RU2406711C1 - Method of producing reinforced cellular-concrete mix - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to construction, namely, to methods of producing reinforced cellular-concrete mix. Proposed method comprises separate foam formation using foam-forming agent, water, liquid glass, making cement solution from water cement, sand and polyamide fiber in baromixer. Foam and cement mix are prepared simultaneously. Water solution of foam-forming agent with liquid glass are prepared in separate vessel as components are fed in the following sequence: liquid glass, foam-forming agent and water. 5%-water solution of foam-forming agent is fed in foam aeration system. Compressed air is forced through said system at 5-6 atm to produce high expansion foam to be forced in working baromixer that doubles as an injector. After required volume of foam uniformly distributed in cement-sand solution is fed, pressure in baromixer increases to 1.5-2 atm. Now, pressure in baromixer is abruptly reduces. Compressed air in the form of bubbles breaks polyamide finer in single threads to distribute it uniformly over the entire mix.

EFFECT: reduced time of preparing reinforced cellular concrete mix, reduced consumption of binder and foam-forming agent.

1 dwg, 2 tbl

Description

The invention relates to the field of building materials industry and can be used to obtain products from non-autoclaved reinforced cellular concrete both in a factory and at a construction site.

Known methods for the manufacture of foam concrete products, including the separate preparation of cement-sand mortar and foam with their subsequent mixing (French Patent No. 78116821, publ. 28.12.79 g.; Patent RU No. 2139268, publ. 10.10.99 g .; Patent RU No. 2136634 publ. 10.09.99).

A disadvantage of the known methods is the multicomponent composition, various chemical compounds are used as additives, two mixers are used, as a result, the duration of the mixture production cycle is increased, which complicates the production of blocks in industrial volumes, and the mixture is obtained as a result of simple mixing, which leads to porous inhomogeneity , respectively, the equal strength of the product is not achieved.

A known method of preparing foam concrete products, including the simultaneous preparation of a cement-sand mixture and foam in one mixer with the addition of polyamide fiber (Patent RU No. 2132315, publ. 06/27/99, Patent RU No. 2226517, publ. 10.04.2004).

A disadvantage of the known methods is that the mixing of the foam and the cement-sand mixture with the addition of polyamide fiber occurs in a single mixer, this does not achieve equal strength of the product and the uniformity of dispersed reinforcement with polyamide fiber is not ensured. In the finished product there will be sections of voids and clumping of fibers.

The closest in technical essence and the achieved effect is a method of obtaining a raw material mixture for the manufacture of non-autoclaved foam concrete (Patent No. 2197451, publ. 01/27/2003), including separate preparation of foam from a foaming agent, water and cement hardening accelerator, introducing a polymer modifying additive into the foam , preparation of a cement mortar from cement, aggregate, fibrous filler, additives - initiator and accelerator of curing polymer and water, the activation of the specified solution and subsequent mixing p vene and cement mortar, and the raw mixture contains components in the following ratio, wt.%: cement 35-65, aggregate 0-30, fiber filler 0-8, cement hardening accelerator 0.3-1.6, foaming agent 0.4- 0.85, polymer modifying additive 0.5-10.0, polymer curing initiator 0.15-0.30, polymer curing accelerator 0.2-3.5, water - the rest. In this case, sodium salts of secondary alkyl sulfates or alkyldimethylamine oxide are used as a foaming agent, as an accelerator for hardening of alkali metal salts of potassium sulfate or sodium, or sodium fluoride, or sodium silicofluoride, acrylic emulsions of styrene, acrylic and methacrylic monomers are used as a modifying additive, esters of acrylic and methacrylic acids in proportion to the curing initiator 1: (0.15-0.3 5), and the specified additive is administered in an amount of not more than 5 wt.% dry matter CTBA initiated curing acrylic copolymer is a solution of sodium or potassium methylsiliconate and their curing accelerator - lime or sodium water glass.

The disadvantage of the prototype is the complexity of the process of preparing a multicomponent mixture, a lot of chemical additives, the duration of the preparation of the mixture, since time is spent on the phased introduction of chemical additives and the activation of the cement in a separate rotary type activator.

The objective of the utility model is to simplify the process of obtaining a reinforced cellular concrete mixture by reducing the time of its preparation.

The technical result consists in increasing the uniformity of dispersed reinforcement and, as a result, increasing the equal strength of the product.

The technical result is achieved in that a method for producing a reinforced cellular concrete mixture, comprising separately preparing foam from a foaming agent, water, water glass, preparing a cement mortar from water, cement, sand, polyamide fiber in a bar mixer, the foam and cement mortar being prepared simultaneously, while an aqueous solution of a foaming agent with liquid glass is prepared in a separate container in the process of receipt of the components in the following sequence: liquid glass, foam atelier, water and fed into the foam aeration system, the prepared 5% aqueous foaming agent solution and compressed air pass through the foam aeration system at a pressure of 5-6 atm and form a high-pressure foam, which is pumped with excess air into the working mixer as an injector, after the required volume of foam is received , evenly distributed in the cement-sand mortar, a pressure of 1.5-2 atm is formed in the bar mixer, then a sharp pressure drop occurs in the bar mixer, compressed air, in the form of bubbles, breaks the polyamide into locally on single threads and distributes it evenly throughout the mass of the resulting mixture.

The drawing shows the installation diagram for implementing the method.

The installation consists of a mixer 1, a foam aeration system 2, valve 3, a container for preparing an aqueous solution of a foaming agent 4.

The method is implemented as follows.

The method of obtaining a reinforced cellular concrete mixture includes the preparation of foam and cement mortar at the same time.

In the container 4, an aqueous solution of a foaming agent with liquid glass is prepared, the proposed sequence of introducing the components, namely, liquid glass, foaming agent, water, allows to obtain a homogeneous solution, and mixing the solution until uniform occurs during the period of receipt of these substances in the specified sequence. At the same time, doses of raw materials consisting of water, cement, sand, 40-60 mm polyamide fiber with constant stirring are loaded into the mixer 1 with a volume of V = 2 m ³ , with a system inside the opposite augers. From the tank 4, an aqueous 5% solution of a foaming agent with liquid glass and compressed air pass through the foam aeration system, forming a high-pressure foam, which is pumped with excess air at a pressure of 5-6 atm into the mixer 1, where the solution continues to mix from below as an injector. After the required amount of foam is released, a pressure of 1.5-2 atm is formed in the mixer with a sharp pressure drop through valve 3, before that the previously mixed foam is evenly distributed in the cement-sand mortar, and the excess air, in the form of bubbles, breaks the polyamide fiber into thin single threads and evenly distributes it over the entire mass of the resulting mixture. Fast and uniform flow from the bottom up of the finished foam with a uniform and uniform distribution of bubble inclusions in a heavy solution can significantly improve the strength characteristics of the finished blocks. In parallel with this, when the foam-air mixture with excess air is supplied, a uniform distribution of the polyamide fiber in the solution occurs, which is a reliable reinforcement and subsequently eliminates the cracking mechanism in the finished blocks. The time to prepare one batch V = 2 m ³ is 6-10 minutes.

After preparing the mixture through the discharge device, the mixture is forced out of the mixer and poured into molds.

To prepare a reinforced cellular concrete mixture use:

- liquid sodium glass GOST 13078-81;

- polyamide fiber, chopped 40-60 mm TU 6-13-53578992-78;

- synthetic foaming agent PB-2000;

- cement 500DO;

- sand with a particle size modulus of up to 0.4 mm not less than 80% in the composition, with a content of silty and loamy not more than 1%;

- water.

Examples of physico-technical properties of the reinforced cellular mixture are given in table 1, table 2.

The proposed method can significantly reduce the preparation time of the reinforced cellular concrete mixture per cycle. The proposed method can significantly reduce the consumption of binder in relation to aggregates, up to 50% binder to 45% aggregate, and reduce the consumption of foaming agent to 300 g per 1 m ³ . The proposed method allows to obtain reinforced cellular concrete of increased strength with high thermal insulation properties, due to the uniform distribution of polyamide fiber and bubble inclusions.

Table 1 No. p / p Parameter Name Units rev. Standard values in accordance with GOST 25485-89 Actual value one Density in the dried state, Brand kg / m ³ 631 D 600 D 600 2 Compressive Strength, Grade MPa 2.0 25.1 IN 2 3 Frost resistance cycle fifteen fifteen four Drying Shrinkage mm / m No more than 3.0 1.8 5 Release humidity % No more than 25 12.8 6 The coefficient of thermal conductivity in the dry state, λ W / m ° C 0.14 0.138 7 Thermal conductivity at W = 8% W / m ° C 0.138 8 Thermal conductivity at W = 15% W / m ° C 0.2271 9 The coefficient of vapor permeability, µ mg / (m · h · Pa) 0.14 0.12

table 2 No. p / p Parameter Name Units rev. Standard values according to GOST 25485-89 Actual value one Density in the dried state, Brand kg / m ³ 795 D 800 D 800 2 Compressive Strength, Grade MPa 330 2.5 At 2.5 3 Frost resistance cycle fifteen fifteen four Drying Shrinkage mm / m No more than 3.0 1.8 5 Release humidity % No more than 25 12.8 6 The coefficient of thermal conductivity in the dry state, λ W / m ° C 0.252 0.212

7 Thermal conductivity at W = 8% W / m ° C 0.291 8 Thermal conductivity at W = 15% W / m ° C 0.3524 9 The coefficient of vapor permeability, µ mg / (m · h · Pa) 0.14 0.12

The tables show that the physical characteristics of the products obtained by the proposed method correspond to GOST.

Claims (1)

A method of obtaining a reinforced cellular concrete mixture, comprising separately preparing foam from a foaming agent, water, water glass, preparing a cement mortar from water, cement, sand, polyamide fiber in a bar mixer, characterized in that the preparation of foam and cement mortar occurs simultaneously, while the aqueous solution of the foaming agent with liquid glass is prepared in a separate container in the process of receipt of the components in the following sequence: liquid glass, foaming agent, water and served in systems in the case of foam aeration, the prepared 5% aqueous solution of the foaming agent and compressed air pass through the foam aeration system at a pressure of 5-6 atm and form a high-foam foam, which is pumped with excess air into the working mixer as an injector, after the required volume of foam is uniformly distributed into cement-sand mortar, a pressure of 1.5-2 atm is formed in the bar mixer, then a sharp pressure drop occurs in the bar mixer, compressed air, in the form of bubbles, breaks the polyamide fiber into single strands and p spredelyaet it evenly across the bulk mixture.