RU2786931C1 - Dry construction mix - Google Patents

Abstract

FIELD: production of building materials.

SUBSTANCE: invention relates to the production of building materials and, in particular, to dry building mixes used for the manufacture of plaster mortars, and can be used to create finishing coatings.

EFFECT: invention provides necessary adhesion with an increase in the physical and mechanical properties and performance characteristics of coatings based on dry construction mix, as well as reducing the cost of final products while improving the environmental situation through the use of man-made waste in the mixture. The dry construction mix contains Portland cement, a structure-forming and reinforcing additive, a superplasticizer and a fine filler. Portland cement TSEM II/A-Sh 32.5B and a polycarboxylate ether-based superplasticizer are used, basalt fiber production waste with a length of 7-15 mm, a width of 3-5 mm, a thickness of 0.13 ±0.03 mm is used as a structure–forming and reinforcing additive, and a sand fraction of concrete scrap with a grain size of 0.16-0.325 mm is used as a fine filler, with the following the content of components in wt.%: Portland cement CEM II/A-W 32.5B 13.8-18.5; superplasticizer based on polycarboxylate ether 0.7-1.1; basalt fiber waste 4.4-5.8; sand fraction of concrete scrap screening 76.4-79.3.

1 cl, 3 tbl

Description

The invention relates to the production of building materials and, in particular, to dry mortars used for the manufacture of plaster mortars, and can be used to create finishing coatings.

Known dry mortar with super-penetrating concrete ability and high adhesion, based on general construction nanocement, including sand for construction work of a fraction of 0.63 mm, calcium chloride, sodium nitrate and sodium carbonate, additionally contains potassium sulfate and general construction nanocement as a binder, with the following ratio of components, wt. %: specified sand 50.3-53.9, general construction nanocement 40-42, potassium sulfate 2.5-3.0, sodium carbonate 2.0-2.5, sodium nitrate 1.5-2.0, calcium chloride 0.1-0.2 (RF patent No. 2576760, IPC C04B 28/00, C82B 3/00, C04B 41/65, 2015).

The disadvantage of the prototype is the low impact strength of the concrete obtained by hardening the mixture, which makes it difficult to use as a repair composition for building envelopes.

Known dry building mixture, including Portland cement, filler and plasticizing additive, characterized in that it uses quartz sand with a particle size modulus of 0.95-1.05 as a filler, and ferruginous hydrated cake is used as a plasticizing additive - a non-ferrous waste metallurgy, crushed before passing through a sieve with holes of 0.2 mm, in the following ratio, wt. hours: Portland cement - 0.75-1; specified quartz sand - 2.9-3.0; the specified ferruginous hydrated cake is -0.3-0.55 (RF patent No. 2520652, IPC C04B 28/04, 2014).

The disadvantage of this mixture is the low mobility, ductility and water-holding capacity of the mixture, as well as the high cost of the finished building mixture.

As the closest analogue (prototype), a dry building mixture was chosen, which includes a mineral binder, natural quartz sand and crushed limestone screening, a complex additive UP-4 and waste from the production of polypropylene fibers, in the following ratio, wt. %: Portland cement - 19.65-18.7, natural quartz sand with a particle size modulus of 1.82 - 43.0-37.0, screening of crushed limestone fraction 0-5 mm - 37.0-44.0, complex additive UP-4 - 0.15-0.1, production waste of polypropylene fibers - 0.2 (RF patent No. 2528774, IPC C04B 28/04, 2014).

The disadvantage of this mixture is the insufficient strength of the finishing coating made from the specified mixture, in tension and compression.

The task to be solved by the claimed invention is to improve the physical and mechanical properties and performance characteristics of coatings based on dry mortar.

The technical result, which manifests itself in solving the problem, is expressed in providing the necessary adhesion with an increase in the physical and mechanical properties and performance characteristics of coatings based on a dry building mixture, as well as in reducing the cost of the final product while improving the environmental situation, due to the use of man-made waste.

The problem is solved by the fact that a dry mortar containing Portland cement, a structure-forming-reinforcing additive, a superplasticizer and a fine aggregate is characterized in that Portland cement CEM II / A-Sh 32.5B is used, waste from the production of basalt fiber is used as a structure-forming-reinforcing additive. 7-15 mm long, 3-5 mm wide, 0.13 ± 0.03 mm thick, superplasticizer based on polycarboxylate ether, and as a fine aggregate - sand fraction of concrete scrap screening with a particle size of 0.16-0.325 mm, with the following content components in wt. %:

Portland cement CEM II / A-Sh 32.5B - 13.8-18.5;

superplasticizer based on polycarboxylate ether - 0.7-1.1;

basalt fiber production waste - 4.4-5.8;

sand fraction of concrete scrap screening - 76.4-79.3.

A comparative analysis of the essential features of the proposed technical solution with the essential features of the prototype and analogues indicates its compliance with the criterion of "novelty".

In this case, the distinctive features of the claims solve the following functional tasks.

The sign "portland cement CEM II / A-Sh 32.5B is used" provides increased strength of the dry building mixture after three days of hardening.

The feature “using a superplasticizer based on polycarboxylate ether” describes the type of superplasticizer used, which makes it possible to increase the workability of a dry building mix while reducing the water-cement ratio, which has a positive effect on the structure formation of concrete while eliminating the process of microcracking.

The feature “basalt fiber production waste 7–15 mm long, 3–5 mm wide, 0.13 ± 0.03 mm thick” is used as a structure-forming and reinforcing additive makes it possible to create a more durable composite at the micro and macro levels, which has a positive effect on a whole range of physical and mechanical properties, including compressive, tensile and bending strength.

The sign "as a fine aggregate, a sandy fraction of screening of concrete scrap with a particle size of 0.16-0.325 mm is used" contributes to an increase in environmental friendliness due to the disposal of demolition waste with the simultaneous use of previously unreacted concrete cement particles.

Signs "with the following content of components in wt. %:

Portland cement CEM II / A-Sh 32.5B - 13.8-18.5;

superplasticizer based on polycarboxylate ether - 0.7-1.1;

basalt fiber production waste - 4.4-5.8;

sand fraction of concrete scrap screening - 76.4-79.3 "describe the optimal ratio of components.

Details of the components used are shown in Table 1.

Table 1

Concrete Mix Components

Component Regulatory document Source Example Specifications Appointment as a part of concrete mix Portland cement II/А-Ш 32.5B GOST 31108-2003 GOST 31108-2003 Strength class 32.5 astringent Superplasticizer based on polycarboxylate ether GOST 24211-2008 GOST 24211-2008 Water reducing capacity 75-80% plasticizing chemical modifier Basalt fiber production waste GOST 30459-2008 Provided by BSTU. V.G. Shukhov Length 7-15 mm,
width 3-5 mm
thickness 0.13±0.03 mm Structure-forming reinforcing additive Sand fraction of screening of concrete scrap GOST 8736-2014 Concrete scrap Fineness 0.16-0.325 mm fine aggregate

The inventive dry mixture is prepared on standard equipment according to standard technology in several stages.

1. Preliminary processing of waste from the production of basalt fiber using a milling-roller of combined action to obtain particles 7-15 mm long, 3-5 mm wide, 0.13 ± 0.03 mm thick.

2. Mix all other components in a paddle mixer for 5-7 minutes until smooth.

3. Basalt fiber production waste prepared according to item 1 is introduced into the mixer in small portions for uniform distribution throughout the volume of the mixture.

4. After intensive and thorough mixing, the finished mixture from the mixer is fed into the finished product hopper, from where the material is packed into bags using a filling machine.

To ensure a stable composition of the mixture, it is necessary to constantly monitor the moisture content of the raw materials and adjust the composition before dosing.

Examples of concrete mix compositions are shown in Table 2.

table 2

Compositions of concrete mix

Component Content, wt. % Composition 0 Composition 1 Composition 2 Composition 3 Composition 4 Composition 5 Portland cement II/А-Ш 32.5B 18.5 18.5 18.3 16.1 13.8 13.8 Superplasticizer based on polycarboxylate ether 0.7 0.7 0.8 0.9 1.1 1.1 Basalt fiber production waste 0 4.4 4.4 4.5 5.8 10 Sand fraction of concrete scrap screening, mm:
0.16 - - - - 79.3 83.5 0.20 80.8 76.4 - - - 0.30 - 76.5 - - 0.325 - - 78.5 - Total: 100 100 100 100 100 100

The performance characteristics of the developed dry building mixtures are shown in Table 3.

Table 3

Properties of the concrete mix

Characteristic Prototype Composition 0 Composition 1 Composition 2 Composition 3 Composition 4 Composition 5 Water-holding capacity, %, 95 94.2 96.2 95.9 95.6 95.3 94.3 Strength of adhesion to the base, MPa 0.4 0.5 1.4 1.1 0.8 0.5 0.5 Water absorption with capillary suction, kg / m ² 0.40 0.42 0.22 0.26 0.30 0.33 0.43 Vapor permeability coefficient, mg/m∙h∙Pa 0.020 0.018 0.035 0.031 0.028 0.024 0.020 Presence of cracks due to shrinkage eat eat No No No No eat Water absorption of hardened solutions, % by weight fifteen 15.3 9.8 10.6 11.5 12.5 15.2 Compressive strength, MPa 10.00 12.36 36.21 33.24 29.55 24.82 14.32 Bending strength, MPa 1.26 2.32 11.23 9.21 7.32 5.27 3.65 Frost resistance, cycles fifty fifty 60 60 60 60 fifty Frost resistance of the contact zone, cycles fifty fifty 55 55 55 55 fifty Coating weather resistance, cycles 100 100 150 150 150 150 100

Based on the data in Table 3, we can conclude that the claimed composition of the dry mortar has the following advantages over the known ones:

- increased physical and mechanical properties and performance characteristics several times;

- the consumption of Portland cement was reduced due to its waste from the production of basalt fiber and screening of concrete scrap;

- increased environmental friendliness due to reduced consumption of Portland cement with simultaneous disposal of man-made waste.

The boundary conditions for increased and reduced content of components (compositions 0 and 5) show the optimal compositions (compositions 1-4), which provide the necessary set of maximum values of physical and mechanical properties and performance characteristics of dry building mixes.

Example (table. 2, composition 1)

We mix 18.5 kg of Portland cement II / A-Sh 32.5B), 0.7 kg of superplasticizer based on polycarboxylate ether and 76.4 kg of sandy fraction of screening of concrete scrap with a particle size of 0.20 mm in a paddle rotary mixer for 5-7 minutes to homogeneity.

We pre-process waste from the production of basalt fiber using a milling-roller of combined action to obtain particles 7-15 mm long, 3-5 mm wide, 0.13 ± 0.03 mm thick and introduce into the mixer in small portions for uniform distribution throughout the volume mixtures in the amount of 4.4 kg.

After intensive and thorough mixing, the finished mixture is fed from the mixer into the finished product hopper, from where the material is packed into bags using a filling machine.

To ensure a stable composition of the mixture, it is necessary to constantly monitor the moisture content of the raw materials and adjust the composition before dosing.

Claims (2)

Dry mortar containing Portland cement, a structure-forming reinforcing additive, a superplasticizer and a fine aggregate, characterized in that Portland cement CEM II / A-Sh 32.5B and a superplasticizer based on polycarboxylate ether are used, waste from the production of basalt fiber is used as a structure-forming reinforcing additive 7-15 mm long, 3-5 mm wide, 0.13 ± 0.03 mm thick, and as a fine aggregate - a sandy fraction of concrete scrap screening with a particle size of 0.16-0.325 mm with the following content of components in wt.%: Portland cement CEM II/А-Ш 32.5B 13.8-18.5 based superplasticizer polycarboxylate ether 0.7-1.1 basalt fiber production waste 4.4-5.8 sand fraction of screening of concrete scrap 76.4-79.3