JPH0665637B2 - Method for producing lightweight foam concrete body - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a lightweight cellular concrete body that is cured under high temperature and high pressure steam pressure.

(Prior Art) A conventional lightweight cellular concrete body is manufactured as follows.

First, a slurry obtained by mixing finely pulverized silica stone, silica sand, a siliceous raw material such as fly ash and a powdered calcareous raw material such as cement, quick lime, and slaked lime with a foaming agent such as water and metallic aluminum. Is poured into the formwork, for example, into a formwork in which a rustproof basket-shaped reinforcing bar is set at a predetermined position. Then, the volume of the poured slurry expands about twice due to the foaming of the foaming agent such as metallic aluminum, and at the same time, the hydration of the hardening component proceeds to form a mortar containing bubbles.

As a method of forming mortar containing bubbles, in addition to this, a method of mixing bubbles formed in advance by using a foaming agent during slurry production, or using a siliceous raw material and a calcareous raw material as raw materials There is a method in which a foaming agent is mixed and stirred in a slurry prepared by adding the above ingredients to foam the slurry.

After the mortar containing these bubbles reaches a predetermined hardness, it is carried on a cutting machine using a block-carrying crane or the like and cut into a predetermined size to form a panel. The cutting method is to push out the mortar with a piano wire having a diameter of about 1 mm.

This cut panel is about 160 ~ in the autoclave.
Cure at 180 ° C under high temperature and high pressure steam pressure for 4 to 10 hours.

The cured panel usually has a small edge end face cut to improve the dimensional accuracy and to obtain an end face suitable for a construction application. In addition, the surface may be cut to form an uneven pattern for the purpose of improving the design of the panel surface.

The lightweight cellular concrete body thus obtained is widely prized as an outer wall material, a roof material and the like because of its light weight, high heat insulation and excellent workability.

(Problems to be Solved by the Invention) The above-mentioned conventional method for manufacturing a lightweight cellular concrete body is
A process of using a formwork in which basket-like reinforcing bars are set in advance, making mortar hardened to a predetermined hardness as a block-shaped large mass, and cutting it with a piano wire to divide it into the desired panel size. Therefore, a large formwork (usually width 1.5 m x height 0.7 m x length 6 to 7.2 m) and a lot of jigs for holding cage-shaped reinforcing bars in the formwork are required. Not only is there a need for expensive equipment such as a block-carrying crane and a cutting machine for cutting and dividing the block into predetermined panel sizes, but the building for installing these large facilities is also vast. However, a large amount of capital investment is required to set up the factory, and this has forced us to take the form of mass production for profitability.

Also, in order to cut and divide the block into the size of a predetermined panel as described above, it is necessary to cut using a piano wire, so the shape of the edge end face is limited, and the panel cut with the piano wire is It can only be a flat plate with a flat end face shape and a flat surface, and in order to construct the panel as a wall material, the end face of the panel is cut after being cured under high temperature and high pressure steam pressure (hereinafter referred to as autoclave curing). However, a separate step of cutting the surface of the autoclave-cured panel is required in order to form an uneven pattern on the panel surface and improve the design, which is also complicated.

For the purpose of improving the bending strength of the base material of the lightweight cellular concrete and improving the easiness of chipping, when using mortar mixed with fibers, cut the block into the prescribed panel size as described above. In order to do so, it is necessary to cut with a piano wire, but a fiber having a length effective for modification is entangled with the piano wire at the time of cutting, which causes a problem that the block cannot be cut.

The object of the present invention is to solve the above-mentioned problems, without the need for a huge facility that requires a vast area for factory installation, in a small amount of production, a method for producing a lightweight cellular concrete body having the end face shape of the final product. Is to provide.

(Means for Solving the Problems) The method for producing a lightweight cellular concrete body of the present invention comprises a powdery siliceous raw material and a powdery calcareous raw material as main raw materials, and bubbles are contained in advance by a foaming agent or a foaming agent. The tobermorite is characterized in that after that, the mortar, which is in a non-foaming state, is shaped by an extruder and discharged without the presence of other cementitious materials around it, and then cured under high temperature and high pressure steam pressure. It is a method for producing a lightweight cellular concrete body having crystals.

In the production method of the present invention, fibers can be added to the mortar if necessary.

As the powdery siliceous raw material and the powdery calcareous raw material used in the present invention, those used in the conventional production of lightweight cellular concrete can be used. Moreover, as a mixing ratio of these, a molar ratio of CaO and SiO ₂ is usually 0.3.
More preferably, it is from 1.0 to 1.0. When it is less than 0.3, tobermorite is not sufficiently produced even by autoclave curing, the base material strength is insufficient, and the resistance to neutralization is remarkably low, which is not preferable. When it is more than 1.0, the resistance to neutralization is low, which is not preferable.

In general, in order to discharge foamed mortar while shaping it with an extruder, it is necessary to maintain fluidity having a shape-retaining property such that the mortar can maintain its own shape after coming out of the extruder die. In the invention, as a method of preliminarily containing air bubbles in the mortar, a method of mixing a foaming agent such as metal aluminum powder in advance with the raw material mortar to foam, or mixing air bubbles previously formed using a foaming agent during mortar production And a method in which a foaming agent is mixed and stirred in a mortar made by adding water or the like to a raw material mainly composed of a siliceous raw material and a calcareous raw material to foam.

However, when a mortar that does not contain bubbles in advance and that foams after being discharged from the extruder is used, or when mortar that continues foaming during discharging is discharged from the extruder while being shaped, a product obtained Not only is the dimensional accuracy significantly deteriorated, but cracks are also generated on the surface, which is not preferable, and as in the present invention, a mortar that contains bubbles in advance with a foaming agent or a foaming agent and is not foamed thereafter is used. It is necessary to discharge while shaping with an extruder.

For this reason, when using a normal light-weight cellular concrete raw material slurry that uses metallic aluminum as a foaming agent, foaming is completed, and it is further cured for about 1 hour or more, and then self-molded after it is discharged from the die of the extruder. It is desirable to use a mortar that retains fluidity and retains its shape.

It should be noted that at the time of discharging, it is necessary to perform the shaping by an extruder without discharging other cementitious material around it. For example, if the lightweight cellular concrete body is covered with a solid cement mortar and discharged to make it covered with a solid cement body, the specific gravity of the product itself increases because there is a solid cement body, Not only does it become inferior in terms of lightness, but the part of the lightweight aerated concrete body filled inside is not sufficiently cured even by autoclave curing, and tobermorite crystals are found in the part of the lightweight aerated concrete body. However, the lightweight cellular concrete body itself is remarkably inferior in strength and resistance to neutralization.

The content of bubbles in the present invention is 5 to 60.
Volume% is preferred. If the amount is less than 5% by volume, the weight reduction is insufficient, which is not preferable. On the other hand, if it is more than 60% by volume, the volume change after ejection is large and the dimensional accuracy is lowered, which is not preferable.

Further, in the present invention, by the presence of bubbles due to the foaming agent or foaming agent, it is possible to discharge a lightweight product in a good state,
No significant defects occur on the product surface. Further, in the mortar which is preliminarily containing bubbles by a foaming agent or a foaming agent and is not foamed thereafter, perlite, vermiculite, silas paloon, expanded styrene beads, etc., within a range not impairing the expression of the above effects. The lightweight aggregate may be used together to further reduce the weight.

In the present invention, addition of a thickening substance is preferable as a method for further improving the shape retention property. As the thickening substance, an organic additive such as polyvinyl alcohol or polyethylene oxide can be used in addition to a cellulose derivative such as methyl cellulose. Also,
As the inorganic thickening substance, asbestos, bentonite, kaolin, gel-like calcium silicate hydrate and the like can be used.

In addition, when it is necessary to further reinforce with a reinforcing bar depending on the purpose of use of the product, a reinforcing bar subjected to anticorrosion treatment can be inserted, for example, by the method described in JP-B-53-13208. .

Further, when the base material of the lightweight cellular concrete is improved by mixing reinforcing fibers, the reinforcing fibers for modification include glass fibers, carbon fibers, steel fibers, pulp, nylon fibers, propylene fibers, polyethylene fibers, and asbestos. Fibers such as, sepiolite and wollastonite can be used. In order to enhance the modifying effect, it is preferable to use one having a fiber length of several mm or more.

Then, in order to carry out uniform curing in autoclave curing, it is necessary that the lightweight cellular concrete body is not covered with a solid cement body, and like the case of manufacturing a conventional lightweight cellular concrete body, After the mortar is sufficiently hardened, it is preferable to put it in an autoclave, subject the autoclave to a reduced pressure treatment, and then introduce steam to cure it. The curing time is preferably 4 to 10 hours under a high temperature and high pressure steam pressure of 180 ° C. or higher. By curing under this high temperature and high pressure steam pressure, tobermorite crystals are generated, and product performance such as strength and resistance to neutralization is improved.

(Example 1) 7 parts by weight of powdered lime (the following parts are all parts by weight), 34 parts of ordinary Portland cement, 40 parts of powdered silica stone, 2 parts of powdered gypsum, 15 parts of 6-class asbestos , 2 parts of pulp, 1 part of methyl cellulose, 0.04 part of metal aluminum powder, and 55 parts of kneading water were mixed at 40 ° C., and then kneaded in vacuum. Subsequently, the mortar was foamed with the aluminum metal in the mortar, and after the foaming was completed, the mortar was left standing for 1.5 hours for curing. Then, the mixture was discharged while being shaped by using a flat plate die (thickness 15 mm × width 150 mm) by an extruder. After curing the obtained flat plate at 60 ° C. for 24 hours, 1
A product was obtained by aging for 8 hours under a high temperature and high pressure steam pressure of 80 ° C. The specific gravity of the product was 0.8.

Table 1 shows the appearance and dimensional accuracy of the obtained product, the bending strength, and the confirmation results of the formation of 11Å crystalline tobermorite by the powder X-ray diffraction method.

(Example 2) As a powdery siliceous raw material, 50 parts of Shirasu from Hokkaido Takeura (powdered silica having a particle size of 1.7 mm or less), 35 parts of ordinary Portland cement, 12 parts of 6-class asbestos, and pulp 2
Parts, methyl cellulose 2 parts, metallic aluminum powder 0.
01 parts and 65 parts of kneading water were mixed at 40 ° C., and then kneaded in vacuum. The subsequent treatment was the same as in Example 1, and various properties of the obtained product are shown in Table 1. The specific gravity of the product was 0.97.

(Comparative Example 1) Metal aluminum powder having the composition used in Example 2 was mixed, and mortar immediately after vacuum kneading was ejected while being shaped by an extruder using a flat plate die (thickness 15 mm x width 150 mm). did. After discharging from the extruder, there was foaming due to metallic aluminum. The obtained flat plate was aged at 60 ° C. for 24 hours in the same manner as in Example 1, and then aged at 180 ° C. under a high temperature and high pressure vapor pressure for 8 hours to obtain a product. Table 1 shows various properties of the obtained product.

(Comparative Example 2) Metal aluminum powder having the composition used in Example 1 was mixed and vacuum kneaded, and then mortar after about 30 minutes passed was extruded into a flat plate die (thickness 15 mm x width 150 m).
m) was used for shaping and discharging. There was foaming due to metallic aluminum during discharge from the extruder. The obtained flat plate was cured at 60 ° C. for 24 hours in the same manner as in Example 1, and then 180 ° C.
The product was obtained by curing under high temperature and high pressure steam pressure for 8 hours. Table 1 shows various properties of the obtained product.

(Comparative Example 3) Of Example 2, a product was prepared without curing under high temperature and high pressure steam pressure. Table 1 shows various properties of the obtained product.

As is clear from Table 1 above, Comparative Example 1 and Comparative Example 2
In addition, not only surface cracks occurred but also swelling occurred on the surface due to foaming after discharge and foaming during discharge. Further, therefore, even a sample for measuring bending strength could not be obtained.

The product of Comparative Example 3 not subjected to autoclave curing had no tobermorite crystals and had a bending strength of 7
Not only it was as low as kg / cm ² , but also the resistance to neutralization was low, and cracks due to shrinkage occurred one month after production.

On the other hand, in Examples 1 and 2 which are the manufacturing methods of the present invention, the dischargeability was uniform, and the appearance properties including the surface smoothness and the dimensional accuracy were good. In addition, 11 Å crystalline tobermorite is generated, and the bending strength is 63 kg each.
/ Cm ² , 82 kg / cm ^{2, which} is high, and although not shown, the resistance to neutralization is also high.

Further, in the above embodiment, a flat plate-shaped die was used, but by using a die having a shape suitable for the tongue structure of the end face required by the product or a die having an uneven pattern on the surface, The end face condition and surface condition of the product can be obtained, and like a conventional lightweight cellular concrete body produced by cutting with a piano wire, after the autoclave curing, the end face or surface is cut in a separate process to obtain the desired end face condition or surface condition. The step of setting is not particularly required.

(Effects of the Invention) The present invention is mainly composed of a powdery siliceous raw material and a powdery calcareous raw material, containing bubbles in advance by a foaming agent or a foaming agent, and a mortar in a state that does not foam thereafter, Since it is a method for producing a lightweight cellular concrete body having a tobermorite crystal, which is characterized in that it is discharged without being coated with another material while being shaped by an extruder, and then cured under high temperature and high pressure steam pressure, the present invention According to this, it does not require a huge facility that requires a vast area to set up a factory that manufactures lightweight cellular concrete with a specific gravity of 1 or less, can be produced in small quantities, and has uniform dischargeability and surface smoothness. It has good appearance and dimensional accuracy including 11 Å
Excellent in various aspects from which crystalline tobermorite is generated, a product with high bending strength and high resistance to neutralization can be obtained, and a lightweight cellular concrete body having the end face shape of the final product can be obtained by extrusion molding. Performance is demonstrated.

Claims (1)

[Claims] 1. A mortar containing a powdery siliceous raw material and a powdery calcareous raw material as main raw materials, containing bubbles in advance by a foaming agent or a foaming agent, and then not being foamed by an extruder. A method for producing a lightweight cellular concrete body having tobermorite crystals, which comprises ejecting without forming other cementitious material around it while forming, and then curing under high temperature and high pressure steam pressure.