Warranty period of operation of asphalt concrete pavement. Asphalt concrete pavement: general information

Asphalt laying is a rather complicated and time-consuming process, but at the same time an effective way of paving. The range of work performed includes: excavation, foundation, asphalt laying, landscaping.

The work performed at a professional level will allow you to create not only a reliable and stable road surface, but also ensure its long-term service life. Specialists START CITY GROUP will help you choose the best option for the base and material for laying asphalt, based on your wishes.

Characteristic

Asphalt (or asphalt concrete mixture) is a rationally selected mixture based on mineral materials, which include sand, crushed stone, mineral powder, liquid bituminous substance. All substances are selected in the optimal amount and mixed in a heated state.

Crushed stone, which is part of the mixtures, must comply with the requirements of GOST 8267 and GOST 3344. It is allowed to use gravel or crushed stone produced according to foreign standards, provided that their quality complies with established Russian standards.

The scope of application of asphalt concrete is wide: the construction of roadways, squares, sidewalks, parking areas, park areas for cyclists, airfields, flooring in industrial buildings and many other areas.

Today, asphalt concrete mixtures, depending on the mineral component, are divided into:

• sandy;
• crushed stone;
• Gravel.

The structure of each type has its own characteristics, which determine the effectiveness of the use of the selected material.

Also, asphalt concrete mixtures are classified depending on the size of mineral grains:

• Fine-grained - less than 2 cm;
• Coarse-grained - up to 4 cm.
• Sandy - up to 1 cm.

The amount of solid filler in the mixture depends on which group the asphalt concrete belongs to. There are 3 groups: A, B, C.

Stacking technology. Stages. materials

To date, two technologies for the construction of the roadway are used:

• hot asphalting;
• cold asphalt.

Each of them has its pros and cons:

• Hot asphalt. The mixture is prepared from viscous and liquid petroleum bitumen. Laying can be carried out in winter. The temperature of the mixture should not be less than 120 degrees. Before asphalt is laid, a piece of the road, on which the asphalt concrete mixture will be applied, is dried with special equipment.
• Cold paving. The mixture is prepared from liquid petroleum road bitumen. Laying works are carried out only in the warm season, since this technology does not dry the water. Cold asphalting is often used for patching.

Professional paving works require significant financial investments. After all, for this it is necessary to attract special equipment and experienced qualified specialists.

Asphalt laying consists of several stages:

1. Development of design estimates

Each site is individual: it has its own size, topography and configuration, soil characteristics, remoteness and features of access roads. Based on these criteria, after the departure of the specialist, the total area, volume and preliminary cost of the work are determined.

2. Territory development, excavation

Preparation of the territory for the installation of an asphalt canvas begins with the removal of the top layer of soil. As a rule, bulldozers and loaders are involved to remove a large soil layer. Graders are used to level the surface of the base. According to the given marks, the formation of a road "trough" is carried out with its further compaction.

If there is an old coating on the asphalted area, then it is destroyed by a road mill. With proper recycling, the old coating can be reused.

3. Foundation preparation

It is the turn of the formation of a "road pillow". To do this, two layers of the road “pie” are poured: first, sand or a sand-gravel mixture is laid, and to give the entire coating special strength, crushed stone of a large fraction is poured on top, and then a fine fraction is poured to minimize voids. Each layer of the base is leveled by a grader and carefully compacted. A side stone is installed along the edges of the site. In order for asphalting to be of high quality, before laying asphalt, the surface of the site is shed with bitumen.

4. Asphalt paving

The final layer consists of asphalt concrete. This material is delivered by dump trucks or is prepared directly on the road construction site itself. The standard composition of ABS includes: mineral powder, sand, crushed stone and liquid bitumen.

The mixture is evenly distributed over a given area. For laying the last layer of the mixture, asphalt pavers are used. Asphalt rolling is carried out by several rollers for the best consistent compaction. Our company has formed its own material basis - a modern fleet of special equipment, which has about 40 units of equipment, which fully ensures the entire process of road construction.

It should be noted that the technology of laying asphalt concrete and the materials used may have some differences depending on further operating conditions. So, for example, to extend the life of highways, new technologies are used - modified gel-like petroleum bitumen (MAK bitumen).

Road time

It should be noted that asphalt paving is a seasonal work and directly depends on weather conditions. It is recommended to carry out all work in dry weather.

In autumn and spring, the temperature should not be less than +5 degrees. After all, the delivered mixture is a hot product. Therefore, all manipulations with it should occur as quickly as possible so that it does not have time to cool. Otherwise, it will be impossible to lay asphalt.

Service life

The service life of an asphalt pavement directly depends on the loads, traffic intensity, weather conditions, adherence to laying technologies and the quality of the materials used.

The guaranteed service life is approximately 7 - 10 years. But you need to take into account the fact that with intensive use, the specified period can be reduced. Timely repair work of the roadway, which includes the elimination of pits, subsidence, cracks and irregularities, will help to extend the operational life.

RIAMO - 1 Dec. Asphalt pavement on roads in the center of Moscow lasts at least three years, said Alexander Oreshkin, head of the state budgetary institution (GBU) Highways.

“The warranty period for asphalt on central Moscow streets is three years. But this does not mean that we necessarily renew the asphalt when the warranty ends. The inclusion of the road in the repair plan depends on its condition. And this is influenced by the weather and the congestion of the street, ”Oreshkin said in an interview published on Friday on the official portal of the mayor of the capital.

He added that every spring experts monitor the road network and if they come to the conclusion that the asphalt can lie for another year, no one changes it. The warranty period on less busy routes can be up to four or even five years.

“For example, what is the point of changing the road surface more often in a small lane where one car passes every ten minutes? There he can lie quietly for six years without repair or replacement, ”Oreshkin explained.

According to him, the State Budgetary Institution "Highways" in the field of introducing new technologies mainly cooperates with the Moscow Automobile and Road State Technical Institute (MADI). The developments are further used not only in Moscow, but also in other cities of Russia. In MADI, the institution has its own laboratory for testing the quality of freshly laid asphalt.

“All the asphalt we lay in Moscow is produced locally. Today, 10 asphalt concrete plants and one cement-concrete plant operate in the capital. They were built in the last four years. They are the best in the world in terms of environmental safety. All the latest asphalt compounds have been developed by Russian scientists. In the repair of roads, we have nothing to learn from the West, I assure you, ”Oreshkin emphasized.

He also added that in the capital more than four years ago they began to use polymer-bitumen binder mixtures when laying the top layer of asphalt. They were designed specifically for the climate of Central Russia. They are used on central streets, ring and outbound highways.

“The basis of such mixtures is gabbro-diabase crushed stone. This is a volcanic rock, similar in mineral composition to granite, it is mined in Karelia. The material is not afraid of frost and has high strength (1.4 thousand kilograms / square centimeter). The use of a mixture based on gabbro-diabase crushed stone when laying asphalt increases the wear resistance of the roadway, minimizes dips and subsidence. The polymer component holds the crushed stone together and makes the coating even stronger,” concluded Oreshkin.

The most commonly used asphalt concrete mix for the construction of the top layer of the pavement on roads with high traffic intensity is crushed-stone-mastic asphalt concrete, produced in accordance with GOST 31015-2011 (ShMA-20). Due to the high content of rationally selected fractional crushed stone, including along the screening boundaries, a more stable skeletal structure is formed in it, thanks to which the SMA layer perceives loads better and shows good resistance to operational deformations.

Under dynamic and thermal loads and deformations, it is the quality of the binder that ensures the creation of a "monolith" that has all the required performance characteristics. In our opinion, very little attention is paid to the quality of the original bitumen and checking the characteristics of a / b for crack resistance and shear resistance at low temperatures and water saturation, including after freezing and thawing, resistance to the formation of plastic rutting.

A logical result is a high risk of non-compliance with the warranty periods of operation during construction and repair and seasonal restriction of the movement of trucks "to dry", that is, additional losses for all subjects of the Russian economy. Consider our step towards solving this problem.

The use of bitumen obtained by oxidation technology, which meet the requirements of GOST, as practice shows, does not provide the required durability of road surfaces. The main reason for this is the insufficient deformability of oxidized bitumen, poor adhesion to mineral materials (especially acidic ones), and low resistance to aging processes. Asphalt concretes made on the basis of non-oxidized bitumen have hydrophobic properties, and hydrophobicity is already directly related to water resistance. In turn, increased water resistance increases the durability of the pavement.

Based on the well-known principle that the property of asphalt concrete is determined mainly by the quality of bituminous binders, researchers and road practitioners in many developed countries have come to the conclusion that it is expedient to replace conventional bitumen with polymer-modified bitumen (BMP).

Starting from the 60s, this area of ​​bitumen technologies has been developing quite intensively, but haphazardly: various polymers were used (at the first stage, production waste), there was a search for technologies for their optimal combination with bitumen. Thus, the scientific and production experience accumulated up to this time indicates the advantages of asphalt concrete based on polymer-modified bitumen, compared to conventional asphalt concrete, in terms of: strength and, in particular, shear resistance; brittleness and crack resistance temperatures (with appropriate polymer content); stability in the aquatic environment and, ultimately, the durability of asphalt polymer concrete pavements. At the same time, the provision of these advantages requires the complication of the technological preparation of bituminous binders, which leads to their rise in price due to the high cost of polymers. At the same time, a significant additional consumption of energy resources is inevitable, which is necessary for carrying out all technological processes at temperatures 15-25 ° C higher than in the case of the practice of using traditional bitumen and asphalt concrete. Compensation for the costs of application can be ensured by lengthening the time between repairs of the asphalt-polymer concrete pavement and reducing the volume of its repair.

Developing in a given direction, Innovative Technologies LLC conducted a set of laboratory studies and full-scale practical tests in the period from 2013-2016, as a result of which the possibilities and requirements for the use of the Dorflex BA® material were determined. The polymer modifier "Dorflex BA" is a bulk material in the form of granules with a diameter of 2-6 mm. Secondary polymers - polyolefins modified with organoelement compounds - are used as feedstock for Dorflex BA composition.

The increase in the durability of road surfaces is determined by the ability of the top layer of the road surface to perceive static and dynamic loads in all operating conditions without destruction and deformation, this is achieved by increasing the cohesive strength of the adhesive of the binder with asphalt concrete and maintaining its "elasticity" to the maximum.

Butadiene and styrene thermoplastic elastomers of the SBS type, the most common in road construction, are distinguished by the ability to highly elastic deformation due to the work of a spatial structural network formed due to physical bonds between blocks of butadiene and styrene macromolecules. With the use of the modifier "Dorflex BA", an increase in the resistance of asphalt concrete to shear deformations occurs, associated with the formation of a spatial polymer structural network in a bituminous binder, close to that obtained using a polymer-bitumen binder (PBV). Physical and mechanical characteristics on the example of ShMA-20 modified with the additive "Dorflex BA" in comparison with the reference brand of the mixture are shown in the table.

Table Physical and mechanical characteristics of crushed stone-mastic asphalt concrete ShMA-20.

The use of secondary polymers as a modifier in road construction solves the problems of increasing the thermal stability of asphalt concrete, saving bitumen, recycling solid domestic waste, as well as related environmental problems and environmental protection. The mechanism of the modifying effect of the additive on road bitumen, as part of an asphalt concrete mixture, consists in filling the mass of bitumen with a finely dispersed polymer phase, that is, in structuring. Naturally, with an increase in the degree of filling of the binder mass with a dispersed polymer phase, the cohesive strength and density of the composition increase. Since the basis of the modifier is a thermoplastic linear polymer - polyolefin, which makes the bitumen-polymer system sufficiently rigid, as evidenced by a sharp increase in the viscosity of the modified bitumen, it can be assumed that the abrasive effect of solids on the surface of the polymerized bitumen-polymer system (wear from studded rubber) does not will have a destructive effect on the molecular bonds of the latter.

The duration of the preparation of the asphalt concrete mix does not change, thereby maintaining the productivity of asphalt concrete plants and eliminating the need for significant costs for the installation of additional equipment. The dosing of Dorflex BA can be done manually or automatically by means of a dosing device consisting of a small hopper for the granular modifier, a screw conveyor and a weighing batcher. The temperature of a traditional asphalt mix using Dorflex BA at the outlet of the mixer should be in the range of 150-155 °C, of ​​a crushed stone-mastic mixture 160-165 °C.

Together with NCC-road, studies were carried out to find the optimal composition of asphalt concrete mixtures using Dorflex BA and a series of comparative tests were carried out with different content of the polymer additive in the preparation of asphalt mixtures with their subsequent compaction during the operation of the road surface on the test site. It has been established that the most effective summation of technical and economic factors for SMA and hot mix asphalt is the content of "Dorflex BA" in an amount of about 0.2% of the mineral part of asphalt concrete. A scientific and technical research base has been formed, design and technological documentation has been developed for the use of Dorflex BA as a modifying additive for hot asphalt mixes of all types.

To confirm the theoretical data, and determine the effectiveness, tests were carried out for resistance to the formation of plastic rutting on the asphalt concrete pavement analyzer (APC), as well as tests for wear resistance from studded rubber by the Prall method according to SFS-EN 12697-16.

As a result of tests for rutting, it was found that the modifier "Dorflex BA" significantly reduces the susceptibility of asphalt concrete to plastic deformation. A comparative analysis of the results showed that the values ​​of the track indicators when using Dorflex BA are close to the values ​​when using PBB 60.

Due to the introduction of the modifier into the asphalt concrete mix, an improvement in wear resistance indicators is recorded on average by 5-7% from the reference grades of mixtures according to GOST 31015 and GOST 9128. If we analyze the results of the wear resistance of asphalt concrete according to the Prall method (SFS-EN 12697-16), with the characteristics of reference mixtures, the modifier practically increases this indicator by one class.

Summarizing the above, we propose to pay attention to the modifying additive "Dorflex BA", we are sure that our work will reduce the likelihood or completely eliminate cases of non-compliance with the warranty period for the operation of the roadway.

A.V. Ivkin,
Technical Director
LLC "Innovative Technologies"

For the past month, we have been trying to convince the city administration to increase the guarantee for road repairs. Despite the obvious advantages of the increased warranty for the city, we were faced with a powerful road lobby. From the public chamber of the city, a letter was sent to Yakob with a request to increase the warranty period, he is convinced in every possible way that this is not possible, but in fact everything is possible. Until May 12, it is possible to make changes to the auction documentation for road repairs in the amount of 434 million rubles, and increase the guarantee from 3 to 5 years.
Within the framework of the Public Chamber, they did everything they could, but it is not possible to increase the guarantee. So far, we have achieved an intermediate result - an increase in the guarantee from three to four years, and then from next year. This option does not suit me, and I want to win over the townspeople and the media. Therefore, I ask journalists for help in covering the topic of warranty periods for road repairs. We need a comment from the administration so that they explain why they do not increase the guarantee for road repairs. Next, there will be a rather long text with the cost of asphalt and with references to the orders of the Ministry of Transport - this is important to know in order to understand why we suddenly demand an increase in the guarantee.

Until 2013, all roads in the city were repaired with asphalt grade I Type "A" and contracts included a guarantee of 3 years. The cost of a ton of asphalt type "A" in 2001 prices is 497.88 rubles per ton without VAT. Starting from 2013, we switched to ShMA asphalt, which costs 735.75 rubles per ton.

Using more expensive ShMA asphalt, within a limited budget, we reduce the area of ​​roads being repaired. If you do not increase the warranty period, the city takes on an additional burden. In the current realities, I think this is not reasonable. Moreover, if the ShMA asphalt was laid poorly, then in three years it is not possible to fully understand this, because. it resists wear better than grade I type "A".

Moreover, the order of the Ministry of Transport of the Russian Federation No. IS-414-r dated May 7, 2003 No. prescribes the following warranty periods:

Therefore, the warranty can be from 4 to 12 years, for asphalt grade I type "A". The mayor of Polevskoy put a guarantee of 5 years.

Personally, I don’t understand at all why the administration has not increased the guarantee on its own until now. And the only explanation for this I see in the actions of the road lobby.
In fact, in most cases, the formation of ruts and pits is not due to spikes, but due to a violation of technology or poor quality asphalt. Here are three examples of streets where cheaper grade I type "A" asphalt was used.

1. Lenin Avenue from March 8 Street to Karl Liebnecht was renovated in 2012, traffic intensity is more than 30 thousand cars a day, asphalt has been standing for four years, and no climate, spikes or tanks can destroy the road.


The only area where a rut formed and the top layer of asphalt was worn out: in front of the intersection since March 8, but there the rut was formed due to the fact that instead of a layer of asphalt 10 cm thick, only 3.5 cm were laid.

2. Mamin-Sibiryak Street, asphalt was also laid in 2012, already in the fall, a couple of days before winter. The intensity of traffic is 20-30 thousand cars per day, asphalt has been standing for four years, and I am sure that such a road will stand for 12 years without major repairs.

And here is the Tokarey-Gurzufskaya-Repina-S. Deryabina junction, the new, newly built road fell apart after 4 years, the photos were taken in 2015, now it’s even worse. This interchange was built by Trust UralTrasSpetsStroy, which is now breaking through Lenin to Tatishchevo.




For four years, both the upper layer and the lower one fell apart on the new road, there was a three-year warranty! You see the "cobweb", usually contractors say that this is not a warranty case and the pillow is to blame. How could a pillow go bad in 4 years?

Have you ever seen a new road in Europe fall apart in 4 years? The main cause of bad roads is not in the thorns or the climate, but in the hands of the road builders - they just don't know how to fix the roads. It’s like a gastrobaiter who has been laying tiles crookedly for 10 years, he has a lot of experience in spoilage, but normally, according to GOST, he will no longer be able to lay tiles, well, or he will be able to lay if he constantly creates an atmosphere of anxiety.

Therefore, if we are talking about improving the quality of roads, we need to start with an increase in warranty periods and operational control, that is, in the summer, make sure that asphalt is not laid in puddles even in the rain. If we don't do it ourselves, no one else will!

A request to the residents: please spread this post on your social networks, it will suddenly help and the guarantee will be increased!