Additive for hydraulic composition

Abstract

To provide an additive for a hydraulic composition that prevents laitance formation and shape deformation in the hydraulic composition.SOLUTION: An additive for a hydraulic composition comprises: (A) carboxymethyl cellulose or a salt thereof (component (A)); and (B) a halide (component (B)), wherein the ratio (B) / (A) of the content of the component (B) to the content of the component (A) is 0.07 mass% or more and 3.5 mass% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an additive for a hydraulic composition, a hydraulic composition, a method for producing a hydraulic composition, and a spraying method.

Background Art

[0002] In order to prevent the collapse of exposed natural ground such as tunnel excavation, a spraying method using quick-setting concrete or quick-setting mortar in which a quick-setting agent is blended into concrete is carried out. In this method, usually, sprayed concrete is prepared in a metering and mixing plant for cement, aggregate, and water installed at the excavation work site, and it is transported by an agitator truck and transferred to a spraying machine. Then, the sprayed concrete and the quick-setting agent are joined and mixed by a line that pneumatically transports the sprayed concrete to the discharge port by a pump of the spraying machine and a line that pneumatically transports the quick-setting agent from the other side through a joining pipe provided in the middle, and it is a method of spraying onto the natural ground surface as quick-setting sprayed concrete until it reaches a predetermined thickness.

[0003] Patent Document 1 discloses a fireproof spraying material mainly composed of a premix material comprising 20 to 70% by weight of cement, 5 to 35% by weight of inorganic elastic granular aggregate, 3 to 20% by weight of lightweight spherical aggregate, 5 to 30% by weight of inorganic foam particles, and the balance being a thickener. Patent Document 2 discloses a liquid quick-setting agent containing aluminum sulfate, water-soluble cellulose ether, and water, in which insoluble particles are dispersed in the liquid at -10 to 40°C and 90% or more of the liquid is suspended by volume ratio, and a cement composition containing the liquid quick-setting agent and a spraying method using the cement composition.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention provides an additive for hydraulic compositions, a hydraulic composition, a method for producing a hydraulic composition, and a spraying method that suppress the generation and shape change of noro in hydraulic compositions.

Means for Solving the Problems

[0006] The present invention relates to an additive for hydraulic compositions containing (A) carboxymethyl cellulose or a salt thereof [hereinafter referred to as component (A)], and (B) a halide [hereinafter referred to as component (B)], wherein the ratio (B) / (A) of the content of component (B) to the content of component (A) is 0.07% by mass or more and 3.5% by mass or less.

[0007] The present invention also relates to a hydraulic composition containing component (A), component (B), hydraulic powder, and water, wherein the ratio (B) / (A) of the content of component (B) to the content of component (A) is 0.07% by mass or more and 3.5% by mass or less.

[0008] The present invention further relates to a method for producing a hydraulic composition, which comprises mixing component (A), component (B), hydraulic powder, and water so that the ratio (B) / (A) of the mixing amount of component (B) to the mixing amount of component (A) is 0.07% by mass or more and 3.5% by mass or less.

[0009] The present invention also relates to a spraying method for spraying the above hydraulic composition onto a target surface.

Advantages of the Invention

[0010] According to the present invention, there are provided an additive for hydraulic compositions, a hydraulic composition, a method for producing a hydraulic composition, and a spraying method that suppress the generation and shape change of noro in hydraulic compositions.

Embodiments for Carrying Out the Invention

[0011] The present invention relates to an additive for hydraulic compositions, a hydraulic composition, a method for producing a hydraulic composition, and a spraying method, and particularly relates to an additive for hydraulic compositions, a hydraulic composition, a method for producing a hydraulic composition, and a spraying method used when spraying quick-setting concrete or quick-setting mortar on tunnels such as roads, railways, and water conduits, and on slopes formed by excavating natural ground, filling, etc. Note that the hydraulic composition referred to in the present invention collectively refers to cement mortar and cement concrete.

[0012] Although the mechanism by which the additive for hydraulic compositions and the hydraulic composition of the present invention suppress the generation and shape change of noro in the hydraulic composition is not clear, it is presumed as follows. When the carboxymethyl cellulose or its salt of component (A) does not dissolve well in water and forms lumps, the dispersibility in the hydraulic composition decreases, and it may be difficult to uniformly act the carboxymethyl cellulose or its salt on the hydraulic composition. On the other hand, the additive for hydraulic compositions of the present invention is presumed to suppress the generation of lumps in the mixture of component (A) and water by suppressing the water absorption of component (A) by the action of the halide of component (B), and thereby, it is possible to more uniformly disperse component (A) in the hydraulic composition. Moreover, it is presumed that component (A) adsorbs to the hydraulic particles and has an aggregating effect on the hydraulic particles. Thereby, it is presumed that the generation of noro in the hydraulic composition is suppressed or the shape retention of the hydraulic composition is improved. Note that the additive for hydraulic compositions, the hydraulic composition, the method for producing a hydraulic composition, and the spraying method of the present invention are not limited to the above action mechanism at all. In addition, in this specification, noro refers to a mixture containing powder separated from the hydraulic composition and water, that is, the paste component. Noro has a large amount of water, and if the amount of water locally increases due to the generation of noro, the strength of the hydraulic composition may decrease.

[0013] <Additive for Hydraulic Composition> The additive for the hydraulic composition of the present invention contains (A) carboxymethyl cellulose or its salt [component (A)], and (B) a halide [component (B)].

[0014] <Component (A)> (Component (A)) is carboxymethyl cellulose or its salt. One or more kinds of component (A) can be used.

[0015] (Component (A)) is a derivative polymer of cellulose having a carboxy group. Examples of the salt of carboxymethyl cellulose include alkali metal salts such as sodium salt and potassium salt, and ammonium salt. From the viewpoint of easy availability, etc., the salt of carboxymethyl cellulose is preferably an alkali metal salt of carboxymethyl cellulose, and more preferably sodium carboxymethyl cellulose (sodium carboxymethyl cellulose).

[0016] From the viewpoint of suppressing the generation of noro and shape change of the hydraulic composition, the degree of etherification of component (A) is preferably 0.5 or more, more preferably 0.55 or more, still more preferably 0.6 or more, and from the same viewpoint, preferably 1.5 or less, more preferably 1.3 or less, still more preferably 1.0 or less. The degree of etherification of component (A) refers to the degree of substitution of carboxymethyl groups per glucose unit of component (A). When component (A) is sodium carboxymethyl cellulose, its degree of etherification is measured by the following method according to, for example, the CMC Industrial Association analysis method (ashing method). When component (A) is a salt other than sodium, the degree of etherification of component (A) can be measured by the same method.

[0017] [Measurement of the degree of etherification of sodium carboxymethyl cellulose] Accurately weigh 1 g of sodium carboxymethyl cellulose, put it into a magnetic crucible, and ashing at 600 °C. Titrate the sodium oxide produced by ashing with N / 10 sulfuric acid using phenolphthalein as an indicator, and put the titration volume Y mL per 1 g of sodium carboxymethyl cellulose into the following formula for calculation, which can show the determined degree of etherification. Degree of etherification = (162 × Y) / (10,000 - 80 × Y)

[0018] (Component (A), from the viewpoint of suppressing the generation and shape change of the slime of the hydraulic composition, when it is a 1 mass% aqueous solution, the viscosity at 25 °C is preferably 20 mPa·s or more, more preferably 40 mPa·s or more, still more preferably 200 mPa·s or more, and even more preferably 2,000 mPa·s or more. And from the same viewpoint, it is preferably 7,000 mPa·s or less, more preferably 6,000 mPa·s or less, still more preferably 5,000 mPa·s or less. The above viscosity is measured with a B-type viscometer (VISCOMETER, MODEL BM, manufactured by Tokyo Keiki Co., Ltd. (former Tokimec Co., Ltd.), rotor No. 2) at a rotational speed of 60 rpm.

[0019] (Component (A) may be a solid, and more particularly, a powdery carboxymethyl cellulose or its salt. In the present invention, "powdery" means being in a solid state, typically referring to powders such as fine powder, powder, fine granule, granule, etc. The powdery component (A) may be a polymer having the following average particle diameter. When component (A) is a solid, and more particularly, powdery, from the viewpoint of suppressing the generation and shape change of the slime of the hydraulic composition, the average particle diameter of component (A) is preferably 0.5 μm or more, more preferably 1.0 μm or more, still more preferably 5.0 μm or more. And from the same viewpoint, it is preferably 500 μm or less, more preferably 300 μm or less, still more preferably 150 μm or less. The average particle diameter of component (A) is measured by the following method.

[0020] <Measurement method of the average particle diameter of component (A)> Weigh the solid, and more particularly the powdery (A) component, onto a slide glass and photograph it with a digital microscope (DSX1000, manufactured by OLYMPUS Corporation, magnification: 180 times). Measure the diameters of 100 powder particles of the (A) component from the obtained image, and calculate the average particle diameter from the arithmetic mean of these values. When measuring the diameter of the powder particles of the (A) component, if the powder particles are circular, use the diameter; if the powder particles of the (A) component are elliptical, amorphous, or of a high aspect ratio shape, use the longest part as the diameter. Also, when the average particle diameter of the (A) component is less than 30 μm, take an image with the magnification of the digital microscope set to 600 times, measure the diameter of the powder particles of the (A) component, and calculate the average particle diameter of the (A) component.

[0021] From the viewpoint of suppressing the generation and shape change of the noro of the hydraulic composition, the weight average molecular weight of the (A) component is preferably 10,000 or more, more preferably 100,000 or more, still more preferably 400,000 or more, even more preferably 800,000 or more, even more preferably 1,500,000 or more, and preferably 20,000,000 or less, more preferably 10,000,000 or less, still more preferably 6,000,000 or less. This weight average molecular weight is measured according to the following method for measuring the weight average molecular weight.

[0022] <Method for Measuring Weight Average Molecular Weight> The weight average molecular weight of the (A) component is measured by GPC (gel permeation chromatography), and the weight average molecular weight (Mw) can be determined using a conversion standard substance. The measurement conditions for GPC are shown below. · Apparatus: HLC - 8320 GPC (manufactured by Tosoh Corporation, detector - integrated type) · Column: Manufactured by Tosoh Corporation, product name: TSK - GEL guardcolumn PWXL Manufactured by Tosoh Corporation, product name: TSK - GEL GMPWXL Manufactured by Tosoh Corporation, product name: TSK - GEL GMPWXL · Mobile phase: 0.2 mol / L phosphate buffer (aqueous solution of potassium dihydrogen phosphate and disodium hydrogen phosphate, pH = 7) / acetonitrile = 90 / 10 (volume ratio) · Detector: differential refractive index detector · Column temperature: 40 °C · Flow rate: 0.5 mL / min · Conversion standard substance: polyethylene oxide [manufactured by Tosoh Corporation] · Sample: Ultra-pure water is added to an aqueous polymer solution containing 5 mg of solid content, and the total liquid volume is adjusted to 10 mL. 100 μL is taken from this prepared solution and injected into the column.

[0023] (Component (A)) From the viewpoint of suppressing the generation of noro and shape change of the hydraulic composition, one or more selected from the group consisting of carboxymethyl cellulose and sodium carboxymethyl cellulose are preferable, and sodium carboxymethyl cellulose is more preferable. Examples of commercially available sodium carboxymethyl cellulose used as component (A) include CMC Daicel series manufactured by Daicel Corporation, Sunrose series manufactured by Nippon Paper Industries Co., Ltd., and the like.

[0024] <(Component (B))> (Component (B)) is a halide. Examples of the halide include fluoride, chloride, bromide, iodide, etc., and chloride is preferable. The halide of component (B) is preferably an inorganic salt. However, component (B) excludes component (C) which is a quick-setting agent. Component (B) can be used alone or in combination of two or more. (Component (B)) From the viewpoint of suppressing the generation of noro and shape change of the hydraulic composition, halides of alkali metals, halides of alkaline earth metals, halides of quaternary ammonium, halides of other metal ions, more specifically, chlorides of alkali metals, chlorides of alkaline earth metals, chlorides of quaternary ammonium, chlorides of other metal ions can be mentioned.

[0025] (B) component is preferably at least one selected from chlorides of alkali metals, chlorides of alkaline earth metals, and chlorides of quaternary ammonium from the viewpoint of suppressing the generation and shape change of slump of the hydraulic composition. More preferably, it is at least one selected from sodium chloride, potassium chloride, calcium chloride, and ammonium chloride. Even more preferably, it is at least one selected from sodium chloride, potassium chloride, and ammonium chloride.

[0026] <Composition, etc.> The additive for hydraulic composition of the present invention contains the (A) component, preferably 96% by mass or more, more preferably 98% by mass or more, even more preferably 99.5% by mass or more, still more preferably 99.7% by mass or more, and from the same viewpoint, preferably 99.93% by mass or less, more preferably 99.90% by mass or less, even more preferably 99.85% by mass or less, from the viewpoint of suppressing the generation and shape change of slump of the hydraulic composition. The preferred content of the above (A) component may be the preferred content of the (A) component in the additive for hydraulic composition that does not contain the (C) component, which will be described in detail later. When the additive for hydraulic composition contains the (C) component, the preferred content of the above (A) component may be the preferred content of the (A) component in the additive for hydraulic composition excluding the (C) component.

[0027] The additive for hydraulic composition of the present invention contains the (B) component, preferably 0.08% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and from the viewpoint of reducing the influence of chloride ions on steel materials, preferably 3.0% by mass or less, more preferably 2.0% by mass or less, even more preferably 1.0% by mass or less. The preferred content of the above (B) component may be the preferred content of the (B) component in the additive for hydraulic composition that does not contain the (C) component, which will be described in detail later. When the additive for hydraulic composition contains the (C) component, the preferred content of the above (B) component may be the preferred content of the (B) component in the additive for hydraulic composition excluding the (C) component.

[0028] From the viewpoint of suppressing the generation of slump and shape change of the hydraulic composition, the total content of component (A) and component (B) in the additive for hydraulic composition of the present invention is preferably 85% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and, for example, 100% by mass or less, and further 95% by mass or less. The additive for hydraulic composition of the present invention may be a composition containing 100% by mass in total of component (A) and component (B), that is, an additive for hydraulic composition composed of component (A) and component (B). The preferable range of the total content of the above component (A) and component (B) may be the preferable range of the total content of component (A) and component (B) in the additive for hydraulic composition not containing component (C) which will be described in detail later. Further, when the additive for hydraulic composition contains component (C), the preferable range of the total content of the above component (A) and component (B) may be the preferable range of the total content of component (A) and component (B) in the additive for hydraulic composition excluding component (C).

[0029] In the additive for hydraulic composition of the present invention, the ratio (B) / (A) of the content of component (B) to the content of component (A) is 0.07% by mass or more, preferably 0.10% by mass or more, more preferably 0.12% by mass or more from the viewpoint of suppressing the generation of slump and shape change of the hydraulic composition, and, from the same viewpoint, 3.5% by mass or less, preferably 3.0% by mass or less, more preferably 2.5% by mass or less.

[0030] <(C) component> The additive for hydraulic composition of the present invention may optionally contain a (C) flash setting agent [hereinafter also referred to as component (C)]. Component (C) can be used alone or in combination of two or more. The flash setting agent can be used in any form such as powder form, liquid form, or a combination thereof. Examples of the flash setting agent include one or more flash setting agents selected from cement mineral-based flash setting agents and aluminum-based flash setting agents.

[0031] Examples of the cement mineral-based flash setting agent of component (C) include one or more selected from calcium aluminate, calcium sulfoaluminate, and calcium aluminate. Examples of the aluminum-based quick-setting agent for component (C) include one or more selected from aluminum salts including aluminum hydroxide, sodium aluminate, potassium aluminate, aluminum sulfate, aluminum chloride, potassium aluminum sulfate, potassium alum, iron alum, and ammonium iron alum. From the viewpoint of strength development, component (C) is preferably one or more selected from calcium aluminate, calcium sulfoaluminate, calcium aluminate, aluminum sulfate, sodium aluminate, and aluminum sulfate, more preferably one or more selected from calcium aluminate, calcium sulfoaluminate, and aluminum sulfate, still more preferably one or more selected from calcium aluminate and aluminum sulfate, and even more preferably those containing aluminum sulfate. Component (C) may contain gypsum, alkali carbonates such as sodium carbonate, potassium carbonate, and sodium hydrogen carbonate, sodium sulfate, and calcium hydroxide.

[0032] As the quick-setting agent for component (C), those such as Denka's Denka Natomic series, Denka Natomic US-32, Denka Natomic US-50, Denka Natomic TYPE-5, Denka Natomic TYPE-10, Denka Natomic Z, Natomic L, Natomic LSA, Natomic USS, Natomic HSS, Denka Σ Shot V, Pacific Material Co., Ltd.'s Pacific Shot Master series, Pacific Shot Master A, Pacific Shot Master A (for high strength), Pacific Shot Master H, Pozolith Solutions Co., Ltd.'s Master Rock series, Master Rock SA161, Master Rock SA167, Master Rock SA178, Master Rock SA143, Master Rock SA446, Seek Japan Co., Ltd.'s Signit series, Signit P10AF, Signit L53AF, Signit U, etc. can be used.

[0033] <Calcium aluminate> Calcium aluminate (hereinafter referred to as CA) is a general term for compounds mainly composed of CaO and Al₂O₃ and having hydration activity. A part of CaO and / or Al₂O₃ is replaced by alkali metal oxides, alkaline earth metal oxides, silicon oxide, titanium oxide, iron oxide, alkali metal halides, alkaline earth metal halides, alkali metal sulfates, and alkaline earth metal sulfates, etc. Or a substance in which these are dissolved in a small amount in a compound mainly composed of CaO and Al₂O₃. CA may be either crystalline or amorphous.

[0034] Specific examples of crystalline CA are C₃A when CaO is C and Al₂O₃ is A, C₁₄A₅ in which an alkali metal is dissolved in it, CA, C₁₂A₇, C₁₁A₇·CaF₂, C₄A·Fe₂O₃, and C₃A₃·CaSO₄, etc. Also, these compounds may contain, for example, Na₂O, K₂O, and Li₂O. Amorphous calcium aluminate is preferred because of its good flash setting property.

[0035] Note that the calcium aluminate used in this embodiment may be contaminated with trace amounts of alkali metals and / or alkaline earth metals from industrial raw materials, and there is a possibility that CA containing these alkali metals and / or alkaline earth metals is partially generated. However, it is not restricted by the presence of these small amounts of alkali metals and / or alkaline earth metals at all.

[0036] The CaO / Al₂O₃ molar ratio of calcium aluminate is not particularly limited. Considering the very early strength development property, the molar ratio is preferably 2.0 or more and 3.0 or less, and more preferably 2.2 or more and 2.8 or less. When the molar ratio is 2.0 or more, the very early setting property can be improved. When it is 3.0 or less, it is easier to obtain good long-term strength development property.

[0037] The Blaine specific surface area of calcium aluminate (hereinafter sometimes simply referred to as "Blaine") is preferably 4,000 cm 2 / g or more and 8,000 cm 2 / g or less, and 5,000 cm 27,000 cm / g or more 2 It is more preferably 4,000 cm / g or less. When the specific surface area is 4,000 cm 2 / g or more and 8,000 cm 2 / g or less, the initial strength development property can be easily obtained, and the workability of the mortar and / or concrete during spraying can be improved.

[0038] <Potassium Alum> Potassium alum is effective for promoting the loss of fluidity immediately after mixing cement mortar or cement concrete and for promoting the strength development property in about one day. Potassium alum is not particularly limited, and for example, any potassium alum such as potassium alum, chrome alum, iron alum, ammonium alum, sodium alum, natural alum, etc. can be used or used in combination. Particularly as those that cause the loss of fluidity of cement mortar or cement concrete, it is preferable to contain at least one selected from the group consisting of potassium alum, sodium alum, and ammonium alum.

[0039] <Gypsum> As the gypsum, any of anhydrous, hemihydrate, and dihydrate gypsum can be used. Among these, anhydrous gypsum is preferable from the viewpoint of good strength development property. The particle size of the gypsum is preferably 2,000 cm 2 / g or more in terms of Blaine specific surface area, and more preferably 3,000 cm 2 / g or more and 6,000 cm 2 / g or less. The Blaine specific surface area value in this specification can be determined in accordance with JIS R 5201 (Physical Testing Methods for Cement).

[0040] <Calcium Hydroxide> Calcium hydroxide is an effective material for ensuring extremely early fluidity reduction and long-term strength development. Calcium hydroxide is not particularly limited, but includes slaked lime generated when quicklime hydrates and carbide slag generated when carbide hydrates. Also, commercially available calcium hydroxide can be used, and any combination of the above is also possible.

[0041] The Blaine specific surface area of calcium hydroxide is preferably 5,000 cm 2 / g or more and 15,000 cm 2 / g or less, and more preferably 7,000 cm 2 / g or more and 13,000 cm 2 / g or less. When the specific surface area is 5,000 cm 2 / g or more and 15,000 cm 2 / g or less, flash setting properties and long-term strength development can be ensured, and good initial strength development can be easily obtained.

[0042] <Alkali carbonate> Alkali carbonate refers to alkali metal carbonate salts and can significantly improve the setting properties and initial strength development of powdered flash setters. Alkali carbonate is not particularly limited, and examples include lithium carbonate, sodium carbonate, sodium sesquicarbonate, potassium carbonate, sodium bicarbonate, sodium hydrogen carbonate, etc. Particularly effective for setting and initial strength development are sodium carbonate, potassium carbonate, sodium sesquicarbonate, sodium bicarbonate, and sodium hydrogen carbonate, and it is also possible to combine one or more of these. Preferably, it is at least one selected from the group consisting of sodium carbonate, sodium sesquicarbonate, sodium bicarbonate, and potassium carbonate.

[0043] When the additive for the hydraulic composition of the present invention contains the component (C), the additive for the hydraulic composition of the present invention contains the component (A) preferably at 0.1% by mass or more, more preferably at 0.2% by mass or more, still more preferably at 0.3% by mass or more, and, from the viewpoint of suppressing the generation of slime and shape change of the hydraulic composition, preferably at 5% by mass or less, more preferably at 3% by mass or less, still more preferably at 2% by mass or less, and even more preferably at 0.9% by mass or less.

[0044] When the additive for the hydraulic composition of the present invention contains the component (C), the additive for the hydraulic composition of the present invention contains the component (B) preferably at 0.0002% by mass or more, more preferably at 0.0004% by mass or more, still more preferably at 0.0005% by mass or more, and, from the viewpoint of suppressing the generation of slime and shape change of the hydraulic composition, preferably at 0.005% by mass or less, more preferably at 0.003% by mass or less, still more preferably at 0.001% by mass or less.

[0045] When the additive for the hydraulic composition of the present invention contains the component (C), the additive for the hydraulic composition of the present invention contains the components (A) and (B) in total preferably at 0.1% by mass or more, more preferably at 0.2% by mass or more, still more preferably at 0.3% by mass or more, and, for example, at 3% by mass or less, further at 1% by mass or less, further at 0.8% by mass or less, and further at 0.6% by mass or less from the viewpoint of suppressing the generation of slime and shape change of the hydraulic composition.

[0046] When the additive for the hydraulic composition of the present invention contains the component (C), in the additive for the hydraulic composition of the present invention, the ratio (B) / (A) of the content of the component (B) to the content of the component (A) is 0.07% by mass or more, preferably 0.10% by mass or more, more preferably 0.12% by mass or more, and, from the same viewpoint, 3.5% by mass or less, preferably 3.0% by mass or less, and more preferably 2.5% by mass or less.

[0047] When the additive for the hydraulic composition of the present invention contains the component (C), the additive for the hydraulic composition of the present invention preferably contains the component (C) in an amount of 90% by mass or more, more preferably 95% by mass or more, still more preferably 99% by mass or more, and, from the same viewpoints, preferably 99.99% by mass or less, more preferably 99.97% by mass or less, still more preferably 99.95% by mass or less, from the viewpoints of suppressing the generation of slime and shape change of the hydraulic composition and the strength development property.

[0048] When the additive for the hydraulic composition of the present invention contains the component (C), in the additive for the hydraulic composition of the present invention, the ratio (C) / (A) of the content of the component (C) to the content of the component (A) is preferably 4,000% by mass or more, more preferably 10,000% by mass or more, still more preferably 18,000% by mass or more, and, from the viewpoint of the discharge and molding workability, preferably 45,000% by mass or less, more preferably 30,000% by mass or less, still more preferably 24,000% by mass or less, even more preferably 20,000% by mass or less, from the viewpoints of suppressing the generation of slime and shape change of the hydraulic composition and the strength development property.

[0049] The additive for the hydraulic composition of the present invention may optionally contain one or more of a dispersant, an antifoaming agent, a preservative, an early strength component of the hydraulic composition, a hardening accelerator, a hardening retarder, an AE agent, a waterproof agent, a shrinkage reducing agent, a rust preventive agent, a crack reducing agent, a pH adjuster, a thickener, a separation reducing agent, a dust reducing agent, a slime inhibitor, an anti-sagging agent, and other surfactants.

[0050] The additive for the hydraulic composition of the present invention is an additive for a hydraulic composition, and may be, for example, an additive for a hydraulic composition for spraying, plastering, vibration-molded products, centrifugally molded products, concrete structures, or 3D printers. The additive for the hydraulic composition of the present invention is preferably an additive composition for a sprayed hydraulic composition from the viewpoint of suppressing the generation of slime and shape change of the hydraulic composition.

[0051] <Hydraulic composition> The present invention provides a hydraulic composition containing (A) carboxymethyl cellulose or a salt thereof [component (A)], (B) a halide [component (B)], hydraulic powder, and water. Further, the hydraulic composition of the present invention can optionally contain (C) a flash setting agent [component (C)]. Further, the hydraulic composition of the present invention may be a hydraulic composition containing the additive for the hydraulic composition of the present invention, hydraulic powder, and water. In the hydraulic composition of the present invention, the preferred embodiments of component (A), component (B), component (C), and the additive for the hydraulic composition of the present invention are the same as the preferred embodiments of component (A), component (B), component (C), and the additive for the hydraulic composition of the present invention described in the above additive for the hydraulic composition of the present invention.

[0052] <Hydraulic powder> The hydraulic powder used in the hydraulic composition of the present invention is a powder that hardens when mixed with water. Examples include ordinary Portland cement, early strength Portland cement, ultra-early strength Portland cement, sulfate-resistant Portland cement, low heat Portland cement, medium heat Portland cement, white Portland cement, alumina cement, and eco-cement (e.g., JIS R 5214, etc.). Among these, from the perspective of the spread of the sprayed hydraulic composition, cement selected from early strength Portland cement, ordinary Portland cement, sulfate-resistant Portland cement, and white Portland cement is preferred, and early strength Portland cement and ordinary Portland cement are more preferred.

[0053] In addition, the hydraulic powder may contain blast furnace slag, fly ash, silica fume, anhydrous gypsum, etc., and may also contain non-hydraulic fine limestone powder, etc. As the hydraulic powder, blast furnace cement, fly ash cement, or silica fume cement in which cement is mixed with blast furnace slag, fly ash, silica fume, etc. may be used.

[0054] <Water> The hydraulic composition of the present invention contains water. Examples of the water include tap water, groundwater, lake water, and river water.

[0055] <Composition, etc.> The hydraulic composition of the present invention contains the component (A) in an amount of preferably 0.005% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.02% by mass or more, and most preferably 0.03% by mass or more, based on the hydraulic powder in the hydraulic composition, from the viewpoint of suppressing the generation of slime and shape change of the hydraulic composition. From the viewpoint of discharge and molding workability, it preferably contains 5% by mass or less, more preferably 3% by mass or less, still more preferably 1.5% by mass or less, and most preferably 1% by mass or less. That is, in the hydraulic composition of the present invention, the ratio [(A) / (hydraulic powder)] of the content of the component (A) to the content of the hydraulic powder is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.02% by mass or more, and most preferably 0.03% by mass or more, from the viewpoint of suppressing the generation of slime and shape change of the hydraulic composition. From the viewpoint of discharge and molding workability, it is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1.5% by mass or less, and most preferably 1% by mass or less.

[0056] The hydraulic composition of the present invention contains the component (B) in an amount of preferably 0.000025% by mass or more, more preferably 0.000035% by mass or more, still more preferably 0.00007% by mass or more, and most preferably 0.00014% by mass or more, based on the hydraulic powder in the hydraulic composition, from the viewpoint of suppressing the generation of slime and shape change of the hydraulic composition. From the same viewpoint, it preferably contains 0.002% by mass or less, more preferably 0.0015% by mass or less, and still more preferably 0.0012% by mass or less.

[0057] In the hydraulic composition of the present invention, the ratio (B) / (A) of the content of the component (B) to the content of the component (A) is 0.07% by mass or more, preferably 0.10% by mass or more, more preferably 0.12% by mass or more, and most preferably 0.15% by mass or more, from the viewpoint of suppressing the generation of slime and shape change of the hydraulic composition. From the same viewpoint, it is 3.5% by mass or less, preferably 3.0% by mass or less, more preferably 2.5% by mass or less.

[0058] The hydraulic composition of the present invention contains the additive for hydraulic composition of the present invention in an amount of preferably 0.005% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.02% by mass or more, from the viewpoint of suppressing the generation of slump and shape change of the hydraulic composition, with respect to the hydraulic powder in the hydraulic composition, and preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1.5% by mass or less, from the viewpoints of dischargeability and moldability. The preferable content range of the additive for hydraulic composition in the above hydraulic composition may be the preferable range of the preferable content of the additive for hydraulic composition not containing the component (C). When the additive for hydraulic composition of the present invention contains the component (C), the preferable content of the additive for hydraulic composition in the hydraulic composition of the present invention may be the sum of the preferable content of the above additive for hydraulic composition and the preferable content of the following component (C).

[0059] When the hydraulic composition of the present invention contains the component (C), the hydraulic composition of the present invention contains the component (C) in an amount of preferably 1% by mass or more, more preferably 4% by mass or more, still more preferably 7% by mass or more, from the viewpoints of suppressing the generation of slump and shape change of the hydraulic composition, strength developability, and dischargeability and moldability, with respect to the hydraulic powder in the hydraulic composition, and preferably 14% by mass or less, more preferably 12% by mass or less, still more preferably 10% by mass or less, from the viewpoint of suppressing the generation of slump and shape change of the hydraulic composition.

[0060] When the hydraulic composition of the present invention contains the component (C), the ratio (C) / (A) of the content of the component (C) to the content of the component (A) in the hydraulic composition of the present invention is preferably 4,000% by mass or more, more preferably 10,000% by mass or more, still more preferably 18,000% by mass or more, from the viewpoints of suppressing the generation of slump and shape change of the hydraulic composition and strength developability, and preferably 45,000% by mass or less, more preferably 30,000% by mass or less, still more preferably 24,000% by mass or less, even more preferably 20,000% by mass or less, from the viewpoint of dischargeability and moldability.

[0061] In the hydraulic composition of the present invention, the water / hydraulic powder ratio (W / C) is preferably 30% by mass or more, more preferably 35% by mass or more, still more preferably 40% by mass or more, from the viewpoints of suppressing the generation and shape change of noro in the hydraulic composition and strength development, and is preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 65% by mass or less. That is, in the hydraulic composition of the present invention, from the viewpoints of suppressing the generation and shape change of noro in the hydraulic composition and strength development, water is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, still more preferably 40 parts by mass or more, and preferably 80 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 65 parts by mass or less with respect to 100 parts by mass of the hydraulic powder contained in the hydraulic composition. Note that this water / hydraulic powder ratio (W / C) represents the ratio of water to the hydraulic powder in the hydraulic composition as a mass percentage (mass%), and is calculated by (water / hydraulic powder) × 100. Further, when the hydraulic powder includes powders having properties that harden by a hydration reaction such as cement, as well as powders having a pozzolanic action, latent hydraulicity, and stone powder (calcium carbonate powder), in the present invention, the amounts of these are also included in the amount of the hydraulic powder. However, when these components are included in the (C) quick-setting agent, the components included in the (C) quick-setting agent are not included in the amount of the hydraulic powder. Also, when the powder having properties that harden by a hydration reaction contains a high-strength admixture, the amount of the high-strength admixture is also included in the amount of the hydraulic powder. This is the same for other parts by mass related to the mass of the hydraulic powder.

[0062] <Aggregate> The hydraulic composition of the present invention can optionally contain an aggregate. Examples of the aggregate include aggregates selected from fine aggregates and coarse aggregates. Examples of the fine aggregate include those defined by No. 2311 in JIS A 0203-2014. Examples of the fine aggregate include river sand, land sand, mountain sand, sea sand, lime sand, silica sand, and crushed sand thereof, blast furnace slag fine aggregate, ferronickel slag fine aggregate, lightweight fine aggregate (artificial and natural), and recycled fine aggregate. In addition, examples of the coarse aggregate include those defined by No. 2312 in JIS A 0203-2014. For example, the coarse aggregate includes river gravel, land gravel, mountain gravel, sea gravel, lime gravel, crushed stones thereof, blast furnace slag coarse aggregate, ferronickel slag coarse aggregate, lightweight coarse aggregate (artificial and natural), recycled coarse aggregate, and the like. The fine aggregate and the coarse aggregate may be used by mixing those of different types, or a single type may be used. The hydraulic composition of the present invention can contain fine aggregate as an aggregate. The amount of the fine aggregate used in the hydraulic composition of the present invention is preferably 500 kg / m 3 or more, more preferably 600 kg / m 3 or more, and preferably 2,000 kg / m 3 or less, more preferably 1,700 kg / m 3 or less. In the hydraulic composition of the present invention, the fine aggregate ratio is preferably 35% or more, more preferably 45% or more, and preferably 100% or less, more preferably 70% or less, and still more preferably 65% or less. Here, the fine aggregate ratio is the volume content ratio of the fine aggregate in all the aggregates.

[0063] <(D) component> The hydraulic composition of the present invention can optionally contain (D) clay mineral [hereinafter referred to as (D) component]. (D) The clay minerals include cation-exchangeable layered silicates. Examples of such clay minerals include one or more clay minerals selected from smectite and bentonite. Smectite is a group of cation-exchangeable layered silicates belonging to clay minerals. As natural products, in addition to montmorillonite, which is well-known as the main component of bentonite, beidellite, hectorite, saponite, nontronite, etc. can be mentioned, and as synthetic products, swelling fluorine mica etc. can be mentioned. Among these, as the clay mineral contained in the hydraulic composition of the present invention, from the viewpoint of suppressing the generation and shape change of noro in the hydraulic composition, clay minerals selected from bentonite, saponite, hectorite, and montmorillonite are preferable, clay minerals selected from bentonite and montmorillonite are more preferable, and bentonite is even more preferable. The content of the clay mineral selected from bentonite, saponite, hectorite, and montmorillonite is preferably 60% by mass or more, more preferably 100% by mass, and even more preferably 100% by mass of the clay minerals contained in the hydraulic composition.

[0064] (D) The clay mineral is preferably a clay mineral having a swelling degree of preferably 10 mL / 2 g or more, more preferably 20 mL / 2 g or more, and preferably 50 mL / 2 g or less, more preferably 45 mL / 2 g or less, and even more preferably 40 mL / 2 g or less, from the viewpoint of suppressing the generation and shape change of noro in the hydraulic composition. This swelling degree is measured according to the swelling test method for bentonite (powder form) of JBAS104:77 of the Japan Bentonite Industry Association. That is, 2.0 g of a sample adjusted to 8.0% by mass of moisture is added in about 10 portions to a 100 mL stoppered graduated cylinder containing 100 mL of distilled water. At this time, the next addition is made after the previous additive has deposited on the bottom of the graduated cylinder. When left for 24 hours, the apparent volume of the sample mass at the bottom of the graduated cylinder that has swelled is read from the scale of the graduated cylinder and expressed as the swelling degree (mL / 2 g).

[0065] When the hydraulic composition of the present invention contains the component (D), the hydraulic composition of the present invention contains the component (D) in an amount of preferably 0.03% by mass or more, more preferably 0.04% by mass or more, still more preferably 0.05% by mass or more, and preferably 7% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less, based on the hydraulic powder in the hydraulic composition, from the viewpoint of preventing the generation and shape change of slump of the hydraulic composition.

[0066] The hydraulic composition of the present invention may optionally contain one or more of a dispersant, a high-performance water reducer, a high-performance AE water reducer, an AE water reducer and a water reducer containing a fluidizing agent, an expansive agent, a hardening accelerator, a hardening retarder, a polymer for cement, a foaming agent, a waterproof agent, a rust preventive agent, a shrinkage reducing agent, a pigment, a fiber, a water repellent, a white efflorescence preventive agent, a thickening agent, etc. (however, excluding those corresponding to the component (A)).

[0067] The hydraulic composition of the present invention may be a hydraulic composition for spraying, plastering, vibration-molded products, centrifugally-molded products, concrete structures, or 3D printers, and is preferably a hydraulic composition for spraying from the viewpoints of suppressing the generation and shape change of slump of the hydraulic composition and workability.

[0068] When the hydraulic composition of the present invention is used as a hydraulic composition for spraying, the target surface to be sprayed with the hydraulic composition of the present invention includes tunnels such as roads, railways, and water conduits, slopes formed by excavation of natural ground, embankments, underground spaces, and concrete structures to be repaired by the spraying method.

[0069] <Method for producing an additive for hydraulic composition> The present invention provides a method for producing an additive for a hydraulic composition, which comprises mixing the component (A) and the component (B). In the method for producing an additive for a hydraulic composition of the present invention, an accelerating agent (component (C)) can be optionally mixed. In the method for producing an additive for a hydraulic composition of the present invention, the preferred embodiments of component (A), component (B), and component (C) are the same as the preferred embodiments of the respective components described in the additive for a hydraulic composition of the present invention above. Further, in producing the additive for a hydraulic composition of the present invention, optional components described in the additive for a hydraulic composition can be mixed. The preferred mixing amounts of these components can be applied by reading the preferred contents of the respective components in the additive for a hydraulic composition as mixing amounts. Also, specific examples of the method for producing the additive for a hydraulic composition of the present invention will be described in the spraying method of the present invention, which will be described in detail later. However, the method for producing the additive for a hydraulic composition of the present invention is not limited to the specifically described embodiments.

[0070] <Method for producing a hydraulic composition> The present invention provides a method for producing a hydraulic composition, which comprises mixing component (A), component (B), hydraulic powder, and water. The method for producing a hydraulic composition of the present invention may be a method for producing a hydraulic composition, which comprises mixing the additive for a hydraulic composition of the present invention, hydraulic powder, and water. In the method for producing a hydraulic composition of the present invention, (C) a flash setting agent [(C) component] can be optionally mixed. In the method for producing a hydraulic composition of the present invention, the preferred embodiments of component (A), component (B), component (C), the additive for a hydraulic composition, hydraulic powder, and water are the same as the preferred embodiments of the respective components described in the additive for a hydraulic composition of the present invention or the hydraulic composition of the present invention above. Further, in producing the hydraulic composition of the present invention, optional components described in the hydraulic composition can be mixed. The preferred mixing amounts of these components can be applied by reading the preferred contents of the respective components in the sprayed hydraulic composition as mixing amounts. Also, specific examples of the method for producing a hydraulic composition of the present invention will be described in the spraying method of the present invention, which will be described in detail later. However, the method for producing a hydraulic composition of the present invention is not limited to the specifically described embodiments.

[0071] <Spraying method> The present invention provides a spraying method for spraying the hydraulic composition of the present invention onto a target surface. In the spraying method of the present invention, a (C) quick-setting agent may be mixed into the hydraulic composition obtained by mixing the (A) component, the (B) component, the hydraulic powder, and water, and the sprayed hydraulic composition mixed with the (C) quick-setting agent may be sprayed onto an object. In the spraying method of the present invention, a (C) quick-setting agent may be optionally mixed into the hydraulic composition obtained by mixing the additive for the hydraulic composition of the present invention, the hydraulic powder, and water, and the sprayed hydraulic composition optionally mixed with the (C) quick-setting agent may be sprayed onto an object.

[0072] In the spraying method of the present invention, the preferred embodiments of the (A) component, the (B) component, the (C) component, the additive for the hydraulic composition, the hydraulic powder, water, the hydraulic composition, and other optional components are the same as those described in the additive for the hydraulic composition of the present invention or the hydraulic composition of the present invention. Also, the target surface onto which the hydraulic composition is sprayed in the spraying step of the present invention is the same as the target surface described in the hydraulic composition of the present invention. The spraying method of the present invention can apply the embodiments described in the hydraulic composition of the present invention. The preferred content of each component in the hydraulic composition of the present invention can be replaced with the preferred mixing amount of each component and applied to the spraying method of the present invention.

[0073] The spraying method of the present invention preferably includes a method in which the hydraulic composition of the present invention and the (C) accelerator are separately pressure-fed and then joined and mixed, or a method in which an accelerator slurry obtained by adding water to the powder accelerator to form a slurry before joining and mixing is joined and mixed with the hydraulic composition and then sprayed. Either a dry spraying method or a wet spraying method can be used. Examples of the dry spraying method include a method in which a hydraulic powder and an aggregate are mixed, pneumatically fed, and water and the (C) accelerator are joined and mixed and then sprayed in a wet state. Examples of the wet spraying method include a method in which a hydraulic powder, an aggregate, and water are mixed and kneaded, pneumatically fed, and the (C) accelerator is joined and mixed and then sprayed. The (A) component, the (B) component, and further the additive for the hydraulic composition of the present invention can be mixed with, for example, the (C) component and then mixed into the hydraulic composition containing the hydraulic powder and water, but can also be added to water in advance and then mixed into the hydraulic composition.

[0074] Specific examples will be given to explain the spraying method of the present invention in detail. Note that the spraying method of the present invention is not limited to this specific example. In the spraying method of the present invention, first, the (A) component and the (B) component are mixed to produce an additive for the hydraulic composition. Then, this additive for the hydraulic composition, the hydraulic powder, and water are mixed to produce a hydraulic composition. The water / hydraulic powder ratio (W / C) [mass percentage (mass%) of water and hydraulic powder in the hydraulic composition] of this hydraulic composition is preferably 30% by mass or more, more preferably 35% by mass or more, still more preferably 40% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 65% by mass or less, from the viewpoint of suppressing the generation and shape change of the noro of the hydraulic composition.

[0075] In the present invention, for the mixing of component (A) and component (B), mixing mixers such as a pan-type forced mixer, a twin-screw forced mixer, a tilting mixer, a Hobart mixer, a rotary mixer, a W-type mixer, a V-type mixer, a drum-type mixer, a conical screw-type mixer, a ribbon mixer, a tumbler mixer, a double-cone mixer, a mill mixer, a juicer mixer, a hand mixer, etc. can be used. Further, the mixing of the additive for the hydraulic composition, the hydraulic powder, water and other optional components can be carried out by a known method. For example, there is a method of simultaneously mixing the additive for the hydraulic composition, the hydraulic powder and water using a mixing mixer such as a pan-type forced mixer, a twin-screw forced mixer, a tilting mixer, etc.

[0076] In the present invention, to the hydraulic composition obtained by mixing component (A), component (B), the hydraulic powder and water, (C) a quick-setting agent and / or (D) a clay mineral can be optionally added to produce a sprayed hydraulic composition. The mixing of the hydraulic composition and (C) the quick-setting agent and / or (D) the clay mineral can be carried out, for example, by a general spraying method in which the hydraulic composition and (C) the quick-setting agent and / or (D) the clay mineral are pneumatically conveyed and joined for mixing.

[0077] In the spraying method of the present invention, the thus-prepared sprayed hydraulic composition is sprayed onto an object. The spraying method of the present invention can be carried out by conventional spraying equipment. The spraying equipment only needs to be able to perform spraying without trouble. For example, for the pressure feeding of the hydraulic composition, "Ariba 280" etc. manufactured by Ariba Co., Ltd. are used, and for the pressure feeding of (C) the quick-setting agent and / or (D) the clay mineral, "Natomcrete" etc. manufactured by Chiyoda Manufacturing Co., Ltd. are used, and it is possible to mix both to prepare a sprayed hydraulic composition and perform spraying.

Examples

[0078] In the examples and comparative examples, a hydraulic composition was produced with the formulations shown in Table 1. Further, in the examples and comparative examples, the following component (A), component (B) and component (C) were used.

[0079]

Table 1

[0080] The components in Table 1 are as follows. W: Tap water C: Hydraulic powder, ordinary Portland cement (two-component mixture: Taiheiyo Cement / Sumitomo Osaka Cement = 1 / 1, mass ratio), density 3.16 g / cm 3 S: Fine aggregate (S): Sand from Chengyang, density 2.55 g / cm 3

[0081] <Component (A)> · A-1: Sodium carboxymethyl cellulose salt, degree of etherification 0.7, average particle diameter 116 μm, weight average molecular weight 560,000, viscosity of 1 mass% aqueous solution (25 °C) 45 mPa·s, CMC Daicel 1130, manufactured by Daicel Miraiz Co., Ltd. · A-2: Sodium carboxymethyl cellulose salt, degree of etherification 0.68, average particle diameter 89 μm, weight average molecular weight 1,096,000, viscosity of 1 mass% aqueous solution (25 °C) 200 mPa·s, CMC Daicel 1160, manufactured by Daicel Miraiz Co., Ltd. · A-3: Sodium carboxymethyl cellulose salt, degree of etherification 0.87, average particle diameter 65 μm, weight average molecular weight 4,023,000, viscosity of 1 mass% (25 °C) 4400 mPa·s, CMC Daicel FH 4000A, manufactured by Daicel Miraiz Co., Ltd. · A-4: Sodium carboxymethyl cellulose salt, degree of etherification 0.74, average particle diameter 90 μm, weight average molecular weight 364,000, viscosity of 1 mass% aqueous solution (25 °C) 20 mPa·s, CMC Daicel 1110, manufactured by Daicel Miraiz Co., Ltd. · A-5: Sodium carboxymethyl cellulose salt, degree of etherification 1.27, average particle diameter 44 μm, weight average molecular weight 753,000, viscosity of 1 mass% aqueous solution (25 °C) 45 mPa·s, CMC Daicel 1330, manufactured by Daicel Miraiz Co., Ltd. Note that the degree of etherification, average particle diameter, weight average molecular weight, and viscosity of 1 mass% aqueous solution of component (A) were measured by the methods described in the detailed description of the above component (A).

[0082] <(B) Component: Halide> ·B-1: Sodium chloride, manufactured by FUJIFILM Wako Pure Chemical Corporation ·B-2: Potassium chloride, manufactured by FUJIFILM Wako Pure Chemical Corporation ·B-3: Ammonium chloride, manufactured by FUJIFILM Wako Pure Chemical Corporation ·B-4: Calcium chloride, manufactured by FUJIFILM Wako Pure Chemical Corporation <(C) Component: Accelerator> ·C-1: Calcium aluminate-based accelerator: A powdered accelerator mainly composed of calcium aluminate

[0083] (1) Preparation of Hydraulic Composition (Mortar) To a Hobart mixer (manufactured by Kansai Kiki Seisakusho Co., Ltd., KC-8), ordinary cement (C), which is a hydraulic powder, and sand (S) were added according to the formulation shown in Table 1, and dry mixing was carried out for 10 seconds. Water (W) was added to the mixture of dry-mixed cement (C) and sand (S), and stirring was performed at a low speed for 2 minutes (stirring speed: revolution 62 rpm, rotation 141 rpm) to prepare mortar. The additive for hydraulic composition shown in Table 2 was added to the obtained mortar, and stirring was carried out by hand for 5 seconds to obtain a hydraulic composition. The additive for hydraulic composition contains the (A) component and the (B) component [and the (C) accelerator as required] in the proportions shown in the table. When the (A) component, the (B) component, and the (C) component are included, the amount of the (C) component was added so as to be the amount shown in the table. Also, when manufacturing the hydraulic composition shown in Table 3, after preparing mortar with the formulation shown in Table 1 in the same manner as above, the additive for hydraulic composition shown in Table 3 was added to the obtained mortar, and stirring was carried out at a high speed for 10 seconds (stirring speed: revolution 125 rpm, rotation 285 rpm) to obtain a hydraulic composition.

[0084] (2) Evaluation (2-1) Evaluation of Norovirus Generation Rate 1,500 g of the hydraulic composition obtained in (1) was sprayed onto a wooden board 18 cm away from the injection port of a powder and granular material conveying device (Bress Rider, model number K-40, manufactured by Bress Co., Ltd.) using the powder and granular material conveying device. The pressure of the compressor connected to the powder and granular material conveying device was 0.6 MPa, and the diameter φ of the injection port was 3.5 cm. Those without norovirus adhered and accumulated only at the spraying location, but for those with norovirus, it was confirmed that the paste component of the mortar and a small amount of fine aggregate flowed down just below the spraying location. The mass of the hydraulic composition that fell below the wooden board and the mass of the hydraulic composition that adhered 8 cm below the wooden board were measured, and the norovirus generation rate (mass %) was calculated from the following formula (1). The results are shown in Table 2. The lower this norovirus generation rate, the more it can be said that the generation of norovirus is suppressed when the hydraulic composition is sprayed onto the target surface. Norovirus generation rate (mass %) = 100 × [(mass of the hydraulic composition that fell below the wooden board) + (mass of the hydraulic composition that adhered 8 cm below the wooden board)] / (total mass of the sprayed hydraulic composition) (1)

[0085] (2-2) Evaluation of shape retention In accordance with JIS R 5201, the hydraulic composition prepared in (1) was filled into a flow cone (upper diameter 70 mm × lower diameter 100 mm × height 60 mm), pulled up vertically on a flow table, and the spread after 1 minute was measured as the initial mortar flow. The results are shown in Table 3. From the perspective of ensuring shape retention, a smaller initial mortar flow is preferable.

[0086]

Table 2

[0087]

Table 3

Claims

1. An additive for a hydraulic composition, comprising (A) carboxymethyl cellulose or a salt thereof [hereinafter referred to as component (A)], and (B) a halide [hereinafter referred to as component (B)], wherein the ratio (B) / (A) of the content of component (B) to the content of component (A) is 0.07% by mass or more and 3.5% by mass or less.

2. The additive for a hydraulic composition according to claim 1, wherein component (A) is in powder form and the average particle diameter of component (A) is 0.5 μm or more and 500 μm or less.

3. The additive for a hydraulic composition according to claim 1 or 2, wherein the degree of etherification of component (A) is 0.5 or more and 1.5 or less.

4. The additive for a hydraulic composition according to any one of claims 1 to 3, further comprising (C) a flash setting agent [hereinafter referred to as component (C)].

5. A hydraulic composition, comprising (A) carboxymethyl cellulose or a salt thereof [hereinafter referred to as component (A)], (B) a halide [hereinafter referred to as component (B)], hydraulic powder, and water, wherein the ratio (B) / (A) of the content of component (B) to the content of component (A) is 0.07% by mass or more and 3.5% by mass or less.

6. The hydraulic composition according to claim 5, wherein the ratio [(A) / (hydraulic powder)] of the content of component (A) to the content of the hydraulic powder is 0.01% by mass or more and 1% by mass or less.

7. The hydraulic composition according to claim 5 or 6, which is for spraying.

8. A method for producing a hydraulic composition, comprising mixing (A) carboxymethyl cellulose or a salt thereof [hereinafter referred to as component (A)], (B) a halide [hereinafter referred to as component (B)], hydraulic powder, and water so that the ratio (B) / (A) of the mixing amount of component (B) to the mixing amount of component (A) is 0.07% by mass or more and 3.5% by mass or less.

9. A spraying method of spraying the hydraulic composition according to any one of claims 5 to 7 onto a target surface.

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