JPH06157159A - Molding method for lightweight cellular concrete - Google Patents

Abstract

PURPOSE:To obtain a molded body with suppressed pit defects on the surface by casting a lightweight cellular concrete mortar containing a specified amt. of water reducing agent in a molding flask, vibrating the mortar with a vibrator, and then molding by foaming. CONSTITUTION:A slurry essentially consisting of a silica source material (e.g. is silica powder) and a lime source material (e.g. normal portland cement) is mixed with a water reducing agent by >=0.05wt.%. solid proportion (e.g. high condensation salt of naphthalene sulfuric acid and formalin) and further with a foaming agent (e.g. metal aluminum powder) and water to prepare a slurry. Then the obtd. mortar for lightweight cellular concrete is cast into a molding flask. The cost mortar is vibrated with a vibrator. Then by a general method the cost mortar is molded by foaming, released from the molding flask, cut with a piano wire, aged in an autoclave, etc., to obtain a lightweight cellular concrete product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding lightweight cellular concrete (hereinafter referred to as ALC), and more particularly to a method for molding ALC which suppresses the generation of avatar-shaped defects on the surface of ALC.

[0002]

2. Description of the Related Art ALC, which is widely used as a building material, such as ALC wall panel, usually contains silica stone raw material and calcareous raw material as main components, and a foaming agent such as metallic aluminum and water are added thereto to form slurry mortar. The obtained mortar block is demolded in a semi-cured state by pouring it into a mold, cutting the upper and side ends of the mortar block with a piano wire, etc. and dividing it to a predetermined size, then autoclaving It is made by curing. This AL
Reinforcing bars are usually embedded in C during its molding.

[0003]

Problems to be Solved by the Invention Conventionally, the surface of ALC manufactured as described above often causes avatar-like defects, which has been a problem in quality control. It was found that this was mainly due to the air entrained when the mortar was poured into the mold. That is, the entrained air is dispersed as air bubbles in the mortar in the mold and rises and escapes to the atmosphere, part of which is due to factors such as the viscosity of the mortar or its local imbalance. , It does not escape from the mortar and remains partly in the mortar. Such residual bubbles remain as voids in the hardened mortar block, but when they appear on the surface cut with a piano wire or the like, the above-mentioned avatar-like defects occur.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the problems in the conventional ALC molding method and to provide a molding method capable of suppressing the occurrence of such avatar-like defects. .

[0005]

The molding method of the present invention for solving the above-mentioned problems is a molding method of lightweight cellular concrete in which mortar for lightweight cellular concrete is poured into a mold and foam-molded. It is characterized in that a mortar for lightweight cellular concrete containing 1% by weight or more of a water reducing agent is injected into a mold, and the injected mortar is vibrated by a vibrator.

The mortar for ALC used in the present invention comprises silica raw material and calcareous raw material as main components, and a foaming agent and water are added thereto to form a slurry. Silica powder, silica stone, flasheye, etc. can be used as the silica raw material, and cement, quick lime, etc. can be used as the calcareous raw material. Further, if necessary, ALC crushed waste may be partially mixed.

Cement is used as a typical mortar composition.
0 to 50% by weight, quicklime 1 to 15% by weight, the rest silica powder, and a small amount of metallic aluminum powder as a foaming agent and water. In addition, the compounding C / S (C
The aO / SiO ₂ molar ratio) is usually about 0.4 to 0.7. The slurry viscosity is usually (450-600 gc
m), and if this value is too high, the fluidity becomes low and the slurry cannot be injected smoothly into the mold, while if this value is too low, the molding time becomes too long and the efficiency falls.

In the present invention, a water reducing agent is further contained in the mortar, and as the water reducing agent, a commercially available water reducing agent for concrete mortar can be used. For example, naphthalene sulfonic acid and formalin containing a high water reducing agent can be used. There are sulfonic acid-based polymer compounds such as condensate salts, lignin sulfonate, and alkylallyl sulfonate polymer. The content of the water reducing agent in the mortar is 0.05% by weight or more in terms of solid content, preferably 0.1 to
It is 0.3% by weight or more. If the amount is less than 0.05% by weight, the above-mentioned effects aimed at by the present invention are deteriorated. Also 0.3
Even if it is more than wt%, the above effect cannot be expected so much.

When the mortar slurry thus prepared is next poured into a mold, a vibrator is used to vibrate the slurry. That is, in order to effectively exert the effect of suppressing the avatar-like defects generated on the ALC surface, which is the object of the present invention, as shown in Examples described later, the mortar slurry contains a predetermined amount of a water reducing agent. It is not enough just to make it, and in addition, it is necessary to give vibration to the injected mortar slurry by the vibrator.

The vibrator to be used may be, for example, an electric type using a motor and a cam or an electromagnetic vibration type. In any case, a vibrator for inserting it into the mortar slurry and vibrating it with a predetermined vibration energy is used. It is necessary to have it as an output part. The vibration output from the vibrator has an amplitude (0.5 to 0.7 mm) and a frequency (240 to 6 mm).
0 Hz) is preferable. Further, the vibration energy may be appropriately determined in proportion to the range in which the mortar is vibrated, but when using a plurality of vibrators, the required energy per unit can be reduced by that much. The vibration to this mortar slurry should be given for a sufficient time to suppress the avatar-like defects generated on the ALC surface.
According to the experiment, the mortar slurry for C (90 to 180
Seconds), preferably about (120 to 150 seconds), is sufficiently effective.

After injecting the mortar slurry into the mold in this way, foam molding in the mold, demolding, cutting with a piano wire, and curing with an autoclave are carried out in the same manner as in the usual ALC manufacturing method. To make an ALC product.

[0012]

EXAMPLES Next, examples of the present invention and comparative examples will be described. Silica powder 50% by weight, ordinary Portland 40% by weight,
Quick lime 8% by weight, gypsum 2% by weight, aluminum powder 0.6
Water was added to the weight percent, and a highly condensed salt of naphthalene sulfonic acid and formalin (commercially available from Kao as Mighty 150) as a water reducing agent was mixed in a solid content ratio to prepare a mortar slurry. The viscosity of this mortar slurry was 400 to 450 gcm, and the C / S was 0.68.

Next, this mortar slurry was injected into the mold, and a vibration device (manufacturer; Hayashi vibrator, model P23DL) was installed in the mold near the injection part and vibrated at an amplitude of 0.6 m and a frequency of 200 Hz. And was impregnated during and 0.5 minutes after injection of the mortar slurry. Note that, as a comparative example, the same procedure was performed when a mortar slurry containing no water reducing agent was used and when no vibration was applied.

Next, the avatar-like defects existing on the surface of the ALC obtained by subjecting these to foam molding, cutting, and autoclave curing were examined, and the results are also shown in Table 1. Note that autoclave curing is 4 at 180 ° C and 10 Kg / cm ² G.
I went on time.

[0015]

[Table 1] As can be seen from the results in Table 1, the surface of the ALC obtained by using the mortar slurry containing a predetermined amount of the water reducing agent according to the method of the present invention, and performing foam molding by vibrating with a vibrator at the time of pouring the mold. The avatar-like defects of are extremely thin. On the other hand, the avatar-like defects on the surface of the ALC become large when at least one of the use of the water reducing agent and the application of vibration is lacking.

The avatar generation rate in Table 1 was calculated by the following method. That is, 1m x 60c of the molded body
The bubble unevenness in the region of m is measured, and it is converted into the following avatar coefficient. The ratio of the avatar coefficient in the range of 300 or more is the avatar generation rate. Avatar coefficient = (number of bubble irregularities of 3 mm to 5 mm) × 1
6+ (number of bubble unevenness of 5 mm to 7 mm) × 36 + (7
mm-10 mm number of bubble unevenness) × 64 + (number of bubble unevenness of 1 mm or more) × 100

[0017]

The ALC molding method of the present invention can remarkably suppress avatar-like defects on the surface by adopting the above constitution.

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Claims (1)

[Claims] 1. A method for forming a lightweight cellular concrete in which the mortar for lightweight cellular concrete is injected into a mold and foam-molded, wherein a mortar for lightweight cellular concrete containing 0.05% by weight or more of a water reducing agent in terms of solid content is used. A method for molding lightweight cellular concrete, which comprises injecting into a mold and giving vibration to the injected mortar by a vibrator.