JPS6411594B2 - - Google Patents

Description

[Detailed description of the invention] Purpose of the invention (industrial application field) The present invention is directed to lightweight aerated concrete (hereinafter referred to as ALC).
The present invention relates to a method for producing an ALC precursor molded body, which is a precursor of a molded body (called ALC).

(Prior art) Generally, as a method for manufacturing an ALC molded body,
A process of mixing water with powdered raw materials for ALC production, such as silica sand, quicklime, cement, and aluminum powder, to obtain a slurry-like raw material, and molding the slurry-like raw material obtained in this process to form a semi-hardened large cake. A step of demolding the large cake obtained in the step, and then causing a reciprocating wire to cross or longitudinally cross the demolded large cake in a direction substantially perpendicular to the direction of the reciprocating motion. A method comprising a step of obtaining an ALC precursor molded body by using the same method, and a step of curing the ALC precursor molded body in an autoclave is conventionally well known.

Since the ALC molded body obtained by this method is used for external wall materials of buildings, etc., the surface cut by the wire (hereinafter referred to as the cut surface) is smooth and has a certain degree of surface strength. However, if the large cake is cut with a wire without special efforts, there is a problem that the cut surface will be rough.

Therefore, the present application focused on the hardness of the ALC precursor molded body and developed and proposed a technology that can significantly improve the above problem by imparting a specific motion to the wire (Japanese Patent Application Laid-Open No. 48−34927
Publication No.).

(Problems to be Solved by the Invention) However, it has since been found that this method still has room for improvement in the following points.

First, since the hardness of the ALC precursor molded body changes depending on the composition of its powdery raw material, the composition must be kept within a specific range.

Second, when the slurry raw material obtained from the powdered raw material and water is molded into a large cake using a mold and then removed from the mold, the large cake hardens over time, and as it hardens, the compressive stress suddenly increases. The fact is that it will grow. For example, if we examine the relationship between the compressive stress and strain of a large cake over time after preparing a slurry-like raw material, we will see the behavior shown in Figure 2.

That is, after preparing the slurry raw materials, for 1 hour,
When we plot the relationship between compressive stress σ and strain ε of the large cake after 2 hours, 3 hours, 4 hours, and 6 hours, we get the following curves, respectively.
The relationship curves are as shown in and, and the maximum compressive stress increases rapidly with the passage of time.

On the other hand, although the hardness of large cakes increases with time, its behavior changes approximately linearly, as shown in Figure 1, and is not necessarily completely 1:1 with the maximum compressive stress.
does not correspond to This is thought to be due to the fact that in large cakes with a cross section of 150 x 70 cm, the hardness of the surface side and the hardness of the center side change independently. It will be done.
Naturally, the roughness of the cut surface of the large cake differs depending on the maximum compressive stress.

Therefore, if the cutting timing of a large cake is set based only on the hardness of the large cake, an ALC molded body with a smooth cut surface and high surface strength cannot be obtained in the end. especially,
Changes in outside temperature tend to cause variations in the hardness of the surface side and the center side, so even if the hardness is in the same range, the way the wire cuts a large cake may vary slightly, and in some cases Breakage of the wire itself occurs, and even if breakage does not occur, the smoothness and surface hardness of the cut surface of the resulting large cake change.

Therefore, it is necessary to determine the timing of cutting the large cake so that a smooth cut surface with high surface strength can be obtained in the process where the compressive strength of the large cake changes moment by moment after demolding.

Therefore, an object of the present invention is to find the above-mentioned cutting timing, and to make the cutting surface smooth and strong.
The objective is to obtain a precursor molded body for producing an ALC molded body.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention includes (a) 40 to 80% by weight of silica sand, 5 to 25% by weight of quicklime, 5 to 40% by weight of cement, Consisting of 0.5-10% by weight of gypsum and 0.05-0.125% by weight of aluminum powder,
A step of mixing 40 to 80% by weight of water based on the total weight of powdered raw materials for producing lightweight cellular concrete, the total of which is 100% by weight, to obtain a slurry-like raw material; (b) obtained in the step; (c) forming the large cake obtained in this step into a semi-hardened large cake with a hardness of 150 to
400g/ ^cm2 and maximum compressive strength 0.15-2.0
When the physical properties are within the range of Kg/ ^cm2 , the cake is demolded and the stroke length is 5 to 320 mm.
A configuration is employed in which a wire reciprocating at a rate of 10 to 600 times/min is used, and the wire or the cake is cut while being moved at a relative speed of 0.5 m/min or more.

(Function) Since a large cake is molded from the slurry raw material obtained by adjusting the powdered raw material with a specific composition, the hardness etc. of the obtained large cake will be within the specified range. .

Since demolding is performed while the hardness and maximum compressive strength of the large cake are within a specific range, the large cake can proceed to the cutting process while maintaining its shape.In the cutting process, the hardness of the large cake remains within a certain range even after demolding. However, the cake is cut while the hardness is within a predetermined range and the maximum compressive strength is within a specific range, so this cutting is performed on the center side of the large cake. This was done after understanding the characteristics of the
The surface of the ALC molded body becomes smooth and has great strength.

(Example) Next, an example embodying the present invention will be described. A powdery raw material consisting of 40 to 80% by weight of silica sand, 5 to 25% by weight of quicklime, and 5 to 40% by weight of cement becomes 100% by weight in total (taking into account the amount of aluminum powder described later). Adjust as follows,
40-80% by weight, preferably 50-70% by weight of water based on the weight of the powdered raw material was added and the slurry raw material was prepared under stirring for 30 seconds to 5 minutes.

Thereafter, 0.05 to 0.125% by weight of aluminum powder was added to the slurry raw material and mixed for the same time as above to knead the slurry raw material.

The raw material kneaded in this way was fed into a large mold to form a large cake. Then, use a piano wire with a diameter of 0.5 to 1.5 mm as the wire, and apply a stroke length of 5 to 320 mm to the wire, and a stroke length of 10 to 600 mm.
A reciprocating motion was applied at a number of strokes per minute. The reciprocating wire is moved at a speed of 0.5 to 24 m/min in a direction perpendicular to the direction of the reciprocating movement, and is traversed across the large cake;
The large cake was formed into a panel-shaped ALC precursor molded body. This ALC precursor molded body was steam-cured in an autoclave to obtain an ALC molded body. The surface and surface strength of the cut surface of the thus obtained ALC molded body were measured. In addition, in this series of experiments, the hardness of the cake sampled when cutting the large cake was measured using a vane tester (C) manufactured by Marui Co., Ltd.
The maximum compressive strength was also measured. Then, the surface smoothness of the ALC molded body was visually and tactually inspected, and the strength was measured by the method disclosed in the above-mentioned known technique. As a result, the hardness was in the range of 150 to 400 g/ ^cm2 (120 to 280 g/cm2) as shown in Figure 1.
minute)
The range of Kg/cm ² (3 to 4 hours) was good.

The present invention is not limited to the embodiments described above, and may be implemented, for example, in the following embodiments.

(1) 4 of the amount equivalent to the slaked lime produced when quicklime adjusted to a particle size of 1 to 5 mm is hydrated while stirring 2 of pure water at 40°C as quicklime.
The titre after 10 minutes of hydration after dropping the specified amount of hydrochloric acid is
The degree of firing is such that the volume is 300ml or less.
And use one with a CaO purity of 85% or more.

(2) Various cements specified in JIS R5210 to 5213 are used as cement.

(3) Silica stone and silica sand with a silica content of 85% or more can be used as silica raw materials, and fly ash and blast converter slabs can also be used as auxiliary raw materials.

(4) Unit surface area as aluminum powder is 5000~
The powder used is one that has been pulverized to a particle size of 15,000 cm ² /g and that is easily dispersed in water. If the powder is coated with oil or fat, a surfactant may be used in combination.

(5) The powdered raw materials should preferably have the following blending ratio. Silica sand: 50-60% by weight, quicklime: 7-20% by weight, cement: 10-35% by weight, gypsum: 2-8% by weight, aluminum powder: 0.08-0.10% by weight.

Effects of the Invention As detailed above, the present invention exhibits the excellent effect of being able to produce an ALC precursor molded body with a smooth cut surface and a high strength ALC molded body.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between hardness of a large cake and time, and FIG. 2 is a diagram showing the relationship between compressive strength and strain.

Claims (1)

[Claims] 1 (a) Consisting of 40 to 80% by weight of silica sand, 5 to 25% by weight of quicklime, 5 to 40% by weight of cement, 0.5 to 10% by weight of gypsum, and 0.05 to 0.125% by weight of aluminum powder; A step of mixing 40 to 80% by weight of water based on the total weight of powdered raw materials for producing lightweight cellular concrete, the total weight of which is 100% by weight, to obtain a slurry-like raw material, (b) a slurry obtained in the step; (c) A step of molding a shaped raw material to obtain a semi-hardened large cake;
~400g/ ^cm2 and the maximum compressive strength is 0.15~2.0
The cake is removed from the mold when its physical properties are in the range of Kg/ ^cm2 , and the cake is removed using a wire that is reciprocating at a stroke length of 5 to 320 mm, a stroke number of 10 to 600 times/min, and a relative speed of 0.5 m/min. A method for producing an ALC precursor molded body, comprising the step of cutting the wire or the cake while moving it for at least 1 minute.