Recommendations for the correct installation of curbs. The list of asphalt defects, the causes of their occurrence What does the local destruction of the side stone mean

The use of new technologies and materials in the construction of roads is experienced by every car owner. It is impossible not to notice that the quality of roads is improving every year, and the BiK company makes a significant contribution to this process.

Why is the roadbed being destroyed?

The most common answer to this question is climate. But blame it all natural conditions not very correct, since on our planet there are a huge number of countries with a cold climate and good roads.

The rapid wear of the road surface is primarily affected by the quality road works. If the pavement is laid using low-quality materials, in violation of laying technologies, with inaccurate calculations of the pavement thickness, then the reasons for the rapid wear of the roads become obvious.

The main types of destruction of the roadbed

• wear or abrasion - occurs under the influence of the pressure of automobile wheels and climatic precipitation;
• peeling - manifests itself in the form of exposure of sections of the road surface as a result of frequent freezing and thawing of asphalt, and de-icing reagents can also provoke peeling of the coating;
• chipping - manifests itself in the form of losses of crushed stone and gravel fractions.
• potholes, ruts, shifts, cracks, dents - the main cause of such damage is road work performed in violation of the technological process.

How to keep the road surface from wear and tear for a long time?

As mentioned above, the main road works- this is the high quality of the material and the accuracy of the observance of laying technologies.

"BiK" uses in its work a variety of techniques and materials designed to improve the quality and durability of the road surface. We use special emulsions to increase the impermeability of the pavement, lay geotextiles between the layers of the road, and also produce pavement with poured asphalt.

But once well-executed road work is half the battle in maintaining the integrity of the roadway. It is necessary to regularly monitor the further condition of the road surface, because the earlier the destruction is detected, the easier and cheaper it will be to carry out repairs.

Today, information appeared in the Krasnoyarsk media that curbs installed last summer on Partizan Zheleznyak Street were destroyed. What affects the strength of the curb stone, and why are seemingly whole curbs sometimes replaced? Our correspondent talked to experts and found out the answers to these questions.

Vadim Servatinsky, Head of the Department of Roads and Urban Structures at the Institute of Civil Engineering of the Siberian Federal University, answers the question why a good curb needs to be changed: “You don’t need a good one. But the whole line of curbs is not good.” It is worth saying that there are no GOSTs on the terms of the mandatory replacement of concrete curbs. The decision is made based on the condition of the curb stone. And he, according to experts, can quickly become unusable. The curbs are starting to crumble different reasons, and the most common of these is mechanical damage. As a rule, everything begins in winter, when the streets are cleared of snow. A large grader rests with a heavy metal blade on the curb, and on the surface artificial stone scratches appear, the destruction of the protective layer of the frontal part begins. Such borders, of course, need to be replaced.

The destruction of a concrete curb can also occur due to insufficient frost resistance, since this element of the road infrastructure is reinforced only with anti-shrink reinforcement, and not with a working one that carries the load. To maximize the service life of curbstones, compliance with stringent placement requirements. The stones must either be set on well-compacted ground or be joined together. concrete screed. There is no other way, because, on the one hand, the curbs perform the protective function of wheel rebound - to increase traffic safety, on the other hand, they create a single monolithic road space. But it is for this reason that if one element is damaged, the entire line has to be changed.

“Technologically, it is very difficult to remove only one curb stone in order to put another one in its place,” Vadim Servatinsky emphasized. “Therefore, their replacement is carried out on a planned basis and in large quantities: even if only one element is damaged, the entire line of curbs on the street is removed, and new blocks are installed in their place.

But it is impossible to use a monolithic curb tape made of concrete, since for this element of the road it is necessary to leave expansion joints. Indeed, in the summer, in the heat, the curbs expand, in the winter their size is reduced. The width of the gaps depends on the size of the curbstone itself, according to GOST it ranges from one to one and a half meters. Borders are not only made of artificial stone - concrete, but also of natural. In the central part of Krasnoyarsk, expensive granite curbs have been installed on a number of streets. They do not lose their strength properties upon impact. When repairing the street, they are pulled out and then installed back. But the sidewalks are not fenced with curbs, but with curbs, the thickness of which is up to eight centimeters. Curbs are designed to limit the width of the sidewalk, keep the asphalt within the required limits and keep the pedestrian or cyclist. As a rule, the curb is exposed from the side of the lawn. It prevents soil from washing onto the pavement in the event of heavy rains.

Pits, potholes, chips, subsidence, breaks, shifts, cracks and rutting - all these defects inevitably occur 2-3 years after the introduction of a new highway into operation or capital reconstruction old section of asphalt concrete road. The formation of all defects and damage to the asphalt pavement is due to a whole range of various factors that can occur not only during the operation of the road, but also occur at the stage of its design and construction.

As a rule, the problems that caused the destruction of asphalt concrete pavements have their own solutions. They differ in terms of cost, but, in the vast majority of cases, they turn out to be effective and justified in terms of financial investments in the longer term.

At the present stage of development of the global road construction industry, there is a fairly wide range of technologies and effective ways solving problems associated with premature destruction and wear of road surfaces. Depending on the specific causes affecting the process of degradation and destruction of the roadway or potentially capable of having such a negative impact in the future, appropriate measures are taken to eliminate them or minimize the negative consequences of their impact. Such measures may include both the application of the most modern materials at the stage of creating a road structure (soil stabilization, the use of geomaterials and reinforcing geogrids, asphalting roads using modified asphalt concrete mixtures, etc.), as well as regular preventive and road repair work during road operation.

Causes of destruction of asphalt concrete pavement

All factors affecting the process of damage formation asphalt concrete pavement conditionally can be divided into internal and external. Internal factors are related to the design, construction and maintenance phase of the road, while external factors have a more indirect relation to the subject of influence and are determined by external negative influence on the asphalt pavement during its operation.

1. Errors in the design of the road

Errors in geodetic and hydrometric surveys, miscalculations in the design and installation of drainage, incorrect assessment of the growth of the throughput of the route - all this can cause serious violations of the integrity of the road structure in the form of subsidence of the soil base, washing out and reducing the stability of the underlying soil base, rapid wear of the road surface and other defects.

2. Outdated technologies and low-quality materials for asphalt paving

The necessary transport and operational indicators of the highway (basic capacity, allowable vertical axial load, maximum allowable speed, etc.) are achieved during its construction and depend on the construction technology and the road construction materials used. Until recently, when asphalting, building, repairing and reconstructing asphalt concrete roads, hot compacted asphalt concrete mixtures prepared on the basis of ordinary petroleum bitumen of the BN or BND grade were most widely used. The low quality of such bitumen often leads to a decrease in the characteristics of the finished asphalt mix and causes rapid wear and destruction of the road surface, which manifests itself in the form of cracks, chips, pits and potholes.

To date, developed and effectively applied a large number of new polymer-bitumen binders, which significantly increase specifications asphalt mixes and, ultimately, the characteristics of the road surface itself. There are also various adhesive additives and additives for asphalt concrete mixtures that improve the adhesion of the binder component to the mineral filler, slow down the aging process of bitumen under temperature changes, increase water resistance, crack resistance and frost resistance of the road surface.

In addition to the use of new asphalt mixtures for the construction of the upper layers of the road surface, it is also advisable to use modern technologies to stabilize weak and moving soil bases, the use of synthetic geomaterials to strengthen and stabilize sandy and crushed stone bases, the use of a reinforcing geogrid to reinforce the asphalt concrete layers of the road structure. All these technologies and materials will help to significantly increase the life of the asphalt pavement.

3. Violation of technologies and rules of work during the construction of the road

Failure to comply with regulatory requirements and rules during construction, asphalting and road repair is the factor that will inevitably affect the process of pavement destruction.

Thus, violation of the simple rules for transporting the asphalt mix to the place of laying leads to its cooling down to temperatures below the required ones, which already violates the technology of work associated with asphalting. Laying hot mix asphalt at an ambient temperature below +5°C, insufficient compaction or overconsolidation - all this causes cracks, chips, delamination and other defects to form on the road surface.

The formation of defects on the pavement surface is not necessarily associated with technology violations at the asphalting stage, but may be the result of poor quality work during the installation. subgrade and underlying layers of the road structure (sand and gravel base). Thus, the consequence of insufficient compaction of the subgrade is the vertical subsidence of the road surface without the formation of cracks (occurs due to deformations of the subgrade soils and materials of the structural layers of the road pavement). Such defects are eliminated, as a rule, by patching, which makes it possible to eliminate the formed defects on the asphalt road surface. Pothole repair of asphalt is carried out in case of inexpediency of the device of a new continuous surface layer, when the entire problematic section of the road is asphalted.

4. Weather conditions

The most intensive formation of defects on the asphalt concrete pavement occurs in spring and autumn, when, due to moisture penetrating into the road layers and ambient temperature, their strength characteristics decrease, which contributes to the formation of damage in the form of potholes.

A high degree of humidity in the structural layers of the road when the ambient temperature drops below 0 ° C leads to the destruction of the asphalt structure and the decompression of the earth, sand and crushed stone base. This happens due to an increase in the volume of moisture in the process of transition from a liquid to a solid state upon freezing. The solution to this problem lies in the use of modern asphalt concrete mixtures based on PBB (polymer-bitumen binders) and other polymer-bitumen composites that prevent moisture penetration and have a wider operating temperature range.

5. High traffic load

Rapid growth in the number Vehicle leads to an increase in traffic intensity and an increase in the design capacity of the highway. As a result of exceeding the daily throughput capacity of the route, the resource of the road surface is rapidly declining. Another negative factor is the increase in the carrying capacity of vehicles, as a result of which the axial load on the road surface increases. The consequence of this is the formation of rutting, shifts and cracks. A natural result of the appearance of such defects is a decrease speed limit on a separate section of the road. Damage resulting from traffic loads (cracks, pits, chips, potholes, etc.) in turn reduces the water resistance, strength, evenness and adhesion properties of the coating.

The destruction of asphalt concrete road surfaces occurs as a result of a complex impact such factors as: miscalculations in the design of the highway, the use of outdated technologies and low-quality materials in the construction of the road, violation of technologies and rules for road construction, adverse weather conditions, as well as an increase in traffic load.

Measures to prevent the destruction of asphalt concrete pavements

The solution to the problem of pavement destruction lies in the application of complex, rather than partial measures. So, timely treatment of a small crack with a bituminous mixture will help slow down the process of formation of a fault and a large pothole, but this does not solve the problem underlying the appearance of these cracks. The situation is similar with such types of damage as rutting, breaks, shifts, etc. First of all, it is required to eliminate the cause of the resulting damage, and not its consequences.

Effective solutions that will help ensure the long-term maintenance of the required transport and operational indicators of the road, maintain the integrity of the road surface and increase its service life are:

• Application of modern technologies and new materials when asphalting roads and laying the underlying layers of the road structure (soil stabilization, the use of geosynthetics, asphalting with the use of polymer-asphalt-concrete mixtures based on PMB). Currently, wide application find modified asphalt mixes that have reduced temperature sensitivity of the binder and elasticity road material, which provides increased heat resistance in summer period, a higher ability to generate thermal cracks in winter and fatigue cracks during road operation.
• Strict observance of all regulatory requirements and rules during the production of road works.
• Regular maintenance and repair work. Delays in carrying out road repair work lead to a deterioration in the condition of the road and require additional costs in the future to bring them into a standard condition. Late road repairs require thicker layers of pavement reinforcement and delays of three years require twice the cost of pavement repairs.

Patching and overhaul of asphalt in Kyiv and Kyiv region

The Unidorstroy enterprise carries out high-quality carrying out of all complex of works on repair and restoration of asphalt concrete road coverings. Carrying out patching of asphalt as soon as possible, services of full restoration and reconstruction of the road surface.

snowmelt and during rain, surface water lingers on the surface and partially penetrates down. On the footpaths standard projects there is no provision for water intakes. In spring, most often, the sandy layer is in a waterlogged state due to the lack of tubular drains to drain it. Under the influence of the movement of harvesters, water is mostly squeezed out through the cracks. Currently, more and more often on sidewalks and footpaths, a coating of prefabricated concrete slabs with a thickness of 5-6 cm is used, often laid directly; on sand (and even fine). In this case, the cracks formed during the thawing period are due to its insufficient strength. When the cleaning machines move in the slabs, a significant overvoltage occurs, which causes their premature destruction.

Side stones. The main deformations of the side stones, which result in the need for their complete replacement or rearrangement, are the following reasons: insufficient frost resistance of the concrete itself; frosty uneven heaving with dusty subgrade soils; change in the vertical position of the side stone; destruction of the concrete horizontal part of the long side stone. If on boulevards, dividing strips or lawns, the mark of the vegetation cover is 15-20 cm higher than the surface of the side stone, then in areas with severe weather and climatic conditions with dusty subgrade soils, the side stone is usually inclined to the axis of the street. This is due to the formation of ice lenses and interlayers parallel to the surface of the side stone as a result of heat loss.

The temperature incompatibility of cement concrete with asphalt concrete is accompanied by chipping in a few years along the side stone of the asphalt concrete pavement. A gap is formed through which surface water penetrates. Later in winter period stone or concrete slabs laid at the junction of the side stone with the coating are subjected to frost heaving; periodically they have to be shifted or replaced. A significant defect of the concrete side stone is the peeling of its surface. Concrete is a heterogeneous capillary-porous body with a large number of phase boundaries. From the moment of hardening of concrete, defects in the form of voids are noticeable in its structure. The weakest point of the concrete structure is also the contact zone of hydrated neoplasms of the cement stone. The contact zones between cement stone and aggregate are especially prone to cracking. Different coefficients of linear expansion in these zones with temperature fluctuations near the surface of the concrete wall cause microstructural stresses exceeding the critical ones. In concrete with crushed stone, especially from limestone even of the 1st class, there are a significant number of open pores and capillaries. These pores are filled with water from autumn, which freezes at a temperature slightly below 0 ° C and contributes to the initial desquamation process. The service life of a concrete side stone, subjected to a more severe steaming regime during its manufacture, in the central regions of the European part of Russia very rarely exceeds 10 years. However, curb stone made of sand concrete, in which micro- and ultra-micropores predominate, is more frost-resistant than stone aggregate. Water in micropores freezes at much more low temperatures, without calling in the initial