RU2262492C1 - Bituminous concrete composition - Google Patents

Abstract

FIELD: highway engineering, in particular paving upper layers building in all climatic regions.

SUBSTANCE: claimed bituminous concrete composition contains (mass %): lime chip of 5-20 mm fraction 35-45; petroleum viscous bitumen 5.0-5.5; mineral powder from dolomite or lime rocks 3-8; polymer additive 0.1-0.25 based on bitumen mass and balance: sand of 5 mm or less fraction. As said polymer additive polyethylene terephthalate in form of secondary plastic bottles is used.

EFFECT: bituminous concrete with improved structure-forming characteristics and increased water and heat resistance.

1 cl, 4 tbl, 1 ex

Description

The invention relates to the construction of roads and can be used for the device of the upper layers of pavement in all climatic zones.

In the construction of roads, asphalt mixtures prepared in accordance with GOST 9128-97 and polymer-asphalt concrete based on block copolymers of butadiene and styrene like SBS (Voronezh Synthetic Rubber Plant), as well as many of their foreign analogues OST 218.010-98, are widely used.

Known asphalt mixture (AS No. 903450, E 01 C 7/18, 1982), including: petroleum bitumen, synthetic rubber (waste styrene-butadiene rubber), plasticizer and mineral filler (crushed stone and sand). Such a mixture has many advantages inherent in polymer-asphalt concrete.

However, the disadvantages of this mixture is the high consumption of bitumen - up to 17.6%; insufficient compressive strength at 50 ° C (1.61-1.62 MPa) and a low value of water saturation.

Closest to the proposed invention in terms of technical nature and the achieved result is an asphalt mixture (as.with. No. 2119465, class C 04 B 26/26, 1998), including, wt.%:

oil bitumen 5-6.5 synthetic oil solution high molecular weight polybutadiene rubber (polymer additive) 0.15-0.30 sludge chemical water treatment CHP 2-4 limestone crushed stone fractions 5-20 mm 25-35 mineral powder (from dolomite or limestone rocks) 1-3 sand fractions up to 5 mm rest

The introduction of a rubber-based polymer additive in the composition of petroleum bitumen and additionally in the composition of the mineral material of chemical water treatment sludge (instead of mineral powder) reinforce the process of formation of asphalt concrete, increasing its water and heat resistance.

The disadvantage of this mixture is the increased cost due to the use of an expensive polymer additive (≈ 40 thousand rubles per ton), poor adhesion of bitumen to dry mineral material and lack of adhesion to wet mineral material.

The invention is aimed at improving the basic characteristics of the physicomechanical properties of the asphalt concrete mixture, reducing the consumption of its expensive components: bitumen and polymer additives, as well as reducing environmental damage through the disposal of household waste: used plastic bottles made of polyethylene terephthalate (PET).

The essence of the invention lies in the fact that in the asphalt mixture containing limestone gravel fractions 5-20 mm, sand fractions up to 5 mm, mineral powder (from dolomite or limestone rocks), viscous petroleum bitumen 5-6 wt.% And polymer additive, as the latter, secondary polyethylene terephthalate is used in the form of used plastic bottles in the following ratio of components, wt.%:

limestone crushed stone fr. 5-20 mm 35-45 oil viscous bitumen 5.0-6.0 mineral powder 3-8 specified polymer additive 0.1-0.25 by weight of bitumen sand fractions up to 5 mm rest

The introduction of a polymer additive in the form of recycled polyethylene terephthalate (used plastic bottles) into the composition of petroleum road bitumen gives the asphalt concrete mixture new properties by increasing the adhesion of bitumen with mineral components, as polyethylene terephthalate contains polar ester groups that contribute to better adhesion of bitumen even to the wet surface of the mineral material.

This allows you to strengthen the processes of structure formation of asphalt concrete and improve the basic physical and mechanical characteristics of its properties (see table 1).

The proposed asphalt mixture is cheaper, because the above polymer additive is household waste, and the cost of the polymer additive of the prototype is ≈40 thousand rubles. per ton. At the same time, used plastic bottles made of polyethylene terephthalate are utilized and the costs of expensive components: bitumen and polymer additives are reduced.

Characterization of raw materials

1. Secondary polyethylene terephthalate, TU-6-05-1984-85, grade 277-73, is used plastic bottles. This is a thermoplastic material, melting point 243 ° С, softening temperature 100 ° С, molecular weight 20000-40000, melt flow rate 1.5-2 g / 10 min, breaking stress at break 134.5 MPa, tensile modulus 6130 MPa, insoluble in water and organic solvents, soluble in phenols and its alkyl derivatives.

2. Limestone crushed stone fraction 5-20 mm.

As limestone crushed stone used limestone deposits "Apanasovsky quarry" of the Rostov region. Tables 2, 3 show the chemical and grain composition of crushed stone and sand.

3. The sand.

As sand, screening of crushing limestone crushed stone fractions up to 5 mm was used.

4. Astringent.

As a binder, BND 90/130 oil road bitumen was used. Table 4 presents its physical and mechanical properties in comparison with a polymer-bitumen binder. In terms of physical and mechanical properties, the initial bitumen meets the requirements of GOST 22245-90.

5. Mineral powder.

Fine mineral powder of dolomite or limestone rocks is used as a mineral powder.

Example. For experimental verification of the claimed composition were prepared 6 variants of mixtures prepared from the above ingredients. Samples were prepared as follows: bitumen with the addition of secondary polyethylene terephthalate was introduced into preheated materials up to 160 ° С (limestone crushed stone, sand and mineral powder). The mixture was stirred in a laboratory stirrer for 5 minutes at a temperature of 140-160 ° C until a homogeneous composition was formed. Then, samples with a diameter of 70.1 mm under a pressure of 40 MPa were prepared from it. One of the mixtures was made on bitumen BND 90/130 without the addition of polyethylene terephthalate, the remaining five with its different percentages (0.05; 0.10; 0.20; 0.25; 0.30). From the comparative tests and analysis of the results found that the asphalt mixture of the proposed composition has better physical and mechanical properties compared with the mixture prepared on bitumen without additives, but is close in its properties to the mixture of the prototype.

The best performance of the proposed asphalt mixture was observed with the introduction of secondary polyethylene terephthalate in the range from 0.10 to 0.25% by weight of bitumen. Moreover, the optimal value was 0.20%.

The results of the comparative analysis are summarized in table 1.

Therefore, the main advantage of the proposed asphalt mix is the improvement of its quality by improving the adhesion of the binder with mineral components, increasing water and heat resistance, and as a result, increasing resistance to dynamic loads.

Table 1 Physico-mechanical properties of type B asphalt concrete grade II of the fourth climatic zone and polymer-asphalt concrete prototype and made from the proposed mixture No. Name
indicators Asphalt
GOST concrete
9128-97 Fact. type with bitumen BND
90/130 Asphalt concrete From the proposed mixture Prototype 1 Strength at 20 ° С R ₂₀ , MPa not less 2,5 4.1 4.75 4.17 2 Strength at 50 ° С R ₅₀ , MPa not less 1.3 1.71 2,50 2.49 3 Strength at 0 ° С R ₀ , MPa no more thirteen 12.1 14.0 7.98-8.29 4 Water saturation 1.5-4.0 2.6 1,60 1.15-2.96 5 Water resistance coefficient not less than 0.85 0.94 0.98 0.97-0.99 6 Water resistance coefficient during long-term water saturation 0.75 0.7 0.80 0.95 7 Residual porosity,% 3-7 2.7 2,5 8 The porosity of the mineral core,% no more 19 15.8 14.3 nine Density 2.45 2,4 2,31 10 Bitumen consumption 5.3 5.20 5-6.5

table 2 The chemical composition of limestone crushed stone mass content,% RFP SiO ₂ R ₂ O ₃ Fe ₂ O ₃ Al ₂ About ₃ + TiO ₂ CaO MgO SO ₃ 46.85 1.68 1,63 0.59 1,04 47.05 2,55 0.24

Table 3 Grain compositions of mineral materials Name of material Mass fraction,% grains of mineral material finer, mm twenty fifteen 10 5 2,5 1.25 0.63 0.315 0.14 0,07 Limestone crushed stone 92.4 81.8 69.6 12.0 1,5 1.4 1.3 1,2 1,1 1,0 Sand - - - 100 87.6 66,2 47.3 30,4 17.4 10,4 Mineral powder from dolomite rock - - - - - 100 99.5 99.1 79,4 20.1

Table 4 Physico-mechanical properties of bitumen and polymer-bitumen binder (PBB) using secondary polyethylene terephthalate. No.
p / p Name of indicator Bitumen PBB GOST
222245-90 BND fact
90/130 OST
218.010-98 The fact is optim. Sample 1 The penetration depth of the needle is 0.1 mm at 25 ° C, 91-130 120 not less than 90 96 at 0 ° С not less than 28 thirty not less than 40 99 2 Elongation (cm) at 25 ° С, not less than 65 70 not less than 30 100 at 0 ° C not less than 4.0 7.2 not less than 15 7.8 3 Softening point, ° С not lower than 43 46 not lower than 51 48 4 Marble adhesion tests not normal. not pulled out. (sat.) Aging by control. patterned Fine 5 Fraas fragility temperature, ° С not higher
-17 -19.5 no higher than 25 -22.5 6 Flash point, ° С not lower than 230 273 not lower than 220 > 270 7 Uniformity - uniformly Stand after 40 minutes cooked. Uniformly

Claims (1)

Asphalt-concrete mixture for road construction, containing limestone gravel fractions 5-20 mm, sand fractions up to 5 mm, mineral powder, viscous petroleum bitumen and a polymer additive, characterized in that secondary polyethylene terephthalate in the form of used plastic bottles is used as a polymer additive the following ratio of components, wt.%: limestone crushed stone fractions 5-20 mm 35-45 oil viscous bitumen 5.0-5.5 mineral powder from dolomite or limestone rocks 3-8 specified polymer additive 0.1-0.25 by weight of bitumen sand fractions up to 5 mm rest