RU2572432C1 - Additive for modification of gypsum binders, construction mortars and concretes on their basis - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: additive for modification of gypsum binders, construction mortars and concretes on their basis contains hydrate lime, a defoamer - hydrophobic ether, hyperplasticiser and dispenser - modified polyester carboxylate powder, at the following ratio of components, wt %: hydrate lime 58-70, defoamer 9-13, hyperplasticiser 3-7, dispenser 18-22.

EFFECT: increased strength parameters, softening coefficient, density, frost resistance, reduced water absorption, considerable reduction of energy inputs for grinding.

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Description

The invention relates to the field of building materials, namely, additives for gypsum binders, dry building mixtures, mortars and concrete based on them for the production of high-strength, mortar and composite gypsum concrete used in the construction of residential and public buildings.

A known additive for the modification of gypsum binders containing silica fume and superplasticizer C-3, obtained on the basis of sodium salts of condensation products of naphthalene sulfonic acid and formaldehyde, in the following ratio of components (% by weight): hemihydrous calcium sulfate - gypsum gypsum 78.4-81.6; lime 8-9; silica fume 10-12; superplasticizer C-3 0.4-0.6 (RF patent No. 2081076, IPC: C04B 11/00, C04B 111/20 from 06/10/1997).

The additive is made together with a gypsum binder, which increases the duration and volume of processing of the material. Moreover, the obtained gypsum binder has insufficient water resistance, strength, frost resistance, has a short setting time.

Known additive for the modification of gypsum binders, including C-3 superplasticizer, zeolite rock calcined at 800 ° C, and silicate brick fight, while the additive contains C-3 plasticizer in the form of dry powder in the following ratio of the components of the additive (% by weight): powder C-3 1.5-4.0; zeolite flour 12-14; silica brick fight 82-86 (see RF patent 2074137, IPC: С04В 11/00, С04В 111/20).

The additive is made separately from the gypsum binder, reducing the amount of processing, after which it is introduced in an amount of 5-15% by weight into a gypsum binder (100%) while mixing the dry mixture. This additive can increase the strength of gypsum products and save up to 15% gypsum binder, however, for the manufacture of the additive, significant energy is required for pre-firing the zeolite rock at 800 ° C for 8 hours and co-grinding the zeolite rock and fighting silicate brick with dry plasticizer powder C-3. The resulting binder has insufficient strength, frost resistance and short setting time of gypsum concrete.

Known additive for the modification of gypsum binders of the following composition in wt. %: hydraulic binder - Portland cement 15-25; mineral active component - pozzolanic flour 10-25; aqueous dispersion of a polyvinyl acetate polymer or divinyl styrene latex (A.V. Volzhensky et al. Mineral binders. - M.: Stroyizdat, 1979; p. 459-461).

The resulting gypsum binder has the best parameters for adhesive properties, durability, however, the preparation of a gypsum binder containing an aqueous dispersion is technologically difficult, in addition, the resulting gypsum binder has insufficient water separation, compressive strength, and frost resistance.

Known additive for the modification of gypsum binders, containing components: hydraulic binder - Portland cement of any kind; active finely dispersed siliceous materials - fly ash, ceramic dust, pumice dust, thermal power plant ash, glass breakage, waste products from brick and other ceramic products, fine quartz sand, silica fume, silica gel, etc. The specified materials and superplasticizer in a ratio of 1: (1 ... 2) :( 0.1 ... 0.25). Moreover, the maximum value of the specific surface is 500 m ² / kg, and this is not always sufficient to improve the physical and mechanical properties of gypsum binders, mortars and concrete based on them (Yu.M. Bazhenov, V.F. Korovyakov, G.A. Denisov. Technology of dry building mixtures. - M.: Iz-in Association of Building Universities, 2003, pp. 2-25, 48).

Known composite high-strength gypsum material made from a composition comprising a gypsum binder, calcium hydroxide, potassium polymethylsiliconate, sodium polycarboxylate, isonicotinic acid hydrazide, sodium tripolyphosphate, water and a silica filler.

A method of obtaining a composite high-strength gypsum material includes the separate preparation of a mixture of aqueous solutions of calcium hydroxide and potassium polymethylsiliconate and a mixture of aqueous solutions of sodium polycarboxylate, isonicotinic acid hydroxide and sodium tripolyphosphate, the subsequent combination of the resulting mixtures with stirring and the introduction into the combined mixture of gypsum binder with stirring to obtain a uniform while a silica-containing filler is added to the resulting suspension and their final mixing until a homogeneous composition is obtained (patent RU No. 2358931, С04В 11/28 from 02.27.2009).

A composite material is known, including calcium hydroxide, a gypsum binder, a plasticizer, setting retarder and crushed stone, characterized in that a gypsum binder is used as a gypsum binder or a mixture of building and high strength gypsum binders, natural shungite crushed stone with a particle size of 5-20 mm is used as crushed stone. , as a plasticizer, sodium polycarboxylate, and as a retarder of setting amidox in the following ratio of components, wt. %: the specified gypsum binder 18-38, calcium hydroxide 0.5-1.0, the specified schungite crushed stone 51-74, sodium polycarboxylate 0.5-0.8, amidox 0.2-0.5, the rest is water.

A method of obtaining a composite material involves mixing said schungite crushed stone with a solution of sodium polycarboxylate and amidox in water, followed by adding powdered calcium hydroxide and said gypsum binder to the resulting mass with stirring to obtain a uniformly coated suspension of schungite crushed stone (RU No. 2405749, class C04B 28/14 from 12/10/2010).

A complex multifunctional concrete modifier is known, including a mineral component, calcium hydroxide and a plasticizing additive, characterized in that it contains amorphous silica or quartz sand as a mineral component, a plasticizing additive selected from the group comprising sodium polycarboxylate, sodium salt of sulfonated naphthalene formaldehyde resin, sodium a salt of sulfonated melamine formaldehyde resin, and optionally sodium tripolyphosphate.

A complex modifier of concrete of multifunctional action, including an aqueous solution of a plasticizing additive, characterized in that it contains a plasticizing additive selected from the group including technical sodium lignosulfonates, sodium salt of sulfonated naphthalene formaldehyde resin, sodium salt of sulfonated melamine formaldehyde resin, sodium polycarboxylate and sodium triphosphate aqueous solution potassium polymethylsiliconate and water. A complex modifier of concrete of multifunctional action, including an aqueous solution of a plasticizing additive, characterized in that it contains a plasticizing additive selected from the group including technical sodium lignosulfonates, sodium salt of sulfonated naphthalene formaldehyde resin, sodium salt of sulfonated melamine formaldehyde resin, sodium polycarboxylate and sodium triphosphate aqueous solution , potassium polymethylsiliconate and water (RU No. 2361833, class C04B 22/00 of 07/27/2010).

Known additive for the modification of gypsum binders, mortars and concrete based on them, including% by weight: hydraulic binder 50-90; active mineral component 10-45, plasticizing additive 0.1-2.0, regulator of setting and hardening periods 0.001-1.0; stabilizer 0.001-5. Moreover, as a hydraulic binder, the additive contains Portland cement of any kind, white cement or a mixture of them in any proportion, as an active mineral component - fly ash, ash of rice or buckwheat husks, ashes and slag of thermal power plants, ceramic dust, brick waste, other ceramic production, aluminum compounds, fine quartz sand, silica fume, pumice, glass break, silica gel, tuff, diatomite, white soot, aerosil or any mixture thereof in any proportion, as a plasticizing additive - superplas a tifier containing compounds based on sulfonated melamine formaldehyde compounds and / or complexes based on them, compounds based on sulfonated naphthalene formaldehyde compounds or their complexes based on them, compounds based on modified lignosulfonates, or compounds based on water-soluble carboxylate polymers, or a mixture thereof in any proportion , as regulators of setting time and hardening - a gypsum hardening moderator, as a stabilizer - water-soluble cellulose ether. In this case, one of the following components or semi-aquatic gypsum or anhydrite mixed in any proportion is used as gypsum binders, the dosage of the additive is carried out in an amount of 10-40% of their mass, and its specific surface is 550-7000 m ² / kg (RF patent No. 2260572, IPC: С04В 11/00, published on September 20, 2005).

The disadvantages of the known method and composition of the additive are:

- a large amount of additive by weight of processing due to the inclusion of Portland cement (up to 90%) and the active mineral component up to 45%,

- a large dosage of the additive (10-40% by weight);

- insufficient strength and water resistance obtained with its help of gypsum binders, dry building mixtures, mortars and gypsum concrete below 20.0 MPa with a water-gypsum ratio of 0.22-0.3.

Known adopted for the prototype, an additive for gypsum binders, dry building mixtures, mortars and concrete based on them, containing powdered calcium hydroxide, potassium hydroxide, plasticizer-sodium polycarboxylate, antifoam AXILAT, water-repellent - polymethyl sodium silicate and retarder setting and hardening - gluconate sodium in the following ratio, wt.%: calcium hydroxide 52.0-70.8, potassium hydroxide 1.0-4.6, sodium polycarboxylate 13.5-18.3, AXILAT 4.1-7.0, sodium polymethylsiliconate 6.6-12.0, sodium gluconate 4.0-6.1 (see RF patent No. 2408551, IPC С04В 11 / 00 from 01/10/2011).

In the mixer, 6.8 kg of calcium hydroxide (70.0%) is mixed with 0.1 kg of potassium hydroxide (1.0%); 1.5 kg of powdered sodium polycarboxylate (15.5%); 0.5 kg of calcium polymethylsiliconate (5.1%); 0.4 kg of powder defoamer - Axilat (4.1%) and 0.4 kg of binder retarder - sodium gluconate (4.1%), the resulting mixture is subjected to grinding in a high-speed grinder (disintegrator) to a particle fineness of less than 50 microns. The resulting mixture, which is an additive for a gypsum binder, is used for the production of dry building mixtures. For experimental verification of the resulting composition of the additive, it is mixed in an amount of 0.012 kg in the presence of 0.024 kg of water with 0.8 kg of building gypsum binder grade G 5, the consumption of the additive is 1.5% relative to the gypsum binder, W / G ratio 0.295. The produced additive has: energy-intensive grinding process, low productivity, a large number of components.

The objective of the invention is to obtain additives gypsum modifier (MG-4) with a significant reduction in energy consumption for its manufacture, able to several times increase the physico-chemical properties of gypsum binders at low dosages of the additive.

A fundamental factor in the successful manufacture of the MG-4 additive is the creation of favorable activation conditions (grinding with low grinding resistance) of the above components.

The technical task of this invention is provided by the fact that the additive for the modification of gypsum binders, mortars and concrete based on them contains hydrated lime, antifoam-hydrophobic ether, hyperplasticizer and dispersant - modified polyester carboxylate powder, in the following ratio, wt.%:

Hydrated lime 58-70 Antifoam agent 9-13 Hyperplasticizer 3-7 Dispersant 18-22

The method of producing MG-4 consists in the activation of all components of the additive in a centrifugal mill, contributes to better grinding, with a significant reduction in energy costs for manufacturing, which can several times increase the physicochemical properties of gypsum binders at low dosages of the additive.

The ionized radiation gas is fed into the grinding chamber, as a result of which grinding occurs with less resistance to grinding, obtaining a modifying additive that significantly improves the physicomechanical properties of gypsum binders, dry mixes based on them, mortars and composite materials (concrete) based on them, as well as reduction of energy consumption for obtaining a finely ground additive with a specific surface of less than 700 m ² / kg and an increase in the economic benefits of using the additive. The objective of the invention is to obtain additives gypsum modifier (MG-4) with a significant reduction in energy consumption for its manufacture, able to several times increase the physico-chemical properties of gypsum binders at low dosages of the additive.

The fundamental factor in the successful manufacture of the MG-4 additive is the creation of favorable activation conditions (grinding with low grinding resistance) of the above components. The manufacture of additives takes place in three stages:

1. Joint mixing of all components in a horizontal single-shaft mixer of forced mixing of cyclic action.

2. Activation of all components of the additive in a centrifugal mill with the supply of ionized radiation gas to the grinding chamber.

3. Packing in four-layer paper bags.

For the visual effectiveness of the additive, Table 1 below shows tests of gypsum binders of α-, β-modifications with the additive (MG-4) in three forms of processing.

An example of the implementation of "hyperplasticizer" and "modified polyester carboxylate powder."

The dispersant, a modified polyester carboxylate powder, is a comb-shaped copolymer with an average molecular weight of (15-50) × 10 ³ units, containing from 50 to 96.9 mol% of structural units of the general formula I: where R ¹ = H or CH3; X = -OMA, -NH- (CmH2mO) nR ² ; Y = H, COX; M = H, modified by a mono- or divalent metal cation.

Hyperplasticizer - Melflux 5581 from BASF Constraction Polymers (Trostberg, Germany).

The technical result of the proposed technical solution is to simplify the production technology, reduce energy consumption when grinding crystalline powders having a weak crystal lattice, increase the strength and water resistance of the obtained gypsum materials, and make it possible to control the quality of dry building mixtures, mortars and concrete based on them.

The objective of the invention is to obtain additives gypsum modifier (MG-4) with a significant reduction in energy consumption for its manufacture, able to several times increase the physico-chemical properties of gypsum binders at low dosages of the additive.

The fundamental factor in the successful manufacture of the MG-4 additive is the creation of favorable activation conditions (grinding with low grinding resistance) of the above components.

Claims (1)

An additive for the modification of gypsum binders, mortars and concrete based on them, characterized in that it contains hydrated lime, antifoam - hydrophobic ether, hyperplasticizer and dispersant - modified polyester carboxylate powder, in the following ratio, wt.%:
Hydrated lime 58-70 Antifoam agent 9-13 Hyperplasticizer 3-7 Dispersant 18-22