RU2288197C1 - Multicomponent concrete modifier - Google Patents

Abstract

FIELD: production of concrete.

SUBSTANCE: multicomponent concrete modifier comprises, in mass %, 80-98 of dispersed mineral component, 2-20 of plasticizing admixture, and 0-10 of calcium hydroxide. The modifier is additionally comprises air-entraining admixture in amount of 0.01-1.0% of the modifier mass. The plasticizing admixture is made of salt of polycondensate of β- naphthalene sulfo acid and formaldehyde and/or salt of lignosulfonic acid and/or polycarboxylate.

EFFECT: enhanced strength of concrete.

6 cl, 3 tbl

Description

The invention relates to compositions of multicomponent concrete modifiers of multifunctional action.

Known concrete modifier, which allows to obtain high-strength concrete, consisting of silica fume (77.2-94.0 wt.%), Chemical additives (4.7-15.7 wt.%) And water (the rest) (see RU 2096372, publ. 11/20/1997).

The closest in technical essence and the achieved result is a complex concrete modifier, consisting of a dispersed mineral component, which contains silicon dioxide and is a rock and / or gas treatment product of furnaces melting crystalline silicon, and / or ferrosilicon, and / or silicocalcium and / or burning coal, or a mixture of at least one of the above components with the gas treatment product of furnaces smelting ferrosilicon, and as a chemical additive it contains lastifikatory the following component ratio, wt.%:

dispersed mineral component  51.9-94.1 chemical additive  4.7-45.5 water  rest

(see RU 2160723, publ. 20.12.2000).

The disadvantage of this complex modifier is that, contributing to the high grade strength of concrete under axial compression, it does not provide the same increase in strength at an early age and tensile strength in bending, as well as compensation for shrinkage, or expansion, or self-tension of concrete.

The technical task is to develop such a complex modifier that would provide high-strength concrete with increased early strength, including tensile strength when bending in the absence of shrinkage deformation or expansion, or self-stress when using highly mobile concrete mixtures on ordinary Portland cement.

This can be achieved by creating conditions for the formation of additional sulfoaluminate type crystalline hydrates in the cement system, which is ensured, in turn, by optimizing the ratio of silicon, aluminum, calcium, sulfuric anhydride, and water oxides in the modifier.

In connection with the foregoing, the technical problem is solved by the fact that in a complex concrete modifier containing a dispersed mineral component, including rock or its mixture with fly ash and / or gas treatment products of furnaces smelting silicon-containing alloys, and a plasticizing additive, the dispersed mineral component in the quality of the rock includes heat-treated kaolin and gypsum, and the modifier may further include calcium hydroxide in the following ratio of components, wt.%:

dispersed mineral component 80-98 plasticizer 2-20 calcium hydroxide 0-10

which ensures the presence of the following oxides in the modifier at the following content, wt.%:

SiO ₂ 20-66 Al ₂ O ₃ 4-27 SO ₃ 4-26 Cao 3-22 H ₂ O 3-12

In the first version of the modifier, the dispersed mineral component includes heat-treated kaolin and gypsum with the following content, wt.%:

heat treated kaolin 42-68 gypsum 32-58

In the second embodiment, the dispersed mineral component includes a mixture of heat-treated kaolin and gypsum with fly ash at the following content, wt.%:

heat treated kaolin 10-83 gypsum 10-83 fly ash 5-60

In the third embodiment, the dispersed mineral component includes a mixture of heat-treated kaolin and gypsum with gas treatment products of furnaces smelting silicon-containing alloys, with the following content, wt.%:

heat treated kaolin 10-83 gypsum 10-83 products of gas purification of furnaces smelting silicon-containing alloys 5-60

In the fourth embodiment, the dispersed mineral component includes a mixture of heat-treated kaolin and gypsum with fly ash and gas treatment products from furnaces smelting silicon-containing alloys, with the following content, wt.%:

heat treated kaolin 10-78 gypsum 10-78 fly ash 5-60 products of gas purification of furnaces smelting silicon-containing alloys 5-60

The modifier may also optionally contain an air-entraining additive in an amount of 0.01-1.0% by weight of the modifier.

The modifier may also contain, as a plasticizing additive, a salt of a polycondensate of β-naphthalene sulfonic acid and formaldehyde, and / or a salt of lignosulfonic acid, and / or a polycarboxylate.

For the preparation of the complex modifier, dispersed materials were selected which, due to the presence or predominance of SiO ₂ , Al ₂ O ₃ , CaO, SO ₃ , H ₂ O in their compositions, in combination with each other, contribute to the formation of sulfoaluminate crystalline hydrates.

The characteristics of the dispersed materials used are shown in table 1.

1. Natural enriched kaolin (K) from the Glukhovetsky deposit (Ukraine) and the same kaolin subjected to heat treatment at an isothermal holding temperature of 650 ... 800 ° C (CT) were used as a rock.

Heat treatment was carried out in order to obtain X-ray amorphous phases from minerals present in natural kaolin.

2. As a product of gas treatment of furnaces smelting silicon-containing alloys, used pulverized waste production of ferrosilicon (FS) of the Chelyabinsk electrometallurgical plant.

3. As products of gas treatment of coal burning furnaces, fly ash (3-U) was used - pulverized waste from the Reftinskaya state district power station in accordance with GOST 25818 “Fly ash of thermal power plants for concrete. Technical conditions. "

4. As a rock used ground gypsum stone (GK) according to GOST 4013 "Gypsum and gypsum-anhydrite stone for the production of binders. Technical conditions. "

Table 1
Characteristics of Dispersed Mineral Components Name of components Component Designation Loss on ignition (p.p.p.) The content of basic oxides, wt.%: SiO ₂ Al ₂ O ₃ SO ₃ Cao H ₂ O MgO Fe ₂ O ₃ Na ₂ O K ₂ O TiO ₂ MnO P ₂ O ₅ CO ₂ Kaolin TO 13.50 47.60 34.80 0.02 0.08 1,04 0.4 1.7 0.1 0.06 0.35 - 0.13 - Heat treated kaolin CT 0.65 54.70 40.00 0,03 0.09 1.20 0.1 2.27 0.2 0,07 0.46 0.23 Ferrosilicon production waste FS 4.77 90.40 1.25 0.02 0.41 1.80 0.5 0.2 0.42 0.15 0.01 0.06 Fly ash 3-U 2.73 57.00 28.80 0.05 2,34 2.00 1.71 4.28 0.54 0.45 - 0.08 - - Gypsum G - - - 46.50 34.00 19.50 - - - - - - - - Lime AND - - - - 98.20 0.80 - - - - - - - 1,0

5. As a substance containing calcium hydroxide, lime (I) hydrated (slaked) air was used in accordance with GOST 9179 “Building lime. Technical conditions. "

In addition to the above dispersed materials, the chemical additives below were used.

1. As a sulfonated naphthalene formaldehyde polycondensate, a powdery superplasticizer of grade S-3 was used according to GOST 24211 “Additives for concrete. General technical requirements ”, corresponding to the plasticizing additive of group I.

2. As a lignosulfonate, powdered technical lignosulfonate was used according to GOST 24211, corresponding to a plasticizing additive of group II.

3. As a polycarboxylate, the ViscoCrete-105 Pulver additive was used, which is a copolymer based on oxyethylene and oxypropylene compounds and according to GOST 24211 corresponding to a plasticizing additive of group I.

4. As an air-entraining additive, a neutralized air-entraining resin — START — that meets the requirements of GOST 24211, was used.

From the above dispersed materials and chemical additives in a high-speed mixer, samples of modifiers were prepared, which were loose powder compositions differing in the ratio of components.

Table 2 shows the material compositions and ratios of the main components of the prepared modifier samples.

Samples No. 1 and No. 2, including waste from the production of ferrosilicon, fly ash, kaolin and plasticizers prepared according to the patent prototype, were control, the rest of the samples (No. 3-27) were prepared in accordance with the proposed technical solution.

Using samples of modifiers, fine-grained concrete mixtures of different mobility were prepared with dosages of modifiers from 10 to 50% by weight of cement. The compositions and characteristics of concrete mixtures are given in table 3. The compositions of the modifiers in the samples of the concrete mixture correspond to the compositions of the samples of modifiers shown in table 2 under the corresponding numbers.

Portland cement M500 DO, quartz sand M _cr = 2.5, modifier samples with different component ratios were used as components of fine-grained concrete mixtures (Table 2).

From concrete mixtures prepared:

- cube samples with dimensions of 70.7 × 70.7 × 70.7 mm for determining the tensile strength under axial compression;

- prism samples with dimensions of 70 × 70 × 280 mm to determine the tensile strength in bending;

prism samples 40 × 40 × 160 mm in size to determine expansion strains;

- prism samples with dimensions of 31.5 × 31.5 × 95 mm in dynamometric rings to determine the magnitude of self-stress.

The mobility of concrete mixtures was evaluated by cone settlement according to GOST 10181.1.

The values of compressive and bending strengths were determined according to GOST 10180 “Concretes. Methods for determining the strength of control samples. "

Indicators of linear expansion and self-stress were determined according to TU 5743-157-46854090-2003 “Cement straining. Technical conditions. "

Strength tests were carried out at the ages of 1 and 28 days of normal hardening of concrete (t = 20 ± 2 ° C, W = 98%), and the values of expansion strains and self-stress were measured for 28 days when the samples were kept in water.

table 2
The material and chemical composition of modifiers No. of composition The ingredients of the dispersed mineral component (DMK), wt.% The material composition, wt.% The ratio of oxides, wt.% AND DMK chemical additive SiO ₂ Al ₂ O ₃ SO ₃ Cao H ₂ O Ingredients CT FS TO G ZU LST S-3 VC-105P START Total Prototype Samples one - fifty - - fifty - 90 2 8 - - 10 66.33 13.52 0,03 1.24 1.71 2 - 44 12 - 44 - 90 2 8 - - 10 63.72 15,5 0,03 1,11 1,62 Samples for the proposed solution 3 67 - - 22 eleven - 90 - - 10 - 10 38.52 26.88 9.03 7.08 4.82 four 63 - - 37 - 6 86 four 10 - - fourteen 27.35 20.00 13.97 16.14 6.49 5 44 - - 44 12 - 90 2 8 - - 10 27.58 18.88 18.62 13.87 8.48 6 44 - - 44 12 - 90 2 6 2 - 10 27.58 18.88 18.62 13.87 8.48 7 44 - - 44 12 - 90 2 6 1.7 0.3 10 27.58 18.88 18.62 13.87 8.48 8 44 - - 44 12 - 90 - 7 3 - 10 27.58 18.88 18.62 13.87 8.48 9 44 - - 44 12 - 90 7 - 3 - 10 27.58 18.88 18.62 13.87 8.48 10 44 - - 44 12 - 90 10 - - - 10 27.58 18.88 18.62 13.87 8.48 eleven 44 - - 44 12 - 90 - 10 - - 10 27.58 18.88 18.62 13.87 8.48 12 44 - - 44 12 - 90 - - 10 - 10 27.58 18.88 18.62 13.87 8.48 13 42 - - 58 - - 94 - - 6 - 6 21.33 15.60 25.58 18.74 11.20 fourteen 53 - - 47 - 10 80 - twenty - - twenty 20,23 14.80 15.35 21.07 6.96 fifteen 35 eleven - 43 eleven one 94 four 2 - - 6 32.79 16.21 18.62 14.89 8.58 16 25 25 - 25 25 2 90 - 10 - - 10 44.46 15.41 10.25 10.07 5.40 17 25 25 - 25 25 2 90 2 8 - - 10 44.46 15.41 10.25 10.07 5.40 eighteen 22 56 - 22 - one 91 3 6 - - 9 56.14 8.63 9.32 8.01 5.05 19 22 - - 22 56 - 90 - 10 - - 10 39.44 22.40 9.33 7.99 5.14 twenty 26 35 - 26 13 2 80 - twenty - - twenty 41.95 11.23 9.32 9.13 4.86 21 17 33 - 17 33 - 90 2 8 - - 10 52,43 15.02 7.00 5.94 4.25 22 eleven eleven - eleven 67 8 98 2 - - - 2 48.71 21.41 4.69 12.71 9.75 23 eleven eleven - eleven 67 8 98 1.98 - - 0.02 2 48.71 21.41 4.69 12.71 9.75 24 eleven eleven - eleven 67 8 98 - 2 - - 2 48.71 21.41 4.69 12.71 9.75 25 eleven eleven - eleven 67 8 98 - - 2 - 2 48.71 21.41 4.69 12.71 9.75 26 12.5 75 - 12.5 - - 80 - twenty - - twenty 59.71 4.75 4.67 3.66 3.27 27 eleven 67 - eleven eleven one 91 6 3 - - 9 65.41 7.63 4.67 4.87 3.47

Table 3 shows the results of testing concrete prepared using modifiers of various compositions. From the results it follows that samples No. 3-27, prepared using the proposed multicomponent modifiers, differ from the control (prepared according to the prototype) a number of significant advantages:

- increased by 12-44% early (at the age of 1 day) compressive strength;

- increased by 26-43% early (at the age of 1 day) tensile strength during bending;

- increased compressive strength (by 13-44%) and tensile bending (by 12-38%) at the age of 28 days;

- linear expansion in the range of 0.05-0.13% and self-tension in the range of 1.0-2.1 MPa at the age of 28 days.

All these advantages were shown by samples prepared from mixtures with a mobility similar to the control.

The effects obtained are the result of optimizing the ratio between the main oxides (SiO ₂ , Al ₂ O ₃ , SO ₃ , CaO, H ₂ O) contained in the dispersed components of the modifier, which contribute to the formation of calcium hydrosulfoaluminates (ettringite), which lead not only to an increase in strength, but and to expand the cement system. The increased mobility of the mixtures is ensured by optimizing the ratio between the dispersed mineral component and chemical additives.

Thus, the stated technical problem is solved by a multicomponent composition - a complex modifier, which contains the selected ingredients in optimal proportions.

Claims (7)

1. A complex modifier of concrete containing a dispersed mineral component, including rock or its mixture with fly ash and / or with gas treatment products of furnaces smelting silicon-containing alloys, and a plasticizing additive, characterized in that the dispersed mineral component as a rock includes subjected heat-treated kaolin and gypsum and the modifier may additionally include calcium hydroxide in the following ratio, wt.%: Dispersed Mineral Component 80-98 Plasticizing additive 2-20 Calcium hydroxide 0-10 which ensures the presence of the following oxides in the modifier at the following content, wt.%: SiO ₂ 20-66 Al ₂ O ₃ 4-27 SO ₃ 4-26 Cao 3-22 H ₂ O 3-12 2. The modifier according to claim 1, characterized in that the dispersed mineral component includes heat-treated kaolin and gypsum with the following content, wt.%: Heat treated kaolin 42-68 Gypsum 32-58 3. The modifier according to claim 1, characterized in that the dispersed mineral component comprises a mixture of heat-treated kaolin and gypsum with fly ash at the following content, wt.%: Heat treated kaolin 10-83 Gypsum 10-83 Fly ash 5-60 4. The modifier according to claim 1, characterized in that the dispersed mineral component includes a mixture of heat-treated kaolin and gypsum with gas treatment products of furnaces smelting silicon-containing alloys, at their following content, wt.%: Heat treated kaolin 10-83 Gypsum 10-83 Gas treatment products of smelting furnaces silicon alloys 5-60 5. The modifier according to claim 1, characterized in that the dispersed mineral component comprises a mixture of heat-treated kaolin and gypsum with fly ash and gas treatment products of furnaces smelting silicon-containing alloys, with the following content, wt.%: Heat treated kaolin 10-78 Gypsum 10-78 Fly ash 5-60 Gas treatment products of smelting furnaces silicon alloys 5-60 6. The modifier according to claim 1, characterized in that it further comprises an air-entraining additive in an amount of 0.01-1.0% by weight of the modifier. 7. The modifier according to claim 1, characterized in that as a plasticizing additive it contains a salt of polycondensate β-naphthalene sulfonic acid and formaldehyde, and / or a salt of lignosulfonic acid, and / or polycarboxylate.