JP6949697B2 - Safe room construction panel and its manufacturing method - Google Patents

Description

The present invention relates to a panel for constructing a vault and a method for manufacturing the same.

The walls, ceilings, doors, floors, etc. of the vault are required to have excellent crime prevention (hard to break), fire resistance, and heat insulation.
As a vault with excellent heat insulation, fire resistance, and workability, Patent Document 1 describes at least two synthetic resin foam layers formed by providing a space in the wall structure and the synthetic resin foam layer. A vault is described, characterized in that a concrete layer is provided on each surface side.
Further, Patent Document 2 describes, at least, a vault having a wall structure sandwiched between a front surface and a back surface of a synthetic resin foam layer with a concrete layer.

Japanese Unexamined Patent Publication No. 8-31249 Japanese Unexamined Patent Publication No. 8-312250

In order for the vault to have excellent crime prevention properties, it is necessary to increase the thickness of the walls, ceiling, doors, floors, etc. of the vault, which causes problems such as an increase in cost and a decrease in workability. In addition, when trying to build a vault in an existing structure, it may be difficult to build it due to the problem that the load capacity of the existing floor is insufficient, or a major renovation work of the existing floor is required. There was also the problem that there were cases. Further, if the thickness of the door of the vault is increased, the weight of the door is increased, which causes a problem that it takes time to open and close.
If the panel for constructing the wall, ceiling, door, floor, etc. of the vault has excellent strength (for example, compression strength) and fire resistance, the thickness of the wall, ceiling, door, floor, etc. of the vault, etc. It is convenient to be able to build a vault with excellent security and fire resistance while making the door smaller.
An object of the present invention is to provide a vault construction panel made of a material having high compressive strength and bending strength, and excellent fracture resistance and fire resistance.

As a result of diligent studies to solve the above problems, the present inventor has found cement, ^{silica fume having a BET specific surface area of 15 to 25 m 2} / g, an inorganic powder having a 50% volume cumulative particle size of 0.8 to 5 μm, and maximum grains. A cement composition containing aggregate A having a diameter of 1.2 mm or less, a high-performance water reducing agent, a defoaming agent, a specific metal fiber, an organic fiber, and water, and the composition of the specific material is within a specific numerical range. The present invention has been completed by finding that the above object can be achieved according to the panel for constructing a vault made of the cured product of.

That is, the present invention provides the following [1] to [7].
[1] A panel for constructing a vault made of a hardened cement material, wherein the hardened cement material is cement, ^{a silica fumes having a BET specific surface area of 15 to 25 m 2} / g, and a 50% volume cumulative particle size of 0.8. Inorganic powder of ~ 5 μm, aggregate A with maximum particle size of 1.2 mm or less, high-performance water reducing agent, defoaming agent, metal fiber with diameter of 0.01 to 1.0 mm and length of 2 to 30 mm, organic It is a cured product of a cement composition containing fibers and water, and the ratio of the cement is 55 to 65% by volume and the ratio of the silica fume is 5 to 25 in 100% by volume of the total amount of the cement, the silica fumes and the inorganic powder. By volume%, the proportion of the inorganic powder is 15 to 35% by volume, and the proportion of the metal fibers in the cement composition is more than 3.0% by volume and 4.5% by volume or less. Panel for building a vault.
[2] The above-mentioned [1], wherein the organic fiber is a polypropylene fiber having a diameter of 0.010 to 0.020 mm, a length of 4 to 8 mm, and an aspect ratio (fiber length / fiber diameter) of 300 to 470. Panel for building a vault.
[3] The panel for constructing a vault according to the above [1] or [2], wherein the hardened cementum has a compressive strength of 300 N / mm ^{2 or more.}
[4] The vault construction panel according to the above [1] or [2], wherein the cement composition contains an aggregate B having a maximum particle size of more than 1.2 mm and 13 mm or less.
[5] The panel for constructing a vault according to the above [4], wherein the hardened cementum has a compressive strength of 270 N / mm ^{2 or more.}

[6] The method for manufacturing the vault construction panel according to any one of the above [1] to [5], wherein the cement composition is cast into a mold to form an uncured mold. Molding step to obtain a body and normal temperature curing step to obtain a cured molded body by removing the uncured molded body from the mold after sealing or aerial curing at 10 to 40 ° C. for 24 hours or more. The cured molded product is subjected to either steam curing or hot water curing at 70 ° C. or higher and lower than 100 ° C. for 6 hours or longer, or autoclave curing at 100 to 200 ° C. for 1 hour or longer, or both, and after heat curing. The heat-curing step for obtaining the cured product and the cured product after the heat-curing are heated at 150 to 200 ° C. for 24 hours or more (excluding heating by autoclave curing) to obtain the vault construction panel. A method of manufacturing a panel for building a vault, comprising: obtaining a high temperature heating step.
[7] The method for manufacturing a vault construction panel according to the above [6], which includes a water absorption step of causing the cured molded body to absorb water between the normal temperature curing step and the heat curing step.

The vault construction panel of the present invention has high compressive strength and bending strength (for example, compressive strength: 270 N / mm ² or more, bending strength: 45 N / mm ² or more), and has excellent fracture resistance. Since it is made up of a body, it is possible to reduce the thickness of the vault construction panel to reduce the weight and facilitate the construction of the vault while ensuring excellent crime prevention (hard to break). In addition, the weight of the vault door can be reduced to facilitate its opening and closing.
Further, since the panel for constructing a safe room of the present invention is excellent in fire resistance, it is possible to construct a safe room having excellent fire resistance.

It is a perspective view which shows an example of the laminated panel which combines the panel for building a safe room of this invention, and the heat insulating material. A view showing a flat plate specimen for an impact resistance test using a steel weight ((a): front view of the flat plate specimen, (b): side view of the flat plate specimen; the unit of numerical value is mm). Is.

Vault construction panel of the present invention, there is provided a vault construction panels consisting of cementitious hardened body, cementitious cured product, cement, BET specific surface area of 15~25m 2 / ^g silica fume (hereinafter, "silica fume ”), Inorganic powder with a 50% cumulative particle size of 0.8 to 5 μm (hereinafter, may be abbreviated as“ inorganic powder ”), aggregate with a maximum particle size of 1.2 mm or less. A (hereinafter, may be abbreviated as "aggregate A"), high-performance water reducing agent, defoaming agent, metal fiber having a diameter of 0.01 to 1.0 mm and a length of 2 to 30 mm, organic fiber and It is a cured product of a cement composition containing water, and the proportion of cement is 55 to 65% by volume, the proportion of silica fumes is 5 to 25% by volume, and the inorganic powder in the total amount of cement, silica fumes, and inorganic powder is 100% by volume. The ratio of metal fibers in the cement composition is more than 3.0% by volume and 4.5% by volume or less.
Hereinafter, the cement composition used in the present invention will be described in detail.

The type of cement is not particularly limited, and for example, various Portland cements such as ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, moderate heat Portland cement, sulfate-resistant Portland cement, and low heat Portland cement can be used. Can be used.
Above all, from the viewpoint of improving the fluidity of the cement composition, it is preferable to use moderate heat Portland cement or low heat Portland cement.

The BET specific surface area of silica fume is 15 to 25 m ² / g, preferably 17 to 23 m ² / g, and particularly preferably 18 to 22 m ² / g. When the specific surface area is ^{less than 15 m 2} / g, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are lowered. When the specific surface area ^{exceeds 25 m 2} / g, the fluidity of the cement composition decreases.

Inorganic powders with a 50% cumulative particle size of 0.8 to 5 μm include, for example, quartz powder (silica powder), volcanic ash, and fly ash (classified or crushed), slag powder, limestone powder, and pebbles powder. Examples thereof include mulite powder, alumina powder, silica sol, carbide powder, nitride powder and the like.
One of these may be used alone, or two or more thereof may be used in combination.
Above all, it is preferable to use quartz powder or fly ash from the viewpoint of improving the fluidity of the cement composition and increasing the strength (compression strength and bending strength) and fracture resistance of the hardened cementum.
In the present specification, it is assumed that the inorganic powder having a 50% cumulative particle size of 0.8 to 5 μm does not contain cement.

The 50% volume cumulative particle size of the inorganic powder is 0.8 to 5 μm, preferably 1 to 4 μm, more preferably 1.1 to 3.5 μm, and particularly preferably 1.2 μm or more and less than 3 μm. If the particle size is less than 0.8 μm, the fluidity of the cement composition decreases. When the particle size exceeds 5 μm, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are lowered.
The 50% volume cumulative particle size of the inorganic powder can be determined using a commercially available particle size distribution measuring device (for example, manufactured by Nikkiso Co., Ltd., product name "Microtrack HRA Model 9320-X100").
Specifically, a cumulative particle size curve can be created using a particle size distribution measuring device, and a 50% volume cumulative particle size can be obtained from the cumulative particle size curve. ^{At this time, 0.06 g of the sample was added to 20 cm 3 of} ethanol, which is a solvent for dispersing the sample, and an ultrasonic disperser (for example, manufactured by Nissei Tokyo Office, product name "US300") was used for 90 seconds. Measure the ultrasonic dispersion.

The maximum particle size of the inorganic powder is preferably 15 μm or less, more preferably 14 μm or less, and particularly preferably 13 μm or less, from the viewpoint of increasing the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum. ..
The 95% volume cumulative particle size of the inorganic powder is preferably 8 μm or less, more preferably 7 μm or less, and particularly preferably 6 μm, from the viewpoint of increasing the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum. It is as follows.

As the inorganic powder, _{one containing SiO 2} as a main component (for example, quartz powder) is preferable. _{When the content of SiO 2} in the inorganic powder is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, the strength of the cementum cured product (compression strength and bending strength). And the destruction resistance becomes higher.

In the cement composition, the ratio of cement to 100% by volume of the total amount of cement, silica fume and inorganic powder is 55 to 65% by volume, preferably 57 to 63% by volume. When the ratio is less than 55% by volume, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are lowered. When the ratio exceeds 65% by volume, the fluidity of the cement composition decreases.
The ratio of silica fume to 100% by volume of the total amount of cement, silica fume and inorganic powder is 5 to 25% by volume, preferably 7 to 23% by volume. When the ratio is less than 5% by volume, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are lowered. When the ratio exceeds 25% by volume, the fluidity of the cement composition decreases.
The ratio of the inorganic powder to 100% by volume of the total amount of cement, silica fume and the inorganic powder is 15 to 35% by volume, preferably 17 to 33% by volume. When the ratio is less than 15% by volume, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are lowered. When the ratio exceeds 35% by volume, the fluidity of the cement composition decreases.

The aggregate A includes river sand, land sand, sea sand, crushed sand, silica sand, natural emery sand, artificial fine aggregate (for example, slag fine aggregate, fired fine aggregate obtained by firing fly ash, etc., and artificial fine aggregate. Examples thereof include (artificial) emery sand, coarsely pulverized products of alumina or carbides (for example, silicon carbide, boron carbide, etc.), recycled fine aggregates, or mixtures thereof.
The maximum particle size of the aggregate A is 1.2 mm or less, preferably 1.1 mm or less, and particularly preferably 1.0 mm or less. When the maximum particle size is 1.2 mm or less, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are high.
The particle size distribution of the aggregate A is such that the particle size of the aggregate A is 0.6 mm or less from the viewpoint of improving the fluidity of the cement composition and increasing the strength (compression strength and bending strength) and fracture resistance of the hardened cement material. The proportion of aggregates having a particle size of 95% by mass or more and 0.3 mm or less is 40 to 50% by mass, and the proportion of aggregates having a particle size of 0.15 mm or less is 6% by mass or less. Is preferable.
The proportion of aggregate A in the cement composition is preferably 20-40% by volume, more preferably 22-38% by volume, even more preferably 30-37% by volume, and particularly preferably 32-36% by volume. When the ratio is 20% by volume or more, the calorific value of the cement composition becomes small and the shrinkage amount of the cementum cured product becomes small. When the ratio is 40% by volume or less, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are higher.

As the high-performance water-reducing agent, a high-performance water-reducing agent such as naphthalene sulfonic acid-based, melamine-based, or polycarboxylic acid-based can be used. Above all, a polycarboxylic acid-based high-performance water reducing agent is preferable from the viewpoint of improving the fluidity of the cement composition and increasing the strength (compression strength and bending strength) and fracture resistance of the cementum cured product.
The blending amount of the high-performance water reducing agent is preferably 0.2 to 1.5 parts by mass, more preferably 0.4 in terms of solid content, with respect to 100 parts by mass of the total amount of cement, silica fume and inorganic powder. ~ 1.3 parts by mass. When the amount is 0.2 parts by mass or more, the water reduction performance is improved and the fluidity of the cement composition is improved. When the amount is 1.5 parts by mass or less, the strength (compressive strength and bending strength) and fracture resistance of the cementum cured product become higher.

As the defoaming agent, a commercially available product can be used.
The amount of the defoaming agent to be blended is preferably 0.001 to 0.1 parts by mass, more preferably 0.01 to 0.07 parts by mass, particularly based on 100 parts by mass of the total amount of cement, silica fume and inorganic powder. It is preferably 0.01 to 0.05 parts by mass. When the amount is 0.001 part by mass or more, the strength development of the cement composition is improved. When the amount exceeds 0.1 parts by mass, the effect of improving the strength development of the cement composition reaches a plateau.

Examples of the metal fiber include steel fiber, stainless steel fiber, amorphous fiber and the like. Among them, steel fiber is excellent in strength, and is suitable from the viewpoint of cost and availability.
The dimensions of the metal fibers are 0.01 to 1.0 mm in diameter and length from the viewpoint of preventing material separation of the metal fibers in the cement composition and increasing the bending strength and fracture resistance of the hardened cement material. Is preferably 2 to 30 mm, more preferably 0.05 to 0.5 mm in diameter and 5 to 25 mm in length. The aspect ratio (fiber length / fiber diameter) of the metal fiber is preferably 20 to 200, more preferably 40 to 150.
Further, the shape of the metal fiber is preferably a shape (for example, a spiral shape or a corrugated shape) that imparts some physical adhesive force rather than a linear shape. If the shape is spiral or the like, the metal fiber and the matrix secure stress while pulling out, so that the bending strength and fracture resistance of the hardened cementum are increased.
The proportion of metal fibers in the cement composition is greater than 3.0% by volume and less than 4.5% by volume, preferably 3.2 to 4.2% by volume, more preferably 3.3 to 3.7% by volume. Is. When the ratio is 3.0% by volume or less, the bending strength and fracture resistance of the hardened cementum are lowered. When the ratio exceeds 4.5% by volume, the fluidity and workability of the cement composition are significantly lowered.

Examples of the organic fiber include aramid fiber, polyparaphenylene benzobisoxazole fiber, polyethylene fiber, polyarite fiber, polypropylene fiber, polyvinyl alcohol fiber and the like. Of these, polypropylene fiber is preferable from the viewpoint of easy availability and improvement of fire resistance of the hardened cementum.
The dimensions of the organic fibers are 0.005 to 1.000 mm in diameter and 2 to 30 mm in length from the viewpoint of preventing material separation of the organic fibers in the cement composition and improving the fire resistance of the hardened cement material. The diameter is 0.008 to 0.500 mm and the length is 4 to 25 mm, and the diameter is 0.010 to 0.030 mm and the length is 4 to 10 mm. Is more preferable, and it is particularly preferable that the diameter is 0.012 to 0.020 mm and the length is 4 to 8 mm.

The aspect ratio (fiber length / fiber diameter) of the organic fiber is preferably 20 to 500, more preferably 30 to 490, still more preferably 200 to 480, still more preferably 230 to 470, and particularly preferably 300 to 450. be.
Among them, polypropylene fibers having a diameter of 0.010 to 0.030 mm, a length of 4 to 10 mm, and an aspect ratio (fiber length / fiber diameter) of 230 to 480, from the viewpoint of further improving the fire resistance of the hardened cement material. Is preferable, polypropylene fibers having a diameter of 0.010 to 0.020 mm, a length of 4 to 8 mm, and an aspect ratio (fiber length / fiber diameter) of 300 to 470 are more preferable, and a diameter of 0.012 to 0.020 mm is preferable. Polypropylene fibers having a length of 4 to 8 mm and an aspect ratio (fiber length / fiber diameter) of 300 to 450 are particularly preferable.
The proportion of organic fibers in the cement composition is preferably 0.01-0.5% by volume, more preferably 0.03 to 0.4% by volume, even more preferably 0.05 to 0.3% by volume, further. It is preferably 0.07 to 0.25% by volume, and particularly preferably 0.09 to 0.2% by volume. When the ratio is 0.01% by volume or more, the fire resistance of the hardened cementum is further improved. When the ratio is 0.5% by volume or less, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are higher.

As water, tap water or the like can be used.
The blending amount of water is preferably 10 to 20 parts by mass, more preferably 11 to 18 parts by mass, and particularly preferably 14 to 16 parts by mass with respect to 100 parts by mass of the total amount of cement, silica fume and inorganic powder. When the amount is 10 parts by mass or more, the fluidity of the cement composition is improved. When the amount is 20 parts by mass or less, the strength (compressive strength and bending strength) and fracture resistance of the cementum cured product become higher.

The flow value of the mortar composed of the above cement composition (which does not contain aggregate B described later) before curing is 15 times in the method described in "JIS R 5201 (Physical test method for cement) 11. Flow test". The value measured without the falling motion (hereinafter, also referred to as “0 stroke flow value”) is preferably 150 mm or more, more preferably 155 mm or more, and particularly preferably 160 mm or more.
When the flow value is 150 mm or more, workability when manufacturing a panel for constructing a safe room can be improved.
Further, the compressive strength of the hardened cement material obtained by curing a mortar composed of the above cement composition (which does not contain aggregate B described later) is preferably 300 N / mm ² or more, more preferably 320 N / mm ² or more. , more preferably 330N / mm ² or more, more preferably 350 N / mm ² or more, more preferably 370N / mm ² or more, and particularly preferably 400 N / mm ² or more.

The aggregate A having a modified Mohs hardness of 9 or more (preferably 9 to 14, more preferably 10 to 13, particularly preferably 11 to 13) (for example, natural or artificial (artificial) emery sand, According to a mortar made of a cement composition using (such as coarsely pulverized alumina or carbide), the compressive strength of the hardened cementum can be 400 N / mm ² or more. can. In particular, according to natural or artificial (artificial) emery sand, the compressive strength of the hardened cementum can be 430 N / mm ² or more.

The cement composition of the present invention can contain an aggregate B having a maximum particle size of more than 1.2 mm and 13 mm or less.
The aggregate B is a fired fine aggregate obtained by firing river sand, mountain sand, land sand, sea sand, crushed sand, silica sand, natural emery sand, artificial fine aggregate (for example, slag fine aggregate, fly ash, etc.). , Artificial (artificial) emery sand), recycled fine aggregate, river gravel, mountain gravel, land gravel, crushed stone, artificial coarse aggregate (for example, slag coarse aggregate, fly ash, etc. Materials), recycled coarse aggregates, coarsely ground alumina or carbides (eg, silicon carbide, boron carbide, etc.), or mixtures thereof.
The maximum particle size of the aggregate B is 13 mm or less, preferably 12 mm or less, more preferably 11 mm or less, and particularly preferably 10 mm or less. When the maximum particle size is 13 mm or less, the strength development of the cement composition is improved, and for example, ^{a compressive strength of 270 N / mm 2} or more can be exhibited.
The maximum particle size of the aggregate B is a value exceeding 1.2 mm from the viewpoint of cost reduction and the like, preferably 3 mm or more, more preferably 5 mm or more, and particularly preferably 7 mm or more.
In the present specification, the "maximum particle size" when the maximum particle size of the aggregate B is 5 mm or more is the nominal size of the sieve having the smallest size among the sieves through which 90% by mass or more of the entire aggregate B passes. Refers to the particle size of the aggregate B indicated by (generally known as the definition of the maximum particle size of the coarse aggregate).

The minimum particle size of the aggregate B is preferably a value exceeding the maximum particle size of the aggregate A, more preferably 2 mm or more, further preferably 3 mm or more, still more preferably 4 mm or more, and particularly preferably 5 mm or more (in this case). , Corresponds to coarse aggregate.)
In the present specification, the minimum particle size of the aggregate B is the entire aggregate B when the particle size of the aggregate B is accumulated from the smallest particle size to the larger particle size. It refers to the particle size of the aggregate B when it reaches 15% by mass.

In the present invention, the ratio of the total amount of the aggregate A and the aggregate B in the cement composition is preferably 25 to 40% by volume, more preferably 28 to 38% by volume, and particularly preferably 30 to 36% by volume. .. When the ratio is 25% by volume or more, the calorific value of the cement composition becomes small and the shrinkage amount of the cementum cured product becomes small. When the ratio is 40% by volume or less, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
The ratio of the aggregate B to the total amount of the aggregate A and the aggregate B is preferably 40% by volume or less, more preferably 30% by volume or less, and particularly preferably 25% by volume or less. When the ratio is 40% by volume or less, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
Compressive strength of the aggregate cement composition comprising a B (e.g., concrete) cementitious cured body obtained by curing is preferably 270N / mm ² or more, more preferably 280N / mm ² or more, more preferably 290 N / mm ² or more, more preferably 300N / mm ² or more, more preferably 310N / mm ² or more, and particularly preferably 315N / mm ² or more.

Hereinafter, a method for manufacturing a vault construction panel made of a hardened cementum obtained by hardening the above-mentioned cement composition will be described in detail.
An example of the method for manufacturing a panel for constructing a vault of the present invention is a molding step of casting the above-mentioned cement composition into a mold to obtain an uncured molded product, and 10 to 10 uncured molded products. A room temperature curing step of obtaining a cured molded product by removing the mold from the mold after sealing or aerial curing at 40 ° C. for 24 hours or more, and a cured molded product at 70 ° C. or higher and lower than 100 ° C. for 6 hours or longer. A heat curing step of obtaining a cured product after heat curing and a cured product after heat curing by performing either or both of steam curing or hot water curing and autoclave curing at 100 to 200 ° C. for 1 hour or more, and 150 It includes a high-temperature heating step of heating at ~ 200 ° C. for 24 hours or more (excluding heating by autoclave curing) to obtain a panel for constructing a vault made of a hardened cement material.

[Molding process]
This step is a step of casting the cement composition into the mold to obtain an uncured molded product.
The method of kneading the cement composition before casting is not particularly limited. Further, the apparatus used for kneading is not particularly limited, and a conventional mixer such as an omni mixer, a pan-type mixer, a biaxial kneading mixer, and a tilting mixer can be used. Further, the casting (molding) method is not particularly limited.
The uncured molded product in this step may consist of a cement composition in which air bubbles in the cement composition are reduced or removed. By reducing or removing air bubbles in the cement composition, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
As a method for reducing or removing air bubbles in the cement composition, (1) a method of kneading the cement composition under reduced pressure, and (2) before placing the kneaded cement composition in a mold. Examples thereof include a method of defoaming by reducing the pressure, and (3) a method of placing the cement composition in a mold and then defoaming by reducing the pressure.

[Normal temperature curing process]
In this step, the uncured molded product is sealed or cured in air at 10 to 40 ° C. (preferably 15 to 30 ° C.) for 24 hours or more (preferably 24 to 72 hours, more preferably 24 to 48 hours). This is a step of removing the mold from the mold to obtain a cured molded product.
When the curing temperature is 10 ° C. or higher, the curing time can be shortened. When the curing temperature is 40 ° C. or lower, the strength (compression strength and bending strength) and fracture resistance of the cementum cured product (safe room construction panel) can be further increased.
If the curing time is 24 hours or more, defects such as chips and cracks are less likely to occur in the cured molded product during demolding.
Further, in this step, when the cured molded product ^{exhibits a compressive strength of preferably 20 to} 100 N / mm 2, more preferably 30 to 80 N / mm ² , the cured molded product is removed from the mold. Is preferable. When the compressive strength is 20 N / mm ² or more, defects such as chips and cracks are less likely to occur in the cured molded product during demolding. When the compressive strength is 100 N / mm ² or less, the cured molded product can be made to absorb water with less labor in the water absorption step described later.

[Heat curing process]
In this step, the cured molded product obtained in the previous step is steam-cured or hot-water-cured at 70 ° C. or higher and lower than 100 ° C. (preferably 75-95 ° C., more preferably 80-92 ° C.) for 6 hours or longer. This is a step of performing one or both of autoclave curing at 100 to 200 ° C. (preferably 160 to 190 ° C.) for 1 hour or more to obtain a cured product after heat curing.
When only steam curing or hot water curing is performed in this step, the curing time is preferably 24 hours or more, more preferably 24-96 hours, and particularly preferably 36-72 hours. When only autoclave curing is performed, the curing time is preferably 8 to 60 hours, more preferably 12 to 48 hours. When performing both steam curing or hot water curing and autoclave curing (for example, when performing steam curing or hot water curing and then autoclave curing), the curing time in steam curing or hot water curing is preferably 6 to 72 hours. , More preferably 12 to 48 hours, and the curing time in autoclave curing is preferably 1 to 24 hours, more preferably 4 to 18 hours.
In this step, if the curing temperature is within the above range, the curing time can be shortened, and the strength (compression strength and bending strength) and fracture resistance of the cementum cured product can be further increased.
Further, in this step, if the curing time is within the above range, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.

[High temperature heating process]
In this step, the cured product after heat curing is heated at 150 to 200 ° C. (preferably 170 to 190 ° C.) for 24 hours or more (preferably 24 to 72 hours, more preferably 36 to 48 hours) and heated (however, autoclave). This is a step of obtaining a panel for constructing an autoclave made of a hardened cement material obtained by curing the cement composition by (excluding heating by curing).
The heating in this step is usually performed in a dry atmosphere (in other words, in a state where water or water vapor is not artificially supplied).
When the heating temperature is 150 ° C. or higher, the heating time can be shortened. When the heating temperature is 200 ° C. or lower, the strength (compression strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
When the heating time is 24 hours or more, the strength (compression strength and bending strength) and fracture resistance of the hardened cementum can be further increased.

[Water absorption process]
Between the normal temperature curing step and the heat curing step, a water absorption step of causing the cured molded product obtained in the normal temperature curing step to absorb water may be included.
Examples of the method of allowing the cured molded product to absorb water include a method of immersing the molded product in water. Further, in the method of immersing the molded body in water, from the viewpoint of increasing the amount of water absorption in a short time and increasing the strength (compression strength and bending strength) and fracture resistance of the cementified cured product, (1) the molded body. (2) The molded body is immersed in boiling water, and then the water temperature is lowered to 40 ° C. or lower while the molded body is immersed. (3) A method of immersing the molded body in boiling water, then removing the molded body from the boiling water, and then immersing the molded body in water at 40 ° C. or lower. 4) Immerse the molded body in water under pressure, or (5) Immerse the molded body in an aqueous solution in which a chemical that improves the permeability of water into the molded body is dissolved. The method is preferred.

Examples of the method of immersing the molded body in water under reduced pressure include a method of using equipment such as a vacuum pump and a large decompressing container.
Examples of the method of immersing the molded product in boiling water include a method of using equipment such as a high-temperature and high-pressure container and a hot and hot water tank.
The time for immersing the cured molded product in water under reduced pressure or boiling water is preferably 3 minutes or longer, more preferably 8 minutes or longer, and particularly preferably 20 minutes, from the viewpoint of increasing the water absorption rate. That is all. The upper limit of the time is preferably 60 minutes, more preferably 45 minutes from the viewpoint of increasing the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum.

The water absorption rate in the water absorption step is determined when the cement composition does not contain coarse aggregate (when the cement composition does not contain aggregate B or when aggregate B in the cement composition does not correspond to coarse aggregate). The ratio of water to 100% by volume of the cured compact of φ50 × 100 mm is preferably 0.20% by volume or more, more preferably 0.30 to 2.0% by volume, and further preferably 0.35 to 1.5 volumes. %, More preferably 0.36 to 1.0% by volume, particularly preferably 0.37 to 0.80% by volume, and the cement composition contains coarse aggregate (aggregate in the cement composition). (When B corresponds to a coarse aggregate), the ratio of water to 100% by volume of the cured compact of φ100 × 200 mm is preferably 0.20% by volume or more, more preferably 0.30 to 2.0% by volume. It is more preferably 0.35 to 1.5% by volume, further preferably 0.36 to 1.0% by volume, and particularly preferably 0.37 to 0.80% by volume.
When these water absorption rates are 0.20% by volume or more, the strength (compression strength and bending strength) and fracture resistance of the hardened cementum can be further increased.

Since the panel for constructing a vault of the present invention is made of a hardened cementum having high compressive strength, it is less likely to crack and has excellent crime prevention properties. Further, the thickness of the vault construction panel made of the hardened cementum can be reduced while having sufficient crime prevention properties. As a result, the weight of the safe room construction panel can be reduced, the safe room construction can be facilitated, and the workability can be improved. Further, since the weight of the door of the safe room (using the panel for constructing the safe room of the present invention) can be reduced, opening and closing of the door can be facilitated.
Further, the vault construction panel of the present invention is excellent in fire resistance.

Further, the panel for constructing a safe room of the present invention is excellent in dimensional stability. When a 40 x 40 x 160 mm specimen measured in accordance with "JIS A 1129-2: 2010 (Mortar and concrete length change measurement method-Part 2: Contact gauge method)" is stored for 6 months. The shrinkage strain of the hardened cementum is preferably 10 × 10 ^-6 or less, more preferably 8 × 10 ^-6 or less, and particularly preferably 6 × 10 ^-6 or less.
Further, the vault construction panel of the present invention has a large bending strength. The bending strength of the hardened cement material measured in accordance with "JSCE-G 552-2010 (Bending strength and bending toughness test method of steel fiber reinforced concrete)" is preferably 45 N / mm ² or more. preferably 48N / mm ² or more, more preferably 50 N / mm ² or more, and particularly preferably 53N / mm ² or more.
Further, the vault construction panel of the present invention is excellent in fracture resistance (impact resistance).

The shape of the vault construction panel of the present invention is not particularly limited, and may be appropriately determined according to the shape of the vault constructed using the panel. For example, from the viewpoint of versatility, it may have a rectangular (square or rectangular) plate shape, or may have a stepped portion according to the shape of a vault door or the like.
Further, from the viewpoint of improving the fire resistance and the heat insulating property of the safe room, it is preferable to use a member (laminated panel) formed by combining the safe room construction panel and the heat insulating material for the construction of the safe room.
Hereinafter, an example of a laminated panel formed by combining a safe room construction panel and a heat insulating material will be described with reference to FIG.

The laminated panel 1 is a heat insulating material (heat insulating layer; heat insulating plate) 4, a vault construction panel 3 and 5 of the present invention fixed to both sides of the heat insulating material 4, and an exterior material fixed to one side of the panel 3 (a heat insulating material). It is composed of a member (member on the outdoor side) 2 and an interior material (member on the indoor side) 6 fixed to one side of the panel 5.
Examples of the material of the heat insulating material 4 include calcium silicate, rock wool, and synthetic resin foam. When the laminated panel 1 has the heat insulating material 4, the fire resistance and the heat insulating property of the safe room are further improved.
The thickness of the heat insulating material 4 is not particularly limited, but is preferably 20 mm or more, more preferably 30 mm or more from the viewpoint of fire resistance and heat insulating property of the safe room, and from the viewpoint of workability. It is preferably 200 mm or less, more preferably 150 mm or less.
The safe room construction panels 3 and 5 are preferably arranged on both sides of the heat insulating material 4 from the viewpoint of improving crime prevention, but may be arranged on only one of the surfaces.
The thickness of the vault construction panels 3 and 5 is not particularly limited, but from the viewpoint of improving crime prevention, it is preferably 20 mm or more, more preferably 25 mm or more, and particularly preferably 30 mm or more. From the viewpoint of improving workability by weight reduction, it is preferably 100 mm or less, more preferably 90 mm or less, and particularly preferably 80 mm or less.

The exterior material 2 is fixed to the vault construction panel 3 which is the outside of the vault when the vault is constructed, for the purpose of improving the security of the vault and improving the appearance.
The interior material 6 is fixed to the vault construction panel 5 which is inside the vault when the vault is constructed for the purpose of improving the crime prevention property and the appearance of the vault.
As the exterior material 2 and the interior material 6, exterior materials and interior materials generally used in buildings, houses, and the like can be used.
Further, from the viewpoint of improving the crime prevention property, a layer made of a metal plate (not shown in FIG. 1) may be provided between the heat insulating material 4 and the safe room construction panels 3 and 5.
Examples of the material of the exterior material 2, the interior material 6, and the metal plate include iron, aluminum, copper, stainless steel, titanium, and steel.
Each member (constituent member of the laminated panel 1) such as a safe room construction panel is fixed to each other by using an adhesive such as epoxy resin or bolts.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.
[Material used]
The materials used are as shown below.
(1) Cement: Low-grade Portland cement (manufactured by Taiheiyo Cement)
(2) Silica fume: BET specific surface area 20 m ² / g
(3) Inorganic powder: silica stone powder, 50% volume cumulative particle size 2 μm, maximum particle size 12 μm, 95% volume cumulative particle size 5.8 μm
(4) Aggregate A (fine aggregate): Silica sand (maximum particle size 1.0 mm, particle size of 0.6 mm or less: 98% by mass, particle size of 0.3 mm or less: 45% by mass, 0 .15 mm or less particle size: 3% by mass)
(5) Polycarboxylic acid-based high-performance water reducing agent: Solid content 27.4% by mass, manufactured by Floric, trade name "Floric SF500U"
(6) Defoamer: Made by BASF Japan, trade name "Master Air 404"
(7) Water: Tap water (8) Metal fiber: Steel fiber (diameter: 0.2 mm, length: 15 mm)
(9) Organic fiber: Polypropylene fiber (diameter: 0.014 mm, length: 6 mm, aspect ratio: 429)
(10) Aggregate B (coarse aggregate): Hard sandstone crushed stone 1005 (grain size: 5 to 10 mm)

[Example 1]
Cement, silica fume and inorganic powder were mixed so that each ratio of cement and the like was as shown in Table 1 in 100% by volume of the total amount of the powder raw materials (cement, silica fume and inorganic powder). The obtained mixture and the amount of the aggregate A in which the ratio of the aggregate A in the cement composition was the ratio shown in Table 1 were put into an omnimixer and kneaded for 15 seconds.
Next, water, a polycarboxylic acid-based high-performance water reducing agent, and a defoaming agent were added to the omnimixer in the amounts shown in Table 1 and kneaded for 2 minutes.
After kneading, the kneaded material adhering to the side wall in the omnimixer was scraped off, and kneading was further carried out for 4 minutes.
Then, the amount of the fiber whose ratio of the metal fiber and the organic fiber in the cement composition became the ratio shown in Table 1 was put into the omnimixer, and kneaded for another 2 minutes.
The flow value of the cement composition after kneading was measured in the method described in "JIS R 5201 (Physical test method for cement) 11. Flow test" without performing 15 falling motions. In addition, in this specification, the flow value is referred to as "0 stroke flow value".

The obtained kneaded product was cast into a cylindrical mold having a diameter of 50 × 100 mm to obtain an uncured molded product. After casting, the uncured molded product was sealed and cured at 20 ° C. for 48 hours, and then demolded to obtain a cured molded product. The compressive strength at the time of demolding was 43 N / mm ² .
This molded product was immersed in water for 30 minutes in a depressurized desiccator (indicated as "under reduced pressure" in Table 2). The depressurization was performed using an "Aspirator (AS-01)" manufactured by AS ONE. The mass of the molded product before and after immersion was measured, and the water absorption rate was calculated from the obtained measured values.
After the immersion, the molded product was steam-cured at 90 ° C. for 48 hours, then lowered to 20 ° C., and then heated at 180 ° C. for 48 hours.
The compressive strength of the molded product (hardened cementum) after heating was measured according to "JIS A 1108 (concrete compressive strength test method)".
Further, the bending strength of the molded body (hardened cement material) after heating was measured according to "JSCE Standard JSCE-G 552-2010 (Bending strength and bending toughness test method of steel fiber reinforced concrete)".

Further, the heated molded body (cementized hardened body) was heated using a refractory furnace, and the fire resistance when heated for 60 minutes and the fire resistance when heated for 180 minutes were evaluated. The heating was performed for a predetermined time (60 minutes or 180 minutes) according to the heating curve defined in "ISO834", and after heating, it was naturally cooled. The maximum temperature in the above heating was 900 ° C. when heated for 60 minutes and 1,100 ° C. when heated for 180 minutes.
The fire resistance of the cooled molded product (cementum-hardened product) was evaluated using the presence or absence of explosion, the mass reduction rate, and the residual compressive strength, with particular emphasis on the presence or absence of explosion. The smaller the explosion, the smaller the mass reduction rate, and the larger the residual compressive strength, the better the fire resistance.

Further, a flat plate specimen having a length of 550 mm, a width of 100 mm, and a thickness of 25 mm was produced in the same manner as the molded product (cementum cured product) after heating.
As shown in FIG. 2, a steel weight 12 (mass 20 kg, tip diameter 200 mm) is placed in the center of the flat plate specimen 11, the first time is 10 cm, the second time is 20 cm, the third time is 30 cm, and so on. By increasing the drop height by 10 cm and free-falling each time (for example, the fifth free-fall is performed from a height of 50 cm), repeated loading is applied, and the flat plate specimen is dropped at any number of times. The number of times that 11 broke was measured.
The impact resistance of the hardened cementum was evaluated using the obtained number of times. The greater the number of times, the better the impact resistance.
Table 2 shows the evaluation (number of times) of 0-strike flow value, water absorption rate, compressive strength, bending strength, fire resistance and impact resistance. In Table 2, "◎" indicates that the fire resistance is extremely excellent (the crack width of the molded product after cooling is less than 1 mm), and "○" is excellent in fire resistance (after cooling). The crack width of the molded product is 1 mm or more and less than 10 mm), and "x" indicates that the fire resistance is inferior (the crack width of the molded product after cooling is 10 mm or more and there is peeling). ..
Table 2 also shows the 0-stroke flow values and the like in Examples and Comparative Examples described later.

[Example 2]
The cement composition and cementum hardening were carried out in the same manner as in Example 1 except that the blending amount of the polycarboxylic acid-based high-performance water reducing agent was changed to 0.95 parts by mass and the blending ratio of the metal fiber was changed to 3.5% by volume. I got a body. The compression strength at the time of demolding was 43 N / mm ² .
Further, in the same manner as the molded body (cementated hardened body) after heating, a test piece having a size of 40 × 40 × 160 mm was produced, and “JIS A 1129-2: 2010 Method for Measuring Length Change of Mortar and Concrete-No. When the shrinkage strain was measured when stored for 6 months in accordance with "Part 2: Contact Gauge Method", the shrinkage strain was 3 × ^10-6 .
Furthermore, the durability of "ASTM C666 75" is used with respect to the molded product (cementum cured product) after heating, using the values measured in accordance with "JIS A 1148 (freezing and thawing test method for concrete)". When the index (300 cycles) was calculated, the durability index was 100.
The durability index has a maximum value of 100, and the closer to the maximum value, the better the freeze-thaw resistance.

[Example 3]
The cement composition and cementum hardening were carried out in the same manner as in Example 1 except that the blending amount of the polycarboxylic acid-based high-performance water reducing agent was changed to 0.98 parts by mass and the blending ratio of the metal fiber was changed to 4.0% by volume. I got a body. The compression strength at the time of demolding was 44 N / mm ² .
[Example 4]
A cement composition and a hardened cementum were obtained in the same manner as in Example 2 except that the molded product after demolding was immersed in boiling water instead of being immersed in water in a depressurized desiccator. The compression strength at the time of demolding was 43 N / mm ² .

[Example 5]
In 100% by volume of powder raw material, the blending ratio of silica fume and inorganic powder is 20% by volume, the blending amount of polycarboxylic acid-based high-performance water reducing agent is 0.94 parts by volume, and the blending ratio of metal fibers is 3.5% by volume. A cement composition and a cementified hardened product were obtained in the same manner as in Example 4 except for the modification. The compression strength at the time of demolding was 47 N / mm ² .
Further, in the same manner as in Example 2, the shrinkage strain was measured and the durability index was calculated. As a result, the shrinkage strain was 4 × ^10-6 , and the durability index was 100.
[Example 6]
In 100% by volume of powder raw material, 20% by volume of silica fume and inorganic powder, 0.86 parts by mass of polycarboxylic acid-based high-performance water reducing agent, and 3.5% by volume of metal fiber. In the same manner as in Example 4, except that the amounts of the aggregate A and the aggregate B in the cement composition having the ratio shown in Table 1 are added to the omnimixer. , Cement composition was obtained. Next, a cementum hardened product was obtained in the same manner as in Example 4 except that the obtained cement composition (kneaded product) was cast into a cylindrical mold having a diameter of 100 × 200 mm. The compression strength at the time of demolding was 35 N / mm ² .

[Comparative Example 1]
Example 1 except that the blending amount of the polycarboxylic acid-based high-performance water reducing agent was changed to 0.83 parts by volume, the blending ratio of the metal fiber was changed to 2.0% by volume, and the blending ratio of the organic fiber was changed to 0.2% by volume. In the same manner as above, a cement composition and a hardened cement material were obtained. The compression strength at the time of demolding was 44 N / mm ² .
With respect to the cement compositions obtained in Examples 2 to 5 and Comparative Example 1, the zero-strike flow value of the cement composition was measured in the same manner as in Example 1.
[Comparative Example 2]
The cement composition and cementum hardening were carried out in the same manner as in Example 1 except that the blending amount of the polycarboxylic acid-based high-performance water reducing agent was changed to 1.20 parts by mass and the blending ratio of the metal fiber was changed to 5.0% by volume. I got a body.
In the same manner as in Example 1, the zero-strike flow value of the cement composition was measured.
Moreover, since the obtained cement composition had poor fluidity and workability, it could not be molded.

From Table 2, it can be seen that the compressive strength of the cementum hardened body (those not containing aggregate B) in Examples 1 to 5 is 403 N / mm ² or more, which is very large.
Further, it can be seen that the compressive strength of the cementum hardened body (including the aggregate B (coarse aggregate)) in Example 6 is 315 N / mm ^{2, which is large.}
Further, the bending strength of the cementum hardened product (blending ratio of metal fibers: 3.1 to 4.0% by volume) in Examples 1 to 5 was 60 N / mm ² or more, and the cementum hardened product in Comparative Example 1 (mixed ratio: 3.1 to 4.0% by volume). ^{It can be seen that the bending strength (41 N / mm 2} ) of the metal fiber compounding ratio (2.0% by volume) is very large.
Further, it can be seen that the impact resistance (8 to 9 times) of the hardened cementum in Examples 1 to 6 is superior to the impact resistance (6 times) of the hardened cementum in Comparative Example 1.
Further, it can be seen that the cementum hardened products in Examples 1 to 6 are excellent in fire resistance.
From these results, it can be seen that the vault construction panel of the present invention has high compressive strength and bending strength, and is excellent in fire resistance and fracture resistance.
Further, it can be seen that the shrinkage strain of the hardened cementum in Examples 2 and 5 ^{is as small as 3 × 10-6} to 4 × ^10-6 , and the durability index is 100.
From these results, it can be seen that the vault construction panel of the present invention is excellent in dimensional stability and freeze-thaw resistance.

1 Laminated panel 2 Exterior material 3, 5, Panel for vault construction 4 Insulation material 6 Interior material 11 Flat plate specimen 12 Steel weight

Claims (6)

A panel for building a vault made of hardened cementum.
The hardened cement material is cement, silica fume with a BET specific surface area of 15 to 25 m ² / g, inorganic powder with a 50% cumulative particle size of 0.8 to 5 μm, and aggregate A with a maximum particle size of 1.2 mm or less. , A cured product of a cement composition containing a high-performance water reducing agent, defoaming agent, metal fiber, organic fiber and water.
The metal fiber is a metal fiber having a diameter of 0.01 to 1.0 mm, a length of 2 to 30 mm, and an aspect ratio (fiber length / fiber diameter) of 20 to 200.
The organic fiber is a polypropylene fiber having a diameter of 0.010 to 0.020 mm, a length of 4 to 8 mm, and an aspect ratio (fiber length / fiber diameter) of 300 to 470.
The ratio of the cement is 55 to 65% by volume, the ratio of the silica fume is 5 to 25% by volume, and the ratio of the inorganic powder is 15 to 35% by volume in the total amount of 100% by volume of the cement, the silica fume and the inorganic powder. The ratio of the metal fibers in the cement composition is 3.3 to 3.7% by volume, and the ratio of the organic fibers in the cement composition is 0.01 to 0.3% by volume. A panel for constructing a vault , which is characterized by being. The vault construction panel according to claim 1 , wherein the cement composition does not contain an aggregate having a maximum particle size of more than 1.2 mm and the compressive strength of the hardened cementum is 300 N / mm ² or more. .. The vault construction panel according to claim 1 , wherein the cement composition contains an aggregate B having a maximum particle size of more than 1.2 mm and 13 mm or less. The panel for constructing a vault according to claim 3 , wherein the hardened cementum has a compressive strength of 270 N / mm ² or more. The method for manufacturing the vault construction panel according to any one of claims 1 to 4.
A molding step of casting the above cement composition into a mold to obtain an uncured molded product, and
The uncured molded body is sealed or cured in the air at 10 to 40 ° C. for 24 hours or more, and then removed from the mold to obtain a cured molded body at room temperature.
The cured molded product is cured by steam curing or hot water curing at 70 ° C. or higher and lower than 100 ° C. for 6 hours or longer, or autoclave curing at 100 to 200 ° C. for 1 hour or longer, and then curing after heat curing. The heat curing process to get the body and
It is characterized by including a high temperature heating step of heating the cured product after heat curing at 150 to 200 ° C. for 24 hours or more (however, heating by autoclave curing is excluded) to obtain the panel for constructing the vault. How to manufacture a panel for building a vault. The method for manufacturing a panel for constructing a safe room according to claim 5 , further comprising a water absorption step of causing the cured molded body to absorb water between the normal temperature curing step and the heat curing step.

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