RU2401817C1 - Asphalt mix modifier - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: invention relates to road construction materials and can be used when paving roads, bridges and aerodromes in all climatic zones. The modifier contains the following components - vulcanised rubber and a composite of modifying components in weight ratio of: calcium metasilicate with needlelike structure 24%, epoxy resin 2%, nitrosoamine compound 1%, phenol resin and/or colophony 4%, vulcanised rubber (rubber crumps) 69%. ^ EFFECT: improved quality factors of the asphalt mix. ^ 3 tbl

Description

The invention relates to road-building materials and can be used for paving roads, bridges, airfields in all climatic zones. The invention relates to improving the quality indicators of the asphalt mix by introducing a modifier into it as a structuring additive.

Known asphalt mixtures containing sand, mineral powder, gravel, petroleum bitumen and stabilizing or structuring additives (GOST 31015-2002, RF patent No. 2196750).

The closest in technical essence and the achieved result to the present invention is asphalt concrete mixture according to the patent of the Russian Federation 2196750, including sand, mineral powder, polymer structuring additive and petroleum bitumen, characterized in that it contains viscous petroleum bitumen, it contains a rubber thermoplastic elastomer and additional surface-active plasticizing additive - tall pitch and screening crushing crushed stone fractions of 0-5 mm, in the following ratio of components, wt.%:

Sand - 16.0-20.0

Mineral powder - 10.0-15.0

Rubber thermoplastic elastomer - 0.5-1.0

Oil Viscous Bitumen - 5.0-6.5

Tall pitch - 0.3-0.5

Screening crushing crushed stone fraction 0-5 mm - 57.0-68.2.

Structuring additive in the patent of the Russian Federation No. 2196750 adopted as a prototype.

A disadvantage of the known solution is the relatively low strength index of asphalt mixtures with a structuring additive in the form of rubber thermoplastic elastomer and gall pitch at 50 ° C (1.31-1.65 MPa), which characterizes the heat and shear stability of the mixtures, which is especially important for the southern regions of the country. Another disadvantage is the low-tech preparation of mixtures due to the need to pre-modify bitumen with tar pitch.

The technical result of the claimed invention is to reduce the temperature sensitivity and increase fatigue life with increasing water resistance, frost resistance, resistance to the effects of water-salt solutions, strength in the water-saturated state and at + 50 ° C (table 2), lower viscosity and increase ductility at low temperatures , as well as the possibility of manufacturing asphalt mixes with the proposed modifier without changing the standard technology for the production of asphalt mixtures. In addition, the technical result is the ease of use of the proposed modifier in the manufacture of asphalt mixtures, which, ultimately, reduces the cost of road surface.

The essence of the claimed invention lies in the fact that, in contrast to the known solution, the vulcanized non-polar rubber in the form of crumb rubber (mainly from waste tires) is used as an elasticizing component as a structuring additive, and the structure of the bitumen binder is achieved by a composite of modifying components, which includes :

- needle-shaped calcium metasilicate - a strengthening and structure-forming component;

- epoxy resin - a crosslinking agent;

- nitrosoamine compound - gelling agent;

- phenolic resin and / or rosin - adhesive.

The content of modifying components is determined empirically based on existing knowledge of asphalt binder in asphalt concrete and the chemical interaction of bitumen with the mineral components of asphalt concrete and vulcanized rubber. The optimization of the number of components was checked on the basis of the analysis of experimental selection of asphalt concrete compositions by changing their strength, crack resistance, water resistance and workability.

The ratio of the components of the inventive modifier are presented in table 1.

The inventive modifier can be made in the form of a dry mixture and delivered to enterprises manufacturing asphalt mix in a metered-dose package. In the manufacture of asphalt mix, the modifier is introduced in the form of a dry or wet powder.

The asphalt mix is made by known methods in mixing plants equipped with batch or continuous forced mixers. The modifier is introduced directly into the mixer, during or after the introduction of bitumen. The minimum mixing time of the main part of the asphalt mix with this composite is 25 seconds. Mixing time is set in accordance with the technical characteristics of the existing mixing plant and, if necessary, is specified during the experimental batch. The modifier does not require heating before being fed into the mixer.

The proposed modifier allows to obtain a qualitatively new composition of the asphalt concrete composition in which rubber is chemically and physically bonded to the remaining components of the entire composition without preliminary degradation by heating in bitumen at high temperatures, as well as significantly improve the rheological and operational characteristics of asphalt concrete:

- in terms of reducing temperature sensitivity and increasing fatigue life, with an increase in water resistance, frost resistance, resistance to the effects of water-salt solutions, strength in a water-saturated state and at + 50 ° C (table 2);

- in terms of reducing viscosity and increasing ductility at low temperatures (table 3).

At the same time, all the known advantages of rubber-asphalt coatings are retained, namely, an increase in the service life, a decrease in rutting, a decrease in noise when driving vehicles, a decrease in the stopping distance, a decrease in the thickness of a water film and an improvement in water rolling, a decrease in all types of crack formation, etc.

In contrast to the prototype, the modifier preparation technology consists in simple mixing of the components in the claimed proportions.

Table 1 Function (purpose) Material type Content in% by weight of the total composition of the modifier hardening and structure-forming component needle calcium calcium metasilicate 24 crosslinking agent epoxy resin 2 gelling agent nitrosoamine compound one adhesive phenolic resin and / or rosin four elastic component rubberized vulcanized non-polar rubber 69

Table 2 Indicators The proposed composition The control mixture that meets the requirements of GOST Known according to patent RU 2196750 Fatigue life at -18 ° C (number of cycles to failure) 8255 1042 - Fatigue life at + 20 ° C (number of cycles to failure) 25284 18718 - Tensile strength at compression at 20 ° C, MPa 5.1 3.9 4.37-5.87 Tensile strength at compression at 50 ° C, MPa 3.8 1.3 1.31-1.65 Frost coefficient 0.78 0.68 - The coefficient of resistance to the effects of water-salt solutions Kv-s 0.75 0.69 - Water Resistance 0.97 0.85 0.85-0.99 Compressive strength in a saturated state, 20 ° C, MPa 5,0 3.8 - Water resistance at long water saturation, Kdl 0.97 0.85 + 14%

Tab. 3 No. n / a composition Temperature ° C Load Q, kg Viscosity, η Poise The degree of plasticity, P Modulus of elasticity, E (kg / s ² ) Elastic modulus E (MPa) Known mixture according to GOST (control) +20 2,553 2.17E + 11 0.370 24,297.89 2429.79 -eighteen 17,700 1,05Е + 12 0.332 29472.40 2947.24 Proposed +20 2,050 1.22E + 11 0.384 22645.85 2264.60 -eighteen 14.55 5.42E + 11 0.351 27029,00 2702.90

Claims (1)

A modifier of the asphalt mix containing vulcanized rubber and a composite of modifying components, consisting of needle-shaped calcium metasilicate, epoxy resin, nitrosoamine compound, phenolic resin and / or rosin, which are in a ratio by weight,%:
needle calcium calcium metasilicate 24 epoxy resin 2 nitrosoamine compound one phenolic resin and / or rosin four vulcanized rubber (crumb rubber) 69