RU2504565C1 - Road bitumen concrete based on modified asphalt binder - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: bitumen concrete mix includes crushed limestone of 0-5 mm grain size as mineral material, asphalt cement BND 90/130 as a binder, and mechanoactivated lignite as modification agent in the following component ratio, wt %: crushed limestone of 0-5 mm grain size - 93; asphalt - 6.3; mechanoactivated lignite - 0.7.

EFFECT: modification agent increases adhesion properties of crushed stone/binder system thus producing bitumen concrete with good mechanical properties and streamlining and accelerating mix preparation process.

3 tbl, 4 ex

Description

The invention relates to the industry of road-building materials, namely, compositions of mixtures for the manufacture of asphalt concrete, which can be used in the construction of bases and coatings for roads, airfields, bridges. The invention improves the mechanical characteristics of asphalt concrete, simplify the process of preparing the mixture and reduce its duration.

Known asphalt mixture containing bitumen, a modifier including elastomeric chips, petroleum products and mineral aggregate (1. Patent of the Russian Federation No. 2095325 "Asphalt mixture". Aut.KV Rakov, A. P. Safronov). The modifier is the spent swollen elastomeric sorbent of plants for the treatment of industrial wastewater from oil products, in which the ratio of elastomeric crumb: oil products is from 1: 1 to 1: 3, with the following ratio of mixture components, wt.%: Bitumen 5.0-8.0 ; the specified spent sorbent 0.2-2.0; mineral aggregate rest. The elastomeric sorbent is an elastomeric crumb from waste products from rubber products from crosslinked carbochain rubbers with a specific surface area of 10-30 m ² / g with the following fractional composition, wt. fraction less than 1.0 mm - 20-30%; fraction 1.0-2.5 mm - 60-75%; fraction 2.5-3.0 mm - 5-10%.

The proposed fractional composition complicates the process of preparing the asphalt mix, while it is not always possible to achieve a uniform distribution of the elastomeric modifier, which negatively affects the properties of asphalt concrete. In addition, the process of mixing the components of the asphalt mix, the swelling of the elastomeric modifier in bitumen takes a long time (within 3 hours), which increases the duration of the production cycle of the production of asphalt mix.

The closest in technical essence and the achieved result to the claimed invention is asphalt concrete mixture using activated carbon powder as a structuring additive for modifying the binder - tar in the production of asphalt concrete mixture in the following ratio of components, wt.%: Crushed stone - 83; tar - 7; brown coal - 10 (2. Burenina O.N., Nikolaeva L.A., Kopylov V.E. Influence of organo-mineral additives on the properties of binder and asphalt concrete // Collection of international scientific and practical conf. " High technologies, basic research, economics. ”- SPb .: Publishing house of the Polytechnic University, Univ., 2011. V.2. - S.361-365).

Tar-based asphalt mixtures were obtained by mixing the components in a paddle mixer at a rotor speed of 50 r / s. A binder composition is introduced into the pre-heated and crushed limestone crushed stone at 110 ° C. The technology for the preparation of the binder composition consists in drying dispersed brown coals at 110 ° C and then combining with tar previously heated at 90 ° C.

The disadvantage of this technology is the non-compliance with the requirements of GOST 9128-2009 indicators of mechanical characteristics.

The aim of the invention is to improve the quality of asphalt concrete.

The goal is achieved by the fact that as a binder it is proposed to use bitumen BND 90/130, modified by the addition of mechanically activated brown coal in the following ratio of components wt.%: Bitumen - 6.3; mechanically activated carbon - 0.7; crushed stone - 93.

Viscous petroleum bitumen road BND 90/130 (GOST 22245-90) (hereinafter referred to as bitumen) is a mixture of hydrocarbons and heteroorganic compounds and hydrocarbons that does not boil off at oil distillation temperatures (main components: asphaltenes, resins and paraffinic, naphthenic and aromatic base oils ), has the following properties (Table 1).

Table 1 Technical characteristics of bitumen BND 90/130 Name of indicator GOST Penetration, 0.1 mm at temperature: 25 ° C 90-130 0 ° С, not less 28 Temperature, ° С: softening, not lower 43 fragility, not higher -17 flash, not lower 230 Ductility, cm, not less than at temperature: 25 ° C 65 0 ° C 4.0 Change in softening temperature after heating, ° C, not more than 5 Penetration index -1.0 to +1.0

However, the selected bitumen has insufficient crack resistance, is not heat-resistant, inelastic, and does not have the required adhesion to the surface of mineral materials of acidic rocks (3. Gokhman L.M. , 2008 .-- 117 p.).

In order to improve the quality of bitumen and the adhesive ability of the "carbon-binder" system, the introduction of activated brown coal into the bitumen is proposed as a structurally active additive.

Brown coals are typically humic, dense sedimentary rocks (4. Coal base of Russia. Coal basins and deposits of the Far East of Russia. - M .: Geoinformmark CJSC, 1999. T.V. Kn.2. - 638 p.). A prerequisite for the use of dispersed organo-mineral material as a modifying additive for the modification of bitumen in the technology for producing asphalt mixes, in addition to its extensive raw material base and low cost, were its specific properties due to its increased specific surface, developed pore structure, and also high adsorption characteristics (5. Nikolaeva L.A. Brown coal briquetting using modified tar // Diss. For the degree of Candidate of Technical Sciences: 25.00.13. - Irkuts K, 2011 .-- 135 s).

A study of the texture characteristics of brown coals shows that activated brown coal is characterized by a smaller particle size, increased specific geometric surface, as well as an increased number of pores, as can be judged by the increase in specific pore volume compared to non-activated carbon powder (Table 2).

table 2 Lignite texture Indicators Inactive brown coal Activated charcoal The specific pore volume, cm ³ / g 0.013 0.140 Specific geometric surface, m ² / g 2,704 5,440

Studies of the dispersion of fillers show that if the size of individual particles of brown coal before activation is> 180 μm, then after processing in a planetary mill it decreases by two orders of magnitude. Thus, studies have shown that mechanical activation leads to increased adsorption properties and an increase in the dispersion of brown coals.

Limestone crushed stone (hereinafter referred to as crushed stone) is a sedimentary rock consisting mainly of calcium carbonate (calcite), which has the chemical formula CaCO ₃ (6. Kopylov V.E., Nikolaeva L.A. Improving the quality of asphalt concrete through the use of modified oil a binder // Collected Bulletin of the All-Russian Scientific - Ave. Conf. “Living Systems and Structural Materials under Cryolithozone Conditions.” - Yakutsk: NEFU Publishing House, 2011. - P.304-307).

The composition for the asphalt mix is prepared as follows.

The asphalt-concrete mixture includes limestone gravel of a fraction of 0-5 mm as a mineral material, BND 90/130 bitumen as a binder and contains mechanically activated activated brown coal as a structuring additive in the following ratio of components, wt.%:

limestone crushed stone of fraction 0-5 mm - 93

viscous petroleum bitumen - 6.3

activated brown coal - 0.7.

Lignite before mixing with bitumen (oil binder) is dried at 110 ° C to remove part of the residual water and subjected to mechanical activation at the AGO-2 planetary mill with a carrier speed of 630 rpm and a drum of 1290 rpm for two minutes to disperse and increase adsorption capacity. The prepared binder composition is introduced into the pre-heated and crushed limestone crushed stone (fraction size 0-5 mm) and the mixture is mixed at the claimed ratios at a temperature of 140-150 ° C until a homogeneous mixture is formed.

Preparation of the proposed asphalt mix does not require additional devices and appliances. The mixture is easily obtained by mixing its constituent ingredients on standard equipment available in asphalt plants.

The investigated cylindrical samples with a diameter of 50.5 mm and a height of 50.5 mm were tested for compressive strength according to GOST 9128-2009. The results of comparative tests are summarized in table 3. As follows from a comparative analysis of the mechanical characteristics of asphalt concrete, the compressive strength of samples of the proposed composition is higher by about 1.5-3 times compared with asphalt mixtures of known compositions and prototype.

Table 3 Strength characteristics of asphalt concrete No. Structure σ _squ , MPa 0 ° C 20 ° C 50 ° C one Crushed stone 93 wt.% + Bitumen 7 wt.% 13.5 1.8 2.0 2 Crushed stone 83 wt.% + Tar 7 wt.% + Coal 10 wt.% (Prototype) 7.8 1,6 0.8 3 Crushed stone 93 wt.% + Bitumen 6.3 wt.% + Active coal 0.7 wt.% 14.6 6.1 2,8 four GOST 9128-2009 9.0 2,5 1,0

Claims (1)

Asphalt-concrete mixture comprising limestone gravel of fraction 0-5 mm as a mineral material, brown coal as a modifier, characterized in that it contains viscous oil bitumen of the BND 90/130 grade as a binder, and mechanically activated brown coal as a modifier the following ratio of components, wt.%:
limestone crushed stone of fraction 0-5 mm - 93;
viscous petroleum bitumen - 6.3;
mechanically activated brown coal - 0.7.