JP6489811B2 - Method for producing hardened cementitious body - Google Patents

Description

  The present invention relates to a method for producing a hardened cementitious body by imparting a desired shape using a mold formed using a three-dimensional modeling system (hereinafter referred to as “3D printer”).

  One method of imparting design properties to hardened cementitious materials such as mortar, concrete, and hardened cement paste is a method of forming using a decorative mold, and various decorative molds are known. For example, a synthetic resin foam decorative mold frame (Patent Document 1) that forms a concave and convex design including joints on the concrete surface, and a locking portion on the back side of the decorative mold frame design plate member having a concave and convex design on the front surface A decorative mold frame (Patent Document 2) in which the decorative mold frame design plate member is locked to the decorative mold frame body by the locking portion, and a synthetic elastic polymer material on the bottom surface of the cement molding hardening mold Design transfer material (Patent Document 3) having a desired surface concavo-convex pattern, concrete casting decorative frame (Patent Document 4) having a concavo-convex pattern on the surface in contact with concrete and attached to the mold panel on the back surface It has been known.

  However, as can be seen from the descriptions in these documents, the shape that can be imparted is limited to a monotonous design such as a concavo-convex pattern, and it has been difficult to impart a delicate and diverse design to the hardened cementitious material.

JP 2001-277227 A Japanese Patent Laid-Open No. 10-266558 Japanese Patent Application Laid-Open No. 08-011110 Japanese Patent Application Laid-Open No. 07-279424

  Then, an object of this invention is to provide the manufacturing method of the cementitious hardened | cured material which can provide a delicate and various design to a cementitious hardened | cured material.

  As a result of intensive studies to solve the above problems, the present inventor can produce a mold having precise and various shapes and patterns by using a 3D printer, and the cementitious material produced by using the mold. The cured body was found to have precise and various shapes and patterns, and the present invention was completed.

That is, this invention is a manufacturing method of the cementitious hardening body which has the following structures.
[1] Using an acrylic resin mold having a glass transition point of 80 to 120 ° C. produced using a three-dimensional modeling system, a cemented cured body is molded and heated to 80 to 120 ° C. A method for producing a cementitious hardened body produced by demolding,
The method for producing a cementitious hardened body, wherein the hardened cementitious body is a hardened body of a composition satisfying all the following conditions (A) to (G): (Does not include components.)
(A) cement and
For 100 parts by mass of the cement,
(B) 80-180 parts by mass of fine aggregate having a maximum particle size of 1.0 mm or less,
(C) 10 to 40 parts by mass of silica fume having a BET specific surface area of 10 to 25 m ² / g (D) 30 to 40 parts by mass of quartz powder having a Blane specific surface area of 6,500 to 8,500 cm ² / g (E) Quartz powder having a specific surface area of 3,500 to 4,200 cm ² / g is 1.5 parts by mass or more and less than 5 parts by mass (F) 0.3 to 1.5 parts by mass of polycarboxylic acid-based high-performance water reducing agent. And (G) a cured product of a blend containing 15 to 25 parts by mass of water.

  According to the method for producing a hardened cementitious material of the present invention, a delicate and diverse design can be imparted to the hardened cementitious material, and demolding is easy.

It is a photograph which shows an example of the resin-made formwork used by this invention. It is a photograph which shows the state immediately after pouring a cement compound (a thing before a cementitious hardened body hardens | cures) into a resin-made formwork. It is a photograph which shows the state which the cement compound hardened | cured within the resin-made formwork. (A), (B) is a photograph which shows a mode that a cementitious hardened | cured material is demolded from a resin-made formwork. It is a photograph which shows a cementitious hardened body and a resin-made formwork.

  As described above, the method for producing a hardened cementitious material of the present invention is a method for producing a hardened cementitious material by using a resin mold formed using a 3D printer. Hereinafter, the present invention will be described in detail for a 3D printer, a resin mold, and a hardened cementitious material.

1.3D Printer A 3D printer (three-dimensional modeling system) is a type of industrial robot that uses a 3D data created on a computer as a design drawing to create a three-dimensional object by stacking cross-sectional shapes. The present invention is characterized in that a cementitious hardened body is produced using a resin mold having an arbitrary shape and pattern produced using this 3D printer.
Commercially available products can be used for the 3D printer used in the present invention, and the modeling method may be any one of a hot melt lamination method, an optical modeling method, a powder fixing method, a powder sintering method, an inkjet method, and a cutting method.

2. Resin mold (1) Thermoplastic resin The thermoplastic resin forming the resin mold used in the present invention includes (i) a monofunctional ethylenically unsaturated monomer and (ii) a polyfunctional ethylene containing no urethane group. And (iii) a copolymer obtained by polymerizing (iii) a urethane group-containing ethylenically unsaturated monomer using a photopolymerization initiator. The glass transition point of the thermoplastic resin is preferably 50 to 120 ° C., more preferably 80 to 120 ° C., from the viewpoint of easy demolding and heat resistance.

(I) Monofunctional ethylenically unsaturated monomer The monofunctional ethylenically unsaturated monomer includes methyl (meth) acrylate, ethyl (meth) acrylate, isobutyl (meth) acrylate, lauryl (meth) acrylate, stearyl ( (Meth) acrylate, isostearyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-t-cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, Tetrahydrofurfuryl (meth) acrylate, 4- (meth) acryloyloxymethyl-2-methyl-2-ethyl-1,3-dioxolane, 4- (meth) acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane, Adamantyl (me ) Acrylate. Hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol, mono (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, polypropylene glycol, mono (meth) acrylate, Methoxy polypropylene glycol mono (meth) acrylate, (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-butyl (meth) acrylamide, N, N ′ -Dimethyl (meth) acrylamide, N, N'-diethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-hydroxypropyl (meth) acrylami , One or more selected from the group consisting of N- hydroxybutyl (meth) acrylamide, and acryloyl morpholine and the like.

(Ii) Polyfunctional ethylenically unsaturated monomer having no urethane group The polyfunctional ethylenically unsaturated monomer having no urethane group is a compound having two or more ethylenically unsaturated groups having no urethane group. The mechanical strength and elastic modulus are increased by crosslinking the polymer with the compound. The polyfunctional ethylenically unsaturated monomer having no urethane group is 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, or 1,9-nonanediol di (meth) acrylate. From 3-methyl-1,5-pentanediol di (meth) acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate 1 type or more chosen from the group which consists of.

(Iii) Urethane group-containing ethylenically unsaturated monomer The urethane group-containing ethylenically unsaturated monomer has a function of adjusting the toughness and elongation of the polymer and has a hydroxyl group and a (meth) acryloyl group. And those containing polyisocyanates.
The compound having a hydroxyl group and a (meth) acryloyl group is polycarbonate diol, PEG, or polyester diol mono (meth) acrylate, (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxy. Propyl, (meth) acrylic acid-2-hydroxybutyl, and an alkylene oxide or ε-caprolactam added thereto, (meth) acrylic acid-2-hydroxyethyl-ε-caprolactone 2 mol adduct, 3-phenoxy 2-hydroxypropyl (meth) acrylate, 3-biphenoxy-2-hydroxyprop (meth) acrylate, glycerol mono- and di (meth) acrylate, trimethylolpropane mono- and di (meth) acrylate, pentaerythris Ritol mono-, di- and tri (meth) acrylate, ditrimethylolpropane mono-, di- and tri (meth) acrylate, dipentaerythritol mono-, di-, tri-, tetra- and penta (meth) acrylate, and these And one or more selected from the group consisting of adducts of alkylene oxides.

  The polyisocyanate may be 2,4- and / or 2,6-tolylene diisocyanate (TDI), 4,4′- and / or 2,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2, 4- and / or 2,6-methylcyclohexane diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, m- and / or p-xylylene diisocyanate, and α, α, α ′, α′-tetramethylxylylene diisocyanate 1 type or more chosen from the group which consists of.

(Iv) Photopolymerization initiator The photopolymerization initiator includes benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy. 2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio ) Phenyl] -2-morpholinopropan-1-one, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, 2-amylanthraquinone, 2,4-diethylthioxanthone, 2-isopropyl Thioxanthone, 2-chlorothioxanthone, acetophenone dimethyl ketal, benzyl dimethyl ketal, benzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, 4,4′-bismethylaminobenzophenone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, Bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and 1- [4- (2-hydroxyethoxy) 1 or more types selected from the group consisting of phenyl] -2-methyl-1-propan-1-one.

  In the monofunctional ethylenically unsaturated monomer, the content of the thermoplastic resin and the photopolymerization initiator used in the present invention is preferably 50 to 90 from the viewpoint of improving the glass transition point and brittleness resistance of the thermoplastic resin. In the polyfunctional ethylenically unsaturated monomer not containing the urethane group, preferably 3 to 25% by mass of the urethane group-containing ethylenically unsaturated monomer from the viewpoint of mechanical strength and brittle resistance of the thermoplastic resin. From the viewpoint of the toughness and hardness of the thermoplastic resin, the amount is preferably 5 to 35% by mass, and from the viewpoint of the photocuring rate, the photopolymerization initiator is preferably 0.1 to 10% by mass.

(2) Water-soluble resin The water-soluble resin forming the resin mold used in the present invention includes (i) a water-soluble monofunctional ethylenically unsaturated monomer and / or (ii) an alkylene oxide containing an oxypropylene group. A homopolymer or copolymer obtained by polymerizing an adduct using (iii) a photopolymerization initiator. The water-soluble resin is preferably one that completely dissolves within 24 hours from the time when 1 g of the water-soluble resin is placed in 100 ml of water at 20 ° C.

(I) Water-soluble monofunctional ethylenically unsaturated monomer The water-soluble monofunctional ethylenically unsaturated monomer is hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate. , Polyethylene glycol mono (meth) acrylate, monoalkoxy polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, monoalkoxy polypropylene glycol mono (meth) acrylate, mono (meth) acrylate of PEG-PPG block polymer, ( (Meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-butyl (meth) acrylamide, N, N′-dimethyl (meth) 1 or more types chosen from the group which consists of acrylamide, N, N'-diethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-hydroxypropyl (meth) acrylamide, and N-hydroxybutyl (meth) acrylamide are mentioned. It is done.

(Ii) Alkylene oxide adduct containing an oxypropylene group The alkylene oxide adduct containing an oxypropylene group includes at least propylene oxide alone or propylene oxide in an active hydrogen compound such as a 1-4 tetrahydric alcohol and an amine compound. It is a compound to which other alkylene oxide is added.

(Iii) Photopolymerization initiator The photopolymerization initiator used here is the same as the photopolymerization initiator used for the thermoplastic resin.

  Further, the content of the water-soluble resin and the photopolymerization initiator used in the present invention is preferably 3 to 45% by mass in the water-soluble monofunctional ethylenically unsaturated monomer from the viewpoint of solubility in water. From the viewpoint of solubility in water, the alkylene oxide adduct containing the oxypropylene group is preferably 50 to 95% by mass, and the photopolymerization initiator is 0.1 to 10% by mass.

(3) Resin mold The shape of the resin mold is not particularly limited, and is arbitrary such as a manhole mold, an uneven mold, a curved mold, a wall mold, and a column mold The form of the product of the shape is produced using a 3D printer.

3. Next, the cementitious cured body according to the present invention will be described.
The cementitious hardened body is cement, a pozzolanic fine powder having a BET specific surface area of 10 to 25 m ² / g, a fine aggregate having a maximum particle size of 3.5 mm or less, and a brane specific surface area of 3,500 to 10,000 cm ² / The hardened | cured material of the mixture containing g inorganic powder, a water reducing agent, and water is preferable, and also the hardened | cured material of the formulation containing an antifoamer and / or a reinforcing fiber is more preferable.

(1) Cement The cement used in the present invention is not particularly limited, and is one selected from the group consisting of ordinary Portland cement, early-strength Portland cement, moderately hot Portland cement, low heat Portland cement, blast furnace cement, and fly ash cement. The above is mentioned. In the present invention, early strength Portland cement is preferable when improvement in early strength development is required, and medium heat Portland cement or low heat Portland cement is preferable when fluidity improvement of the cement composition is required. Is more preferred.

(2) Pozzolanic fine powder The BET specific surface area of the pozzolanic fine powder used in the present invention is 10 to 25 m ² / g. When the BET specific surface area is less than 10 m ² / g, the strength expression of the cured product is lowered. When the BET specific surface area exceeds 25 m ² / g, the fluidity of the blend decreases. Moreover, it is difficult to obtain a pozzolanic fine powder having a BET specific surface area exceeding 25 m ² / g. A preferable BET specific surface area of the pozzolanic fine powder is 15 to 20 m ² / g from the fluidity of the blend and the strength development of the cured product.
Examples of the pozzolanic fine powder include one or more selected from the group consisting of silica fume, silica dust, fly ash, slag, volcanic ash, silica sol, and precipitated silica. Among these, silica fume and silica dust have a BET specific surface area of 10 to 25 m ² / g and are advantageous in terms of cost because it is not necessary to perform pulverization or the like.

  The blending amount of the pozzolanic fine powder is preferably 5 to 50 parts by weight and more preferably 10 to 40 parts by weight with respect to 100 parts by weight of cement from the viewpoint of fluidity of the blend and strength development of the cured body. When the blending amount is less than 5 parts by mass, the fluidity of the blend, the strength development of the cured product, and the durability are deteriorated, and after use of the cured product, chipping or peeling of the cured product occurs. There is a risk. Moreover, when this compounding quantity exceeds 50 mass parts, the fluidity | liquidity of a compound will fall and operations, such as shaping | molding, will become difficult.

(3) Fine aggregate The maximum particle size of the fine aggregate used in the present invention is 3.5 mm or less. When the maximum particle size of the fine aggregate exceeds 3.5 mm, the strength development property of the cured body is lowered. In addition, it is preferable to use a fine aggregate having a maximum particle size of 2.0 mm or less, and more preferably a fine aggregate having a maximum particle size of 1.0 mm or less, from the viewpoint of strength development of the cured body. Fine aggregates include river sand, land sand, sea sand, crushed sand, quartz sand, and mixtures thereof.
The amount of fine aggregate blended is preferably based on 100 parts by weight of cement from the viewpoints of fluidity of the blend, strength development of the cured body, reduction of self-shrinkage and drying shrinkage, and reduction of calorific value of hydration. Is 50 to 250 parts by mass, more preferably 80 to 180 parts by mass.

(4) Inorganic powder The brane specific surface area of the inorganic powder used in the present invention is 3,500 to 10,000 cm ² / g. When the Blaine specific surface area is outside this range, the fluidity of the blend and the strength development of the cured product are reduced.
Examples of the inorganic powder include quartz powder, limestone powder, slag powder, fly ash, feldspar powder, mullite powder, alumina powder, volcanic ash, silica sol powder, carbide powder, and nitride powder.
The blending amount of the inorganic powder is preferably 15 to 50 parts by mass with respect to 100 parts by mass of cement from the viewpoint of fluidity of the blend and strength development of the cured body.

In the present invention, the inorganic powder, the inorganic particles A of Blaine specific surface area of 5,000~10,000cm ² / g, the Blaine specific surface area of 3,500~5,000cm ² / g inorganic particles B (provided that The inorganic particles B preferably have a smaller specific surface area than the inorganic particles A). By using two kinds of inorganic powders having different particle sizes in this way, fluidity and strength development are further improved.
As the inorganic particles A and B constituting the inorganic powder, the same kind of powder (for example, quartz powder) may be used, or different kinds of powder (for example, quartz powder and limestone powder) may be used. However, in the present invention, it is preferable to use the same kind of powder as the inorganic particles A and B.

The Blaine specific surface area of the inorganic particles A is 5,000 to 10,000 cm ² / g, preferably 5,500 to 9,500 cm ² / g, more preferably 6,000 to 9,000 cm ² / g, particularly preferably. It is 6,500-8,500 cm < ² > / g. When the value is less than 5,000 cm ² / g, the difference between the cement and the inorganic particles B and the Blaine specific surface area becomes small, and the effect of improving fluidity and strength development is reduced. When the value exceeds 10,000 cm ² / g, there is a problem that it takes time and labor to pulverize to obtain inorganic particles A having such a small particle size.

The Blaine specific surface area of the inorganic particles B is 3,500 to 5,000 cm ² / g, preferably 3,500 to 4,800 cm ² / g, more preferably 3,500 to 4,500 cm ² / g, particularly preferably. It is 3,500-4,200 cm < ² > / g. When the value is less than 3,500 cm ² / g, the fluidity of the blend may be lowered. When the value exceeds 5,000 cm ² / g, the difference from the Blaine specific surface area of the inorganic particles A becomes small, and the effect of improving fluidity and strength development is reduced.

The difference in the Blaine specific surface area between the inorganic particles A and the inorganic particles B is preferably 2,000 cm ² / g or more, more preferably 2,500 cm ² / g or more, still more preferably 3,000 cm ² / g or more, particularly preferably. It is 3,500 cm ² / g or more. When the difference is 2,000 cm ² / g or more, fluidity and strength development are further improved.

The difference in the Blaine specific surface area between the cement and the inorganic particles B is preferably 200 cm ² / g or more, more preferably 250 cm ² / g or more, still more preferably 350 cm ² / g or more, and particularly preferably 450 cm ² / g or more. When the difference is 200 cm ² / g or more, fluidity and strength development are further improved.

  When inorganic powder is comprised from the inorganic particle A and the inorganic particle B, the compounding quantity of the inorganic particle A is 14-54 mass parts with respect to 100 mass parts of cement, Preferably it is 20-50 mass parts, More preferably It is 25-45 mass parts, More preferably, it is 30-40 mass parts. When the blending amount is out of the range of 14 to 54 parts by mass, the fluidity of the blend may be lowered.

  The compounding amount of the inorganic particles B is 1 to 15 parts by mass, preferably 1.5 to 10 parts by mass, more preferably 1.5 to 5 parts by mass, and still more preferably 1.5 parts by mass with respect to 100 parts by mass of cement. Part or more and less than 5 parts by mass. When the blending amount is outside the range of 1 to 15 parts by mass, the fluidity of the blend may be lowered.

(5) Water reducing agent The water reducing agent used in the present invention is a lignin-based, naphthalenesulfonic acid-based, melamine-based, or polycarboxylic acid-based water reducing agent, an AE water reducing agent, a high-performance water reducing agent, or a high-performance AE water reducing agent. is there. Among these, a polycarboxylic acid-based high-performance water reducing agent is preferable because of its large water reducing effect.
The blending amount of the water reducing agent is preferably 0.1 to 4.0 parts by mass, more preferably 0.3 to 1.5 parts by mass in terms of solid content with respect to 100 parts by mass of cement. When the blending amount is less than 0.1 parts by mass, kneading becomes difficult, and the fluidity of the blend decreases. When the blending amount exceeds 4.0 parts by mass, the strength development of the cured body decreases. The water reducing agent can be used in either liquid or powder form.

(6) Water The amount of water is preferably 10 to 30 parts by mass, more preferably 15 to 25 parts by mass with respect to 100 parts by mass of cement. When the amount is less than 10 parts by mass, kneading becomes difficult, and the fluidity of the blend becomes low. When the amount exceeds 30 parts by mass, the strength development of the cured product decreases.

(7) Antifoaming agent In this invention, it is preferable that a hardening body contains an antifoaming agent further. When the antifoaming agent is blended, fluidity and strength development are improved, and the amount of surface bubbles of the cured product after curing is reduced, so that the aesthetics of the cured product is improved.
The blending amount of the antifoaming agent is preferably 100 g or less, more preferably 5 to 70 g, as the amount of the defoaming agent component (component other than water in the commercially available defoaming agent) in the composition 1 m ³ . Especially preferably, it is 7-30g.

(8) Reinforcing fiber In the present invention, the cured body preferably further contains a reinforcing fiber. When the reinforcing fiber is blended, the bending strength and fracture energy of the cured body are improved. Examples of the reinforcing fibers include metal fibers, organic fibers, and carbon fibers.
Metal fibers include steel fibers and amorphous fibers. Among these, steel fibers are suitable because they have high strength and are excellent in terms of cost and availability. The shape and dimensions of the metal fibers are preferably a length of 2 mm or more and a length / diameter ratio of 20 or more, more preferably a length of 2 to 30 mm and a length / diameter ratio of 20 ~ 200.
If the length of the metal fiber is less than 2 mm, the effect of improving the bending strength is lowered, and if it exceeds 30 mm, fiber balls are likely to be produced during kneading. Moreover, when the ratio of length / diameter of the metal fiber is less than 20, the number of the same compounding amount (same volume) decreases, and the effect of improving the bending strength is lowered. It becomes easy to cut when it receives strength due to insufficient strength.
If the compounding quantity of a metal fiber is shown by the ratio of the volume in a compounding composition, it is preferably 4 volume% or less, More preferably, it is 0.5-3.5 volume%. If it exceeds 4% by volume, the unit water amount increases in order to ensure workability during kneading, and the strength of the cured product may be reduced.

Examples of the organic fiber include one or more selected from the group consisting of vinylon fiber, polypropylene fiber, polyethylene fiber, aramid fiber, and carbon fiber. Among these, vinylon fiber and polypropylene fiber are preferable because they have high strength and are low in cost and excellent in availability.
The shape and dimensions of the organic fibers are preferably 2 mm or more in length and a length / diameter ratio of 20 or more, more preferably 2 to 30 mm in length and 20 in length / diameter. ~ 500. If the length of the organic fiber is less than 2 mm, the effect of improving the breaking strength is reduced, and if it exceeds 30 mm, fiber balls are likely to be produced during kneading.
If the length / diameter ratio of the organic fiber is less than 20, the number of organic fibers at the same blending amount (same volume) decreases, and the effect of improving the breaking strength decreases. If the ratio exceeds 500, the organic fiber itself The strength of the is insufficient, and it becomes easy to break when subjected to tension.
The compounding amount of the organic fiber is preferably 10% by volume or less, and more preferably 0.5 to 8.0% by volume, as a volume ratio in the formulation. If it exceeds 10%, the unit water amount must be increased in order to ensure workability during kneading, and the strength of the cured product may be reduced.

Examples of the carbon fiber include PAN-based carbon fiber and pitch-based carbon fiber. Moreover, the dimension, aspect ratio, and compounding quantity of carbon fiber are the same as that of organic fiber.
In the present invention, metal fibers and organic fibers may be used in combination. In this case, the blending amount (total amount) of the metal fiber and the organic fiber is a volume ratio in the blend, preferably 0.1 to 10% by volume, more preferably 0.5 to 8.0% by volume. .

The kneading method of the blend is not particularly limited, for example,
(A) A method of mixing materials other than water and a water reducing agent in advance to prepare a premix material, and adding the premix material, water and the water reducing agent to a mixer and kneading them,
(B) A method of mixing materials other than water (however, a water reducing agent is in powder form) to prepare a premix material, and charging the premix material and water into a mixer and kneading,
(C) A method in which each material is individually put into a mixer and kneaded is exemplified.

  As the mixer used for kneading, any type of mixer used for ordinary concrete kneading can be used, and examples thereof include an oscillating mixer, a pan type mixer, and a biaxial kneading mixer. After kneading, the compound is put into a predetermined mold and molded, and then cured to produce a cementitious hardened body. Curing methods include air curing and steam curing.

(9) Demolding method In the present invention, when the resin forming the resin mold is a thermoplastic resin, the demolding method is performed by heating the mold including the hardened cementitious body. And heating temperature becomes like this. Preferably it is 80 degreeC or more from the ease of demolding.
When the resin is a water-soluble resin, the mold containing the cementitious hardened body is dissolved in water and demolded, or swollen and demolded. As a specific method, a mold containing a cementitious hardened body is immersed in water to dissolve the mold or swell, or water is continuously applied to the mold to dissolve the mold. Or a method of swelling. In addition, the immersion time in the case of being immersed in water becomes like this. Preferably it is 24 hours or less, More preferably, it is 12 hours or less.
In the case where the resin is composed of a thermoplastic resin and a water-soluble resin, the above-described heating and demolding may be performed as appropriate, or the mold may be demolded by dissolving in water or swelling. For example, in the case of a mold made of a thermoplastic resin on the outside and a water-soluble resin on the inside (side in contact with the hardened cementitious material), the inner water-soluble resin is dissolved in water or swelled to remove the mold. Can do.

The composition of the present invention has a flow value of 230 mm or more measured in the method described in “JIS R 5201 (Cement physical test method) 11. Flow test” without performing 15 drop motions. Excellent in properties. Therefore, the kneading operation of the blend, the operation of putting it in a resin mold and molding it are easy.
In addition, since the composition reaches every corner of the mold, a cured body having an arbitrary and precise shape can be produced with high accuracy.
Further, the cured product of the formulation of the present invention, a 130N / mm ² or more compression strength, after expressing 20 N / mm ² or more bending strength, since structurally are very densely formed, the mechanical strength And durability is less likely to occur. Moreover, since it is hard to generate | occur | produce a chip | tip and peeling in a hardening body, a fall of aesthetics is hard to produce.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this Example.
1. Materials used (1) Cement; Medium heat Portland cement (manufactured by Taiheiyo Cement)
(2) Pozzolanic fine powder; silica fume (BET specific surface area: 17 m ² / g)
(3) Fine aggregate: quartz sand No. 5 (maximum particle size: 0.6 mm)
(4) Quartz powder A (Blaine specific surface area: 7,500 cm ² / g)
(5) Quartz powder B (Blaine specific surface area: 3,800 cm ² / g)
(6) Water-reducing agent; Polycarboxylic acid-based high-performance water-reducing agent (7) Antifoaming agent; Polyether-based antifoaming agent (8) Water; Tap water

2. Manufacture of hardened cementitious material 30 parts by mass of silica fume, quartz powders A and B (total amount: 35 parts by mass, blending amount of quartz powder B in the total amount: 4.0 parts by mass with respect to 100 parts by mass of moderately heated Portland cement Part), 120 parts by weight of fine aggregate, 0.4 parts by weight of high-performance water reducing agent (in terms of solid content), 22 parts by weight of water, defoaming agent (15 g / amount of compound 1 m ³ (as components other than water) Conversion value)) was kneaded to prepare a blend.
The kneading of the blend was performed by the following method using a Hobart mixer.
Put medium hot heat Portland cement, silica fume, quartz powder A, quartz powder B, and fine aggregate into Hobart mixer, knead for 15 seconds, and then add water, high-performance water reducing agent, and antifoaming agent, Kneaded at low speed for 7 minutes. JIS R 5201 (Cement physical test method) 11. In the method described in the “flow test”, the flow value of the blend measured by omitting 15 dropping motions was 290 mm, and the fluidity was excellent.
Next, the mixture was poured into a thermoplastic resin (acrylic resin) mold shown in FIG. 1 (FIG. 2), pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. (FIG. 3), the mold was removed immediately after the completion of the steam curing (FIG. 4) to obtain a hardened cementitious body in the shape of a bottle shown in FIG. From FIG. 6, it can be seen that the shape of the screw portion of the bottle cap is formed cleanly.

Claims (1)

Using an acrylic resin mold with a glass transition point of 80 to 120 ° C. produced using a three-dimensional modeling system, a cemented hardened body is molded and heated to 80 to 120 ° C. for demolding. A method for producing a hardened cementitious body,
The method for producing a cementitious hardened body, wherein the hardened cementitious body is a hardened body of a composition satisfying all the following conditions (A) to (G): (Does not include components.)
(A) cement and
For 100 parts by mass of the cement,
(B) 80-180 parts by mass of fine aggregate having a maximum particle size of 1.0 mm or less,
(C) 10 to 40 parts by mass of silica fume with a BET specific surface area of 10 to 25 m ² / g (D) 30 to 40 parts by mass of quartz powder with a Blane specific surface area of 6,500 to 8,500 cm ² / g (E) Quartz powder having a specific surface area of 3,500 to 4,200 cm ² / g is 1.5 parts by mass or more and less than 5 parts by mass (F) 0.3 to 1.5 parts by mass of polycarboxylic acid-based high-performance water reducing agent. And (G) a cured product of a blend containing 15 to 25 parts by mass of water.