RU2364576C1 - Complex modifying additive for construction mortar and method for production of construction mortar - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention is related to compositions of additives for construction mortars and making of construction mortars, which may be used as plastering mortars, putty mixes, glues for tiles, ready construction mortars for erection of monolithic structures, construction mass for leveling of floors, etc. Complex modifying additive for construction mortar contains the following components, wt parts: mineral component - 100, water-retaining active ingredient - cellulose ether - 0.1-1.0, water - 8-50. Additive contains mineral filler and/or filler as mineral components, and also at least one additional active ingredient from group: redispersed polymer powders, water soluble plasticising, air entraining, waterproofing, biocide, accelerating and slowing hardening of construction mortar, pigmenting additives. Construction mortar is produced by mixing of binder with specified additive in the following ratio, wt parts: modifying additive - 100, binder - 10-45. When mixing binder with additive, water may be introduced additionally.

EFFECT: higher vitality, improved mobility and convenience of construction mortar laying.

5 cl, 1 tbl, 10 ex

Description

The invention relates to the building materials industry, namely, the compositions of complex modifying additives for mortars and the manufacture of mortars, which can be used as plaster mortars, putty mixtures, adhesives for tiles, ready-made mortars for the construction of monolithic structures, building mass for floor leveling etc.

To regulate the technological and construction-technical properties of mortars, various modifying additives are used. It is preferable to use complex additives comprising several components, which allows to obtain mortars with a complex of required properties. The most important property of mortar is workability, which is determined by the mobility (fluidity) of the mortar. With increasing water content, the mobility of the mortar increases, however, the amount of water introduced into the composition of the mortar is limited by the holding capacity of the cement. Retention of moisture in the solution helps to reduce the degree of return of water by the hardening mortar to the environment and to the base with which the solution is in contact. Therefore, water-holding additives, in particular cellulose ethers, which have good water-holding properties (SU 881045, C04B 13/14, 1981; SU 920025, C04B 13/24, 1982; SU 1070129, C04B 15/02, are widely used for the preparation of mortars. 1984; SU 1689322, C04B 11/00, 1991; RU 2233255, C04B 28/30, 2004).

Known dry complex modifying additive (RU 2204540, C04B 28/00, 2003), containing, wt.%:

silica fume - 0.1-30.0

plasticizer - 0.5-3.0

dolomite or limestone flour - 40.0-92.0

water-soluble cellulose ether - 0.1-3.0

redispersion powder in the form of copolymers of polyvinyl acetate or acrylate - 0.3-24.0,

and included in the composition of the dry mortar mixture, containing, wt.%: binder 25-35, aggregate 55-74, complex modifying additive 1.0-10.0. The aggregate includes, wt.%: Silica sand 85.0-99.9, silica fume 0.10-15.0. Cementing agents of various grades, complex cement-lime and lime-cement binders can be a binder. The mixture is intended for laying tiles.

The preparation of this dry mortar mixture is as follows. The filler and the modifying additive are prepared separately, their components are metered in accordance with the recipe, loaded into the mixer and mixed for 1-10 minutes. Then, the binder and the prepared aggregate and the modifying additive are dosed in accordance with the recipe. The resulting dry mixture is Packed in standard bags and sent to the consumer.

To use this mixture, a working mortar is prepared from it as follows. A portion of the mixture is poured into a container, water is added to a working consistency, mixed and incubated for 5-15 minutes. Then, a layer of the prepared solution is applied to the prepared surface or to the material to be laid and the material is laid. The dry mortar mixture provides peel strength of up to 1.2 MPa, tensile strength of adhesive joints in compression - up to 18 MPa.

The disadvantage of dry mortar mixtures is the limited shelf life (0.5 years) due to the presence of cement in them, which quickly loses its activity, absorbing moisture from the air (after 3 months, the mixtures lose up to 20% strength). Therefore, for the preparation of mixtures, only dry components are used and the prepared mixtures are stored in dry conditions. This requires the presence of special drying equipment at dry mix factories or the delivery of dry components from specialized enterprises using special vehicles. All this leads to a significant increase in the cost of production. In addition, for such mixtures containing all the components necessary for the preparation of a mortar, a clear separation by field of application is characteristic.

When water mixes dry building mixtures, the process of hydration and setting of cement takes place before the complete dissolution or dispersion of the dry components of the modifying additive occurs. This problem is especially relevant for cellulose ethers, many of which dissolve (swell) with the formation of water-retaining gels for several hours (up to 1 day). Therefore, it is not possible to achieve a significant improvement in the mobility and workability of a mortar based on dry mortar containing cellulose ethers. The viability of such a mortar is 1-2 hours, which does not allow transporting it over long distances from the place of manufacture.

The closest in technical essence to the proposed is a dry complex modifying additive, including, wt.%: Mineral filler 50-95, cellulose ether 5-50 as an additional active ingredient (RU 2211205, C04B 40/00, C04B 28/02, 2003 ) At the same time, a filler from the group of calcite, barite, limestone flour, marble flour, dolomite flour, pulverized quartz, various types of cement, gypsum, corundum, amorphous silica is used as a mineral filler. The additive may additionally contain other active ingredients: redispersion powders of copolymers and homopolymers of vinyl acetate, acrylate and butadiene styrene, water-soluble plasticizing, water-reducing, air-absorbing, water-repellent, pigmenting additives in dry form.

The additive is obtained by mixing a mineral filler, cellulose ether and, if necessary, other additional active ingredients at a certain ratio, followed by active mixing in turbulent flows. The production of such a dry modifying additive is an independent production, and the additive is a commercial product. Consumers can use it for the preparation of mortars in a well-known way by mixing with sand, cement and water. Compared to the above, this additive has a more universal field of application, since using it, depending on the type of cement added, it is possible to obtain tile glue, plaster for various surfaces, building mass, etc.

However, the process of preparing a dry complex modifying additive requires the use of dry components, which is associated with additional energy costs. Cellulose ethers are in the modifying additive in dry form, therefore mortars prepared using such an additive have, as in the previous case, insufficient mobility, workability and viability.

Well-known methods for producing mortars by mixing cement with filler (sand) and water.

The closest in technical essence to the proposed one is a method of obtaining a mortar by mixing cement with sand, a dry complex modifying additive and water (RU 2211205, C04B 40/00, C04B 28/02, 2003).

The disadvantage of this method is to obtain a mortar with insufficient mobility, workability and viability due to the introduction into the solution of the modifying additive in dry form.

The problem to which the invention is directed, is to increase the efficiency of production and use of complex modifying additives.

The technical result that can be obtained using the proposed invention is to reduce the cost of additives, increase vitality, improve mobility and workability of mortar.

To achieve this result, a complex modifying additive for mortar containing a mineral component and cellulose ether as a water-retaining active ingredient is proposed, characterized in that it additionally contains water in the following ratio of components, parts by weight: mineral component - 100, cellulose ether - 0.1-1.0, water - 8-50.

As a mineral component, the additive contains a mineral aggregate and / or filler. The additive may also contain at least one additional active ingredient selected from the group consisting of redispersible polymer powders, as well as water-soluble plasticizing, air-entraining, water-repellent, biocidal, accelerating and delaying the setting mortar pigmenting additives.

The introduction of water into the composition of the modifying additive allows the use of its components with their natural moisture content, without resorting to additional drying.

To achieve this result, a method for producing a mortar by mixing a binder with a complex modifying additive is also proposed, characterized in that the proposed complex modifying additive is used in the following ratio of mortar components, parts by weight: modifying additive - 100, binder - 10-45.

Since the proposed additive already contains water, when mixing the binder with this additive, you can either not introduce water or add it in such an amount as to obtain the desired consistency of the solution.

Upon receipt of the complex modifying additive, fillers (for example, dolomite flour, limestone flour, marble flour, pulverized silica), aggregates (for example, silica sand) or various mixtures thereof are used as a mineral component. The cellulose ethers used may be, for example, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, or mixtures thereof.

To modify the technological and construction-technical properties of a mortar, you can also use commonly used additional active ingredients in amounts effective for each ingredient:

water-soluble plasticizing additives - lignosulfonate, superplasticizer C-3, melamine - and naphthalene formaldehyde oligomers, etc .;

air-entraining additives - mixtures of alkylarylsulfonates, organic sulfo acids and their salts, etc .;

water-repellent additives - calcium, magnesium, zinc stearates, sodium oleate, etc .;

biocidal additives - Caton LXE based on 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one, Nuosept 95 based on substituted oxazolidine, etc .;

additives that regulate the setting time of the mortar - sodium aluminate, calcium formate, citric acid, oxalic acid, malonic acid, etc.

In addition to the aforementioned additional ingredients, the modifying additive may also contain others, for example, antifoam agents, anti-shrink, anti-frost, increasing strength and adhesion, etc.

To prepare the mortar, depending on its purpose, you can use various types of binders - Portland cement of various grades, slag-Portland cement, pozzolanic cement, gypsum, etc.

The invention is illustrated by the following examples.

Examples 1-9. The complex modifying additive according to the invention is prepared as follows. The components of the modifying additive are mineral fillers and / or fillers, cellulose ethers, water and, if necessary, additional active ingredients are dosed by weight in accordance with the recipe and loaded into the mixer. By turning on the mixer motor, the components are mixed for 8-15 minutes. The resulting mixture has sufficient fluidity, it is Packed in a suitable container and delivered to the consumer after exposure for a period of time from several hours to 1 day (depending on the properties of the raw materials used).

When preparing the mortar, a portion of the modifying additive is mixed with a binder and, if necessary, with water in the mixer, the resulting mortar has high mobility and workability. It is used at the place of preparation or transported to the consumer. The viability of the resulting solution is 3-4 hours, so that the solution can be transported over considerable distances.

The compositions of modifying additives, mortars based on them and the test results of the latter are shown in the table.

Example 10 (comparative). A complex modifying additive is prepared analogously to examples 1-9. The additive composition corresponds to example 3 with the difference that carboxymethyl cellulose is administered in an amount of 0.05 parts by weight. The resulting mixture is Packed and delivered to the consumer after exposure for 12 hours. When preparing the mortar, a portion of the modifying additive is mixed with a binder and, if necessary, with water in the mixer. It is used at the place of preparation, since the viability of the resulting solution is 1-1.5 hours.

Indicator The compositions of complex modifying additives and mortars (parts by weight), the properties of the solutions used to obtain plaster mortar gypsum plaster tile adhesive one 2 3 four 5 6 7 8 9 Components of a complex modifying additive dolomite flour 24 29th one hundred 31 19 36 limestone flour marble flour 25 dusty quartz 33 sand 76 one hundred 75 71 67 69 81 64 cellulose 0.10 0.15 0.15 0.5 0.5 hydroxyethyl cellulose 0.20 0.5 0.3 carboxymethyl cellulose 0.20 0.3 water 8 13 31 fourteen 31 fifty 13 13 43 lemon acid 0.1 0.15 oxalic acid 0.15 lignosulfonate 0.1 S-3 0.2 0.15 polyvinyl acetate 0.05 methyl methacrylate-butyl acrylate copolymer 0.05 calcium stearate 0.05 Cato LXE 0.005 0.005 0.005 mixture of alkylaryl sulfonates 0.01 0.05 The number of components per 100 parts by weight complex modifying additives in the preparation of mortar astringent cement 10 cement 22 cement 19 gypsum 38 gypsum 41 gypsum 45 cement 22 cement 22 cement 35 water twenty 17 - 19 29th - 17 17 - Mortar test results after full cure compressive strength, MPa (GOST 5802-86) 5,0 7.5 7.5 2.0 1,5 3.0 5,0 5,0 10.0 adhesion of the mortar with a brick, MPa (GOST 24992-81) 0.3 0.2 0.5 0.3 0.6 0.5 adhesion of tiles to the base, MPa (GOST 28089-89) 0.5 0.5 1,5

Claims (5)

1. A complex modifying additive for mortar containing a mineral component and cellulose ether as a water-retaining active ingredient, characterized in that it additionally contains water in the following ratio of components, parts by weight:
mineral component one hundred cellulose ether 0.1-1.0 water 8-50 2. The complex modifying additive according to claim 1, characterized in that it contains a mineral filler and / or filler as a mineral component. 3. The complex modifying additive according to claim 1 or 2, characterized in that it contains at least one additional active ingredient selected from the group comprising redispersible polymer powders, as well as water-soluble plasticizing, air-entraining, water-repellent, biocidal, accelerating and mortar retarders, pigmenting additives. 4. A method of obtaining a mortar by mixing a binder with a complex modifying additive, characterized in that use the modifying additive according to any one of claims 1 to 3 in the following ratio of mortar components, parts by weight:
modifying additive one hundred astringent 10-45 5. The method according to claim 4, characterized in that when mixing the binder with a complex modifying additive, water is additionally introduced.