JP2000016879A - Production of alc(air-bubbled lightweight concrete) - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recycle defective ALC that is disposed as a waist by preventing the ALC panels from forming large cavities and removing dents and/or cavities on the panel faces and recycling the defective ALC that is disposed, as the product qualities such as compression strength are maintained, and provide the production process for ALC panels having excellent productivity and economy. SOLUTION: In the production of ALC panels that uses siliceous raw material, calcareous raw material and the process-repeated raw material are used as main materials, while an aluminum powder is used as a foaming agent, the ALC crushed powder in the process-repeated raw material is formulated instead of a part of the siliceous material in an amount of 15-25 wt.% in the inner percentage based on the whole solid materials or in an amount of 15-25 wt.% in the outer percentage based on the other whole raw materials and the water ratio of the slurry is set to 0.65±0.02. The aluminum powder is prepared by the dry process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a lightweight cellular concrete (ALC) panel, and more particularly to a method for manufacturing an ALC panel capable of preventing generation of cavities and reusing defective ALC. It is about.

[0002]

2. Description of the Related Art Conventionally, ALC has generally been used for building walls,
Used for floors. Such an ALC panel is generally manufactured using a siliceous raw material such as silica stone, a calcareous raw material such as Portland cement and gypsum, and a powder of a raw material for repeating the process as a main raw material, and using an appropriate amount of aluminum powder as a foaming agent. You.

That is, additives such as a surfactant and warm water are added to these main raw materials and kneaded.
Is poured into a mold and cured. The slurry injected into the mold gradually hardens while the hydration reaction between the raw materials and the foaming proceed simultaneously, and a semi-plastic body containing fine bubbles is formed.

[0004] After a desired time has passed and the material has hardened to an appropriate hardness, the semi-plastic body is taken out of the mold, the outer shape is cut into a rectangular parallelepiped having a desired size, and the piano wires are arranged in parallel at intervals according to the panel thickness. Cut using. The obtained panel-like semi-plastic body is charged into an autoclave and steam-cured at a high temperature and a high pressure for a desired time to produce an ALC panel.

In practice, this ALC panel material is cut or cut into various dimensions based on the design specifications of a building,
It cuts grooves on the edge of the long side and chamfers the edges. Further, as required, various designs of the surface are cut and processed, and surface finishing such as application of tiles or painting is performed, and then delivered to a building site.

[0006] In the ALC panel manufactured in this manner, bubbles having a diameter of 2 to 3 mm are uniformly distributed.
When measured according to the method specified in IS A 5417, the dry specific gravity is 0.45 to 0.55 and the compressive strength is 4
~5N / mm ^2, length variation rate is desired to be 0.04% or less.

[0007] In the above-described ALC panel manufacturing process, cutting debris generated when cutting or cutting the upper surface or side surface of the semi-plastic body taken out of the mold, cutting debris of ALC after steam curing in an autoclave, and the like. , ALC defective products occur. These are added to and mixed with the main raw material as raw materials for the process, but it is impossible to reuse all of them. Especially, most of ALC cuttings and defective products after steam curing are disposed of as industrial waste. This is the current situation.

[0008]

In the above-mentioned method of manufacturing an ALC panel, bubbles and cavities are liable to be generated in the process until the slurry foams and hardens in the mold, and particularly large bubbles are formed around the reinforcing reinforcing bar. Cavities were easy to form. In particular, if there is a large cavity having a length exceeding 10 mm, the compressive strength of the ALC panel is reduced, and a hollow due to the cavity is exposed on the panel surface and the edge of the panel, so that the appearance is impaired and the commercial value is reduced. And the need for repairs.

[0009] Further, as for the raw material of the repetition process, the raw material in a semi-plastic state (hereinafter referred to as V1 raw material) has a small amount of generation and is almost constant, and has a water content of only about 120% after hydration reaction. Therefore, almost the entire amount is added to the slurry and reused. On the other hand, in the ALC state after steam curing (hereinafter referred to as V2 raw material), the amount of generation is indefinite, and it is an ALC solid powder having a water content of about 25% after chemical reaction. Of 1
About 0% by weight was the upper limit of the compounding.

For example, the viscosity of the slurry increases as the amount of the V2 raw material increases, so that the ratio of the weight of water to the weight of the total solid raw materials (water ratio) may be increased in order to obtain an appropriate slurry viscosity. As a result, the time until the foaming of the slurry is completed and the curing time are disadvantageously increased. In addition, when the V2 raw material is replaced with a part of a siliceous raw material such as silica stone, there is a problem that the compressive strength of the ALC panel is reduced. For this reason, the remaining defective ALC that cannot be reused as a V2 raw material is treated as industrial waste, and has been a problem economically and from the viewpoint of resource utilization.

The present invention has been made in view of such a conventional situation,
Prevents the generation of large cavities and eliminates depressions on the panel surface,
An object of the present invention is to provide a method of manufacturing an ALC panel which is excellent in productivity and economy by increasing the commercial value and reusing the discarded defective ALC while maintaining the product quality such as the compressive strength. .

[0012]

In order to achieve the above object, the present invention provides a method for manufacturing an ALC panel, which comprises a siliceous raw material such as silica stone, a calcareous raw material such as Portland cement and gypsum, and a raw material obtained by repeating the process. In the method of manufacturing an ALC panel using aluminum powder as a foaming agent and a main raw material, the ALC pulverized powder of the above-mentioned step-repeating raw material is replaced with a part of the siliceous raw material and is divided into 1 by dividing the total solid raw material by
5 to 25% by weight, and the water ratio of the slurry is 0.65 ± 0.6.
02.

A second method of manufacturing an ALC panel according to the present invention comprises a method in which a siliceous raw material such as silica stone, a calcareous raw material such as Portland cement or gypsum, and a raw material obtained by repeating steps are used as main raw materials, and aluminum powder is used as a foaming agent. ALC using
In the panel manufacturing method, the ALC pulverized powder in the raw material for the above-mentioned process is divided into 15 parts with respect to other all solid raw materials.
２５25% by weight, and the water ratio of the slurry was 0.65 ± 0.05.
2.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The causes of cavities during the process of foaming and hardening of a slurry are various, such as the quality and blending ratio of each raw material, the viscosity and temperature of the slurry, the arrangement of reinforcing reinforcing bars, and the air at the time of slurry injection. It is thought that the viscosity of the slurry at the end of foaming, the foaming end time, and the expansion and contraction after foaming are related.

The inventor of the present invention has conducted various studies on the formation of large cavities generated due to these various factors, particularly cavities generated around horizontal reinforcing bars set in a mold. It has been found that shortening the foaming end time in the frame and preventing the subsequent thermal expansion of the slurry are effective in preventing the generation of voids.

As a method of shortening the foaming end time of the slurry and preventing thermal expansion, it is generally considered to lower the water ratio of the slurry. However, in this method, there are problems that the viscosity of the slurry becomes too high, and the curing speed of the slurry becomes too fast, so that the hardness of the semi-plastic body after a predetermined time becomes too high to make cutting impossible.

In the present invention, defective ALC, which is often discarded, is pulverized and mixed as a V2 raw material in a larger amount than before, and at the same time, the water ratio of the slurry is not changed too high or low, and the same as before. By setting the value to about 0.65 ± 0.02, it is possible to shorten the foaming end time of the slurry and to prevent thermal expansion, while maintaining the viscosity of the slurry at such a level that it can be poured. As a result, it is possible to manufacture an ALC panel which does not generate a large cavity and has excellent compressive strength.

That is, in the first method of the present invention, the ALC pulverized powder of the V2 raw material is added instead of a part of the siliceous raw material (the amount of the siliceous raw material is reduced, and the V2 raw material is added by that amount), and all solids are added. The water ratio of the slurry is adjusted to 0.65 ± 0.02 while mixing 15 to 25% by weight of the raw materials. According to this method, the foaming end time and the curing time can be shortened, and the thermal expansion after the foaming end can be reduced.

In the second method, the ALC of the V2 raw material is used.
The pulverized powder is blended in an amount of 15 to 25% by weight with respect to all other solid raw materials, and the water ratio of the slurry is 0.65 ± 0.05.
Let it be 2. According to this method, as in the first method, the foaming end time and the curing time can be shortened, the thermal expansion after the foaming end can be reduced, and the composition of the main material other than the V2 material does not change. Is maintained, and the rate of change in length becomes extremely small.

In any of the methods, the water ratio of the slurry was set to a range of 0.65 ± 0.02 because the water ratio was 0.63.
In the following, the viscosity of the slurry becomes high and the curing time becomes too fast. Conversely, if it exceeds 0.67, the foaming end time and the curing time become long, and the generation rate of voids becomes high.

The aluminum powder used as a foaming agent in the method of the present invention is produced by conventionally used wet pulverization, and may have a specific surface area of about 3.0 g / mm ² , but may be produced by dry pulverization. Aluminum powder is preferred. Aluminum powder obtained by dry pulverization has a specific surface area of about 5.5 g / mm ² and its surface is more oxidized than conventional products, so that foaming start time is delayed, but foaming end time can be further shortened. Therefore, it is more effective to prevent the generation of cavities.

[0022]

EXAMPLE As shown in Table 1 below, silica, quicklime, Portland cement, gypsum, and V1 and V2 raw materials, which are process repeating raw materials, were mixed. Powder and hot water were added so as to have a water ratio shown in Table 1 to form a slurry. However, the blending of the V2 raw material shown in Table 1 is an inner percentage of all solid raw materials in Samples 1 to 7, and an outer percentage with respect to other all solid raw materials in Samples 8 to 13. In addition, the aluminum powder used was wet pulverized in the conventional sample 1, and the dry pulverized aluminum powder was used in all other samples.

[0023]

[Table 1] Silica quick lime Cement gypsum V1 V2 Water ratio sample (wt%) (wt%) (wt%) (wt%) (wt%) (wt%) (%) 1 * 40 5 30 5 10 10 0.65 2 35 5 30 5 10 15 0.65 3 30 5 30 5 10 20 0.65 4 25 5 30 5 10 25 0.65 5 * 20 5 30 5 10 30 0.65 6 * 35 5 30 5 10 15 0.60 7 * 35 5 30 5 10 15 0.70 8 40 5 30 5 10 15 0.65 9 40 5 30 5 10 20 0.65 10 40 5 30 5 10 25 0.65 11 * 40 5 30 5 10 30 0.65 12 * 40 5 30 5 10 15 0.60 13 * 40 5 30 5 10 15 0.70 (Note) Of the samples marked with * in the table, Sample 1 is a conventional example and the others are comparative examples.

The slurry of each of the above samples was poured into a mold having a reinforcing bar disposed in a fixed state, and the foaming completion time and the curing time were measured. The slurry injection temperature was 45 ° C. for all samples. Further, for each of the obtained ALC panels, the rate of occurrence of cavities, the specific gravity of the bulk during drying, the compressive strength, and the rate of change in length were measured, and the results are shown in Table 2 below.

The foaming end time is the time from when the slurry is injected until the height of the slurry in the mold reaches the maximum. In addition, the curing time was determined by dropping an iron ball having a diameter of 45 mm onto the surface of the semi-plastic body from a position having a height of 50 mm, and injecting the slurry until the diameter of the depression formed on the surface of the semi-plastic body became 25 mm. From 210 to 210
70 minutes is a suitable time. The dry bulk specific gravity, compressive strength, and length change rate of the ALC panel were measured by the methods specified in JIS A 5417. The void generation rate is a ratio of the panel in which a dent having a length of 10 mm or more is found on the panel surface.

[0026]

[Table 2] Foaming time Curing time Cavity generation Compressive strength Length change rate Sample (min) (min) (%) Bulk specific gravity (N / mm ² ) (%) 1 * 70 250 3.0 0.48 4.71 0.032 2 60 250 0.1 0.48 4.60 0.030 3 50 250 0 0.48 4.52 0.029 4 40 245 0 0.48 4.33 0.027 5 * 30 245 0 0.49 3.91 0.026 6 * 30 200 0 0.49 4.57 0.030 7 * 70 280 2.9 0.48 4.59 0.031 8 65 250 0.2 0.50 4.75 0.029 9 55 250 0.1 0.51 4.73 0.028 10 45 250 0 0.53 4.71 0.022 11 * 40 245 0 0.56 4.60 0.027 12 * 30 200 0 0.52 4.70 0.028 13 * 70 280 3.1 0.50 4.66 0.029 (Note) Of the samples marked with * in the table, Sample 1 is a conventional example and the others are comparative examples.

In the conventional example of Sample 1, there is no problem in the basic performance such as the dry bulk specific gravity, the compressive strength, and the length change rate of the ALC panel. However, since the foaming end time is long, the subsequent thermal expansion becomes large and the cavity becomes hollow. Is increasing.

On the other hand, in Samples 2 to 4 according to the first method of the present invention, although the compressive strength of the ALC panel is slightly reduced, the foaming end time is shorter than before, and the generation of voids is extremely reduced. I understand. In particular, Sample 3 containing 20% by weight of the V2 raw material has the best results among Samples 2 to 4, including the quality such as the compressive strength.

On the other hand, Sample 5 which is a comparative example of the first method
However, since the V2 raw material is used in a large amount, the compressive strength of the ALC panel is significantly reduced. In addition, the blending of V2 raw material is 15% by weight
In Sample 6, in which the water ratio was reduced to 0.6, no voids were generated, but there was a problem in workability because the foaming end time and the curing time were too early. On the contrary, sample 7 in which the water ratio was increased to 0.7
In this case, since the foaming end time is long, the void generation rate is high, and the curing time is too slow, which causes a problem in productivity.

Next, samples 8 to 8 according to the second method of the present invention were prepared.
10 is an example in which the V2 raw material is compounded on an external basis. In each case, the specific gravity of the ALC panel is 0.50 to 0.53, which is slightly higher than the conventional one, but the compressive strength is maintained and the length change rate is small. In addition, the void generation rate is extremely low. In particular, Sample 10 containing 25% by weight of the V2 raw material showed the best results in all respects.

On the other hand, sample 11 which is a comparative example of the second method was used.
Means that ALC is used because V2 raw material is as large as 30% by weight.
The bulk specific gravity of the panel is too high at 0.56. Also, V
In Sample 12, in which the mixing ratio of the two raw materials was 15% by weight and the water ratio was reduced to 0.6, no cavities were generated, but there was a problem in workability because the foaming end time and the curing time were too fast. Conversely, in Sample 13 in which the water ratio was increased to 0.7, the foaming end time was long, the void generation rate was high, and the curing time was too slow, which had a problem in productivity.

[0032]

According to the present invention, since the time required for foaming the slurry to be completed can be shortened and the thermal expansion after the foaming has been completed can be reduced, the occurrence of large cavities can be prevented, the dents on the panel surface can be eliminated, and commercial products can be manufactured. It is possible to provide an ALC panel which has high value and at the same time maintains quality such as compressive strength. In particular, according to the second method in which the ALC pulverized powder is blended on an external basis, it is possible to manufacture an ALC panel having excellent compressive strength of the ALC panel and an extremely small length change rate.

Further, according to the present invention, the compounding of the ALC pulverized powder among the raw materials of the process repetition can be greatly increased as compared with the conventional one, so that the resources such as defective ALC which has been mostly discarded in the past can be effectively used. It can be used, and raw material costs and industrial waste disposal costs can be reduced. Therefore, it is extremely useful in practical use, since it is possible to almost completely prevent the occurrence of cavities while maintaining the workability and the basic performance of the product while being excellent in economic efficiency.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C04B 22:04) 111: 40

Claims (3)

[Claims] 1. A method for manufacturing an ALC panel using a siliceous raw material such as silica stone, a calcareous raw material such as Portland cement or gypsum, and a raw material for repeating the process, and using aluminum powder as a foaming agent. ALC powder is blended with 15 to 25% by weight of the total solid raw material instead of a part of the siliceous raw material, and the water ratio of the slurry is 0.65 ± 0.02. ALC
Panel manufacturing method. 2. A method for manufacturing an ALC panel using a siliceous raw material such as silica stone, a calcareous raw material such as Portland cement or gypsum, and a raw material for repeating the process, and using aluminum powder as a foaming agent. ALC powder was blended in an amount of 15 to 25% by weight with respect to all other solid raw materials, and the water ratio of the slurry was 0.65.
A method for manufacturing an ALC panel, wherein ± 0.02 is set. 3. The method for producing an ALC panel according to claim 1, wherein an aluminum powder obtained by dry pulverization is used as a foaming agent.