RU2713037C1 - Organomineral mixture for road surface - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the field of road construction materials and can be used in the road construction industry to create modern asphalt concrete coatings. Disclosed organomineral mixture contains the following components: crushed stone 20–60 %, mineral powder 4–12 %, water 3–12 %, basalt fiber with density of 54–240 tex and cutting length of 12–18 mm 0.07–0.6 %, organic binder 4–12 %, sand – balance. Organic binder is a composite of two types of petroleum bitumen road: bitumen of one of the viscous bitumen grades: BND 200/300, BND 130/200, BND 90/130, BND 60/90, BND 40/60 in amount of 85–95 % of total amount of binder in mixture and bitumen of one of grades of liquid slowly bituminous bitumen: MG 40/70, MG 70/130 in amount of 5–15 % of total amount of binder in mixture.

EFFECT: obtaining a mixture for producing a strong asphalt-concrete coating with high shear resistance, water resistance, crack resistance and ultimate strength.

1 cl, 2 tbl

Description

 The invention relates to the field of road-building materials and can be used in the road-building industry to create modern asphalt pavements.

 Asphalt mixtures, depending on the viscosity of the bitumen used and the temperature when laying the pavement on the road, are divided into hot and cold. Of interest for the proposed solution are cold mixtures prepared using oil road bitumen and water, laid at a temperature not lower than + 5 ° C, since they are much cheaper than other mixtures and are used in a wide range of climatic and geographical latitudes almost all year round, with the exception of 2 -3 adverse seasonal months depending on the region of use. Cold asphalt mixtures can be transported over long distances without the risk of loss of quality or changes in consumer properties. In warehouses, they can be stored for a long period without loss of quality.

 Important constituent parts of any asphalt mix are the composition of the group of fillers, which usually contains crushed stone, sand, mineral powder: (RU No. 2240333, RU No. 2232841, RU No. 2447035, RU No. 2535325, RU No. 2530812, copyright certificate SU No. 1778100 ) and the composition of the binder group.

Among the groups of binders in the compositions of materials for the manufacture of asphalt concrete coatings are known binders, represented by one type of bitumen, for example, a binder from the above-mentioned patent (RU No. 2232841) and others.

Among the groups of binders in the compositions of materials for the manufacture of asphalt concrete coatings, composite binders are of interest, which include liquid or viscous bitumen with various modifying additives:

RU patent No. 2535325 - with oil sludge;

RU patent No. 2601327 - with petrolatum;

SU patent No. 729158 - with an emulsifier in the form of a mixture of sodium salts and sodium hydroxide;

RU patent No. 2183600 - with cationic reagent "BIEM", hydrochloric acid, calcium chloride, RTEP rubber thermoplastic elastomer, fuse (phosphatide concentrate);

RU patent No. 2240333 - with amine type cationic emulsifier, polymer adhesive additive, hydrochloric acid;

RU patent No. 2243949 - with a BIEM cationic emulsifier, KADEM-VT surface-active additive, calcium chloride, hydrochloric acid, neonol (ethoxylated phenol alcohol).

Such additives are introduced into bitumen to adjust not only its properties, but also the future pavement, namely, expanding the temperature range of the pavement performance, reducing brittleness, and increasing cracking or rutting resistance.

The disadvantages of the above mixtures is the increasing number of components with complex properties and, as a result, the added cost of the mixture.

The role of such a component for the claimed solution as water is not indifferent in cold asphalt mixes, since it affects the quality of wetting of the components. Therefore, all the analogues used in this application are water-containing bitumen-mineral mixtures for road surfaces.

The scope of cold asphalt mixtures is not intended for the highest categories of roads. Of particular interest are water-containing asphalt concrete mixtures for coatings with fibrous fillers, which make it possible to obtain reinforced asphalt concrete with resistance to the formation of plastic deformations, as a result of which the durability of the road surfaces is increased. As a result of this, it is possible to expand the scope of application of these cold mixtures even in the form of a translation of the category of the resulting pavement towards higher quality.

A known mixture (patent RU No. 2530812), consisting of 0.3 wt.% Basalt fiber; 1.4 wt.% Water; 0.3 wt.% Plasticizing additives and the rest is mineral filler, including sand.

Also known is a water-containing organic-mineral mixture (copyright certificate SU No. 1778100) containing basalt fiber in an amount of 6.5-11% by weight of the total mixture, as well as an astringent, water, a filler and an additive of an organic plasticizer.

The closest analogue of the proposed solution is an aqueous mixture (patent RU No. 2447035), which contains a basalt fiber of 0.20-0.55 wt.%; water 2.30-3.70 wt.%; bitumen BND 90/130 3.40-5.50 wt.%; cationic emulsifier "KADEM-VT" 0.40-0.50 wt.%; the stabilizing additive “OXIPAV-A.30 0.20-0.40 wt.% and mineral material - the rest. The structure of the latter includes granite crushed stone, screening crushing, mineral powder, etc.

The disadvantage of the above patents, including the closest analogue, is the multicomponent binder and the resulting difficulty in ensuring their harmonious combination in the overall composition of the asphalt mix. It is worth noting that basalt fiber has not yet received wide practical application in asphalt concrete mixtures in the Russian Federation, despite the current guidelines for the technology of reinforcing asphalt concrete coatings with basalt fiber additives for the construction and repair of roads (Approved by the decree of Rosavtodor No. OS-12-r of 11.01. 2002). The widespread experience in the manufacture of mixtures with additives of basalt fiber in commercially available mixers of asphalt plants in the Russian Federation is also lacking, including for the above reasons.

The objective of the invention is to obtain a cold water-containing mixture for the manufacture of asphalt concrete pavement with increased shear resistance, water resistance, crack resistance and tensile strength without increasing the complexity of the mixture.

The essence of the claimed invention is characterized in that the organomineral mixture for the road surface includes the following components in their ratio,%:

crushed stone 20-60 mineral powder 4-12 water 3-12 organic binder 4-12 54-240 tex basalt fiber and cut length 12-18 mm 0.07-0.6 sand rest,

while an organic binder is a compound of two types of oil bitumen, road, in% of the total amount of binder in the mixture:

one of the brands of viscous bitumen: BND 200/300, BND 130/200, BND 90/130, BND 60/90, BND 40/60 85-95 together with one of the brands of liquid slowly thickening bitumen: MG 40/70, MG 70/130 5-15

The technical result of the claimed invention.

Distinctive features of the proposed mixture with this composition is the use of a binder in the form of a pair of oil road bitumen: one of the grades of viscous bitumen: BND 200/300, BND 130/200, BND 90/130, BND 60/90, BND 40/60 with one of grades of liquid slow-thickening bitumen: MG 40/70, MG 70/130, in combination with the use of water and reinforcing material, represented by basalt fiber with a density of 54-240 tex and a cut length of 12-18 mm. The combination of any of the bitumen pairs identified and compiled by the Applicant presented above with water and basalt fiber of the aforementioned type of density and cutting is not known. The set of components of the inventive water-containing asphalt mixture, among those described in the literature and used in industry, in the claimed concentration ranges has not been previously applied.

It is these differences of the claimed mixture that provide a solution to the problem posed in the invention, and also contribute to energy conservation, environmental safety and economic efficiency.

The subsequent presentation of the material will be presented using tables 1 and 2, where table 1 shows the shear resistance index of the internal friction coefficient in MPa, and table 2 shows the physical and mechanical properties of fiber-containing asphalt concrete with the addition of basalt fiber.

Studies conducted by the Applicant on the selection of optimal quantities of bitumen contained in a binder and compared with existing binder compositions showed the advantages of the inventive binder in a water-containing asphalt mixture. Any of the obtained pairs empirically identified by the Applicant of bitumen grades: BND 200/300, BND 130/200, BND 90/130, BND 60/90, BND 40/60, with one of the brands MG 40/70, MG 70/130, As it turned out, they optimally solve the problem of wetting and the formation of a bitumen film on the surface of mineral elements and fibers in the volume of a fiber-containing water-containing asphalt concrete mixture. As a result, the problem of the formation of lumps in the mixture is eliminated, which was a persistent marriage when using long particles of fiber, on the one hand, and ordinary, unprepared by special processing, poorly combined with other components of the mixture of fibromaterials, for example, without fluffing of the fibers, on the other. According to the results of studies of composite asphalt mixtures made using basalt fiber, it can be concluded that with an increase in the length of the cut of basalt fiber that exceeds the sizes recommended by the Applicant, the quality of the mixture deteriorated. For example, with a cut length of more than 1 mm, lumps were already observed in the mixture, which caused a deterioration in the quality of the mixture. With a reduction in the length of the cut from 12 mm or less, no improvement in properties was manifested. Optimal for ensuring the quality of the mixture was PAN fiber with a density of 54-240 tex with a cut length of 12-18 mm. As a result, the basalt fiber was fully compatible with other components of the mixture and its more uniform and uniform distribution between the mineral components of the mixture with a subsequent increase in the shear resistance of the coating subsequently (table 1).

Table 1

 During the tests of the claimed technical result by examples, a composition of a water-containing asphalt mixture was prepared, in which the following materials were used:

- crushed granite of the Potapovsky quarry of the Rostov region and limestone crushed stone of the Zhigulevsky quarry of the Samara region, fractions from 5 mm to 10 mm, st. 10 mm to 15 mm, st. 15 mm to 20 mm, corresponding to the requirements of GOST 9128-2013, GOST 31015-2002;

- limestone mineral powder of the Ozinsky plant of the Saratov region, corresponding to the requirements of GOST R 52129-2003;

- river sand produced by OJSC “Saratov River Transport Enterprise” that meets the requirements of GOST 8735-88, GOST 8736 - 2014, GOST 9128;

- bitumen of the Saratov refinery, related to oil road bitumen grades BND 90/130, BND 60/90, BND 40/60, BND 200/300, BND 130/200, MG 40/70, MG 70/130, meeting the requirements of GOST 22,245-90;

- basalt fiber manufactured by Izhbazalt LLC with a density of 54-240 tex and a cut length of 12-18 mm, having an average chemical composition (% by weight): SiO ₂ (47.5-55.0); TiO ₂ (1.36-2.0); Al ₂ O ₃ (14.0-20.0); Fe ₂ O ₃ + FeO (5.38-13.5); MnO (0.25-0.5); MgO (3.0-8.5); CaO (7-11.0); Na2O (2.7-7.5); K ₂ O (2.5-7.5); P ₂ O ₅ (not more than 0.5); SO ₃ (not more than 0.5); other breeds (no more than 5);

- water.

The composition of the water-containing asphalt mixture of the components in the example included:

crushed stone - 51%;

mineral powder - 5%;

 viscous bitumen BND 60/90 - 4.95%;

viscous bitumen MG 40/70 - 0.55%;

sand - 32.1%;

water - 6%

basalt fiber - 0.4%.

Table 2 shows the comparative characteristics of the compositions:

- without the addition of fiber and one type of bitumen grade BND 60/90;

- with the addition of basalt fiber with an optimal cutting length of 15 mm and a density of 240 tex and a binder, consisting of a pair of bitumen grades BND 60/90 and MG 40/70 with different viscosities.

table 2

Type of applied asphalt mix Water saturation,% by volume The compressive strength, MPa, at Water resistance Shear resistance of the shear adhesion ^at 50 ° C, MPa Shear resistance by internal friction coefficient Fracture toughness at a tensile strength of at split at ⁰ ° C, MPa temperature 20 ^o C 50 ^about With A mixture of basalt fiber with a pair of selected bitumen 5.8 3,5 2.2 0.99 0.39 0.87 5 The initial mixture without fiber 6.3 2.6 1,6 0.92 0.28 0.67 4,5

Table 2 shows that the performance of asphalt concrete made from cold water-containing fiber-containing mixture of the above composition slightly increases: tensile strength at 20 and 50 ° C by about 36%, shear resistance by internal friction coefficient - by 30%, shear resistance to adhesion at shear - by 40%, water resistance index - by 8%, fracture resistance index - by 11%, compared with asphalt concrete made without fiber.

 For the processing of fiber, we used the FSBEI HE Saratov State Technical University named after VOLGODORTRANS developed at the Volga Educational and Research Center Gagarina Yu.A. ” a prototype installation for the production of composite fiber-containing asphalt mixes, which allows you to prepare fibrous materials (basalt, polyacrylonitrile and other types of fiber) to introduce them into the composition of asphalt mixes with the aim of reinforcing, increasing the physico-mechanical properties and durability of road surfaces. The installation includes a device for fluffing (splitting) of fiber and a device for blowing it into the mixer of an asphalt concrete plant.

Claims (4)

Organomineral mixture for road surface, characterized in that it includes the following components in their ratio,%: crushed stone                                 20-60 mineral powder                        4-12 water                                       3-12 organic binder                   4-12 density basalt fiber 54-240 tex and cut length 12-18 mm 0.07-0.6 sand                              rest, while organic binder is a compound of two types of oil bitumen road, in% of the total amount of binder in the mixture: one of the brands of viscous bitumen: BND 200/300, BND 130/200, BND 90/130, BND 60/90, BND 40/60               85-95 together with one of the brands of liquid slowly thickening bitumen: MG 40/70, MG 70/130 5-15