JPH0624722B2 - Method for manufacturing lightweight foam concrete - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a method for producing lightweight cellular concrete without the risk of cell unevenness occurring at the upper part of a foam layer.

b. Conventional technology Conventionally, lightweight cellular concrete (hereinafter abbreviated as ALC)
Is a slurry added with a foaming agent such as aluminum powder is injected into the mold, foam this slurry in the mold, after demolding,
It was manufactured by cutting to size and steam curing.

c. Problems to be Solved by the Invention In the above conventional manufacturing method, the slurry is not cured for a while even after the foaming is completed, and the slurry is slightly fluid. Therefore, the bubbles of hydrogen gas generated in the slurry tend to gradually move upward due to the floating action. For this reason, the density of the foamed layer after solidification usually tends to be higher on the lower side than on the upper side. As a result, there is a problem in that coarse bubble unevenness is likely to occur in the upper portion of the foam layer due to the concentration of bubbles, and the appearance of the product is impaired.

Furthermore, the air bubbles gather around the reinforcing bar provided inside the ALC plate and form a cavity around it. As a result,
There was also a problem that shadows of the reinforcing bars appeared on the surface of the ALC plate, which further deteriorated the appearance of the product.

d. Means for Solving the Problems The present invention has been made in view of the above problems of the prior art, and its object is to create bubble unevenness in the upper part of the foam layer and a shadow of the reinforcing bar on the surface of the ALC plate. It is to provide a manufacturing method of ALC that can eliminate the fear and improve the quality, and its gist is to inject the slurry containing the foaming agent into the mold to make the slurry into a foamed state. In the method for producing lightweight cellular concrete, a method for producing a lightweight cellular concrete characterized in that a resistor that restricts passage of slurry during foaming is arranged slightly below the upper surface of the foamed slurry. is there.

Specifically, it is a method in which a resistor is previously arranged slightly below the upper surface of the slurry formed at the end of foaming, and then the slurry is foamed in the mold according to a conventional method.

The resistor used in the present invention is a mesh member such as metal lath, expanded metal, welded wire mesh, and a perforated plate such as asbestos slate, plastic, and steel plate.

e. Function During foaming, the slurry during foaming passes through the resistor and tries to form a foamed layer above. However, some of the bubbles moving upward tend to collide with the resistor to form downward convection. As a result, the movement of bubbles caused by the floating action is suppressed, and the unevenness of bubbles generated in the upper portion of the foam layer due to the concentration of bubbles is significantly reduced.

f. Examples Hereinafter, examples in which the ALC manufacturing method according to the present invention is applied to the manufacture of ALC plates will be described.

FIG. 1 is a cross-sectional view showing an ALC plate manufacturing apparatus for carrying out the present invention, which is used in Examples 1 and 3 below.

As shown in the figure, the apparatus 1 includes a curing plate 2 that forms a bottom plate of a tank, a mold 3 that forms the same side plate, a support plate 4 that is disposed above the mold 3 through a support member, and the support. A fixing pin 5 supported by the plate 4 and extending downward; a fixing pin 7 for supporting a rebar cage 6 supported by the fixing 5; a resistor 8 arranged to cover the uppermost rebar cage 6; It is composed of a fixing pin 9 for attaching the resistor 8 to the support plate 4.

The procedure for producing an ALC plate using the above apparatus 1 will be described below.

First, the fixing pin 7 is engaged with the fixing pin 5, and each reinforcing bar cage 6 is fixed to the support plate 4 by the fixing pin 7 in a predetermined arrangement. The figure shows a state in which the reinforcing bar cages 6 are arranged in five layers.

Further, the resistor 8 is attached to the support plate 4 by a fixing pin 9 at a predetermined distance from the uppermost rebar cage 6.

Then, an appropriate amount of the slurry containing the foaming agent is injected into the tank so that the upper surface of the foam layer is formed slightly above the resistor 8. The foaming agent added to the slurry generates hydrogen gas and foams the slurry into about twice the volume. As a result, the upper surface of the slurry is formed at the position shown by the alternate long and short dash line in the figure. When the slurry has hardened to some extent, the mold 3, the fixing pin 7 and the fixing pin 5 are removed, and the slurry is cut to a predetermined size with a piano wire and steam-cured. In each of the following examples, a slurry containing 19 parts of Portland cement, 64 parts of silica stone, 17 parts of quick lime, 65 parts of water, and 0.06 part of aluminum powder as a foaming agent (all parts by weight) was used. In addition, 6 rebar cages are placed in the tank, and 6
ALC plates were made and this process was repeated 3 times to obtain a total of 18 ALC plates.

It is preferable that the interval α between the resistor 8 and the reinforcing bar cage 6 arranged at the uppermost stage is 10 to 200 mm. If this distance is set to 10 mm or less, bubble unevenness showing the pattern of the resistor 8 appears on the surface of the ALC plate, and if it is set to 200 mm or more, the effect of the resistor 8 is diminished.

Example 1. In this example, six layers of rebar cages 6 are horizontally arranged in a tank, and expanded metal XS-33 (SW12 × LW30.5, T2.3 ×) defined as JIS G3351 as low antibody 8 is provided. 3.0) and the interval α
Hold at 50 mm, thickness 100 mm, width 1200 by the above method
An ALC plate with a size of mm and a length of 6 m was manufactured. As a result,
All of the obtained ALC plates had good appearance with no air bubbles and no reinforcement shadows on the surface.

Example 2. In this example, the rebar cage 6 is vertically arranged in the tank,
Expanded metal XS similar to that of the first embodiment as the resistor 8
-33, keeping the spacing α at 60 cm, thickness 100 mm, width
An ALC plate with a size of 600 mm and a length of 6 m was manufactured. As a result, all of the obtained ALC plates had a good appearance without unevenness of cells and shadows of reinforcing bars on the upper surface of the foamed layer as on the lower surface.

Example 3 In this example, the rebar cage 6 is horizontally arranged in the tank,
Punching metal as resistor 8 (diameter 10 mm, pitch 1
2.5 mm, opening area 57.6%), the distance α is kept at 40 mm, and the thickness is 100 mm, the width is 600 mm, and the length is 6 by the above method.
m size ALC board was manufactured. As a result, in all of the obtained ALC plates, the bubble unevenness and the shadow of the reinforcing bar similar to those in the above-mentioned examples were not found.

The following Comparative Examples 1 and 2 were carried out in order to investigate the effect of the resistor 8, and an ALC plate was manufactured under the same conditions as in the above example except that the resistor 8 was not used.

Comparative Example 1. This comparative example is to examine the effect of low antibody 8 in comparison with Example 1 above. The rebar cage 6 was placed horizontally in the tank, and the slurry was foamed without using the resistor 8 to manufacture an ALC plate having the same dimensions as in Example 1 above. As a result, coarse bubbles were found on the upper surface of the foaming tank for 6 of the 18 ALC plates obtained.

Comparative Example 2. This comparative example is to be compared with Example 2 described above. The rebar cage 6 was vertically arranged in the tank, and the slurry was foamed without using the resistor 8 to manufacture an ALC plate having the same size as in Example 2 above. As a result, coarse air bubbles were found on the upper surface of the foaming tank of all the obtained ALC plates.

g. Effect In the present invention, the resistor is arranged slightly below the upper surface of the slurry formed at the end of foaming to foam the slurry, so that one of the slurry during foaming moving upward as the slurry foams. The part collides with the resistor to form downward convection. As a result, the movement of bubbles attempting to float on the upper surface is suppressed and the bubble distribution is made uniform, so that the following effects are achieved.

i) There is no possibility that air bubbles will be uneven in the upper part of the foam layer,
A product with a good appearance is obtained.

ii) It is possible to prevent the shadow of the reinforcing bar, which has been a problem in the manufacturing of ALC plates.

[Brief description of drawings]

FIG. 1 is a sectional view showing an apparatus for manufacturing an ALC plate used in an embodiment of the present invention. 1 ... ALC plate manufacturing device, 2 ... curing plate, 3 ... form frame, 4 ... support plate, 5 ... fixing pin, 6 ... reinforcing bar cage, 7 ... reinforcing bar cage fixing pin, 8 ... resistor body.

Claims (4)

[Claims] 1. A method for producing a lightweight cellular concrete by injecting a slurry to which a foaming agent has been added into a mold to make the slurry in a foamed state, and slightly below the upper surface of the slurry in the foamed state, A method for manufacturing a lightweight cellular concrete, comprising a resistor for restricting passage of slurry during foaming. 2. The method for producing lightweight foam concrete according to claim 1, wherein the resistor is a mesh member. 3. The method for producing lightweight cellular concrete according to claim (2), wherein the mesh member is a metal lath, expanded metal or welded wire mesh. 4. The method for producing a lightweight cellular concrete according to claim 1, wherein the resistor is a perforated plate.