Premix for hydraulic composition

Abstract

To provide a premix for a hydraulic composition which is less likely to cause the setting dalay of the hydraulic composition when a fine aggregate and a dispersant are used together and a method for producing the same, a method for producing a hydraulic composition using the premix for a hydraulic composition and a dry spraying method using the premix for a hydraulic composition.SOLUTION: There is provided a premix for a hydraulic composition which comprises (A) cement, (B) a fine aggregate having a surface water ratio of -5% or more and less than 0%, (C) a polycarboxylic acid-based dispersant and (D) a polyalkylene oxide having a weight average molecular weight of 5000 or more and less than 1000000.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a premix for a hydraulic composition and a method for producing the same, a method for producing a hydraulic composition using the premix for a hydraulic composition, and a dry spraying method using the premix for a hydraulic composition. [Background technology]

[0002] Concrete is an essential construction material for the development of mankind, and cement concrete in particular is produced by mixing cement, water, fine aggregate, and coarse aggregate, forming the mixture, and then hardening it. Examples of fine aggregates include natural aggregates such as river sand, land sand, mountain sand, sea sand, lime sand, and silica sand, which are defined by number 2311 in JIS A0203-2014, and artificial aggregates such as crushed sands of these, blast furnace slag fine aggregate, ferronickel slag fine aggregate, lightweight fine aggregate, and recycled fine aggregate. Most fine aggregates are inorganic materials composed primarily of silica, which are produced as a result of volcanic activity or industrial by-products. They are exposed to high temperatures during their production, and as a result of the evaporation of water of hydration, dehydration, and the burning of organic matter, they are porous.

[0003] For this reason, even in the concrete industry, fine aggregate is often used in a state in which it contains air or water vapor inside. However, it is known that when fine aggregate used in a premix for hydraulic compositions, which is characterized by being able to prepare a hydraulic composition on-site by adding only water and kneading, comes into contact with hydraulic powder in a state in which water has bled onto the surface, the hydraulic powder undergoes a hydration reaction and becomes "weathered" during storage, and the hydration reactivity due to the addition of water and kneading decreases, resulting in a decrease in strength, which is one of the main properties required of concrete. Therefore, for the premix for hydraulic composition, fine aggregate in an absolutely dry state or in an air-dried state is used, which has no water bleeding onto the surface and has a negative surface water ratio calculated according to the method specified in JIS A 1111.

[0004] Also, spraying methods using hydraulic compositions are used to prevent the collapse of exposed natural ground during tunnel construction, slope protection construction, etc. Among these methods, the dry spraying method is a method in which a premix for hydraulic compositions containing cement, fine aggregate, etc. is put into a spraying machine, and then compressed air is used to pump it through a hose, where it is combined with water pumped from a separate system at the spray nozzle at the tip, and this combined mixture (hydraulic composition) is sprayed from the tip of the spray nozzle onto the natural ground surface until a specified thickness is achieved.

[0005] Patent Document 1 discloses a premix mortar composition and a premix non-shrink mortar composition that use a polycarboxylate-based water-reducing agent and that can suppress a decrease in fluidity and a decrease in fluidity retention even when the premix mortar composition and the premix non-shrink mortar composition are stored for a long period of time by blending calcium carbonate powder into the premix mortar composition. Patent Document 2 discloses a non-shrink mortar composition which is prepared by blending cement, an expanding agent, an additive, a foaming agent, and a fine aggregate, and in which, per 100 parts in total, the foaming agent of a specific particle size is 0.001 to 0.01 parts of metallic aluminums, and a non-shrink mortar composition or a fast-hardening non-shrink mortar composition which is prepared by blending calcium aluminate and a sulfate, and in which, per 100 parts in total, the additive is 0.001 to 1.0 parts of an alkali metal carbonate, and the foaming agent is 0.001 to 0.01 parts of metallic aluminums, and which maintains the quality immediately after production even after long-term storage, with little deterioration in quality, in particular, little decrease in initial expansion rate, and good fluidity, thereby preventing settlement and cracking due to shrinkage, and which provides excellent quality. Patent Document 3 discloses an admixture for hydraulic compositions that can provide excellent initial fluidity and fluidity retention to hydraulic compositions containing hydraulic powder, the admixture comprising (A) one or more copolymers selected from the group consisting of a specific binary copolymer (A-1) and a specific phosphate ester copolymer (A-2), (B) a specific ternary copolymer, and (C) a polyethylene glycol having a weight-average molecular weight of 1,000 to 90,000. Patent Document 4 discloses a spraying method in which a liquid quick-setting admixture containing 100 parts of aluminum sulfate and less than 2 parts of bisphenol S is mixed with cement concrete containing a polyalkylene oxide having an average molecular weight of 1 to 5 million. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2011-241095 A [Patent Document 2] JP 2001-328856 A [Patent Document 3] JP 2009-249197 A [Patent Document 4] JP 2014-5184 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, a premix for a hydraulic composition, which is used for a hydraulic composition under conditions of a low mass ratio of water to cement, contains a powdery dispersant to impart fluidity to the hydraulic composition, but the use of a dispersant in combination slows down the hardening of the hydraulic composition, i.e., causes a problem of delayed setting.

[0008] The present invention provides a premix for a hydraulic composition which is less likely to cause delay in setting of the hydraulic composition when fine aggregate and a dispersant are used in combination, a method for producing the same, a method for producing a hydraulic composition using the premix for a hydraulic composition, and a dry spraying method using the premix for a hydraulic composition. [Means for solving the problem]

[0009] The present invention relates to a premix for a hydraulic composition, which contains (A) cement (hereinafter referred to as component (A)), (B) fine aggregate having a surface water ratio of -5% or more and less than 0% (hereinafter referred to as component (B)), (C) a polycarboxylic acid-based dispersant (hereinafter referred to as component (C)), and (D) a polyalkylene oxide having a weight-average molecular weight of 5,000 or more and less than 1,000,000 (hereinafter referred to as component (D)).

[0010] The present invention also relates to a premix for a hydraulic composition comprising the components (A), (B), (C) and (D).

[0011] The present invention also relates to a premix for a hydraulic composition comprising component (A), fine aggregate (B') (hereinafter referred to as component (B')), component (C), and component (D), the premix for a hydraulic composition having a loss on drying of less than 2.9% by mass as measured by the following method. Loss on drying: Loss on drying (mass%) calculated by the following formula after drying the premix for hydraulic composition at 105°C for 2 hours in a constant temperature air dryer Loss on drying (mass%) = (mass of premix for hydraulic composition before drying (g) - mass of premix for hydraulic composition after drying at 105°C for 2 hours (g)) x 100 / mass of premix for hydraulic composition before drying (g)

[0012] The present invention also relates to a method for producing a premix for a hydraulic composition, which comprises mixing the (A) component, the (B) component, the (C) component, and the (D) component.

[0013] The present invention also relates to a method for producing a hydraulic composition, which comprises mixing the premix for a hydraulic composition of the present invention with water.

[0014] The present invention also relates to a dry spraying method which comprises mixing the premix for hydraulic compositions of the present invention with water to produce a hydraulic composition, and spraying the hydraulic composition onto an object. Effect of the Invention

[0015] According to the present invention, there are provided a premix for hydraulic composition which is less likely to cause delay in setting of the hydraulic composition when fine aggregate and a dispersant are used in combination, a method for producing the same, a method for producing a hydraulic composition using the premix for hydraulic composition, and a dry spraying method using the premix for hydraulic composition.

[0016] In recent years, the SDGs have been proposed to realize a sustainable society. The present invention contributes to improving the productivity of hydraulic composition hardened bodies, and is considered to be a technology that can contribute to, for example, SDGs No. 9, 11, and 12. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present inventors have discovered a premix for hydraulic compositions that is less likely to cause delay in setting of the hydraulic composition when fine aggregate and a dispersant are used in combination. The reason why such an effect is exhibited is not necessarily clear, but is presumed to be as follows. As mentioned above, the premix for hydraulic compositions is prepared by mixing hydraulic powder such as cement, dry fine aggregate, and, if necessary, coarse aggregate. When water is added to the mixture and kneaded, the hydration reaction, which is the hardening reaction of cement, and the infiltration of water into the porous fine aggregate are thought to proceed all at once. The surface of the fine aggregate is formed by hydrophilic silica, and the use of a dispersant in combination reduces the capillary pressure. Therefore, in systems in which a dispersant is used in combination, it is thought that the delay in the hydration reaction due to the adsorption of the dispersant to the cement particles and the competition for water with the fine aggregate are likely to cause a delay in the setting of the cement. Here, when the polyalkylene oxide having a specific weight average molecular weight, which is the component (D) of the present invention, is contained in a premix for hydraulic composition containing fine aggregate with a surface water ratio of less than 0% and a dispersant, it has low adsorption to cement and does not inhibit the hydration reaction of cement, and by having a molecular weight of a certain level or more, it retains water on the surface of the fine aggregate while suppressing a decrease in the surface tension of the aqueous solution, and suppresses the rapid absorption of water by the fine aggregate, and by having a molecular weight of a certain level or less, it effectively retains water without being excessively hydrophobic molecularly, and does not involve mixability due to thickening caused by significant entanglement of molecular chains and inactivation of the hydration reaction, so it is considered that even if the premix for hydraulic composition contains fine aggregate with a surface water ratio of less than 0% and a dispersant, it is less likely to cause delay in setting of cement. In addition, in the case of a premix for a hydraulic composition containing fine aggregate, a dispersant, and a polyalkylene oxide having a specific weight average molecular weight, and having a drying loss of less than 2.9 mass% measured by the above-mentioned method, it is considered that the fine aggregate contained therein is in a dry state, and is less likely to cause delay in setting of cement due to the same mechanism of action as described above. However, the present invention is not limited to the above-mentioned mechanism of action.

[0018] [Premix for hydraulic composition] <Component (A)> The premix for a hydraulic composition of the present invention contains cement as component (A). Examples of cement include ordinary Portland cement, belite cement, moderate heat cement, high-early strength cement, ultra-high-early strength cement, and sulfate-resistant cement, and may also include blast furnace slag cement, fly ash cement, and silica fume cement to which blast furnace slag, fly ash, silica fume, stone powder (calcium carbonate powder), etc. have been added. One or more of these may be used.

[0019] The content of component (A) in the premix for hydraulic composition of the present invention is, relative to 100 parts by mass of the premix for hydraulic composition, preferably 10 parts by mass or more, more preferably 14 parts by mass or more, and even more preferably 18 parts by mass or more, from the viewpoint of strength of the set body of the hydraulic composition, and is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, still more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less, from the viewpoint of suppressing cracking of the set body of the hydraulic composition.

[0020] <(B) component> The premix for a hydraulic composition of the present invention contains, as component (B), fine aggregate having a surface water content of −5% or more and less than 0%.

[0021] The surface water content of the fine aggregate of component (B) is, from the viewpoint of the strength development and hardening acceleration of the hydraulic composition, -5% or more, preferably -4% or more, more preferably -3.5% or more, and is less than 0%, preferably -0.5% or less, more preferably -1% or less. The surface water ratio of the fine aggregate of component (B) is measured by the method described in JIS A 1111. More precisely, it is measured at 20°C by the following procedure. Place 200 mL of tap water and 500.0 g of fine aggregate into a 500 mL Chapman flask (e.g., KC-103, manufactured by Kansai Machinery Works), shake lightly, and leave to stand for 30 minutes to degas and absorb water. Record the reading on the Chapman flask (V), and calculate the surface water ratio as the average value of two tests based on the following formula. Surface water rate (%) ={(V-500.0)-(500.0 / Surface dry density of fine aggregate)} / {500.0-(V-500.0)}×100

[0022] Fine aggregate is defined as aggregate which passes entirely through a 10 mm sieve and at least 85% by weight through a 5 mm sieve. Examples of fine aggregates include those specified by number 2311 in JIS A0203-2014. Specific examples of fine aggregates include one or more types selected from 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 aggregate (artificial and natural), and recycled fine aggregate.

[0023] The surface water content of the fine aggregate of component (B) can be adjusted by the following methods: (1) selecting fine aggregate with a surface water content in a specified range, (2) subjecting the fine aggregate to a drying treatment to adjust the surface water content to the specified range, etc. The drying treatment is not particularly limited, and may be, for example, blowing air, heating, contacting with a moisture absorbent, or a combination of these treatments. A treatment including heating and drying is preferred. In addition, since the surface water ratio of fine aggregate is easily changed by the environment, after adjusting to a predetermined surface water ratio, in order to reduce the influence of external changing factors, it is preferable to maintain the surface water ratio within a predetermined range by storing in a dark place, storing sealed, controlling the temperature, etc. A more preferable method is storing in a sealed container.

[0024] The content of the component (B) in the premix for hydraulic composition of the present invention is, from the viewpoint of the strength of the set body of the hydraulic composition and hardening acceleration, preferably 40 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 60 parts by mass or more, still more preferably 70 parts by mass or more, and preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and even more preferably 80 parts by mass or less, based on 100 parts by mass of the premix for hydraulic composition.

[0025] In the premix for hydraulic composition of the present invention, the mass ratio (B) / (A) of the content of the component (A) to the content of the component (B) is preferably 0.5 or more, more preferably 0.75 or more, even more preferably 1 or more, still more preferably 2 or more, still more preferably 3 or more, from the viewpoints of suppressing cracking in the set body of the hydraulic composition and accelerating hardening, and is preferably 5 or less, more preferably 4.5 or less, even more preferably 4 or less, from the viewpoints of strength of the set body of the hydraulic composition and accelerating hardening.

[0026] <(C) component> The premix for a hydraulic composition of the present invention contains a polycarboxylic acid dispersant as component (C). From the viewpoint of strength of the cured product, the polycarboxylic acid dispersant is preferably in powder form.

[0027] Examples of polycarboxylic acid-based dispersants that can be used include copolymers of monoesters of polyalkylene glycol and (meth)acrylic acid and carboxylic acids such as (meth)acrylic acid (e.g., compounds described in JP-A-8-12397), copolymers of unsaturated alcohols having polyalkylene glycol and carboxylic acids such as (meth)acrylic acid, and copolymers of unsaturated alcohols having polyalkylene glycol and dicarboxylic acids such as maleic acid. Here, (meth)acrylic acid means a carboxylic acid selected from acrylic acid and methacrylic acid.

[0028] The polycarboxylic acid polymer may be a copolymer (c) containing, as constituent monomers, a monomer (1c) represented by the following general formula (1c) and a monomer (2c) represented by the following general formula (2c).

[0029] [ka]

[0030] [During the ceremony, R 1c , R 2c , R 3c may be the same or different, and may be a hydrogen atom, a methyl group or (CH2) r COOM 2 and (CH2) r COOM 2 COOM 1 or other (CH2) r COOM 2 and an anhydride may be formed, in which case, M 1 , M 2 does not exist. M 1 , M2 may be the same or different, and are a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2 atom), an ammonium group, an alkylammonium group, a substituted alkylammonium group, an alkyl group, a hydroalkyl group, or an alkenyl group. r: A number between 0 and 2 Indicates the following.

[0031] [ka]

[0032] [During the ceremony, R 4c , R 5c : may be the same or different, hydrogen atom or methyl group R 6c : Hydrogen atom or -(CH2) q1 (CO) p1 O(AO) n1 R 7c R 7c : Hydrogen atom or an alkyl group having 1 to 4 carbon atoms AO: an alkyleneoxy group having 2 to 4 carbon atoms n1: the average number of moles of AO added, a number between 4 and 200 q1: A number between 0 and 2 p1: 0 or 1 Indicates the following.

[0033] In the general formula (1c), R 1c is preferably a hydrogen atom. In the general formula (1c), R 2c is preferably a hydrogen atom or a methyl group. In the general formula (1c), R 3c is preferably a hydrogen atom. (CH2) r COOM 2 About COOM 1 or other (CH2) r COOM 2 and an acid anhydride may be formed, in which case, M 1 , M2 does not exist. M 1 and M. 2 may be the same or different and are a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2 atom), an ammonium group, an alkylammonium group, a substituted alkylammonium group, an alkyl group, a hydroalkyl group, or an alkenyl group. M 1 and M. 2 The alkyl group, the hydroalkyl group, and the alkenyl group each preferably have 1 to 4 carbon atoms. M 1 and M. 2 may be the same or different and are preferably a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2 atom), an ammonium group, or an alkylammonium group, more preferably a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2 atom), or an ammonium group, even more preferably a hydrogen atom, an alkali metal, or an alkaline earth metal (1 / 2 atom), and even more preferably a hydrogen atom or an alkali metal. (CH2) in general formula (1c) r COOM 2 In the formula, r is preferably 0.

[0034] In general formula (2c), R 4c is preferably a hydrogen atom from the viewpoint of availability. In general formula (2c), R 5c From the viewpoint of availability, is preferably a hydrogen atom or a methyl group, and more preferably a methyl group. In general formula (2c), R 6c is preferably a hydrogen atom from the viewpoint of availability. In general formula (2c), R 7c From the viewpoint of availability, is preferably a hydrogen atom or a methyl group, and more preferably a methyl group. In the general formula (2c), AO is preferably a group selected from an ethyleneoxy group and a propyleneoxy group, more preferably an ethyleneoxy group. AO preferably contains an ethyleneoxy group. In formula (2c), n1 is the average number of moles of AO added, and is preferably 4 or more, more preferably 20 or more, and is preferably 150 or less, more preferably 120 or less. In formula (2c), q1 is preferably 0, 1 or 2, more preferably 0 or 1, and even more preferably 0. In formula (2c), p1 is preferably 1.

[0035] The proportion of monomer (1c) in the total amount of monomer (1c) and monomer (2c) in all constituent monomers of copolymer (c) is preferably 1 mass% or more, more preferably 5 mass% or more, even more preferably 10 mass% or more, and preferably 40 mass% or less, more preferably 30 mass% or less, even more preferably 20 mass% or less.

[0036] The proportion of monomer (1c) in all constituent monomers of copolymer (c) is preferably 1 mass% or more, more preferably 5 mass% or more, even more preferably 10 mass% or more, and preferably 40 mass% or less, more preferably 30 mass% or less, even more preferably 20 mass% or less.

[0037] In the total constituent monomers of the copolymer (c), the total amount of the monomer (1c) and the monomer (2c) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and preferably 100% by mass or less. This total amount may be 100% by mass.

[0038] The weight average molecular weight of the copolymer (c) is preferably 5,000 or more, more preferably 10,000 or more, even more preferably 20,000 or more, and preferably 10,0000 or less, more preferably 80,000 or less, even more preferably 60,000 or less.

[0039] The weight average molecular weight of the copolymer (c) was measured by gel permeation chromatography (GPC) under the following conditions. *GPC conditions Equipment: 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: 0.2mg / mL Standard substance: Polyethylene glycol equivalent (monodisperse polyethylene glycol with known molecular weight, molecular weight 87,500, 250,000, 145,000, 46,000, 24,000)

[0040] In addition to the monomer (1c) and the monomer (2c), the copolymer (c) may optionally contain one or more monomers (3c) copolymerizable with the monomer (1c) and / or the monomer (2c). Examples of the monomer (3c) include acrylic acid esters. In the copolymer (c), the total of the monomer (1c) and the monomer (2c), or the total of the monomer (1c), the monomer (2c), and the monomer (3c) may be 100% by mass in all the structural units.

[0041] The content of component (C) in the premix for hydraulic composition of the present invention is, relative to 100 parts by mass of the premix for hydraulic composition, preferably 0.001 part by mass or more, more preferably 0.005 part by mass or more, and even more preferably 0.01 part by mass or more, from the viewpoint of the workability of the hydraulic composition, and is preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, even more preferably 0.1 part by mass or less, and even more preferably 0.05 part by mass or less, from the viewpoint of the strength of the set body of the hydraulic composition.

[0042] The content of the (C) component in the premix for hydraulic composition of the present invention is, relative to 100 parts by mass of the (A) component, 0.05 parts by mass or more, preferably 0.075 parts by mass or more, and more preferably 0.1 parts by mass or more from the viewpoint of the workability of the hydraulic composition, and 1 part by mass or less, preferably 0.75 parts by mass or less, more preferably 0.5 parts by mass or less, and even more preferably 0.2 parts by mass or less from the viewpoint of the strength of the set body of the hydraulic composition.

[0043] <(D) component> The premix for a hydraulic composition of the present invention contains, as component (D), a polyalkylene oxide having a weight average molecular weight of 5,000 or more and less than 1,000,000.

[0044] The weight average molecular weight of the (D) component is, from the viewpoint of hardening acceleration of the hydraulic composition, 5,000 or more, preferably 10,000 or more, more preferably 50,000 or more, even more preferably 100,000 or more, still more preferably 150,000 or more, still more preferably 200,000 or more, still more preferably 250,000 or more, still more preferably 300,000 or more, still more preferably 350,000 or more, still more preferably 400,000 or more, and from the viewpoints of hardening acceleration of the hydraulic composition and workability of the hydraulic composition, it is less than 1,000,000, preferably 900,000 or less, more preferably 800,000 or less, still more preferably 700,000 or less, still more preferably 600,000 or less, still more preferably 500,000 or less. In the case of commercially available products, the weight average molecular weight of the polyalkylene oxide may be a value based on the product information (catalog, etc.). The weight average molecular weight of the polyalkylene oxide can be determined by gel permeation chromatography (GPC) under the following measurement conditions. Measurement conditions: Equipment: Product name "LC-10AD" (manufactured by Shimadzu Corporation) Detector: Refractive index detector (RID) Column: Product name "SHODEX KF-804" (manufactured by Showa Denko K.K.) ·Measurement temperature: 30℃ ·Eluent:THF ·Flow rate: 1.0mL / min Sample concentration: 0.2% by mass (THF) Sample injection volume: 100μL Conversion standard: Polyethylene oxide

[0045] The component (D) preferably contains ethylene oxide and / or propylene oxide as polymerization units, and more preferably contains ethylene oxide. When component (D) contains ethylene oxide and propylene oxide as polymerization units, the ethylene oxide and propylene oxide may be either a random copolymer or a block copolymer. From the viewpoint of water solubility, the component (D) is preferably at least one selected from a copolymer of polyoxyethylene oxide and polypropylene oxide, and polyethylene oxide, and more preferably polyethylene oxide.

[0046] The content of the (D) component in the premix for hydraulic composition of the present invention is, from the viewpoint of suppressing a decrease in the fluidity of the hydraulic composition and accelerating hardening, preferably 0.001 part by mass or more, more preferably 0.005 part by mass or more, even more preferably 0.01 part by mass or more, and preferably 1 part by mass or less, more preferably 0.5 part by mass or less, even more preferably 0.1 part by mass or less, still more preferably 0.05 part by mass or less, and even more preferably 0.03 part by mass or less, based on 100 parts by mass of the premix for hydraulic composition.

[0047] In the premix for hydraulic composition of the present invention, the content of the component (D) is, from the viewpoint of suppressing a decrease in the fluidity of the hydraulic composition and accelerating hardening, 0.05 parts by mass or more, preferably 0.075 parts by mass or more, more preferably 0.1 parts by mass or more, and 2 parts by mass or less, preferably 1 part by mass or less, preferably 0.75 parts by mass or less, more preferably 0.5 parts by mass or less, and even more preferably 0.2 parts by mass or less, per 100 parts by mass of the component (A).

[0048] <Other ingredients, etc.> The premix for a hydraulic composition of the present invention may contain coarse aggregate as component (E) within the range not impairing the effects of the present invention. Coarse aggregate is aggregate that retains 85% or more by mass on a 5 mm mesh sieve. Examples of coarse aggregate include those specified by number 2312 in JIS A0203-2014. Examples of coarse aggregate include river gravel, land gravel, mountain gravel, sea gravel, limestone gravel, crushed stones of these, blast furnace slag coarse aggregate, ferro-nickel slag coarse aggregate, lightweight coarse aggregate (artificial and natural), and recycled coarse aggregate.

[0049] When the premix for hydraulic composition of the present invention contains the component (E), the content of the component (E) is, from the viewpoint of the fluidity of the hydraulic composition, preferably 1 part by mass or more, more preferably 10 parts by mass or more, even more preferably 20 parts by mass or more, and preferably 50 parts by mass or less, more preferably 45 parts by mass or less, even more preferably 40 parts by mass or less, based on 100 parts by mass of the hydraulic composition.

[0050] The premix for hydraulic composition of the present invention may contain, as necessary, one or more selected from dispersants other than component (C), expansion agents, hardening accelerators, hardening retarders, polymers for cement, foaming agents, waterproofing agents, rust inhibitors, shrinkage reducing agents, pigments, fibers, water repellents, efflorescence inhibitors, and the like (excluding those corresponding to the above-mentioned components) within the scope not impairing the effects of the present invention.

[0051] The water content of the premix for hydraulic composition of the present invention is, from the viewpoint of accelerating the hardening of the hydraulic composition, preferably 0 part by mass or more, more preferably 0.1 part by mass or more, even more preferably 0.3 part by mass or more, still more preferably 0.5 part by mass or more, and preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less, based on 100 parts by mass of the premix for hydraulic composition. The water content is calculated based on the following formula. Moisture content of premix for hydraulic composition (parts by mass) = 100 - [(mass of premix for hydraulic composition after drying for 24 hours at 105°C x 100) / mass of premix for hydraulic composition before drying]

[0052] The premix for hydraulic composition of the present invention is most suitable for the dry spraying method, which requires the premix to contain a polycarboxylic acid-based dispersant in order to improve the mixability of water and the premix for hydraulic composition in the spraying machine, since the premix for hydraulic composition is unlikely to cause delay in setting of the hydraulic composition even when used in combination with fine aggregate (B) having a surface water ratio of less than 0% and a polycarboxylic acid-based dispersant (C). That is, the premix for a hydraulic composition of the present invention is suitable for dry spraying.

[0053] The present invention provides use of a composition containing components (A), (B), (C), and (D) as a premix for a hydraulic composition. The present invention also provides use of a composition containing components (A), (B), (C) and (D) as a premix for a hydraulic composition for dry spraying. The components (A), (B), (C), and (D), as well as the amounts and mass ratios of each component, are the same as those described in the premix for hydraulic composition of the present invention. The same also applies to other components other than the components (A) to (D), which may be contained in the composition. The amounts and mass ratios of the components can be applied to the composition by replacing the contents with the amounts of the components described in the premix for hydraulic composition of the present invention. The embodiments described in the premix for hydraulic composition of the present invention can be appropriately applied to the use of the present invention.

[0054] The present invention may be a premix for a hydraulic composition comprising the components (A), (B), (C), and (D). The components (A), (B), (C), and (D) are the same as those described in the premix for hydraulic composition of the present invention. The other components other than the components (A) to (D) are also the same and can be blended in the premix for hydraulic composition. The amounts and mass ratios of each component described in the premix for hydraulic composition of the present invention can be applied to the premix for hydraulic composition by replacing the contents with the amounts.

[0055] The premix for a hydraulic composition of the present invention has a loss on drying of less than 2.9% by mass as measured by the following method. That is, the present invention provides a premix for a hydraulic composition containing component (A), fine aggregate (B') (hereinafter referred to as component (B')), component (C), and component (D), wherein the premix for a hydraulic composition has a loss on drying of less than 2.9 mass% as measured by the following method. Loss on drying: Loss on drying (mass%) calculated by the following formula after drying the premix for hydraulic composition at 105°C for 2 hours in a constant temperature air dryer Loss on drying (mass%) = (mass of premix for hydraulic composition before drying (g) - mass of premix for hydraulic composition after drying at 105°C for 2 hours (g)) x 100 / mass of premix for hydraulic composition before drying (g) The components (A), (C), and (D) are the same as those described in the premix for hydraulic composition of the present invention. The components other than the components (A), (B'), (C), and (D) can be contained in the premix for hydraulic composition of the present invention. The content and mass ratio of each component are the same as those described in the premix for hydraulic composition of the present invention.

[0056] The loss on drying of the premix for hydraulic composition is less than 2.9% by mass, preferably 2.5% by mass or less, more preferably 2.0% by mass or less, even more preferably 1.5% by mass or less, even more preferably 1.0% by mass or less, even more preferably 0.5% by mass or less, and is 0% by mass or more, from the viewpoints of strength development and hardening acceleration of the hydraulic composition. The loss on drying is measured, for example, by weighing 10.0 g of the premix for hydraulic composition onto an aluminum flat dish, placing it in a thermostatic air-blowing dryer (e.g., DRM620DE, manufactured by Advantec Co., Ltd.), drying it at 105°C for 2 hours, and then cooling it to room temperature, measuring the mass, and calculating the loss on drying (mass%) based on the above formula.

[0057] The fine aggregate of component (B') is an aggregate which passes entirely through a 10 mm sieve and at least 85% by weight through a 5 mm sieve. Examples of fine aggregates include those specified by number 2311 in JIS A0203-2014. Specific examples of fine aggregates include one or more types selected from 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 aggregate (artificial and natural), and recycled fine aggregate. Component (B') may be the fine aggregate having a surface water content of -5% or more and less than 0%, which is component (B) of the present invention, and the embodiments described for component (B) of the present invention can be applied as appropriate.

[0058] The content of the (B') component in the premix for hydraulic composition of the present invention is, from the viewpoint of the strength of the set body of the hydraulic composition and hardening acceleration, preferably 40 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 60 parts by mass or more, still more preferably 70 parts by mass or more, and preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and even more preferably 80 parts by mass or less, based on 100 parts by mass of the premix for hydraulic composition.

[0059] In the premix for hydraulic composition of the present invention, the mass ratio (B') / (A) of the content of the component (A) to the content of the component (B') is, from the viewpoints of suppressing cracking of the set body of the hydraulic composition and accelerating hardening, preferably 0.5 or more, more preferably 0.75 or more, even more preferably 1 or more, still more preferably 2 or more, still more preferably 3 or more, and from the viewpoints of strength of the set body of the hydraulic composition and accelerating hardening, preferably 5 or less, more preferably 4.5 or less, even more preferably 4 or less.

[0060] [Method for producing premix for hydraulic composition] The present invention provides a method for producing a premix for a hydraulic composition, which comprises mixing component (A), component (B), component (C), and component (D). The components (A), (B), (C), and (D) are the same as those described in the premix for hydraulic composition of the present invention. The other components other than the components (A) to (D) are also the same and can be mixed in the manufacturing method of the premix for hydraulic composition of the present invention. The mixing amount and mass ratio of each component can be applied to the manufacturing method of the premix for hydraulic composition of the present invention by replacing the content with the mixing amount with respect to the content and mass ratio of each component described in the premix for hydraulic composition of the present invention. The method for producing the premix for hydraulic composition of the present invention can be suitably applied to the aspects described for the premix for hydraulic composition of the present invention.

[0061] In the method for producing the premix for hydraulic composition of the present invention, the components (A), (B), (C), and (D) can be mixed by a known method. Specifically, the components (A), (B), (C), and (D) can be mixed simultaneously. A mixing mixer such as a pan-type forced mixer, a two-shaft forced mixer, a tilting mixer, a ribbon mixer, or a Nauta mixer can be used to mix these components.

[0062] According to the method for producing a premix for a hydraulic composition of the present invention, a premix for a hydraulic composition is produced which contains the components (A), (B'), (C), and (D), and the loss on drying of the premix for a hydraulic composition measured by the above-mentioned method is less than 2.9% by mass.

[0063] [Hydraulic composition] The present invention provides a method for producing a hydraulic composition, which comprises mixing the premix for a hydraulic composition of the present invention with water. The method for producing the hydraulic composition of the present invention can be appropriately applied to the aspects described in the premix for hydraulic composition of the present invention. The premix for hydraulic composition of the present invention may be any of the premix for hydraulic composition of the present invention containing the components (A), (B), (C), and (D), the premix for hydraulic composition of the present invention comprising the components (A), (B), (C), and (D), and the premix for hydraulic composition of the present invention containing the components (A), (B'), (C), and (D), and the premix for hydraulic composition of the present invention having a drying loss of less than 2.9 mass% as measured by the following method.

[0064] In the method for producing a hydraulic composition of the present invention, the ratio of the amount of the (A) component mixed in the premix for hydraulic composition to the amount of water mixed in (water / (A)) [mass percentage (mass%) of water and the (A) component in the hydraulic composition] is, from the viewpoints of hardening acceleration of the hydraulic composition and workability of the hydraulic composition, preferably 20 mass% or more, more preferably 25 mass% or more, even more preferably 30 mass% or more, still more preferably 40 mass% or more, still more preferably 50 mass% or more, still more preferably 60 mass% or more, still more preferably 65 mass% or more, and preferably 100 mass% or less, more preferably 90 mass% or less, still more preferably 80 mass% or less, and still more preferably 75 mass% or less.

[0065] The present invention provides a hydraulic composition comprising the premix for a hydraulic composition of the present invention and water. The hydraulic composition of the present invention can be appropriately applied with the embodiments described in the premix for hydraulic composition of the present invention. The premix for hydraulic composition of the present invention may be any of the premix for hydraulic composition of the present invention containing the components (A), (B), (C), and (D), the premix for hydraulic composition of the present invention comprising the components (A), (B), (C), and (D), and the premix for hydraulic composition of the present invention containing the components (A), (B'), (C), and (D), and the premix for hydraulic composition of the present invention having a drying loss of less than 2.9 mass% as measured by the above method.

[0066] In the hydraulic composition of the present invention, the ratio of the amount of the (A) component in the premix for hydraulic composition to the amount of water (water / (A)) [mass percentage (mass%) of water and the (A) component in the hydraulic composition] is, from the viewpoints of hardening acceleration of the hydraulic composition and workability of the hydraulic composition, preferably 20 mass% or more, more preferably 25 mass% or more, even more preferably 30 mass% or more, still more preferably 40 mass% or more, still more preferably 50 mass% or more, still more preferably 60 mass% or more, still more preferably 65 mass% or more, and preferably 100 mass% or less, more preferably 90 mass% or less, still more preferably 80 mass% or less, still more preferably 75 mass% or less.

[0067] [Dry spraying method] The present invention provides a dry spraying method which comprises mixing the premix for a hydraulic composition of the present invention with water to produce a hydraulic composition, and spraying the hydraulic composition onto an object.

[0068] The dry spraying method of the present invention can be appropriately applied with the embodiments described in the premix for hydraulic composition of the present invention. The premix for hydraulic composition of the present invention may be any of the premix for hydraulic composition of the present invention containing the components (A), (B), (C), and (D), the premix for hydraulic composition of the present invention comprising the components (A), (B), (C), and (D), and the premix for hydraulic composition of the present invention containing the components (A), (B'), (C), and (D), and the premix for hydraulic composition of the present invention having a drying loss of less than 2.9 mass% as measured by the above method. The hydraulic composition in the dry spraying method of the present invention is the same as the hydraulic composition of the present invention, and the aspects described in the hydraulic composition of the present invention and its manufacturing method can be appropriately applied. The ratio of the amount of the component (A) mixed in the premix for hydraulic composition to the amount of water mixed (water / (A)) [mass percentage (mass%) of water and the component (A) in the hydraulic composition] is also in the same range as described in the manufacturing method for the hydraulic composition of the present invention.

[0069] In the spraying method of the present invention, the hydraulic composition prepared by mixing the premix for hydraulic composition of the present invention with water is sprayed onto an object. This method corresponds to a so-called dry spraying method. The dry spraying method of the present invention can be carried out by using conventional spraying equipment. The spraying equipment may be any equipment that can perform dry spraying without any problems. For example, the premix for hydraulic composition of the present invention can be compressed by air and mixed with water in a spraying machine for spraying. EXAMPLES

[0070] The components in the table are as follows: <Component (A)> A-1: Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation, specific gravity 3.16) <(B) component> B-1: Mountain sand (from Joyo City, Kyoto Prefecture, surface dry density 2.51) <(C) component> C-1: Mighty 21PSD (Kao Corporation, polycarboxylate ether powder dispersant)

[0071] <(D) component> D-1: Alcox L-6 (manufactured by Meisei Chemical Industry Co., Ltd., polyethylene oxide, weight average molecular weight: 60,000) D-2: Alcox R-150 (manufactured by Meisei Chemical Industry Co., Ltd., polyethylene oxide, weight average molecular weight: 150,000) D-3: Alcox R-1000 (manufactured by Meisei Chemical Industry Co., Ltd., polyethylene oxide, weight average molecular weight: 325,000) D-4: Alcox E-30 (manufactured by Meisei Chemical Industry Co., Ltd., polyethylene oxide, weight average molecular weight: 475,000) D-5: Alcox E-45 (manufactured by Meisei Chemical Industry Co., Ltd., polyethylene oxide, weight average molecular weight: 800,000) D-6: Alcox EP1010N (manufactured by Meisei Chemical Industry Co., Ltd., random copolymer of ethylene oxide and propylene oxide, weight average molecular weight: 100,000) <Component (D') (comparison component of component (D))> D'-1: Polyethylene oxide, molecular weight 1,000,000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0072] (1) (B) Adjustment of the surface water content of the component The above component (B) was placed in a constant temperature air dryer DRM620DE (manufactured by Advantec Co., Ltd.) and dried at 105°C for 24 hours to obtain an absolutely dry state. It was then cooled to room temperature and spread out, and Wakayama City water was sprayed with a shoulder-mounted sprayer (manufactured by Kinboshi Co., Ltd.) while homogenizing with a shovel, and the surface water ratio measured by the method described in JIS A 1111 was adjusted to be -3.2%, -1.6%, and 0%, respectively. The surface water ratios of the components (B) used are also shown in Table 1. The component with a surface water ratio of 0% is a comparative component of the component (B).

[0073] (2) Preparation of premix for hydraulic composition A premix for a hydraulic composition was prepared by putting the components (A), (B), (C), and (D) or (D') into a Hobart-type mixer according to JIS R 5201 in the amounts (parts by mass) shown in Table 1 and mixing for 20 seconds at 62 rpm. Note that the amounts of the components (C), (D), or (D') in Table 1 relative to 100 parts by mass of (A) are the amounts (parts by mass) of each component relative to 100 parts by mass of the component (A).

[0074] (3) Measurement of drying loss of premix for hydraulic composition 10.0 g of the premix for hydraulic composition prepared by the method described in (2) was weighed out onto an aluminum flat dish, placed in a thermostatic air-blowing dryer DRM620DE (manufactured by Advantec Co., Ltd.), and dried at 105°C for 2 hours. After cooling to room temperature, the mass was measured, and the loss on drying (mass%) was calculated based on the following formula. The results are shown in Table 1. Loss on drying (mass%) = (mass of premix for hydraulic composition before drying (g) - mass of premix for hydraulic composition after drying at 105°C for 2 hours (g)) x 100 / mass of premix for hydraulic composition before drying (g)

[0075] (4) Preparation of hydraulic composition Next, tap water (Wakayama City tap water, specific gravity 1.00) was added to the premix for hydraulic composition prepared by the method described in (2) so as to obtain the water / (A) ratio [the mass percentage (mass%) of water and (A) component in the hydraulic composition] shown in Table 1, and the mixture was further kneaded at 62 rpm for 2 minutes using the Hobart-type mixer described in (2) to prepare a hydraulic composition.

[0076] (5) Evaluation of setting retardation A 20.0 g sample of the hydraulic composition immediately after preparation prepared by the method described in (4) was taken, and the heat of hydration (kJ / g) was measured using an isothermal calorimeter TAM Air (manufactured by TA Instruments), and the time (min) required to reach the second peak of the heat of hydration was used as an index of the setting time. The results are shown in Table 1.

[0077] [Table 1]

[0078] In Table 1, comparing the examples of the present invention with the comparative examples, the examples of the present invention showed a short time to reach the second peak of heat of hydration. This is considered to be because the polyalkylene oxide (D) of the present invention, which has a moderately large weight-average molecular weight, holds water on the surface of the fine aggregate while suppressing the decrease in the surface tension of the aqueous solution, and is unlikely to cause delay in setting due to absorption of water by the fine aggregate. Thus, the premix for hydraulic composition of the present invention is most suitable for the dry spraying method, which requires the premix to contain a dispersant in order to improve the mixability of water and the premix for hydraulic composition in the spraying machine, since the premix is ​​unlikely to cause delay in setting of the hydraulic composition even when the fine aggregate (B) with a surface water ratio of less than 0% and the polycarboxylic acid dispersant (C) are used in combination. Similarly, the premix for hydraulic composition of the present invention uses fine aggregate and a polycarboxylic acid-based dispersant, which is component (C), in combination, and has a drying loss of less than 2.9 mass%, so that it is unlikely to cause delay in setting of the hydraulic composition, and is most suitable for a dry spraying method in which the premix needs to contain a dispersant to improve the mixability of water and the premix for hydraulic composition in the spraying machine. Furthermore, when fine aggregate with a surface water ratio below -5% is used, the fine aggregate will absorb significant water, making it difficult for the water-soluble polymer to suppress the rapid absorption of water by the fine aggregate, and it is thought that the hydration promotion effect will decrease.

Claims

1. A premix for a hydraulic composition comprising (A) cement (hereinafter referred to as component (A)), (B) fine aggregate having a surface water ratio of -5% or more and less than 0% (hereinafter referred to as component (B)), (C) a polycarboxylic acid-based dispersant (hereinafter referred to as component (C)), and (D) a polyalkylene oxide having a weight average molecular weight of 5,000 or more and less than 1,000,000 (hereinafter referred to as component (D)).

2. 2. The premix for a hydraulic composition according to claim 1, wherein a mass ratio (B) / (A) of the content of the component (A) to the content of the component (B) is 0.5 or more and 5 or less.

3. 3. The premix for hydraulic composition according to claim 1 or 2, wherein the content of the component (A) is 10 parts by mass or more and 60 parts by mass or less per 100 parts by mass of the premix for hydraulic composition.

4. The premix for hydraulic composition according to claim 1 or 2, wherein the content of the component (B) is 40 parts by mass or more and 90 parts by mass or less per 100 parts by mass of the premix for hydraulic composition.

5. 3. The premix for a hydraulic composition according to claim 1 or 2, wherein the content of the component (C) is 0.05 parts by mass or more and 1 part by mass or less per 100 parts by mass of the component (A).

6. 3. The premix for a hydraulic composition according to claim 1 or 2, wherein the content of the component (D) is 0.05 parts by mass or more and 2 parts by mass or less per 100 parts by mass of the component (A).

7. 3. The premix for a hydraulic composition according to claim 1 or 2, wherein the weight average molecular weight of the component (D) is 50,000 or more and 600,000 or less.

8. The premix for a hydraulic composition according to claim 1 or 2, which is for dry spraying.

9. A premix for a hydraulic composition comprising (A) cement (hereinafter referred to as component (A)), (B) fine aggregate having a surface water ratio of -5% or more and less than 0% (hereinafter referred to as component (B)), (C) a polycarboxylic acid-based dispersant (hereinafter referred to as component (C)), and (D) a polyalkylene oxide having a weight average molecular weight of 5,000 or more and less than 1,000,000 (hereinafter referred to as component (D)).

10. A premix for a hydraulic composition comprising (A) cement (hereinafter referred to as (A) component), (B') fine aggregate (hereinafter referred to as (B') component), (C) a polycarboxylic acid-based dispersant (hereinafter referred to as (C) component), and (D) a polyalkylene oxide having a weight average molecular weight of 5,000 or more and less than 1,000,000 (hereinafter referred to as (D) component), wherein the premix for a hydraulic composition has a drying loss of less than 2.9% by mass as measured by the following method. Loss on drying: Loss on drying (mass%) calculated by the following formula after drying the premix for hydraulic composition at 105° C. for 2 hours in a constant temperature air dryer Loss on drying (mass%)=(mass of premix for hydraulic composition before drying (g)−mass of premix for hydraulic composition after drying at 105° C. for 2 hours (g))×100 / mass of premix for hydraulic composition before drying (g)

11. A method for producing a premix for a hydraulic composition, comprising mixing (A) cement (hereinafter referred to as (A) component), (B) fine aggregate having a surface water ratio of -5% or more and less than 0% (hereinafter referred to as (B) component), (C) a polycarboxylic acid-based dispersant (hereinafter referred to as (C) component), and (D) a polyalkylene oxide having a weight-average molecular weight of 5,000 or more and less than 1,000,000 (hereinafter referred to as (D) component).

12. The method for producing a premix for a hydraulic composition according to claim 11, wherein the component (B) is fine aggregate whose surface moisture content has been adjusted to -5% or more and less than 0% by heat drying treatment.

13. A method for producing a hydraulic composition, comprising mixing the premix for a hydraulic composition according to claim 1 or 2 with water.

14. A dry spraying method comprising mixing the premix for hydraulic composition according to claim 1 or 2 with water to produce a hydraulic composition, and spraying the hydraulic composition onto an object.

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