RU2652196C2 - Plaster gypsum dry construction mixture - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to construction materials industry, namely to building materials based on gypsum binders, and can be used in the manufacture of building mixtures for plastering walls and ceilings inside buildings for various purposes, including rooms with high humidity (more than 60%). Plaster gypsum dry construction mixture, which includes as components gypsum, lime building aerated calcium quicklime, thickener - ether starch, retarder hardening - citric acid, contains as a filler a mixture of ground claydite dust and blast-furnace granular slags, as the water-retaining component - methylhydroxypropylcellulose "Mecellose® FMC 7150 "with the following component ratio, in mass%: gypsum building – 46.85-54.64, building lime - 3-5, expanded clay dust, ground to a specific surface of at least 300 m²/ kg is 10-20, granulated blast furnace slag, ground to a specific surface of at least 500 m²/ kg is 20-40, methylhydroxypropylcellulose "Mecellose® FMC 7150 "- 0.1-0.3, citric acid – 0.039-0.041, starch ether - 0.011-0.02.

EFFECT: technical result is an increase in compressive and bending strength, adhesion strength to the substrate, water resistance of plaster dry mortar mixes, as well as a reduction in the cost of material due to waste production.

1 cl, 2 tbl

Description

The invention relates to the building materials industry, namely, building materials based on composite gypsum binders, and can be used in the production of building mixtures for plastering walls and ceilings inside buildings for various purposes, including rooms with high humidity (more than 60%).

Known gypsum mixture (Patent No. 2090533 (RU) C1, IPC С04В 28/14, С04В 22/08, С04В 24/04, publ. 09/20/1997), including semi-aquatic gypsum and the addition of alkaline effluents produced by caprolactam based on dicarboxylic acids ShchSPK, it additionally contains a multidental chelating ligand and trisodium phosphate in the following ratio, wt. %: semi-aquatic gypsum - 47-72; the addition of alkaline effluents for the production of caprolactam based on dicarboxylic acids ShchSPK - 0.2-0.8; multidental chelating ligand - 0.03-0.15; trisodium phosphate - 0.05-0.1; water is the rest.

The described composition has the following disadvantages: the stability of the composition due to its water-emulsion state is limited, in addition, in the description of the above composition there are no results of testing the samples for bending strength, adhesion to base, water resistance.

Known gypsum mixture (Patent No. 2237035 (RU) C1, IPC С04В 28/14, publ. 09/27/2004), containing in wt. %: gypsum - 90-92; perlite - 2.5-3.1; lime - 1.2-1.5; limestone flour - 4.0-5.0; hardening retarder - 0.035-0.045; ether cellulose - 0.13-0.16; redispersed powder - 0.018-0.03; air entraining additive - 0.008-0.015; starch ether - 0.09-0.1; technical sodium tripolyphosphate - 0.04-0.045.

The described composition has the following disadvantages: the resulting coating has low adhesion to the base, the use of plaster gypsum dry building mix is possible only in rooms with normal humidity conditions.

The closest analogue is the composition of gypsum gypsum dry mortar (Patent No. 2448923 (RU) C1, IPC С04В 28/14, С04В 111/27, publ. 04/27/2012), containing in wt. %: building gypsum - 75.95-88.44; lime - 3-5; expanded clay dust - 5-20; polyethylene oxide - 1.0-1.5; citric acid - 0.039-0.041; starch ether - 0.011-0.02.

The described composition has the following disadvantages: the resulting plaster coating has low compressive strength, adhesion to the base. In the description of the above composition there are no results of testing the samples for bending strength. Low water resistance can limit the life of the resulting plaster coatings in rooms with high humidity. The high consumption of building gypsum for plaster gypsum dry mortar significantly increases its cost.

The objectives of the invention is to increase the compressive and bending strength, the adhesion to the base, the water resistance of stucco gypsum dry building mixtures, as well as the cheapening of the material through the use of industrial waste.

The technical result is achieved by the fact that dry plaster gypsum building mixture, including building gypsum, quick building lime calcium, a thickener — starch ether, a hardening inhibitor — citric acid, contains as a filler a mixture of ground expanded clay dust and granulated blast furnace slag, in as a water-retaining component - methylhydroxypropyl cellulose "Mecellose® FMC 7150" in the following ratio of components, in wt. %:

- gypsum building - 46.85-54.64;

- Calcium building lime quicklime - 3-5;

- expanded clay dust, milled to a specific surface of at least 300 m ² / kg - 10-20;

- granulated blast furnace slag, milled to a specific surface of at least 500 m ² / kg - 20-40;

- methylhydroxypropyl cellulose "Mecellose® FMC 7150" - 0.1-0.3;

- citric acid - 0.039-0.041;

- starch ether - 0.011-0.02.

The following materials were used for the manufacture of dry plaster gypsum mortar:

- gypsum grade G-6 BP in accordance with GOST 125-79;

- building quicklime calcium quicklime of the first grade according to GOST 9179-77;

- expanded clay dust - waste from the production of expanded clay gravel from cyclones and dust filters of rotary kilns, crushed to a specific surface of at least 300 m ² / kg and containing in its mineral composition: undehydrated and dehydrated clay minerals (hydromica, montmorillonite), x-ray amorphous, quartz amorphous feldspars, anhydrite;

- granulated blast furnace slag - a by-product of the production of the Chelyabinsk Metallurgical Plant, dried to a residual moisture content of not more than 0.5% and ground to a specific surface of at least 500 m ² / kg, basicity modulus 1.0;

- citric acid according to GOST 908-2004;

- starch ether according to GOST 20370-74;

- methylhydroxypropyl cellulose “Mecellose® FMC 7150”, manufactured by Samsung Fine Chemicals (Korea), which is a water-soluble powder with a viscosity of 2% solution at 20 ° C according to Brookfeld - 25,000 mPa * s.

Preparation of stucco gypsum dry mortar is as follows.

Dried to a residual moisture content of not more than 0.5%, granulated blast furnace slag and expanded clay dust are subjected to separate grinding in a ball mill to specific surfaces, respectively, of at least 500 m ² / kg and at least 300 m ² / kg. Further, all components are loaded into the mixer and mixed to a homogeneous mass.

Testing of stucco gypsum dry mortar, mortar and mortar based on them was carried out in accordance with GOST 31377-2008, GOST 31376-2008.

The water resistance of the samples was determined by their softening coefficient equal to the ratio of compressive strengths of dry samples to water-saturated ones.

The compositions of stucco gypsum dry mortar are shown in table 1.

The results of mechanical tests in comparison with the prototype are shown in table 2.

Tests were also made of stucco gypsum dry mortar according to the prototype.

The data presented in table. 2 show that the developed plaster gypsum dry mortar with the introduction of mineral and chemical additives has higher properties compared to a similar dry mortar.

The introduction of complex mineral additives (crushed expanded clay dust, blast furnace granulated slag, building air quicklime lime) increases the compressive and bending strength, softening coefficient due to the increase in the amount of insoluble minerals formed in comparison with the prototype, the introduction of a complex of chemical additives, including Mecellose® FMC 7150, starch ether and citric acid, increases the adhesion to the base and provides long-term setting and viability of the mixture.

The resulting stucco gypsum dry mortar has improved physical and mechanical properties, and at the same time, the cost of the mixture is reduced by replacing much of the gypsum mortar with expanded clay dust and granular blast furnace slag, which is a non-hazardous production waste, compared to the analogue.

Claims (8)

Dry plaster gypsum mortar, including building gypsum, lime, thickener - starch ether, filler, water-retaining component, hardening retardant - citric acid, characterized in that it contains a mixture of ground expanded clay dust and granulated blast furnace slag as a filler, as a water-holding additive - methylhydroxypropyl cellulose "Mecellose® FMC 7150", in the following ratio, in wt. %: - gypsum building - 46.85-54.64; - building lime - 3-5; - expanded clay dust, milled to a specific surface of at least 300 m ² / kg - 10-20; - granulated blast furnace slag, milled to a specific surface of at least 500 m ² / kg - 20-40; - methylhydroxypropyl cellulose "Mecellose® FMC 7150" - 0.1-0.3; - citric acid - 0.039-0.041; - starch ether - 0.011-0.02.