RU2777821C1 - Granulated modifier for asphalt concrete - Google Patents

Abstract

FIELD: construction production.

SUBSTANCE: invention relates to the field of construction production in the road industry and can be used in the manufacture of asphalt concrete, including the use of nanotechnology. The granular modifying additive includes a modifying mixture and a binder. Wherein the modifying mixture consists of single-walled carbon nanotubes in the amount of 0.01-15 wt.%, multi-walled carbon nanotubes in the amount of 0.01-15 wt.%, graphene in the amount of 0.01-15 wt.%, carbon nanofibers in the amount of 0 01-15 wt.% and mineral powder - the rest, and a low-paraffin bituminous binder is used as a binder, in the following ratio, wt.%: modifying mixture 50 and binder 50. In this case, the obtained granules are dusted with cement or mineral powder, where the mass cement or mineral powder is not more than 2.5% by weight of the granules.

EFFECT: reducing the time to obtain modified asphalt concrete, as well as the convenience of transporting the modifying additive.

1 cl, 6 ex

Description

The invention relates to the field of construction production in the road industry and can be used in the manufacture of asphalt concrete, including the use of nanotechnology.

The road surface is expensive and difficult to build and maintain engineering structures. The selection of the optimal bituminous binder, together with the granulometric composition of crushed stone, based on the operational conditions of the final roadway, remains the top priority at present.

Bituminous binders, even selected in accordance with accepted state standards, cannot always provide the required turnaround time for asphalt concrete mixtures. It is the insufficient quality of bituminous mixtures that is the main reason for the low durability of asphalt concrete (brittleness in the temperature range below -20℃, combined with strong softening in the range above 50℃).

To meet the real requirements of climatic environmental conditions and the characteristics of road traffic, it is necessary to use various additives and modifiers in the composition of bituminous binders. Often, polymer additives based on styrene-butadiene-styrene are used as such modifiers.

The closest in technical essence is the method of introducing single-walled and/or double-walled and/or multi-walled carbon nanotubes into the composition of adhesive additives for asphalt pavement and the use of single-walled and/or double-walled and/or multi-walled carbon nanotubes in the composition of adhesive additives (patent RU 2675515, Published: December 19, 2018 Bulletin No. 35). The method consists in the introduction of single-walled and/or double-walled and/or multi-walled carbon nanotubes into the composition of adhesive additives for asphalt pavement by mixing in grinding and roller mills. The disadvantage of this technical solution is the multi-stage and high power consumption.

The claimed invention is aimed at solving the problem of creating a new technology that provides the production of asphalt concrete with improved performance.

The problem is solved by the fact that the granular modifying additive includes a modifying mixture and a binder, the modifying mixture consists of single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, carbon nanofibers and mineral powder in the following ratio of components, wt.%:

- single-walled carbon nanotubes - 0.01 - 15,

- multi-walled carbon nanotubes - 0.01 - 15,

- graphene - 0.01 - 15,

- carbon nanofibers - 0.01 - 15

- mineral powder - the rest,

a low-paraffin bituminous binder is used as a binder in the following ratio of components, wt.%:

- modifying mixture 50

- binder 50,

while the resulting granules are dusted with cement or mineral powder, while the mass of cement or mineral powder is not more than 2.5% of the mass of the granules.

The technical result provided by the above set of features is the reduction of time to obtain modified asphalt concrete, as well as the convenience of transporting the modifying additive.

The modifying granular additive is a carbon nanomaterial (CNM) distributed in a mineral powder in the following ratio of components, wt.%:

- single-walled carbon nanotubes - 0.01 - 15,

- multi-walled carbon nanotubes - 0.01 - 15,

- graphene - 0.01 - 15,

- carbon nanofibers - 0.01 - 15

- mineral powder - the rest.

The mixture is produced by distributing carbon nanomaterials in a mineral powder in a ball mill with the possibility of a dry flow process.

The resulting mixture is further granulated. The binder for obtaining the physical strength of the granules is a low-paraffin bituminous binder (MPBV), added in an amount of 50% by weight of the additive mixture.

Single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene and carbon nanofibers are used by any manufacturer and brand.

As a mineral powder, mineral powder MP-1 is used, activated and not activated, corresponding to GOST 32761-2014, GOST R 52129-2003.

MPBV is used as a binder.

The resulting product is granules with a diameter of 5-8 mm and a length of 5-15 mm.

Obtaining a mixture in the form of granules occurs after preliminary mixing of CNM with mineral powder, then the dry mixture is heated in a drum dryer to a temperature of 60-70℃ and fed into the mixer, where the preheated to 60-70℃ MPBV is dosed, mixing occurs until a homogeneous flowing plastics. At the next stage, the plastic mass enters the granulator and at the exit, the finished granules enter the drum rotor for dusting with cement (from PC 250 to PC 400), or mineral dust to give physical strength to the granules, the calculation of the mass of PC or dust is not more than 2.5% of the mass granules. Next, the granules are sent for packaging and labeling.

The use of granules leads to the strengthening of the pavement, improving the performance properties due to the distribution of CNM in the mass of the mineral part of the asphalt when fed into the mixing bin. The use of MPBV as a binder increases the fatigue strength of asphalt.

These granules are used to modify asphalt mix (ABS). When preparing ABS, granules are added directly to the ABS hopper at the final stage of ABS production. The scheme for introducing granules is provided by the technical solution of the ABS manufacturer's plant.

Known methods for modifying bitumen include the introduction of CNM into the oil extract, followed by introduction into the bitumen. These methods are quite costly and require the use of additional equipment, in addition, the time for preparing the modifying composition increases.

The inventive granular modifying additive is a granular dry mix, which is easy to transport to the place of ABS preparation. The dry mixture of mineral powder and CNM is fed into the mill, where all the ingredients are mixed and immediately fed into the mixing hopper with MPBV, then the resulting mass enters the granulator press, where, in accordance with the granulator manufacturer's modes, granules are formed and sent along the conveyor to the rotary inclined hopper for pollination with mineral dust or PC400 (cement). This method of introducing modifying additives does not require additional stages and equipment, while improving the physical and mechanical characteristics of the resulting product.

Also, the advantage of the modifying additive, namely, its implementation in the form of granules, leads to a simplification of the preparation of the asphalt mixture at the asphalt concrete plant (APZ). When introducing pellets to a serial asphalt plant, there is no need to make significant technical changes to the design of the asphalt plant production line. For the supply of granular material, the equipment has a control system that provides dosing of granules, for powdered material there are no such control systems, which complicates the whole process.

The introduction of a modifying additive of various composition (from those listed below) in an amount of 4% by weight of ABS leads to a change in the main indicators of the Marshall samples.

The following are examples of various granular builder formulations.

Example 1. The modifying additive includes:

- single-walled carbon nanotubes - 0.01%,

- multi-walled carbon nanotubes - 15%,

- graphene - 10%,

- carbon nanofibers - 0.01%

- mineral powder - 74.98%.

To form granules, MPBV was added to the resulting mixture of the modifying additive in an amount of 50% of the mixture. Next, the granules were pollinated with cement, with a mass ratio:

Granules - 99.9%

Cement for dusting 0.1%.

Example 2. The modifying additive includes:

- single-walled carbon nanotubes - 7.5%,

- multi-walled carbon nanotubes - 7.5%,

- graphene - 0.01%,

- carbon nanofibers - 15%

- mineral powder - 69.99%.

To form granules, MPBV was added to the resulting mixture of the modifying additive in an amount of 50% of the mixture. Next, the granules were pollinated with cement, with a mass ratio:

Granules - 97.8%

Dusting cement 2.2%.

Example 3. The modifying additive includes:

- single-walled carbon nanotubes - 15%,

- multi-walled carbon nanotubes - 0.01%,

- graphene - 5%,

- carbon nanofibers - 7.5%

- mineral powder - 72.49%.

To form granules, MPBV was added to the resulting mixture of the modifying additive in an amount of 50% of the mixture. Next, the granules were pollinated with mineral powder, with a mass ratio:

Granules - 99%

Mineral powder for dusting 1%.

Example 4. The modifying additive includes:

- single-walled carbon nanotubes - 10%,

- multi-walled carbon nanotubes - 3%,

- graphene - 15%,

- carbon nanofibers - 1%

- mineral powder - 71%.

To form granules, MPBV was added to the resulting mixture of the modifying additive in an amount of 50% of the mixture. Next, the granules were pollinated with mineral powder, with a mass ratio:

Granules - 98%

Mineral powder for dusting 2%.

Example 5. The modifying additive includes:

- single-walled carbon nanotubes - 5.4%,

- multi-walled carbon nanotubes - 8%,

- graphene - 7.5%,

- carbon nanofibers - 5%

- mineral powder - 74.1%.

To form granules, MPBV was added to the resulting mixture of the modifying additive in an amount of 50% of the mixture. Next, the granules were pollinated with mineral powder, with a mass ratio:

Granules - 97.5%

Mineral powder for dusting 2.5%.

Example 6. The modifying additive includes:

- single-walled carbon nanotubes - 2.7%,

- multi-walled carbon nanotubes - 12%,

- graphene - 2%,

- carbon nanofibers - 8%

- mineral powder - 75.3%.

To form granules, MPBV was added to the resulting mixture of the modifying additive in the amount of 50% of the mixture. Next, the granules were pollinated with cement, with a mass ratio:

Granules - 97.5%

Dusting cement 2.5%.

Claims (10)

Granular modifying additive for asphalt concrete, including a modifying mixture and a binder, characterized in that the modifying mixture consists of single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, carbon nanofibers and mineral powder, in the following ratio of components, wt.%: - single-walled carbon nanotubes - 0.01-15, - multi-walled carbon nanotubes - 0.01-15, - graphene - 0.01-15, - carbon nanofibers - 0.01-15, - mineral powder - the rest, as a binder, a low-paraffin bituminous binder is used, with the following ratio of components, wt.%: - modifying mixture 50, - binder 50, while the resulting granules are dusted with cement or mineral powder, while the mass of cement or mineral powder is not more than 2.5% of the mass of the granules.