RU2341479C1 - Cast road concrete mix for bridge drive way covering - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: cast asphalt mix for drive way covering of bridge contains the following components - ballast stone, sand, mineral powder and binding agent. It also comprises additional mineral component such as sand resulted from rock granulation screening and polymer bitumen as binding agent, wt %: bitumen "BND90/130" - 87-91%, styrene-butadiene-styrene block-copolymer "Kraton D-1101SM" - 9-13% under the following ratio of components, wt %: ballast stone - 35-41, sand resulted from granulation screening - 10-20, sand - 6-16, mineral powder - 20-26, sand resulted from granulation screening - 10-16.

EFFECT: high long-term operational characteristics of covering preventing formation of defects such as tracks on driving lines and waves along longitudinal section of road.

3 tbl, 3 ex, 2 dwg

Description

The invention relates to the field of construction, namely, compositions of cast asphalt mixtures used in civil, road, airfield, hydraulic and other types of construction. Cast asphalt mix can be used mainly for the device of the upper layer of pavement of the carriageway of bridges and overpasses.

Known compositions of asphalt used in the construction of transport facilities - highways, highways, city or country roads, airfields, moorings, access roads, parking areas, city squares, sidewalks, overpasses, bridges and / or tunnels. All compositions contain bitumen or a polymer-bitumen binder, crushed stone, mineral powder and sand [patents for the invention of the Russian Federation No. 20111727, 2135671, 2119465].

However, the compositions of asphalt given in the patents do not provide the cast structure of the mixture.

Also known asphalt mixture, prepared by mixing at 140-160 ° C gravel, sand, mineral powder, bitumen and polymer additives. When this mineral powder is taken initially 8-10 wt.%. After mixing and cooling to 30-40 ° C, 1-4 wt.% Of the mineral powder of the asphalt concrete mixture is added to the mixture, and a pre-prepared polymer additive is added to the resulting concentrate in an amount of 1-2% by weight of the asphalt concrete mixture. The polymer additive consists of mineral oil and a polymer, which is used divinyl styrene thermoplastic or chloroprene rubber, a cationic or anionic surfactant, bitumen in the following ratio, wt.%: Bitumen 10-15, polymer 2-4, surfactant 0, 5-1, mineral oil - the rest is up to 100 [patent for the invention of the Russian Federation No. 2154039, IPC SB04/26].

However, the parameters of the resulting mixture do not meet the requirements for road pavement of bridges: strength, crack resistance, shear resistance, absolute waterproofness.

Also known asphalt mixture prepared from the following components,%: crushed stone fraction 5-15 granite - 14, natural sand - 69, mineral powder - 17, bitumen by weight of mineral materials - 5, sulfur in powder form, by weight of mineral materials - 5 [patent for the invention of the Russian Federation No. 2197445, IPC SB04/26].

However, when using sulfur in the composition of asphalt mixtures for pavement, hydrogen sulfide is released at different stages of the process, which has a negative effect on the composition of the atmosphere of the working area, the health of the staff and the environment. In addition, sulfur is not an ideal modifier for bitumen.

The closest analogue to the claimed invention is a mixture of paved asphalt, intended for the repair of pavements, including patches, for sealing damages at manholes and for laying coatings along tram tracks. This mixture contains,%: crushed stone 41-48; sand 17-29; mineral powder 10-22 and bitumen 8.9-11. The amount of bitumen in each specific mixture is calculated according to a certain formula [patent for the invention of the Russian Federation No. 2062762, IPC С04 В 26/26, С04В 111/20].

However, the ratio of mineral components in this mixture is selected exclusively for patching or work on small areas and the mixture is not suitable for the construction of a long roadway. The use of bitumen grade BND 40/60 in this mixture does not provide the required crack resistance of the road surface in winter. The absence of an intermediate fraction of stone material does not allow to obtain a uniform and durable skeleton of the coating, which affects the performance. In addition, the adhesion of the wheels of cars with a coating of cast asphalt is not adequately ensured.

The objective of the invention is to create a mixture for a continuous coating device with crack resistance in the winter and high shear resistance and durability in summer conditions.

The technical result of the claimed invention is to create a coating that maintains high performance for a long period and prevents the formation of defects such as ruts along the runways and waves in the longitudinal section of the road. Moreover, the coating meets all the requirements for the construction of coatings for bridge structures.

The problem is solved in that the mixture for cast asphalt for paving the roadway of the bridge containing mineral components - crushed stone, sand, mineral powder and binder - bitumen, according to the proposed solution, contains an additional mineral component - sand from crushing screenings, as a binder use a polymer-bitumen binder in the following ratio of components wt.%:

crushed stone - 35-41,

sand from crushing screenings - 10-20,

sand - 6-16,

mineral powder - 20-26,

polymer-bitumen binder - 10-16.

In addition, the number of mineral components from the interval of the selected values is determined by constructing the limit curves and the sieving curve of the mineral components on sieves with fixed hole sizes, mm: 20, 16, 12, 8, 5.6, 4, 2, 1, 0.5 0.25, 0.125, 0.063.

In the polymer-bitumen binder, components are used in the following ratio, wt.%: Bitumen "BND90 / 130" - 87-91%, styrene-butadiene-styrene block copolymer "Kraton D-1101CM" - 9-13%.

The proposed solution is illustrated in figure 1 and figure 2, which are indicated: 1, 3 - limit graphs, 2 - graph of the dependence of the total number of components from the fraction.

Cast asphalt mix includes a polymer-bitumen binder, mineral components - crushed stone with a grain size of fractions of 5-20 mm, sand from screenings of crushing with a grain size of fractions of 0.01-5 mm, river sand and mineral powder at the above ratio.

Cast asphalt mixture for the device of the road surface of the carriageway of the bridge is prepared as follows. The listed components are placed in a cyclic asphalt mixer and mixed at a temperature of 180 ° C for 2.5 minutes. After mixing, the mixture is loaded into Kocher, the temperature is raised to 210 ° C and transported to the place of laying. Laying is carried out at a working temperature of the mixture 180-210 ° C. The maximum residence time of the mixture in Kocher at operating temperature is not more than 48 hours. In this case, the mixture is periodically mixed to prevent delamination and local overheating.

In the manufacture of a polymer-bitumen binder, bitumen and polymer are used. The use of BND 90/130 bitumen according to GOST 22245-90 as a starting material is due to its availability, relatively low viscosity, which allows for the best dissolution of the polymer and its other parameters. As the polymer selected styrene-butadiene-styrene block copolymer "Kraton D-1101 CM" company Shell. A polymer-bitumen binder is obtained by dissolving the polymer in bitumen in the following percentage by weight: bitumen “BND90 / 130” - 87-91%, styrene-butadiene-styrene block copolymer “Kraton D-1101CM” - 9-13%.

The amount of mineral components in the mixture can be selected by the method of constructing limit curves, in accordance with which the particle size distribution of each initial mineral component is determined, for which they are sieved on sieves with holes, the dimensions of which are the following values, mm: 20, 16, 12, 8, 5,6, 4, 2, 1, 0.5, 0.25, 0.125, 0.063.

Based on the results obtained, a graph is plotted for the dependence of the total number of components on the fraction (curve 2 of Fig. 1, 2) and limit graphs (curves 1, 3 of Fig. 1, 2) established by the Standard of the enterprise. If the resulting schedule runs smoothly between the limits, consider the selection of mineral components complete. If the resulting graph crosses the limit curves 1 and 3, then the ratio between the component materials is changed.

Example 1. Made 5 mixtures with different amounts of components shown in table 1. The number of components reduced to 100%. The binder is taken in excess of 100%, the polymer-bitumen binder PBV 100 is used as the binder.

Table 1 Mix No. The content of components,% by weight Test results Shear resistance on a stamp at 25 ° C, mm Mineral powder Sand Screening crushing Crushed stone Polymer-bitumen binder Actually According to the norm one 26 12 eighteen 44 8 0.21 2-9 2 26 10 eighteen 46 10 2.25 3 26 12 eighteen 44 12 5.51 four 26 12 twenty 42 fourteen 7.51 5 26 12 eighteen 44 16 9.71

The table shows that the compositions of mixtures No. 2, 3, 4 provide the main parameter that determines the quality and properties of the resulting cast asphalt concrete mix - shear resistance to punch at 25 ° C. For cast asphalt mixtures used for coating on the roadway, it should be in the range of 2-9 mm. Composition No. 1 has a die shift resistance of 0.21 mm, which is below the norm. Composition No. 5 has a stamp resistance of 9.71 mm, which exceeds the norm. Compositions of asphalt concrete from a mixture of No. 1 and 5 do not satisfy the required properties.

Example 2. The inventive method was made a mixture with the amount of crushed stone - 44 wt.%, Sand from the screenings crushing - 18 wt.%, Sand - 12 wt.%, Mineral powder -26 wt.%. The number of components is reduced to 100%. The binder is taken in 11 wt.% In excess of 100%. When translating the amount of mineral components and a binder to 100%, the number of components is accepted: crushed stone - 39 wt.%, Sand from the screenings of crushing - 16 wt.%, Sand - 11 wt.%, Mineral powder - 23 wt.%. At the same time, the amount of mineral components of a certain fraction (indicated in table 2) ensured the composition of the mixture that satisfies all the requirements.

table 2 Name of materials % Full passages,% by weight, on sieves with holes twenty 16 12 8 5,6 four 2 one 0.5 0.25 0.125 0,063 Crushed stone Orsky 5/20 44 44 41.2 25.3 10.7 3.9 0.4 0.2 Screening Pavlovsky eighteen eighteen eighteen 17.8 17.8 17.7 16.8 12,4 9.1 6.7 4.9 3.6 2.6 Sand 12 12.0 12.0 12.0 12.0 11.9 11.9 11.9 11.9 11.3 3.9 0.1 0,0 Min powder 26 26 26 26 26 26 26 26 26 26 26 25.8 20.8 Total one hundred 97.2 81.2 66.5 59.5 55,2 50,5 47.0 44 34.8 29.6 23.5

For this composition, the graph (figure 1) of the dependence of the number of mineral components on fraction 2 does not intersect the limit graphs 1 and 3. The upper and lower graphs reflect the dependence of the maximum and minimum amounts of mineral material on a given fraction. The average graph is the actual result obtained when testing these materials in predetermined proportions during sieving, shown in table 2. The parameters of the proposed cast asphalt concrete mix meet the requirements.

In the manufacture of the proposed cast asphalt mixture, cube-shaped crushed stone of a fraction of 5-20 mm in accordance with GOST 8269-87, sand from crushing screenings in accordance with GOST 8736-93, river sand Mkr≥1,2 in accordance with GOST 8736-93, mineral powder in accordance with GOST R 52129- 2003 and a polymer-bitumen binder (consisting of styrene-butadiene-styrene polymer Kraton D-1101 - 9 wt.% And bitumen "BND 90/130" according to GOST 22245-90-91 wt.%). Mixing of the components was carried out for 2.5 minutes at a temperature of 180 ° C, the mixture was laid at a temperature of 210 ° C. The resulting layer of cast asphalt mix has high strength, shear resistance, crack resistance and water resistance. In addition, through the use of mineral components with various fractions, a more solid layer skeleton was formed.

Example 3. Made cast asphalt mixture containing mineral components, the amount of which (reduced to 100%) is shown in table 3.

Table 3 Name of materials % Full passages,% by weight, on sieves with holes twenty 16 12 8 5,6 four 2 one 0.5 0.25 0.125 0,063 Crushed stone Orsky 5/20 fifty fifty 46.9 28.8 12,2 4,5 0.5 0.2 Screening Pavlovsky 25 25 25 24.8 24.7 24.5 23,4 17,2 12.6 9.3 6.8 5 3,7 Sand 12 12 12 12 12 11.9 11.9 11.9 11.9 11.3 3.9 0.1 Min powder 13 13 13 13 13 13 13 13 13 13 13 12.9 10,4 Total one hundred 96.9 78.6 61.9 53.9 48.8 42,4 37.5 33.5 23.7 18.1 14.1

For this composition, the graph (figure 2) of the dependence of the fraction of mineral components on their number 2 crosses the lower 1 limit graph.

The parameters of the proposed cast asphalt mix do not meet the requirements for road surfaces: crack resistance, shear resistance, etc.

Cast asphalt mixtures prepared using a polymer-bitumen binder have high resistance to elastic deformation and fatigue manifestations. This ensures the durability of the coating. In addition, the proposed mixture has high mobility at a laying temperature and is capable of self-leveling after distribution in the pavement and, after cooling, naturally formed into an elastic monolith of increased density.

In the manufacture of the proposed cast asphalt mix, cube-like crushed stone of a 5-20 mm fraction was used according to GOST 8269-87 - 39 wt.%, Sand from crushing screenings according to GOST 8736-93 - 16 wt.%, River sand Mkr≥1,2 according to GOST 8736 -93 - 11 wt.%, Mineral powder according to GOST R 52129-2003 - 23 wt.%, Polymer-bitumen binder (consisting of styrene-butadiene-styrene polymer Kraton D-1101 - 9 wt.% And bitumen "BND 90 / 130 "according to GOST 22245-90 - 91 wt.%) - 11 wt.%. Mixing of the components was carried out for 2.5 minutes at a temperature of 180 ° C, laying the mixture was carried out at a temperature of 210 ° C. The resulting layer of cast asphalt mix has plasticity, water resistance, special strength and is able to recover deformations from the application of concentrated loads.

Claims (1)

A mixture of cast asphalt for paving the roadway of the bridge, containing mineral components - crushed stone, sand, mineral powder and binder, characterized in that it contains an additional mineral component - sand from screenings of crushing rocks, as a binder use a polymer-bitumen binder composition , wt.%: bitumen "BND90 / 130" 87-91 styrene-butadiene-styrene block copolymer "Kraton D-1101SM" 9-13 in the following ratio of components, wt.%: crushed stone 35-41 sand from crushing screenings 10-20 sand 6-16 mineral powder 20-26 specified polymer-bitumen binder 10-16

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