Razumov Yu.V. Associate Professor of the Department of "Road Construction Machinery"

1. Distributors of anti-icing agents.

Anti-icing machines come with mechanical, physico-thermal and chemical methods of influencing ice. When maintaining road surfaces, mainly distributors of anti-icing materials with a chemical effect on ice are used, i.e. distributors on the surface of the coating of sand, chlorides, reagents, etc. The special equipment of these machines consists of a body for technological materials, a scraper conveyor, a switchgear, a drive and hydraulic systems. Distributors are often equipped with additional equipment: a brush device and a snow plow, the design of which is similar to that of sweepers.

The working equipment of the distributor is mounted on the basis of trucks (Fig. 2.9.). A special body-bunker of a welded structure with a volume of 2.2 ÷ 3.0 m3 is installed on the car. The side, front and sometimes rear walls of the body are angled to better move the sand down to the conveyor and on to the distributor. At the bottom of the body there is a scraper conveyor, the driven shaft and the tension mechanism of which are mounted in the front part of the body. The scraper conveyor is used to feed the material to the distribution device installed at the rear of the body. The rear wall of the machine has an opening for the exit of the scraper conveyor, from which the material enters the guide funnel. From the funnel, the de-icing material enters the distribution device, as a rule, of a disk type. The disc rotates at a frequency of 1.7÷8 rpm, and under the action of centrifugal forces, the material is fanned out over the coating. The width of the material distribution strip is 4÷8 m. The drive of the working equipment of the machine can be mechanical or hydraulic. In a mechanical drive, the torque is transmitted from the main automobile engine through the power take-off, cardan gears, chain and gear reducers to the drive shaft of the scraper conveyor, distribution disk and brush device.

In machines with a hydraulic drive, the torque from the car engine is transmitted to the hydraulic system, which drives the scraper conveyor and disc. The hydraulic drive provides the possibility of a smooth, stepless change in the speed of the scraper conveyor and the frequency of rotation of the distribution disk, which allows you to set the required density of distribution of materials (30÷500 g/m3) and the width of the coating without changing the speed of the vehicle. IN Lately liquid reagents are increasingly being used to combat ice. For the distribution of liquid anti-icing materials, watering and washing machines or special distributors can be used. The productivity of gritters is determined in the same way as self-propelled machines of continuous operation, taking into account losses for loading the body with anti-icing material, moving the machine in a loaded and unloaded state, and other auxiliary operations. Average performance machines for the distribution of anti-icing materials is 20÷90 thousand m/h. The use of gritters at airfields is highly undesirable. This is especially contraindicated at airfields where aircraft with turbojet engines are operated. The use of such machines at airports should be limited to access roads. To remove the ice film and snow-ice run-up formed on the surface of the coatings, heat engines are used. The principle of operation of heat engines is to influence the icy coating with the help of a high-temperature high-speed flow of combustion products of the air-fuel mixture coming from a turbojet engine mounted on a special vehicle frame. To increase the efficiency of the process of removing ice from the coating, a number of thermal machines install additional sources of infrared radiation. Ice is transparent to infrared rays. Therefore, the infrared radiation generated by the emitter freely passes through the ice layer to the boundary surface of the coating, which, being opaque, absorbs the rays and heats up. The heat from the surface of the coating, in turn, is transferred to the boundary layer of ice, which leads to the melting of the latter and to the complete weakening of the forces that bind the ice to the coating. The gas-air jet, due to the aerodynamic pressure, breaks the melted ice and carries it out of the cover. The performance of thermal machines is calculated similarly to the performance of snowplows.

Anti-icing machines. Designed to maintain the adhesion properties of the coating in winter at a level that guarantees safe traffic. The most widespread method of dealing with ice is the distribution of sand, granite chips, crystalline and liquid chlorides and various combinations of these substances over the icy coating. Sand and granite chips increase the grip of wheels with an icy surface, but in heavy traffic they are quickly carried to the side of the road. Chlorides initiate the melting of ice and snow run (the freezing point of salt water is well below 0°C), but with a sharp drop in temperature can lead to even more icing. In addition, the presence of excess water on the surface of the coating during high speeds transport is fraught with the danger of aquaplaning.

Machines for the distribution of bulk anti-icing materials, as a rule, are universal and in the warm season they are converted into watering machines. They are mounted on the chassis of serial trucks (Fig. 13), or on specialized pneumatic wheeled chassis.

Sand, granite chips or a mixture of sand and salt are poured into a hopper in the form of a trapezoidal prism, with the smaller base facing down. The open top of the bunker is covered with a gable grate, which plays the role of a sieve. A chain scraper conveyor (feeder) is laid along the bottom of the bunker, carrying the contents to the rear end of the bunker, where a distributing device is installed. A horizontal disk with radial vertical blades on the lower plane, covered by a casing, rotates and scatters the anti-icing material through the slots in the casing over the surrounding surface in a relatively uniform layer. Material flow rate can be controlled by feeder speed, disc rotation speed, size and orientation of shroud feed slots.

The universal spreader KO-104A (Fig. 13) is designed to distribute sand-salt mixture or other chemical reagents used for winter maintenance of streets, squares and roads over the surface of the road surface. In the summer, the spreader is re-equipped and can be used as a dump truck for transporting bulk cargo.

The special equipment of the machine is mounted on the chassis of the GAZ-53A car and consists of a body, a scraper conveyor, a spreading disc and a conveyor hydraulic drive. When re-equipping the spreader into a dump truck, the following are additionally installed: a hydraulic lift bracket, a hydraulic lift, a side closing mechanism, a control crane.

Technological material intended for distribution on the surface of the street or road is fed by a scraper conveyor from the body through the hopper to the spreading disc, which, rotating, evenly spreads it over the road surface. The sprinkling density is regulated in three ways: by changing the speed of the conveyor, by limiting the amount of technological material for sprinkling coming from the conveyor, by changing the speed of the spreading disc.

Figure 13 - Universal spreader KO-104A

1 - conveyor drive gearbox 2 - bunker; 3 - gate lever, 4 - scraper conveyor, 5 - body. 6 - grate, 7 - conveyor tensioning mechanism, 8 - control panel, 9 - spare wheel bracket, 10 - pump; 11 - overframe, 12 - hydraulic system; 13 - spreading disc

The body is an all-metal welded structure with inclined side walls, mounted on a subframe mounted on the chassis side members. A grill of metal rods is installed on the top of the body to prevent large stones, clay or frozen sand from getting into it. A board is hung on the back of the body, to which the bunker is attached. The rear and front sides of the body have openings for the passage of the upper branch of the conveyor. In front, on the side beams of the body, a mechanism for tensioning the conveyor branches is installed. The spreader conveyor (scraper type) is mounted on the sprockets of the drive and driven shafts located in the hopper on the front body brackets. The upper part of the conveyor passes inside the body (scrapers move along its bottom), the lower part - under the bottom of the body (along the guides). Inside the bunker there is a conveyor drive shaft and a gate valve that allows you to adjust the height of the layer of spread materials. Raise and lower the shutter manually with a lever. The spreading disc with a hydraulic motor is installed under the hopper and ensures the distribution of technological materials coming from the hopper.

From the moment when in 2006 in Moscow at the interchanges Yaroslavskoe shosse - MKAD and Altufevskoe shosse - MKAD a domestically developed anti-icing system (FOSS) was installed in Moscow, the number of winter traffic accidents on these sections has decreased several times. This once again confirms that the use of FOSS is today the most effective method in the fight against ice on highways and road junctions.

In foreign countries with a climate similar to Russia, well-known manufacturers have long been supplying road builders with equipment kits that allow treating the roadway on difficult sections of highways and artificial engineering structures with liquid anti-icing reagents using data from automatic measurements of weather parameters or commands from the control room. And six years ago, in 2002, the Moscow government made a decision to develop a domestic system for providing anti-icing conditions. Its implementation was entrusted to Moscow Roads OJSC.

What are anti-icing systems created by domestic specialists?

The first to notify the system about the state of the road and the environment are automatic road weather stations (ADMS) and road sensors - a kind of sentinel that constantly monitors a number of weather parameters - air and roadway temperature, wind strength and direction, snow cover thickness and much more.

The measurement data are sent to the control system of the central pumping station (CNS) - the main element of the FOSS, where the calculation is made and a forecast is made of the possibility of ice formation one or two hours in advance. If the probability of ice formation is high, then the CNS hydraulic system is turned on and the roadway is processed through the spray heads. In this case, the density of applying the reagent depends on how strong the formation of ice is predicted.

The equipment of one or another road section may consist of one or even several (at complex road junctions) central pumping stations. They are equipped with containers for storing liquid de-icing agents, an internal hydraulic system with a pump and a number of electronically controlled valves and gate valves that ensure stable operation of the system with stable pressure. In addition, the central nervous system hosts control, communication and power supply systems.

All this is housed in a convenient and compact transportable module, which is assembled and tested at the factory. It arrives at the place of installation almost ready for operation. From the pumping station, an inexpensive plastic pipeline is laid along the road - a hydraulic line, as well as four electrical wires: two for power and two for control. Every 10-15 meters, blocks are placed that contain a control modem, an electromagnetic valve and a spray head.

Alexander NEFEDOV, General Director of Moscow Roads OJSC, Doctor of Technical Sciences, says:

Our system allows you to really control the situation, understand where and what is happening on the roads, and therefore tells you where to send road cleaning equipment - after all, only the most critical sections of highways, mainly traffic interchanges, are equipped with automatic anti-icing systems, in other areas a mobile technique.

At the same time, our control and measuring equipment allows you to check whether snow was cleared on the highway and, if so, when exactly, since it is equipped with an ultrasonic sensor that determines the thickness of the snow cover with an accuracy of several millimeters. In addition, there are sensors installed directly in the roadway. They measure the temperature on the road surface, at depths of 5 cm and 30 cm in the road surface itself. This is necessary for an accurate forecast of ice formation on the road.

Another important part of the FOSS is the central control center (CDP), where information about the technical condition of the equipment installed on the road sections, meteorological data from the entire region where automatic road weather stations are located is collected. Here they are processed and archived.

In addition, the CDP operator can control the operation of the system, which is necessary when conducting technological works or in the event of an emergency. Specialized software and mathematical software and the hardware complex of the CDP make it possible to manage FOSS through various communication channels and regardless of their location. For example, from Moscow technical center it is possible to control and manage FOSS located in other cities. From the control room, you can also control the work and control the mobile equipment that performs the application of anti-icing reagents.

The main task that we set ourselves is to create a system capable of collecting, processing, filtering data and issuing it to consumers from a single center. A system that combines everything into a single complex, as it allows, on the one hand, to cover the most difficult sections of roads with FOSS anti-icing installations, and, on the other hand, by receiving information from different parts of the region, to more accurately control mobile equipment.

In order to further reduce the cost of equipment and create prerequisites for simplifying and reducing the cost of the operation process, we proposed to transfer all the most complex tasks of forecasting and managing FOSS to a single engineering control center, while maintaining equipment on the road sections with minimal control and monitoring functions. The creation of a single center makes it possible to regionally organize the management of the work of mobile harvesting equipment, based on objective weather data.

This proposal has been submitted for consideration to the complex of urban economy of Moscow. As a pilot project, it is proposed to create a single complex on the third transport ring and in Zelenograd with the subsequent inclusion of other districts of Moscow and already operating SOPOs into it.

The task is not easy, but the specialists of JSC "Moscow Roads" systematically solve it. And today we can already talk about the creation of a domestic anti-icing system that surpasses foreign models in terms of characteristics and has a significantly lower cost.

A number of technical solutions used in the creation of FOSS are protected by patents. All equipment is certified, the automatic road weather station, which is part of the SOPO, is included in the unified State register of measuring instruments. And one of the leading design organizations - State Unitary Enterprise "Mosinzhproekt" - organized the development of methodological recommendations for the design of facilities, taking into account FOSS, with the prospect of creating an enterprise standard and an industry standard based on this document.

It is important to note that FOSS, due to the developed communication structure and the availability of appropriate software, make it easy to equip the system with new control functions - for example, video cameras, additional traffic control sensors, etc.

Alexander NEFEDOV says:

In a number of parameters and technical solutions, our system surpasses foreign analogues. For example, a spray head, developed by us in collaboration with specialists from Moscow State Technical University. Bauman, provides a reagent jet departure distance of about 40% further than foreign analogues. This gives us the opportunity to ensure guaranteed overlap of two, and in some cases even three lanes of the road and not put spray lines and heads in the roadbed.

To stabilize the pressure in the hydraulic system of foreign analogues, receivers are installed along the roadway (one for every 4-8 heads). We solved this problem by adjusting the pump performance during the roadway treatment. This greatly simplifies installation and subsequent maintenance.

All of the above allows us to count on the fact that over time we will enter the foreign market, because in European countries such systems as ours are in great demand. However, domestic consumers will first of all feel the benefit of solving this problem - after all, we offer our products primarily to Russians ...

In the meantime, the specialists of JSC "Moscow Roads" are successfully mastering the Russian expanses. Quite recently, the company won several tenders for the development of a project for the use of its systems on difficult sections of the Moscow Ring Road and interchanges, and two tenders for the supply of equipment for previously completed projects.

Regions also show interest in domestically developed FOSS. So, at the initiative of the Perm Road Committee, the new Krasavinsky Bridge across the river is equipped with such a system. Kamu. And this, together with the access sections, is about 2 km long - three lanes in each direction.

The Ministry of Transport of the Republic of Tatarstan also found financial resources to equip two interchanges on the Kazan-Orenburg highway with an anti-icing system.

Taking into account the advantages and not least the cost of domestic development, as well as the availability of specialists capable of solving complex problems at all stages of creating a system, design organizations GUP "Mosinzhproekt", "Promos" (Moscow), "Transproekt" (Kazan) and a number of others include FOSS in the projects they develop. Specialists of OJSC "Moscow Roads" have completed or participated in the implementation of more than 20 projects for equipping bridges and interchanges, both existing and newly designed ones.

By the way, these developments of the Moscow Roads company could find a very effective application in the construction of roads in the Olympic Sochi. There will be a number of difficult mountainous sections on the Olympic highways, on which, according to meteorologists, ice formation is possible up to 80 times a season - that is, in fact, every two to three days. Therefore, there is a particularly acute issue of accurate meteorological support for road services, as well as equipping particularly difficult sections with stationary anti-icing systems.

And it is better to give preference to domestic developments, bearing in mind not only their more competitive price compared to foreign ones, but also lower operating costs, because FOSS will be used not only during the days of the Winter Olympics, but for many years and even decades after her.

Guidelines for the use of environmentally friendly anti-icing materials and technologies in the maintenance of bridge structures

ODM 218.5.006-2008

Approved
by order of Rosavtodor
dated September 10, 2008 No. 383-r

Moscow 2009

In order to implement in the road sector the main provisions of the Federal Law of December 27, 2002 No.184-FZ"On technical regulation" and providing road organizations with methodological recommendations on the possibility of using new environmentally friendly anti-icing materials and technologies to combat winter slipperiness on bridge structures:

1. Structural subdivisions of the central office of Rosavtodor, federal departments of highways, departments of highways and interregional directorates for road construction of highways of federal significance to recommend for use from September 1, 2008 the attached ODM 218.5.006-2008 " Guidelines on the use of environmentally friendly anti-icing materials and technologies in the maintenance of bridge structures" (hereinafter - ODM 218.5.006-2008).

2. Recommend ODM 218.5.006-2008 to the territorial authorities of the road facilities of the constituent entities of the Russian Federation for use from September 1, 2008.

3. The Department of Affairs (Blinova S.M.) in the prescribed manner ensure the publication of ODM 218.5.006-2008 and send it to the units and organizations mentioned in paragraph 1 of this order.

4. To impose control over the execution of this order on the deputy head S.E. Poleshchuk.

Head O.V. Belozerov

Foreword

1. DEVELOPED: Federal state unitary enterprise "ROSDORNII". The methodological document was developed in accordance with paragraph 3 of Article 4 of the Federal Law of December 27, 2002 No. 184-FZ "On Technical Regulation" - and is an act of a recommendatory nature in the road sector.

2. INTRODUCED: by the Administration for the Operation and Preservation of Highways of the Federal Highway Agency.

3. PUBLISHED: On the basis of the order of the Federal Road Agency of September 10, 2008 No. 383-r.

Section 1. Scope

The sectoral road methodological document "Methodological recommendations for the use of environmentally friendly anti-icing materials and technologies in the maintenance of bridge structures" is an act of a recommendatory nature and was developed as an addition to the "Guidelines for combating winter slipperiness on roads" (ODM 218.3.023-2003).

The Guidelines contain a list of anti-icing materials that can be used to combat winter slipperiness on road bridges and other artificial structures, reveal the features of the operation of road bridges in winter conditions, the requirements for PGM and their distribution norms, as well as the necessary measures for corrosion protection of structural elements of bridges and ensuring the anti-icing condition of road surfaces on artificial structures.

The provisions set forth in the document are recommended for winter maintenance and repair of road bridges.

Section 2. Normative references

This guidance document uses references to the following documents:

At intensity >3000 vehicles/day - 4 hours,

With an intensity of 1000-3000 vehicles / day - 5 hours,

At intensity<1000 авт./сутки - 6 часов,

f) Loose (compacted) snow on sidewalks in populated areas after snow removal should not exceed 5 (3 cm). The term for cleaning sidewalks in settlements is no more than 1 day.

g) Sidewalks not strewn with friction material are not allowed in populated areas. Normative sprinkling time after the end of the snowfall in places with intensive pedestrian traffic:

St. 250 people / hour no more than 1 hour

100-250 people/hour no more than 2 hours

Up to 100 people/hour no more than 3 hours

h) The presence of anti-icing materials on fences and railings is not allowed.

i) It is not allowed to clog the trays of drainage pipes and windows in paving blocks.

j) Loose (melted) snow on the roadway is allowed with a thickness of not more than 1 (2) cm for A1, A2, A3, B; 2 (4) cm for roads B2.

The standard cleaning width is 100%.

k) The term for the elimination of winter slipperiness from the moment of formation (and snow removal from the moment the snowfall ends) to complete elimination, no more than 3 (4) hours for A1, A2, A3; 4 (5) hours for B; 8-12 hours for G1; 10 (16) hours for G2.

l) Snow rolling is not allowed on A1, A2, A3, B; and allowed up to 4 cm for V, G1; up to 6 cm for G2 with heavy traffic no more than 1500 cars / day.

m) The main requirements for the condition of the road surface on artificial structures in winter conditions are given in the Guidelines for assessing the level of road maintenance. M. 2003.

Section 7. Fight against winter slipperiness on bridge structures

a) Measures to prevent and eliminate winter slipperiness on bridge structures include:

Preventive treatment of coatings with chemical anti-icing materials;

Elimination of the formed ice or snow-ice layer with chemical anti-icing materials and / or special road equipment;

Increasing the roughness of the roadway by distributing friction materials (sand, screenings, crushed stone, slag);

The device of special coatings with anti-icing properties.

b) To improve the effectiveness of the fight against winter slipperiness, measures are taken to:

The device of automatic systems for the distribution of liquid PGM and anti-icing coatings on especially critical artificial structures.

Daily provision of meteorological data for the timely organization of the fight against winter slipperiness, especially during preventive treatment of coatings, on artificial structures by creating a system of road meteorological stations (posts).

c) In order to prevent the formation of snow and ice deposits, the distribution of PGM is carried out either preventively (based on weather forecasts) or immediately from the moment the snowfall begins (to prevent snow run-up).

d) The distribution of PGM during snowfalls allows you to keep the falling snow in a loose state.

After the snowfall stops, the snow mass formed on the road is removed from the carriageway by successive passes of plow-brush snowplows.

e) Chemical reagents, to combat winter slipperiness on bridge structures, use only environmentally friendly ones. PGMs produced on the basis of acetates, formates, carbamides and other chlorine-free reagents are environmentally safe.

f) After loosening the rolling (due to partial melting and the impact of the wheels of vehicles), usually within 2-3 hours, loose water-snow mass (sludge) is removed by successive passes of plow-brush snowplows.

g) If vitreous ice forms on the surface (the most dangerous type of winter slipperiness), work to eliminate it consists in the distribution of chemical PGM, the interval (hold) until the ice completely melts, cleaning and cleaning the roadway from the formed solution or sludge (if necessary).

h) In the frictional method of combating winter slipperiness on bridges, sand, stone screenings, crushed stone and slag are used in accordance with the requirements of ODN 218.2.028-2003.

i) Anti-icing materials are distributed evenly over the surface of the coatings in accordance with the necessary distribution norms indicated in Table 1.

Table 1. Approximate norms of chemical anti-icing materials on the carriageway of bridge structures (g / m 2).

PGM Group	Loose snow or rolling at, t °C						vitreous ice, t °С
Liquid, g/m 2
Acetate
Formate
Nitrate
Integrated

Currently, the domestic industry produces anti-icing materials in liquid form on an acetate basis of the "Nordway" type (TU 2149-005-59586231-2006), on a formate basis - of the "FK" type (TU 2149-064-58856807-05); in solid form on nitrate-urea raw materials of the "NKMM" type (TU 2149-051-761643-98) and "ANS" (TU U-6-13441912.001-97). The complex group includes multicomponent PGMs consisting of several salts, the main representative of which is "Biodor" of the "Mosty" brand, manufactured according to TU 2149-001-93988694-06.

j) Friction materials distribution rates are assigned depending on traffic intensity:

- <100 авт./сут-100 г/м 2

500 cars/day-150 g/m2

750 cars/day-200 g/m 2

1000 cars/day-250 g/m 2

1500 cars/day-300 g/m 2

- >2000 avt./day-400 g/m 2

k) The distribution of liquid and solid PGM is carried out by road machines equipped with automatic special distributors and on-board computers, the characteristics of which are given in.

l) In order to increase the efficiency of the use of liquid anti-icing materials, stationary automatic distribution systems equipped with a weather station and a road sensor (SOPO type) are increasingly being used.

Automatic systems have undeniable technical advantages over traditional distributors in terms of the following characteristics:

Improving road safety in winter due to a sharp reduction in the time interval (from the moment of notification to the moment of distribution) for processing the PGM coating;

Automatic control over the condition of the road surface and the amount of PGM on the surface of the carriageway;

The absence of distribution and snow removal facilities on the roadway, which reduce the throughput and, as a result, reduce the amount of harmful emissions into the environment;

Reducing the amount of reagent used due to the use of preventive treatment of the coating, which prevents the formation of snow or ice;

Reducing the release of the reagent to the adjacent territories due to the optimal dosed distribution rate in automatic mode.

Section 8. Requirements for anti-icing materials used on bridge structures

a) Anti-icing materials designed to combat winter slipperiness must meet these requirements and correspond to the conditions of their use (air temperature, precipitation, pavement condition, etc.).

b) On bridge structures, preference is given to PGMs based on acetates (acetic acid salts), formates (formic acid salts) and nitrates (nitric acid salts). At present, the domestic chemical industry has begun the production of complex PGMs for bridge structures. When using other PGMs, structural elements of bridges must be protected with anti-corrosion coatings. The classification of PGMs used to combat winter slipperiness on bridge structures is shown in Figure 1.

Rice. 1 Classification of anti-icing materials for combating winter slipperiness on artificial structures

c) Chemical PGMs used to combat winter slipperiness must perform the following functions:

Lower the freezing point of water;

Accelerate the melting of snow and ice deposits on road surfaces;

Penetrate through layers of snow and ice, destroying intercrystalline bonds, and reduce the forces of freezing with the road surface;

Do not increase the slipperiness of the road surface, especially when using PGM in the form of solutions;

Be technologically advanced during storage, transportation and use;

Do not increase the environmental load on the environment and do not have a toxic effect on humans and animals;

Do not cause an increase in the aggressive effect on metal, concrete, leather and rubber;

d) The properties of chemical PGMs are evaluated according to a number of indicators combined into four groups: organoleptic, physico-chemical, technological and environmental, the main requirements of which are given in table 2.

Table 2. Requirements for chemical anti-icing materials used to combat winter slipperiness on bridge structures.

The name of indicators	Norm
	Solid	Liquid
Organoleptic :
1. Condition	Granules, crystals, flakes	Aqueous solution without mechanical inclusions, sediment and suspension
2. Color	White to light gray (light brown, light pink allowed)	Light, transparent (allowed with a slight yellow or blue color)
3. Smell		None (for settlements)
Physico-chemical :
4. Grain composition, %
Mass fraction of particle size:
St. 10 mm	Not allowed
St. 5 mm up to 10 mm incl., no more
St. 1 mm to 5 mm incl., not less than
1 mm or less, no more
5. Mass fraction of soluble salts (concentration), %, not less than
6. Crystallization start temperature, °С, not higher
7. Humidity %, no more
8. Mass fraction of substances insoluble in water,%, no more
9. Hydrogen index, units pH
10. Density, g / cm 2	0,8-1,15	1,1-1,3
Technological:
11. Melting capacity, g/g, not less than
12. Hygroscopicity, %/day	10-50
13. Slipperiness index, no more
Environmental:
14. Specific effective activity of natural radionuclides for road bridges, Bq/kg, not more than
In settlements
For out-of-town conditions	1500	1500
15. Corrosivity to metal (St. 3) mg/cm 2 day, no more
16. Index of aggressiveness on cement concrete, g/cm 3 , no more	0,07	0,07

e) Frictional PGMs must:

To increase the roughness of snow and ice deposits on pavements to ensure traffic safety;

Have high physical and mechanical properties that prevent destruction, wear, crushing and grinding of PGM;

Possess properties that prevent an increase in air dustiness and pollution.

f) The properties of frictional PGMs are evaluated according to the following indicators: type, appearance, color, grain composition, amount of silt and clay particles, density. Requirements for friction materials are given in Table 3.

Table 3. Requirements for friction anti-icing materials used to combat winter slipperiness on bridge structures.

The name of indicators	Norm
	Sand	screening
1. Grain composition, %
Mass fraction of screening particles with the size:
St. 10 mm		Not allowed
St. 5 mm to 10 mm no more
St. 1 mm to 5 mm, not less
1 mm or less, no more
2. Size modulus	2,0-3,5
3. Mass fraction of dust and clay particles, %, no more
4. Mass fraction of clay in lumps %, no more	0,35	Not allowed
5. Strength grade, not less
6. Humidity, %, no more
7. Specific effective activity of natural radionuclides for road bridges, Bq/kg, not more than
In settlements
For out-of-town conditions	1500	1500

g) The main difference between chemical anti-icing materials used on artificial structures is the absence of their aggressive effect on metal and concrete structural elements. In this regard, during incoming inspection and certification tests, as well as at the request of the customer, the supplied PGMs are evaluated, including corrosion activity on metal and concrete according to the methods given in.

Section 9. Special coatings with anti-icing properties

On special coatings with anti-icing properties, the adhesion of snow and ice deposits to coatings is reduced, thin layers of ice are melted, the amount of PGM is reduced, the time of ice hazard in the transitional autumn-winter period is reduced, and the corrosive effect on vehicles and negative environmental impact are reduced.

a) Special coatings with anti-icing properties are arranged by introducing anti-icing additives in an amount of 0.5-2% in two ways:

Introduction to the mixture with mixing at asphalt plants;

The introduction of additives in the process of laying asphalt concrete under the paver during mixing with an auger.

b) A coating with anti-icing properties can be arranged with the addition of crumb rubber with a size of 2-3 mm in an amount of 3-4% of the mineral part of the mixture.

c) On bridges, it is possible to install an asphalt concrete pavement with improved thermal properties due to the use of aggregates with a higher heat capacity (slag, perlite, etc.), which reduce the time of ice hazard, especially during the transition period.

d) Calcium chloride (not more than 0.5%), calcium or magnesium nitrate (up to 2%), calcium, magnesium and potassium acetates can be used as anti-icing additives.

Ammonium and sodium fluorides are recommended as anti-deformation additives. The best is a two-component composition: reagents + fluoride in a ratio of 4:1. The components are introduced into the mixer before the introduction of bitumen, i. when mixing mineral materials.

e) Additives can be introduced in pure form, as an additive to mineral powder or by impregnation of asphalt concrete aggregates with anti-icing agents.

f) The presence of PGM in asphalt concrete contributes to the appearance of an anti-icing non-freezing solution on the pavement, which reduces the adhesion of snow and ice formations to the pavement and prevents icing of the pavement. The solution film is formed due to the release of PGM from asphalt concrete, due to its capillary-porous structure (air gap).

The action of this method is effective from 0°С to minus 5°С.

Section 10. Protection of the natural environment

a) The main task of environmental protection during the winter maintenance of bridge structures is the maximum possible reduction of damage to the natural environment through the use of environmentally friendly materials and technologies, as well as the implementation of a system of environmental protection measures.

b) During the winter maintenance of bridge structures, it is necessary:

Ensure the conservation of flora and fauna;

To carry out protection of surface waters from pollution by harmful PGMs.

c) All activities related to water resources (rivers, lakes, etc.) are carried out in compliance with the "Water Code of the Russian Federation", "Regulations on the Protection of Fish Stocks and Regulation of Fishing in the Reservoirs of the Russian Federation", "Rules for the Protection of Surface Waters from Pollution".

d) In the fight against winter slipperiness on bridges, preference should be given to the preventive method.

e) Environmental safety is achieved through the correct choice of certified PGMs, the implementation of technological regulations, compliance with production discipline, organizational measures and technical solutions.

Section 11. Protection of road bridges

On road bridges, the elements that are in close proximity to the surface of the carriageway, which are exposed to chemical anti-icing materials in winter (expansion joints, sidewalk blocks, drainage devices, railings, fences, etc.) are most susceptible to corrosion.

a) Sources of corrosion during the operation of bridges in winter are:

Periodic moistening of all metal structures with atmospheric precipitation - rain, snow, fog, dew;

Application of anti-icing materials containing aggressive compounds;

The use of sand and other friction materials that cause an abrasive effect on the structural elements of bridge structures.

b) Protection of metal structures of bridges should be carried out:

Lacquer coatings;

Combined metallization and paint coatings.

c) Anti-corrosion protective coatings must meet the following basic requirements:

Reliably protect surfaces from corrosion in the operating temperature range from +70°С to minus 60°С under the influence of atmospheric and climatic factors and environmental aggressiveness;

Possess high physical and mechanical properties: adhesion, hardness, film impact strength and bending elasticity, abrasion resistance, especially at low temperatures. Coatings should not crack or flake off;

Differ in chemical resistance to aggressive environments, the action of chlorides, acids, sulfurous gases, etc.;

Coatings must have high moisture resistance.

d) To improve the durability of anti-corrosion coatings, the following measures are necessary:

Timely partial repair painting of surfaces in areas with damaged coating;

Replacing the paintwork.

e) The technological process of painting includes:

surface preparation;

Sealing cracks and sealing leaks (if necessary);

Priming of the metal surface;

Painting with coating materials in accordance with accepted coating systems;

Drying of each coating layer;

Quality control at each stage of the production of works, as well as the entire coating as a whole.

f) The preparation of working compositions of paints and varnishes consists in performing the following operations:

Mixing of paints and varnishes to a homogeneous consistency;

Adding a hardener (for two-component materials);

The introduction of a solvent (diluent), taking into account the chosen method of application;

Filtration of paints and varnishes (if necessary).

g) All operations for the implementation of technological painting should be carried out at an air temperature of 5 to 30 ° C, relative humidity of air not more than 80%, in the absence of precipitation, fog, dew and exposure to aggressive agents.

h) The application of paints and varnishes, as a rule, must be done by spraying.

i) When protecting metal structures using metallization, the coating is applied immediately after surface preparation at an air humidity of not more than 85%.

j) For coating, gas-flame and electric arc installations, as well as electric metallizers, can be used.

k) Painting of the metallization layer with paintwork material is carried out immediately after metallization directly over the metallization layer without any surface preparation.

l) Control over the quality of work on corrosion protection of metal structures of the bridge is carried out at all stages of the technological process.

m) Detailed technologies and characteristics of paint and varnish materials are given in the Guidelines for the protection of metal structures from corrosion and the repair of paint and varnish coatings of metal superstructures of operated road bridges. M. 2003.

o) Reinforced concrete road bridges are protected in two ways:

Hydrophobization of the concrete surface;

Applying paintwork.

n) Hydrophobization is carried out with organosilicon liquids.

p) Acrylic and perchlorovinyl paints and enamels are used for coatings.

Annex A
Technical characteristics of anti-icing materials distributors

No. p. p.	Name and location of the manufacturer	Machine brand	Base Chassis	Installation of equipment dovaniya	Body capacity, m 3	Distribution width divisions, m	Raft- distribution divisions, g / m 2	Speed ​​up to km/h		Add- lnoe equipment for winter maintenance
								Trance- tailor	working
	OJSC "Amurdormash" Amur Region, settlement ?	ED-403D-01	ZIL-431412	Stationary sledge-removable	3,25	4,0-10,6	25-940			Front blade, middle brush
		ED-242	KAMA 3-55111, 65111	Hinged to the dump truck body (0.7 m 3)	6,6; 8,2	4,0-6,0	100-400			Front speed dozer
	Saratov plant road-?	4906	ZIL-4331	Stationary sledge-removable	3,25	up to 8.5	50-1000			front blade
		DM-32, DM-32M	ZIL-431410
		DM-1, DM-28-10, DM-6m-30	KAMA3-55111, MAZ-5551, 3IL-4520	Fast- removable in the body of a / m			25-500			Front speed dozer
		DM-34, DM-39	MAZ-5334, KAMAZ-5320	Stationary sledge-removable			50-1000			Front, middle and side high-speed blades (for KAMAZ)
		DM-6m, DM-38, DM-41	KAMAZ-5320, ZIL-133 TYA, T40, KAMAZ-55111	Fast- removable in the body of a / m			25-500			Front speed dozer
	CJSC "Smolensk auto-aggregate plant"	MDK-433362-00, 01, 05, 06	ZIL-433362	Stationary sledge-removable		3,0-9,0	10-400			Front blade, brush
		MDK-133 G4-81	ZIL-133 G4			4,0-9,0	25-400			Front Blade, Speed ​​Blade, Side Blade, Brush
		MDK-5337 -00, 01, 05, 06	MAZ-533700			3,0-9,0	10-400			Front blade, brush
	JSC "Complex road machines"	KDM-130V, ED-226	ZIL-433362, ZIL-433102	Stationary sledge-removable	3,25	4,0-10,0	25-500			Front blade, brush
		ED-224	MAZ-5337			4,0-12,0	10-500
		EL-403, ED-410	ZIL-133 G4, D4				25-500
		ED-405, ED-405A	KAMAZ-53213, KAMAZ-55111				10-500
		ED-243 (equipment of Schmidt, Germany)	MAZ-63039			2,0-12,0	5-500			Front, side plow, brush
	JSC "Novosibirsk Plant of Road Machines"	ED-242	Dump trucks of the ZIL, KAMAZ, URAL families	mounted to the dump truck body (0.7 m 3)	3,25; 5,6; 6,2	4,0-6,0	100-400			Front Blade, Speed ​​Blade
		ED-240	ZIL-433362, ZIL-133 G4, KAMAZ-55111	Stationary sledge-removable		4,0-10,6	25-500			front blade, speed blade, brush
	JSC NPO "Rosdormash" Moscow region, Mamontovka	KO-713M, KO-713-02M	ZIL-433362, ZIL-433360	Stationary sledge-removable	3,25	4,0-10,0	25-500			Front blade, brush
	JSC "Sevdormash" Arkhangelsk region, Severodvinsk	KO-713M	ZIL-433362	Stationary sledge-removable		4,0-9,0	50-300			Front blade, brush
	OJSC "Mtsensk Plant"	KO-713-02, KO-713-03	ZIL-433362	Stationary sledge-removable		4,0-9,0	50-300			Front blade, brush
		KO-806	KAMAZ-4925
		KO-823	KAMAZ-53229
	"Tosnensky Mechanical Plant" (ToMeZ) Leningrad Region Tosno	KDM-69283 ("Falcon")	KAMAZ-53229	Stationary sledge-removable		4,0-9,0	25-500			Front conventional, speed blade, side blade, front brush, medium
	OJSC "Kemerovo Experimental Mechanical Repair Plant", Kemerovo	DMK-10	KRAZ-6510	Hinged to the dump truck body		4,0-6,0	125-400
	JSC "Motovilikhinskiye Zavody", Perm	KM-500	KAMAZ-53213	Stationary sledge-removable		4,0-10,0	25-500			Front blade, speed blade and medium blade
		MKDS-2004	ZIL-133 D4			4,0-10,0	10-300			Front Blade, Speed ​​Blade, Brush
	Concern "Amkodor" Republic of Belarus, Minsk	NO-075	MAZ-5551	Fast- removable in the body of a / m		2,0-8,0	5-40			front blade
	LLC "Eurasia", Chelyabinsk	Troika-2000	Ural-55571-30, Ural-Iveco	Fast- removable in the body of a / m		6,0-14,0	20-400			Front blade, speed, medium, side, brush
	JSC "Arzamas plant of municipal engineering Nizhny Novgorod region. Arzamas	KO-829	ZIL-433362	Stationary sledge-removable	-«-	4,0-9,0	25-500			Front blade, brush
	JSC "Kurgandormash" Kurgan	MD-433	ZIL-433362	-«-		4,0-9,0	100-400	60	30	Front blade, brush
		KUM-99	ZIL-452632	-«-	4,0	3,0-9,0	10-300	60	30	-«-
17.	JSC "Mosdormash", Moscow	KUM-99	ZIL-452632	-«-	4,0	4,0-9,0	10-300	60	40	-«-
		KUM-104	MAZ-533702	-«-	8,0	1,75-7,0	20-200	60	50	-«-
		KUM-105	KAMAZ 43253	-«-	9,0	1,75-7,0	20-200	60	50	-«-

Annex B
Test methods for anti-icing
materials FOR CEMENT CONCRETE AND METAL

B.1. Method for determining the aggressive effect of anti-icing materials on cement concrete

Method Essence

The method involves testing concrete for corrosion resistance against the combined action of anti-icing materials and frost at low air temperatures. The acceleration of the process is achieved by lowering the freezing temperature to minus 50 ± 5 ° C in accordance with GOST 10060.2-95.

As a measure of the aggressive effect of PGM on cement concrete, the ability of the samples to maintain the state (no cracks, chips, surface peeling, etc.) and mass during repeated variable freezing-thawing in the PGM solution was taken. For the criterion of corrosion resistance take the value of the allowable weight loss of the tested samples, reduced to its volume, in the amount of 0.07 g/cm 3 (Δm d oud ).

Equipment

- Laboratory scales for hydrostatic weighing with an accuracy of 0.02 g;

- Equipment for the manufacture and storage of concrete samples must comply with the requirements of GOST 22685 and GOST 10180;

- Freezer, providing achievement and maintenance of temperature up to minus 50±5 °С;

- Vessels for saturation and testing of samples in PGM solution made of corrosion-resistant materials;

- Bath for thawing samples, equipped with a device for maintaining the temperature of the PGM solution within 20 ± 2°C.

- Vacuum cabinet.

Preparing for the test

Concrete samples (made of concrete B30 (M400) or taken in the form of samples (cores) from bridge structures) should not have external defects. The number of samples for one test series must be at least 6 pcs. Before testing, the samples are dried to constant weight in an oven at a temperature of 100 ± 5°C. Samples are marked, geometric dimensions are measured, external condition is assessed and weighed.

PGM solutions of 10% concentration are prepared for testing.

The samples are saturated in the PGM solution in a vacuum cabinet for 1 hour, kept at room temperature for 1 hour and weighed in air and in water. The volume of concrete samples after water saturation is determined by hydrostatic weighing according to GOST 12730.1. Weighing accuracy up to 0.02 g.

Conducting a test

Concrete samples after saturation are subjected to freeze-thaw tests.

To do this, saturated samples are placed in a container filled with the same solution on two wooden spacers: in this case, the distance between the samples and the walls of the container should be 10 ± 2 mm, the liquid layer above the surface of the samples should be at least 20 ± 2 mm.

The samples are placed in a freezer at an air temperature not higher than minus 10°C in containers closed at the top so that the distance between the walls of the containers and the chamber is at least 50 mm.

After establishing a temperature of minus 10 ° C in a closed chamber, it is lowered within 1 (± 0.25) hours to minus 50 ± 5 ° C and exposure is made at this temperature for 1 (± 0.25) hours.

Next, the temperature in the chamber is increased for 1 ± 0.5 hours to minus 10°C, and at this temperature, containers with samples are unloaded from it. The samples are thawed for 1 ± 0.25 hours in a bath with a PGM solution at a temperature of 20 ± 2°C. In this case, the containers with samples are immersed in the bath in such a way that each of them is surrounded by a liquid layer of at least 50 mm.

The total number of test cycles depends on the state of the samples and the aggressiveness of the PGM. The number of sample test cycles per day must be at least one. In the event of a forced break in the test, the samples are stored in the PGM solution for no more than five days. If the test is interrupted for more than five days, they are resumed on new series of samples. After every five cycles of testing, the state of the samples (the appearance of cracks, chips, surface peeling) and the mass are monitored by weighing. Before weighing, the samples are washed with clean water, the surface is dried with a damp cloth.

After every five cycles of alternate freezing-thawing, 10% PGM solutions in the containers and the thawing bath should be changed to newly prepared ones.

Results processing

After the test, the state of the samples is visually assessed: the presence of cracks, chips, peeling and other defects. The aggressiveness of PGM in relation to cement concrete is evaluated by reducing the mass of samples reduced to their volume.

The assessment of the degree of aggressiveness of the tested reagent is carried out in the following sequence:

- Determine the volume ( V) samples according to the results of weighing in air and in water (hydrostatic weighing):

where

m 0 is the mass of the sample saturated in a 10% PGM solution in a vacuum cabinet, determined by weighing in air, g;

m in is the mass of the sample saturated in a 10% PGM solution in a vacuum cabinet, determined by weighing in water, g;

ρ in - the density of water, taken equal to 1 g/cm 3 .

- Determine the mass loss of the sample Δm n after 5, 10, 15, 20 accelerated test cycles (according to GOST 10060.0-95 Table 3):

G,

where

m n - mass of the sample, determined by weighing in air, after " n"freeze-thaw cycles;

- Determine the specific change in mass of the sample Δm oud , related to its volume:

.

Build a graph of the dependence of the specific mass change of the sample on the number of test cycles.

The limiting value of the specific mass change of the samples is Δm oud \u003d 0.07 g / cm 3. Concrete samples with values ​​above this indicator are considered to have failed the test.

B.2. Method for determining corrosivity
anti-icing materials for metal

Method Essence

The rate of weight loss per unit area of ​​the sample for a certain period of time GOST 9.905-82 was taken as a measure of the aggressive effect of the anti-icing material on the metal.

Acceleration of the corrosion process is achieved by immersing a metal sample in a solution of an anti-icing material of a certain concentration, followed by drying it in air and in an oven and keeping 100% humidity in a steam-air environment.

Equipment and reagents

- Analytical balance with an error of 0.0002 g according to GOST 24104-88;

- Drying cabinet, TU 16-681.032.84;

- Desiccators according to GOST 25336-82;

- Glass glasses with a volume of 200-500 ml in accordance with GOST 23932-90;

- Flat metal plates of rectangular or square shape made of steel (grade St.-3) with a size of 50 × 50 × 0.5 mm or 100 × 100 × 1.5 mm. Permissible error in the manufacture of plates ± 1 mm for the width and length of the plate and ± 1 mm for the thickness.

- Reagents: etched hydrochloric acid according to GOST 3118-77 with urotropin inhibitor, sodium bicarbonate (soda) according to GOST 2156-76; acetone according to GOST 2768-84.

Preparing for the test

The plates are marked by branding or holes are drilled at the corners of the plates, into which tags are then attached, while the edges of the samples and the edges of the holes should not have a burr. Preparation of samples for testing is carried out in accordance with GOST 9.909-86.

Metal plates are degreased with alcohol or acetone. In this case, it is allowed to use light brushes, brushes, cotton wool, cellulose. After degreasing, the plates are taken only by the ends with hands in cotton gloves or with tweezers. Before testing, the geometric dimensions of the plates are measured, their area is calculated (6 surfaces) and weighed on an analytical balance with an error of 0.0002 g.

Testing of metal plates is carried out in PGM solutions of 5% and 20% concentration. The amount of solution in the test container must be at least 50 cm 3 per 1 cm 2 of the surface of the plate, taking into account their complete immersion in the solution. The distance between the plates and to the walls of the container must be at least 10 mm.

Testing

The metal plates are immersed in a corrosive environment (PGM solution) for 1 hour. The plates are removed from the solution and kept in air for 1 hour. Then they are dried in an oven at a temperature of 60 ± 2°C for 1 hour. = 100%) and kept with the lid closed for 2 days. Upon completion of the tests, the plates are washed with a stream of distilled water (GOST 6709-72). Dry with filter paper and a soft cloth. Solid corrosion products are removed from the surface of the plates by a chemical method, in accordance with GOST 9.907-83. The essence of the chemical method is the dissolution of corrosion products in a solution of a certain composition. The plates are treated with hydrochloric acid with the addition of an urotropine inhibitor or etched with zinc until the corrosion is completely removed. Then washed with running water, neutralized in a solution of bicarbonate soda 5% concentration and degreased with acetone. After processing, the plates are washed with distilled water, dried with filter paper (soft rags) and placed in an oven at a temperature of 60 ° C for 0.5-1 h. Before weighing, the plates are kept in a desiccator with a drying agent (CaCl 2 ) 24 hours. Weighing is carried out on an analytical balance.

Results processing

The rate of mass loss per unit area of ​​the sample is taken as the main quantitative indicator of corrosion.

Corrosion rate ( TO) is calculated by the formula:

mg / cm 2,

where

Δ m - weight loss of the sample, mg;

S - sample surface area, cm 2 ;

t - test duration, 1 day.

Keywords: anti-icing on bridges, winter slipperiness, anti-icing materials, acetates, nitrates, formates.

ODM 218.5.006-2008

INDUSTRY ROAD GUIDELINE

Foreword

1. DEVELOPED: Federal state unitary enterprise "ROSDORNII". The methodological document was developed in accordance with paragraph 3 of Article 4 of the Federal Law of December 27, 2002 N 184-FZ "On Technical Regulation" and is an act of a recommendatory nature in the road sector.

2. INTRODUCED: by the Administration for the Operation and Preservation of Highways of the Federal Highway Agency.

3. PUBLISHED: Based on the order of the Federal Road Agency of September 10, 2008 N 383-r.

Section 1. Scope

Section 1. Scope

The sectoral road methodological document "Methodological recommendations for the use of environmentally friendly anti-icing materials and technologies in the maintenance of bridge structures" is an act of a recommendatory nature and was developed as an addition to the "Guidelines for combating winter slipperiness on roads" (ODM 218.3.023-2003).

The guidelines contain a list of anti-icing materials that can be used to combat winter slipperiness on road bridges and other artificial structures, reveal the features of the operation of road bridges in winter conditions, the requirements for HM and their distribution norms, as well as the necessary measures for corrosion protection of structural elements of bridges and ensuring the anti-icing condition of road surfaces on artificial structures.

The provisions set forth in the document are recommended for winter maintenance and repair of road bridges.

Section 2. Normative references

This guidance document uses references to the following documents:

a) Guidelines for assessing the level of road maintenance. * Temporary. M., 2003.
________________
*Document not cited. For more information, refer to the link , here and further in the text. - Database manufacturer's note.

b) Guidelines for the repair and maintenance of public roads (Draft). M., 2008.

c) Guidelines for assessing the transport and operational condition of bridge structures. ODN 218.0.017-2003. M., 2003.

d) Guidelines for the protection of metal structures from corrosion and the repair of paint and varnish coatings of metal superstructures of operated road bridges *. M., 2003.
________________
* The document is not valid on the territory of the Russian Federation. ODM 218.4.002-2009 is in force, hereinafter in the text. - Database manufacturer's note.

e) Guidelines for the maintenance of bridge structures on highways. Rosavtodor. M., 1999.

f) Guidelines for combating winter slipperiness on roads. ODM 218.3.023-2003. M., 2003.

g) Requirements for anti-icing materials. ODN 218.2.027-2003. M., 2003.

h) Test method for anti-icing materials. ODM 218.2.028-2003. M., 2003.

j) Guidelines for the protection of watercourses from pollution by surface runoff from operated road bridges *. M., 1991.
________________
* The document is the author's development. See the link for more information. - Database manufacturer's note.

l) Guidelines for the use of the "Grikol" filler in the composition of asphalt concrete mixtures for pavement with anti-icing properties. M., 2002.

m) Indicators and norms of environmental safety of the highway. M., 2003.

Section 3. Terms and definitions

In this methodological document, the following terms are used with the corresponding definitions:

Winter content- works and measures to protect roads and artificial structures on them in winter from snow deposits, drifts and avalanches, to clear snow, to prevent the formation and elimination of winter slipperiness and to combat icing.

Winter slipperiness- snow deposits and ice formations on the road surface, leading to a decrease in the coefficient of adhesion of the vehicle wheel to the surface of the road.

loose snow- is formed on the road surface when solid precipitation falls in calm weather and is deposited in the form of a layer even in thickness.

Snow roll- is a layer of snow compacted by the wheels of road transport under certain meteorological conditions.

vitreous ice- appears on the coating in the form of a smooth vitreous film 1-3 mm thick under various weather conditions.

Anti-icing materials (PGM)- solid (loose) or liquid road maintenance materials (friction, chemical) or their mixtures used to combat winter slipperiness on roads.

environmentally friendly- safe anti-icing materials (EKPGM) - solid and liquid PGMs that do not cause harmful effects on the environment (water, soil, plants, etc.) and structural elements of the road (bridges, fences, coatings, etc.) .

Friction PGMs- materials that increase the coefficient of adhesion with snow and ice deposits on the surface to ensure safe driving conditions.

Chemical PGMs- reagents capable of melting snow and ice deposits on road surfaces at negative air temperatures.

Section 4. General Provisions

a) The most important structures on roads are artificial structures and, first of all, road bridges, the main task of which is the uninterrupted and safe passage of vehicles and pedestrians through water obstacles in different seasons of the year. Particularly unfavorable conditions for the movement of cars and pedestrians occur in winter, when snow and ice deposits form on the roadway, contributing to the deterioration of the transport and operational condition and road safety on the bridge structure.

Therefore, one of the main tasks of winter maintenance includes measures to prevent the formation and elimination of snow and ice deposits on the roadbed and sidewalks of bridge structures. The solution to this problem is achieved by carrying out various works to maintain the roadway in a condition that meets the requirements of GOST R 50597-93 "Roads. Requirements for an operational state acceptable under the terms of road safety."

b) Improving the condition of bridge structures in winter conditions is achieved by treating the surface of the coating with chemical or combined anti-icing materials (PGM) with subsequent cleaning of road sludge from the carriageway of road bridges.

As chemical anti-icing materials to combat winter slipperiness on bridge structures, reagents are now increasingly being used that do not have a negative impact not only on the environment, but also on the structural elements of road bridges. Such reagents include de-icing materials produced on acetate (HNSCOO), formate (HCOOH), carbamide (CO (NH)) and other chlorine-free bases, as well as chlorine-containing materials with anti-corrosion and biological additives (environmentally safe de-icing materials - (EC PGM ), dramatically reducing the negative impact on concrete, metal structures of bridges and environmental elements.

The effectiveness of using these materials to combat winter slipperiness on road bridges primarily depends on the ability to take into account constant meteorological data for a particular facility and the use of modern mobile and stationary distribution plants.

c) Guidelines for the use of environmentally friendly anti-icing materials and technologies in the maintenance of bridge structures were developed for the first time on the basis of domestic and foreign experience as an addition to the Guidelines for combating winter slipperiness on roads. ODM 218.3.023-2003.

d) The Recommendations regulate the procedure for carrying out measures to combat winter slipperiness, test methods for HM, as well as work that provides the required operating conditions for bridge structures using various HM and technologies.

Section 5. Features of the operation of bridge structures in winter conditions

a) Bridge structures in operation are constantly exposed to traffic loads and various natural phenomena. Natural phenomena primarily include time-varying temperature and humidity, atmospheric precipitation, and the effects of water.

b) In particularly difficult conditions are artificial structures operated in areas with frequent zero crossings, i.e. from negative to positive temperatures and vice versa.

c) The state of artificial structures on highways is negatively affected by dynamic loads from vehicles, which cause fatigue phenomena in the material of the structure.

d) To a greater extent, external climatic and transport influences are exposed to the bridge deck - the pavement of the carriageway, expansion joints and junctions of the bridge with the embankment, sidewalks, railings and safety fences.

e) On reinforced concrete superstructures, the combination of external influences and loads first causes surface defects on the concrete in the form of its peeling, then the appearance of a chip of weakly adhered concrete particles and the formation of deep gouges, peeling of the protective layer with exposure and corrosion of reinforcing bars.

f) In metal span structures, corrosion of the metal is observed from the influence of the external environment. When the protective coatings are destroyed, a rust coating forms on the metal, which gradually increases in size, reaching a level that reduces the bearing capacity of the main elements of the span structures.

g) On road bridges, which have a lower heat capacity than road pavement on the subgrade and have a lower pavement temperature at night, icing conditions occur more often.

h) The formation of slipperiness on bridges is facilitated by higher relative humidity in the floodplains of rivers and other water bodies, especially during the transitional period before the establishment of ice cover, as well as on artificial structures near large thermal power plants and enterprises. Therefore, the effectiveness of the fight against winter slipperiness at such facilities, especially at out-of-class bridge structures, depends entirely on the timely use of reliable meteorological data that can be obtained from automatic road weather stations installed in the immediate vicinity of the facility.

i) It is prohibited to dump snow and ice from bridge structures.

j) Before the beginning of the winter season, it is necessary to carefully seal (repair) the places of destruction of the coating and all structural elements of the structure, especially with exposed metal reinforcement, broken waterproofing, expansion joints and drainage.

They carry out works on cleaning from rust and dirt and painting metal elements and structures with paints and varnishes.

k) On the structural ledges of bridges, overpasses, overpasses (crossbars, nozzles, sidewalk consoles, etc.), it is necessary to remove snow if its thickness exceeds 10 cm. First of all, the south side of the structure is cleaned.

m) In the spring, after the end of winter work on artificial structures, various elements (sinuses, expansion joints, bearing parts, etc.) are thoroughly washed using special detergents to reduce corrosion, which increases with increasing air temperature.

m) All types of winter slipperiness on bridges and other artificial structures are divided into loose snow, snow run, vitreous ice.

Section 6. Requirements for the condition of the road surface on artificial structures in winter

a) The maintenance of an artificial structure includes cleaning the elements of the bridge deck and load-bearing structures from snow and ice.

b) The roadway and sidewalks are cleared of snow and ice, in case of ice they are sprinkled with sand, fuel slag or crushed stone.

c) After a snowfall and during thaws, melted snow and anti-icing materials are shifted to the fences, followed by their removal from the bridge. Snow removal from shafts is carried out by auger and rotary auger road machines, motor graders, bulldozers and other mechanisms with snow loading into dump trucks and removal outside the structure to snow dumps.

d) Drainage devices, if necessary, are washed with hot water in the spring.

e) The frequency of work on cleaning the roadway is determined by local conditions, but at least once every 10 days, during snowfalls - daily. The directive deadlines for clearing snow and completing the fight against winter slipperiness, including the cleaning of swaths of snow mass shifted from the middle part of the bridge structures, correspond to (GOST 50597-93):

- at intensity >3000 vehicles/day - 4 h,

- at an intensity of 1000-3000 vehicles / day - 5 hours,

- at intensity<1000 авт./сут - 6 ч.

f) Loose (compacted) snow on sidewalks in populated areas after snow removal should not exceed 5 (3) cm. The term for cleaning sidewalks in populated areas is no more than 1 day.

g) Sidewalks not strewn with friction material are not allowed in populated areas. Normative sprinkling time after the end of the snowfall in places with intensive pedestrian traffic:

- over 250 people/hour no more than 1 hour;

- 100-250 people/hour no more than 2 hours;

- up to 100 people/hour no more than 3 hours

h) The presence of anti-icing materials on fences and railings is not allowed.

i) It is not allowed to clog the trays of drainage pipes and windows in paving blocks.

j) Loose (melted) snow on the roadway is allowed with a thickness of not more than 1 (2) cm for A1, A2, A3, B; 2 (4) cm - for B2 roads.

The standard cleaning width is 100%.

k) The term for eliminating winter slipperiness from the moment of formation (and snow removal from the moment the snowfall ends) to complete elimination is no more than 3 (4) hours for A1, A2, A3; 4 (5) hours for B; 8-12 hours for G1; 10 (16) hours for G2.

l) Snow rolling is not allowed on A1, A2, A3, B; and allowed up to 4 cm for V, G1; up to 6 cm for G2 with heavy traffic no more than 1500 cars / day.

m) The main requirements for the condition of the road surface on artificial structures in winter conditions are given in the "Guidelines for assessing the level of maintenance of highways". M., 2003.

Section 7. Fight against winter slipperiness on bridge structures

a) Measures to prevent and eliminate winter slipperiness on bridge structures include:

- preventive treatment of coatings with chemical anti-icing materials;

- elimination of the formed ice or snow-ice layer with chemical anti-icing materials and/or special road equipment;

- increasing the roughness of the roadway by distributing friction materials (sand, screenings, crushed stone, slag);

- installation of special coatings with anti-icing properties.

b) To improve the effectiveness of the fight against winter slipperiness, measures are taken to:

- installation of automatic distribution systems for liquid PGM and anti-icing coatings on especially critical artificial structures;

- daily provision of meteorological data for the timely organization of the fight against winter slipperiness, especially during preventive treatment of coatings, on artificial structures by creating a system of road meteorological stations (posts).

c) In order to prevent the formation of snow-ice deposits on the surface, the distribution of PGM is carried out in advance (based on the weather forecast) or immediately from the moment the snowfall begins (to prevent snow run-up).

d) The distribution of PGM during snowfalls allows you to keep the falling snow in a loose state.

After the snowfall stops, the loose snow mass formed on the road is removed from the carriageway by successive passes of plow-brush snowplows.

e) Chemical reagents to combat winter slipperiness on bridge structures are used only environmentally friendly. PGMs produced on the basis of acetates, formates, carbamides and other similar reagents are environmentally safe.

f) After loosening the rolling (due to partial melting and the impact of the wheels of road transport), usually within 2-3 hours, loose water-snow mass (sludge) is removed by successive passes of plow-brush snowplows.

g) If vitreous ice (the most dangerous type of winter slipperiness) forms on the surface, work to eliminate it consists in distributing chemical PGM in the interval (holding) until the ice completely melts, in cleaning and cleaning the roadway from the resulting solution or sludge.

h) In the frictional method of combating winter slipperiness on bridges, sand, stone screenings, crushed stone and slag are used in accordance with the requirements of ODN.218.2.028-2003.

i) Anti-icing materials are distributed evenly over the surface of the coatings in accordance with the necessary distribution norms indicated in Table 1.

Table 1

Approximate norms of chemical anti-icing materials on the carriageway of bridge structures (g / m)

PGM Group	Loose snow or rolling at, °C						Vitreous ice, °C
Acetate
Formate
Nitrate
Integrated

Currently, the domestic industry produces anti-icing materials in liquid form on an acetate basis of the "Nordway" type (TU 2149-005-59586231-2006*), on a formate basis - of the "FK" type (TU 2149-064-58856807-05*); in solid form on nitrate-carbamide raw materials of the "NKMM" type (TU 2149-051-761643-98*) and "ANS" (TU U-6-13441912.001-97*). The complex group includes multicomponent PGMs consisting of several salts, the main representative of which is "Biodor" brand "Mosti", produced according to TU 2149-001-93988694-06*.
________________
* Specifications mentioned hereinafter are the author's development. See the link for more information. - Database manufacturer's note.

j) Friction materials distribution rates are assigned depending on traffic intensity:

- <100 авт./сут - 100 г/м;

- 500 cars / day - 150 g / m;

- 750 cars / day - 200 g / m;

- 1000 cars / day - 250 g / m;

- 1500 cars / day - 300 g / m;

- >2000 cars/day - 400 g/m.

k) The distribution of liquid and solid PGM is carried out by road machines equipped with automatic special distributors and on-board computers, the characteristics of which are given in Appendix A.

l) In order to increase the efficiency of the use of liquid anti-icing materials, stationary automatic distribution systems (such as SOPO) equipped with a pumping station, a weather station and a road sensor are increasingly being used.

Automatic systems have undeniable technical advantages over traditional distributors in terms of the following characteristics:

- improving road safety in winter due to a sharp reduction in the time interval (from the moment of notification to the moment of distribution) for processing the PGM coating;

- automatic control over the condition of the road surface and the amount of PGM on the surface of the carriageway;

- the absence of distribution and snow removal facilities on the roadway, which reduce the throughput and, as a result, reduce the amount of harmful emissions into the environment;

- reducing the amount of reagent used due to the use of preventive treatment of the coating, which prevents the formation of snow or ice;

- reducing the release of the reagent to the adjacent territories due to the optimal dosed distribution rate in automatic mode.

Section 8. Requirements for anti-icing materials used on bridge structures

a) Anti-icing materials designed to combat winter slipperiness must meet these requirements and correspond to the conditions of their use (air temperature, precipitation, pavement condition, etc.).

b) On bridge structures, preference is given to PGMs based on acetates (salts of acetic acid), formates (salts of formic acid) and nitrates (salts of nitric acid). At present, the domestic chemical industry has begun the production of complex PGMs for bridge structures. When using other PGMs, structural elements of bridges must be protected with anti-corrosion coatings. The classification of PGMs used to combat winter slipperiness on bridge structures is shown in the figure.

Classification of anti-icing materials to combat winter slipperiness on artificial structures

Classification of anti-icing materials to combat winter slipperiness on artificial structures

c) Chemical PGMs used to combat winter slipperiness must perform the following functions:

- lower the freezing point of water;

- accelerate the melting of snow and ice deposits on road surfaces;

- penetrate through layers of snow and ice, destroying intercrystalline bonds, and reduce the freezing forces with the road surface;

- do not increase the slipperiness of the road surface, especially when using PGM in the form of solutions;

- be technologically advanced during storage, transportation and use;

- not to increase the environmental load on the environment and not to have a toxic effect on humans and animals;

- do not cause an increase in the aggressive effect on metal, concrete, leather and rubber.

d) The properties of chemical PGMs are evaluated according to a number of indicators combined into four groups: organoleptic, physicochemical, technological and environmental, the main requirements for which are given in Table 2.

table 2

Requirements for chemical anti-icing materials used to combat winter slipperiness on bridge structures

The name of indicators
Organoleptic:
1. Condition	Granules, crystals, flakes	Aqueous solution without mechanical inclusions, sediment and suspension
	White to light gray (light brown, light pink allowed)	Light, transparent (allowed with a slight yellow or blue color)
		None (for settlements)
Physical and chemical:
4. Grain composition, %
Mass fraction of particle size:
Over 10 mm	Not allowed
over 5 mm up to 10 mm incl., no more
over 1 mm up to 5 mm incl., not less than
1 mm or less, no more
5. Mass fraction of soluble salts (concentration), %, not less than
6. Crystallization start temperature, °С, not higher
7. Humidity, %, no more
8. Mass fraction of substances insoluble in water, %, no more
9. Hydrogen index, units pHIf the payment procedure on the website of the payment system has not been completed, cash funds will NOT be debited from your account and we will not receive confirmation of payment. In this case, you can repeat the purchase of the document using the button on the right. An error has occurred The payment was not completed due to a technical error, funds from your account were not written off. Try to wait a few minutes and repeat the payment again.