RU2750536C1 - Composition for the arrangement of functional layers of the roadbed - Google Patents

Abstract

FIELD: road construction.

SUBSTANCE: invention relates to road construction and can be used to create functional layers of the roadbed by complex strengthening of local soils in the construction of roads and railways. The invention is aimed at improving the physical and mechanical characteristics of the composition for arranging functional layers of the roadbed due to the use of a complex binder obtained by joint grinding of Portland cement clinker and additives of various functional purposes and the qualitative introduction of the polymer component into its composition. The composition for the arrangement of functional layers of the roadbed contains soil, binder and water. In this case, the soil is used in the form of loam with a plasticity index under 12, the binder is used in the form of a complex binder obtained by joint grinding of Portland cement clinker, gypsum, anionic oligomer such as Melment F10 additive, wollastonite, active silica with a specific surface area of 450 m2/kg with a ratio of materials 17:1:0.2:1.7:0.1; at the following ratio of the components of the composition, mass percentage: loam 72-76, complex binder 8-10, water the rest.

EFFECT: better physical and mechanical characteristics of the composition for arranging functional layers of the roadbed.

1 cl, 1 tbl

Description

The invention relates to road construction and can be used to create functional layers of the subgrade by comprehensive strengthening of local soils during the construction of roads and railways. The functional layers include: frost-protective layer, heat-insulating layer, working layer - for highways; protective layer - for railways.

Known "Composition for road construction", which contains masses. %: Portland cement - 6-12, aggregate - 72-88, 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. [Patent RU for invention No. 2603682 publ. 11/27/2016 Bul. No. 33].

The disadvantages of this invention are the low physical and mechanical properties of the composition. The decrease in the quality of the final material is affected by the use of an emulsion of octyltriethoxysilane and polymer, their use in liquid form requires additional adjustment of the mixture due to the natural moisture content of the soil, which also negatively affects the quality of the final product.

The closest to the claimed invention, the technical solution adopted for the prototype is "Composition for the device of the bases of pavements and other engineering structures", containing sand from screenings of crushing fraction of 0-5 mm (soil); mineral binder - Portland cement with mineral additives; hydrolysis lignin; polymer composite in the form of a colloidal solution of high molecular weight surfactants: poly (2-propenamide) and polyvinyl acetate hydrolysis products in the following ratio of components, wt. %: sand from crushing screenings - 82-85; hydrolysis lignin - 5-2; Portland cement - 8-6; polymer composite - 0.4-0.8 (over 100%); water - 5-7. [Patent RU for invention No. 2726094 publ. 07/09/2020 Bul. No. 19].

The disadvantage of this composition is that it has low physical and mechanical properties. Also, the polymer composite, which is part of the composition, is in a liquid state, however, quite often during the construction of the subgrade, it is not required to moisten the soil, especially clayey, because the moisture content of the soil is already close to the optimal one; accordingly, the quality decreases and the introduction of this polymer composite becomes more difficult when performing construction work.

The invention is aimed at improving the physical and mechanical characteristics of the composition for the device of functional layers of the subgrade, due to the use of a complex binder obtained by joint grinding of Portland cement clinker and additives for various functional purposes and the high-quality introduction of the polymer component into its composition.

This is achieved by the fact that the composition for the device of functional layers of the subgrade contains soil, binder and water. In this case, the soil is used in the form of loam with a plasticity number of not more than 12. The binder is used in the form of a complex binder obtained by joint grinding of Portland cement clinker, gypsum, anionic oligomer such as Melment F10 additives, wollastonite, active silica, with a specific surface area of 450 m ² / kg in a ratio of 17: 1: 0.2: 1.7: 0.1, respectively. The ratio of the components of the claimed composition is, mass. %:

loam 72-76 complex astringent 8-10 water rest.

The achievement of this technical result is due to the high homogeneity and density of the structure of the road-building material with a large number of new formations of calcium gyrosilicates in the form of nets and columnar elongated crystals due to the use of a complex binder and a greater strength of the contact zone between quartz particles of a loamy soil with hydration products of a complex binder and their interactions with clay particles.

Characteristics of raw materials:

1. Loam in accordance with GOST 25100 -2011 with a plasticity number of not more than 12;

2. Complex binder, in the form of mechanically activated powder mixture (MPS), consisting of:

- Portland cement clinker (K) in accordance with GOST 31108-2016,

- gypsum (G) in accordance with GOST 4013-2019,

- anionic oligomer like additive Melment F10 (D) in accordance with GOST 24211-2008,

- natural mineral wollastonite (B) with the chemical formula CaSiO ₃ ,

- active silica (AK) according to GOST 9428-73

(activated (grinding) in a ball mill to a specific surface area of 450 m ² / kg; mass ratio of materials: K: G: D: V: AK = 17: 1: 0.2: 1.7: 0.1)

3. Water in accordance with GOST 23732-2011.

The composition for the arrangement of functional layers of the subgrade of transport facilities was developed in accordance with the requirements of GOST R 55224-2012, GOST 23558-94 and GOST 30491-2012. The percentage composition of the composition was established empirically based on the results of determining the physical and mechanical characteristics of the material obtained (Table 1).

Table 1

Physical and mechanical characteristics of the compositions

No.
p / p composition, mass. % Compressive strength, MPa Ultimate tensile strength in bending, MPa Frost resistance, number of cycles Water saturation,
% Water saturation mode capillary complete capillary complete capillary complete capillary complete priming astringent hydrolysis lignin additive* water one loam 76 7 - - 17 7.14 6.25 0.91 0.81 fifteen fifteen 0.05 0.45 2 75 eight - - 17 7.65 6.68 1.09 0.93 twenty twenty 0.03 0.44 3 74 nine - - 17 8.02 7.08 1.25 1.07 25 25 0.03 0.42 four 73 10 - - 17 8.73 7.65 1.36 1.23 25 25 0.02 0.40 five 72 eleven - - 17 9.64 8.43 1.49 1.31 thirty thirty 0.01 0.40 6 ** sand from crushing screenings
82-85 8-6 5-2 0.4-0.8 5-7 - 2.80-4.00 - - - fifteen - -

* as an additive - polymer composite

** Prototype

To calculate the required amount of water in the composition, the maximum density and optimal humidity were determined in accordance with GOST 22733-2016. The loam was preliminarily dried to an air-dry state. Then, the prepared complex binder was introduced into the dried soil in the form of MPS in an amount of 7 to 10% with a step of 1%. MPS was prepared in advance in a ball mill by joint grinding of Portland cement clinker and additives for various functional purposes: gypsum, anionic oligomer like Melment F10 additive, natural mineral wollastonite, active silica. The composition was mixed manually and the soil was brought to the optimum moisture content. Samples were made from the resulting mixture in accordance with GOST 30491-2012. At the end of the hardening period, the composition was tested for strength, frost resistance, water saturation was determined at different modes of water saturation in accordance with GOST 30491-2012. The test results in comparison with the prototype data are presented in table 1.

An example of use is presented on the composition No. 4 (table 1):

They took 10 kg of silty loam with a maximum density of 1.76 g / cm ³ ; optimum humidity 17%. The loam was dried to a moisture content of 0%, and 1.37 kg of a complex binder in the form of MPS was introduced into the loam. MPS was prepared in advance in a ball mill by joint grinding of 1.16 kg of Portland cement clinker and additives for various functional purposes: gypsum - 0.07 kg, anionic oligomer like Melment F10 additive - 0.02 kg, natural mineral wollastonite - 0.11 kg, active silica - 0.01 kg. Mixed loam and complex binder and added 2.33 kg of water.

According to the requirements of GOST 30491-2012, samples of a cylindrical shape and beams in the form of prisms, three batches of each composition, were manufactured by pressing. The samples obtained hardened at an air temperature of 20 ± 2 ° C, humidity - not less than 95% within 28 days. After the end of the hardening period, the samples of the composition were tested for strength, frost resistance at full and capillary water saturation, and water saturation was also determined. Compressive strength: 8.73 MPa (capillary water saturation); 7.65 MPa (full water saturation). Flexural tensile strength: 1.36 MPa (capillary water saturation); 1.23 MPa (full water saturation). Frost resistance - 25 cycles (capillary and full water saturation). Water saturation 0.02% at capillary water saturation and 0.4% at full water saturation, respectively.

Comparative analysis with the prototype shows that the claimed composition for the device of functional layers of the roadbed of automobile and railways allows to obtain road-building material with high physical and mechanical properties. Its advantages are the small number of components, the stability of the introduction of the polymer component, because it is already part of the complex binder. It has the following characteristics: compressive strength - 6.68 - 8.73 MPa; tensile strength in bending - 0.93-1.36 MPa; frost resistance - 20 cycles at a complex binder content of 8% and 25 cycles at 9-10 wt. %, and the original soil 72-76 wt.%. According to the prototype, a material with a compressive strength of 2.80-4.00 MPa, a frost resistance grade of F20 was obtained. This difference from the prototype gives grounds to assert that the proposed technical solution meets the criterion of patentability of the invention "novelty".

Comparison of the proposed solution not only with the prototype, but also with other known technical solutions in this field of technology, did not confirm the presence in the latter of features that coincide with its distinctive features, or features that affect the achievement of the specified technical result. This made it possible to conclude that the invention meets the “inventive step” criterion.

Thus, the use of the proposed composition for the arrangement of functional layers of the subgrade will allow obtaining road-building material with the exact content of additives for various functional purposes, the introduction of which will not require a special construction technology; having a compressive strength of 6.68-8.73 MPa, a tensile bending strength of 0.93-1.36 MPa, and frost resistance of 25 cycles on loamy soils.

Claims (2)

Composition for the device of functional layers of the subgrade, containing soil, binder and water, characterized in that the soil is used in the form of loam with a plasticity number of not more than 12, the binder is used in the form of a complex binder obtained by joint grinding of Portland cement clinker, gypsum, anionic oligomer of the additive type Melment F10, wollastonite, active silica with a specific surface area of 450 m ² / kg with a material ratio of 17: 1: 0.2: 1.7: 0.1; with the following ratio of the components of the composition, wt. %: loam 72-76 complex astringent 8-10 water rest