RU2554360C1 - Bulk additive for asphalt-concrete mixture (versions) and asphalt-concrete mixture - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: bulk additive for asphalt-concrete mixture, containing (wt %): thermoplastic polymer 71-90, ethylene copolymer, having at least one of the following functional groups: hydroxyl, carboxyl, carbonyl and epoxy 1-28, cellulose fibre 0.5-20. Bulk additive for asphalt-concrete mixture, characterized by the fact that it is obtained by processing the aseptic cardboard package Tetra Pak and contains (wt %): polyethylene 75-88, ethylene copolymer with methacrylic acid 6-15, cellulose fibre 2-10, granulated aluminium foil 2-20. Asphalt-concrete mixture, containing (wt %): rubble of fractions of 5-40 mm 38-80, sand 5.0-53, mineral powder 3.8-20, bitumen 4.0-7.5, granular additive 0.4-1.0 indicated above.

EFFECT: simplification of technology, increase of strength, increase of resistance to cyclic loads.

6 cl, 4 tbl

Description

The invention relates to road-building materials, namely to bulk additives for asphalt mix and asphalt mix used in the construction of roads and airfield coatings.

To improve the quality indicators of asphalt concrete mixtures, various additives are widely used - modifiers and (or) stabilizers.

Known bulk additive for asphalt mix containing 28.0-38.0 wt.% Bitumen BND 60/90, 31.0-35.0 wt.% Polyamide fiber, 30.0-35.0 wt.% Polymer reinforcing an ingredient containing pipeline waterproofing waste - ArmPEVA, which is a waste of a two-layer shrink tape tape for pipe insulation, consisting of a layer of adhesive active composition of hot-melt adhesive based on a copolymer of ethylene with vinyl acetate and a layer of radiation-crosslinked polyethylene treated with electrons, with a hot-melt applied to it glue, and 1.0-2.0 wt. % of the cationic type surfactant - KADEM-BT, which is a cationic reagent made from plant or animal acids of fractions C ₁₆ -C ₂₀ and polyethylene polyamine (RU 2272795, 2006).

Also in RU 2272795 an asphalt concrete mixture is described containing 93.35-94.65% by weight of the mineral part, 5.0-6.0% by weight of bitumen and 0.35-0.65% by weight of said loose additive.

In the manufacture of an asphalt concrete mixture with a known additive, it is necessary to pre-mix this additive with crushed stone and crushed sand and then add mineral powder and bitumen with additional mixing to obtain a homogeneous mixture, which complicates the technology for manufacturing the asphalt concrete mixture. In addition, asphalt concrete obtained from the known asphalt mixture has a relatively low tensile strength at 50 ° C.

The objective of this group of inventions is to provide a bulk additive for asphalt concrete mix, which allows to simplify the manufacturing technology of asphalt concrete mix, and increase the tensile strength at 50 ° C of asphalt concrete made using such an additive, and increase its resistance to cyclic loads, namely resistance to rutting.

The solution to the problem is a bulk additive for an asphalt mixture containing (wt.%):

 thermoplastic polymer 72-90  an ethylene copolymer having at least one of the following functional groups: hydroxyl, carboxyl, carbonyl and epoxy, or grafted polyethylene maleic anhydride 1-28  cellulose fiber 0.5-20

As a thermoplastic polymer, which may be a product of processing solid waste, it is preferable to use both low and high density polyethylene, polypropylene, polyamide, polyethylene terephthalate or polystyrene.

The solution to the problem is also a bulk additive, characterized in that it

obtained by processing aseptic cardboard packaging Tetra Pak (Tetra Pak) and

contains (wt.%):

 polyethylene 75-88  ethylene methacrylic acid copolymer 6-15  cellulose fiber 2-10  ground aluminum foil 2-20

The solution to the problem is also an asphalt mixture containing (wt.%):

crushed stone fractions 5-40 mm 38-80 sand 5.0-53 mineral powder 3.8-20 bitumen 4-7.5 any of the above bulk additives 0.4-1.0

Thermoplastic polymer increases the strength of asphalt concrete at 50 ° C and resistance to cyclic loads, namely resistance to rutting.

At least one of the functional groups present in the ethylene copolymer, such as a hydroxyl, carboxyl, carbonyl or epoxy group, or a carbonyl group present in grafted maleic anhydride polyethylene binds to bitumen asphaltenes and a thermoplastic polymer, thereby combining the thermoplastic polymer with bitumen. This combination increases the mechanical strength of asphalt concrete and its resistance to cyclic loads. In addition, this combination allows more efficient operation of the thermoplastic polymer in the composition of the asphalt mix, which provides higher strength characteristics of asphalt concrete with a small amount of additive.

An important characteristic of the interaction of bitumen and mineral material is their adhesion. The mineral material for the preparation of the asphalt mixture is characterized by a different content of silica. According to the SiO ₂ content, the rocks are divided into ultrabasic - SiO ₂ in the rock is less than 45%, the main - SiO ₂ content is in the range from 45% to 54%, medium - SiO ₂ content is in the range from 54 to 65% and acidic - SiO content ₂ more than 65%. The adhesion of bitumen with acidic rocks is much weaker than with basic.

The role of ethylene copolymers with the presence of said functional groups or polyethylene grafted with maleic anhydride is to increase the level of adhesion between bitumen and mineral material (gravel) by interaction with said functional groups on the SiO ₂ surface rubble.

Cellulose fiber is used to prevent bitumen from swelling in the asphalt mix.

The bulk additive of the present invention can be obtained using conventional mechanical methods — by mixing the raw materials in an extruder to form granules or by agglomeration to form an agglomerate.

In the second embodiment, the bulk additive of the present invention can be obtained by processing aseptic cardboard packaging Tetra Pak (Tetra Pak) and contain (wt.%):

 polyethylene 75-88  ethylene methacrylic acid copolymer 6-15  cellulose fiber 2-10  ground aluminum foil 2-20

In this case, the disposal of the indicated packaging, the low cost of the bulk additive and the expansion of the raw material base to obtain the additive are additionally ensured.

Table 1 shows examples of granular additives of the present invention.

Table 2 shows the physical and mechanical properties of asphalt concrete obtained using the granular additives of the present invention (samples No. 1-7 of table 1), taken in an amount of 0.5 wt. % by weight of the asphalt mixture, and a comparative example without bulk additives. Asphalt mixtures were made taking into account GOST 31015-2002 (ЩМА-15) and GOST 9128-2009 (Type A) on bitumen oil road BND 60/90 produced by the Moscow Oil Refinery. All the ingredients heated (except for the bulk additive) in accordance with the requirements of GOST 9128-2009 or 31015-2002 were fed into the mixer in a random order, followed by stirring until a homogeneous mixture was obtained for a time sufficient for the polymer components of the bulk additive to become viscous . At the same time, bitumen can be heated to a temperature of 120-190 ° C, mineral ingredients at the outlet of the dryer drum can be heated to 160-250 ° C depending on the set temperature of the asphalt concrete mix produced, and the mixing time is 40-120 seconds.

As follows from table 2, asphalt concrete made using the granular additive of the present invention, has improved physical and mechanical properties. In addition, the presence of ground aluminum foil in the additive does not adversely affect these indicators.

Table 3 shows the physical and mechanical properties of the following asphalt concrete (oil road bitumen BND 60/90 from the Moscow Oil Refinery was used): ЩМА-15 and Type A without additives, with different contents of sample No. 1 of the granular additive of the present invention in the asphalt mixture (sample No. 1 in the form of granules was obtained by processing aseptic cardboard packaging Tetra Pak (Tetra Pak)) and with the well-known loose additive (RU 2272795) in an asphalt mix.

Как следует из таблицы 3, предел прочности при сжатии при 50°C для асфальтобетона с сыпучей добавкой по настоящему изобретению выше, чем для асфальтобетона с сыпучей добавкой по RU 2272795.

As follows from table 3, the compressive strength at 50 ° C for asphalt concrete with a bulk additive of the present invention is higher than for asphalt concrete with a bulk additive according to RU 2272795.

In addition, for specimen No. 1 of the granular additive of the present invention, the adhesion index was determined. The essence of the method is to determine the ability of viscous bitumen to retain on the surface of the mineral material previously coated with it when exposed to water. The purpose of the determination was to assess the ability of the bulk additive (sample No. 1) of the present invention to influence the adhesion rate of bitumen and mineral material. The determination was carried out in accordance with the methodology of GOST 11508-74, but in the boiling mode. The essence of the method is that first the gravel is completely covered with bitumen, then boiled in water, then it is estimated how much of the surface area of the gravel remains covered after exposure to boiling water.

The tests were carried out on samples of gabbro-diorite and gabbro-diabase gravel. The crushed stone was crushed, a fraction from 2 to 5 mm in size was sieved through metal sieves. Pieces with polished surface were separated. The rest was washed with distilled water and dried at 105-110 ° C for 5 hours.

Bitumen grade BND 60/90 produced by the Moscow Oil Refinery and bitumen grade BDUS 70/100 produced by the Kirishi Oil Refinery were used. The adhesion was measured both with bitumen without the indicated bulk additive and with bitumen with such an additive. A bulk additive was added to bitumen as follows:

- bitumen was heated to 180 ° C;

- a granular additive was gradually added to the molten bitumen with constant stirring;

- mixed the composition until the polymer component of the granular additive is completely dissolved.

The results obtained have 4 gradations from worst to best:

- “does not match” means coating with bitumen less than 1/2 of the surface of the mineral material after exposure to water;

- "Control sample No. 3" means the coating of bitumen more than 1/2, but less than 3/4 of the surface of the mineral material after exposure to water;

- "Control sample No. 2" means the coating of bitumen more than 3/4 of the surface coating of the mineral material after exposure to water;

- "Control sample No. 1" means the full coverage of the surface of the mineral material after exposure to water.

The results of determining the adhesion index of the mineral material with bitumen compositions are presented in table 4.

As follows from table 4, the granular additive of the present invention increases the adhesion rate of bitumen with gravel of gabbro-diorite, gabbro-diabase and granite rocks.

Claims (6)

1. Bulk additive for asphalt mix containing (wt.%):
thermoplastic polymer 71-90 an ethylene copolymer having at least one of the following functional groups: hydroxyl, carboxyl, carbonyl and epoxy 1-28 cellulose fiber 0.5-20 2. The bulk additive according to claim 1, characterized in that polyethylene grafted with maleic anhydride is selected as a copolymer of ethylene with a carbonyl group. 3. The bulk additive according to claim 1, characterized in that the thermoplastic polymer is a solid waste processing product. 4. The bulk additive according to claim 1 or 3, characterized in that the polymer from the following group is selected as a thermoplastic polymer: low density polyethylene, high density polyethylene, polypropylene, polyamide, polyethylene terephthalate, polystyrene. 5. Bulk additive for asphalt mix, characterized in that it is obtained by processing aseptic cardboard packaging Tetra Cancer (Tetra Pak) and contains (wt.%):
polyethylene 75-88 ethylene methacrylic acid copolymer 6-15 cellulose fiber 2-10 ground aluminum foil 2-20 6. Asphalt mixture containing (wt.%):
crushed stone fractions 5-40 mm 38-80 sand 5.0-53 mineral powder 3.8-20 bitumen 4.0-7.5 loose additive according to any one of paragraphs. 1-3 or according to claim 4 0.4-1.0