Telecentric forming with hydraulic components

Abstract

To provide a hydraulic composition for centrifugal molding with low viscosity of discharged sludge, and a method for producing a cured hydraulic composition.SOLUTION: A hydraulic composition for centrifugal molding comprises a following component (A), cement, aggregate, and water, with a ratio of water / cement of 15 mass% or more and 25 mass% or less, and with a content of the component (A) being 1.5 kg or more and 3.0 kg or less in the hydraulic composition for centrifugal molding 1 m3. The component (A) is: a copolymer comprising, as constituent monomers, at least one monomer (A1) selected from a fumaric acid, a (anhydrous) maleic acid, and salts thereof, a monomer (A2) represented by a general formula (A2), and a monomer (A3) represented by a general formula (A3). In the constituent monomers of the copolymer, a content of the monomer (A1) is 1 mass% or more and 30 mass% or less, a content of the monomer (A2) is 1 mass% or more and 20 mass% or less, and a content of the monomer (A3) is 50 mass% or more and 90 mass% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hydraulic composition for centrifugal molding and a method for producing a hardened product of the hydraulic composition. [Background technology]

[0002] Centrifugal molding is a known method for producing hollow cylindrical concrete products such as pipes, piles, poles, etc. In this method, mixed concrete material is poured into a formwork, which is then rotated at high speed to generate centrifugal force that presses the concrete against the inner surface of the formwork, thereby compacting it.

[0003] In hydraulic compositions for centrifugal molding, naphthalene-based dispersants are often used as dispersants from the viewpoint of moldability of centrifugal molded products, but there is a growing need for higher strength and earthquake resistance both domestically and internationally, and as disclosed in Non-Patent Document 1, in areas where a high-strength hardened body is required, that is, areas where the unit water content of concrete is low, mixing with naphthalene-based dispersants becomes difficult, making practical use difficult. For this reason, the use of polycarboxylic acid-based dispersants, which have high water-reducing properties, is increasing.

[0004] Patent Document 1 describes a hydraulic composition for centrifugal molding that contains (A) a dispersant for hydraulic powder made of a polymer compound containing an aromatic ring, (B) one or more compounds selected from the specific compounds represented by general formulas (B1) to (B4), hydraulic powder, aggregate, and water, and has a water / hydraulic powder ratio of more than 25% by mass and not more than 35% by mass.

[0005] Patent Document 2 describes a strength-enhancing additive for centrifugally molded concrete, which is characterized by containing (a) a copolymer consisting of 50 to 98 mass % of a monomer (A) represented by formula (1), 1 to 49 mass % of a monomer (B) represented by a specific formula, and 0.1 to 5 mass % of a monomer (C) represented by a specific formula, and (b) a copolymer of a polyoxyalkylene derivative and an unsaturated carboxylic acid compound, in a mass ratio of (a):(b)=50 to 80:20 to 50 {the total mass of (a) and (b) being 100}.

[0006] Patent Document 3 describes a concrete composition for centrifugation containing cement, a high-strength material, and a water-soluble copolymer as an admixture, in which the water-soluble copolymer is a water-soluble copolymer obtained by polymerizing a monomer mixture containing one or more vinyl monomers (a) consisting of a compound having a polyoxyalkylene chain to which an average of 2 to 100 moles of alkylene oxide having 2 to 3 carbon atoms has been added, and one or more vinyl monomers (b) consisting of a compound having a carboxyl group, a sulfonic acid group, or an amide group, or a water-soluble salt thereof. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2018-48068 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-235384 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-253750 [Non-patent literature]

[0008] [Non-Patent Document 1] Journal of Structural Engineering, Architectural Institute of Japan, Vol. 606, pp. 29-34, Architectural Institute of Japan, August 2006 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when a polycarboxylic acid-based dispersant is used in a hydraulic composition for centrifugal molding, a problem arises in that sludge, which is cement sludge discharged as a result of centrifugal molding, is generated. Sludge forms inside the unhardened centrifugal compact due to centrifugal force. Especially in areas with low water content, the volumetric concentration of cement in the sludge increases, resulting in high sludge viscosity. When the sludge is discharged, it gouges away the inner surface of the unhardened centrifugal compact, leaving ribs on the surface, reducing yield and exposing the gravel, resulting in poor product quality. However, by carefully controlling the quality of concrete materials and manufacturing conditions, it is possible to produce concrete without discharging the sludge. However, because sludge has a lower density and strength than the concrete compact, leaving it inside the concrete compact will not be able to withstand the shrinkage deformation during hardening, causing cracks in the sludge layer inside the pile, which can affect the aesthetic appearance of the compacted interior. Therefore, manufacturers often discharge and discard this sludge to eliminate the cracking sludge layer and improve the aesthetic appearance of the compacted interior. Therefore, the present inventors have found that there is a problem with the viscosity of the sludge discharged as a result of centrifugal compaction.

[0010] The present invention provides a hydraulic composition for centrifugal molding which produces a discharged sludge with low viscosity, and a method for producing a hardened product of the hydraulic composition. [Means for solving the problem]

[0011] The present invention provides a hydraulic composition for centrifugal molding containing the following component (A), cement, aggregate, and water, wherein the water / cement ratio is 15% by mass or more and 25% by mass or less, and the content of component (A) is 3 The present invention relates to a hydraulic composition for centrifugal molding, the weight of which is 1.5 kg or more and 3.0 kg or less. Component (A): A copolymer containing, as constituent monomers, one or more monomers (A1) selected from fumaric acid, maleic acid (anhydride), and salts thereof, a monomer (A2) represented by the following general formula (A2), and a monomer (A3) represented by the following general formula (A3), wherein, among the constituent monomers of the copolymer, the proportion of monomer (A1) is 1% by mass or more and 30% by mass or less, the proportion of monomer (A2) is 1% by mass or more and 20% by mass or less, and the proportion of monomer (A3) is 50% by mass or more and 90% by mass or less.

[0012] [ka]

[0013] [In general formula (A2), R 21a , R 22a , R 23a may be the same or different and are a hydrogen atom, a methyl group, or COOM; M is a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2 atom), an ammonium group, an alkylammonium group, or a substituted alkylammonium group; and Z is a group that bonds, via an amide bond, to a carbon atom in the main chain of a polyamidepolyamine obtained by condensing a dibasic acid with a polyalkylenepolyamine and / or a modified polyamidepolyamine obtained by adding 0.1 to 10 moles of an alkylene oxide having 2 to 4 carbon atoms per equivalent of the active imino group, amino group, or amide residue of the polyamidepolyamine.

[0014] [ka]

[0015] [In general formula (A3), R 31a , R 32a may be the same or different and are a hydrogen atom or a methyl group, and R 33a is a hydrogen atom or -COO(AO) n X, where X is an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, AO is a group selected from an ethyleneoxy group and a propyleneoxy group, n is the average number of moles of AO added and is a number of 5 to 150, p is a number of 0 to 2, and q is a number of 0 or 1.

[0016] The present invention also relates to a method for producing a hardened hydraulic composition, which comprises the following steps: Step 1: Mixing the component (A), cement, aggregate, and water in a ratio of water / cement of 15% by mass or more and 25% by mass or less, and mixing the component (A) in an amount of 1 / m of the hydraulic composition. 3A process of mixing 1.5 kg to 3.0 kg of the mixture to obtain a hydraulic composition, and filling the obtained hydraulic composition into a formwork. Step 2: A step of clamping the hydraulic composition filled in the form obtained in step 1 by applying centrifugal force. Step 3: A step of allowing the clamped hydraulic composition obtained in step 2 to set in the formwork. [Effects of the Invention]

[0017] According to the present invention, there are provided a hydraulic composition for centrifugal molding which produces a discharged sludge with low viscosity, and a method for producing a hardened product of the hydraulic composition.

[0018] In recent years, the Sustainable Development Goals (SDGs) have been advocated to realize a sustainable society. This invention can improve yield and simplify the sludge discharge process, and is thought to be a technology that can contribute to SDGs 7, 8, 9, 11, 12, and 14, for example. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present inventors have found that the sludge discharged as a result of centrifugal molding of the hydraulic composition for centrifugal molding of the present invention has a low viscosity. The reason for this effect is not entirely clear, but is presumed to be as follows. During the production of compacts from centrifugally moldable hydraulic compositions, the low-density cement sludge in the hydraulic composition collects at the center of the compact due to centrifugal force, forming sludge. It is believed that cement sludge is primarily composed of relatively low-density components, particularly calcium silicate, among the hydration products produced by the hydration reaction of cement. In the centrifugally moldable hydraulic composition of the present invention, the copolymer of component (A) contains an amino group in the constituent monomer of component (A), and therefore component (A) is believed to adsorb to calcium silicate in the cement sludge via the amino group of monomer (A2). Additionally, the repulsive force provided by monomer (A3) contained in the constituent monomer of component (A) is believed to effectively disperse the adsorbed calcium silicate and solids in the sludge, thereby reducing the viscosity of the sludge.

[0020] [Hydraulic composition for centrifugal molding] The present invention relates to a hydraulic composition for centrifugal molding containing component (A), cement, aggregate, and water, wherein the water / cement ratio is 15% by mass or more and 25% by mass or less, and the content of component (A) is 3 The present invention relates to a hydraulic composition for centrifugal molding, the weight of which is 1.5 kg or more and 3.0 kg or less.

[0021] <Component (A)> Component (A) is a copolymer containing, as constituent monomers, one or more monomers (A1) selected from fumaric acid, maleic acid (anhydride), and salts thereof, a monomer (A2) represented by the following general formula (A2), and a monomer (A3) represented by the following general formula (A3), wherein, among the constituent monomers of the copolymer, the proportion of monomer (A1) is from 1% to 30% by mass, the proportion of monomer (A2) is from 1% to 20% by mass, and the proportion of monomer (A3) is from 50% to 90% by mass.

[0022] [ka]

[0023] [In general formula (A2), R21a , R 22a , R 23a may be the same or different and are a hydrogen atom, a methyl group, or COOM; M is a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2 atom), an ammonium group, an alkylammonium group, or a substituted alkylammonium group; and Z is a group that bonds, via an amide bond, to a carbon atom in the main chain of a polyamidepolyamine obtained by condensing a dibasic acid with a polyalkylenepolyamine and / or a modified polyamidepolyamine obtained by adding 0.1 to 10 moles of an alkylene oxide having 2 to 4 carbon atoms per equivalent of the active imino group, amino group, or amide residue of the polyamidepolyamine.

[0024] [ka]

[0025] [In general formula (A3), R 31a , R 32a may be the same or different and are a hydrogen atom or a methyl group, and R 33a is a hydrogen atom or -COO(AO) n X, where X is an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, AO is a group selected from an ethyleneoxy group and a propyleneoxy group, n is the average number of moles of AO added and is a number of 5 to 150, p is a number of 0 to 2, and q is a number of 0 or 1.

[0026] Monomer (A1) is one or more monomers selected from fumaric acid, maleic acid (anhydride), and salts thereof, and from the viewpoint of copolymerizability, fumaric acid or a salt thereof is preferred. Examples of the salt include alkali metal salts, alkaline earth metal salts, ammonium salts, alkylammonium salts, and substituted alkylammonium salts. Maleic acid (anhydride) refers to maleic acid and / or maleic acid anhydride.

[0027] In the monomer (A2), in the general formula (A2), R 21aFrom the viewpoint of reactivity, is preferably a hydrogen atom or COOM, more preferably COOM. In general formula (A2), R 22a From the viewpoint of copolymerizability, is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom. In general formula (A2), R 23a From the viewpoint of copolymerizability, is preferably a hydrogen atom or COOM, more preferably COOM.

[0028] In general formula (A2), the dibasic acid constituting Z is an aliphatic saturated dibasic acid having 2 or more, preferably 4 or more, and 10 or less, preferably 8 or less, carbon atoms, from the viewpoint of copolymerizability. Examples of dibasic acids include one or more selected from oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. From the viewpoint of copolymerizability, one or more selected from adipic acid, glutaric acid, and succinic acid are preferred. The polyalkylene polyamine constituting Z may be one or more selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, and a mixture of high molecular weight polyethylene polyamines that are mixtures containing many ethylene units and nitrogen atoms. From the viewpoint of copolymerizability, the polyalkylene polyamine is preferably one or more selected from diethylenetriamine, triethylenetetramine, and a mixture of high molecular weight polyethylene polyamines that are mixtures containing many ethylene units and nitrogen atoms.

[0029] Monomer (A2) is a monomer obtained by bonding, via an amide bond, a polyamidepolyamine, which is a condensation product of such a dibasic acid and a polyalkylenepolyamine, and / or a modified polyamidepolyamine in which, from the viewpoint of copolymerizability, an alkylene oxide having from 2 to 4 carbon atoms, preferably ethylene oxide, is added in an amount of 0.1 mole or more, preferably 1 mole or more and 10 moles or less, preferably 5 moles or less, per equivalent of the active imino group, amino group, or amide residue of the polyamidepolyamine, to one or more members selected from maleic anhydride, maleic acid, fumaric acid, acrylic acid, methacrylic acid, and salts thereof.

[0030] In the monomer (A3), in the general formula (A3), R 31a is preferably a hydrogen atom from the viewpoint of copolymerizability. In general formula (A3), R 32a From the viewpoint of copolymerizability, a methyl group is preferred. In general formula (A3), R 33a is preferably a hydrogen atom from the viewpoint of copolymerizability. In general formula (A3), X is preferably a methyl group or a hydrogen atom from the viewpoint of copolymerizability. In general formula (A3), from the viewpoint of cement dispersibility, AO is preferably an alkyleneoxy group having a carbon number of 2 or more and 3 or less. AO preferably contains an ethyleneoxy group.

[0031] In general formula (A3), n is the average number of moles of AO added, and is a number of 5 to 150. From the viewpoint of cement dispersibility, n is preferably 10 or more, more preferably 20 or more, even more preferably 30 or more, and still more preferably 40 or more, and from the viewpoint of workability, n is preferably a number of 120 or less, more preferably 90 or less, and even more preferably 60 or less.

[0032] In the general formula (A3), p is preferably 1 or 2 from the viewpoint of copolymerizability. In the general formula (A3), q is preferably 0 from the viewpoint of copolymerizability.

[0033] The copolymer of component (A) may contain a monomer other than monomer (A1), monomer (A2), and monomer (A3) (hereinafter also referred to as monomer (A4)) as a constituent monomer. Examples of monomer (A4) include (meth)acrylic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, 2-(methacryloyloxy)ethyl phosphate (HEMA-P), allyl sulfonic acid, methallylsulfonic acid, and salts thereof, such as alkali metal salts, alkaline earth metal salts, ammonium salts, and amine salts. Further examples include structural units using monomers such as (meth)acrylamide, N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, 2-(meth)acrylamido-2-methasulfonic acid, 2-(meth)acrylamido-2-ethanesulfonic acid, 2-(meth)acrylamido-2-propanesulfonic acid, styrene, and styrenesulfonic acid. (Meth)acrylic means acrylic or methacrylic.

[0034] From the viewpoint of cement dispersibility, the proportion of the monomer (A1) among the constituent monomers of the copolymer of component (A) is 1 mass% or more, preferably 5 mass% or more, more preferably 8 mass% or more, even more preferably 10 mass% or more, and 30 mass% or less, preferably 25 mass% or less, more preferably 20 mass% or less. The proportion of the monomer (A2) among the constituent monomers of the copolymer of component (A) is 1 mass% or more, preferably 1.5 mass% or more, more preferably 2.0 mass% or more, from the viewpoint of sludge suppression, and 20 mass% or less, preferably 15 mass% or less, more preferably 10 mass% or less, and even more preferably 5 mass% or less, from the viewpoint of cement dispersibility. From the viewpoint of cement dispersibility, the proportion of the monomer (A3) among the constituent monomers of the copolymer of component (A) is 50 mass% or more, preferably 60 mass% or more, more preferably 70 mass% or more, even more preferably 75 mass% or more, and is 90 mass% or less, preferably 87 mass% or less, more preferably 84 mass% or less.

[0035] In the copolymer of component (A), the total proportion of the monomer (A1), the monomer (A2), and the monomer (A3) in all constituent monomers is, from the viewpoint of suppressing sludge, preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and preferably 100% by mass or less, and may be 100% by mass.

[0036] From the viewpoint of cement dispersibility, the weight average molecular weight of the copolymer (A) is preferably 10,000 or more, more preferably 15,000 or more, even more preferably 20,000 or more, and preferably 70,000 or less, more preferably 60,000 or less, even more preferably 50,000 or less, still more preferably 40,000 or less, and still more preferably 30,000 or less. This weight average molecular weight is measured by gel permeation chromatography (GPC) under the following conditions. *GPC conditions Apparatus: GPC (HLC-8320GPC) manufactured by Tosoh Corporation Column: G4000PWXL + G2500PWXL (Tosoh Corporation) Eluent: 0.2M phosphate buffer / CH3CN=9 / 1 Flow rate: 1.0mL / min Column temperature: 40℃ Detection: RI Sample size: 0.2 mg / mL Standard substance: Polyethylene glycol equivalent (monodisperse polyethylene glycol: molecular weight 87,500, 250,000, 145,000, 46,000, 24,000)

[0037] <Cement> The hydraulic composition for centrifugal molding of the present invention contains cement. Examples of cement include ordinary Portland cement, belite cement, moderate-heat cement, high-early-strength cement, ultra-high-early-strength cement, sulfate-resistant cement, alumina cement, and CSA cement. Preferred are ordinary Portland cement, moderate-heat cement, high-early-strength cement, and ultra-high-early-strength cement. These cements may also contain blast furnace slag cement, fly ash cement, silica fume cement, or other high-strength admixtures, such as blast furnace slag cement, fly ash cement, or silica fume cement, to which powders having posolan properties and / or latent hydraulic properties, or stone powder (calcium carbonate powder), have been added.

[0038] <High strength admixture> The hydraulic composition for centrifugal molding of the present invention may contain a high-strength admixture. Examples of high-strength admixtures include powders with pozzolanic action and / or latent hydraulic properties, such as blast furnace slag, fly ash, anhydrous gypsum, and silica fume, as well as stone powder (calcium carbonate powder). Here, when the cement or high-strength admixture contains a powder selected from a powder with pozzolanic action, a powder with latent hydraulic properties, and stone powder (calcium carbonate powder), in the present invention, the amount of such powder is also a powder with physical properties that harden through a hydration reaction, such as cement. The high-strength admixture has a median diameter (D50; μm) measured using a laser diffraction / scattering particle size distribution analyzer (e.g., LA-920 (manufactured by Horiba, Ltd.)) using ethanol as a dispersion medium, and from the viewpoint of strength development, the median diameter (D50; μm) is preferably 1 μm or more, more preferably 5 μm or more, and preferably 50 μm or less, more preferably 40 μm or less.

[0039] <Aggregate> The hydraulic composition for centrifugal compaction of the present invention contains aggregate. Examples of aggregates include those selected from fine aggregates and coarse aggregates. Examples of fine aggregates include those specified under number 2311 in JIS A0203-2014. Examples of fine aggregates include river sand, land sand, mountain sand, sea sand, lime sand, silica sand, and crushed sands thereof, blast furnace slag fine aggregate, ferronickel slag fine aggregate, lightweight fine aggregates (artificial and natural), and recycled fine aggregate. Examples of coarse aggregates include those specified under number 2312 in JIS A0203-2014. Examples of coarse aggregates include river gravel, land gravel, mountain gravel, sea gravel, lime gravel, crushed stones thereof, blast furnace slag coarse aggregate, ferronickel slag coarse aggregate, lightweight coarse aggregates (artificial and natural), and recycled coarse aggregate. Different types of fine aggregates and coarse aggregates may be used in combination, or a single type may be used.

[0040] <Composition of hydraulic composition> In the hydraulic composition for centrifugal molding of the present invention, the content of component (A) is set to 1 / 4 of the hydraulic composition for centrifugal molding from the viewpoint of the fluidity of the hydraulic composition. 3 Preferably, the weight is 1.5 kg or more, more preferably 1.6 kg or more, even more preferably 1.7 kg or more, and preferably 3.0 kg or less, more preferably 2.5 kg or less, even more preferably 2.0 kg or less.

[0041] In the hydraulic composition for centrifugal molding of the present invention, the water / cement ratio (hereinafter sometimes referred to as W / B) is 15% by mass or more, preferably 17% by mass or more, and more preferably 19% by mass or more, from the viewpoint of the fluidity of the hydraulic composition, and is 25% by mass or less, preferably 24% by mass or less, and more preferably 23% by mass or less, from the viewpoint of the strength development of the hydraulic composition. In the hydraulic composition for centrifugal molding of the present invention, the water / hydraulic powder ratio (hereinafter sometimes referred to as W / C) is 10% by mass or more, preferably 14% by mass or more, more preferably 18% by mass or more, and even more preferably 20% by mass or more, from the viewpoint of the fluidity of the hydraulic composition, and is 25% by mass or less, preferably 23% by mass or less, and more preferably 21% by mass or less, from the viewpoint of the strength development of the hydraulic composition. Here, the water / cement ratio is the mass percentage (mass%) of water and cement in the hydraulic composition, and is calculated by water / cement x 100. The water / hydraulic powder ratio is the mass percentage (mass%) of water and hydraulic powder in the hydraulic composition, and is calculated by water / hydraulic powder x 100. The water / hydraulic powder ratio is calculated based on the amount of powder that has the physical property of hardening by hydration reaction. If the powder that has the physical property of hardening by hydration reaction contains high-strength admixtures in addition to cement, the amounts of these materials are also included in the amount of hydraulic powder. The same applies to other quantitative relationships of the hydraulic composition regarding hydraulic powder.

[0042] In the hydraulic composition for centrifugal molding of the present invention, the content of cement is set to 1 / 4 of the hydraulic composition for centrifugal molding from the viewpoint of the strength development of the hydraulic composition. 3 Preferably, the weight is 400 kg or more, more preferably 450 kg or more, even more preferably 500 kg or more, and preferably 700 kg or less, more preferably 650 kg or less, even more preferably 600 kg or less, and even more preferably 550 kg or less.

[0043] In the hydraulic composition for centrifugal molding of the present invention, the content of the high-strength admixture is set to 1 / m of the hydraulic composition for centrifugal molding from the viewpoint of the strength development of the hydraulic composition. 3 Preferably, the weight is 10 kg or more, more preferably 20 kg or more, even more preferably 40 kg or more, and preferably 200 kg or less, more preferably 150 kg or less, even more preferably 100 kg or less, even more preferably 80 kg or less, and even more preferably 60 kg or less.

[0044] When the hydraulic composition for centrifugal molding is concrete, the amount of coarse aggregate used is preferably 50% or more, more preferably 55% or more, even more preferably 60% or more, and preferably 100% or less, more preferably 90% or less, even more preferably 80% or less, from the viewpoints of developing the strength of the hydraulic composition, reducing the amount of hydraulic powder such as cement used, and improving the fillability into forms, etc. The bulk volume is preferably 50% or more, more preferably 55% or more, even more preferably 60% or more, and is preferably 100% or less, more preferably 90% or less, even more preferably 80% or less, from the viewpoints of improving the fillability into forms, etc. 3 It is the ratio of the volume of coarse aggregate (including voids) in the concrete. When the hydraulic composition for centrifugal molding is concrete, the amount of fine aggregate used is preferably 500 kg / m from the viewpoint of improving the filling property into a formwork or the like. 3 More preferably, 600 kg / m 3 More preferably, 650 kg / m 3 and preferably 1000 kg / m 3 Less than or equal to 900 kg / m 3 The following is the result. When the hydraulic composition for centrifugal molding is mortar, the amount of fine aggregate used is preferably 800 kg / m 3 More preferably, 900 kg / m 3 More preferably, 1000 kg / m 3 and preferably 2000 kg / m 3 or less, more preferably 1800 kg / m 3 or less, more preferably 1700 kg / m 3 The following is the result.

[0045] Examples of the hydraulic composition for centrifugal molding include concrete. Among them, concrete using cement is preferred. The hydraulic composition of the present invention is useful in any field such as self-leveling, refractories, plaster, lightweight or heavy-duty concrete, air-entraining, repair, prepacked, tremical, ground improvement, grout, and cold weather use.

[0046] The hydraulic composition for centrifugal molding of the present invention may contain conventional components such as cement dispersants, water-soluble polymer compounds, air-entraining agents, cement wetting agents, expansive agents, waterproofing agents, retarders, quick-setting agents, foaming agents, foaming agents, waterproofing agents, fluidizing agents, thickeners, flocculants, drying shrinkage-reducing agents, strength enhancers, hardening accelerators, preservatives, antifoaming agents, and rust inhibitors (excluding those corresponding to component (A)).

[0047] [Method for producing hydraulic composition] The present invention relates to a hydraulic composition comprising component (A), cement, aggregate, and water in a water / cement ratio of 15% by mass or more and 25% by mass or less, and a mixing amount of component (A) in a hydraulic composition. 3The present invention provides a method for producing a hydraulic composition for centrifugal molding, in which 1.5 kg to 3.0 kg of the component (A) is mixed in a mixing amount of 1.5 kg to 3.0 kg. By this method, the hydraulic composition for centrifugal molding of the present invention containing component (A), cement, aggregate, and water is produced. In the method for producing a hydraulic composition for centrifugal molding of the present invention, a high-strength admixture may be further mixed.

[0048] Specific examples and preferred embodiments of component (A), cement, high-strength admixture, and aggregate used in the method for producing the hydraulic composition for centrifugal molding of the present invention are the same as those described for the hydraulic composition for centrifugal molding of the present invention. The cement and high-strength admixture are used so that the W / B and W / C ratios are within the ranges described for the hydraulic composition for centrifugal molding of the present invention. The amount of aggregate used is also the same as that described for the hydraulic composition for centrifugal molding of the present invention. In the method for producing the hydraulic composition for centrifugal molding of the present invention, the contents of the components described for the hydraulic composition for centrifugal molding of the present invention can be appropriately applied by replacing the contents of the components with the mixing amounts. The matters described in relation to the hydraulic composition for centrifugal molding of the present invention can be appropriately applied to the method for producing the hydraulic composition for centrifugal molding of the present invention.

[0049] In the method for producing the hydraulic composition of the present invention, from the viewpoint of productivity, it is preferred to premix component (A) with water and then mix the mixture with cement.

[0050] The mixing of component (A), cement, optionally a high-strength admixture, aggregate, water, and other components used as needed can be carried out using a mixer such as a mortar mixer or a forced twin-shaft mixer. The mixing is preferably carried out for 1 minute or more, more preferably 2 minutes or more, and preferably 5 minutes or less, more preferably 3 minutes or less. In preparing the hydraulic composition, the materials and agents and the amounts thereof described in the hydraulic composition can be used.

[0051] The obtained hydraulic composition is further filled into a formwork, centrifugal molded, and then cured and hardened. Examples of the formwork include formwork for buildings, formwork for concrete products, etc. Methods for filling the formwork include a method of directly pouring the hydraulic composition from a mixer, a method of pumping the hydraulic composition into the formwork, etc.

[0052] During curing of the hydraulic composition, the hydraulic composition may be heat-cured to accelerate the hardening. Here, the heat-curing can be performed by maintaining the hydraulic composition at a temperature of 40°C or higher and 90°C or lower to accelerate the hardening.

[0053] [Method for producing a hardened product of a hydraulic composition] The present invention provides a method for producing a hardened product of a hydraulic composition, which comprises the following steps: Step 1: Mixing component (A), cement, aggregate, and water in a water / cement ratio of 15% by mass or more and 25% by mass or less, and mixing the component (A) in an amount of 1 / m of the hydraulic composition. 3 A process of mixing 1.5 kg to 3.0 kg of the mixture to obtain a hydraulic composition, and filling the obtained hydraulic composition into a formwork. Step 2: A step of clamping the hydraulic composition filled in the form obtained in step 1 by applying centrifugal force. Step 3: A step of allowing the clamped hydraulic composition obtained in step 2 to set in the formwork.

[0054] In the preparation of the hydraulic composition in step 1, a high-strength admixture may further be mixed. Specific examples and preferred embodiments of the component (A), cement, high-strength admixture, and aggregate used in the method for producing a hardened product of the hydraulic composition of the present invention are the same as those described for the hydraulic composition for centrifugal molding of the present invention. The cement and high-strength admixture are used so that the W / B and W / C ratios are within the ranges described for the hydraulic composition for centrifugal molding of the present invention. The amount of aggregate used is also the same as that described for the hydraulic composition for centrifugal molding of the present invention. In addition, in step 1 of the method for producing a hardened product of the hydraulic composition of the present invention, the contents of each component described for the hydraulic composition for centrifugal molding of the present invention can be appropriately applied by replacing the contents of each component with the mixing amounts. The matters described in relation to the hydraulic composition for centrifugal molding of the present invention and the method for producing the hydraulic composition for centrifugal molding can be appropriately applied to the method for producing a hardened product of the hydraulic composition of the present invention.

[0055] The method for producing a cured body of the present invention preferably includes the following step 4 in addition to steps 1 to 3. Step 4: A step of steam curing the hydraulic composition set in step 3 in a formwork.

[0056] The method for producing a cured body of the present invention can include the following step 5 in addition to steps 1 to 4. Step 5: After step 4, the hydraulic composition is cooled and removed from the formwork.

[0057] The method for producing a cured body of the present invention can include the following step 6 in addition to steps 1 to 5. Step 6: A step of curing the hardened hydraulic composition obtained in Step 5 at room temperature and normal pressure.

[0058] In step 1, a method of adding a mixture containing water and component (A) to a mixture containing aggregate and cement and mixing them is preferred because it allows for easy uniform mixing even when producing a hydraulic composition.

[0059] A specific method for step 1 includes mixing cement with an optional high-strength admixture and aggregate, adding a mixture containing water and component (A) in the amount described above, and kneading to prepare a hydraulic composition.

[0060] In step 1, the method for filling the obtained hydraulic composition into the form may be a method in which the kneaded hydraulic composition is discharged from the kneading means and manually poured into the form and leveled.

[0061] In step 2, the hydraulic composition filled in the form is clamped by applying centrifugal force, and it is preferable to change the centrifugal force at least once. In step 2, the hydraulic composition can be clamped by applying centrifugal force that changes stepwise. That is, in step 2, the hydraulic composition is clamped by changing the centrifugal force at least once, and further, the hydraulic composition can be clamped by applying centrifugal force that changes stepwise and becomes even larger stepwise.

[0062] In step 2, the hydraulic composition filled in the formwork is preferably clamped under a centrifugal force of 0.5 G or more. The centrifugal force in centrifugal molding is preferably 0.5 G or more and preferably 30 G or less, more preferably 25 G or less. From the viewpoints of energy cost reduction and moldability, it is preferable to maintain the centrifugal force in the range of 15 G or more and 30 G or less, further 25 G or less (also called high centrifugal force) for 1 minute or more.

[0063] Compaction by centrifugal force is carried out, for example, at a centrifugal force of 0.5 G or more and 30 G or less, for preferably 5 minutes or more, more preferably 7 minutes or more, even more preferably 9 minutes or more, and preferably 40 minutes or less. From the viewpoint of compacting the green body smoothly, compaction by maintaining a high centrifugal force, for example, a centrifugal force of 20 G or more, is carried out for preferably 1 minute or more, more preferably 3 minutes or more, even more preferably 5 minutes or more, and preferably 15 minutes or less. That is, in step 3, the hydraulic composition can be clamped in the mold at a centrifugal force of 0.5 G or more and 30 G or less, for preferably 5 minutes or more, more preferably 7 minutes or more, even more preferably 9 minutes or more, and preferably 40 minutes or less. Also, in step 3, compaction by maintaining a centrifugal force of 20 G or more can be carried out for preferably 1 minute or more, more preferably 3 minutes or more, even more preferably 5 minutes or more, and preferably 15 minutes or less.

[0064] Compaction using centrifugal force can be performed in stages, and from the viewpoint of formability, a method in which the centrifugal force G is increased stepwise is preferred. Compaction can be performed under the following step conditions until the desired centrifugal force is achieved. For example, in the case of five stages, in step 3, it is preferable to clamp the hydraulic composition under the following conditions: (1) in the first stage, a centrifugal force of 0.5 G or more but less than 2 G is used at an initial speed for more than 0 minutes and not more than 15 minutes; (2) in the second stage, a centrifugal force of 2 G or more but less than 5 G is used at a second speed for more than 0 minutes and not more than 15 minutes; (3) in the third stage, a centrifugal force of 5 G or more but less than 10 G is used at a third speed for more than 0 minutes and not more than 15 minutes; (4) in the fourth stage, a centrifugal force of 10 G or more but less than 20 G is used at a fourth speed for more than 0 minutes and not more than 15 minutes; and (5) in the fifth stage, a centrifugal force of 20 G or more but less than 30 G is used at a fifth speed for more than 0 minutes and not more than 15 minutes.

[0065] In step 3, the hydraulic composition obtained in step 2 is solidified. Specifically, the composition is cured in air for 3 to 4 hours after mixing.

[0066] In step 4, the hardened hydraulic composition placed in the form obtained in step 3 is steam cured. In step 4, steam curing is preferably carried out at a temperature of 40°C or higher and 90°C or lower, and more preferably at a temperature of 60°C or higher and 90°C or lower. Furthermore, in step 4, steam curing is preferably carried out after pre-curing. For example, the ambient temperature of the formwork filled with the hydraulic composition (hereinafter sometimes referred to as ambient temperature) can be set to room temperature, preferably from 10°C to 40°C, and pre-curing can be carried out by leaving it for from 1 hour to 4 hours, and then steam curing can be carried out by setting the ambient temperature to from 40°C to 90°C, or further to from 60°C to 90°C. Pre-curing was carried out as a "preliminary" step in the examples and comparative examples described below. The pre-curing is preferably for 1 hour or more from the viewpoint of suppressing a decrease in strength due to cracking of the hardened body. Furthermore, when the method for producing a cured body of the present invention includes step 5, steps 4 and 5 can be carried out consecutively under a series of temperature controls. Steam curing is performed by applying steam to the periphery of a form filled with a hydraulic composition and maintaining the temperature at a predetermined level for a certain period of time. After the application of steam, the steam curing period may be (1) a temperature increase period until the temperature reaches the predetermined level, (2) a period during which the temperature is maintained at the predetermined level for a certain period of time, and (3) a period during which the temperature is decreased after the temperature is maintained at the predetermined level for a certain period of time.

[0067] Specific steam curing conditions in the method for producing a hardened body of the present invention are as follows: in step 4, the ambient temperature of the formwork is raised to 60°C or higher and 85°C or lower at a rate of 10°C or higher and 30°C or lower per hour, and the raised temperature is maintained for 2 hours or higher and 8 hours or lower; and then, in step 5, the ambient temperature is cooled to room temperature, for example, 20°C, at a rate of 5°C or higher and 20°C or lower per hour, and the molded body is demolded. The temperature rise rate is preferably 20° C. per hour or less in order to prevent a decrease in strength due to cracking of the cured body. An example of preferred conditions is a method in which a formwork filled with a hydraulic composition is left to stand for 3 hours (pre-curing) at an ambient temperature of room temperature, for example, 10°C to 30°C, then the ambient temperature is raised to 70°C to 90°C at a rate of 20°C per hour, the raised temperature of 70°C to 90°C is maintained for 2 hours to 6 hours, and then the ambient temperature is cooled to room temperature, for example, 20°C, at a rate of 10°C per hour (step 4), and the formed body is left to stand at that temperature for 20 hours to 30 hours, after which it is demolded (step 5). It is also possible to further cure the material in an autoclave at approximately 180°C.

[0068] In step 6, the set hydraulic composition obtained in step 5 is cured at room temperature and atmospheric pressure. Specifically, it is stored at 20°C and atmospheric pressure.

[0069] The manufacturing method of the present invention includes a method for manufacturing a hardened product of a hydraulic composition, which includes steps 1 to 5, and in which the time from the start of preparation of the hydraulic composition to demolding in step 5 is 8 hours or more and 30 hours or less. Here, the start of preparation of the hydraulic composition refers to the time when cement and water first come into contact with each other.

[0070] The hardened product of the hydraulic composition obtained by the method for producing a hardened product of the present invention can be used as a centrifugally molded concrete product, specifically, piles, poles, Hume pipes, etc. The hardened product of the hydraulic composition obtained by the method for producing a hardened product of the present invention has excellent formability for a hydraulic composition after a certain time (15 to 60 minutes) has passed since mixing, so that the product has little unevenness on the inner surface and edge surface, has excellent surface appearance, and furthermore, the smooth finish of the inner surface of the product reduces obstacles to cutting machines during pile driving and core excavation. [Example]

[0071] The components (A) and (A') (comparison components to component (A)) shown in Table 1 were as follows:

[0072] Component (A) (a-1): A copolymer synthesized according to Production Example A1 in paragraph 0048 and Production Example C1 in paragraph 0058 of JP 2009-161379 A, ​​monomer (A1) / monomer (A2) / monomer (A3) = fumaric acid, maleic anhydride / monomer obtained by adding ethylene oxide to a polyamidepolyamine, which is a condensate of adipic acid and a polyalkylenepolyamine, bonded to fumaric acid and maleic anhydride via an amide bond / methallyl polyethylene glycol (50) polypropylene glycol (2) ether (block adduct, the average number of moles added is in parentheses) = 13.8% by mass / 2.7% by mass / 83.5% by mass, weight average molecular weight = 26,000, and the obtained polymer is a sodium salt.

[0073] Component (A') (a'-1): Copolymer 1 described in paragraph 0082 of JP 2020-66553 A, sodium acrylate / sodium methacrylate / methoxypolyethylene glycol (45) monomethacrylate (the average number of moles added of the monomers is in parentheses) = 29 mol% / 45 mol% / 26 mol%, weight average molecular weight = 30,000, the obtained polymer is a sodium salt.

[0074] (1) Concrete mix The concrete mix is ​​shown in Table 1. The concrete materials used were as follows: W / B is the water / cement ratio (mass%). In Table 1, the amounts of cement (C), tap water (W), high-strength admixture (P), sand (S), and gravel (G) added are calculated based on the amount of concrete per 1 m of concrete. 3 The amount added (kg) is Cement (C): Taiheiyo Cement Corporation, specific gravity 3.14 Tap water (W): The amount shown in Table 1 was used as the weight including component (A) or component (A'). High-strength admixture (P): Denka Σ2000 (specific gravity 2.45, manufactured by Denki Kagaku Kogyo Co., Ltd.) Sand (S): from Koka, Shiga Prefecture, specific gravity 2.58 Gravel (G): from Ieshima, Hyogo Prefecture, specific gravity 2.63

[0075] (2) Concrete preparation A composition containing component (A) or (A') and water was prepared in the amounts shown in Table 1, and the composition was added to the water (W) in the concrete mix ingredients and stirred to prepare mixing water. The concrete was prepared by adding gravel, about half the amount of sand, a mixture of cement and high-strength admixture, and the remaining amount of sand, in that order, to a forced twin-screw mixer (manufactured by KYC Corporation) and dry mixing for 30 seconds. The prepared mixing water was then quickly added, and the concrete was obtained by mixing for 240 seconds.

[0076] (3) Evaluation of concrete fluidity Immediately after mixing, the concrete was measured for slump (cm) in accordance with JIS A 1101. The results are shown in Table 1.

[0077] (4) Sludge collection Ten minutes after mixing, the concrete was placed into a centrifugal molding formwork (inner diameter 20 cm, outer diameter 25 cm, height 40 cm) and sealed with a rubber stopper. It was then centrifuged at an initial speed of 1 G for 2 minutes, second speed at 3 G for 2 minutes, third speed at 7 G for 2 minutes, fourth speed at 15 G for 3 minutes, and fifth speed at 25 G for 3 minutes. After centrifugal compaction, the rubber stopper of the centrifugal molding formwork was then opened, and the cylindrical compacted body still in the formwork was tilted 45° vertically, and the resulting sludge was collected using a 500 mL disposable cup.

[0078] (5) Measurement of sludge flow time The sludge collected by method (4) was filled into a glass funnel with an outer diameter of 75 mm at the top, an outer diameter of 8 mm at the base, and a base length of 75 mm, and the flow time was measured as an index of sludge viscosity. The results are shown in Table 1. The shorter the flow time, the lower the viscous resistance to flow, and therefore the lower the viscosity can be evaluated.

[0079] [Table 1]

[0080] In Table 1, the amount of component (A) or (A') added is per 1 m of concrete. 3 The amount added (kg) is the amount of solids (effective content) added.

[0081] In Table 1, Examples 1 and 2, which used component (A) of the present invention, showed a shorter flow-down time and lower viscosity of sludge generated by fluctuations in water volume (fluctuations in W / B) than Comparative Examples 1 to 3, which used component (A'). This is thought to be because component (A), which exhibits excellent adsorption and dispersibility for the low-density hydration products contained in the sludge, effectively fluidized and reduced the viscosity of the sludge.

Claims

1. A hydraulic composition for centrifugal molding containing the following component (A), cement, aggregates including coarse aggregate, and water, wherein the water / cement ratio is 15% by mass or more and 25% by mass or less, the amount of coarse aggregate used is 50% by bulk volume or more, and the content of component (A) is 100% by mass per 1 m of the hydraulic composition for centrifugal molding. ３ The hydraulic composition for centrifugal molding has a hardness of 1.5 kg or more and 3.0 kg or less. Component (A): A copolymer containing, as constituent monomers, one or more monomers (A1) selected from fumaric acid, maleic acid (anhydride), and salts thereof, a monomer (A2) represented by the following general formula (A2), and a monomer (A3) represented by the following general formula (A3), wherein, among the constituent monomers of the copolymer, the proportion of monomer (A1) is 1% by mass or more and 30% by mass or less, the proportion of monomer (A2) is 1% by mass or more and 20% by mass or less, and the proportion of monomer (A3) is 50% by mass or more and 90% by mass or less. 【Chemistry 1】 [In general formula (A2), R ２１ａ , R ２２ａ , R ２３ａ may be the same or different and are a hydrogen atom, a methyl group, or COOM, M is a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2 atom), an ammonium group, an alkylammonium group, or a substituted alkylammonium group, and Z is a group that bonds, via an amide bond, to a carbon atom in the main chain of a polyamidepolyamine obtained by condensing a dibasic acid with a polyalkylenepolyamine and / or a modified polyamidepolyamine obtained by adding 0.1 mol to 10 mol of an alkylene oxide having from 2 to 4 carbon atoms per equivalent of the active imino group, amino group, or amide residue of the polyamidepolyamine. 【Chemistry 2】 [In general formula (A3), R ３１ａ , R ３２ａ may be the same or different and are a hydrogen atom or a methyl group, R ３３ａ is a hydrogen atom or -COO(AO) ｎ X, where X is an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, AO is a group selected from an ethyleneoxy group and a propyleneoxy group, n is the average number of moles of AO added and is a number of 5 to 150, p is a number of 0 to 2, and q is a number of 0 or 1.

2. 2. The hydraulic composition for centrifugal molding according to claim 1, wherein the proportion of the monomer (A1) in the constituent monomers of the copolymer of component (A) is 8% by mass or more and 30% by mass or less.

3. 3. The hydraulic composition for centrifugal molding according to claim 1, wherein the total proportion of the monomers (A1), (A2) and (A3) in the constituent monomers of the copolymer of component (A) is 95 mass% or more.

4. The content of component (A) is 1 m of the hydraulic composition for centrifugal molding. ３ The hydraulic composition for centrifugal molding according to any one of claims 1 to 3, wherein the weight is 1.5 kg or more and 2.5 kg or less.

5. The content of high-strength admixture in 1 m of hydraulic composition for centrifugal molding is ３ The hydraulic composition for centrifugal molding according to any one of claims 1 to 4, wherein the weight is 10 kg or more and 200 kg or less.

6. A method for producing a hardened hydraulic composition, comprising the following steps: Step 1: Mixing the following component (A), cement, aggregate including coarse aggregate, and water in a water / cement ratio of 15% by mass or more and 25% by mass or less, the amount of coarse aggregate used being 50% by volume or more, and the mixing amount of component (A) is 1 m of hydraulic composition. ３ a step of mixing 1.5 kg to 3.0 kg of the mixture to obtain a hydraulic composition, and filling the obtained hydraulic composition into a formwork. Step 2: A step of clamping the hydraulic composition filled in the form obtained in step 1 by applying centrifugal force. Step 3: A step of allowing the clamped hydraulic composition obtained in step 2 to set in the formwork. Component (A): A copolymer containing, as constituent monomers, one or more monomers (A1) selected from fumaric acid, maleic acid (anhydride), and salts thereof, a monomer (A2) represented by the following general formula (A2), and a monomer (A3) represented by the following general formula (A3), wherein, among the constituent monomers of the copolymer, the proportion of monomer (A1) is 1% by mass or more and 30% by mass or less, the proportion of monomer (A2) is 1% by mass or more and 20% by mass or less, and the proportion of monomer (A3) is 50% by mass or more and 90% by mass or less. 【Transformation 3】 [In general formula (A2), R ２１ａ , R ２２ａ , R ２３ａ may be the same or different and are a hydrogen atom, a methyl group, or COOM, M is a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2 atom), an ammonium group, an alkylammonium group, or a substituted alkylammonium group, and Z is a group that bonds, via an amide bond, to a carbon atom in the main chain of a polyamidepolyamine obtained by condensing a dibasic acid with a polyalkylenepolyamine and / or a modified polyamidepolyamine obtained by adding 0.1 mol to 10 mol of an alkylene oxide having from 2 to 4 carbon atoms per equivalent of the active imino group, amino group, or amide residue of the polyamidepolyamine. 【Chemistry 4】 [In general formula (A3), R ３１ａ , R ３２ａ may be the same or different and are a hydrogen atom or a methyl group, R ３３ａ is a hydrogen atom or -COO(AO) ｎ X, where X is an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, AO is a group selected from an ethyleneoxy group and a propyleneoxy group, n is the average number of moles of AO added and is a number of 5 to 150, p is a number of 0 to 2, and q is a number of 0 or 1.

7. 7. The method for producing a hardened hydraulic composition according to claim 6, wherein the proportion of the monomer (A1) in the constituent monomers of the copolymer of component (A) is 8% by mass or more and 30% by mass or less.

8. 8. The method for producing a hydraulic composition cured product according to claim 6 or 7, wherein the total proportion of the monomer (A1), the monomer (A2) and the monomer (A3) in the constituent monomers of the copolymer of component (A) is 95 mass% or more.

9. In step 1, the mixing amount of component (A) is 1 m of hydraulic composition. ３ The method for producing a hardened hydraulic composition according to any one of claims 6 to 8, wherein the weight of the hardened hydraulic composition is 1.5 kg or more and 2.5 kg or less.

10. The method for producing a hardened hydraulic composition according to any one of claims 6 to 9, further comprising the following step 4 after step 3: Step 4: Steam curing the set hydraulic composition obtained in step 3 in a formwork.

11. The method for producing a hardened hydraulic composition according to claim 10, wherein in step 4, the steam curing temperature is 40°C or higher and 90°C or lower.

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