RU2740184C1 - Fibrous-containing mixture for pavement - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to road construction mixtures, particularly to production of modern material for road pavement with improved physical and mechanical properties. Mixture contains a composite binder of the first bitumen of the first row: BND 200/300, BND 130/200, BND 90/130, BND 60/90, BND 40/60 85–95, together with one of the second row bitumen: MG 40/70, MG 70/130, with predominance in the binder bitumen of the first row; polyacrylonitrile fibre; mineral powder; filler in form of sand and regenerated asphalt concrete in their percentage ratio, %: binder - 4–6, water - 3–12, polyacrylonitrile fibre - 0.2–0.4, oleic acid - 0.2–0.6, mineral powder - 4–12, regenerated asphalt concrete - 20–40, sand is the balance.

EFFECT: technical result is improvement of physical and mechanical parameters.

1 cl, 1 tbl

Description

The invention relates to the field of road-building mixtures, in particular, to obtaining a modern material for a road surface with improved physical and mechanical properties.

The use of industrial waste to obtain competitive products is one of the urgent tasks of lean production. In the road construction industry, the recycling of used old roadways by incorporating them into new pavements is becoming more common.

There are various compositions of mixtures for creating asphalt pavements, obtained by various technologies using reclaimed asphalt concrete material, described in foreign and domestic patent sources: in EP patent for invention No. 0182937, US for invention No. 4559128, US for invention No. 8206500, KR for invention No. 101487180, KR for invention No. 101654614, RU for invention No. 2702434.

There is a special group of asphalt concrete mixtures for the use of road surfaces in areas requiring high temperature resistance, in particular for areas with hot climates. The addition of fiber-optic fibers to asphalt concrete mixtures can significantly increase the performance properties of road surfaces. In particular, PAN fibers added to asphalt mixes are characterized by the highest thermal stability. The addition of PAN fiber fibers to asphalt concrete mixes significantly increases the performance properties.

The composition of the asphalt concrete mixture is known (patent RU for invention No. 2465231), which includes: crushed stone, fine aggregate, mineral powder, as well as a bituminous binder and reinforcing fibrous filler, with the following ratio of components, wt%: crushed stone - 30-70, fine aggregate - 10-65, mineral powder - 5-40, bituminous binder - 3-15 (over 100% of mineral material), PAN-fiber - 0.1-0.15 (over 100% of the mass of mineral material) and carbon fiber - 0.01-0.15 (over 100% of the mass of the mineral material). As a carbon fiber, the mixture contains finely cut carbon fibers from 3 to 40 mm in length and with an average diameter of 20-22 microns from continuous carbon fiber.

However, a weak adhesion interaction, as it turned out, at the interface between the fiber and bitumen, due to the absence of chemical bonds between the binder and the filler, does not always lead to the expected increase in the strength characteristics of the asphalt concrete mixture.

The closest analogue to the claimed invention is the composition described in RU patent for invention No. 2713051. The composition of the fiber-containing asphalt concrete mixture includes the following components: crushed stone 20-60%, water 3-12%, mineral powder 4-12%, polyacrylonitrile fiber with a density of 0.17-0.77 tex and a cut length of 6-18 mm 0.07- 0.6%, organic binder 4-12%, sand - the rest. Organic binder is a composite of two types of viscous oil road bitumen, in% of the total amount of binder in the mixture: bitumen of one of the grades: BND 200/300, BND 130/200, BND 90/130, BND 60/90, BND 40/60 - 85-95%, together with one of the brands of bitumen: MG 40/70, MG 70 - 5-15%.

However, this patented asphalt concrete composition does not take into account all the possibilities of improving the physicochemical parameters, as well as environmental and other indicators.

In all the identified patents, the Applicant did not find a single solution, as well as in other sources of information using data on the inclusion of asphalt concrete mixtures along with reinforcing PAN fibers of reclaimed asphalt concrete, an actual and promising material as a filler, in the formulations.

Along with the saving of raw materials due to the exclusion of filling components, which can be dispensed with in the case of reclaimed material, the introduction of reclaimed asphalt concrete into the mixture in the above inventions requires preliminary preparation: if necessary, washing, crushing, dividing into fractions, etc. This can increase the cost of the newly produced asphalt pavement on the other hand. Therefore, the choice of each of the components of the composition being developed and the technology of its introduction into the mixture should also be economically feasible.

The objective of the claimed invention is to improve the strength performance characteristics of the resulting coating: shear resistance, rutting resistance, water resistance, crack resistance and environmental friendliness increase, primarily in the conditions of using the road surface at high temperatures.

The essence of the claimed invention lies in the fact that in a fiber-containing mixture for pavement, including a composite binder of one bitumen of the first row: BND 200/300, BND 130/200, BND 90/130, BND 60/90, BND 40/60 - 85 -95, together with one of the second row bitumen: MG 40/70, MG 70/130, with a predominance of first row bitumen in the binder; polyacrylonitrile fiber; mineral powder; filler with sand, the following components are included in their% ratio:

compound binder 4-6 water 3-12 polyacrylonitrile fiber 0.2-0.4 oleic acid 0.2-0.6 mineral powder 4-12 reclaimed asphalt concrete as part of the aggregate 20-40 sand - the rest.

In addition, a mixture is claimed, in which, along with the above-described characteristics, the percentage of the first and second rows of bitumen included in the composite binder, assembled in pairs, is presented as follows: first row bitumen - 85-95%, second row - 5-15%.

EFFECT: improvement of physical and mechanical parameters is enhanced by addition of fiber to the composition of organomineral material PAN in the optimal - increased amount compared to the closest analogue. The described group of components, led by regenerated asphalt concrete and PAN fiber, as well as the necessary amount of oleic acid introduced into it for the best conditions for the manifestation of the reinforcing properties of PAN fiber, as well as for its effect as a surfactant on regenerated asphalt, provide advantages.

An indispensable, irreplaceable component of the mixture is water, which participates and determines the nature of all processes of structure formation. When the components are mixed with water, kinetic wetting occurs as a bulk layer of water flows under the action of gravity and the working body of the mixer. The wetting and spreading of water over the surface of crushed stone, sand, mineral powder and fiberglass is determined, in addition to energy potentials and crystal-chemical features, by the state of their surface. Roughness, porosity, various types of surface “contamination” create energy barriers, resistance to wetting, especially under dynamic conditions, during mixing. This leads to the manifestation of kinetic wetting hysteresis caused by the resistance acting per unit length of the wetting line. The wetting of components with pronounced hydrophilicity is influenced by the thickness of the water film on their surface.

As a surfactant, fatty acid is oleic acid. A set of several claimed components, their investment in the total composition due to the percentage ratios identified during the approbation process made it possible to obtain higher than that of the closest analogue, the specified parameters as:

- shear stability,

- resistance to rutting,

- crack resistance,

- water resistance.

The use of PAN fiber in the claimed invention as a modern reinforcing additive in an asphalt concrete mixture is due to its use to obtain thermally resistant materials, and is characterized by the fact that its thermal stability makes it possible, even at temperatures of 120-130 ° C, practically not to change its qualities during aging. Compared to other fibers, which are completely destroyed under conditions of combined exposure to sunlight, smoke, soot, water, acids, PAN fibers lose strength by only 15%.

When choosing the amount of PAN fiber in the claimed mixture, a number of concentrations were tested to compare their effect on the physical and mechanical properties of the mixture. As a result, a regularity was established between the amount of PAN fiber and the amount of bitumen in the mixture.

In the course of work on obtaining the optimal claimed composition of the mixture and testing the claimed technical result, the material of the asphalt concrete mixture was prepared, in which the components appear:

- oleic acid complying with GOST 7580-91 produced by OOO PKF Nizhegorodkhimprodukt;

- bitumens of the Saratov Oil Refinery, related to viscous oil road bitumen of grades BND 90/130, BND 60/90, BND 40/60, BND 200/300, BND 130/200, corresponding to the requirements of GOST 22245-90;

- reclaimed crushed asphalt concrete;

- mineral powder, obtained, for example, from a part of the reclaimed asphalt concrete by grinding by any existing modern method or purchased powder of the MP-2 GOST R 52129-2003 brand.

Examples of

In accordance with the claimed invention, an optimal composition was obtained (designated No. 1), in which the percentage of the components was as follows:

oleic acid 0.2%, reclaimed asphalt concrete twenty%, mineral powder 4 %, water 3%, compound binder 4%, PAN fiber with a density of 0.17 tex with a cutting length of 6 mm 0.2%, sand - the rest,

the organic binder consisted of two types of road oil bitumen, in% of the total amount of the binder:

viscous bitumen grade BND 200/300 - 85% and

liquid slow-setting bitumen brand MG 40/70 - 15%.

In accordance with the claimed invention, a composition (designated No. 2) was obtained, in which the percentage of the components was different, but within the declared volume:

oleic acid 0.6%, reclaimed asphalt concrete 40%, mineral powder 12 %, compound binder 6%, PAN fiber with a density of 0.77 tex with a cut length of 18 mm 0.4%, sand - the rest,

binder - composed of two types of viscous oil road bitumen, in% of the total amount of binder in the mixture:

viscous bitumen grade BND 40/60 - 95% and

liquid slow-setting bitumen brand MG 70/130 - 5%.

Table 1 shows the results of testing significant key parameters at elevated temperature (50 ° C) and low temperature (0 ° C), samples from composition No. 1 and No. 2 in comparison with the closest analogue.

Table 1

The composition of the applied asphalt concrete material Compressive strength, MPa, at
temperature Shear resistance of adhesion at shear at
50 ° С, MPa Shear stability by the coefficient of internal friction Crack resistance, MPa Water resistance coefficient
20 ° C 50 ° C Sample composition No. 1 3.8 2.1 0.42 0.77 4.6 0.96 Sample composition No. 2 4,3 2.9 0.50 0.92 5.6 0.99 A sample obtained in accordance with the closest analogue (patent RU2713051) 3.6 1.92 0.40 0.75 4.5 0.95

It can be seen from the above results that samples of compositions No. 1 and No. 2 have higher shear resistance, water resistance, crack resistance and a higher ultimate strength at normal (20 ° C), increased (50 ° C) and low (0 ° C) temperatures. The presented data demonstrate the advantages of the introduction of PAN fiber, a compound binder and oleic acid.

Claims (3)

1. Fiber-containing mixture for paving, including a composite binder from one bitumen of the first row: BND 200/300, BND 130/200, BND 90/130, BND 60/90, BND 40/60 85-95, together with one of the bitumen second row: MG 40/70, MG 70/130, with a predominance of bitumen of the first row in the binder; polyacrylonitrile fiber; mineral powder; filler, including sand, characterized in that it includes the following components in their% ratio: compound binder 4-6 water 3-12 polyacrylonitrile fiber 0.2-0.4 oleic acid 0.2-0.6 mineral powder 4-12 reclaimed asphalt concrete as part of the aggregate 20-40 sand - the rest 2. A mixture according to claim 1, characterized in that the amount of bitumen in the composite binder formed from the pairs of the first and second rows of bitumen is distributed as follows: bitumen of the first row - 85-95%, the second row - 5-15%.