Composition for strengthening main platform of railway bed

Abstract

FIELD: road construction.SUBSTANCE: invention can be used to strengthen the main platform of a railway bed. A composition is described for strengthening the main platform of a railway bed, comprising fly ash and a binder based on a polymer composite – a colloidal solution of high-molecular compounds, which is a product of polymer-analogous transformations of vinyl polymers in the presence of an alkaline agent and includes a polyelectrolyte introduced into said product, with the following ratio of components, wt.%: fly ash 70.0-80.0, polymer composite 30.0-20.0.EFFECT: targeted improvement of the target functional properties of the material, which is expressed in an increase in the compressive strength limit and, additionally, the presence of optimal thermophysical properties.1 cl, 1 tbl, 6 ex

Description

[0001] The invention relates to the field of road construction and can be used to strengthen the main platform of a railway track.

[0002] A known method for strengthening the base of the roadbed on permafrost soils (RU Patent No. 2074928, published on March 10, 1997), includes the destruction of highly icy fragments with high-speed liquid jets and the removal of the destroyed icy soil with its replacement with a high-consistency pulp based on sand and cement. A known method for repairing a railway roadbed is based on the forced removal of accumulated water through drainage wells by simultaneously injecting cement-clay, cement-sand mortars, or organic binders (RU Patent No. 2277616, published on January 20, 2006). A common disadvantage of the described compositions is that sand-cement mortars can be washed away and carried out of the body of the roadbed.

[0003] A reinforced soil is known for the construction of road bases for highways and transitional type pavements, containing sandy or sandy loam soil, high-calcium fly ash and water (RU Patent No. 2389844, published 2010). The reinforced soil additionally contains ferric chloride and a polymer-containing solution, a waste product from the production of automobile tires, including rubber in the form of DMVP-10X latex in an amount of 7 wt.% and rubber in the form of SKD 1S latex in an amount of 7 wt.%, with the following ratio of components, by weight: sandy or sandy loam soil - 75-77, high-calcium fly ash - 14-16, ferric chloride - 0.13-0.20, the said polymer-containing solution - 0.12-0.17, water - the balance. This reinforced soil for road construction is characterized by comparatively high values ​​of strength, water resistance and frost resistance.However, the use of automobile tire production waste, including rubber in the form of DMVP-10X latex and rubber in the form of SKD 1S latex, as a polymer-containing solution to a certain extent limits the widespread use of this production waste.

[0004] A composition for constructing road bases is known, including as filler: crushed stone of 5-60 mm fraction and crushed stone production waste of 0-5 mm fraction, fly ash from coal combustion, lime production waste (slaked lime), and soap lye (Patent of the Russian Federation No. 2135681, published on August 27, 1999). A disadvantage of this ash-mineral composition is the insignificant mass fraction of binders, which prevent the leaching of heavy metal salts from the road surface into the environment during the initial period of construction.

[0005] A known ash-mineral composition for road pavement bases (RU Patent No. 2350709, published on March 27, 2009) contains sand of fraction up to 3 mm, crushed stone production screenings of fraction up to 10 mm, ash from the incineration of wastewater sludge with a specific surface area of ​​200-300 m as a filler. 2 / kg, bulk density 0.7-0.8 g / m3 3 , SiO2 content 50-60% and pH 12-13.5, with bitumen and cement as binders in the following ratio of components, wt.%: sand fraction up to 3 mm - 10-18; crushed stone production screenings fraction up to 10 mm - 10-15; ash from wastewater sludge incineration - 35-55; petroleum road bitumen - 5-10; Portland cement not lower than 400 - 6-12; water 15-20% of the mixture weight. The disadvantage of this mixture is that the maximum strength of the resulting material is achieved with the introduction of 12% cement into the composition, which is cost-ineffective.

[0006] A composition for road construction is known (RU Patent No. 2603682, published on November 27, 2016) containing, by weight: mineral binder - Portland cement - 6-12; filler (clay soil, sand, crushed stone-sand mixture) - 72-88; chemical additives: octyltriethoxysilane / octyltriethoxysilane emulsion - 0.005-0.04, aqueous solution of a copolymer based on polyoxyethylene derivatives of unsaturated carboxylic acids / carboxylate polyester - 0.02-0.20; water - 4.83-17.94. The technical result of the proposed composition is increased frost resistance and strength of materials made from soil, sand, and crushed stone-sand mixtures, as well as cost-effective construction. A disadvantage of this composition is the need to add 12% cement to obtain a frost-resistant material, which is economically impractical.

[0007] In order to increase the strength, water resistance, and frost resistance during the stabilization of clay soils, it is proposed to introduce a polymerized fatty amine, lime, and coal tar (USSR Author's Certificate No. 487204, published on January 12, 1976) or to use pyridine in an amount of 0.03-0.05% of the dry soil weight (USSR Author's Certificate No. 197446, published on May 31, 1967). However, these methods require the use of highly toxic organic compounds, and the descriptions of these inventions do not contain data confirming the fact of soil strengthening due to the recommended additives.

[0008] The closest in technical solution adopted as a prototype is a composition for increasing the bearing capacity of subgrade foundations (RU Patent No. 2811558, published on 15.01.2024), including man-made soil and a binder based on a polymer composite - poly(1-carbamoylethylene), polyvinyl acetate hydrolysis products, metasilicic acid salts in the following ratio of components, wt.%: man-made soil 70.0-80.0; polymer composite 30.0-20.0. The disadvantages of this composition for increasing the bearing capacity of subgrade foundations are low compressive strength values ​​​​of the road construction material based on it and the lack of thermal insulation properties, which is an important target indicator of materials used to strengthen the subgrade.

[0009] The objective of the invention is to obtain a building material based on ash and slag waste for the construction of a protective layer under ballast, which simultaneously performs reinforcing and frost-protective functions.

[0010] The technical result of the present invention consists in the targeted improvement of the target functional properties of the material, which is expressed in an increase in the compressive strength and, additionally, the presence of optimal thermophysical properties.

[0011] The specified technical result is achieved by the fact that the claimed composition for strengthening the main platform of the roadbed of a railway contains fly ash and a binder based on a polymer composite - a colloidal solution of high-molecular compounds (a product of polymer-analogous transformations of vinyl polymers in the presence of an alkaline agent and a polyelectrolyte) in the following ratio of components, wt.%:

[0012] fly ash 70,0-80,0 polymer composite 30,0-20,0

[0013] Achieving this technical result is due to the participation of hydrogen bonds between the hydroxyl groups of adjacent polymer chains in the formation of the material's structure. Structuring and strengthening of the polymer phase occurs through the formation of additional nodes in the supramolecular network and the emergence of densified regions within the material's structure. The use of a polymer composite as an organic binder increases the material's compressive strength, and the heterogeneity of its pore space, characterized by the presence of fine- and coarse-pored regions, determines its thermophysical properties.

[0014] Characteristics of raw materials:

[0015] 1. Mineral filler - fly ash according to GOST R 57789-2017.

[0016] 2. Organic binder - a polymer composite based on high-molecular compounds (a product of polymer-analogous transformations of vinyl polymers in the presence of an alkaline agent and a polyelectrolyte).

[0017] The composition for strengthening the main platform of the railway roadbed was developed in accordance with GOST 30491-2012 by selecting the optimal amount of binder as a percentage of the fly ash mass. The main criteria for evaluating the composition's optimality were compressive strength and thermal conductivity.

[0018] Example. An organic binder—a polymer composite based on high-molecular compounds (a product of polymer-analogous transformations of vinyl polymers in the presence of an alkaline agent and a polyelectrolyte)—was added to air-dried fly ash, after which the mixture was mixed manually. Cylindrical specimens with a diameter of 50.5 mm and a height of 50 mm were made from each type of the resulting mixture. Strength characteristics were obtained in accordance with GOST 30491-2012 on specimens after exposure to air at a temperature of 20 ± 2 °C. Thermal conductivity of the specimens was determined using a MIT-1 thermal conductivity meter using a probe method based on measuring the change in probe temperature over a specified time when heated at a constant power. Probe diameter: 6.0 mm. The probe was placed inside cylindrical samples with a diameter of 100±5 mm, ensuring maximum thermal contact between the probe and the sample. For this purpose, a hole with a diameter of 6+0.1 mm and a depth of 100 mm was drilled.

[0019] The physical and mechanical characteristics of the obtained samples are given in Table 1. It was found that the introduction of a polymer composite based on high-molecular compounds (a product of polymer-analogous transformations of vinyl polymers in the presence of an alkaline agent and a polyelectrolyte) into the composition for strengthening the main platform of the railway roadbed makes it possible to obtain a road construction material with a compressive strength of 7.50-7.80 MPa and a thermal conductivity of 0.17-0.18 W / (m⋅K).

[0020]

[0021] A comparative analysis with the prototype shows that the claimed composition for strengthening the main platform of a railway roadbed allows for the production of a road construction material with a thermal conductivity of 0.17-0.18 W / (m⋅K) and a compressive strength of 7.50-7.80 MPa, whereas the prototype is not a thermal insulating material and has a compressive strength of 6.00-6.70 MPa. This difference from the prototype provides grounds for asserting that the proposed technical solution meets the patentability criterion of "novelty." A comparison of the claimed composition for strengthening the main platform of a railway roadbed with other similar technical solutions in this field did not reveal any features similar to the distinctive features. This allows us to conclude that the claimed composition for strengthening the main platform of a railway roadbed meets the patentability criterion of "inventive step."

[0022] Thus, the use of the proposed invention makes it possible to obtain an effective road-building material for strengthening the main platform of a railway roadbed with a compressive strength of 7.50-7.80 MPa and a thermal conductivity of 0.17-0.18 W / (m⋅K).

Images