RU2278085C1 - Method for controlling of concrete mixture air-entraining - Google Patents

Abstract

FIELD: building materials.

SUBSTANCE: claimed method includes additive introducing together with tempering water. As said additive complex organomineral mixture based on saponified lignine and fine material from cement production waste is used. Paste lignine is previously mixed with cement dust in the mass ratio of paste saponified lignine 40-50; cement dust 50-60; mixture is granulated, dried at 60-70°C up to constant mass and introduced into concrete mixture in amount of 0.003-1.2 % based on cement mass.

EFFECT: method of improved dosage accuracy; concrete mixture air-entraining with decreased variation coefficient; additive of prolonged storage time.

1 ex, 2 tbl

Description

The invention relates to building materials and relates to a method for controlling the air entrainment of a concrete mixture by introducing with water mixing a complex organomineral additive based on a product of wood chemical production and finely dispersed material - a waste of cement production.

The closest in technical essence is a method of regulating the air entrainment of a concrete mixture by introducing with water a mixing additive of tall saponified lignin (LTO) based on products of wood chemical production obtained by alkaline treatment of tall waste decomposition of sulfate soap, in an amount of 0.001-0.3% of the mass of cement ( SU 1588724 A1, 08/30/90, bull. No. 32).

The disadvantage of this method of regulating the air entrainment of the concrete mixture is the sensitivity of the additive to dosing, which is associated with the high efficiency of the additive at minimum dosages. It is especially inconvenient in such circumstances to prepare small volumes of batches. The existing paste-like additive LTO cannot be used in the manufacture of ready-to-use dry mortar. Transportation over long distances and storage of the additive at low freezing temperatures makes it difficult to use in winter conditions.

An object of the invention is to reduce the coefficient of variation while providing an air-entraining effect in cement materials, ensuring metering accuracy for small volumes of batches and the possibility of transporting the additive over long distances and its storage at low negative temperatures without reducing the main air-entraining effect of the additive.

The technical result is achieved by the fact that the regulation of air entrainment in cement mixtures occurs by introducing with water a mixing additive of tall saponified lignin, which is pre-mixed with cement dust in the following ratio of components, wt.%:

Paste-shaped lignin tall saponified 40-50

Cement dust 50-60

granulated, dried at a temperature of 60-70 ° C to constant weight and introduced into the concrete mixture in an amount of 0.003 ÷ 1.2% by weight of cement.

Tallow waste is generated during the process of decomposition of sulfate soap with sulfuric acid in order to isolate tall oil and is a dispersed system, which includes fatty and resin acids, neutral substances, lignin, sodium busulfate and water.

Tallow wastes have a moisture content of 20-50%, an ash content of 1-7%, an acid number of 50-110 mg KOH / g, a saponification number of 80-140 mg KOH / g and contain 30-75% of fatty resin neutral substances, 25-30% of tar substances, 2-15% lignin and 0.5-5.0% fiber.

Cement dust is a waste of cement production resulting from the grinding of clinker and additives. It is a fine powder of light gray color with a large specific surface.

Physical properties of cement dust

Color light gray True density 2.63 g / cm ³ Bulk density 860 kg / m ³ Specific surface area 800-1000 m ² / kg Sieve residue 008 no Toxicity non toxic

A complex organomineral additive based on LTO and cement dust is introduced into the composition of cement materials together with mixing water in the form of granules or in dry building mixtures in the form of powder.

Example. Tallow waste from the decomposition of sulfate soap was treated with alkali under the following conditions: temperature 60-80 ° C, alkali consumption of NaOH 8-12% by weight of dry matter, mixing was carried out in a laboratory mixer with a shaft speed of 1000-1400 rpm for 20- 30 minutes.

The mass fraction of dry matter of tall oil saponified lignin ranges from 40-60% and depends on the initial properties of tall lignin. It is possible to regulate the mass fraction of dry matter of LTO additives by changing the water content in it.

For convenience, LTE of 50% concentration was used.

Tall saponified lignin was mixed with cement dust in the following ratio of components, wt.%:

Tall saponified lignin paste 50

Cement dust 50

The process of preparing a complex organomineral additive included the following operations: selection of the optimal ratio of the components of the additive; mixing the mixture; granule molding; drying. The ratio of the components of the complex organomineral additive was determined empirically so that the resulting mixture was homogeneous and plastic, not sticky to the molding equipment, when forming the granules were obtained close in size.

Weighed components were mixed until a homogeneous plastic mass. The resulting mixture was subjected to molding. The process of forming granules was carried out using equipment in the form of a screw with a hole nozzle. The diameter of the nozzle holes was 5 mm. When passing through the nozzle under the influence of gravity, the resulting mixture disintegrated into cylindrical granules with a length of 4-5 cm. The additive was dried at a temperature of 60-70 ° C to constant weight for 2-3 hours.

To confirm the technical result, concrete mixtures were prepared heavy and light, changing the volume of the batch. Used cement Angarsk M400 D20. As a fine aggregate - fraternal quartz sand with a particle size modulus of 2.14. Coarse aggregate - crushed stone diabase plant non-metallic building materials, fractions 5-20 mm. Porous aggregate - expanded clay, bulk density = 540-560 kg / m ³ , fractions 5-20 mm.

Concrete mixtures were tested on dense and porous aggregates of the following composition:

- Cement: sand: crushed stone = 1: 2,3: 4,26 V / Ts = 0,59,

- Expanded clay 0.9-1.1 m ³ , cement 220 kg / m ³ , sand 350 kg.

10 lots of concrete were produced in volumes of 10 l, 100 l and 1000 l.

The test results are presented in tables 1 and 2.

Controls were mixtures without additives in accordance with recommendations for evaluating the effectiveness of additives.

Conclusion: the regulation of air entrainment in cement concrete mixtures by introducing with water mixing a pre-granulated additive of tall oil saponified lignin can reduce the coefficient of variation while providing an air-entraining effect in cement materials and ensure metering accuracy for small volumes of mixes.

Table 1
The results of air entrainment into concrete mixes on dense aggregates Air entrainment method Kneading volume, l The amount of additive,% of C The amount of air involved for lots of concrete,% s The coefficient of variation air entraining component Total one 2 3 four 5 6 7 8 9 10 Control 10 0 0 1,2 1,5 1.3 1,6 1,1 1,2 1,5 1.3 1.4 1,5 12.11 Prototype 0.001 0.001 2,5 2,3 1.9 2,4 2,5 2.7 2,8 1.8 2,4 2,3 13.28 0.015 0.015 5,4 6.2 5.8 5.3 6.5 5.2 4.8 5.7 5,4 5,0 9.53 0,03 0,03 6.7 7.4 8.2 7.5 7.0 7.9 7.1 7.6 7.7 8.0 6.29 According to the proposed method 0.001 0.003 2,5 2,4 2.6 2,5 2.6 2,5 2,4 2,5 2,5 2.6 2.94 0.015 0,045 5,4 5.3 5,6 5,4 5.3 5,4 5,6 5,4 5.3 5,4 2.03 0,03 0.09 7.7 7.7 7.6 7.8 7.7 7.8 7.7 7.7 7.8 7.6 0.96 Control one hundred 0 0 1,2 1,5 1.3 1.8 1.4 1,6 1,5 1,6 1.4 1,5 11.40 Prototype 0.001 0.001 2,5 2.0 2,4 2.7 2,3 2.6 2.7 2,5 3.0 2,5 10.55 0.015 0.015 5,4 5.3 6.6 5,4 6.2 5.5 5,6 5.3 5.7 7.0 10.28 0,03 0,03 7.7 7.6 7.5 8.1 7.6 8.0 7.5 7.8 9.0 7.8 5.70 According to the proposed method 0.001 0.003 2,5 2,4 2,4 2,5 2,5 2,4 2,5 2.6 2,5 2.6 2.96 0.015 0,045 5,4 5,4 5.5 5,4 5.3 5,4 5.5 5,4 5,4 5.5 1.17 0,03 0.09 7.7 7.8 7.7 7.7 7.7 7.6 7.8 7.7 7.8 7.6 0.96 Control 1000 0 0 1,2 1,5 1,5 1,6 1.3 1,6 1,5 0.8 1.4 1,5 17.44 Prototype 0.001 0.001 2,5 2,3 2.6 2,4 2,5 2.6 2,4 2.6 2,3 2,5 4.69 0.015 0.015 5,4 5,6 5,4 5.5 5,0 5,4 5,6 5.3 5.5 6.5 6.98 0,03 0,03 7.7 7.5 8.5 7.6 7.6 7.3 8.0 7.5 7.1 7.8 5.04 According to the proposed method 0.001 0.003 2,5 2,5 2,5 2,4 2,5 2,4 2,4 2,5 2,4 2,5 2.10 0.015 0,045 5,4 5.3 5,4 5,4 5.3 5,4 5.3 5.3 5,4 5,4 0.96 0,03 0.09 7.7 7.7 7.8 7.7 7.8 7.7 7.8 7.7 7.7 7.8 0.67

table 2
Results of air entrainment into concrete mixes on porous aggregates Air entrainment method Kneading volume, l The amount of additive,% of C Volume of additional air involved for concrete batches,% s Coefficient of variation air entraining component Total one 2 3 four 5 6 7 8 9 10 Control 10 0 0 bulk density of expanded clay mixture 1400 kg / m ³ - Prototype 0.01 0.01 7.1 8.3 9.2 7.3 7.8 6.5 8.4 7.5 7.1 9,4 12.07 0.15 0.15 21,4 19.1 18.3 22.8 23.1 24.3 25.5 20.3 20,4 23.0 10.58 0.3 0.3 25,4 26.0 26.8 30,0 30.8 27.1 29.2 26.3 26.3 27.7 6.65 According to the proposed method 0.01 0,03 8.1 7.0 7.5 7.6 8.3 7.9 8.0 8.5 8.2 7.8 5.55 0.15 0.45 20.8 22.1 22.8 21.6 21.0 22.3 23.1 21,4 21.6 20.5 3.92 0.3 0.9 * 24.5 25.8 26.1 25,2 25.9 26.3 26.0 25.0 24.6 27.0 3.10 * - when making an additive from pasty lignin of tall saponified lignin with a concentration of 40%, the dosage of the granular additive increases to 1.2% by weight of cement.

Claims (1)

A method of regulating the air entrainment of a concrete mixture by introducing with water a mixture of thawed saponified lignin additive, characterized in that the previously paste-like thawed saponified lignin is mixed with cement dust in the following ratio of components, wt.%: Paste-shaped lignin, tallow 40-50 Cement dust 50-60 granulated, dried at a temperature of 60-70 ° C to constant weight and introduced into the concrete mixture in an amount of 0.003-1.2% by weight of cement.