JP2020040871A - Lightweight cellular concrete - Google Patents

Abstract

To provide a lightweight cellular concrete reduced in minute defects in processing surface joints (cut grooves) and having highly designable surface peeling processability.SOLUTION: A lightweight cellular concrete having a specific gravity of 0.2 or more and less than 0.45, wherein a ratio of an insoluble residue in the lightweight cellular concrete is 5 mass% or more and less than 20 mass% based on the whole solid content, and assuming that particles having a diameter of less than 10 μm in the insoluble residue are fine particles, that particles having a diameter of 10 μm or more and less than 100 μm are middle particles and that particles having a diameter of 100 μm or more are coarse particles, a content of the coarse particles in the insoluble residue is 2.0 mass% or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to lightweight cellular concrete (hereinafter, also referred to as ALC). More specifically, the present invention provides a lightweight cellular concrete (hereinafter, referred to as a low specific gravity of 0.2 to less than 0.45), which has a small number of small defects in surface joint (cutting groove) processing and is excellent in surface peeling processing characteristics having high designability. , Low specific gravity ALC).

ALC is bulk while a specific gravity of 0.45 to 0.55 and weight, since containing a large amount of highly crystalline tobermorite _{(5CaO · 6SiO 2 · 5H 2} O), has the necessary strength as a building material Excellent in long-term weather resistance, fire resistance, indestructibility, lightweight, and easy to work because of excellent workability, widely used as exterior materials, floor materials, interior materials, roof materials, etc. For example, there are cases in which cutting is performed to various dimensions based on a design specification of a building, a groove is cut in a small side surface of a long side, chamfering of an edge is performed, or the like. Further, in recent years, as shown in FIG. 3, for example, a complex design pattern may be formed on the surface of the ALC by cutting or peeling to increase added value.
ALC is mainly composed of cement and silica stone powder, and if necessary, quicklime powder, gypsum, etc. are added thereto, water is added to form a slurry, and the mixture is foamed with a foaming agent such as aluminum powder at atmospheric pressure. It is manufactured by molding and autoclaving. The compressive strength of ALC is usually in the range of 4-5 N / mm ² , and the flexural strength is in the range of 1-1.5 N / mm ² .

  Normal concrete has a specific gravity of about 2.0, whereas ALC has a specific gravity of 0.45 to 0.55, and its weight is reduced by including many voids inside. In the ALC, about 80% of the volume is voids, but in the low specific gravity ALC of 0.2 or more and less than 0.45, the void volume is usually larger than that of the conventional ALC.

Patent Literature 1 below discloses a method for producing a ALC having excellent physical properties such as strength by adjusting the particle size of silica used as a siliceous raw material. When the silica stone is defined as a fine particle having a particle diameter of less than 10 μm, a medium particle having a particle size of 10 μm or more and less than 100 μm, and a coarse particle having a particle size of 100 μm or more, the mass percentage of the coarse particle is 9 to 15%. A method for producing ALC, wherein the mass ratio of fine particles / medium particles is 0.9 to 1.2 is disclosed.
Patent Document 1 discloses that by adjusting the mass ratio of fine particles to medium particles to 0.9 to 1.2, the formation of crystal nuclei and crystal growth of tobermorite are promoted in a well-balanced manner, and sufficient tobermorite is generated. It has been considered that by setting the mass percentage of the coarse particles to 9 to 15%, the remaining coarse particles serve as an aggregate effect, and synergistically improve the ALC strength.
Although the ALC described in Patent Literature 1 achieves a compressive strength of 4.8 N / mm ² or more, it contains 9% by mass or more of coarse particles of ground silica as a raw material. Is estimated to be about 35% by mass with respect to the total solid content, the coarse silica in the insoluble residue is estimated to be at least 10% by mass, and the absolute dry bulk specific gravity is about 0.5. That is, Patent Literature 1 does not disclose a low specific gravity ALC having a specific gravity of less than 0.2 to 0.45, and has a problem of generation of minute defects in surface joint processing in the low specific gravity ALC and a high surface design. No mention is made of the release processing characteristics.

Patent Literature 2 below discloses an ALC that has a strength required as a building material while being lightweight with a bulk specific gravity of 0.45 to 0.55, and is excellent in long-term weather resistance, fire resistance and endurance resistance. For the purpose of cutting or cutting into various dimensions based on the design specifications of the building, cutting grooves on the small side of the long side, or preventing chipping or cracking that occurs when performing chamfering of the edge, etc. An ALC containing a siliceous raw material mainly composed of silica stone and silica sand, a calcareous raw material, water and a foaming agent, wherein the particle size of an insoluble residue in the lightweight cellular concrete is less than 10 μm. When fine particles having a size of 10 μm or more and less than 100 μm are medium particles and those having a size of 100 μm or more are coarse particles, the content of the coarse particles in the insoluble residue is 0.1 to 40% by mass, The mass ratio of the fine particles is ALC is disclosed a .01～0.7.
According to Patent Document 2, fine particles having a particle size of the crushed silica stone and silica sand of less than 10 μm have a property of promoting generation of tobermorite up to a certain amount. On the other hand, on the other hand, the insoluble residue in the ALC becomes fine particles and has the property of increasing the occurrence of defects and cracks during ALC processing; medium particles having a particle size of 10 μm or more and less than 100 μm Has the property of promoting the generation of tobermorite, and the insoluble residue in ALC has an appropriate particle size, so that the generation of defects and cracks during the processing of ALC can be suppressed; and when the particle size is 100 μm or more, Certain coarse particles do not have the property to promote the formation of tobermorite as fine particles (up to a certain amount) and medium particles, but because the insoluble residue in ALC becomes coarse, It can be greatly suppressed generation of definitive defect or crack; is described. The teaching teaches 0.1 to 0.7 as the mass ratio of fine particles / medium grains in the insoluble residue, and teaches 0.1 to 40% by mass as the content of coarse particles in the insoluble residue. The content of the coarse particles in the insoluble residue in Examples of Patent Document 2 is 4.2 to 19.5% by mass.
Although the ALC described in Patent Document 2 achieves an extremely low occurrence rate of defects and cracks, it contains 4.3 to 17.0% by mass of coarse particles of ground silica as a raw material. Is estimated to be about 30% by mass with respect to the total solid content, and its absolute dry bulk specific gravity is also about 0.5. That is, Patent Literature 2 does not disclose a low specific gravity ALC having a specific gravity of less than 0.2 to 0.45, and has a problem of generation of minute defects in surface joint processing in the low specific gravity ALC and a high surface design. No mention is made of the release processing characteristics.

By the way, in recent years, from the viewpoint of demand for further weight reduction of buildings, improvement of safety at the time of on-site work and reduction of burden on workers, a low specific gravity ALC having a lower specific gravity has been developed while maintaining the features of the conventional ALC. It has been demanded. As the low specific gravity ALC, those containing a larger amount of bubbles due to the foaming agent than before are generally used. As a method of realizing a low specific gravity, when a large amount of air bubbles is contained, the air bubble diameter becomes large and the ratio of the coarse air bubbles due to the foaming agent to the total volume becomes large, resulting in a significant decrease in strength. Therefore, it has been proposed to use a thermoplastic resin or an alkaline earth metal carbonate or to use silica powder having a large specific surface area. However, the reduction in compressive strength accompanying the reduction in bulk specific gravity cannot be avoided. When the specific gravity is 0.35 to 0.40, the compressive strength is about 1.5 to 3.25 N / mm ² , and the strength is generally lower than that of the conventional ALC.

JP 2007-99546 A Japanese Patent No. 6134278

As described above, ALC may be cut into various dimensions based on the design specification of the building, may be cut into a groove on a long side small face, or may be subjected to chamfering of an edge, and the like. In recent years, there is a case where a complex design pattern is applied to the surface of the ALC by cutting or peeling to increase the value added. In this case, cutting, cutting, chamfering, surface cutting / peeling of the ALC are performed. In such a case, chipping or cracking may occur. However, with respect to the low specific gravity ALC having different specific gravity, insoluble residue, and particle size distribution in the insoluble residue from the conventional ALC, for the purpose of suppressing chipping and cracking, the particle size and product There is no study on the particle size of the insoluble residue in ALC.
Under such circumstances, the problem to be solved by the present invention is that, even in low specific gravity ALC, for a long time, even when surface joint processing or groove cutting is performed, there is little micro-defect, and the surface has excellent surface design and excellent peeling properties. It is to provide lightweight cellular concrete.

  The inventors of the present application have conducted intensive studies and repeated experiments to solve the above-mentioned problems. As a result, conventionally, in ordinary ALC that is not low in specific gravity, fine particles having a particle size of silica stone and silica sand of less than 10 μm after grinding are constant. If the amount is larger than the amount, it has a property of inhibiting the generation of tobermorite, and if the ratio of fine particles of the insoluble residue in ALC increases, the generation of defects and cracks during ALC processing increases, and the coarse particles in the insoluble residue also increase. It was taught that when the ratio of ALC was high, it was possible to greatly suppress the occurrence of cracks and cracks during the processing of ALC, but contrary to such teaching, insoluble in low specific gravity ALC having a bulk specific gravity of 0.2 or more and less than 0.45. When the ratio of the residue was 5% by mass or more and less than 20% by mass with respect to the total solid content, and when the content of coarse particles in the insoluble residue was 2.0% by mass or less, cutting was performed for a long time. Sometimes fine Small defects (fine defects), and the ratio of fine particles / medium particles in the insoluble residue is 0.75 or more and 1.40 or less (less than the range of 0.1 to 0.7 taught in Patent Document 2). Unexpectedly, it was found that when the height is high, the properties of the surface peeling process by the hanging such as the swinging and hitting of the blade inserted into the groove become good, and the production of lightweight cellular concrete with high surface design and design is possible. The present invention has been completed.

That is, the present invention is as follows.
[1] A lightweight cellular concrete having a specific gravity of 0.2 or more and less than 0.45, wherein a ratio of an insoluble residue in the lightweight cellular concrete is 5% by mass or more and less than 20% by mass with respect to a total solid content, and When the particle size of the insoluble residue is less than 10 μm, fine particles, the particle size of 10 μm or more and less than 100 μm are medium particles, and the particle size of 100 μm or more are coarse particles, the content of the coarse particles in the insoluble residue is 2%. A lightweight cellular concrete characterized by being not more than 0.0% by mass.
[2] The lightweight cellular concrete according to [1], wherein a mass ratio of the fine particles to the medium particles (fine particles / medium particles) is 0.75 or more and 1.40 or less.

In the low specific gravity ALC having a specific gravity of 0.2 or more and less than 0.45 according to the present invention, the ratio of the insoluble residue is 5% by mass or more and less than 20% by mass with respect to the total solid content, and the particles of the insoluble residue are When the particles having a diameter of less than 10 μm are fine particles, those having a diameter of 10 μm or more and less than 100 μm are medium particles, and those having a diameter of 100 μm or more are coarse particles, the content of the coarse particles in the insoluble residue is 2.0% by mass or less. With this, fine defects (fine defects) during cutting are reduced, and the ratio of fine particles / medium particles in the insoluble residue is as high as 0.75 or more and 1.40 or less. The surface peeling characteristics with high design and design characteristics due to the swing such as swinging and impact of the surface become good.
Usually, the cutting tool used for the cutting process is worn out, so that the cutting tool is replaced by a new one after cutting about 10,000 m. In addition, usually, in the state of the cutting tool in the initial stage of cutting, there is no particular change in the motor load of the cutting apparatus, but in the latter half of the use after 5,000 to 10,000 m, the motor load increases, and a small defect ( Microdefect) occurs. On the other hand, in the low specific gravity ALC of this embodiment, the wear of the cutting tool at the time of cutting is reduced, and it is possible to use the tool up to 15,000 m.

It is a drawing for explaining the evaluation method of the releasability. It is a schematic diagram of the cutting blade used for cutting. It is a top view of an example of surface separation processing. It is a panel with a stone split tone design that has been peeled off in units of 50 × 100 mm blocks.

  Hereinafter, embodiments for implementing the present invention (hereinafter, referred to as “embodiments”) will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist.

  The lightweight cellular concrete of the present embodiment is a low specific gravity ALC having a specific gravity of 0.2 or more to less than 0.45, and a ratio of an insoluble residue in the low specific gravity ALC is 5% by mass or more and 20% by mass relative to the total solid content. % And the particle size of the insoluble residue is less than 10 μm, the fine particles are 10 μm or more and less than 100 μm, and the coarse particles are 100 μm or more. The content of coarse particles is 2.0% by mass or less, the content of coarse particles in the insoluble residue is preferably 0.5% by mass or less, and the ratio of the insoluble residue is The mass ratio of the fine particles to the medium particles (fine particles / medium particles) is preferably 0.75 or more and 1.40 or less, more preferably 0.75 or more and 1 or less. .20 or less.

If the proportion of the insoluble residue is 5% by mass or more and less than 20% by mass with respect to the total solid content, the motor load increases during machining, in the second half after starting use, and during machining at 5,000 to 10,000 m, and is small during machining. No loss (small loss) occurs.
When the proportion of the insoluble residue is 5% by mass or more, there is no possibility that mass productivity and quality stabilization are impaired. On the other hand, if the ratio of the insoluble residue is less than 20% by mass, the motor load during cutting can be reduced. When the proportion of the insoluble residue is 15% by mass or less, it is preferable from the viewpoint that the increase in the motor load at the time of cutting and the reduction in the occurrence of minute defects can both be achieved.

  If the content of coarse particles in the insoluble residue is 2.0% by mass or less, the motor load increases during cutting, in the second half after use, and during machining at 5,000 to 10,000 m, and small defects ( Minor loss) does not occur.

  When the mass ratio of the fine particles to the medium particles in the insoluble residue (fine particles / medium particles) is 0.75 or more, the releasability is high, and the peelability is good. In addition, it is possible to prevent the peelability from becoming too high (total peeling). For example, in the peelability test described in the section of Examples below, the degree of peeling can be controlled to 60 to 75%. For example, a panel with a stone-tone design as shown in FIG. 3 can be manufactured. However, if the degree of peeling at the time of peeling is about 60 to 75%, it is preferable in terms of design and design. When the degree of peeling is 80% or more, the possibility that the entire surface is peeled (total peeling) increases, and if a part where the whole surface is peeled off occurs, it is not preferable in design.

The (bulk) specific gravity of the low specific gravity ALC of this embodiment is 0.20 or more and less than 0.45, but is preferably 0.23 or more from the viewpoint of obtaining strength suitable as a building material. In addition, the bulk specific gravity is preferably 0.40 or less from the viewpoint of lightness, improvement in safety at the time of on-site work, and an effect of reducing a burden on an operator. In the present specification, “bulk specific gravity” or “specific gravity” refers to bulk specific gravity when dried at 105 ° C. for 24 hours, that is, absolute dry specific gravity.
When the bulk specific gravity or the specific gravity is in this range, the load on the motor during cutting is increased, and the cutting resistance is not excessively increased.

Hereinafter, a method of manufacturing the low specific gravity ALC of the present embodiment will be described.
The method for producing a low specific gravity ALC of the present embodiment is a step of adding metal aluminum powder as a foaming agent to an aqueous slurry containing at least a siliceous raw material, cement and calcareous raw material, injecting it into a mold, pre-curing, and then curing in an autoclave. Containing, as the siliceous raw material, a crystalline siliceous raw material as a main component, fine particles having a particle size of less than 10 μm after pulverization of the crystalline siliceous material, medium particles having a particle size of 10 μm or more and less than 100 μm, and medium particles having a particle size of 100 μm or more. When the coarse particles are used, the content of coarse particles is less than 1.5% by mass, preferably 0.8% by mass or less, and the mass ratio of fine particles to medium particles is 0.75 or more and less than 2.0. It is preferable to use the above-mentioned one.

Further, the ratio of the siliceous raw material, cement and calcareous raw material is preferably 0.5 or more and 1.2 or less as a CaO / SiO ₂ molar ratio. If the CaO / SiO ₂ molar ratio is 0.5 or more, the ratio of the insoluble residue can be made less than 20%. On the other hand, when the molar ratio of CaO / SiO ₂ is 1.2 or less, generation of tobermorite proceeds sufficiently and no quality problem occurs.
As described above, the raw materials used in the production method of the present embodiment generate CaO / from the viewpoint of generating a large amount of tobermorite and sufficiently exhibiting strength, and reducing the insoluble residue to less than 20% by mass. It is more preferable to mix them so that the SiO ₂ molar ratio becomes 0.55 or more. On the other hand, the CaO / SiO ₂ molar ratio is more preferably 1.0 or less, and most preferably 0.8 or less, from the viewpoint of producing a large amount of highly crystalline tobermorite.

In addition, in the total solid raw material in the slurry before being injected into the mold, the content of the aluminum compound in terms of oxide (in terms of Al ₂ O ₃ ) with respect to the content in terms of SO ₃ of the sulfate compound is a mass ratio. It is preferably 0.92 or more and 3 or less. Since the metal aluminum powder used as the foaming agent also acts as an aluminum compound source, it is included as the content of the aluminum compound in terms of oxide (in terms of Al ₂ O ₃ ).

[Silicic raw material]
As the siliceous raw material, for example, crystalline silica stone, silica sand, quartz, and rocks having a high content thereof can be used.
In the present specification, "mainly composed of a crystalline siliceous raw material" means 65 mass% or more, preferably 70 mass% or more, more preferably 80 mass% or more, and further preferably 90 mass%, of the siliceous raw material used. % Or more refers to crystalline silica, quartz sand, quartz, and rocks having a high content thereof.

Among the crystalline siliceous raw materials, among the crystalline siliceous raw materials, a highly crystalline siliceous raw material having a quartz crystal component of 80% by mass or more is preferable. When a large amount of a highly crystalline siliceous raw material having a high quartz crystal component is used, tobermorite produced in low-density and lightweight cellular concrete tends to have high crystallinity.
The proportion of the quartz crystal component in the crystalline siliceous raw material is evaluated using powder X-ray diffraction of the crystalline siliceous raw material. The ratio of the sum of the diffraction intensities of the quartz in the powder X-ray diffraction of the crystalline siliceous raw material to the sum of the diffraction intensities of the quartz observed in the powder X-ray diffraction of the quartz powder is defined as the ratio of the quartz crystal component.

The siliceous raw material used as a raw material of the low specific gravity ALC production method of the present embodiment has fine particles having a particle size of less than 10 μm, fine particles having a particle size of 10 μm or more and less than 100 μm, and medium particles having a particle size of 100 μm or more. When the material is coarse, the content of the coarse particles is preferably less than 1.5% by mass, more preferably 0.8% by mass or less of the total mass of the silica stone and the silica sand. When the content of coarse particles is less than 1.5% by mass, the content of coarse particles in the insoluble residue can be 2.0% by mass or less, preferably 0.5% by mass or less.
When the mass ratio of the fine particles to the medium particles in the pulverized siliceous raw material is 0.75 or more, the mass ratio of the fine particles to the medium particles in the insoluble residue can be 0.75 or more. On the other hand, if the mass ratio of the fine particles to the medium particles in the pulverized siliceous raw material is less than 2.0, the mass ratio of the fine particles to the medium particles in the insoluble residue can be 1.40 or less. More preferably, if the mass ratio of the fine particles to the medium particles in the pulverized siliceous raw material is less than 1.4, the mass ratio of the fine particles to the medium particles in the insoluble residue can be 1.20 or less.

  The particle size and particle size distribution of the crushed silica stone and silica sand can be measured using a laser light diffraction / scattering type particle size distribution meter. The type of measurement is not particularly limited, but may be, for example, a wet measurement. In addition, the measurement range can be set as appropriate, and for example, can be set to 0.12 μm to 704 μm.

[cement]
The cement is not particularly limited, and is mainly composed of a silicate component and a calcium component such as ordinary Portland cement, early-strength Portland cement, and belite cement. However, from the viewpoint of productivity, it is preferable that 30% by mass or more of the cement used is a cement having high hydration reactivity.

[Calcical raw materials]
Calcareous raw materials include quicklime and slaked lime.
In the production method of the present embodiment, the mass ratio of the calcareous raw material to cement is not particularly limited, but is 0.3 or more from the viewpoint of strength, and 1.0 or less from the viewpoint of slurry viscosity and moldability. Is preferred.

[Aluminum compound]
The aluminum compound raw material is not particularly limited, and aluminum sulfate or a hydrate thereof, γ-alumina, aluminum hydroxide, aluminum carbonate, aluminum nitrate, or the like can be used. Aluminum or its hydrate or aluminum hydroxide is preferred. Aluminum metal powder used as a foaming agent for low-density lightweight cellular concrete also acts as an aluminum compound source.

[Sulfuric acid compound (gypsum)]
In the production method of the present embodiment, the amount of the sulfuric acid compound to be contained and the absolute amount of the aluminum compound are not particularly limited, but when the amount of the sulfuric acid compound is small, the generation of tobermorite is delayed, and the pre-curing time is increased. If the amount is too large, it tends to be difficult to obtain an appropriate pore structure, and it is difficult to obtain highly crystalline tobermorite. Therefore, the absolute content of the sulfate compound in the total solid raw material in the slurry before being poured into the mold is preferably 1.5 in terms of SO ₃ , from the viewpoint of processability such as tobermorite generation rate and preliminary curing time. From the viewpoint of obtaining a tobermorite having an appropriate pore structure and high crystallinity, the content is preferably 5% by mass or less, more preferably 1.5 to 4.5% by mass.

The raw material of the sulfate compound used in the production method of the present embodiment is not particularly limited, and may be a compound containing SO ₃ or SO ₄ . For example, alkaline earth metal sulfates such as sulfurous acid, sulfuric acid, anhydrous gypsum (CaSO ₄ ), gypsum dihydrate (CaSO ₄ .2H ₂ O), gypsum hemihydrate (CaSO ₄ .1 / 2H ₂ O), and magnesium sulfate And sulfates of alkali metals such as sodium sulfate, aluminum sulfate (Al ₂ (SO ₄ ) ₃ ) or a hydrate thereof, and metal sulfates such as copper sulfate and silver sulfate. You may use simultaneously. Of these sulfate compound raw materials, gypsum dihydrate, aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), or a hydrate thereof is preferable because the constituent elements are usually included in ALC.

[Bubble agent (foaming agent)]
The foaming agent can be used without particular limitation as long as it can foam a slurry containing a siliceous raw material, a calcareous raw material, and water. For example, metal aluminum powder and the like can be used.

[Water-repellent substance]
The cellular concrete of the present embodiment may contain a water-repellent substance in an amount of 0.1 to 3.0% by mass as necessary. The water-repellent substance is not particularly limited, and includes a siloxane compound, an alkoxysilane compound, a fatty acid, a fatty acid salt, an epoxy resin, a urethane resin, a silicone resin, a vinyl acetate resin, an acrylic resin, and styrene-butadiene. A resin emulsion such as a system resin, etc., of which one kind or a mixture of two or more kinds can be used. Among them, particularly, a siloxane compound, that is, a silicone oil in which a part of the methyl group of polydimethylsiloxane or polydimethylsiloxane is substituted with hydrogen, a phenyl group, a trifluoropropyl group, or the like, an alkoxysilane compound, that is, methyltriethoxysilane, It is preferable to use an alkylalkoxysilane compound such as ethyltriethoxysilane, propyltriethoxysilane, or isobutyltriethoxysilane.

[Other components]
In addition, various materials other than those described above may be appropriately used as long as the desired effects are not affected. For example, reinforcing fibers, surfactants such as methylcellulose, thickeners such as polyacrylic acid and polyvinyl alcohol, water reducing agents, dispersants generally used in cement materials such as high-performance water reducing agents, lignin sulfonic acid, gluconate And a foaming retarder such as a phosphate generally used in cement-based materials.

In the production method of the present embodiment, the method of charging, the charging order, and the mixing time of the siliceous raw material, cement, calcareous raw material, aluminum compound raw material, sulfate compound raw material, alkali compound raw material, and other raw materials are not particularly limited. .
For example, as in the conventional case, the raw materials may be simultaneously charged and mixed for a short time, a surfactant, a metal aluminum powder or a slurry thereof may be added and injected into a mold, or the raw materials may be simultaneously charged and fixed for a certain period of time. After mixing, a surfactant, metallic aluminum powder or a slurry thereof may be added and poured into a mold. Also, for example, following the first step of mixing the siliceous raw material and water and, if necessary, part of the calcareous raw material, the aluminum compound raw material, and the alkali compound raw material, cement, a sulfate compound raw material and the remaining calcareous raw material are added, and further added. After the second step of mixing, a method of adding a foaming agent such as aluminum powder and injecting into a mold may be used. Even when such a method is used, the method at the time of mixing, the temperature at the time of mixing, and the mixing time are not particularly limited.

In the manufacturing method of the present embodiment, it is preferable to form a reinforcing steel bar or a reinforcing wire mesh so as to be buried in cellular concrete similarly to the conventional ALC. Here, the reinforcing bar means a bar in which reinforcing bars are arranged in a desired shape and cross-contacts are welded. The reinforcing wire mesh is formed by processing iron into a net shape, and a lath mesh or the like is a typical example. The shape and dimensions of reinforcing bars or reinforcing wire mesh, the thickness of reinforcing bars, the size of wire mesh, and the position of embedding in lightweight concrete, etc. It is preferable to select as appropriate depending on the size, application, and the like.
It is preferable that these reinforcing steel bars or reinforcing metal meshes have been subjected to a rust preventive treatment effective for durability. Known rust preventives such as synthetic resins can be used. By arranging the reinforcing bar or the wire mesh inside in this manner, the strength at the time of breaking is remarkably improved.

The slurry injected into the mold is pre-cured preferably at 50 to 85 ° C. for one hour or more due to foaming, quick lime and self-heating of cement derived from aluminum powder. The pre-curing is preferably performed in an environment in which moisture is suppressed from evaporating, such as a steam curing room. The obtained pre-cured product is cut into an arbitrary shape as needed, and then cured at high temperature and pressure using an autoclave. For the cutting, a wire cutting method generally used for producing lightweight cellular concrete can also be used. The conditions for the autoclave are preferably from 160 ° C. (gauge pressure: about 5.3 kgf / cm ² ) to 220 ° C. (gauge pressure: about 22.6 kgf / cm ² ).

Hereinafter, the present invention will be described specifically with reference to Examples, but it is needless to say that the present invention should not be construed as being limited to such Examples.
Hereinafter, the raw materials used in Examples and Comparative Examples and various measurement methods will be described.

[(Bulk) specific gravity]
It was calculated from the weight and dimensions when the cured product after autoclaving was dried at 105 ° C. for 24 hours.

[Silicic raw material]
As the siliceous raw material, silica stone or silica sand (A to H) produced from eight mines in Japan and overseas was used.
The method for measuring the particle size of the siliceous raw material after grinding was the same as the method for measuring the particle size of the insoluble residue described below.

[Ratio of insoluble residue to total solids]
The extraction of the insoluble residue was carried out by a method based on the method for quantifying the insoluble residue by the hydrochloric acid-sodium carbonate method described in JIS R5202 Chemical analysis method for Portland cement. The processing that affected the particle size of the residue was changed. Specifically, the separation of the insoluble residue and the filtrate by the filter paper specified in JIS R5202 was changed to the separation by a centrifuge (product name: inverter / tabletop centrifuge type 8400, manufactured by Kubota Seisakusho). Centrifugation conditions were 3000 rpm × 10 minutes. Washing of the insoluble residue with warm water specified in JIS R5202 in the above-described method for quantification was changed to washing with the above-mentioned centrifugal separator, with the amount of warm water being 50 ml. Centrifugation conditions were 3000 rpm × 10 minutes, and the number of washings was five. Further, the strong heat treatment in the electric furnace at 950 ± 25 ° C. × 30 minutes specified in the above-mentioned quantification method of JIS R5202 was changed to a treatment at 110 ° C. × 48 hours by a dryer. Further, the temperature condition of the heat treatment on the water bath specified in the above-mentioned quantification method of JIS R5202 was changed to 80 ° C.
The ratio of the insoluble residue was determined as the mass% of the insoluble residue relative to the weight of the cellular concrete after autoclaving.

[Particle size of insoluble residue]
The particle size distribution of the insoluble residue was measured using a laser diffraction / scattering type particle size distribution meter (product name: Microtrac 9320 HRA X100, manufactured by Nikkiso Co., Ltd.) by a wet method under the following conditions.
Particle size measurement range: 0.12 to 704 μm
Flow rate: 60 ml / sec
Ultrasonic dispersion: 25 watts × 60 sec
Material information: refractive index = 1.54, material = silica (non-spherical particles)
Solvent information: refractive index = 1.33, solvent = water Zero point adjustment time: 30 sec
Measurement conditions: 60 sec x 2 Measurement results: Average of 2 measurements

[Motor load [A] when cutting 5000 to 10000 m]
A cutting blade with a diameter of 9 mm as shown in Fig. 2 was attached to the following electric router as a cutting device, and a motor for forming a linear cutting groove of 5,000 to 10,000 m on the surface of low specific gravity ALC with a groove depth of 9 mm. The load [A] was measured. The length of the formed cutting groove is the total length of the linear cutting grooves formed on a large number of low-specific-gravity ALC panels of a predetermined size. Usually, the cutting tool used for the cutting process is worn out, so that the cutting tool is replaced by a new one after cutting about 10,000 m. In addition, the motor load of the cutting device does not change significantly in the cutting tool state in the initial stage of cutting, but the motor load increases in the latter half of the use after 5,000 to 10,000 m, and small defects (small defects) occur during cutting. ) Occurs. In this example and the comparative example, the motor load at the time of cutting about 7,500 m was measured.
[Electric router]
Motor model: Fuji Electric MVH6107L
Rotation speed: 6000rpm
Feeding speed: 5m / min

[Number of micro defects / m during cutting]
The occurrence rate of micro-defects at the time of cutting at about 7500 m in the measurement of the motor load [A] at the time of cutting at 5000 to 10000 m was evaluated in terms of the number per 1 m of cutting groove.
Here, the “small defect” means a point where the wall of the concave portion and the surface intersect in a cross section when the surface is cut to a groove depth of 9 mm using the cutting blade shown in FIG. ) Indicates a state in which the continuity of a straight line in a plan view is lost due to the corner portion being chipped by 5 mm or more in the straight line direction.

[Peeling degree (%), total peeling (%)]
As shown in FIG. 1, a plate-shaped blade (tip (2)) was inserted into the groove of the cellular concrete panel, and the panel surface was chipped by rocking (prying). The chip width (W) was 50 mm, and the groove depth (D) was 9 mm.
In FIG. 1, the percentage of the area of the chipped panel surface with respect to the panel surface before peeling between the two blades was defined as the peeling degree (%). With the number of samples taken as 100, the average value was determined. The total peeling (%) is the percentage of the number of samples where the panel surface between the two blades has a peeling degree of 100% per 100 samples.
In addition, if the above-mentioned swinging is also performed outside the two blades, for example, a panel having a stone-cut design as shown in FIG. 3 can be manufactured.

[Example 1]
Silica A (quartz crystal component ratio: 75% by mass) and silica B (quartz crystal component ratio: 92% by mass) were each independently pulverized by a mill as a siliceous raw material, and then mixed. Silica powder having a mass ratio of 53% by mass of medium particles having a particle size of 10 μm or more and less than 100 μm and a mass ratio of 47% by mass of fine particles having a particle size of less than 10 μm was obtained. To 92.1 parts by weight of water at 45 ° C. were added 46.3 parts by weight of the silica powder, 2.4 parts by weight of quicklime, 0.47 parts by weight of aluminum hydroxide, and 1.27 parts by weight of potassium alum decahydrate, and mixed and stirred.
Next, 36.1 parts by weight of early-strength Portland cement, 2.0 parts by weight of gypsum dihydrate, 12 parts by weight of quicklime, and an aqueous slurry obtained by previously mixing 0.0095 parts by weight of a surfactant with 2.0 parts by weight of water were added to the aqueous slurry, Further mixing and stirring were performed.
Subsequently, a metal aluminum slurry in which 0.09 part by weight of metal aluminum powder was previously dispersed in 0.72 part by weight of water was charged, stirred, poured into a mold, foamed, and pre-cured. The pre-cured body having a predetermined hardness was placed in an autoclave and autoclaved at 180 ° C. for 4 hours in a saturated steam atmosphere. After removing the can from the autoclave, it was dried to obtain a low-density lightweight concrete. The siliceous raw material, cement and calcareous raw material had a CaO / SiO ₂ molar ratio of 0.78.

[Example 2]
Silica A (quartz crystal component ratio: 75% by mass) and silica C (quartz crystal component ratio: 94% by mass) were each independently pulverized by a mill as a siliceous raw material, and then mixed. By mass%, a ratio of medium grains of 10 μm or more and less than 100 μm was 50.7 mass%, and a ratio of fine grains of less than 10 μm was 49.3 mass% to obtain silica powder. To 92.1 parts by weight of water at 45 ° C. were added 46.3 parts by weight of the silica powder, 2.4 parts by weight of quicklime, 0.47 parts by weight of aluminum hydroxide, and 1.27 parts by weight of potassium alum decahydrate, and mixed and stirred.
Next, to the aqueous slurry, 36.1 parts by weight of early strength Portland cement, 2.0 parts by weight of gypsum dihydrate, 12 parts by weight of quicklime, an aqueous slurry obtained by previously mixing 0.0095 parts by weight of a surfactant with 2.0 parts by weight of water, Mix and stir.
Subsequently, a metal aluminum slurry in which 0.09 part by weight of metal aluminum powder was previously dispersed in 0.72 part by weight of water was charged, stirred, poured into a mold, foamed, and pre-cured. The pre-cured body having a predetermined hardness was placed in an autoclave and autoclaved at 180 ° C. for 4 hours in a saturated steam atmosphere. After removing the can from the autoclave, it was dried to obtain a low-density lightweight concrete. The siliceous raw material, cement and calcareous raw material had a CaO / SiO ₂ molar ratio of 0.78.

[Example 3]
Silica D (quartz crystal component ratio: 82% by mass) and silica C (quartz crystal component ratio: 94% by mass) were each independently pulverized by a mill as a siliceous raw material, and then mixed. By mass%, the ratio of medium particles of 10 μm or more and less than 100 μm was 53.1 mass%, and the ratio of fine particles of less than 10 μm was 46.9 mass% to obtain silica powder. To 92.1 parts by weight of water at 45 ° C., 46.3 parts by weight of the above silica stone powder, 2.4 parts by weight of quicklime, 0.47 parts by weight of aluminum hydroxide, and 1.27 parts by weight of potassium alum decahydrate were added, and mixed and stirred.
Next, to the aqueous slurry, 36.1 parts by weight of early strength Portland cement, 2.0 parts by weight of gypsum dihydrate, 12 parts by weight of quicklime, an aqueous slurry obtained by previously mixing 0.0095 parts by weight of a surfactant with 2.0 parts by weight of water, Mix and stir.
Subsequently, a metal aluminum slurry in which 0.09 part by weight of metal aluminum powder was previously dispersed in 0.72 part by weight of water was charged, stirred, poured into a mold, foamed, and pre-cured. The pre-cured body having a predetermined hardness was placed in an autoclave and autoclaved at 180 ° C. for 4 hours in a saturated steam atmosphere. After removing the can from the autoclave, it was dried to obtain a low-density lightweight concrete. The siliceous raw material, cement and calcareous raw material had a CaO / SiO ₂ molar ratio of 0.78.

[Example 4]
Silica A (quartz crystal component ratio: 75% by mass) is pulverized by a mill as a siliceous material, and the ratio of coarse particles of 100 μm or more is 0% by mass, and the ratio of medium particles of 10 μm or more and less than 100 μm is 39.1% by mass and less than 10 μm. A silica powder having a fine particle ratio of 60.9% by mass was obtained. To 92.1 parts by weight of water at 45 ° C., 46.3 parts by weight of the above silica stone powder, 2.4 parts by weight of quicklime, 0.47 parts by weight of aluminum hydroxide, and 1.27 parts by weight of potassium alum decahydrate were added, and mixed and stirred.
Next, to the aqueous slurry, 36.1 parts by weight of early strength Portland cement, 2.0 parts by weight of gypsum dihydrate, 12 parts by weight of quicklime, an aqueous slurry obtained by previously mixing 0.0095 parts by weight of a surfactant with 2.0 parts by weight of water, Mix and stir.
Subsequently, a metal aluminum slurry in which 0.09 part by weight of metal aluminum powder was previously dispersed in 0.72 part by weight of water was charged, stirred, poured into a mold, foamed, and pre-cured. The pre-cured body having a predetermined hardness was placed in an autoclave and autoclaved at 180 ° C. for 4 hours in a saturated steam atmosphere. After removing the can from the autoclave, it was dried to obtain a low-density lightweight concrete. The siliceous raw material, cement and calcareous raw material had a CaO / SiO ₂ molar ratio of 0.78.

[Example 5]
Silica D (quartz crystal component ratio: 82% by mass) is pulverized by a mill as a siliceous raw material, and the ratio of coarse particles of 100 μm or more is 0% by mass, and the ratio of medium particles of 10 μm to less than 100 μm is 39.1% by mass and less than 10 μm. A silica powder having a fine particle ratio of 60.9% by mass was obtained. To 92.1 parts by weight of water at 45 ° C., 46.3 parts by weight of the above silica stone powder, 2.4 parts by weight of quicklime, 0.47 parts by weight of aluminum hydroxide, and 1.27 parts by weight of potassium alum decahydrate were added, and mixed and stirred.
Next, to the aqueous slurry, 36.1 parts by weight of early strength Portland cement, 2.0 parts by weight of gypsum dihydrate, 12 parts by weight of quicklime, an aqueous slurry obtained by previously mixing 0.0095 parts by weight of a surfactant with 2.0 parts by weight of water, Mix and stir.
Subsequently, a metal aluminum slurry in which 0.09 part by weight of metal aluminum powder was previously dispersed in 0.72 part by weight of water was charged, stirred, poured into a mold, foamed, and pre-cured. The pre-cured body having a predetermined hardness was placed in an autoclave and autoclaved at 180 ° C. for 4 hours in a saturated steam atmosphere. After removing the can from the autoclave, it was dried to obtain a low-density lightweight concrete. The siliceous raw material, cement and calcareous raw material had a CaO / SiO ₂ molar ratio of 0.78.

[Example 6]
Silica A (quartz crystal component ratio: 75% by mass) and silica B (quartz crystal component ratio: 92% by mass) were each independently pulverized by a mill as a siliceous raw material, and then mixed. By mass%, the ratio of medium grains of 10 μm or more and less than 100 μm was 55.1 mass%, and the ratio of fine particles of less than 10 μm was 44.1 mass% to obtain silica powder. To 92.1 parts by weight of water at 45 ° C. were added 46.3 parts by weight of the silica powder, 2.4 parts by weight of quicklime, 0.47 parts by weight of aluminum hydroxide, and 1.27 parts by weight of potassium alum decahydrate, and mixed and stirred.
Next, 36.1 parts by weight of early-strength Portland cement, 2.0 parts by weight of gypsum dihydrate, 12 parts by weight of quicklime, and an aqueous slurry obtained by previously mixing 0.0095 parts by weight of a surfactant with 2.0 parts by weight of water were added to the aqueous slurry, Further mixing and stirring were performed.
Subsequently, a metal aluminum slurry in which 0.09 part by weight of metal aluminum powder was previously dispersed in 0.72 part by weight of water was charged, stirred, poured into a mold, foamed, and pre-cured. The pre-cured body having a predetermined hardness was placed in an autoclave and autoclaved at 180 ° C. for 4 hours in a saturated steam atmosphere. After removing the can from the autoclave, it was dried to obtain a low-density lightweight concrete. The siliceous raw material, cement and calcareous raw material had a CaO / SiO ₂ molar ratio of 0.78.

[Comparative Example 1]
Silica E (quartz crystal component ratio: 81% by mass) and silica F (quartz crystal component ratio: 85% by mass) are mixed 1: 1 as a siliceous raw material, pulverized in a mill, and the ratio of coarse particles of 100 μm or more is 9.4%. %, A ratio of medium particles of 10 μm or more and less than 100 μm was 68.2 mass%, and a ratio of fine particles of less than 10 μm was 22.4 mass%. To 75 parts by weight of water at 45 ° C., 60.8 parts by weight of the silica powder, 7.5 parts by weight of quicklime, 29.2 parts by weight of Portland cement, and 2.5 parts by weight of gypsum dihydrate were mixed and stirred.
Subsequently, a metal aluminum slurry in which 0.06 part by weight of metal aluminum powder was previously dispersed in 0.48 part by weight of water was charged, stirred, poured into a mold, foamed, and pre-cured. The pre-cured body having a predetermined hardness was placed in an autoclave and autoclaved at 180 ° C. for 4 hours in a saturated steam atmosphere. After removing the can from the autoclave, it was dried to obtain a lightweight cellular concrete. The siliceous raw material, cement and calcareous raw material were adjusted to CaO / SiO ₂ molar ratio of 0.45.

[Comparative Example 2]
Silica A (quartz crystal component ratio: 75% by mass) and silica G (quartz crystal component ratio: 75% by mass) were independently pulverized by a mill as a siliceous raw material, and then mixed. In this case, a silica powder having a mass ratio of 56.7% by mass of medium particles having a particle size of 10 μm or more and less than 100 μm and a particle ratio of 41.8% by mass of fine particles having a particle size of less than 10 μm was obtained. To 92.1 parts by weight of water at 45 ° C., 46.3 parts by weight of the above-mentioned silica powder, 2.4 parts by weight of quicklime, 0.47 parts by weight of aluminum hydroxide and 1.27 parts by weight of potassium alum dodecahydrate were added, mixed and stirred.
Next, to the aqueous slurry, 36.1 parts by weight of early strength Portland cement, 2.0 parts by weight of gypsum dihydrate, 12 parts by weight of quicklime, an aqueous slurry obtained by previously mixing 0.0095 parts by weight of a surfactant with 2.0 parts by weight of water, Mix and stir.
Subsequently, a metal aluminum slurry in which 0.09 part by weight of metal aluminum powder was previously dispersed in 0.72 part by weight of water was charged, stirred, poured into a mold, foamed, and pre-cured. The pre-cured body having a predetermined hardness was placed in an autoclave and autoclaved at 180 ° C. for 4 hours in a saturated steam atmosphere. After removing the can from the autoclave, it was dried to obtain a low-density lightweight concrete. The siliceous raw material, cement and calcareous raw material had a CaO / SiO ₂ molar ratio of 0.78.

[Comparative Example 3]
Silica H (quartz crystal component ratio 68% by mass) is pulverized in a mill as a siliceous raw material, and the ratio of coarse particles of 100 μm or more is 13.8% by mass, and the ratio of medium particles of 10 μm or more and less than 100 μm is 43.2% by mass and less than 10 μm. A silica powder having a fine particle ratio of 43.0% by mass was obtained. To 75 parts by weight of water at 45 ° C., 56 parts by weight of this silica powder, 6 parts by weight of quick lime, 36 parts by weight of early strength Portland cement, and 2 parts by weight of gypsum were mixed and stirred.
Subsequently, a metal aluminum slurry in which 0.06 part by weight of metal aluminum powder was previously dispersed in 0.48 part by weight of water was charged, stirred, poured into a mold, foamed, and pre-cured. The pre-cured body having a predetermined hardness was placed in an autoclave and autoclaved at 180 ° C. for 4 hours in a saturated steam atmosphere. After removing the can from the autoclave, it was dried to obtain a lightweight cellular concrete. The siliceous raw material, cement and calcareous raw material were adjusted to 0.53 in a CaO / SiO ₂ molar ratio.

  The evaluation results are shown in Table 1 below.

  In the low specific gravity ALC having a specific gravity of 0.2 or more and less than 0.45 according to the present invention, the ratio of the insoluble residue is 5% by mass or more and less than 20% by mass with respect to the total solid content, and the particles of the insoluble residue are When the particles having a diameter of less than 10 μm are fine particles, those having a diameter of 10 μm or more and less than 100 μm are medium particles, and those having a diameter of 100 μm or more are coarse particles, the content of the coarse particles in the insoluble residue is 2.0% by mass or less. Therefore, the number of fine defects (fine defects) during cutting is small, and the ratio of fine particles / medium particles in the insoluble residue is as high as 0.75 or more and 1.40 or less. Peeling characteristics with high surface design and design properties due to movement such as movement and impact are improved. Therefore, the low specific gravity ALC having a specific gravity of 0.2 to less than 0.45 according to the present invention can be suitably used as an outer wall material, a floor material, an inner wall material, a roof material and the like of a building.

W Chip width D Groove depth 1 Foam concrete 2 Chip (plate-shaped knife)

Claims (2)

  A lightweight cellular concrete having a specific gravity of 0.2 or more and less than 0.45, wherein a ratio of an insoluble residue in the lightweight cellular concrete is 5% by mass or more and less than 20% by mass with respect to a total solid content, and When the particle size is less than 10 μm, the fine particles are 10 μm or more and less than 100 μm, the coarse particles are 100 μm or more, and the content of the coarse particles in the insoluble residue is 2.0 mass%. % Or less.   The lightweight cellular concrete according to claim 1, wherein a mass ratio of the fine grains to the medium grains (fine grains / medium grains) is 0.75 or more and 1.40 or less.

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