JPS6385072A - Manufacture of lightweight foamed concrete products - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to lightweight aerated concrete products used for wide S-wall applications such as exterior wall materials, interior wall materials, floor materials, ceiling materials, heat insulation materials, sound insulation materials, and sound absorption materials. This relates to a manufacturing method.

[Background technology] In recent years, the use of dry method 1 has been increasing in manufacturing concrete molded products, especially building materials, etc. Among them, lightweight aerated concrete products are manufactured using ALC (Autoclave method).
ved Li) Htweight Concrete
) is extremely useful as a building material, but it has high water absorption and its insulation properties are seriously reduced, and moreover, it loses moisture in winter environments in cold regions. The current situation is that it has many defects in that it freezes and breaks or cracks due to volumetric expansion, which greatly limits its use.

In terms of manufacturing methods for lightweight aerated concrete products, there are two methods: the post 7 ohm method and the preform method. The post 7-ohm method is a method in which a cement composition such as a cement paste containing a foaming agent is injected into a mold and then foamed, and most ALCs are manufactured by this method. On the other hand, in the preform method, foam created in advance using a foaming agent and a foam stabilizer is mixed into a cement composition such as cement paste, and the cement composition mixed with the foam is injected into a mold and hardened. This preform method, in which foam is created in advance, has the advantage of being able to form lightweight cellular concrete products having a desired cross-sectional shape. However, when manufacturing lightweight cellular concrete products using the preform method, it takes a long time for the cement to harden when molding is carried out at room temperature, and care must be taken to prevent the destruction of bubbles and foam during this hardening time. Handling is required and manufacturing efficiency is reduced. Therefore, after pouring into the mold, the cement is heated to make it harden quickly, but this heating causes the bubbles to expand and connect with each other, forming open cells. Water absorption by open cells may reduce insulation performance, breakage or cracks may occur due to freezing in cold regions, and furthermore, the product may deteriorate due to expansion and breakage of the bubbles. It was something that I had.

[Object of the Invention] The present invention has been made in view of the above points, and provides a method for manufacturing lightweight cellular concrete products that can be manufactured using a preform method without turning closed cells into open cells. The purpose is to

[Disclosure 1 of the Invention] The method for producing a lightweight cellular concrete product according to the present invention includes mixing foam previously created with a foaming agent into a cement composition that is made of cement e as a main component and kneaded with water. Create lightweight aerated concrete using the preform method, which molds and hardens the cement composition mixed with this foam! l! When leaving, the cement composition and the foam are each
The present invention is characterized in that it is mixed and molded and cured while being maintained at 80°C.The present invention will be described in detail below.

Cement compositions are mainly composed of hydraulic cement, which is mixed with aggregates and kneaded with water (1) to prepare cement slurry or cement paste, and is commonly used as hydraulic cement. Portland cement, white cement, alumina cement, jet cement, gypsum, blast furnace slag, etc. can be used alone or in combination of two or more. In addition, as aggregates, silica sand, silica stone powder, plyash, silica 7 laur, calcium carbonate, etc. can be used alone or in combination of two or more, but especially for applications that require heat resistance. It is preferable to use heat-resistant aggregates such as shelben and chamotte. Here, the mixing ratio of hydraulic cement and aggregate is generally in the range of 80,720 to 20/80 by weight.

Further, it is preferable to add a foam stabilizer to the cement composition in order to stabilize the foam to be mixed, which will be described later.

The foam stabilizer may be added to the cement composition before introducing the foam, or it may be added to the cement composition after the foam is introduced. In order to obtain the effect of stability and water absorption reduction of the molded lightweight cellular cement product, it is preferable that the foam stabilizer be incorporated into the cement composition in advance before introducing the foam. This foam stabilizer consists of asphalt emulsion marnosin, vinyl acetate emulsion, etc.
Alternatively, two or more types can be used in combination, and the blending amount is preferably 1.5 to 50% by weight, particularly 2 to 15% by weight. If necessary, a water reducing agent such as lignin sulfonate, β-naphthalate, or formalin condensate is added to the cement composition in an amount of 1% or less in double weight to adjust the fluidity of the cement composition. You can also do that.

Foam is created by mixing a foaming agent with water and introducing it together with compressed air into a closed cell generation processor and passing it through. Foaming agents include protein-based, nonionic-based, amphoteric-based, Each foaming agent such as a polymeric polyvalent metal salt can be used alone or in combination of two or more. When creating foam in this way, it is preferable to use water-soluble polymers in combination for thickening, and examples of water-soluble polymers include polyvinyl alcohol (PVA), hydroxypropylmethylcellulose (HPMC), and hydroxyethylcellulose. (HEC), methyl cellulose (MC)
, polyvinylpyrrolidone, pullulan, etc. can be used alone or in combination of two or more.

In this foam generation system, the amount of foaming agent blended is 0.001~
5% by weight, the amount of water-soluble polymer blended is 0.01-1% by weight
It is preferable to set the bubbles in the range of 40 to 8.
Viscosity at 0℃ is 1QQOOcps or more, density is 0.03
-0.08g/cm'I: It is preferable to set it so that it is adjusted to W.

However, as mentioned above! ! l! 4 cement compositions and foams created as uniform fine closed cells, respectively.
The cement composition is heated in advance to a temperature of 0 to 80°C, and while maintaining this temperature, foam is supplied to the cement composition and stirred and kneaded to make the cement composition contain foam. The amount of foam added to the cement composition is preferably such that the air content is 40 to 200% by volume.

Then, while maintaining this temperature, the cement composition is injected into the mold and hardened to obtain a lightweight cellular concrete product. Here, since the cement composition containing foam is molded while being heated and maintained at a temperature of 40 to 80°C, curing proceeds quickly and production efficiency can be increased. is 40 to 80 before molding
Since the cement composition is heated to a temperature of 40 to 80 degrees Celsius, the bubbles are not expanded when the cement composition is molded and hardened at a heating temperature of 40 to 80 degrees Celsius. This means that lightweight cellular concrete products can be manufactured without the risk of forming open cells.

In addition, since the foam is not subject to large temperature changes and does not expand during molding and hardening, it is possible to obtain a lightweight cellular cement product with a specific gravity that corresponds to the foam content in the cement composition. It is possible to obtain a lightweight cellular cement product with the desired specific gravity. In addition, the heating temperature is 40℃
If it is less than 80°C, the curing speed of the cement composition cannot be sufficiently increased, and even if the heating temperature exceeds 80°C, the curing speed of the cement composition cannot be increased any more and the energy It becomes economically uneconomical and the stability of the foam decreases. Therefore, in the present invention, the heating temperature of the cement composition and foam is limited to a range of 40 to 80°C.

Next, the present invention will be specifically explained with reference to Examples.

80 parts by weight of ordinary Portland cement, 20 parts by weight of jet cement, 2 parts by weight of gypsum, 40 parts of silica sand (No. 8)
A cement composition heated to 65° C. was prepared by stirring and mixing a mixture of 7,324 parts by weight of asphalt emul, and 30 parts by weight of water using a heated mixer. On the other hand, water, a protein-based foaming agent, and methyl cellulose were sealed in a pressure vessel heated to 65°C at a weight ratio of 20:1:0.1, and compressed air was injected into the pressure vessel. Uniform fine closed-cell foam heated to 65°C and having a density of 0.04 g/em3 was produced from the nozzle. Next, foam is injected into the cement composition and mixed until the density of the cement composition becomes 0.42 g/am'.
This foam-containing cement composition is poured into a mold, and 6
The foam was cured while maintaining the temperature at 5° C. for 1 hour to obtain a foamed cured product. By curing this, the density becomes 0,31
A lightweight cellular concrete product of g/am' was obtained.

Scale 1" [L Add bubbles to the cement composition. The density of the cement composition is 0.75.
A lightweight aerated concrete product having a density of 0.62 g/ca+' was obtained in the same manner as in Example 1, except that the injection was carried out until it reached g/am'.

By stirring and mixing a mixture of 80 parts by weight of K19 ordinary Portland cement, 20 parts by weight of high alumina cement, 40 parts by weight of ply ash, 5 parts by weight of asphalt emulsion, and 1 part by weight of 30 parts of water using a heated mixer. 50
The cement composition heated to ℃ i4! It's l. On the other hand, water, a protein-based foaming agent, and polyvinyl alcohol are sealed in a pressure vessel heated to 50°C at a weight ratio of 20:1:0.2, and compressed air is injected into the pressure vessel. 5 with a density of 0,05 g/cm' from the nozzle
0, which created uniform fine closed-cell foam heated to 0°C.
Next, add bubbles to the cement composition until the density of the cement composition is 0.
, 9 g/cm' and mixed, and the cement composition containing this foam was poured into a mold and cured while maintaining the temperature of 50°C for 40 minutes to obtain a foamed hardened product. Ta. By curing this, the density becomes 0.81g/c+
*A lightweight aerated concrete product was obtained.

A cement composition having the same composition as in Example 1 was heated at room temperature (20 to 2
The mixture was prepared by stirring and mixing with a mixer under conditions (5°C). In addition, water, a protein-based foaming agent, and methylcellulose are sealed in a pressure vessel at a weight ratio of 2o:i:o,os at room temperature, and compressed air is injected into the pressure vessel through the nozzle of the pressure vessel. Density is 0.045g/cm'
Created uniform fine closed-cell foam. Next, foam is added to the cement composition until the density of the cement composition is 0, 85 g/
cm' and mixed, the cement composition containing this foam was poured into a mold, left at room temperature for 6 hours, and then heated to 80°C at a temperature increase rate of 1°C/min. This temperature was maintained for 10 hours to obtain a foam cured product. By curing this, a lightweight cellular concrete product with a density of 0.72 g/cm' was obtained.

The water absorption rates of the lightweight cellular concrete products obtained in Examples 1 to 3 and Comparative Example were measured, and the results are shown in the table below.

The results shown in the table above confirm that the water absorption rate of each example was low and that a lightweight cellular concrete product was formed by closed cells.

[Effects of the Invention] As described above, in the present invention, the cement composition and the foam are mixed and molded and hardened while each being maintained at a temperature of 40 to 80°C. It is possible to quickly cure the product while heating it to a temperature of 40 to 80 degrees Celsius, increasing manufacturing efficiency. It is possible to manufacture lightweight aerated concrete products without the risk of forming open cells due to the expansion of the foam. This prevents the insulation performance from deteriorating in cold climates or from breaking or cracking due to freezing in cold regions.

Claims (1)

[Claims] (1) Light-weight foam is created by the preform method, in which foam created in advance with a foaming agent is mixed with a cement composition prepared by mixing cement with water as the main component, and the cement composition mixed with this foam is molded and hardened. A method for producing a lightweight cellular concrete product, which comprises mixing a cement composition and foam while maintaining each at a temperature of 40 to 80°C, and molding and hardening the mixture in producing concrete.