JPH0816036B2 - Method for manufacturing lightweight foam concrete - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a method for producing lightweight cellular concrete using a foaming agent.

[Conventional technology]

In general, lightweight aerated concrete panels are prepared by mixing water with an appropriate ratio of ground siliceous raw materials such as silica sand and silica, and calcareous raw materials such as lime and cement, and adding metallic aluminum powder as a foaming agent to this and stirring. Then, this slurry is poured into a form frame with reinforcing bars vertically set to foam and cut with a cutting device in which wires are stretched in the vertical direction to a desired thickness when it becomes a semi-hardened state. Or, the cake in semi-cured state is rolled 90 ° and cut by a cutting device in which a wire is stretched horizontally, and the product is aged by autoclaving.

When the raw material slurry is foamed using the foaming agent in this way, the depth of the production mold is limited due to the uniformity of the bubbles contained, and the product of about 60 cm is usually used. Lightweight cellular concrete (hereinafter referred to as ALC)) The width of the panel is limited to 60 cm.

In order to manufacture a wider panel than this, after the reinforcing bars are horizontally held in the mold and the raw material slurry is poured and foamed and semi-cured, this is cut horizontally to a desired thickness. Alternatively, it is necessary to form a single sheet with a mold having a desired depth. However, since the movement of the raw material slurry due to foaming swells from the bottom to the top, the portion directly above the reinforced reinforcing bars placed may not be sufficiently filled with foam, and when the reinforced reinforcing bars are mainly placed horizontally. Indicates that the reinforcing bars are present on the same vertical surface with short pitches, and as a result, the filling of the foam directly above the reinforcing bars is incomplete, there are many opportunities for air bubbles to be disturbed, and the flat surface in the thickness direction of the panel from the reinforcing bars. Since the distance to is small, the effect of incomplete filling right above the rebar easily appears on the panel surface, and continuous air bubbles appear on the product surface, causing a decrease in the bond strength between the rebar and concrete, which affects the panel strength itself. Also has a serious impact.

On the other hand, when the reinforcing bars are arranged mainly in the vertical direction in the formwork, the reinforcing bar pitch in the same vertical plane is large, so there is almost no problem due to the small reinforcing bar pitch, and the distance from the reinforcing bar to the panel side is also thick. Since it is larger than the distance in the direction, the appearance of the panel was not spoiled.

Therefore, when reinforced reinforcing bars are placed horizontally in the form, as in the case of manufacturing wide panels, foam is contained by using a foaming agent without using a foaming agent such as aluminum powder. The method of adjusting the slurry of the concrete material and using this was adopted.

That is, air is blown into an aqueous solution containing a foaming agent to generate bubbles, and the required amount of this foam is mixed into a slurry in which cement and other materials are mixed, or an aqueous solution containing a foaming agent and cement or other Mix the slurry containing the materials, blow the required amount of air into it to adjust the concrete material slurry containing the air bubbles, pour this into the mold to semi-harden it, and then cut it if necessary. The product was cured by high temperature and high pressure steam in an autoclave.

If the concrete material slurry containing bubbles is injected into the form using a foaming agent, the above-mentioned problems associated with foaming are solved, but the foaming agent has a small foam size, When the size is small, it takes more time for steam to reach the center of the material during high temperature and high pressure curing in an autoclave than when using a foaming agent such as aluminum. Not only does it take a long time, but sometimes it causes an explosion and partially creates a hollow portion, resulting in a poor product yield, a slightly insufficient compressive strength of the product, large water absorption, and other problems. Atsuta

[Problems to be solved by the invention]

The present invention provides a method for producing lightweight cellular concrete using a foaming agent that solves the above problems.

[Means for solving problems]

In order to achieve this object, the present invention slightly reduces the amount of foam contained by a foaming agent, and adds a small amount of aluminum as a foaming agent to a concrete slurry for foaming. The aluminum powder is added so that the volume of the bubbles generated by 15 to 50% of the volume of all the bubbles contained in the lightweight cellular concrete.

If the volume of bubbles generated by aluminum is 15% or less of the ratio of the total volume of bubbles, the effect of improving properties by adding aluminum is insufficient, and if it exceeds 50%, the reinforcing bar described in the prior art is not used. It should be avoided as it has drawbacks when placed horizontally and foamed with aluminum.

The foaming agent used may be potassium salt of succinic acid, maleated resin, sulfate of higher alcohol, partial hydrolyzate of animal protein, ether type nonionic surfactant containing polyoxyethylene group, etc., Among them, in particular, a partial hydrolyzate of animal protein or the inventors of the present invention has disclosed Japanese Patent Application No. 60-24.
It is preferable to use a mixture of the alkanolamide-type nonionic surfactant applied for in No. 3707 and the ether-type nonionic surfactant containing a polyoxyethylene group because the bubble stability is high and the toughness is strong.

The amount of these surfactants used varies depending on the cement in the concrete material, the type and mixing ratio of the binder or the extender, the desired bulk specific gravity of the lightweight cellular concrete, the amount of kneading water, etc., and cannot be uniformly defined, Usually, it is preferably used in an amount of 0.05% by weight or more, more preferably 0.07 to 0.8% by weight, based on the kneading water.

The amount of aluminum powder used varies depending on the bulk specific gravity of the intended product, but for example, in the case of a product having a bulk specific gravity of 0.5, it is about 0.01 to 0.04% by weight based on the weight of the solid content of the raw material.

In carrying out the present invention, after preliminarily foaming an aqueous solution containing a foaming agent by means such as stirring or aeration, a pre-ohming method in which this is mixed with a concrete material slurry to include bubbles, There is a mixing foaming method in which air bubbles are included in the slurry when mixing an aqueous solution containing a foaming agent and a concrete material, and either method can be adopted, but it is easy to obtain a homogeneous foam content in the operation in the factory. The preformation method is advantageous in that point.

Cement, which is a raw material for lightweight cellular concrete, may be only cement as other material, but usually, as a material other than cement, for example, silica stone, silica sand, lime, granulated blast furnace slag, gypsum, in the production process of sand and products. The generated waste is used. Of course, it is not always necessary to use all of them, and it suffices to select an arbitrary component, and if necessary, other materials can be used.

[Action]

According to the present invention, among the bubbles contained in the lightweight cellular concrete, since some of them include those foamed by aluminum, the foam generated by this aluminum is larger than the foam by the foaming agent and The size of the bubbles is also non-uniform, and the bubbles are dispersed almost evenly throughout the small bubbles due to the foaming agent, so the vapor penetrates well inside the autoclave during curing and prevents phenomena such as explosion. ,
In addition, since the amount of bubbles due to foaming of aluminum is half or less than that in the case of generating bubbles due to only aluminum, the problem of insufficient filling directly above the reinforcing bar due to foaming hardly becomes a problem, and the compressive strength is also low. A satisfactory value can appear.

〔Example〕

 Examples will be described below.

Example 1 A foaming agent was used to prepare an aqueous solution prepared by diluting 20 times the amount of Foamix C ₂ (trade name: manufactured by Hamano Industry Co., Ltd.) containing a partial hydrolyzate of animal protein as the main component, and preparing the foaming machine. Create bubbles through.

On the other hand, 29 parts by weight of silica, 20 parts by weight of cement, 5 parts by weight of quick lime, 5 parts by weight of gypsum, and 0.01 to 0.036 parts by weight of aluminum powder as a foaming agent are added to 41 parts by weight of water and mixed with stirring to obtain a concrete material. A slurry was prepared, and the above-mentioned cells were mixed in such an amount that the amount of the cells contained in the lightweight cellular concrete having a bulk specific gravity of 0.5 was 85 to 50% of the total volume of the cells, and no aluminum powder was used as a comparative example, or Add more aluminum powder or mix no air bubbles at all, and adjust the volume of the air bubbles by the foaming agent to 100% of the total air bubbles or 50% or less to 0%, and adjust this slurry to a width of 1200 mm and length. In the flat form of 2400mm, depth 125mm,
As a reinforcing bar for the panel, 5.5 mm diameter rebar was welded in a cage shape by welding 5 vertical bars on the tension side and 3 vertical bars on the compression side, and 5 horizontal bars intersecting this, and poured them. . After standing for 4 hours, the surface was scraped to a thickness of 100 mm, and autoclave curing was carried out by a conventional method. After autoclave curing, the test piece was cut out according to the appearance inspection and JIS A 5416,7 and the compressive strength was measured. The bulk specific gravity of the obtained product is 0.5 ± 0.03, and the values of compressive strength are shown in Table 1 after correcting the specific gravity to 0.5.

As shown in the table above, the test No. 1 to 4 with the aluminum powder having a foam ratio of 100 to 60% has a continuous hollow portion immediately above the reinforcing bar, and the appearance of the panel surface is also affected. The durability of the panel will be poor. Test No. 8
Most of the aluminum powders that do not use aluminum powder have a bubble diameter of 1 mm or less and are very fine, and the penetration of steam during autoclave curing was poor, and numerous cracks entered during decompression, and the cracks developed and were destroyed. On the other hand, the foam ratio of aluminum powder of Test Nos. 5 to 7 corresponding to the example is 15 to
The one with 50% had no blasting, had a good surface condition, and had a satisfactory compressive strength value. No. 7 had a slight crack on the surface, which was practically acceptable.

Example 2 Amizole CDE (trade name: manufactured by Kawaken Fine Chemicals Co., Ltd.), which is an alkanolamide-type nonionic surfactant as a foaming agent, and Emulgen 120 (which is an ether-type nonionic surfactant containing a polyoxyethylene group, (Product name: made by Kao) was mixed at a weight ratio of 6: 4 to prepare a 3% by weight aqueous solution, and this was bubbled through a foaming machine. On the other hand, silica 25
Parts by weight, cement 23 parts by weight, quick lime 4 parts by weight, gypsum 5 parts by weight and the necessary amount of aluminum powder as a foaming agent are added to 43 parts by weight of water and mixed by stirring to prepare a concrete material slurry, and the above-mentioned bubbles Was mixed in an amount of 30 to 100% of the volume of all bubbles contained in lightweight cellular concrete having a bulk specific gravity of 0.5. Width 1800 mm, length 2400
Welded reinforcing bars of 5.5 mm in diameter as reinforcing bars for panels in a flat plate form with a depth of mm and a depth of 125 mm by welding 7 reinforcements on the pulling side, 4 vertical reinforcements on the compression side, and 5 transverse reinforcements intersecting them. A basket-shaped product was arranged and poured, and a panel was obtained according to the method described in Example 1 below and tested. The results are shown in Table 2.

As shown in the above table, the test Nos. 11 to 13 in the range of the present invention had no explosion, good surface condition and satisfactory compressive strength. However, the test No. 14 that does not use aluminum at all does not cause explosion when the foaming agent of this example is used and the surface condition is good, but the compressive strength is a little inferior, and there is much foam due to aluminum. In Nos. 9 and 10 containing only bubbles of aluminum, the same defects as those described in Example 1 appeared.

〔The invention's effect〕

As described in detail above, according to the method of the present invention, as in the case of manufacturing a wide lightweight lightweight concrete panel, the reinforcing bars are arranged vertically with short pitches, and are formed by a foaming agent such as aluminum. A lightweight cellular concrete that is used when partially swelling the raw material slurry and covers the shortcomings of the raw material slurry that contains air bubbles with a foaming agent and supplements the advantages of the foaming agent and has good strength. Can be manufactured.

Claims (3)

[Claims] 1. A concrete material slurry containing air bubbles is prepared by mixing an aqueous solution containing a foaming agent before or after foaming the mixture, and mixing the aqueous solution with a concrete material composed of cement and another material. In a method for producing a lightweight cellular concrete by pouring the slurry into a mold, molding and curing, aluminum powder is added to a concrete material as a foaming agent, and the volume of bubbles produced by aluminum is in the lightweight cellular concrete. A method for producing a lightweight cellular concrete, which comprises adding aluminum powder so as to be 15 to 50% of the volume of all the cells contained in. 2. The method for producing a lightweight cellular concrete according to claim 1, wherein the foaming agent is a partial hydrolyzate of animal protein. 3. The method for producing a lightweight cellular concrete according to claim 1, wherein the foaming agent is a mixture of an alkanolamide type nonionic surfactant and an ether type nonionic surfactant.