RU2351703C1 - Method for production of cold organic mineral mixture for road pavements - Google Patents

Abstract

FIELD: construction, road construction.

SUBSTANCE: invention is related to production of road construction materials, namely, to methods for production of cold organic mineral mixtures on the basis of mineral fillers and organic binding agents. In method for production of cold organic mineral mixture for road pavements, filler of initial raw materials is mixed with water in mixer, then organic binding agent heated up to 140-160°C in introduced in mixer, and mixing goes on until binding agent is completely dispersed, and uniform mixture is prepared. Process is carried out without heating of both initial raw material filler with temperature of 5-18°C and water. Per 100% of filler 4-11% of water are taken and 3-9% of organic binding agent.

EFFECT: reduction of power and labour inputs in production with increased ecological compatibility.

8 cl, 6 ex

Description

The invention relates to the production of road-building materials, and in particular to methods for preparing cold organic-mineral mixtures based on mineral fillers and organic binders.

Cold mixtures are called those for the preparation of which liquid road bitumen is used and the starting materials are heated to high temperatures. Cold mixtures, unlike hot ones, laid at a temperature of at least 120 ° C, are laid at ambient temperatures of at least 5 ° C without special heating.

A known method of preparing cold asphalt mixtures according to patent RU No. 2190579 for the invention by mixing the mineral part with a liquid bitumen-rubber binder, consisting of bitumen heated to a temperature of 170-190 ° C, 10-15 wt.% Shale oil, rubber solution.

There is also a method of preparing cold asphalt mix [USSR author's certificate No. 707945], which consists in mixing liquid petroleum bitumen grades SG 70/130, MG 70/130, as well as more viscous bitumen BND 200/300 with waste crushing cast slag crushed stone, heated to a temperature of 105-120 ° C, depending on the viscosity of the bitumen used.

There is also a method of preparing sandy asphalt according to RU patent No. 2174498 for an invention, which includes the following operations: processing of products of screening stone crushing of sulfur production in the cold state with oil sludge, heating to 100-110 ° C and mixing with preheated to a temperature of 80-90 ° C bitumen to a homogeneous mass. As an organic binder, MG 70/130 liquid petroleum bitumen is used.

There is also known a method of preparing a cold asphalt mixture [USSR author's certificate No. 1214626] by mixing mineral materials heated to 120-130 ° C with an activating component in the form of a mixture containing 70-75% of the absorption oil regeneration waste and heated to a temperature of 150-160 ° C 25-30% polystyrene, in the amount of 1.5-4.5% of mineral materials with an oil binder. As a binder, use oil liquid bitumen grade MG 130/200 or liquid oil binder.

There is also known a method of preparing a cold asphalt mixture [USSR author's certificate No. 453417], which includes the sequential introduction and mixing at a temperature of 60 ° C of liquid petroleum bitumen, epoxy resin brand ED-5, polyethylene polyamine and filler in the form of a mixture of crushed stone, sand and mineral powder.

There is also a method of preparing cold asphalt mix [USSR author's certificate No. 1458343] by activating sand of an 8-12 wt.% Solution of a polyethylene film in tetrochloromethane in a ratio of 1:10 at a temperature of 60-65 ° C and mixing it with a black binder in the form of oil tar .

There is also a method of preparing a cold asphalt mixture [patent RU No. 2046771 for an invention] by heating mineral materials to a temperature of 110-120 ° C, mixing them with a modifying mixture consisting of the remainder of the production of ionol at the rectification stage — Agidol-80, and then with liquid bitumen grade MG 70/130.

There is also known a method of preparing a cold asphalt mixture [patent RU No. 2186746 for the invention], which includes heating the gravel-sand mixture to 90-160 ° C and sieving into coarse and fine fractions. Thinners - fuel oil, oil tar in an amount of 1.6-3% with a temperature of 60 ° C are mixed with a large fraction of aggregate for 10 seconds, then a viscous oil bitumen BND 90/130 is added, heated to 90-130 ° C, and mixed for 15-20 seconds, there is served fine aggregate and mineral powder, the mixture is stirred for 30 seconds.

The disadvantages of the known methods are as follows. A number of the described methods require special equipment, special safety conditions due to their harmfulness, which makes production more expensive. Another group of methods is based on the use of rare components in the regions that are characteristic only of the residues of certain specific chemical industries. Another and the main disadvantage of the above methods is the need for heating the mixtures of mineral materials involved in the preparation process, which requires additional energy. Heating mixtures to high temperatures is accompanied by environmental damage and the deterioration of working conditions of working personnel

The closest analogue to the claimed invention is a method for preparing a bitumen-mineral mixture [USSR author's certificate No. 883221], which is carried out as follows: metering mineral materials - limestone crushed stone fractions of 5-15 mm, limestone sowing with a particle size of 2.1, limestone mineral powder and load into the mixer. Then water is supplied with a temperature of 20-70 ° C in an amount of 12-14% of mineral materials and mixed for 1 min. Viscous bitumen heated to 160 ° C is introduced into the mixture and mixed for 50 seconds until the bitumen is completely dispersed and a homogeneous asphalt mixture is obtained. This technology is the most environmentally friendly, labor- and energy-saving, since the mineral components are not heated until the start of the mixing process.

However, this method also has disadvantages: the energy consumption associated with the need to heat the water, the delayed formation time and low properties of the coatings obtained from the mixture due to the elevated temperature (20-70 ° C) and an excessive amount of water introduced into the mixture (12-14%) , which is explained by studies conducted subsequently by the authors of the claimed invention.

The objective of the invention is to reduce the energy and labor costs of the method while improving the technological parameters of the mixtures and increasing water saturation, swelling, frost resistance and shear resistance of coatings made from mixtures according to the claimed method.

The essence of the claimed invention lies in the fact that in the method of preparing a cold organic-mineral mixture for road surfaces, in which the filler of the feedstock is mixed with water in the mixer, then the organic binder heated to 140-160 ° C is introduced into the mixer and continued to mix until the binder is completely dispersed and to obtain homogeneity of the mixture, the process is conducted without heating both the components of the filler of the feedstock with a temperature of 5-18 ° C, and water, while the number of incoming components is subject to the ratio:

4-11% water

100% filler 3-9% organic binder

In addition, the claimed method with the above operations, in which as a filler of the feedstock, mineral components are introduced into the mixer: crushed stone, sand, mineral powder.

A method is also claimed with the above operations, in which particles of the old asphalt concrete coating are introduced into the filler of the feedstock in an amount of up to 70% of the total amount of filler.

A method is also described with the above operations, in which cement is introduced into the composition of the feedstock filler in an amount of 1-10% of the total amount of the feedstock filler.

A method is also claimed with the above operations, in which petroleum bitumen is introduced as an organic binder.

A method is also claimed with the above operations, in which shale bitumen is introduced as an organic binder.

A method is also claimed with the above operations, in which an organic binder is introduced as an organic binder, including both oil and shale bitumen.

A method is also claimed with the above operations, in which an organic binder is introduced as an organic binder, including both oil bitumen and coal tar.

The technical result, the achievement of which the creation of the invention is directed, is that in the indicated temperature range and the amount of water included in the mixture, an improvement in the technological parameters of the mixture, indicators of water saturation, swelling, frost resistance and shear resistance of coatings made from mixtures is established.

In addition, the technology for the preparation of materials with dispersed organic binders has significant advantages: energy saving, since there is no need to dry and heat the mineral components; resource saving due to exclusion from the production line of a drying drum, nozzle, furnace, dust collector, screen, the need for their maintenance, reducing the plant’s metal consumption, consumption of mineral powder, etc .; environmental safety, since thanks to the cold and wet preparation of mixtures, the emission of dust, various oxides, carcinogenic hydrocarbons, and others into the atmosphere is excluded

The advantage of the obtained materials with dispersed bitumen over materials on emulsions is that there is no need for the advance production of emulsions on special equipment using scarce, expensive surface-active emulsifiers, often purchased abroad.

The inventive method allows to obtain a wide range of materials with dispersed binders.

Partial or complete replacement of crushed stone in the particular case of use with crushed old asphalt makes it possible to obtain cold regenerated asphalt mixes for the installation of pavements and bases with properties not inferior to materials prepared from traditional raw materials. By analogy, it is possible to prepare and apply cold organic-mineral mixtures from natural oil and bitumen-containing rocks (asphalts, asphalts, kira, etc.)

As a result of replacing a certain amount of mineral powder with cement, a material is obtained that combines the properties of cement and asphalt concrete - cement-asphalt concrete for pavements operating in difficult conditions. With the complete replacement of the mineral powder with cement, cement concrete with additives of organic binders is obtained. The fundamental possibility of producing organomineral mixtures with dispersed binders from incoherent, loose rocks (soils, sand and gravel mixtures, etc.) has been established.

The technology allows the use in dispersion of all known organic binders used in road construction: oil and shale bitumen, resins, coal and other types of tar, etc.

The processes of structure formation in materials with dispersed binders begin at the mixing stage, continue and end in pavement. The mixture is an open type heterogeneous irreversible system, the processes taking place in it occur in the direction of reducing the total excess energy, achieving stable equilibrium. The speed of these processes is determined by the composition, properties, temperatures of the starting materials, weather conditions (sun, wind, air temperature, etc.). The limit of structure formation is the formation of the binary system “bitumen - mineral constituents”.

The production of organic-mineral mixtures with dispersed binders can be carried out by modern machines and equipment. Agitators can be used free and forced action. The latter is preferable, but for soil mixtures mandatory.

The transportation of mixtures, the distribution in layers of pavement and compaction can be carried out by conventional methods.

It is advisable to use organomineral materials with dispersed binders taking into account the compositions and properties in various structural layers of pavement on roads of all technical categories in III-V road-climatic zones.

The inventive method is as follows. The components of the feedstock filler: crushed stone, sand, mineral powder with a temperature of 5-18 ° C, dictated by the low temperatures of the mineral components under natural conditions, for example, in early spring or late autumn, are fed into the mixer without heating and drying. Simultaneously with mineral materials, water is supplied to the mixer with a temperature of 5-18 ° C in an amount of 4-11% by weight of the filler of the feedstock and mixed with mineral components for about 15 seconds. Then, a preheated binder is simultaneously fed into the mixer in an amount of 3-9% by weight of the filler of the feedstock with a temperature of 140-160 ° C, depending on the viscosity of the bitumen used, and stirring is continued, as a rule, for 20-50 seconds until the bitumen is completely dispersed and uniformity is obtained mixtures. In the process of mixing in the volume of the mixture, a direct slowly decaying bitumen emulsion is obtained on solid emulsifiers, the role of which is played by mineral powders commonly used in road construction. The temperature of the finished mixture when exiting the mixer, as a rule, does not exceed 40 ° C. The main indicator of the quality of the mixture is the dispersion of bitumen. The degree of dispersion is determined visually, it is considered satisfactory if, when the mixture is washed out with water, no lumps, threads or clumps of bitumen are observed. To quantify the dispersion of bitumen, a microscopic method is used.

For the preparation of mixtures, crushed stone and gravel from dense rocks, slags, as well as oil and bitumen-containing rocks (asphaltites, gravels) of fractions of 5-10 mm, 10-20 mm, 20-40 mm, or in the form of mixtures of adjacent fractions in the amount of 30-60%; natural or artificial sand in the form of rock crushing waste in an amount of 20-60% of the total filler mass; non-hydrophobic mineral powder with a particle content of less than 0.071 mm of at least 70% in an amount of 4-16% of the total mass of the filler. The grain composition of the mixture is selected based on the conditions for ensuring minimal intergranular voidness.

To prepare mixtures, in some cases, old asphalt (milled granulate, crushed scrap) is introduced as an additive to the filler of the feedstock. Based on the need to introduce a sufficient amount of mineral powder and seeds in the mixture that disperse bitumen, the maximum content of old asphalt should not exceed 70% of the total mass of the filler.

In regions where there is no shortage of oil raw materials, oil bitumen commonly used in road construction is added to the mixture to prepare mixtures as an organic binder. For example, viscous bitumen grades BND 90/130, BND 130/200, BND 200/300 and liquid bitumen grades SG 70/130, SG 130/200.

In regions where there is a field of oil shale and products of their processing with a shortage of oil, it is recommended to use shale bitumen, for example, grades BS 90/130, BS 130/200, BS 200/300, for the preparation of organic-mineral mixtures.

The studies found that a significant increase in the adhesion of organic binders to mineral materials and some improvement in water properties (water saturation and water resistance) of the obtained material can be achieved by simultaneously introducing oil and shale bitumen into the mixture. Oil and shale bitumen in a quantitative ratio of 10-90% of each binder of its total amount with a temperature of 140-160 ° C are simultaneously introduced into the mixer. In the process of mixing, separate independent dispersion occurs with their solid emulsifier - mineral powder. In the volume of the asphalt mixture form a mixed, slowly decaying bitumen emulsion on a solid emulsifier.

It was also established that the simultaneous introduction of oil bitumen and coal tar into the mixture contributes to a certain decrease in the water saturation and swelling of the resulting materials and does not lead to a decrease in their strength. Perhaps the introduction of a binder, completely consisting of coal tar, grades D-1, D-2, D-3, D-4, D-5, D-6

The studies found that accelerating the processes of structure formation and improving the road-technical properties of coatings (increasing strength and water resistance) can be achieved by introducing cement in an amount of 1-10% of the total filler mass.

The inventive method of preparing a cold organic-mineral mixture allows you to arrange coatings at an air temperature of at least + 5 ° C.

Example 1

The method in accordance with the claimed technology was carried out with the following composition of the starting materials:

Limestone crushed stone fractions of 5-10 mm - 55%

Sand - 35% with temperature Mineral powder - 10% 18 ° C Water - 9% Bitumen of oil grade BND 90/130 - 6% with a temperature of 150 ° C

Properties of the resulting organic-mineral mixture:

Bulk weight, g / cm ³ 2.18 Water saturation,% by volume 9.0 The ultimate tensile strength, MPa, at a temperature of 20 ° C 3.2 50 ° C 1.4 Water resistance coefficient 0.98 Water resistance coefficient during long-term water saturation 0.88

Example 2

The method in accordance with the claimed technology was carried out with the following composition of the starting materials:

Old asphalt fraction 5-15 mm - 50%

Granite crushed stone - 35% with temperature Granite sowing - 8% 15 ° C Mineral powder - 7% Water - 7% Oil bitumen BND 90/130 - 3.5% with a temperature of 150 ° C

Properties of the resulting organic-mineral mixture:

Bulk weight, g / cm ³ 2.23 Water saturation,% by volume 7.20 The ultimate tensile strength, MPa, at a temperature of 20 ° C 2,4 50 ° C 0.9 Water resistance coefficient 0.97 Water resistance coefficient during long-term water saturation 0.81

The resulting organomineral mixture and control laboratory samples satisfy the standard requirements for all parameters.

Example 3

The method in accordance with the claimed technology was carried out with the following composition of the starting materials:

Old asphalt fraction 5-15 mm - 50%

Granite sowing - 40% with temperature Mineral powder - 10% 5 ° C Water - 6% The total content of binders - 5% (bitumen slate BSD 90/130 - 60%, oil bitumen BND 90/130 - 40%) with a temperature of 160 ° C

Properties of the resulting organic-mineral mixture:

Bulk weight, g / cm ³ 2.21 Water saturation,% by volume 6.96 The ultimate tensile strength, MPa, at a temperature of 20 ° C 2,4 50 ° C 1.4 Water resistance coefficient 0.99 Water resistance coefficient during long-term water saturation 0.83

The resulting organomineral mixture and control laboratory samples satisfy the standard requirements for all parameters.

Example 4

The method in accordance with the claimed technology was carried out with the following composition of the starting materials:

Old asphalt fraction 5-10 mm - 60%

Sand - 30% with temperature Mineral powder - 10% 5 ° C Water - 6% Bitumen of oil grade BND 90/130 - 5% with a temperature of 150 ° C

Properties of the coating (values for clearings) obtained on the basis of an organic-mineral mixture:

Water saturation,% by volume 7.7 Swelling,% by volume 1.17 Frost coefficient 0.58 Shear resistance, kN 22 · 10 ³

Example 5

The method in accordance with the claimed technology was carried out with the following composition of the starting materials:

Old asphalt fraction 5-10 mm - 60%

Sand - 30% with temperature Mineral powder - 10% 10 ° C Water - 6% Bitumen of oil grade BND 90/130 - 5% with a temperature of 150 ° C

Properties of the coating (values for clearings) obtained on the basis of an organic-mineral mixture:

Water saturation,% by volume 8.2 Swelling,% by volume 1.28 Frost coefficient 0.52 Shear resistance, kN 20 · 10 ³

Example 6

An example is given to compare the proposed method for preparing the mixture with the closest analogue (SU 883221) and demonstrate the advantages of coatings obtained from the mixture. The method in accordance with the closest analogue (SU 883221) was carried out with the following composition of the starting materials:

Old asphalt fraction 5-10 mm - 60%

Sand - 30% with temperature Mineral powder - 10% 20 ° C Water - 13% Bitumen of oil grade BND 90/130 - 5% with a temperature of 150 ° C

Properties of the coating (values for clearings) obtained on the basis of an organic-mineral mixture:

Water saturation,% by volume 14.7 Swelling,% by volume 6.0 Frost coefficient 0.32 Shear resistance, kN 14 · 10 ³

Claims (8)

1. A method of preparing a cold organic-mineral mixture for road surfaces, in which the filler of the feedstock is mixed with water in the mixer, then the organic binder is heated to 140-160 ° C and mixed until the binder is completely dispersed and the mixture is homogeneous, characterized in that that the process is conducted without heating both the components of the filler of the feedstock with a temperature of 5-18 ° C, and water, while the amount of incoming components has a ratio,% to 100% of the filler:
water 4-11 organic binder 3-9 2. The method according to claim 1, characterized in that as a filler of the feedstock, mineral components are introduced into the mixer, comprising crushed stone, sand, mineral powder. 3. The method according to claim 2, characterized in that particles of the old asphalt concrete pavement are introduced into the filler of the feedstock in an amount up to 70% of the total amount of filler. 4. The method according to claim 1, characterized in that the composition of the filler of the feedstock is injected with cement in an amount of 1-10% of the total amount of filler of the feedstock. 5. The method according to claim 1, characterized in that petroleum bitumen is introduced as an organic binder. 6. The method according to claim 1, characterized in that slate bitumen is introduced as an organic binder. 7. The method according to claim 1, characterized in that as an organic binder is introduced composed binder, including both oil and shale bitumen. 8. The method according to claim 1, characterized in that as an organic binder is introduced composed binder, including both petroleum bitumen and coal tar.