RU2799927C1 - Asphalt concrete - Google Patents

Abstract

FIELD: road building materials.

SUBSTANCE: invention relates to the composition of mixtures for the manufacture of asphalt concrete and can be used in the construction of roads, bridges, airfields. Asphalt concrete comprises components in the following ratio, wt.%: natural sand 11-14, crushed stone 45-48, sand from crushing fines 35-39, mineral powder 4-8, bitumen 4.8-5.5 in excess of 100 wt.% mineral parts crushed to a particle size of 0.5 to 35 mm low pressure polyethylene 2-3 over 100 wt.% bitumen, engine oil from 0.1 to 5% by weight of low-pressure polyethylene.

EFFECT: expanding the range of materials while reducing the man-made burden on the environment from waste such as containers made of low-pressure polyethylene comprising residues of motor oils.

1 cl, 1 tbl

Description

The invention relates to road building materials, in particular to hot fine-grained asphalt concrete mixtures, and can be used in the construction of roads, bridges, airfields.

Known asphalt mixture containing bitumen 5.8 - 7.1%, galvanic production waste 6.0 - 12.3%, neutralized pickling sludge 3.5 - 6.4%, crushed stone 32.0 - 48.0%, sand the rest (RF patent No. 2074277, publication date 27.02.1997).

A disadvantage of the known asphalt concrete mixture is low strength at 20°C (compressive strength is 2.0-2.1 MPa) and low water resistance (water resistance coefficient is 0.71-0.80).

Known asphalt mixture, consisting of a bituminous binder with an activating additive in the form of amines, waste sand-gravel mixture, sand-gravel mixture and dolomite screenings. The composition of the mixture waste sand-gravel mixture 43.5%, sand-gravel mixture 33.5% dolomite screenings 13.7%, serobitumen (sulfur, bitumen in a ratio of 1: 1, aniline (pure) is used as a catalyst in an amount of 1.0 g (2% with respect to sulfur) 13-9.3% (RF patent No. 2452748 C1, publication date 10 .06.2012).

The disadvantage of the known asphalt concrete mixture obtained on the basis of a sulfur-bitumen binder is low water resistance (water resistance coefficient is 0.9), low strength at 50°C (tensile strength - 1.25 MPa) and high strength at 0°C (tensile strength - 11.5 MPa), which characterizes the low frost resistance of the mixture.

The closest in technical essence to the proposed one is asphalt concrete containing, wt %: natural sand 11-14, crushed stone 45-48, sand from crushing screenings 35-39, drill cuttings 4-8 as a mineral powder, bitumen 5-5.3 in excess of 100 wt % of the mineral part (RF patent No. 2755172 dated 13.09.2021). This composition is taken as a prototype.

Signs of the prototype, coinciding with the essential features of the claimed invention, are natural sand 11-14 wt.%, crushed stone 45-48 wt.%, sand from crushing screenings 35-39 wt.%, mineral powder 4-8 wt.%, bitumen.

The disadvantage of the known asphalt, taken as a prototype, is the low tensile strength, low water resistance, heat resistance.

The task to be solved by the claimed invention is to expand the arsenal of road building materials by obtaining asphalt concrete using crushed low-pressure polyethylene waste and motor oil, used as a binder and structure-regulating material, with performance characteristics and physical and mechanical properties corresponding to regulatory documents: density and strength of the material, porosity of the mineral composition, water resistance and water saturation.

The task was solved due to the fact that the known asphalt concrete containing crushed stone, natural sand, sand from crushing screenings, mineral powder and bitumen, according to the invention, as a binder and structure-regulating material, it additionally contains low-pressure polyethylene crushed to a particle size of 0.5 to 35 mm, contaminated with motor oils in the following ratio of ingredients, wt. %:

Distinctive features of the proposed invention from the claimed prototype are: the use as a binder bitumen in an amount of 4.8-5.5% over 100 wt.% of the mineral part and crushed to a particle size of 0.5 to 35 mm low-pressure polyethylene waste in an amount of 2-3 over 100 wt.% bitumen containing motor oil in an amount of 0.1 to 5% by weight of low-pressure polyethylene.

The introduction of pre-shredded polyethylene waste in the amount of 2-3 over 100 wt.% of bitumen into the composition of the asphalt concrete mixture, containing engine oil residues in the amount of 0.1 - 5% by weight of low-pressure polyethylene provides an increase in the stability of the mineral backbone of asphalt concrete to external shear loads. Motor oil accelerates the process of uniform distribution of crushed low-density polyethylene waste in the asphalt mix during mixing.

The content of engine oil in an amount of more than 5% by weight of polyethylene is impractical, because this will change the initial viscosity of the bitumen and reduce the strength characteristics of the asphalt concrete.

Distinctive features, together with the known ones, make it possible to reduce the cost of asphalt concrete, while ensuring that asphalt concrete meets the requirements of regulatory documents for operational characteristics and physical and mechanical properties. In addition, this will reduce the technogenic burden on the environment, and the arsenal of road construction materials will be expanded.

For the preparation of asphalt concrete, the following component composition is used:

1. Natural sand, fraction from 0 to 5 mm in accordance with GOST 8735-2014 “Sand for construction work. Test Methods".

2. Crushed stone, fraction from 5 to 20 mm in accordance with GOST 8267-93 “Crushed stone and gravel from dense rocks for construction work. Specifications".

3. Sand from crushing screenings, fraction from 0 to 5 mm in accordance with GOST 8735-2014 “Sand for construction work. Test Methods".

4. Low-pressure polyethylene contaminated with engine oils (content from 0.1 to 5%, individual particle size is not more than 35 mm.

5. Bitumen 90/130 (over 100% MCh), in accordance with GOST 22245-90 “Road oil bitumen. Specifications". Depth of needle penetration 0.1 mm at 25°C - 90.

The use of polyethylene waste in the composition of asphalt concrete does not change the technological scheme of its production. The technological process of obtaining an asphalt concrete mixture with the addition of polyethylene waste is as follows:

Pre-shredded low-pressure polyethylene waste is mixed with mineral components (crushed stone, natural sand, sand from crushing screenings). Then bitumen is introduced into the mixture, heated to a temperature of 165-175°C. After mixing all the components and bringing the temperature of the mixture to the required one, depending on the type of asphalt concrete produced, the finished mixture is released. The technology allows the use of standard equipment used in mass-produced asphalt plants.

The technical result is confirmed by tests for compliance with the requirements of GOST 9128-2013 “Asphalt concrete, polymer asphalt concrete, asphalt concrete, polymer asphalt concrete mixtures for highways and airfields. Specifications”, for which asphalt concrete mixtures were used in the following ratio of components, wt. %:

Mix 1 - natural sand 11, crushed stone 47, sand from crushing screenings 38, mineral powder 4, bitumen BND 90/130 4.8 (over 100 wt.% of the mineral part), low-pressure polyethylene 2 (over 100 wt.% bitumen) with an engine oil content of 0.1%.

Mix 2 - natural sand 11, crushed stone 47, sand from crushing screenings 38, mineral powder 4, bitumen BND 90/130 5.5 (over 100 wt.% of the mineral part), low-pressure polyethylene 3 (over 100 wt.% bitumen) with a motor oil content of 1%.

Mix 3 - natural sand 14, crushed stone 45, sand from crushing screenings 35, mineral powder 6, bitumen BND 90/130 5.0 (over 100 wt.% of the mineral part), low-pressure polyethylene 2.5 (over 100 wt.% bitumen) with an engine oil content of 2%.

Mix 4 - natural sand 11, crushed stone 45, sand from crushing screenings 39, mineral powder 5, bitumen BND 90/130 5.5 (over 100 wt.% of the mineral part), low-pressure polyethylene 3 (over 100 wt.% bitumen) with an engine oil content of 4%.

Mix 5 - natural sand 13, crushed stone 48, sand from crushing screenings 35, mineral powder 4, bitumen BND 90/130 5.3 (over 100 wt.% of the mineral part), low-pressure polyethylene 3 (over 100 wt.% bitumen) with a motor oil content of 5%.

Additionally, an asphalt concrete mixture (initial) containing a traditional bituminous binder was prepared to compare the results of physical and mechanical parameters in the following ratio of components, wt. %: natural sand 12, crushed stone 46, crushing screenings 38, mineral powder 4, bitumen BND 90/130 (over 100% of the mineral part) 5.3.

The compositions of the mixtures and the results of their tests are given in the table:

INDICATORS Requirements GOST 9128-2013 Indicators of control samples Blend 1 Blend 2 Blend 3 Blend 4 Blend 5 Compressive strength, MPa - at 20°С, at least 2.5 4.78 5.25 5.32 5.27 5.34 5.75 - at 50°С, at least 1.2 1.61 1.45 1.40 1.46 1.41 1.35 - at 0°С, no more than 11.0 9.59 9.45 9.25 9.27 9.18 9.05 Shear resistance according to: - coefficient of internal friction, not less than 0.81 0.89 0.90 0.91 0.93 0.91 0.90 - shear adhesion at a temperature of 50°C, MPa, not less than 0.35 0.51 0.53 0.58 0.61 0.60 0.63 Average density, g / cm ³ - 2.41 2.41 2.41 2.40 2.40 2.39 Water resistance, not less 0.85 0.89 0.89 0.90 0.90 0.91 0.91 Water saturation, % 1.5-4.0 1.93 1.80 1.74 1.72 1.70 1.64 Porosity of the mineral part, % 14-19 15.8 15.7 15.6 15.5 15.4 15.4 Residual porosity, % 2.5-5.0 4.05 3.90 3.80 3.85 3.75 3.15

Thus, a hot fine-grained asphalt concrete mix of type B II grade was created with the addition of pre-crushed low-pressure polyethylene waste containing motor oil residues, which has the required strength characteristics, which made it possible to expand the range of materials used in the road construction industry, reduce the cost of asphalt concrete, and also reduce the technogenic load on the environment.

Claims (2)

Asphalt concrete containing natural sand, crushed stone, sand from crushed screenings, mineral powder, bitumen and low-pressure polyethylene crushed to a particle size of 0.5 to 35 mm, contaminated with motor oils, in the following ratio of ingredients, wt.%: