RU2262493C1 - Dry pack mortar - Google Patents

Abstract

FIELD: construction engineering, in particular building materials base on composite lime-cement binder; mortar mix for finish plastering.

SUBSTANCE: claimed dry pack mortar contains hydrated lime as lime binder, and limestone sand containing 90-95 mass % of CaCO₃, having particle size from 0.001 to 0.8 mm as filler. Said filler represents waste from production of limestone grade, which is fed into backing step in calcium oxide manufacturing. Limestone sand according to grade size is used in the next ratio (mass %): grade 0.001-0.09 mm - 25.0-35.0; grade 0.09-0.8 mm - 65.0-75.0. More particularly, dry pack mortar contains (mass %): Portland cement 10.0-16.0; hydrated lime 3.0-7.0; said limestone sand 80.7-84.825; methylhydroxyethyl cellulose 0.02-0.04; hydroxypropyl starch 0.02-0.03; high molecular olefin sulfonate 0.02-0.03; bentonite hectorite-based sheet silicate 0.03-0.05; starch ester 0.005-0.01.

EFFECT: mortar mix for surface finishing of high quality with high adhesion, shrinkage and cracking resistance and low prime cost.

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Description

The invention relates to the field of construction, namely, building materials based on mixed lime-cement binders, and can be used for the preparation of mortars for the production of internal high-quality finishing plastering works.

In recent decades, dry mixes for the preparation of mortar have become widespread, allowing to bring construction technologies to a qualitatively higher level, namely, guaranteed consistently high quality of mixtures, imparting special properties to them through the use of a variety of chemical additives, reducing losses in production due to the small packing of dry mixtures, reducing transportation costs by reducing the volume of transportation, etc.

Dry building mixes containing lime-cement binder, sand as aggregate and organic additives (water-retaining, surface-active, adhesive, etc.) are widely known [Building materials. Ed. GI Gorchakova - M .: Higher school, 1982]. Before use, such a packaged mixture is shut with water.

In accordance with the standard (GOST 28013-98), mortar must comply with the main quality indicators: mobility, water holding capacity, delamination, average density, and after hardening must have compressive strength and bending, adhesion to the base.

Known dry building mixture, including cement, sand, lime binder, optionally containing a polymer binder, mica, titanium dioxide [A.S. USSR No. 391097, IPC С 04 В 28/02, 1973].

Also known is a construction composition, including Portland cement, lime dough, sodium chloride and iron minium [A.S. USSR No. 666146, IPC С 04 В 28/18, 1977].

But known mixtures have a weak water-holding ability and are short-lived, which limits the scope of their application.

Known dry building mixture containing Portland cement, fluff lime, quartz sand, mica, and additionally contains pigments [US Pat. RF №2122552, IPC С 04 В 28/04, 1998].

This building mixture, although it has a fairly high strength indicators, but is mainly intended for decorative painting (whitewashing) both inside and outside buildings.

Also known is a dry building mixture, including cement, sand, a lime binder, a polymer binder, a mineral filler, and chalk is used as a mineral filler with mass fractions of sodium chloride of not more than 1.5% and not more than 4.0% - sodium hydroxide production waste and brine cleaning, as a lime binder - lime-fluff - a waste of production of calcium carbide, burnt lime - a waste of production of calcium carbide and calcium hypochloride, as a polymeric binder - polyvinyl chloride - waste produced dstva polyvinyl chloride, and further ash CHP and methylcellulose [Pat. RU No. 2162827, IPC С 04 В 28 / 02.1999].

Also known is a dry building mixture containing, in wt.%: Cement 40-55, quartz sand 45-55, lime mixture for rocks 0.5-2.0, a plasticizer based on methyl cellulose and methoxypropyl cellulose 0.4-0.5. [Pat. RU No. 21119467, IPC С 04 В 28/02, 1996].

But the known dry mixes also do not have a sufficiently high water-holding ability and adhesion to the base.

Known dry building mixture containing, wt.%:

cement 17-40 sand 60-83 mechanically activated additive - superplasticizer C-3 0.5-2.0

[Pat. RU No. 2182137, IPC С 04 В 28/02].

The additive with a plasticizer may contain an anti-frost additive in an amount of from 0.5 to 5.0% by weight of cement.

The additive with a plasticizer may contain a sealing additive in an amount of from 0.5 to 5.0% by weight of cement.

The additive with a plasticizer may contain a dispersion reinforcing additive in an amount of from 0.5 to 5.0% by weight of cement.

The additive with a plasticizer may contain a coloring additive in an amount of from 0.5 to 5.0% by weight of cement.

The dry mixture may also contain a mixture of the above additives.

The presented dry mix is used for masonry and plastering.

The prepared mixture for plastering according to patent 2182137 has insufficient water retention and technological properties.

The closest technical solution (prototype) is a dry building mixture containing, wt.%:

lime cement binder 7-29 aggregate - silica in the form of sand 71-93 organic additives 0-0.2

[Pat. RU No. 2196752, IPC С 04 В 28/02, 2000].

The specified quartz sand fraction with a particle size of from 0 to 2.5 mm is used as a filler, the amount of a fraction from 0 to 0.5 mm being 10.0-28.85 wt.%, The fraction from 0.5 to 1.25 mm - 33.6-49.6 wt.%, fractions from 1.25 to 2.50 mm - 16.6-20.4 wt.%

Methyl cellulose-based water-retaining additives are used as organic additives.

To increase the water holding capacity, the sand is fractionated and introduced into the mixture so that the weight of the fraction 0.5-1.25 mm exceeds the total weight of the other sand fractions, but no more than three times.

The well-known dry mixture when mixed with water has insufficient plasticizing properties and, accordingly, the application processability, as well as insufficiently high water-holding ability to work in thin layers of plaster and fragility, and can be used to perform only ordinary plastering works.

The basis of the present invention is the task of creating a dry building mixture based on a lime-cement binder for internal plastering with the aim of high-quality surface finish with increased water retention and plasticizing properties, as well as high adhesive properties, with high resistance to shrinkage and cracking, as well as cost reduction, waste disposal.

The problem is solved in that hydrated lime is used as a lime binder, and limestone sand with a CaCO ₃ content _of 90-95 wt.% And a particle size of 0, 001 to 0.8 mm is used as a filler — waste of the production of limestone fraction supplied for firing in the production of calcium oxide, and limestone sand, depending on the size of the fraction taken in the following ratio, wt.%:

fraction 0, 001-0.09 mm 25.0-35.0 0.09-0.8 mm 65.0-75.0

as organic additives, the mixture additionally contains hydroxypropyl starch, high molecular weight olefin sulfonate, hectorite-based bentonite layered silicates, starch ether, and the dry mixture has the following composition, wt.%:

Portland cement 10.0-16.0 hydrated lime 3.0-7.0 limestone sand 80.7-84.825 organic supplement 0.175-0.260.

which use compounds, wt.%:

methyl hydroxyethyl cellulose 0.08-0.1 ethyl hydroxyethyl cellulose 0.02-0.04 hydroxypropyl starch 0.02-0.03 starch ether 0.005-0.01 high molecular weight olefin sulfonate 0.02-0.03 bentonite layered silicates 0.03-0.05

Portland cement 500 PC-DO according to GOST 10178-85 and hydrated lime according to GOST 9179-77 are used as binders.

The use of different fractions of limestone sand as a filler allows to increase the water-holding ability of the mortar and, accordingly, to obtain good mobility and viability of the mixture, which improves the manufacturability of the application on the base. The combination of fractions of limestone sand in the claimed ratio helps to achieve high adhesion of the stucco layer to the bases, allows to obtain a dense structure of the hardened mortar and to increase the durability and reliability of the building structure.

In addition, the use of a fine fraction of limestone, which is a waste of lime production, as a filler of dry construction mixtures allows you to utilize the excess limestone fractions and use natural resources in a qualified manner.

As a water-retaining additive in the claimed composition, a combination of 2 types of cellulose is used - methyl cellulose and ethyl hydroxyethyl cellulose, which allows the most complete hydration of clinker cement minerals during the hardening process of the plaster in a thin layer. To improve the ductility and wettability of the mixture, a pore former is used in the form of a high molecular weight olefin sulfonate, for example, the Hostapur OSB trademark in an amount of 0.01-0.04 wt.%. Hydroxypropyl starch, for example, Amiloteks 8100 brand, is used as an additive that improves the processability of applying plaster, namely, it reduces stickiness to the tool and improves resistance to slipping from the base, and starch ether, for example, commercial, is introduced to eliminate lumping and improve smoothness. Tilovis SE 7 brands. To compensate for the shrinkage phenomena accompanying the hardening of the cement binder and to improve crack resistance, an additive of modified bentonite clay in the form of bentonite layered minerals based on hectorite bearing the Bentone OS brand is introduced into the mixture.

Preparation of dry mortar is as follows.

First, fractionated limestone sand is prepared, the fractions of which are indicated above. For this, limestone waste in the production of lime - limestone crushed stone with a size of less than 30 mm is dried, crushed and sieved into the claimed fractions. Further, all components after weight dosing in the claimed ratio are fed to the mixer, in which a simple dry mix is prepared for use to produce a dry building mixture.

Tests of the dry building mixture are carried out according to the methods of GOST 5802-86. After mixing the mixture with water in a certain water-solid ratio, the water-holding ability is determined for the resulting mortar mixture, creep is determined by tests, the viability of the mixture is evaluated according to GOST 310.3-76, the shrinkage is determined according to GOST 11052-74, the adhesion to the base is determined according to GOST 28574-90.

Examples of the preparation of the compositions of the proposed dry building mix and its indicators are presented in the table.

As can be seen from the presented indicators, the claimed dry building mixture has a higher water retention capacity, and accordingly it has a higher viability. The proposed composition of the stucco mixture has a high resistance to slipping, the mixture is not prone to cracking and shrinkage phenomena, as well as higher adhesion to the base. These advantages allow us to carry out the claimed mixture of high-quality finishing plastering for processing walls in rooms with normal and high humidity both manually and mechanically, creating a surface ready for painting without additional technological methods.

№№ p.p Indicators Examples of formulations Prototype materials 1 2 3 materials 1 2 1. Composition, wt.% Portland cement 10.0 10.0 12.0 lime-cement hydrated lime 5,0 7.0 7.0 astringent 19.9 19.9 cellulose 0.08 0.08 0.1 organic additives 0.1 0.1 ethyl cellulose 0,03 0.02 0.02 sand fractions: hydroxypropyl starch 0.02 0.02 0,03 0-0.5 mm 10 twenty starch ether 0.007 0.005 0.01 0.5-1.25 mm 49.6 40 high molecules. olefin 0,025 0.02 0,03 1.25-2.5 mm 20,4 twenty bentonite 0.04 0,03 0.05 limestone sand total 84,798 82,825 80.76 with the ratio of fractions: 0.001-0.09 mm 31,0 35.0 25.0 0.09-0.8 mm 69.0 65.0 75.0 2. Water retention capacity,% 99,4 99.6 99.9 98.0 96.4 3. Cracked. not not not there is there is 4 Creep mm 0 0 0 3 3 5. R clutch, MPa 0.6 0.7 0.8 0.4 0.45 6. Viable. h 4 4 4 2 2 7. Shrinkage, mm / m 0.01 0.01 0.01 0.6 0.6

Claims (1)

Dry mortar for the preparation of mortar, including cement, lime binder, aggregate, organic additive, characterized in that hydrated lime is used as lime binder, and limestone sand with CaCO ₃ content _of 90-95 wt.% And size is used as aggregate particles from 0.001 to 0.8 mm - waste production of a fraction of limestone supplied for calcination in the production of calcium oxide, and limestone sand, depending on the size of the fraction taken in the following ratio, wt.%: Fraction 0.001-0.09 mm 25.0-35.0 0.09-0.8 mm 65.0-75.0 as an organic additive, in addition to methyl hydroxyethyl cellulose, it additionally contains ethyl hydroxyethyl cellulose, hydroxypropyl starch, high molecular weight olefin sulfonate, bentonite layered silicates based on hectorite, starch ether, and the dry mixture has the following composition, wt.%: Portland cement 10.0-16.0 Hydrated Lime 3.0-7.0 Limestone sand 80.7-84.825 Methyl hydroxyethyl cellulose 0.08-0.1 Ethyl hydroxyethyl cellulose 0.02-0.04 Hydroxypropyl Starch 0.02-0.03 High molecular weight olefin sulfonate 0.02-0.03 Bentonite Laminated Silicates 0.03-0.05 Starch ether 0.005-0.01