RU2266271C1 - Method of production of heat-insulating cellular concrete (versions) - Google Patents

Abstract

FIELD: manufacture of building materials; production of heat-insulating cellular concretes.

SUBSTANCE: according to first version, first water at ratio of W/S=0.5-0.65 is fed to mixer, then sand and synthetic anion-active foaming agent in the amount of 0.08-0.1% of mass of solid components is introduced and components are mixed for 1.5-2.3 min, after which cement is introduced and components are mixed to complete air-entrainment of mix; solid components are introduced at the following ratio, mass-%: sand, 30-35; cement, 65-70. According to second version, first water in the amount of W/S=0.6-0.75 is fed to mixer; perlite of fine fraction is introduced as silica component and anion-active synthetic foaming agent is additionally introduced in the amount of 0.08-0.1% of mass of solid components; components are mixed for 1.5-2.3 min; then cement is introduced and mixing is continued till complete air-entrainment of mix; solid components are introduced at the following ratio, mass-%: perlite, 1-3; cement, 97-99.

EFFECT: reduction of shrinkage deformation, density and heat conductivity of cellular concrete with no impairment of its strength; reduced consumption of foaming agent and cement.

3 cl, 2 tbl, 1 ex

Description

The invention relates to building materials and can be used for the preparation of cellular concrete in the manufacture of heat-insulating building products, for thermal insulation devices and in monolithic construction.

A known method of producing aerated concrete by sequentially supplying to the mixer water, 40-60% surfactant, a siliceous component, cement and plasticizer, mixing the mixture and introducing the remainder of the surfactant, followed by mixing the mixture until complete porosity. Moreover, sulfonate powder or sodium lauryl sulfate in the amount of 0.8-2.0% by weight of cement is used as a surfactant, and C-3 in the amount of 0.2-0.4% by weight of cement is introduced into the mixer as a plasticizer [1 ].

The disadvantage of this method is the weak air intake in the manufacture of cellular concrete products, the heterogeneity of the porous structure of the material obtained, the long mixing time and the introduction of the components of the concrete mixture, as well as the increased consumption of surfactants.

The closest is a method of producing aerated concrete, including the preparation of foam, mixing it with a mixture of binder, filler and a solution of additives. According to the prototype, the mixture is prepared by mechanochemical activation of the binder and filler for 120-600 s followed by mixing for 30-120 s with a solution of additives, and amorphous silica of a fraction of 0.01-1.0 mm in the amount of 25- 60%, and the foam with the resulting mixture is mixed for 20-60 s [2].

The disadvantage of this method is the multi-stage, energy and laboriousness of manufacturing a foam concrete mixture, the instability of the characteristics of the resulting heat-insulating foam concrete with a density of less than 350 kg / m ³ , as well as the increased consumption of a foaming agent (PO).

The technical task is to obtain heat-insulating cellular concrete with a density of less than 350 kg / m ³ with a high-quality porous structure, low density, heat conductivity and shrinkage deformations without reducing its strength, as well as simplifying its manufacturing technology and reducing the consumption of foaming agent.

The problem is solved in such a way that in the method of producing cellular concrete, including mixing the foam with cement and a siliceous component - sand - in the mixer until the mixture is completely porous according to the proposed solution, water is first supplied to the mixer in an amount corresponding to B / T = 0.5- 0.65, sand and a synthetic anionic foaming agent in an amount of 0.08-0.1% by weight of the solid components and mix the components for 1.5-2.3 minutes, then cement is added and the components are mixed until the mixture is completely porous, tv rdye components are added in the following proportions, in weight.%:

sand - 30-35;

cement - 65-70.

An embodiment of the proposed method is the preparation of a foam concrete mixture by mixing foam, a siliceous component and cement until the mixture is completely porous, in which according to the proposed solution, water is first supplied to the mixer in an amount corresponding to W / T = 0.6-0.75 as siliceous the component is introduced perlite fine fraction and a synthetic anionic foaming agent in an amount of 0.08-0.1% by weight of the solid components of the mixture, the components are mixed for 1.5-2.3 minutes, then cement is introduced and then suschestvlyayut stirring until complete porization mixture, the solid components are added in the following proportions, in weight.%:

perlite - 1-3;

cement - 97-99.

Comparative analysis with the prototype shows that the inventive method for producing heat-insulating cellular concrete differs from the known one in that first, water, a siliceous component (fine perlite or sand) are fed into the mixer and synthetic anionic foaming agent is additionally introduced in an amount of 0.08-0.1% based on the weight of the solid components of the mixture, the components are mixed for 1.5-2.3 minutes, then cement is added and then mixed until the mixture is completely porous. In this case, the authors proposed quantitative ratios of solid components. Thus, the claimed technical solution meets the criterion of "novelty."

The use of the above substances in the claimed amounts and changing the sequence of their input into the mixer allows to reduce the density, shrinkage deformation, thermal conductivity of cellular concrete products and to obtain a heat-insulating material with sufficient strength and high-quality porous structure; reduce the consumption of the foaming agent, as well as significantly reduce the time and simplify the manufacturing technology of the foam concrete mixture.

It is known that in the manufacture of foam concrete, synthetic anionic foaming agents act as a blowing agent: they reduce the surface tension at the gas-liquid phase boundary, which leads to the formation of air bubbles and the formation of foam, which is then mineralized.

When implementing this method, the authors first found that when interacting with a siliceous component, the synthetic anionic foaming agent exhibits the properties of a water repellent.

When mixing water, a siliceous component and a foaming agent, taken in the claimed amounts, adsorption of PO molecules on the surface of the siliceous component occurs in the mixer. This allows you to stabilize the uniform fixing of the particles of the component in the foam concrete structure, increase its uniformity and create a skeleton that prevents the strength and shrinkage deformations from decreasing when density is reduced, and therefore the thermal conductivity of the manufactured heat-insulating foam concrete, which is achieved due to more efficient air entrainment at the first stage of solution mixing a foaming agent with a siliceous component. At the same time, the output of the foam-cement mass from the mixer increases, which makes it possible to reduce the amount of the foaming agent used, which, subject to the proposed sequence for introducing the components, additionally hydrophobizes the siliceous component and eliminates the use of special plasticizing additives. This allows us to conclude that the proposed solution meets the criterion of "inventive step".

The proposed method differs from the known sequence of introducing into the mixer components of the cellular concrete mixture, their composition, quantitative ratio and the use of synthetic anionic foaming agents as a water-repellent silica component; a decrease in the number of operations and modes, a lower consumption of a foaming agent per 1 m ³ of cellular concrete products; the possibility of obtaining, when implementing the proposed method, a material with a uniform porous structure, lower density, thermal conductivity and shrinkage deformation without reducing strength. The proposed method is as follows. Portland and slag Portland cement for general construction purposes were used to prepare the cellular concrete mixture, silica components — quartz sand with a particle size modulus of 1-1.5 and fine perlite with a particle size of 0.05 to 0.5 mm, “Penostrom” synthetic anionic foaming agents, and Morphene, the latter were also used as a hydrophobizing agent for the siliceous component.

First, water was supplied to the mixer in an amount corresponding to 100% of the total water volume, and the siliceous component together with the foaming agent in the claimed amount was mixed for 1.5-2.3 minutes, then cement was added and mixed until the mixture was completely porous for 1- 1.5 minutes

For experimental verification of the proposed method for producing heat-insulating cellular concrete, 9 mixtures with sand as a siliceous component and 9 mixtures with perlite were prepared, three for each water-solid ratio.

In example No. 1 for the manufacture of the mixture according to the proposed method, water was supplied to the mixer in an amount corresponding to a water-solid ratio of 0.6, quartz sand with a particle size of 1-1.5 together with a synthetic anionic foaming agent, for example, "Penostrom" in the amount of 0.1 % by weight of the solid components of the mixture was stirred for 2.3 minutes, after which Portland cement PC-500-D0 was added and mixed for another 1.5 minutes until the mixture was completely porous. The amount of cement and siliceous component is 65 and 35%, respectively, of the total mass of the solid components of the mixture.

Table 1
A method of manufacturing a foam concrete (known prototype) №№ Composition characteristics Mixing time min Physical and mechanical properties Cement,% Lime% Sand,% Dry mix Mixtures with a solution Of the whole mass Density, kg / m ³ Strength, MPa The coefficient of thermal conductivity, W / m ² K 1 40 35 25 10 2 0.33 300 0.986 0.08 2 40 - 60 2 05 1 800 4.93 0.17 3 35 - 65 1.8 0.4 0.91 1000 4.93 0.3 4 40 twenty twenty 10.08 2.08 0.4 400 0.986 0.1

table 2
The proposed method of manufacturing foam concrete №№ Composition characteristics Cooking mode Physical and mechanical properties W / T Foaming agent,% of solid components Siliceous component,% Cement,% Duration of mixing water, foaming agent and siliceous component, min The duration of mixing the mixture with cement, min Density, kg / m ³ Strength, MPa The coefficient of thermal conductivity W / m ² · ° C Frost resistance cycle Shrinkage deformation, mm / m Siliceous component - sand 1 0.65 0.1 35 65 2,3 1 222 0.26 0.056 > 25 0.27 2 0.65 0.1 thirty 70 1,5 1 209 0.269 0,053 > 25 0.17 3 0.65 0.08 35 65 2 1 220 0.26 0.056 > 25 0.25 4 0.55 0.1 35 65 2,3 1,5 312 0.419 0,078 > 25 0.1 5 0.55 0.1 thirty 70 1,5 1,5 300 0.377 0,072 > 25 0.12 6 0.55 0.08 35 65 2 1,5 315 0.423 0,079 > 25 0.11 7 0.5 0.1 35 65 2,3 1,5 344 0.513 0,084 > 25 0,07 8 0.5 0.1 thirty 70 1,5 1,5 343 0.509 0,084 > 25 0.09 nine 0.5 0.08 35 65 2 1,5 350 0.515 0,087 > 25 0,07 Siliceous component - perlite 10 0.6 0.1 1 99 1,5 1 275 0.258 0.056 > 25 0.15 eleven 0.6 0.1 1 99 1,5 1 280 0.26 0.056 > 25 0.12 12 0.6 0.08 1 99 1,5 1 300 0.287 0,067 > 25 0.13 thirteen 0.7 0.1 3 97 2,3 1,5 310 0,305 0,068 > 25 0.1 14 0.7 0.1 3 97 2,3 1,5 342 0.343 0,076 > 25 0.08 fifteen 0.7 0.08 3 97 2,3 1,5 346 0.361 0,078 > 25 0.08 16 0.75 0.1 3 97 2 1,5 348 0.349 0,078 > 25 0.09 17 0.75 0.1 3 97 2 1,5 350 0.351 0,079 > 25 0.06 eighteen 0.75 0.08 3 97 2 1,5 349 0.367 0,079 > 25 0.08

Compounds with other parameter values from the selected ranges on the Penostrom foaming agent were made in a similar way; in examples No. 2, 4, 8, 11, 14 and 16 as a synthetic anionic foaming agent was used foaming agent "Morpen".

The characteristics of the compositions, the modes of their preparation and the physicotechnical properties of the resulting heat-insulating cellular concrete are given in Table 2. The properties of materials manufactured by the proposed method were determined in accordance with the requirements of the following regulatory documents: GOST 25485-89, GOST 10180-90, GOST 12730.1-78, GOST 7076-99. The obtained values of the indicators were compared with the characteristics of the material obtained in the implementation of the known method of manufacturing foam concrete shown in Table 1.

As can be seen from the table, the proposed method provides a heat-insulating cellular concrete non-autoclaved hardening with high physical and technical properties.

Thus, the use of the claimed invention allows:

- get heat-insulating cellular concrete with a density of 200-350 kg / m ³ with low shrinkage deformation, without reducing the strength when using a siliceous component in an amount up to 50% by weight of cement;

- reduce the consumption of a foaming agent for the manufacture of insulating cellular concrete;

- use the proposed blowing agents for the hydrophobization of the siliceous component;

- improve air absorption in the foam-cement mixture;

- to improve the structure of the cement matrix in the body of the foam due to a more uniform distribution of pores and particles of the siliceous component;

- improve the thermal insulation properties of foam due to a more uniform distribution of pores throughout the volume of the material;

- increase the resistance of foam concrete in the initial period of time;

- significantly simplify the technology and reduce the production time of the foam concrete mixture;

- increase the output of foam concrete by increasing the output of the foam concrete mixture without additional energy and equipment.

Information sources.

1. RF patent No. 2078749, cl. From 04 to 40/00. BI No. 13, 1997.

2. RF patent No. 2133722, cl. 6 С 04 В38 / 10, 40/00. BI No. 21, 1999.

Claims (2)

1. A method of obtaining a heat-insulating cellular concrete, including mixing the foam with cement and a siliceous component - sand - in the mixer until the mixture is completely porous, characterized in that the water is first supplied to the mixer in an amount corresponding to W / T = 0.5 ÷ 0.65 , sand and inject synthetic anionic foaming agent in the amount of 0.08-0.1% by weight of solid components, mix the components for 1.5-2.3 minutes, then introduce cement and then mix the components until the mixture is completely porous, introducing solid components in the following proportions, in weight.%: Sand 30-35 Cement 65-70 2. A method of obtaining a heat-insulating cellular concrete, comprising mixing the foam, siliceous component and cement in the mixer until the mixture is completely porous, characterized in that water is first supplied to the mixer in an amount corresponding to W / T = 0.6 ÷ 0.75, as the siliceous component is injected with fine perlite and a synthetic anionic blowing agent in an amount of 0.08-0.1% by weight of the solid components of the mixture, the components are mixed for 1.5-2.3 minutes, then the cement is introduced and then the mixture is mixed to full porization minutes the mixture, the solid components are added in the following proportions, in weight.%: Perlite 1-3 Cement 97-99