RU2748791C1 - Modifier of asphalt-concrete mixture and method for its preparation - Google Patents

Abstract

FIELD: road construction.SUBSTANCE: invention relates to road construction, namely to the compositions of modifiers for asphalt-concrete mixture, it can be used in the construction of road surfaces and bridges in all climatic zones. The modifier for asphalt concrete mixture consists of mechanically activated petroleum coke with a dispersion of 10 to 15 mcm in an amount of 70 wt.% and a mixture of petroleum road bitumen with polyethylene oxidized wax in the amount of 30 wt.%, with a mass ratio of wax:bitumen = 1:30, respectively. The method for obtaining modifier of asphalt-concrete mixture is that at step 1, 30 wt.% of a mixture of petroleum road bitumen with polyethylene oxidized wax is prepared, for which the mixture is fed into a heated mixer in the ratio of wax:bitumen = 1:30 and mixed at a temperature of 120-140°C until the composition is completely homogeneous.At step 2, 70 wt.% of the petroleum coke, which is previously mechanically activated to a dispersion of 10-15 mcm, is taken; it is fed in portions into a heated mixer with a mixture of petroleum road bitumen with polyethylene oxidized wax prepared at stage 1. The mixture is brought to complete uniformity of the composition, the resulting modifier for asphalt-concrete mixture is sent to a granulator, where the final product is obtained in the form of granules of the required granulometric composition.EFFECT: reducing water saturation, increasing long-term water resistance, strength, and crack resistance.2 cl, 1 dwg

Description

The invention relates to road construction, namely, to the composition of the asphalt-concrete mixture modifier and the method for its production and can be used in the construction of road and bridge coatings in all climatic zones.

From the investigated prior art, the applicant identified an invention under the patent of the Russian Federation 2120922 "Activated mineral powder for asphalt concrete mixture". The essence is an activated mineral powder for an asphalt concrete mixture, including a mineral material of carbonate rocks, a second fatty tar and an organic additive, characterized in that a soluble wood resin is used as an organic additive in the following ratio of components, wt%:

Mineral material - 97.8 - 98.2

Second fat tar - 0.5 - 1.3

Soluble wood resin - 0.9 - 1.3

The disadvantage of the known activated mineral powder is that as the strength of the asphalt concrete increases, its fragility increases, which reduces the durability of the asphalt concrete at low ambient temperatures and thereby prevents its intended use. The next disadvantage is that the known analogue does not provide the required strength characteristics of asphalt concrete when used in an asphalt concrete mixture when compressed at 50 ° C and has a low water resistance, which prevents its intended use.

From the investigated prior art, the applicant identified an invention under the RF patent 2196750 "Modified asphalt concrete mixture". The essence is an asphalt concrete mixture, including sand, mineral powder, polymer structuring additive and petroleum bitumen, characterized in that it contains viscous petroleum bitumen, as a polymer structuring additive it contains rubber thermoplastic elastomer and additionally a surfactant, plasticizing additive - tall oil pitch and screening of crushed stone crushing fractions 0-5 mm with the following ratio of components, wt. %:

Sand - 16.0 - 20.0

Mineral powder - 10.0 - 15.0

Rubber thermoplastic elastomer - 0.5 - 1.0

Oil viscous bitumen - 5.0 - 6.5

Tall pitch - 0.3 - 0.5

Screening of crushed stone crushing fraction 0-5 mm - 57.0 - 68.2

The disadvantage of the known technical solution is the relatively low strength index of asphalt concrete mixtures with a structuring additive in the form of rubber thermoplastic elastomer and tall oil pitch at 50 ° C (1.31-1.65 MPa), which characterizes the thermal stability and shear stability of the mixtures, which is especially important for the southern regions of the country. Also, the disadvantage is the lack of technological preparation of mixtures due to the need to pre-modify the bitumen with tallow pitch.

From the investigated prior art, the applicant identified an invention under the patent of the Russian Federation 2377262 "Modifying composition for asphalt concrete mixtures and a method for producing a modified asphalt concrete mixture", The essence in relation to the composition is a modifying composition for asphalt concrete mixtures, including crushed rubber vulcanizate, characterized in that as a crushed rubber The vulcanizate composition contains an active rubber powder with a particle size of no more than 0.8 mm and a specific geometric surface of no less than 5000 m ² / g, obtained by thermomechanical grinding of a rubber vulcanizate in the presence of an anti-agglomerator selected from the group of paraffin, ozokerite and halogen-containing alcohols-telomers in an amount of 0.1-2.0% by weight of the rubber vulcanizate, while the composition additionally contains a metasilicate of a needle structure, a gelation initiator selected from the group of 4-nitro-N-methylaniline, N-methyl-N, 4-dinitrosoaniline, N- (2-methyl-2-nitrope ropyl) -4-nitrosoaniline, N-nitrosodiphenylamine, and at least one structuring agent with an increased induction structuring period of at least 30 minutes at a temperature of 160 ° C, selected from the group of oligomeric epoxy ester resin, epoxy-diane resin, polycondensation resin, which promotes the formation of branched or network structures, with the following ratio of components, wt%:

active rubber powder - 65 - 90

acicular metasilicate - 4.0 - 25.0

gelation initiator - 1.0 - 4.5

structuring agent or structuring agents - 1.7 - 6.0

The essence in relation to the method is a method for producing a modified asphalt concrete mixture, including mixing crushed stone, sand, mineral powder at an elevated temperature and introducing bitumen and a modifying composition, characterized in that first, at a temperature of 140-150 ° C, the components of the mineral component of the asphalt concrete mixture are mixed: crushed stone , sand and mineral powder, and then bitumen, heated to a temperature of 140-150 ° C, is introduced, and simultaneously with the introduction of bitumen or immediately after its introduction, a modifying composition is introduced in an amount of 0.32-3.5% of the mass of the mineral component of the asphalt concrete mixture and at a temperature of 150-180 ° C, while a composition containing the following components is used as a modifying composition:

A) active rubber powder with a particle size of not more than 0.8 mm and a specific geometric surface of not less than 5000 cm2 / g, obtained by thermomechanical grinding of rubber vulcanizate in the presence of an anti-agglomerator selected from the group of paraffin, ozokerite and halogen-containing alcohols-telomers, in the amount of 0.1-2.0% by weight of rubber vulcanizate,

B) metasilicate of acicular structure,

B) a gel initiator selected from the group 4-nitro-N-methylaniline, N-methyl-N, 4-dinitrosoaniline, N- (2-methyl-2-nitropropyl) -4-nitrosoaniline, N-nitrosodiphenylamine,

D) at least one structuring agent with an increased induction structuring period of at least 30 minutes at a temperature of 160 ° C, selected from the group of oligomeric epoxy resin, epoxy-diane resin, polycondensation resin, which promotes the formation of branched or network structures, in the following ratio of components , wt%:

active rubber powder 65-90 acicular metasilicate 4.0-25.0 gelling initiator 1.0-4.5 structuring agent or structuring agents 1.7-6.0

The disadvantages of the known technical solution include a complex technological process for obtaining a composition and expensive modifying additives.

The purpose and technical result of the claimed technical solution is the development of a modifier for asphalt concrete mixtures and a method for its production, including (modifier) mechanically activated petroleum coke to a fineness of 10 to 15 microns and a mixture of petroleum bitumen and a polymer additive, in the form of polyethylene oxidized wax, providing (modifier) with its use improves the complex of physical and mechanical characteristics of the roadway:

- decrease in water saturation,

- increasing long-term water resistance,

- an increase in the ultimate strength in compression at a temperature of 50 ° C,

- decrease in brittleness, increase in crack resistance at 0 ° С,

The essence of the claimed technical solution is a modifier for an asphalt concrete mixture, consisting of mechanically activated petroleum coke with a dispersion of 10 to 15 microns in an amount of 70% wt., And a mixture of petroleum road bitumen with polyethylene oxidized wax, in an amount of 30% wt., With a mass ratio of wax : bitumen = 1:30 respectively. The method of obtaining the modifier of the asphalt concrete mixture according to claim 1, which consists in the fact that in step 1 prepare 30% wt. mixtures of oil road bitumen with polyethylene oxidized wax, for which the mixture is fed into a heated mixer in the ratio wax: bitumen = 1:30 and stirred at a temperature of 120-140 ° C until the composition is completely homogeneous; at stage 2 take 70% wt. pre-mechanically activated to a fineness of 10-15 microns of petroleum coke, it is fed in portions into a heated mixer with a mixture of petroleum road bitumen with polyethylene oxidized wax prepared at stage 1, the mixture is brought to complete homogeneity of the composition, the resulting modifier of the asphalt concrete mixture is sent to the granulator, where the final product is obtained in the form of granules of the required granulometric composition.

At the same time, the applicant explains that, although in accordance with the claims, the mass ratio of wax and bitumen = 1:30, respectively, going beyond the stated limits is also workable, however, when the ratio of wax and bitumen is less than 1:30, respectively, a deterioration in the quality of the modifier is observed , due to increased stickiness in obtaining commercial samples of granules, and the ratio of wax: bitumen is more than 1:30, respectively, leads to a number of technical difficulties in the granulation process, as well as to an increase in the cost of the final product.

The claimed technical solution is illustrated in Fig, which shows the Table of physical and mechanical properties of the asphalt concrete mixture using the claimed modifier obtained by the claimed method.

The stated goal and the claimed technical result is achieved through the development of an asphalt concrete mixture modifier and a method for its production, which differs from analogs in that mechanically activated petroleum coke and a binder additive are used in the modifier.

The following components can be used to prepare an asphalt concrete modifier:

- mechanically activated petroleum coke with a dispersion in the range from 10 to 15 microns. At the same time, the applicant explains that the fineness values from 10 to 15 microns are not the fineness values of different samples (range of values), but characterize the particle size distribution of each sample (that is, each sample consists of particles up to 10 to 15 microns in size), therefore, the applicant is not given examples of the implementation of the claimed method with different values of dispersion;

- petroleum bitumen, corresponding in their performance to bitumen for road, construction, insulation, roofing and other purposes;

- polyethylene oxidized wax is a product obtained by oxidation of homopolymer polyethylene waxes. The affinity of the structures of bitumen and wax is due to the presence of carboxyl and hydroxyl groups in the composition of the polymer unit. The identity of the structure ensures the maximum compatibility of these structures at the molecular level with the formation of a single polymer matrix, which leads to a radical change in the qualitative characteristics of the bitumen binder and asphalt concrete mixture as a whole. The following synthetic rubbers can be used as a polymer component: SEV (copolymer of ethylene and vinyl acetate), obtained by joint polymerization of ethylene and vinyl acetate at high pressure; butyl rubbers; SBS (styrene-butadiene-styrene thermoplastic elastomer, DST (divinyl styrene thermoplastic elastomer), APP (atactic polypropylene, IPP (isotactic polypropylene), low molecular weight polyethylene.

Obtaining an asphalt concrete mixture modifier includes the following steps according to the claimed method:

Stage 1. Getting a binder in the form of a mixture of oil road bitumen (hereinafter referred to as bitumen) and polyethylene oxidized wax (hereinafter referred to as wax) in a heated mixer.

Stage 2. Batch feeding into the mixer from the storage bin of a given amount of mechanically activated petroleum coke (hereinafter referred to as coke) with vigorous stirring. The mixture is brought to complete homogeneity of the composition.

Stage 3. Directing the obtained modifier to the granulator in order to obtain the final product in the form of granules.

The following are specific examples of the implementation of the claimed technical solution.

The applicant has obtained the claimed modifier of the asphalt mixture with different ratios of coke: binder, different ratios of wax: bitumen in the binder and different mixing temperatures in order to select the optimal ratios and optimum temperature to achieve the claimed technical result - see Examples 1-6.

Example 1. Obtaining a modifier of an asphalt concrete mixture with ratios of coke: binder = 70:30, and wax: bitumen = 1:30, respectively, at a temperature of 120 ° C.

In Stage 1, 30% of the binder is obtained in the form of a mixture of petroleum road bitumen and polyethylene oxidized wax in the ratio wax: bitumen = 1:30.

To prepare, for example, 1 kg of an asphalt concrete mixture modifier, 0.30 kg (300 g) of a binder is prepared, from which, for example, 9.67 g of wax and 290.32 g of bitumen are taken (in the ratio wax: bitumen = 1:30) ... Mixing is carried out, for example, in a heated mixer, at a temperature of, for example, 120 ° C, until the composition is completely homogeneous.

The applicant explains that at temperatures below 120 ° C, bitumen is not plastic and does not undergo mixing.

Stage 2 takes 70% wt. pre-mechanically activated to a fineness of 10-15 microns of petroleum coke, for example, 0.70 kg per 1 kg of modifier of asphalt concrete mixture. The petroleum coke is fed in portions from the storage hopper into a heated mixer with a binder with vigorous stirring at a temperature of, for example, 120 ° C. The mixture is brought to complete homogeneity of the composition. In this case, the ratio of coke: binder = 70: 30 is obtained.

Receive the claimed modifier of the asphalt mixture (see table in Fig).

At Stage 3, the resulting modifier of the asphalt concrete mixture is sent to a granulator, where the final product is obtained in the form of granules of the required granulometric composition.

Example 2. Obtaining a modifier of an asphalt concrete mixture with ratios of coke: binder = 70:30, and wax: bitumen = 1:30, respectively, at a temperature of 140 ° C.

The claimed modifier is obtained according to Example 1, while mixing petroleum road bitumen and polyethylene oxidized wax and then mixing petroleum coke with a binder is carried out at a temperature of, for example, 140 ° C (see Table in Fig).

The applicant explains that at temperatures above 140 ° C, bitumen cracking occurs (cracking is a reaction of the decomposition of the carbon skeleton of large molecules upon heating).

Receive the declared modifier of the asphalt mixture.

Example 3. Obtaining a modifier of an asphalt concrete mixture with ratios of coke: binder = 70:30, and wax: bitumen = 1:30, respectively, at a temperature of 130 ° C.

Carry out the receipt of the claimed modifier according to Example 1, while mixing petroleum road bitumen and polyethylene oxidized wax and then mixing petroleum coke with a binder is carried out at a temperature of, for example, 130 ° C.

Receive the claimed modifier of the asphalt mixture (see table in Fig).

Example 4. Obtaining a modifier of an asphalt concrete mixture with ratios of coke: binder = 65:35, and wax: bitumen = 1:27, respectively

An asphalt concrete modifier is prepared according to Example 3, whereby the ratio (wt%) of coke: binder = 65:35 is taken. A binder mixture is prepared from petroleum road bitumen and polyethylene oxidized wax in the ratio wax: bitumen = 1:27 (see Table in Fig).

Example 5. Obtaining a modifier of an asphalt mixture with a ratio of coke: binder = 70:30 and wax: bitumen = 1:25, respectively.

An asphalt concrete modifier is prepared according to Example 3, whereby the ratio (wt%) of coke: binder = 70:30 is taken. A binder mixture is prepared from petroleum road bitumen and polyethylene oxidized wax in the ratio wax: bitumen = 1:25 (see Table in Fig).

Example 6. Obtaining a modifier of an asphalt mixture with a ratio of coke: binder = 65:35, respectively, and wax: bitumen = 1:25, respectively.

An asphalt concrete modifier is prepared according to Example 3, with the ratio (wt%) coke: binder = 65:35, respectively. A binder mixture is prepared from petroleum road bitumen and polyethylene oxidized wax in the ratio wax: bitumen = 1:25 (see Table in Fig).

The asphalt-concrete mixture with the declared modifier was tested in accordance with GOST 9128-2013 “Asphalt-concrete, polymer-asphalt-concrete, asphalt-concrete, polymer-asphalt-concrete mixtures for highways and airfields. Technical conditions "in the accredited testing laboratory of the road organization. The results of the physical and mechanical parameters are presented in the Table in FIG.

As can be seen from the Table in Fig., All indicators of the asphalt concrete mixture with the claimed modifier meet the requirements of GOST 9128-2013. At the same time, the asphalt concrete mixture with the modifier according to Examples 1 - 3 showed better physical and mechanical properties in comparison with the asphalt concrete mixture with the modifier according to Examples 4 - 6.

Based on the above, the applicant included in the claims a composition and a method for producing a modifier according to Examples 1 to 3, namely, the ratio of coke: binder = 70:30, ratio of wax: bitumen = 1:30, mixing temperature 120-140 ° C.

Based on the above experimental data, it can be concluded that the applicant has achieved the goals and the claimed technical result, namely, a modifier of asphalt concrete mixtures and a method for its production based on mechanically activated petroleum coke and a mixture of petroleum road bitumen with polyethylene oxidized wax have been developed, which with a ratio of coke: binder = 70:30 and wax: bitumen in binder = 1:30, respectively, it provides an improvement in the physical and mechanical characteristics of the final asphalt concrete pavement.

The obtained indicators characterize the increase in the main characteristics of the asphalt concrete mixture when using coke powder in comparison with the analogue.

As can be seen from the Table, the use of the claimed modifier obtained according to the claimed method in the preparation of the asphalt concrete mixture provided, in comparison with the analogue according to the RF patent No. 2120922, an improvement in such characteristics as:

- decrease in water saturation from 2.74 to 1.5;

- increasing the water resistance of the asphalt concrete mixture from 0.93 to 0.97 if the GOST requirement is not less than 0.85;

- an increase in the ultimate strength of asphalt concrete under compression at 50 ° C from 1.15 to 1.25 when the GOST requirement is not less than 1.0;

- increase in crack resistance at 0 ° C from 3.8 to 4.5.

All indicators of the asphalt concrete mixture using the claimed modifier meet the requirements of GOST 9128-2013 * "Mixes asphalt concrete, polymer asphalt concrete, asphalt concrete, polymer asphalt concrete for highways and airfields."

The claimed technical solution meets the criterion of "novelty" for inventions, since when determining the level of technology, no technical solution has been identified that has features that are identical (that is, coincide in the function they perform and the form of implementation of these features) of the set of features listed in the claims , including the description of the purpose.

The claimed technical solution meets the inventive step criterion for inventions, since no technical solutions have been identified that have features that coincide with the distinctive features of the claimed invention, and the influence of the distinctive features on the specified technical result has not been established.

The claimed technical solution meets the criterion of "industrial applicability" for inventions, since it can be manufactured using known materials, components, standard technical devices and equipment.

Claims (2)

1. Modifier for asphalt concrete mixture, consisting of mechanically activated petroleum coke with a dispersion of 10 to 15 microns in the amount of 70 wt. % and a mixture of petroleum road bitumen with polyethylene oxidized wax in the amount of 30 wt. % with a mass ratio of wax: bitumen = 1:30, respectively. 2. The method of obtaining the modifier of the asphalt mixture according to claim 1, which consists in the fact that in step 1 prepare 30 wt. % of a mixture of oil road bitumen with polyethylene oxidized wax, for which the mixture is fed into a heated mixer in the ratio of wax: bitumen = 1:30 and mixed at a temperature of 120-140 ° C until complete homogeneity of the composition, at stage 2 take 70 wt. % of pre-mechanically activated to a fineness of 10-15 microns of petroleum coke is fed in portions into a heated mixer with a mixture of petroleum road bitumen with polyethylene oxidized wax prepared at stage 1, the mixture is brought to complete homogeneity of the composition, the resulting modifier of the asphalt concrete mixture is sent to the granulator, where the final product is obtained in the form of granules of the required granulometric composition.

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