RU2473728C1 - Road pavement for motor roads and aerodrome pavements - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: in the proposed road pavement a slabby cover is arranged with inclination of a slab pack along the road surface at the angle from ±1 to ±3 degrees to the horizon, besides, the gap between ends of joined slabs is selected within 3 to 7 mm; the road pavement base is made from a popcorn encapsulated cement concrete, made from a dense rubble filler with a grain size from 5 to 40 mm. The base concrete layer is also arranged on side surfaces of a soil prism to its lower part; between a pre-cast cover from pre-stressed reinforced concrete boards and an upper layer of the base there is a levelling layer from sand strengthened with cement with thickness from 20 mm to 50 mm, and between the strengthened soil and the lower layer of the base there is a geotextile grid.

EFFECT: higher resistance of a coating.

1 cl, 3 dwg

Description

The present invention relates to the construction of pavements for roads, airfield and site coatings, as well as similar structures that undergo significant temperature fluctuations and high drainage efficiency requirements during operation.

Known road clothing, including a two-layer coating, and the upper coating layer consists of dense asphalt, and the lower layer is made of porous asphalt concrete; and a multilayer base consisting of a drainage layer and two layers of supporting material: a layer of black gravel and a layer of fractionated gravel (see, for example, RF patent No. 2399715, class E01C 7/00, 2009). Moreover, the thicknesses of the layers of the pavement are selected in accordance with the thickness and density of the upper layer of the asphalt concrete pavement according to a certain patented functional dependence, derived by calculation based on the optimal ratio of the natural frequencies of the layers of the pavement, taking into account the inertia of the layers and the process of development of vibrations from top to bottom in the road structure.

The selection of the optimal ratio of the thicknesses of the layers in the known construction of the pavement allows to reduce the level of vibrational forces in the layers of the pavement and thus increase the performance and durability of the pavement.

In another known construction, pavement includes a base from a densely rolled drainage layer and a crushed stone layer of low-strength limestone or gravel, as well as a layer of coarse-grained asphalt concrete, and a coating of asphalt concrete with a surface treatment layer of black crushed stone - klinets up to 10 mm in size ( see, for example, RF patent No. 2332535, class E01C 7/18, 2006). Moreover, a bitumen-claydite composition with a thickness of 60 mm is used as an asphalt concrete coating mixture, and expanded clay sand of a fraction of 0.14-5.0 mm in an amount of up to 70 wt.% Is taken as expanded clay aggregate.

This design of the pavement, providing satisfactory water permeability of the drainage layers, at the same time, due to the use of expanded clay aggregate in the coating, significantly reduces the thermal conductivity of the road structure, its density and weight, as well as the coating thickness.

However, in the above known constructions of pavement due to insufficient deformability and frost resistance of asphalt concrete at low temperatures, the actual service life of coatings is often lower than standard. At the same time, due to the constant increase in freight traffic on the roads, the emergence of new types of vehicles with increased axle loads, intense rutting and destruction of asphalt concrete pavements of roads is observed. In one of these known solutions (see US Pat. RF No. 2332535), in order to increase the stability and crack resistance of the pavement, a drainage layer is provided under the asphalt concrete base layer for water drainage. However, this layer is rolled during installation of the road structure, which significantly reduces the efficiency of its use and, as a result, the effectiveness of the application of the known solution as a whole.

Pavement is also known, including prefabricated slabs (concrete, reinforced concrete, prestressed reinforced concrete, cast slag, etc.) laid on a base of compacted sand, gravel, gravel material of optimal composition and soils reinforced with cement or bitumen (see, for example , the book of VM Mogilevich and others. Prefabricated road coverings. - M.: Higher School, 1972. - S.216-223). Concrete and reinforced concrete slabs made of concrete of high grades (“500” and higher), as well as prestressed concrete slabs, can withstand the stresses arising from the loads of moving heavy vehicles, therefore, such slabs can be used for almost all types of prefabricated coatings. In addition, the use of slabs for collapsible pavement provides the possibility of repeated dismantling and subsequent restoration of the pavement.

However, due to the penetration of surface moisture into a sandy, gravel, or gravel base through seams between plates and groundwater, its overmoistening occurs through the base itself, while the density and strength of the base decreases, its contact with the lower surface of the plates is broken, and under the influence of heavy movement, the plates shift relative to each other, their uneven subsidence, broken edges of the plates, which ultimately leads to the destruction of the slab coating.

The closest in technical essence to the proposed one is pavement for roads and airfield coatings, including a prism made of reinforced soil, a base and a cement concrete coating made of prestressed reinforced concrete slabs fastened with steel reinforcing ropes with packages of shock absorbers in the slots of the slabs between them (see ., for example, Patent of the Russian Federation No. 2379406, class E01C 5/08, 2007). The fastening of the plates is carried out in one or two mutually perpendicular directions using through reinforcement from steel ropes, passed through the channels provided in the plates, followed by tensioning of the reinforcement with a force of 5 to 30 tf for each rope. Between the ends of the slabs, elastic elements are put on the ropes, and the ends of the ropes after tension are fixed by anchors in the fastening cavities of the extreme in the packs of plates with the subsequent monolithic of the cavities with concrete.

Due to the pulling of the plates into the road surface with steel ropes, it is possible not only to quickly install high-strength and durable surfaces in the conditions of the construction site, but any, even the smallest, displacement of them relative to each other is practically prevented, which significantly improves the performance of the coating and, above all, evenness. Movement on such a coating can be opened immediately after completion of construction. In addition, the installation of the known coating can be carried out year-round, and the main coating material - prestressed concrete slabs - are manufactured industrially at the factory and therefore are of high quality, thus ensuring high-quality performance of the mounted pavement.

However, slabs in well-known pavement at the joints are monolithic with sealant and laid on a low-permeable earthen or sand base, as a result of which water appears on the coating in the base. The presence of water on the surface of the coating significantly reduces the safety of traffic. Water lingering in the base during the winter period during freezing-thawing results in cracking in the coating and a decrease in the durability of the known pavement.

The purpose of the invention is to increase traffic safety, the exclusion of aquaplaning and the provision of drainage of pavement.

This goal is achieved by the fact that in road pavement for roads and airfield coatings, including a prism made of reinforced soil, a base and a cement concrete coating made of prestressed reinforced concrete slabs fastened with steel reinforcing ropes in packages with shock absorbers in the slots of the slabs between them, a slab coating made with a slope of the plate pack along the roadway at an angle of ± 1 to ± 3 degrees to the horizontal, and the gap between the ends of the joined plates is selected in the range from 3 to 7 mm; the base of the pavement is made of large-pore encapsulated cement concrete made of solid macadam aggregate with a grain size of 5-40 mm, and the base concrete layer is also placed on the side surfaces of the soil prism to its lower part; between the prefabricated coating of prestressed concrete slabs and the top layer of the base there is a leveling layer with a thickness of 20 mm to 50 mm from sand reinforced with cement, and a geotextile mesh is laid between the reinforced soil and the bottom layer of the base.

Given in the claimed pavement parameters of the manufacture of the road structure ensure the achievement of the goal. Outside the specified parameters, the goal is not achieved.

The essence of the proposed technical solution is as follows. The gaps between the ends of the mating plates with a size of 3 mm to 7 mm allow moisture to flow freely from the surface of the plates, given the slope of the surface of the coating along the road surface at an angle of ± 1 to ± 3 degrees to the horizon, and then removed through the proposed technical solution large-pore draining concrete base, characterized by a filtering capacity of more than 0.2 cm / s If there is a certain inclination of the coating web due to the terrain, there is no need to create a special inclination of the package of plates.

The high permeability of the used large-porous concrete from 0.2 to 2 cm / s is associated with a highly developed through porosity, which varies for encapsulated concrete from 35 to 45%.

The high drainage ability of the base provides a quick drainage of water from under the precast slab cement-concrete coating, which prevents decompression of the base, its frosty swelling during alternate freezing and thawing, thus ensuring close contact of the base with the bottom surface of the slabs and, consequently, the evenness of the roadway.

The pre-stressed reinforced concrete slabs provided in the claimed pavement, bonded to each other in long packages of slabs with high-strength steel ropes, in combination with the supposed removal of water through the gaps between the ends of the mating slabs and the drainage base from encapsulated crushed stone cement concrete, provide a durable, frost-resistant and durable clothing capable of withstanding the most severe transport loads for many years.

The design of the proposed pavement is shown in figures 1-3. In Fig.1 is a transverse section, in Fig.2 is a section along the packages of plates on the road surface; figure 3 (photos) - a) the end face of the slab of prestressed concrete with the fastening of the steel rope with an anchor at the end of the slab and b) the gap between the slabs with a shock absorber-seal during the tightening of the steel rope.

Road clothing contains a coating made of prestressed reinforced concrete slabs 1, laid end to end and pulled together by steel ropes 2 into long packages from 15 to 60 m long, and elastic elements, preferably rubber, 3 are worn between the ends of the plates 1 on steel ropes 2 in the form of cylinders with conical ends.

Between the plates 1, after tensioning the steel ropes, a gap 4 of 5 mm to 7 mm is provided. The carrier layer — the base 5 of the proposed pavement — is made of large-pore encapsulated cement concrete made of dense crushed stone aggregate with a grain size of 5 mm to 40 mm. Base 5 is mounted on prism 6 of cement-reinforced soil. Between the slab and base 5 there is a leveling layer 7 of sand with a thickness of 20 mm to 50 mm, which ensures the density and evenness of the laying of the slab on the crushed stone cement concrete base, creating an angle of inclination of the pavement along the road surface (from ± 1 to ± 3 degrees to horizon).

The leveling layer 7 of sand makes it possible to easily move the plates 1 in the process of pulling them with steel ropes 2 into long packages, as well as when the ambient temperature changes. To drain water in the claimed design of the pavement, a drainage is provided 8. In order to strengthen the slopes of the prism 6, a layer 9 of coarse-porous draining concrete of the same composition as the base is placed on its lateral surfaces. An interlayer of geotextile fabric (geotextile mesh) 10 is mounted on the upper and side surfaces of the soil prism to prevent siltation of the large-porous drainage concrete base. In addition to packages of prestressed plates, on the surface of the leveling layer 7 for roads there is a blind area 11.

Pavement erected as follows.

A prism 6 of reinforced soil with a drainage 8 is covered with geotextile 10 and the formwork 12 is exposed along the perimeter of the grab of the coating under construction. Encapsulated cement concrete is fed into the space between the formwork onto the prism surface covered with geotextile 10, which is leveled with a grader and compacted with a roller, creating a base 5 in the form of a layer of large-porous draining cement concrete with a thickness of 20-40 cm (depending on the calculated loads) made of encapsulated dense crushed stone aggregate with a grain size of 5 mm to 40 mm.

At the same time, in order to strengthen the slopes and increase the overall stability of the soil prism 6, a layer 10 of drainage cement concrete of the same composition as base 5 is laid on its lateral surfaces, which is connected to the base 5, and drainage 8 is arranged in the layer 10 to drain water from the pavement.

Stacked drainage concrete is closed for one to two days (depending on the ambient temperature) with a tarpaulin or a polymer sheet to prevent moisture loss and hardening of concrete.

On the hardened monolithic base 5 of encapsulated cement concrete, a leveling layer 7 of 20 mm to 50 mm thick is laid from sand reinforced with cement, according to which the method of laying back to back each other is applied to laying prestressed concrete slabs 1 in an amount of 5 to 20 pcs. for every package you collect. The laying of the plates 1 is carried out so that the through channels in the plates are placed coaxially and parallel to each other. Then, steel ropes 2 are pulled through the through channels, at the same time putting special cylindrical shock absorbers-seals on the ropes between the conical recesses with conical ends made of rubber or polyurethane, after which the plates 1 are pulled together with steel ropes 2, followed by tensioning of the ropes with jacks with a pulling force of 5 to 30 tf for each rope. At the same time, between the plates after tension leave gaps 4 of a size of 3 mm to 7 mm. Figure 3 shows the end face of the slab of prestressed concrete with the fastening of the steel rope with an anchor at the end of the slab.

Each package is laid on the base of the pavement with an inclination along the roadway at an angle of ± 1 to ± 3 degrees to the horizontal by adjusting the thickness of the leveling layer 7 (Fig. 2).

The proposed technical solution allows the most efficient use of the soil, planned and compacted into a prism, onto which successive layers of drainage concrete are laid, and on them sand plates are mounted on pre-stressed concrete slabs, which are pulled together in a single package - the blade disk.

The present invention allows to minimize the volume of crushed stone and sand, usually laid in the base of roads and airfield coatings, to reduce the material and laboriousness of construction.

The combination of a draining base and high-strength reinforced concrete slabs will allow to drastically increase the turnaround time and durability of new roads and coatings, and will allow the operation of motor vehicles and airplanes with heavy payloads without the formation of ruts and the need for "patching" repairs.

Claims (1)

Road clothes for roads and airfield coatings, including a prism made of reinforced soil, a base and a cement concrete coating made of prestressed reinforced concrete slabs fastened with steel reinforcing ropes to each other with packages of shock absorbers in the slots of the slabs between them, characterized in that the slab is tilted a package of plates along the roadway at an angle of ± 1 to ± 3 degrees to the horizontal, and the gap between the ends of the joined plates is selected in the range from 3 to 7 mm; the base of the pavement is made of large-pore encapsulated cement concrete made of solid macadam aggregate with a grain size of 5-40 mm, and the base concrete layer is also placed on the side surfaces of the soil prism to its lower part; between the prefabricated coating of prestressed concrete slabs and the top layer of the base there is a leveling layer with a thickness of 20 mm to 50 mm from sand reinforced with cement, and a geotextile mesh is laid between the reinforced soil and the bottom layer of the base.

Images