RU2592296C1 - Method of elimination of local depressions on asphalt concrete coating of motor roads - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to road construction, particularly to methods of elimination of local depressions on asphalt concrete coating of motor roads. Method of elimination of local depressions on asphalt concrete coating of motor roads includes cleaning of depression, placing a layer of granulated asphalt concrete mixture, providing plastification of bitumen in it and further layer compaction of asphalt concrete mixture. Road pavement layer is formed by one course or if necessary, layer-by-layer by stacking layer on the bottom of recess or the next sublayer above it of granular asphalt mixture with addition of the particles of combustible substance to it, for example, peat, in amount required for plastification of bitumen and ensure combustion of the particles in it with its or their subsequent compaction as a whole.

EFFECT: technical result is providing the possibility of preparing the asphalt mixture year-round and plastification of its layer directly after laying on the road bed without use of energy-intensive equipment, as well as reducing material consumption and labour intensity.

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Description

The invention relates to the field of road construction, in particular to methods for eliminating local depressions on the asphalt road surface.

It is known that road pavement of roads, as a rule, includes a compacted soil layer, a base layer of road pavement of crushed stone, stone, concrete, etc. and a layer of pavement, in particular of asphalt mixture [1]. The operational performance of roads is largely determined by the type of road surface, the quality of the materials used, and the perfection of the technology of their formation. However, in the process of their operation, defects on the road surface inevitably appear, arising both under the influence of car traffic and under the influence of natural and climatic factors. These primarily include local depressions (cracks, depressions, pits), edge destruction, breaks and other coating defects [1].

Known methods for eliminating local depressions with an asphalt mixture using hot and cold technologies [2], differing in the ways of plasticizing bitumen in it.

When using hot technology, the quality of pavement sealing is high, but this method of eliminating depressions depends on weather conditions and the accuracy of adhering to the technology, including hard temperature conditions. To a lesser extent, this effect is affected when bitumen-containing mixtures and materials based on liquid or liquefied bitumen are used.

When choosing between hot and cold technologies for eliminating defects on asphalt concrete pavements, it should be taken into account that the strength and water resistance of cold asphalt concrete prepared on liquid or liquefied bitumen is 2 ... 3 times lower than hot.

A close analogue of the present invention is a technical solution [3], containing both a method for granulating a hot asphalt mixture and a method for its application. In it, a method for granulating a hot asphalt mixture consists in mixing hot asphalt mixture in water at a water temperature of at least 90 ° C at the beginning of the granulation process and at a water temperature of 30 ° C at the end of the granulation process, while the granular asphalt mixture is further cooled down on air. The very method of using granular asphalt mixes to eliminate defects on asphalt concrete pavements consists in preparing a cold asphalt mix with a light hydrocarbon thinner bitumen, i.e. with a plasticizer of the latter, at least kerosene. In this case, the percentage of bitumen thinner relative to the mass of bitumen in the composition of the asphalt mix with decreasing air temperature is constantly increasing.

The disadvantages of this method, implemented by cold technology, are:

- strength and water resistance obtained after repair of asphalt concrete is 2 ... 3 times lower than that formed by hot technology;

- the preparation of cold asphalt mixes is associated with a high consumption of diluent, i.e. kerosene, which after laying in a defective place evaporates, polluting the environment;

- before laying the cold asphalt mixture in a defective place, heating and priming with bitumen on its surface is required.

The objective of the invention is the provision of plasticization of bitumen granular asphalt mix immediately after laying it on the bottom of the recess.

This is achieved by the fact that the pavement layer is formed in a single layer or, if necessary, layer by layer by laying on the bottom of the recess a layer or another sublayer above it from a granular asphalt mixture with the addition of particles from a combustible substance, such as peat or sawdust, in an amount necessary for plasticizing bitumen in it and ensuring the combustion of particles in it, followed by it or their compaction as a whole.

The use of peat particles of varying degrees of dispersion, i.e. from powders to macrograins, it allows granulation of the asphalt mixture all year round for the future, while avoiding the caking of granules during storage by separating them with a layer of powder from peat.

Ensuring the combustion of peat particles can be carried out in different ways by setting them on fire: using gas burners; impregnated granules with a combustible liquid when added to the asphalt mixture; after spraying with a flammable liquid the laid layer (sublayer) of the road surface.

As a result of peat combustion, the outer layer of bitumen of asphalt concrete granules is liquefied, and the remaining mass on them becomes viscous. In this case, part of unburned peat plays the role of a stabilizing additive [4], which improves the quality of the road surface.

The amount of peat added to the granular asphalt mixture in the form of particles (grains) is established on the basis of their observance of the condition (excluding heat loss) that the combustion energy of peat Q ₁ in it is equal to the heat content of its bitumen Q ₂ located in front of the flash point (t = 240 ° C).

In this case, the combustion energy of peat is determined by the formula [5]:

Q ₁ = m ₁ Η,

where m ₁ is the mass of fully burnt peat, kg;

N = 15 MJ / kg - the calorific value of peat or sawdust.

In turn, the heat content obtained with bitumen can be determined from the dependence [5]: Q ₂ = с m ₂ t,

where c = 1.9 kJ / (kg · K) is the specific heat of bitumen;

m ₂ is the mass of bitumen, kg;

t = 240 ° C is the temperature of bitumen.

Equating Q ₁ = Q ₂ , we obtain the ratio of the mass of peat to the mass of bitumen m ₁ / m ₂ = with t / H = 1.9 · 10 ³ · 240/15 · 10 ⁶ = 1/33.

Consequently, the mass of peat particles relative to the mass of bitumen in the granular asphalt mix will be about 3%, and taking into account heat losses not more than 5 ... 6%.

Clearly, the advantages of the proposed method during its implementation can simply be modeled using available means. So chilled pieces of bitumen to a temperature of minus 5-8 ° C in the refrigerator’s freezer were crushed with a wooden pestle into granules 4 ... 6 mm in size, which were mixed with sawdust soaked in kerosene, and the whole mixture was placed on the bottom of a ceramic bowl with a diameter of 120 mm and then ignited. In the process of burning sawdust, bitumen was not allowed to ignite on the surfaces of granules throughout the entire volume of the layer. After combustion of the sawdust, the viscous-flowing component of bitumen is compacted to a monolith by a water-wetted pestle.

The advantages of this method are:

- the possibility of plasticizing the asphalt mix after laying it on the bottom of the local recess in an autonomous mode;

- there is no need to use means for heating and priming the surfaces of the local recess;

- the ability to produce granular asphalt mix year-round for the future without caking its granules by separating them with a layer of peat powder or sawdust.

- ease of implementation at the workplace in a wide range of air temperatures without the use of expensive devices and materials;

- low material consumption and labor intensity;

INFORMATION SOURCES

1. Silyanov V.V. Transport and operational qualities of roads and city streets: a textbook for students. higher textbook. institutions / V.V. Silyanov, E.R. Domke. - 3rd ed., Erased. - M.: Publishing Center "Academy", 2009. - 352 p.

2. www.OS1.ru/article/rood-equipment/2006-5-A-2006-09-29-18-11-55/.

3. RF patent for the invention No. 2367630, IPC С04В 26/26, Е01С 7/10, A method for granulating an asphalt concrete mixture and a method for using this mixture for repairing asphalt concrete coatings in winter conditions / B.C. Prokopets, O.A. Rychkova, S.F. Filatov. - Publ. 09/20/2009, bull. No. 26.

3. RF patent for the invention No. 2479524 IPC SB04/26. A stabilizing additive for peat-based asphalt mix (options) and a method for producing a structure-forming agent for it. - Publ. 04/20/2013, bull. No. 11.

5. Kuhling X. Handbook of Physics: Trans. with him. - M .: Mir, 1982. - 520 p.

Claims (1)

A method for eliminating local depressions on an asphalt concrete pavement of roads, including cleaning the depressions, laying a layer of granular asphalt concrete mix, providing plasticization of bitumen in it and subsequent compaction of the asphalt mix layer, characterized in that the paving layer is formed in a single layer or, if necessary, layered by laying on the bottom deepening a layer or another sublayer above it from a granular asphalt mixture with the addition of particles from a combustible substance, for example peat meter, in the amount necessary for plasticizing bitumen in it and ensuring the combustion of particles in it, followed by it or their compaction as a whole.