg
Layer thickness, mm Percentage of damage to the coating 20 30 40 50 60 70 30 13 13 26 26 39 39 46 40 18 26 35 44 53 62 50 22 33 44 55 66 77 60 26 39 52 65 78 91 70 30 45 60 75 90 105
3.1.17. Asphalt during repair of the coating by cutting down and heating the old asphalt concrete is compacted with self-propelled rollers with smooth rollers weighing 5-10 tons, self-propelled or manual vibratory rollers, mechanical, and with small volumes of work - with manual rammers. Seals lead from the edges of the repaired place to the middle. The number of passes of the roller with smooth rollers on one track should be 8 - 12 for compaction of hot and warm mixtures and 6 - 8 for compaction of cold mixtures. The compaction factor must be at least 0.96.
3.1.18. The compaction of coatings from a hot asphalt mix must begin at the highest possible temperature at which no hair cracks form. Such temperatures are: for mixtures of multi-grained - 140 - 160 ° C, medium-grained - 120 - 140 ° C, small-grained - 100 - 130 ° C, sand from crushed sand - 130 - 140 ° C, sand from natural sand - 90 - 120 ° C.
In all cases, one should strive to complete the compaction of the mixture as soon as possible at its highest possible temperature. The extremes below which sealing is ineffective are temperatures: for hot mixtures prepared on bitumen of the BND-40/60 brand, - 70 - 80 ° C, on the bitumen of the BND-60/90 and BND-90/130 - 60 - 70 ° grades C, for warm mixtures prepared on bitumen grade BND-130/200, - 50 - 60 ° C, on bitumen grade BND-200/300 - 40 - 60 ° C and on bitumen grade SG-130/200 - 35 - 40 ° C.
3.1.19. The junctions between the new asphalt concrete and the old are smoothed with hot metal irons.
The traffic on the repaired section of the road is opened after cooling the asphalt mixture to a temperature of 20 - 30 ° C. In the case of using an emulsion-mineral mixture for repair work, the repaired place is sprinkled with dry sand or seedlings. Traffic on the road section is opened after 8 - 16 hours after repair. During the first 2 to 3 days, the speed is limited to 30 km / h.
Elimination of waves and influxes.
3.1.20. Waves and flows generated on asphalt concrete pavement are eliminated by cutting, cutting or warming up.
3.1.21. Aligning the asphalt concrete pavement with the method of cutting waves and sagging includes the following technological operations:
a) cleaning the surface of the repaired area from dust and dirt with mechanical brushes;
b) heating the coating;
c) cutting of waves and influxes.
Asphalt concrete coating is heated with asphalt heaters (for example, AP-53 or AP-53A). Wave and influx are cut by a grader (for example, D-144A). With small volumes of work and a small height of waves and influxes (up to 5 cm), they can be cut manually.
3.1.22. Waves and flows on asphalt concrete pavements are eliminated by cutting or heating with removal of old asphalt concrete to the bottom layer of the coating or to the base when the height of the flows and waves is more than 5 cm.
Deformed asphalt concrete is removed and replaced with shear-resistant. For repair of coatings subject to shear deformations, it is recommended to use multi-grained and medium-grained (types A and B according to GOST 9128-76) frame mixtures or mixtures with the addition of short-fiber asbestos (1 - 1.5% of the weight of the mineral part). Sealing prepared places is performed in accordance with the requirements of paragraphs. 3.1.6 - 3.1.15.
Sealing cracks.
Cracks on asphalt pavement close in the spring, autumn or summer in the morning, in cool, dry weather, when the cracks are most open.
3.1.23. Crack repair work includes the following technological operations:
a) cleaning cracks from dust and dirt with steel brushes, metal hooks, as well as blowing with compressed air from the compressor;
b) filling cracks with liquid bitumen of grades SG-70/130, SG-130/200, MG-70/130 and MG-130/200; liquefied bitumen obtained by mixing viscous bitumen grade BND-250/300 or BND-130/200 with kerosene, or special mastic. The compositions of the mastics, taking into account their use in various climatic zones, are given in table. 6;
c) dusting of cracks filled with bitumen with dry stone fines (0 - 5 mm) or coarse-grained sand (when using mastics, sanding is not performed).
Table 6
Mastic compositions
Components,% by weight Road climatic zones II - IV II - IV III - V II II - III III - I Softening point of mastics, ° C 60 - 65 60 - 65 75 - 85 55 58 65
Bitumen grade BND-90/130 or BND-60/90
60 60 60 80 70 50
Mineral powder
25 25 20 10 25 35
Rubber crumb
5 - - 10 5 5
Short-fiber asbestos
10 15 20 - - 10
Before use, liquid and liquefied bitumen are heated to 80-100 ° C, and mastics are heated up to 150-170 ° C before flowing out of the outlet.
3.1.24. Crack repair works are performed using special machines, for example, ED-10, which allow hot bitumen or mastic to be fed under pressure. For small volumes of work, manual crack fillers, for example, D-344, can be used. In this case, bitumen flows to the crack by gravity, so an additional operation is introduced: after cleaning the cracks from dust and dirt, they are smeared with MG-25/40 or SG-15/25 liquid bitumen with a hard brush, and then filled with bitumen or bitumen mastic.
3.1.25. Wide cracks with destroyed edges are closed by the method of cutting asphalt concrete with a strip of 5 - 10 cm on each side of the crack to the thickness of the upper layer, and in the case of deep cracks - to the entire thickness of the asphalt concrete, or by heating burners with infrared radiation. In this case, instead of the main burner block of the asphalt heaters AR-53, burners can be used that are interlocked in a portable ruler, which is included in the machine equipment set.
Asphalt concrete is heated for 3-5 minutes, after which it is loosened to a depth of 1-1.5 cm at the edges of the heated strip and up to 3 cm at the edges of the crack. After removing dust and dirt and contaminated asphalt from the crack, fresh sand asphalt mix is \u200b\u200badded to the crack, the amount of which is selected taking into account its precipitation during compaction. After mixing the old and new asphalt mixes and leveling with trowels, it is compacted with a tamper.
Features of repair of asphalt concrete pavements on the sidewalks.
3.1.26. When repairing asphalt concrete pavements, sidewalks mainly carry out work to eliminate potholes, subsidence and breaks, as well as to repair cracks.
3.1.27. If the cause of the damage is the instability of the bases, then in the process of repairing the coating, the base is also repaired. Repair of sidewalks is carried out according to the same technical rules as repair of the carriageway of city roads. The difference is only in the used machines and mechanisms.
3.1.28. To seal potholes, subsidence and breaks on the sidewalks, as a rule, a sandy asphalt mixture of type G and D or cast asphalt concrete is used.
3.1.29. Pavement repair is carried out using the following machines and mechanisms: pavement harvesting machine, compressor with pneumatic tools for breaking damaged coatings, paving asphalt pavers for laying asphalt mixes, small-sized pavement rollers with static or vibration effects for compaction of asphalt mixes. To repair potholes on the sidewalks, the MTTRD auto repair shop can also be used.
3.1.30. For closing cracks, the same machines and tools are used as for the carriageway. In places where machines and mechanisms are not readily accessible for use (the presence of ledges of buildings, manholes, fences, poles, green spaces, etc.), small-scale mechanization means are used for repairs: electric or pneumatic tools.
3.1.31. The movement of pedestrians on the repaired section of the sidewalk is opened after complete cooling of the stacked and compacted mixture.
3.2. Repair of cement concrete coatings
3.2.1. Maintenance cement-concrete coatings includes the sealing of potholes, cracks, joints, broken edges at the joints, spalling of corners, regardless of the amount of work, as well as correcting subsidence and small breaks, straightening the position of individual plates without replacement, with an area of \u200b\u200bplaces to be repaired up to 200 m2.
3.2.2. Maintenance is carried out using cement concrete and cement-sand mixtures, plastic and polymer concrete, asphalt concrete and black crushed stone mixtures, ready-made concrete and reinforced concrete elements.
Sealing potholes and subsidence.
3.2.3. Repair work using cement concrete mixtures is performed at an ambient temperature of at least + 5 ° C. At lower temperatures, the work is performed in accordance with the rule of winter work. When using polymer mixtures, repair work is carried out at a temperature not lower than plus 15 ° C.
Repair work using asphalt concrete and black mixtures is performed at an ambient temperature of at least minus 5 ° C.
3.2.4. If the damage depth is more than 5 cm, sand concrete, cement concrete and asphalt concrete with a maximum crushed stone size of 20 mm should be used for repair. To repair small surface damage up to 5 cm deep, sand concrete should be used.
Repair of peeling up to 3 cm deep is carried out using epoxy glue and epoxy-mineral mixtures.
For urgent repair of damage in the form of chipped edges and corners of plates, shells and potholes with a depth of 5 to 15 cm, a width of 15 cm, it is recommended to use quick-hardening fine-grained concrete on liquid glass (GOST 13078-67).
3.2.5. Repair of cement concrete coatings includes the following technological operations:
a) preparation of the repaired surface;
b) surface treatment cement-sand mortar or colloidal glue;
c) sealing the mixture with surface finish;
d) care for freshly laid concrete.
3.2.6. Damaged areas are marked with straight lines (chalk or paint), then using a machine for cutting seams (for example, ДС-510 or a concrete saw) in a concrete, a groove is cut along the contour to the depth of destruction and the concrete is broken with a pneumatic or electric tool. If the dimensions of the damaged area coincide with the dimensions of the plates, they do not make cuts, and existing seams are used as grooves. The cut-down cement concrete is removed, the repaired place is thoroughly cleaned of concrete fragments and dust with metal brushes and blowing. After removing the old concrete, the repaired areas are watered.
3.2.7. Depending on the size of the stone material, which is part of the cement-concrete mixture, as well as the material used for priming the surface to be repaired, two repair methods are distinguished using:
a) cement-concrete mix for cement-sand mortar;
b) sand concrete mix on cement-colloidal glue.
3.2.8. When repairing with cement-concrete mixture, two layers are applied to the cleaned surface cement mortarprepared in a paddle stirrer forced action. The solution at the rate of 2–3 kg / m2, with a layer thickness of 1–2 mm, is evenly distributed over the repaired surface with hard hair brushes or paint brushes. To prepare the solution, Portland cement grade 500 or 600 (W / C \u003d 0.35), sand c. The solution should be a tough consistency of the composition 1: 1. The viability of the solution is 15 to 20 minutes.
3.2.9. After the disappearance of the aqueous film of the solution (loss of gloss), the concrete mixture is laid. The following cements should be used to prepare the concrete mixture: quick-hardening cement (BTC), especially quick-hardening cement (OBTC), expanding Portland cement (ROC) of grades 400-500, Portland cement of a grade not lower than 600.
SDB 0.1 - 0.15
Neutralized air-entraining resin
START 0.02 - 0.05
Ethyl Siliconate Sodium
GKZH-10 0.1 - 0.2
Sodium methylsiliconate
GKZH-11 0.1 - 0.2
Ethylpolyhydrosiloxane
GKZH-94 0.1 - 0.15
a) Portland cement grade 600 - 450 kg; stone fines of rocks of fraction 2 - 5 mm - 1000 - 1200 kg; sand with; water - 160 - 180 l; - 2%, surfactant in accordance with table. 7;
b) OBTC - 300 - 400 kg; ROC - 75 - 150 kg; granite or limestone crushed stone fractions of 5 - 10 mm - 1100 - 1200 kg; sand with; water - 190 - 200 l; triethanolamine additive - 0.1 - 0.2 kg; SDB - 0.1%.
3.2.10. The concrete mixture is laid manually above the level of the repaired coating by a value of 0.3 depth of felling. After laying, the mixture is compacted to a maximum density with a surface vibrator; on narrow and small cards, the compaction is performed by vibration or pneumatic rammers. Finishing is done with a vibrating rail, wooden trowel with rubber tape, trowels and graters. The flatness of the surface is checked with a three-meter rail. The clearance between the surface of the repaired coating and the rail should be no more than 3 mm.
A road service has been organized on the roads of the Soviet Union, the tasks of which are: to ensure the safety and convenience of vehicles with estimated speeds and loads throughout the year; ensuring the safety of roads and road structures; systematic monitoring of the nature of the movement of cars and taking measures to improve the technical condition of the road.
The road service is primarily responsible for eliminating the causes of any significant damage. Therefore, the road service must continuously keep the road and especially its carriageway clean, eliminate even small defects that violate traffic safety, monitor the evenness of the pavement and increase its strength with increasing traffic intensity. For traffic safety, it is very important to systematically maintain the roughness of the coating, first of all, restoring the wear layer at sharp turns and large slopes. Measures should be taken against snow drifts and icing of the road surface in winter. For better use of the roadway, it is necessary to monitor the condition of the roadsides and reinforcing strips along the edge of the roadway. The road service is responsible for the installation and maintenance of road signs, road markings and the installation of fences in the most dangerous places.
In addition, the content includes traffic metering, landscaping, technical metering, inventory, lighting and road safety.
The main types of work are carried out in a planned manner, depending on the condition of individual road structures.
Maintenance is a systematic work to repair minor damage to road structures (subgrade, road pavement, artificial structures). Depending on the season of the year, the nature of these works is different. Emerging damage defects should be immediately eliminated.
Medium repairs are carried out periodically in order to restore the operational qualities of the road and road structures.
With an average repair, the following main works are performed:
on subgrade and drainage - repair and strengthening of roadsides, slopes of the canvas and reserves, repair of drains, pipes, channels at bridges, etc .;
on road clothes - restoration of a layer of wear, leveling of a covering and increase of a roughness. Restoration of evenness of gravel, gravel and ground coatings the addition of new material, device turns;
on artificial structures, buildings and track conditions - simple repairs with the replacement of individual elements, the installation of new signs, the installation of fences, the improvement of interchanges of recreation areas, the construction of sidewalks.
Overhaul - works. Aimed at the full restoration of the operational qualities of the road and road structures.
At the same time, worn structures can be replaced with more durable and progressive ones.
At overhaul work envisaged:
on subgrade and drainage - restructuring of individual elements in order to increase strength and stability, the device of intersections at the same level;
on road clothes - thickening, broadening, the arrangement of new clothes;
on artificial structures, buildings and track conditions - rebuilding bridges to new ones, building galleries, retaining walls, tunnels, fortifications, building new buildings for operational services, arranging ramps and entrances up to 100 m long, signaling, lighting, architectural design, construction car pavilions, recreation places, etc.
Repair of advanced crushed stone and gravel coatings provides for: elimination of pits, cutting of tubercles and sagging, surface treatment, and with significant damage, continuous smoothing and thickening of coatings.
On asphalt concrete pavements, cracks, subsidence, shifts and flows, longitudinal waves, spalling, and edge destruction most often occur. To ensure the normal movement of vehicles, these defects must be timely eliminated by filling cracks, removing sagging, surface treatment; with significant damage, a new layer of asphalt concrete mix is \u200b\u200blaid.
Repair of cement concrete coatings consists in repairing cracks, repairing potholes, repairing and replacing slabs, and repairing joints. With significant chipping and peeling of the surface of the cement concrete coating, a surface treatment device or laying a layer of asphalt concrete is possible.
The fight against dust and dirt on the roads is essential in the process of road maintenance. Good adhesion to the pneumatic tires of a car is ensured by a dry and clean coating and largely depends on the roughness of its surface. If road surface has a large roughness, and the tire tread is made of an elastic material, the protruding small tubercles of hard and durable coating are pressed into the running surface of the tire and provide good adhesion of the wheels to the road.
If there is a layer of dust on a dry coating, the tire tread indentation is difficult and traction is slightly reduced. If dust and soil particles are wetted by water, i.e. a film of slippery dirt is formed, the adhesion coefficient is reduced by 2-3 times. In the absence of contact of the tire with the road, due to the large thickness of the slippery mud layer, the adhesion coefficient becomes the smallest, i.e., almost the same as during icing at temperatures above 0 ° C. If the lubricating mud film is completely extruded from the tire contact area and road surface, adhesion coefficient approaches the value corresponding to dry surface.
Significantly affects the state of contact of the tire with the road pressure exerted by the wheel of the car on the road. With a worn out tread, the pressure on the contact increases and the adhesion coefficient increases accordingly. The presence of roughness on the surface of the coating increases the pressure and contributes to the full extrusion of the mud film. Under this condition, despite contamination and humidity, the adhesion coefficient does not decrease.
When wet and dirty, the adhesion rate is affected by the vehicle speed. As the driving speed increases, the tire’s contact time with the road decreases and the extrusion of the mud film worsens.
According to tests, depending on the change in speed, the coefficient of adhesion, for example, asphalt pavement when wet and dry changes
Thus, to ensure traffic safety, even advanced coatings must always be kept clean and systematically cleaned of dust and dirt.
The most intense dust formation is observed at dirt roads and on roads with gravel and gravel surfaces. More wear resistant coatings dust less. The main source of dust on the road is the products of coating wear. Dust rises and forms a dust cloud above the road with the wind and swirling movements created by the cars. A dusty cloud limits visibility on the road, as a result of which it is necessary to increase the distance between moving cars and reduce speed. Dust increases wear of the rubbing parts of the car, impairs engine performance and adversely affects the driver and passengers. To combat dust, coatings are watered with water, a solution of hygroscopic salts (calcium chloride), organic binders (bitumen emulsions). Road service has special machines for cleaning dust from the roadbed, which have watering and washing devices.
For most regions of the USSR, road maintenance in winter is particularly difficult. Even if there is a loose snow cover on the coating with a thickness of 10 cm, the vehicle speed is significantly reduced, and with a loose snow cover thickness of 25 cm, only off-road vehicles with a reduced speed are possible. Under the action of moving cars, a layer of dense snow forms on the road, which, however, wears out and ruts, bumps, and potholes form on its surface, which complicate traffic conditions. The most difficult conditions are created when ice forms on the surface of the road. A slippery crust of ice, often having an uneven surface, violates traffic safety, causes a decrease in speed and, in addition, accelerates the wear of cars.
In accordance with modern requirements, roads with improved coatings should not have snow and ice crust; on roads with transitional and lower types of coatings, a layer of compacted snow is allowed with a thickness of not more than 8-10 cm. It is not allowed to leave uneven snow rolls with steep slopes on the curbs and beyond. When icing occurs, measures must be taken to combat slippery.
To protect the road from snow, various artificial snow-holding devices are used: portable shields, permanent fences, fences made of local materials. Often used portable shields. The action of these devices is based on reducing the speed of the snow-wind flow to such a value that precipitation of snow particles occurs and their deposition at the shield. The shield line is parallel to the axis of the road. Depending on the amount of snowfall in a given area, it should be installed at a distance of not less than 30 m from the road and not further than 60 m. In areas with strong and prolonged snowstorms, permanent fences are installed, since moving shields becomes difficult.
More reliable means of snow protection are protective plantings. The snow-holding hedge is a linear planting of trees and shrubs in several rows. A properly designed hedge completely delays the transported snow and, after many years of operation, is much more economical than portable shields.
The use of snow retention means does not preclude its deposition on the road during snowfall. To ensure uninterrupted movement of vehicles, the road must be cleared of snow in a timely manner. Deposits should be removed before the formation of a large layer of snow on the road. Even on roads with reliable means of snow protection, with snowstorms and snowfalls, cleaning starts immediately, as falling snow rolls in with wheels and ruts and bumps form on the roadway.
With the onset of snowfall, a snowplow starts, in which the snow is thrown to the side outside the clearance strip. For this, plow single-blade and double-blade automobile snowplows are used.
In case of very intense snowfall, when there is a rapid accumulation of snow on the roadbed and cars that work on cleaning cannot reach the required speed (25-30 km / h) for throwing snow, the snow is shifted from the carriageway, as a result of which snow form on the curbs shafts. Motor graders, bulldozers and other means can be used to move snow, and removing shafts is best done with auger-rotor snow blowers that throw snow 25-30 m from the road.
To ensure the safety of vehicles in the winter, it is necessary that the road surface is not slippery. With a strong compaction by the movement of the snow crust or icing of the road surface after thaws, the coefficient of tire friction against the surface sharply decreases (0.08-0.12), as a result of which traffic safety conditions are violated, especially on longitudinal slopes of more than 40-50% about; road intersections and curves of small radius. The speed of movement to avoid accidents on slippery roads is reduced. The most rational, but difficult to achieve measure against slippage is to completely clear the surface of snow. To increase the coefficient of friction of tires with the road scatter sand, ash, slag (abrasives) particle size of which is not more than 6 mm. The material is dispensed from specific dispensers thin layer.
It is more efficient to mix abrasive materials with calcium chloride or sodium chloride before scattering. In this case, the scattered material is embedded in the ice crust and is well kept on it. However, this method has its drawbacks. Salt has a harmful effect on cement concrete coatings, especially in the first three years after construction, so its use in this case is undesirable. Salt also increases the corrosion of metal parts of cars passing on the road.
To eliminate these disadvantages, various inhibitors are used that are introduced into the chlorides and reduce the degree of corrosion to a natural level.
Modern car roads constitute a complex engineering complex of structures designed to ensure the movement of road transport for any weather conditions. This engineering complex in addition to the subgrade and pavement includes bridges and pipes, protective road constructions and the construction of related services. It is the condition of all the components that determines the level of operational condition of the road.
What is necessary for the most efficient functioning of the road?
For the effective functioning of the road, it is necessary to constantly ensure not only traffic management, but also its proper technical exploitation, which includes both preventive and repair work.
Based on many years of experience, it can be argued that the economic return on road maintenance and maintenance exceeds the economic return on funds invested in road construction from scratch. It should be noted that new roads after commissioning also require constant maintenance and maintenance.
Climatic conditions
Indisputable influence on the condition of roads and the conditions of movement of motor vehicles on them have natural and climatic conditions. For Russia, given its vast territory and various climatic zones (from Antarctic to subtropical), this fact is of particular importance.
Today, the Russian road network is in such a state that the repair of existing roads is a more important task than the construction of new roads. One of the main tasks is to increase the capitality of pavements, which ensures both high speeds and traffic safety. The quality of pavement depends on the quality of work on asphalt. It should be noted that the use of asphalt chips, which is obtained as a result of recycling, can significantly reduce the cost of asphalt road works. asphalt pavement roads after removal by thorough and uniform grinding. The price of asphalt chips is significantly lower than the price of asphalt.
Asphalting modern roads requires step-by-step and accurate compliance technological process. Only in this setting does the asphalting of the road provide a reliable pavement having the appropriate operational properties. Depending on what functional load the road carries, asphalting is performed in one or two layers.
Asphalting roads is a laborious and expensive process that should only be trusted by professionals who are responsible and give a guarantee for every meter of paved asphalt. Qualified specialists and special equipment will provide pavement with high performance.
