RU2308428C1 - Clinkerless binder - Google Patents

Abstract

FIELD: manufacture of building materials, namely clinkerless binders on base of perlite rocks; manufacture of silica brick, dense and cellular silicate concretes and articles on their base.

SUBSTANCE: proposed binder contains perlite, unslaked lime, gypsum and it additionally contains additive - grinding intensifying agent in form of surfactant - superplasticizing agent C-3 at the following ratio of components, mass-%: perlite, 60-69; unslaked lime, 26-35; gypsum, 3.8-4.2; superplasticizing agent C-3, 0.8-1.2.

EFFECT: enhanced strength of binder; reduced water-to-binder ratio at similar plasticity; reduction of time required for mechanical activation due to intensification of grinding; reduction of sintering processes; reduction of time required for treatment of clinkerless binder.

4 tbl, 3 ex

Description

The invention relates to the building materials industry, and in particular to clinker-free binder compositions based on perlite rocks, which can be used in the production of silicate brick, dense and cellular silicate concrete and products based on them.

Known clinker-free binder from crushed volcanic rocks with the addition of quicklime and gypsum. The composition of the known binder, wt.%: Quicklime - 16-20; gypsum - 4-8; volcanic rock - 72-80. The clinker-free binder is prepared by co-grinding to a dispersion of 400-450 m ² / kg of the constituent materials. The mixture is shut with water, molded and subjected to heat-moisture treatment. The obtained silicate stone based on a known binder has a strength of at least 35 MPa (see Merkin A.P., Romazanov V.A., Zeifman M.I. Non-autoclaved aerated concrete with a cementless binder. Builds. Materials, 1989. 11. C. 11-12).

The disadvantage of this binder is the reduced strength of the resulting silicate stone.

The closest in technical essence and the achieved result to the proposed invention is a lime-silica binder with the use of vitreous perlite of the Mukhor-Talinsky deposit (Republic of Buryatia). To obtain astringent perlite, quicklime and two-water gypsum are subjected to joint grinding (mechanical activation) in various types of activators, for example, in a drum, planetary mill, in a vibration eraser and in a disintegrator. The composition of the binder, wt.%: Perlite - 70-80, quicklime - 16-22, two-water gypsum - 4-8.

The compressive strength of the binder obtained as a result of heat-moisture treatment at 90 ° C and the regime of 1.5 + 8 + 1.5 hours, depending on the type of activator, was at S _beats = 500 m ² / kg, respectively, when grinding in a ball mill for 6 hours - 28 MPa, in a planetary mill for 15 s - 29 MPa, in a vibration eraser for 45 s - 34 MPa and in a disintegrator - 22 MPa (see Urkhanova L.A. Activated calc-siliceous binders and products based on them The abstract of the candidate dissertation. - M .: ROTEX, 1996).

The disadvantages of the specified composition of calcareous perlite binder include reduced strength and a relatively large period of heat and moisture treatment (TVO).

The problem solved by the invention is to obtain a clinkerless lime-perlite binder based on perlite rocks of Transbaikalia with the possibility of its use in the production of silicate brick, dense and cellular silicate concrete and products based on them.

The technical result of the invention is to increase the strength characteristics, reduce the water-binder ratio with the same ductility, reduce the time of mechanical activation due to the intensification of grinding, reduce agglomeration processes in the binder during grinding, and reduce the heat-moisture treatment.

To achieve the technical result provided by the invention, a clinker-free binder containing perlite, quicklime, gypsum, according to the invention, additionally contains a grinding enhancer, which is used as a surface-active substance - superplasticizer S-3, in the following ratio, wt.%:

quicklime - 26-35;

perlite - 60-69

gypsum - 3.8-4.2

superplasticizer C-3 - 0.8-1.2.

A distinctive feature of the proposed clinker-free binder is the introduction of an additive - grinding intensifier, which uses a surface-active substance - superplasticizer S-3 in an amount of 0.8-1.2 wt.%, Which allows to reduce the effect of agglomeration, to intensify the grinding in grinding process.

It is the introduction of a surfactant - superplasticizer S-3 in the amount, wt.%: 0.8-1.2 in combination with other components of a clinker-free binder: perlite - 60-69; lime - 26-35; gypsum - 3.8-4.2 ensure the achievement of a technical result, which consists in increasing strength indicators; decrease in water-binding ratio with the same plasticity; reducing the time of mechanical activation due to the intensification of grinding from 15 to 1.5 minutes; reduction of agglomeration processes in the binder during grinding; reduction of heat and moisture treatment.

An increase in the strength indicators of a clinker-free binder by 30% occurs due to a decrease in the water-binder ratio with the same plasticity of the dough, which reduces the porosity of silicate stone.

When a S-3 superplasticizer — less than 0.8 wt.% — Is introduced into the composition of a clinker-free binder, the effect of reducing the agglomeration of binders during grinding, intensification of grinding, and increase in strength properties are not observed.

And with its introduction of more than 1.2 wt.%, The hydration and hardening processes of clinker-free binders slow down, especially at the initial stages of hardening, and there is no increase in strength.

A quantitative change in the components of a clinker-free binder (wt.%) Perlite 60-69, lime 26-35, gypsum 3.8-4.2 allows you to vary the composition of a clinker-free binder without a noticeable change in strength indicators.

Deviation of the lime content from the specified limits to a smaller side leads to the fact that in the binder composition during mixing, calcium hydrosilicates are not formed in sufficient quantities. The result is a low strength of the obtained samples. A deviation of the lime content up leads to supersaturation of the binder mixture with calcium hydroxide, which in large quantities leads to a decrease in the strength of the samples, and to an increase in energy costs for the production of binders, since lime is an energy-intensive component.

The components of the clinker-free binder are selected in such a way that the samples obtained have maximum strength indicators.

With an increase in the grinding time of binders, an increase in the interaction force of freshly formed surfaces upon contact occurs. Activation manifests itself here in that the number of particles destroyed at the moment and sticking together is almost the same. In this grinding mode, the specific surface practically does not grow, i.e. as particle sizes decrease, agglomeration of freshly formed surfaces with the formation of molecular-dense aggregates plays an increasingly important role. Aggregate instability of powders is due to excess surface energy.

The effect of agglomeration is associated with the so-called uniformity coefficient, which depends on the properties of the material. During the grinding process, as the homogeneity coefficient decreases, the agglomeration becomes more intense, and the increase in the specific surface can be achieved by a significant increase in the energy consumed, that is, excess energy causes agglomeration. Thus, an excess of energy causes agglomeration, its insufficient amount does not allow for fine grinding.

There are practical options for reducing the agglomeration rate of materials. So, the introduction of grinding intensifiers (sulphite-alcohol stillage, triethanolamine, etc.) causes a decrease in the adhesion forces of the grinding products and, accordingly, its ability to agglomerate, as well as a change in its properties (G. Khodakov, Grinding physics. - M. -Mathematical literature of the publishing house "Science", 1972).

Therefore, to reduce the effect of agglomeration and to intensify grinding before mechanical activation, the grinding binder is introduced into the composition of the proposed binder, which is used as a surfactant - superplasticizer C-3 (in wt.%: The condensation product of naphthalene sulfonic acid and formaldehyde - 60-99, 8; sodium sulfate - 0.1-20; lignosulfanate - 0.1-20).

The surfactant S-3 superplasticizer (GOST 24211-2003) has 3 main properties that characterize its use in the production of building materials: a decrease in water-binding ratio with the same plasticity as compared with a cementing composition without plasticizer, which is expressed by an increase in strength characteristics; increasing the mobility of mortars and concrete, and plasticity with the same water-binding ratio, which allows concreting densely reinforced and conventional structures practically without the use of vibrators and to obtain a smooth high-quality front surface of products of various shapes; reduction of cement consumption (by 20%) in the composition of mortars and concrete.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information and identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find a source characterized by signs identical to all the essential features of the claimed composition of a clinker-free binder. The definition from the list of identified analogues of the prototype, which is closer to the totality of the features of the analogue, made it possible to establish a set of significant distinguishing features set forth in the form of the invention with respect to the technical result perceived by the applicant.

Therefore, the claimed invention meets the conditions of "novelty" and "inventive step".

To obtain the proposed clinker-free binder, perlite of the Mukhor-Talinsky deposit is used, with a content, wt.%: SiO ₂ - 71.4; Al ₂ O ₃ - 12.1; CaO - 0.57; Fe ₂ O ₃ - 0.77; MgO - 0.39; K ₂ O - 3.24; Na ₂ O - 5.23; FeO — 0.43; p.p.p. - 5.87; quicklime (GOST 9179-77) and gypsum (GOST 125-79).

Prepare three mixtures of components, wt.%: Quicklime - 26-35; perlite - 60-69; gypsum - 3.8-4.2; superplasticizer C-3 - 0.8-1.2 (compositions 1-3), respectively. The activity of binders (CaO content) was in the range: 10-28 wt.%. At the same time, four mixtures of binder components are prepared with a prohibitive content of lime, perlite, gypsum and S-3 superplasticizer to confirm optimality (compositions 4 and 5). In addition, two known binder compositions are prepared using perlite and lime: 61-83 and 13-35 (formulations 6 and 7), respectively (see table 1).

Table 1 Binder Compounds No. comp. The content of components, wt.% Perlite Quicklime Gypsum Superplasticizer S-3 Proposed one 69 26 3.8 1,2 2 65 thirty four one 3 60 35 4.2 0.8 For optimality four 75 21 3,5 0.5 5 45 48.5 5 1,5 Famous 6 83 13 four - 7 61 35 four -

Mixtures of clinker-free binder compositions (1, 2, 3, 4, 5) are subjected to joint mechanical activation in a vibration eraser to a specific surface of 500 m ² / kg for 1.5 min. To determine the properties of the obtained binders by the method of plastic molding, 2 × 2 × 2 cm cubes are prepared. When mixed with the same plasticity, the water demand of the binder is reduced in comparison with the known composition. When forming samples, the water-binder ratio with the same ductility decreases, and is 0.23.

Strength test samples are steamed at 90 ° C according to the regime of 1.5 + 8 + 1.5 hours and tested at the age of 3 and 28 days.

The obtained binder compositions had the following characteristics (see table 2).

The introduction of a clinker-free binder additive - an intensifier for grinding a surfactant - superplasticizer S-3 allows to reduce the regime of TBO. Samples are prepared in the same way as when comparing the compositions. Heat and humidity treatment is carried out at 90 ° C in three modes: 1.5 + 8 + 1.5 hours, 1.5 + 7 + 1.5 hours, 1.5 + 6 + 1.5 hours and tested at the age of 28 days. Table 3 presents the physicomechanical characteristics of the binder (compositions 1, 2, 3) at low TVO modes.

table 2 Composition No. The limit of compressive strength, MPa In age 3 days after TVO In age 28 days after TVO one 36.9 41.8 2 37.9 43.6 3 40.5 44.6 four 24.6 28,4 5 29.1 32.8 6 21.3 24.1 7 27.6 30.9

Table 3 The compressive strength after TVO at t = 90 ° C, MPa No. Time Time Time compositions isothermal isothermal isothermal excerpts, 8 7 extracts excerpts, 6 hour hour hour one 41.8 41.6 37.0 2 43.6 43.1 37.8 3 44.6 44.1 38.7

An analysis of the results (Tables 2 and 3) allows us to draw the following conclusions:

- the strength of the artificial stone based on the proposed clinker-free binder increases from 30 MPa without mechanical activation and from 44 MPa with the use of mechanical activation;

- to a greater extent, mechanical activation contributes to the increase in strength when the content of active CaO in the amount of 10-28% (increase in the content of active CaO over 28% is impractical due to a decrease in the strength of the stone, a decrease in CaO content below 10% also leads to a similar result);

- a decrease in the TWT time from 8 to 7 hours reduces the strength of the samples to 2%, and a decrease to 6 hours - up to 14%;

- a decrease in water-binder ratio compared to a binder with a known composition. With the same plasticity of the closed clinker-free binder, the water-binder ratio is 0.23, while on the known composition it is 0.33.

The proposed clinker-free binder is prepared as follows.

Perlite, quicklime, gypsum and C-3 superplasticizer are pre-mixed, and then subjected to joint mechanical activation in a vibration eliminator to a powder state with S _beats = 500 m ² / kg. The content of components in the mixture, wt.%: Quicklime - 26-35; perlite - 60-69; gypsum - 3.8-4.2; superplasticizer C-3 - 0.8-1.2. The components are closed with water at a water-binding ratio of 0.23 and mixed thoroughly. After mixing the mixture, the products are molded into samples 2 × 2 × 2 cm in size by plastic molding. The samples are subjected to TBO at 90 ° C according to the regime of 1.5 + 6 + 1.5 hours.

Example 1. Perlite, quicklime, gypsum and C-3 superplasticizer are pre-mixed, and then subjected to joint mechanical activation in a vibration eraser to a powder state with S _beats = 500 m ² / kg. The content of components in the mixture, in wt.%:

1. Perlite - 69

2. Quicklime - 26

3. Plaster - 3.8

4. Superplasticizer C-3 - 1.2.

The components are closed with water at a water-binding ratio of 0.23 and mixed thoroughly. After mixing the mixture, the products are molded into samples of 2 × 2 × 2 cm by plastic molding. The samples are subjected to TBO at 90 ° C according to the regime of 1.5 + 6 + 1.5 hours.

The compressive strength at the age of 28 days is 37.0 MPa.

Example 2. Carried out analogously to example 1 in the following ratio of components, wt.%:

1. Perlite - 65

2. Quicklime - 30

3. Plaster - 4

4. Superplasticizer C-3 - 1.

The compressive strength at the age of 28 days is 37.8 MPa.

Example 3. Carried out analogously to example 1 in the following ratio of components, wt.%:

1. Perlite - 60

2. Quicklime - 35

3. Plaster - 4.2

4. Superplasticizer C-3 - 0.8.

The compressive strength at the age of 28 days is 38.7 MPa.

Table 4 shows comparative data on the characteristics of the binder obtained according to the invention in comparison with the prototype (see Urkhanova L.A. Activated calc-siliceous binders and products based on them. Abstract of the candidate dissertation. - M .: ROTEKS, 1996) .

Table 4 Binder Composition Numbers The limit of compressive strength, MPa TVO mode at t = 90 ° C, hour one 41.8 1.5 + 8 + 1.5 2 43.6 1.5 + 8 + 1.5 3 44.6 1.5 + 8 + 1.5 one 37.0 1.5 + 6 + 1.5 2 37.8 1.5 + 6 + 1.5 3 38.7 1.5 + 6 + 1.5 Prototype 22-34 1.5 + 8 + 1.5

Thus, the proposed composition for producing a clinker-free binder with the introduction of additives - surfactants - superplasticizer S-3 in an amount (wt.%) Of 0.8-1.2 in conjunction with other components of a clinker-free binder: perlite - 60-69; lime - 26-35; gypsum - 3.8-4.2 has the following advantages compared to the prototype (see Urkhanova L.A. Activated calc-siliceous binders and products based on them. Abstract of the Ph.D. thesis. - M .: ROTEKS, 1996):

- increase in strength indicators, compared with the prototype, due to a decrease in porosity due to the introduction of a surfactant - superplasticizer S-3;

- a decrease in the water-binding ratio compared to the prototype with the same ductility due to the properties imparted by the surfactant to the cementitious composition — C-3 superplasticizer;

- reduction of the time of mechanical activation compared with the prototype due to the intensification of grinding from 15 to 1.5 minutes with a surface-active substance - superplasticizer S-3;

- reduction of agglomeration processes in comparison with the prototype in the binder during grinding by reducing the adhesion forces of the grinding products when using a surfactant - superplasticizer S-3;

- reduction of the moisture-moisture treatment mode in comparison with the prototype due to the properties obtained by the binder composition with the introduction of a surfactant - superplasticizer S-3.

The proposed method for producing a composite binder can be used in the building materials industry to obtain silicate brick, dense and cellular silicate concrete and products based on them, which allows us to conclude that the proposed invention meets the criterion of "industrial applicability".

Claims (1)

Clinker-free binder, including perlite, quicklime, gypsum, characterized in that it additionally contains an additive - grinding intensifier, which is used as a surfactant superplasticizer C-3 in the following ratio, wt.%: Perlite 60-69 Quicklime 26-35 Gypsum 3.8-4.2 Superplasticizer S-3 0.8-1.2