Water-based heat inhibitors for hydraulic components

Abstract

To provide a hydration heat inhibitor for hydraulic composition which can be applied to the formulation of general-purpose hydraulic compositions such as Portland cement, which can sufficiently inhibit the hydration heat and produce concrete and mortar with excellent strength development, with little change in the fluidity of the hydraulic composition.SOLUTION: The present invention provides a hydration heat inhibitor for hydraulic composition containing (A) a polycarboxylic acid-based copolymer or its salt (a), preferably (B) a hydroxyl group-containing compound such as glycol or polyalcohol, and (C) other dispersants. The hydration heat inhibitor can sufficiently inhibit the hydration heat with little change in the fluidity of the hydraulic composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a hydration heat inhibitor for hydraulic compositions. [Background technology]

[0002] When constructing large-scale concrete structures such as dams and bridge piers (mass concrete), the heat generated by the hydration reaction of cement can create a temperature difference between the inside and outside of the concrete, potentially causing cracks to form.

[0003] Conventionally, methods for controlling this heat of hydration include cooling the materials used, pipe cooling after concrete placement, the use of admixtures such as fly ash, and the use of admixtures such as heat absorbers and cement hydration reaction inhibitors.

[0004] Among these methods for controlling the heat of hydration, as an example of a hydration reaction inhibitor, Patent Document 1 proposes a hydration heat inhibitor capsule in which a setting retarder component is coated with a poorly soluble coating material such as paraffin, and a method for manufacturing the same capsule.

[0005] Patent Document 2 provides an example of a cement composition in which a tannin compound and an oxycarboxylate salt are added to ordinary Portland cement, thereby suppressing the exothermic reaction of hydration and preventing a decrease in strength when the cement hardens.

[0006] Patent Document 3 describes that a cement admixture having a specific expanding substance and a hydration heat inhibitor component such as dextrin can suppress the hydration heat of cement without reducing its strength development.

[0007] Patent Document 4 proposes a hydration heat inhibitor for hydraulic compositions containing a specific anionic surfactant and a polyoxyalkylene alkyl or alkenyl ether having an HLB value of 2 or more and less than 9, which suppresses the temperature rise due to hydration heat without delaying the time to reach the maximum temperature. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2020-200200 [Patent Document 2] Japanese Patent Publication No. 2013-234086 [Patent Document 3] Japanese Patent Publication No. 2017-165627 [Patent Document 4] Japanese Patent Publication No. 2019-196282 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] The hydration heat suppression capsule disclosed in Patent Document 1 contains a large amount of setting retarder components, and even when using the hydration heat suppression capsule, it may delay the start time of the hydration reaction. Therefore, it may take time for concrete structures to harden and develop strength. The cement composition disclosed in Patent Document 2 can suppress hydration heat, but its strength development is inferior due to hydration delay, and furthermore, the effect on fluidity of concrete is not considered, making it difficult to use in actual construction. The cement admixture in Patent Document 3 suppresses the decrease in strength development by adding an expanding substance in addition to a hydration heat suppressant component such as dextrin, from the viewpoint of construction method. However, the decrease in concrete fluidity due to the expanding substance, which is generally considered, has not been considered. Furthermore, in Patent Document 4, a surfactant-based hydration heat suppressant that does not contain hydration retarder components such as sodium gluconate and dextrin is proposed to solve these hydration delay issues, but the fluidity of mortar is not considered at all, and there is room for improvement regarding its workability when combined with actual concrete dispersants.

[0010] Therefore, in order to solve the above problems, the present invention aims to provide a hydration heat inhibitor that can be applied to the formulation of general-purpose hydraulic compositions such as Portland cement, and that can suppress the hydration heat of a hydraulic composition without significantly affecting the fluidity of the hydraulic composition, even when the hydration heat inhibitor is added to the hydraulic composition. [Means for solving the problem]

[0011] As a result of diligent research to achieve the above objective, the present inventors have found that a polycarboxylic acid copolymer or a salt thereof containing a constituent unit having an alkenyl group with a specific number of carbon atoms and 2-hydroxypropyl acrylate can exhibit a hydration heat suppression effect when used in a hydraulic composition, thereby solving the above problem, and thus arrived at the present invention.

[0012] In other words, the present invention provides the following [1] to [8]. [1] A hydration heat inhibitor for hydraulic compositions, containing the following component (A). (A) Ingredients: A polycarboxylic acid copolymer or a salt thereof obtained by copolymerizing 1 to 80% by weight of monomer (I) represented by the following general formula (1), 20 to 97% by weight of 2-hydroxypropyl acrylate monomer (II), and 0 to 50% by weight of other monomer (III) copolymerizable with monomers (I) to (II). R 1 -O-(A 1 O) n1 -R 2 ...(1) (In the formula, R 1 This represents an alkenyl group with 2 to 5 carbon atoms. 1 O represents an oxyalkylene group with 2 to 18 carbon atoms, either identical or different. n1 is the average number of moles of oxyalkylene groups added, and represents a number from 1 to 200. R 2 (This represents a hydrogen atom or a hydrocarbon group with 1 to 30 carbon atoms.) [2] The hydration heat inhibitor for hydraulic compositions according to [1], wherein the weight-average molecular weight of the polycarboxylic acid copolymer or its salt (a) is 5,000 to 300,000 in terms of polyethylene glycol. [3] (B) component: a hydrate heat inhibitor for hydraulic compositions according to [1] or [2], further comprising a hydroxyl group-containing compound. The heat of hydration inhibitor for hydraulic compositions according to [3], which contains the weight ratio (B) / (A) of component (B) to component (A) in a blending amount of 0.01 or more and 5.0 or less. The heat of hydration inhibitor for hydraulic compositions according to [3] or [4], wherein component (B) contains at least one selected from ethylene glycol and glycerol. The heat of hydration inhibitor for hydraulic compositions according to any one of [1] to [5], further containing a dispersant other than components (A) and (B) as component (C). The heat of hydration inhibitor for hydraulic compositions according to [6], wherein component (C) contains at least one selected from polycarboxylic acid polymers (excluding copolymers or their salts (a)), lignin sulfonic acid polymers, and naphthalene sulfonic acid polymers. The heat of hydration inhibitor for hydraulic compositions according to any one of [1] to [7], wherein the hydraulic composition is mass concrete.

Advantages of the Invention

[0013] According to the present invention, a heat of hydration inhibitor can be provided that can be applied to general-purpose hydraulic compositions such as Portland cement, and can lower the maximum temperature reached by the temperature rise due to the heat of hydration without substantially changing the fluidity of the hydraulic composition. By applying the agent of the present invention to a hydraulic composition such as mass concrete, it is expected to suppress the occurrence of problems such as thermal cracking and strength reduction.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, the present invention will be described in detail according to its preferred embodiments. In this specification, the notation "AA to BB" indicates AA or more and BB or less.

[0015] [1. Heat of hydration inhibitor] The agent of the present invention has component (A) as an active ingredient. Thereby, it is possible to suppress the temperature rise due to the heat of hydration and the hydration reaction immediately after kneading without changing the fluidity of the hydraulic composition.

[0016] <(A) component> Component (A) is a polycarboxylic acid copolymer or a salt thereof (a) (hereinafter referred to as the copolymer or its salt (a)). The copolymer or its salt (a) is a copolymer of monomers (I) to (II) or (I) to (III), and its structure contains constituent units derived from each monomer.

[0017] -Weight ratio of each monomer- The weight ratio of each monomer in the copolymer or its salt (a) (weight ratio when the sum of monomers (I) to (III) is 100% by weight) is as follows: Monomer (I) is preferably 1% by weight or more, more preferably 3% by weight or more, and even more preferably 5% by weight or more. The upper limit is preferably 80% by weight or less, more preferably 70% by weight or less, and even more preferably 50% by weight or less.

[0018] The monomer (II) is preferably 20% by weight or more, more preferably 30% by weight or more, and even more preferably 40% by weight or more. The upper limit is preferably 97% by weight or less, more preferably 95% by weight or less, and even more preferably 90% by weight or less.

[0019] The monomer (III) is preferably 50% by weight or less, more preferably 40% by weight or less. There is no particular lower limit, and it may be 0% by weight.

[0020] The ratio of the weight of monomer (II) to the weight of monomer (I) ((II) / (I)) is preferably 1% by weight or more, and preferably 1000% by weight or less. The ratio of the weight of monomer (III) to the weight of monomer (I) ((III) / (I)) is preferably 200% by weight or less. There is no particular lower limit; it should be 0% by weight or more.

[0021] The above weight ratios typically correspond to the ratio of the amounts used when polymerizing the monomers.

[0022] -Monomer(I): Polyalkylene glycol monoalkenyl ether- The monomer (I) is a polyalkylene glycol monoalkenyl ether represented by the following general formula (1). R 1 -O-(A 1 O) n1 -R 2 ···(1)

[0023] In the general formula (1), R 1 represents an alkenyl group having 2 to 5 carbon atoms. The number of carbon atoms of the alkenyl group is usually 2 or more, preferably 3 or more. The upper limit is preferably 5 or less. The alkenyl group may have one or more double bonds and may be either linear or branched. Examples of R 1 include, for example, an allyl group, a methallyl group, and the residue of 3-methyl-3-buten-1-ol, and an allyl group is preferred, but not limited thereto.

[0024] In the general formula (1), A 1 O represents an oxyalkylene group, which may be the same or different. The number of carbon atoms of the oxyalkylene group is usually 2 to 18, for example, 2 to 16, 2 to 14, 2 to 12, 2 to 10, or 2 to 8, preferably 2 to 6, more preferably 2 to 4. Examples of the oxyalkylene group include an oxyethylene group (ethylene glycol unit), an oxypropylene group (propylene glycol unit), and an oxybutylene group (butylene glycol unit), and an oxyethylene group (ethylene glycol unit) and an oxypropylene group (propylene glycol unit) are preferred.

[0025] The above "the same or different" means that when a plurality of A 1 O are contained in the general formula (1) (when n1 is 2 or more), each A 1 O may be the same oxyalkylene group or different (two or more types) oxyalkylene groups. When A 1In the case where multiple O groups are present, examples include a mixture of two or more oxyalkylene groups selected from the group consisting of oxyethylene groups (ethylene glycol units), oxypropylene groups (propylene glycol units), and oxybutylene groups (butylene glycol units). Preferably, the mixture consists of oxyethylene groups (ethylene glycol units) and oxypropylene groups (propylene glycol units), or oxyethylene groups (ethylene glycol units) and oxybutylene groups (butylene glycol units), and more preferably, oxyethylene groups (ethylene glycol units) and oxypropylene groups (propylene glycol units). In the embodiment where different oxyalkylene groups are present, the addition of two or more types of oxyalkylene groups may be in a block-like manner or in a random manner. When oxyethylene groups and oxypropylene groups are present together, the ratio of the average number of moles of oxyethylene groups to oxypropylene groups added is preferably 50-99.9% / 50-0.1%.

[0026] In general formula (1), n1 is the average number of moles of oxyalkylene groups added, and represents a number from 1 to 200. n1 is usually 1 or more, preferably 5 or more, and more preferably 8 or more. The upper limit is usually 200 or less, or 100 or less, or 80 or less, preferably 70 or less, or 50 or less, and more preferably 40 or less. In this specification, the average number of moles of oxyalkylene groups added means the average number of moles of alkylene glycol units added to 1 mole of monomer.

[0027] R in general formula (1) 2 R represents a hydrogen atom or a hydrocarbon group. The number of carbon atoms is preferably 30 or less, more preferably 10 or less, and even more preferably 5 or less. This allows for sufficient cement dispersibility. The lower limit is usually 1 or more, and is not particularly limited. 2 It is preferable that this is a hydrogen atom or a methyl group.

[0028] Examples of monomer (I) include (poly)ethylene glycol allyl ether, (poly)ethylene glycol metharyl ether, (poly)ethylene glycol 3-methyl-3-butenyl ether, (poly)ethylene (poly)propylene glycol allyl ether, (poly)ethylene (poly)propylene glycol metharyl ether, (poly)ethylene (poly)propylene glycol 3-methyl-3-butenyl ether, (poly)ethylene (poly)butylene glycol allyl ether, (poly)ethylene (poly)butylene glycol metharyl ether, (poly)ethylene (poly)butylene glycol 3-methyl-3-butenyl ether, methoxy (poly)ethylene glycol allyl ether, methoxy (poly)ethylene glycol metharyl ether, methoxy Examples include ethylene(poly)ethylene glycol 3-methyl-3-butenyl ether, methoxy(poly)ethylene(poly)propylene glycol allyl ether, methoxy(poly)ethylene(poly)propylene glycol metharyl ether, methoxy(poly)ethylene(poly)propylene glycol 3-methyl-3-butenyl ether, methoxy(poly)ethylene(poly)butylene glycol allyl ether, methoxy(poly)ethylene(poly)butylene glycol metharyl ether, methoxy(poly)ethylene(poly)butylene glycol 3-methyl-3-butenyl ether, (poly)ethylene glycol(poly)propylene glycol monoallyl ether, and ethylene oxide propylene oxide adducts of 3-methyl-3-buten-1-ol. As monomer (I), one or more of these may be used, but it is preferable to include one or more selected from (poly)ethylene glycol (meth)allyl ether, (poly)ethylene glycol 3-methyl-3-butenyl ether, and (poly)ethylene (poly)propylene glycol allyl ether, in order to achieve an excellent balance of hydrophilicity and hydrophobicity in the copolymer or its salt (a). In this specification, "(poly)" means that one or more of the constituent or raw materials described immediately after it are bonded together. Also, in this specification, "(meth)allyl" means "allyl or methallyl".

[0029] Monomer (I) may be a single monomer represented by general formula (1) or a combination of two or more monomers.

[0030] -Monomer(II):2-Hydroxypropylacrylate- Monomer (II) is 2-hydroxypropyl acrylate. Industrially produced 2-hydroxypropyl acrylate may contain 2-hydroxy-1-methylethyl acrylate due to the manufacturing process, and it is not easy to determine their compositional ratio industrially. Therefore, monomer (II) may contain 2-hydroxy-1-methylethyl acrylate as a minor component.

[0031] -Monomer(III): Other monomers- Monomer (III) is any other monomer copolymerizable with monomers (I) to (II). Monomer (III) is not particularly limited as long as it is a monomer copolymerizable with one or more monomers selected from the group consisting of monomers (I) and (II). Note that monomer (III) does not include monomers (I) and monomer (II).

[0032] Examples of monomer (III) include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and their salts (e.g., monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts), dicarboxylic acids such as maleic acid and fumaric acid, and their salts (e.g., monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts), ester compounds having polyalkylene glycol chains (e.g., compounds represented by the general formula (2) below), and diallylbisphenol represented by the general formula (3) below. Monomer (III) may be one or more of these, and it is preferable to use at least one monomer selected from acrylic acid or its salts, methacrylic acid or its salts, and methoxypolyethylene glycol methacrylate.

[0033] General formula (2): [ka] (In general formula (2), R 3 , R 4 and R 5 Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. m represents an integer between 0 and 2. A 2 O represents an oxyalkylene group having 2 to 18 carbon atoms, which may be the same or different. n2 represents the average number of moles of oxyalkylene groups added, and is a number between 1 and 200. X represents a hydrogen atom or a hydrocarbon group with 1 to 30 carbon atoms.

[0034] An example of an ester compound represented by general formula (2) is methoxypolyethylene glycol methacrylate.

[0035] General formula (3): [ka] (In general formula (3), X represents a methylene group, an isopropylidene group, or a sulfonyl group. R 6 (These represent, either identical or distinct, hydrogen atoms or methyl groups.)

[0036] Examples of diallylbisphenols represented by general formula (3) include 3- and 3-position allyl substitutions of 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylmethane, and 4,4'-dihydroxydiphenylsulfone.

[0037] Monomer (III) may be a single type of monomer or a combination of two or more types.

[0038] -Method for producing a copolymer or a salt thereof (a)- Copolymers or their salts (a) can be produced by copolymerizing each predetermined monomer by known methods. Examples of such methods include polymerization in a solvent and bulk polymerization.

[0039] Examples of solvents used in polymerization in a solvent include water; lower alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as cyclohexane and n-hexane; esters such as ethyl acetate; and ketones such as acetone and methyl ethyl ketone. From the viewpoint of solubility of the raw material monomers and the resulting copolymer, it is preferable to use one or more selected from the group consisting of water and lower alcohols, and among these, the use of water is more preferable.

[0040] When copolymerization is carried out in a solvent, each monomer and polymerization initiator may be added dropwise to the reaction vessel in a continuous manner, or a mixture of each monomer and polymerization initiator may be added dropwise to the reaction vessel in a continuous manner. Alternatively, the solvent may be placed in the reaction vessel, and a mixture of monomers and solvent, along with a polymerization initiator solution, may be added dropwise to the reaction vessel in a continuous manner, or some or all of the monomers may be placed in the reaction vessel, and the polymerization initiator may be added dropwise.

[0041] When copolymerization is carried out in a solvent, it is preferable to mix each monomer in a separate container placed before the reaction vessel, and then continuously add the mixture dropwise to the reaction vessel.

[0042] (A) Component: The polycarboxylic acid copolymer or its salt (a) may be used as a hydration heat inhibitor for hydraulic compositions in its original state, including the reaction solvent, after the copolymerization reaction is complete, or it may be used after further processing. Examples of processing include adjusting the concentration by removing the reaction solvent, concentrating, diluting, purifying, and adjusting the pH. After the reaction is complete, it is preferable to adjust the concentration and / or pH in a container placed downstream of the reaction vessel. There are no particular limitations on the method of concentration adjustment, but for example, it may be done by concentration and dilution by adding water. pH adjustment will be described later.

[0043] Polymerization initiators that can be used in copolymerization include, for example, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; and water-soluble organic peroxides such as t-butyl hydroperoxide and hydrogen peroxide, when copolymerization is carried out in an aqueous solvent. In this case, accelerators such as sodium bisulfite and Mohr's salt, and reducing agents such as ascorbic acid and monosaccharides can also be used in combination. Furthermore, when copolymerization is carried out in solvents such as lower alcohols, aromatic hydrocarbons, aliphatic hydrocarbons, esters, or ketones, peroxides such as benzoyl peroxide and lauryl peroxide; hydroperoxides such as cumene peroxide; and aromatic azo compounds such as azobisisobutyronitrile can be used as polymerization initiators. In this case, accelerators such as amine compounds can also be used in combination. In addition, when copolymerization is carried out in a water-lower alcohol mixed solvent, the aforementioned polymerization initiators, or combinations of polymerization initiators and accelerators, can be appropriately selected and used. The polymerization temperature varies depending on the polymerization conditions such as the solvent used and the type of polymerization initiator, but is usually carried out in the range of 50 to 120°C.

[0044] Furthermore, in copolymerization, the molecular weight can be adjusted using a chain transfer agent as needed. Examples of chain transfer agents that can be used include known thiol compounds such as mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, and 2-mercaptoethanesulfonic acid; lower oxides and salts of phosphorous acid, hypophosphorous acid and its salts (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, bisulfite, dithionite, metabisulfite and its salts (sodium sulfite, potassium sulfite, sodium bisulfite, potassium bisulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, potassium metabisulfite, etc.); and the like. These may be used individually or in combination of two or more. Furthermore, in order to adjust the molecular weight of the polycarboxylic acid copolymer or its salt (a), it is also effective to use monomer (III) with even higher chain mobility as the monomer to obtain each of them. Examples of monomers (III) with high chain mobility include (meth)allylsulfonic acid (salt) monomers. The proportion of monomer (III) in the polycarboxylic acid copolymer or its salt (a) is usually 20% by weight or less, and preferably 10% by weight or less. The above proportion for (A) is the proportion when the proportion of monomer (I) + the proportion of monomer (II) + the proportion of monomer (III) = 100% by weight.

[0045] When copolymerizing in an aqueous solvent, the pH during polymerization is usually strongly acidic due to the influence of monomers with unsaturated bonds, but this can be adjusted to an appropriate pH. If pH adjustment is necessary during polymerization, acidic substances such as phosphoric acid, sulfuric acid, nitric acid, alkyl phosphoric acid, alkyl sulfuric acid, alkyl sulfonic acid, and (alkyl)benzenesulfonic acid can be used to adjust the pH. Among these acidic substances, phosphoric acid is preferred due to its pH buffering effect. However, in order to eliminate the instability of the ester bonds in ester monomers, it is preferable to perform polymerization at a pH of 2 to 7. There are no particular limitations on the alkaline substances that can be used to adjust the pH, but alkaline substances such as NaOH and Ba(OH)2 are common. pH adjustment may be performed on the monomers before polymerization or on the copolymer solution after polymerization. Alternatively, some alkaline substances may be added before polymerization, and then the pH of the copolymer may be further adjusted.

[0046] -salt- Examples of salts in the copolymer or its salt (a) include monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts.

[0047] -Weight-average molecular weight of copolymer or its salt (a)- The weight-average molecular weight of the copolymer or its salt (a) is preferably 5,000 or more, more preferably 6,000 or more, even more preferably 8,500 or more, and even more preferably 10,000 or more. This allows for the suppression of hydration heat without significantly changing the fluidity of the hydraulic composition, and the desired effect as a hydration heat inhibitor can be fully expressed. The upper limit of the weight-average molecular weight is preferably 300,000 or less, more preferably 250,000 or less, and even more preferably 200,000 or less. This reduces the viscosity imparted to the hydraulic composition without significantly changing its fluidity, thus improving workability.

[0048] The weight-average molecular weight in this invention can be measured by a known method of converting it to polyethylene glycol using gel permeation chromatography (GPC).

[0049] The following conditions can be cited as examples of GPC measurement conditions. The weight-average molecular weight in the examples described later is the value measured under these conditions. Measuring device; manufactured by Tosoh Corporation. Columns used: ShoCex Bolumn OH-pak SB-806HQ, SB-804HQ, SB-802.5HQ Eluent: 0.05 mM sodium nitrate / acetonitrile 8 / 2 (v / v) Standard material: Polyethylene glycol (manufactured by Tosoh Corporation and GL Science Corporation) Detector; Differential refractometer (manufactured by Tosoh Corporation) Calibration curve; based on polyethylene glycol.

[0050] Component (A) may be a single copolymer or a salt thereof (a), or a combination of two or more different copolymers.

[0051] -(A) Content of component- The content of component (A) in the agent of the present invention may be any effective amount, but is preferably 10% by weight or more relative to the total weight of the hydration heat inhibitor. There is no particular upper limit, but it is 100% by weight or less.

[0052] -(A) Amount of ingredient used- When the agent of the present invention is added to a hydraulic composition (usually containing a hydraulic material), the amount used (amount added, amount blended) of component A) per 100 parts by weight of the hydraulic material (e.g., cement) is usually 0.01 parts by weight or more, preferably 0.02 parts by weight or more, and more preferably 0.05 parts by weight or more. This allows the desired effect to be sufficiently obtained. There is no particular upper limit, but from an economic standpoint, it is usually 5.0 parts by weight or less, preferably 2.0 parts by weight or less, and more preferably 1.0 part by weight or less. Therefore, the amount used is usually 0.01 to 5.0 parts by weight, preferably 0.02 to 2.0 parts by weight, and more preferably 0.05 to 1.0 parts by weight. This brings about various desirable effects in the resulting hydraulic composition, such as reduction of hydration heat, stabilization of fluidity, increase in strength, and improvement of durability.

[0053] -(A) Action of component - Component (A) can exert a hydration heat suppression effect. This hydration heat suppression effect can be exerted on hydraulic compositions. Specifically, for example, it can suppress the temperature rise due to hydration heat without changing the fluidity of the hydraulic composition. The mechanism by which such an effect is exerted is presumed to be as follows. Component (A) adsorbs onto the surface of the hydraulic composition (e.g., cement particles) and covers the surface, thereby preventing rapid contact between the hydraulic composition and water. The copolymer or its salt (a) as component (A) does not have strong anionic functional groups such as carboxyl groups and does not contribute to the dispersibility of the hydraulic composition. Therefore, it is possible to suppress the hydration reaction immediately after mixing without changing the fluidity of the hydraulic composition. Furthermore, the copolymer or its salt (a) can express carboxyl groups over time through hydrolysis in the alkaline hydraulic composition. These carboxyl groups can capture ions such as calcium ions and aluminum ions necessary for the hydration reaction, thereby suppressing the hydration reaction over a long period. It is presumed that the hydration heat suppression effect is exerted through this mechanism.

[0054] <(B) Component: Hydroxyl group-containing compound> The agent of the present invention preferably further contains component (B). Component (B) is a hydroxyl group-containing compound. By including component (B), the hydration heat suppression effect can be further improved, and the control of fluidity can be made easier.

[0055] -Examples of hydroxyl group-containing compounds- A hydroxyl group-containing compound can be any compound that has a hydroxyl group (e.g., an alcoholic hydroxyl group) in one molecule. Examples include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, butylene glycol, diethanolamine, polyglycidol, glycerol (glycerin), polyglycerol (polyglycerin), trimethylolethane, trimethylolpropane, 1,3,5-pentatriol, erythritol, pentaerythritol, dipentaerythritol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, and mannitol. Other suitable examples include hexoses such as glucose, fructose, mannose, indos, sorbose, gross, talose, tagatose, galactose, allose, psicose, and altrose; pentoses such as arabinose, ribulose, ribose, xylose, xylulose, and lyxose; tetroses such as threose, erythrulose, and erythrose; other sugars such as rhamnose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gentianose, and melegitose; and their sugar alcohols and sugar acids (sugars; glucose, sugar alcohols; glucose, sugar acids; gluconic acid). Furthermore, derivatives such as partially etherified and partially esterified versions of these exemplary compounds are also suitable. Among these, compounds having two or more hydroxyl groups are preferred, and from the viewpoint of industrial production efficiency, ethylene glycol, glycerol, triethanolamine, and sodium gluconate are preferred, with ethylene glycol and glycerol being more preferred.

[0056] Component (B) may be one hydroxyl group-containing compound or a combination of two or more different compounds.

[0057] -(B) Content of component - The weight ratio of the content of component (B) to component (A) ((B) / (A)) is preferably 0.0 1 with Above, more comfortable 0.0 5 More preferably 0. 1 with This is the case. This allows for a sufficient improvement in the hydration heat suppression effect due to the addition of component (B). The upper limit is preferably 5. 0 with More preferably, 4. 0 with Below, more preferably 3. 0 with This is the result. This suppresses the occurrence of the rapid setting effect of the hydraulic composition and prevents a decrease in the fluidity of the hydraulic composition.

[0058] -(B) Amount of ingredient used- When the agent of the present invention is added to a hydraulic composition, the amount used (amount added, amount blended) of component (B) per 100 parts by weight of the hydraulic material (e.g., cement) is usually 0.01 parts by weight or more, preferably 0.02 parts by weight or more, and more preferably 0.05 parts by weight or more. This allows for a sufficient improvement in the hydration heat suppression effect due to the addition of component (B). The upper limit is usually 5.0 parts by weight or less, preferably 2.0 parts by weight or less, and more preferably 1.0 part by weight or less. This suppresses the rise in hydration heat due to the acceleration of the initial hydration reaction. Therefore, the amount used is usually 0.01 to 5.0 parts by weight, preferably 0.02 to 2.0 parts by weight, and more preferably 0.05 to 1.0 parts by weight. By using this amount, a large change in the fluidity of the resulting hydraulic composition can be suppressed, which is also preferable from the viewpoint of workability.

[0059] -(B) Action of component - The reason why component (B) can further improve the hydration heat suppression effect together with component (A) is presumed to be as follows: The hydroxyl groups of component (B) (e.g., alcoholic hydroxyl groups) form stronger chelates with multiple carboxyl groups of hydrolyzed component (A) and ions such as calcium ions and aluminum ions in the hydraulic composition. This is presumed to result in a superior hydration heat suppression effect.

[0060] <(C) Component: Other dispersants> The agent of the present invention preferably further comprises component (C), which is another dispersant (other than components (A) and (B)). Other dispersants for hydraulic compositions (cement dispersants) include, for example, polycarboxylic acid polymers (excluding copolymers or their salts (a)), naphthalene sulfonic acid polymers (e.g., naphthalene sulfonic acid formaldehyde condensate), melamine sulfonic acid polymers (e.g., melamine sulfonic acid formaldehyde condensate), and lignin sulfonic acid polymers (e.g., lignin sulfonate salts). Preferably, the dispersants are polycarboxylic acid polymers, naphthalene sulfonic acid polymers, and lignin sulfonic acid polymers, and more preferably polycarboxylic acid polymers. The amount used (addition amount, blending amount) per 100 parts by weight of component (C) hydraulic material (e.g., cement) is usually 0.01 parts by weight or more, preferably 0.05 parts by weight or more, and more preferably 0.1 parts by weight or more. The upper limit is usually 5 parts by weight or less, preferably 3 parts by weight or less, and more preferably 2 parts by weight or less.

[0061] -Optional ingredients- The agent of the present invention may optionally contain other components. Other components may be anything other than components (A) and (B) described above, and include known concrete additives such as other hydraulic dispersants (cement dispersants), water-soluble polymers, polymer emulsions, air-entraining agents, cement wetting agents, expanding agents, waterproofing agents, retarders, thickeners, flocculants, drying shrinkage reducing agents, strength enhancers, hardening accelerators, defoamers, air-entraining agents, and other surfactants. The other components may be used individually or in combination of two or more.

[0062] Examples of water-soluble polymers include polyalkylene glycols and cellulosic compounds, specifically polyethylene polypropylene glycol, polyethylene polybutylene glycol, hydroxyethylcellulose, hydroxymethylcellulose, methylcellulose, and hydroxypropylmethylcellulose. The content of the water-soluble polymer is preferably 0.01% by weight or more relative to the amount of component (A) (or the total amount of components (A) and (B) if component (B) is also included). The upper limit is preferably 50% by weight or less.

[0063] Examples of retarders include oxycarboxylic acids such as gluconic acid (salt) and citric acid (salt). The content of sugar alcohols is preferably 0.01% by weight or more relative to the amount of component (A) (or the total amount of components (A) and (B) if component (B) is also included). The upper limit is preferably 50% by weight or less.

[0064] Examples of curing accelerators include soluble calcium salts such as calcium chloride, calcium nitrite, and calcium nitrate; chlorides such as iron chloride and magnesium chloride; thiosulfates; formic acid; and formate salts such as calcium formate. The content of the curing accelerator is preferably 0.01% by weight or more relative to the amount of component (A) (or the total amount of components (A) and (B) if component (B) is further included). The upper limit is preferably 50% by weight or less.

[0065] Examples of thickening agents include hydroxypropyl methylcellulose, methylcellulose, carboxymethylcellulose, cellulose nanofiber, and cellulose nanocrystal. The content of the thickening agent is preferably 0.01% by weight or more, and preferably 50% by weight or less, relative to the amount of component (A) (or the total amount of components (A) and (B) if component (B) is further included).

[0066] [2. Method for manufacturing the agent] The dosage form of the agent of the present invention is not particularly limited, but examples include solid (e.g., powder, pellet), semi-solid (e.g., gel), and liquid (e.g., solution (aqueous solution), dispersion, suspension). In the case of a liquid, the solvent for dissolving each component may be selected as needed. A dispersant may also be included as needed. If the agent contains components (A) and (B), the two components may be in a mixed state, or they may be packaged separately and exist in a form that allows for mixing or sequential addition of the two components at the time of use.

[0067] [3. Hydraulic composition] The agent of the present invention can be used by adding it to a hydraulic composition. The hydraulic composition may be any composition containing a hydraulic material such as cement, gypsum (e.g., hemihydrate gypsum, dihydrate gypsum, etc.), or dolomite. Cement is a common hydraulic material.

[0068] Examples of cement include Portland cement (ordinary, rapid-hardening, ultra-rapid-hardening, moderate-heat, sulfate-resistant, and their respective low-alkali forms), various blended cements (blast furnace cement, silica cement, fly ash cement), white Portland cement, alumina cement, ultra-rapid-hardening cement (1-clinker rapid-hardening cement, 2-clinker rapid-hardening cement, magnesium phosphate cement), grout cement, oil well cement, low-heat cement (low-heat blast furnace cement, fly ash-mixed low-heat blast furnace cement, beelite-high content cement), ultra-high-strength cement, cement-based solidifying agents, and eco-cement (cement manufactured using one or more of the following as raw materials: municipal solid waste incineration ash, sewage sludge incineration ash). Cement may also contain added materials such as blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, limestone powder, and other fine powders, as well as gypsum.

[0069] The hydraulic composition may contain aggregate. The aggregate may be either fine aggregate or coarse aggregate. Examples of aggregate include sand, gravel, crushed stone; granulated slag; recycled aggregate, etc.; and refractory aggregates such as silica, clay, zircon, high alumina, silicon carbide, graphite, chromium, chromomagnesia, and magnesia.

[0070] Examples of hydraulic compositions include cement compositions such as cement paste, mortar, concrete, and plaster. Specifically, examples of hydraulic compositions include ready-mixed concrete, concrete for precast concrete products, concrete for centrifugal molding, concrete for vibration compaction, steam-cured concrete, sprayed concrete, and mass concrete used in structures such as bridge piers and anchors of long bridges, foundations of high-rise buildings, LNG tanks, and bases of nuclear power plants, with mass concrete being preferred. Other examples include medium-flow concrete (concrete with a slump value in the range of 22 to 25 cm), high-flow concrete (concrete with a slump value of 25 cm or more and a slump flow value in the range of 50 to 70 cm), self-compacting concrete, and mortars or concrete requiring high fluidity such as self-leveling materials.

[0071] <Amount of agent to be added to the hydraulic composition> The amount of the agent added (blended amount) per 100 parts by weight of a hydraulic material such as cement is usually 0.05 parts by weight or more, preferably 0.1 parts by weight or more, and more preferably 0.2 parts by weight or more. This allows for a sufficient hydration heat suppression effect on the hydraulic composition. The upper limit is usually 8.0 parts by weight or less, preferably 5.0 parts by weight or less, and more preferably 3.0 parts by weight or less. This allows the fluidity of the hydraulic composition to be maintained within a moderate range that does not affect the actual construction. Therefore, it is usually 0.05 to 8.0 parts by weight, preferably 0.1 to 5.0 parts by weight, and more preferably 0.2 to 3.0 parts by weight. This is preferable not only from the viewpoint of hydration heat suppression, but also from the viewpoint of workability, as the fluidity of the resulting hydraulic composition does not change significantly.

[0072] <Method for adding an agent to a hydraulic composition> The agent of the present invention can be used by adding it to a hydraulic composition. The method of addition is not particularly limited, and it may be added together with other materials such as hydraulic materials (base cement) or added afterward. It may also be added during the mixing of each material of the hydraulic composition, or added after mixing. [Examples]

[0073] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these. Unless otherwise specified in the examples, % refers to weight percent, and parts refers to parts by weight. Furthermore, "weight ratio of monomers in copolymer" refers to the blending ratio of monomers used to obtain the copolymer.

[0074] <(A) component> <Manufacturing Example 1> Production of polycarboxylic acid copolymer (A-1) 156 parts of water and 42 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added: 10) were charged into a glass reaction vessel equipped with a thermometer, stirrer, reflux apparatus, nitrogen inlet tube, and dropper. The reaction vessel was heated to 100°C under stirring. Subsequently, an aqueous monomer solution prepared by mixing 2 parts of acrylic acid, 98 parts of 2-hydroxypropyl acrylate, and 65 parts of water, and a mixture of 1 part of ammonium persulfate and 39 parts of water were continuously added dropwise to the reaction vessel, which was maintained at 100°C, over a period of 1 hour. The reaction was then carried out for another hour at a temperature of 100°C to obtain an aqueous copolymer solution. The weight ratio of monomers in the copolymer in the solution was monomer I:II:III = 29:70:1. The copolymer in the solution was copolymer (A-1) (weight-average molecular weight 41,000).

[0075] <Manufacturing Example 2> Manufacturing of Polycarboxylic Acid Copolymer (A-2) 96 parts water and 53 parts polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added: 10) were charged into a glass reaction vessel equipped with a thermometer, stirrer, reflux apparatus, nitrogen inlet tube, and dropper. The reaction vessel was heated to 100°C under stirring. Subsequently, an aqueous monomer solution prepared by mixing 124 parts 2-hydroxypropyl acrylate and 82 parts water, and a mixture of 1 part ammonium persulfate and 39 parts water were continuously added dropwise to the reaction vessel, which was maintained at 100°C, over a period of 1 hour. The reaction was then carried out for another hour at a temperature of 100°C to obtain an aqueous copolymer solution. The weight ratio of monomers in the copolymer in the solution was monomer I:II:III = 30:70:0. The copolymer in the solution was copolymer (A-2) (weight-average molecular weight 63,000).

[0076] <Manufacturing Example 3> Manufacturing of Polycarboxylic Acid Copolymer (A-3) 159 parts of water and 26 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added: 10) were charged into a glass reaction vessel equipped with a thermometer, stirrer, reflux apparatus, nitrogen inlet tube, and dropper. The reaction vessel was heated to 100°C under stirring. Subsequently, an aqueous monomer solution prepared by mixing 124 parts of 2-hydroxypropyl acrylate and 82 parts of water, and a mixture of 1 part of ammonium persulfate and 39 parts of water were continuously added dropwise to the reaction vessel, which was maintained at 100°C, over a period of 1 hour. The reaction was then carried out for another hour at a temperature of 100°C to obtain an aqueous copolymer solution. The weight ratio of monomers in the copolymer in the solution was monomer I:II:III = 17:83:0. The copolymer in the solution was copolymer (A-3) (weight-average molecular weight 27,000).

[0077] <Manufacturing Example 4> Manufacturing of Polycarboxylic Acid Copolymer (A-4) 56 parts water and 53 parts polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added: 35) were charged into a glass reaction vessel equipped with a thermometer, stirrer, reflux apparatus, nitrogen inlet tube, and dropper. The reaction vessel was heated to 100°C under stirring. Subsequently, an aqueous monomer solution prepared by mixing 5 parts acrylic acid, 124 parts 2-hydroxypropyl acrylate, and 82 parts water, and a mixture of 1 part ammonium persulfate and 39 parts water were continuously added dropwise to the reaction vessel, which was maintained at 100°C, over 2 hours. The reaction was then allowed to proceed for 1 hour while maintaining the temperature at 100°C to obtain an aqueous copolymer solution. The weight ratio of monomers in the copolymer in the solution was monomer I:II:III = 29:68:3. The copolymer in the solution was copolymer (A-4) (weight-average molecular weight 183,000).

[0078] <Manufacturing Example 5> Manufacturing of Polycarboxylic Acid Copolymer (A-5) 291 parts water and 8 parts polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added: 10) were charged into a glass reaction vessel equipped with a thermometer, stirrer, reflux apparatus, nitrogen inlet tube, and dropper, and the reaction vessel was heated to 103°C under stirring. Subsequently, an aqueous monomer solution prepared by mixing 1 part acrylic acid, 36 parts 2-hydroxypropyl acrylate, 26 parts methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added: 25), and 39 parts water, and a mixture of 1 part ammonium persulfate and 39 parts water were continuously added dropwise to the reaction vessel, which was maintained at 100°C, over 2 hours. Furthermore, the reaction was allowed to proceed for 1 hour while maintaining the temperature at 100°C to obtain an aqueous copolymer solution. The weight ratio of monomers in the copolymer in the solution was monomer I:II:III = 11:51:38. The copolymer in the solution was copolymer (A-5) (weight-average molecular weight 23,000).

[0079] <Manufacturing Example 6> Manufacturing of Polycarboxylic Acid Copolymer (A-6) 84 parts of water were placed in a glass reaction vessel equipped with a thermometer, stirrer, reflux apparatus, nitrogen inlet tube, and dropper, and the temperature of the reaction vessel was raised to 101°C under stirring. Subsequently, an aqueous monomer solution prepared by mixing 156 parts of 2-hydroxypropyl acrylate and 104 parts of water, and a mixture of 1 part of ammonium persulfate and 49 parts of water were continuously added dropwise to the reaction vessel, which was maintained at 101°C, over 2 hours. Furthermore, the reaction was allowed to proceed for 1 hour while maintaining the temperature at 101°C to obtain an aqueous copolymer solution. The weight ratio of monomers in the copolymer in the solution was monomer I:II:III = 0:100:0. The copolymer in the solution was copolymer (A-6) (weight-average molecular weight 11,300).

[0080] <Manufacturing Example 7> Manufacturing of Polycarboxylic Acid Copolymer (A-7) 72 parts water and 169 parts polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added: 10) were charged into a glass reaction vessel equipped with a thermometer, stirrer, reflux apparatus, nitrogen inlet tube, and dropper. The reaction vessel was heated to 103°C under stirring. Subsequently, an aqueous monomer solution prepared by mixing 47 parts acrylic acid, 2 parts 31% sodium hydroxide aqueous solution, and 149 parts water, and a mixture of 1 part ammonium persulfate and 39 parts water were continuously added dropwise to the reaction vessel, which was maintained at 100°C, over 2 hours. The reaction was then allowed to proceed for 1 hour while maintaining the temperature at 100°C to obtain an aqueous copolymer solution. The weight ratio of monomers in the copolymer in the solution was monomer I:II:III = 81:0:19. The copolymer in the solution was copolymer (A-7) (weight-average molecular weight 16,500).

[0081] <(B) component> B-1: Glycerol (trivalent alcohol) • B-2: Ethylene glycol (divalent alcohol) B-3: Triethanolamine (trivalent alcohol) • B-4: Sodium gluconate (pentavalent alcohol, monovalent carboxylic acid)

[0082] <Dispersant> • Polycal: Polycarboxylic acid polymer (SF-500S manufactured by Frolic, Inc., a polycarboxylic acid polymer produced by polymerizing methoxypolyethylene glycol and methacrylic acid) • Lignin: Calcium lignin sulfonate (Sunflow RH, manufactured by Nippon Paper Industries Co., Ltd.) • Naphthalene: Naphthalene sulfonate formaldehyde condensate (Vaniol HDL-100, manufactured by Nippon Paper Industries Co., Ltd.)

[0083] <Examples 1-18 and Comparative Examples 1-10> Samples for Examples 1-18 and Comparative Examples 1-10 were prepared by using components A (A-1, A-2, A-3, A-4, A-5, A-6, A-7) and components B (B-1, B-2, B-3, B-4) in the combinations shown in Tables 2 and 4, and mixing each component with a spatula for about 30 seconds at ambient temperature (about 20°C).

[0084] <Mortar Test> Mortars (cement composition, hydraulic composition) containing samples from Examples 1-14 and Comparative Examples 1-7 were prepared according to the following procedure, and the resulting mortars were subjected to mortar flow tests and temperature rise evaluations under adiabatic temperature conditions.

[0085] <Mortar preparation method: Examples 1-14, Comparative Examples 1-7> At ambient temperature (20°C), sand (S) and cement (C) as shown in Table 1 were added and mixed for 10 seconds using a mortar mixer (Dalton universal mixing and stirring machine). Next, water, and the hydration heat inhibitors and dispersants shown in Table 2 were added in the amounts indicated in Table 2, and the mixture was mixed for another 120 seconds. After that, a portion of the mortar was discharged, and a fresh mortar test (slump test JIS R 5201 (measurement of the spread of fresh mortar as a flow value)) was performed to evaluate the fluidity of the mortar. Note that the hydration heat inhibitors, dispersants, and the water they contain were counted as part of the water in the mortar mixture.

[0086] <Adiabatic temperature test: Increase in temperature due to heat of hydration> Mixed mortar was filled into a 200 mL polyethylene disposable cup, a thermoelectric element was inserted into the center of the mortar, and the cup was placed inside a polystyrene foam container (15 cm thick). The temperature change of the mortar was then measured over time using a data logger. The highest temperature reached was defined as the highest temperature under adiabatic conditions. Table 2 shows the difference in maximum temperature compared to the highest temperature of mortar in Comparative Example 1, which did not use a hydration heat inhibitor.

[0087] [Table 1]

[0088] C: Mix the following two types of cement in equal weight. Ordinary Portland cement (manufactured by Ube Mitsubishi Cement Co., Ltd., specific gravity 3.16) Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation, specific gravity 3.16) W: Tap water (Iwakuni City, Yamaguchi Prefecture) S: Land sand from Kakegawa, Shizuoka Prefecture (fine aggregate, specific gravity 2.57) Heat of hydration inhibitor (solid content equivalent) See Table 2 Dispersant (based on solid content): See Table 2.

[0089] [Table 2]

[0090] In Table 2, the additive amount is the amount (in parts by weight) of each hydration heat inhibitor and each dispersant added per 100 parts by weight of cement. The total additive amount is the total amount (in parts by weight) of components (A) and (B) added per 100 parts by weight of cement. (B) / (A) is the weight ratio of component (B) to component (A).

[0091] The following is clear from Table 2. In Comparative Examples 2 to 7, the maximum temperature in the thermal insulation test was higher compared to the mortar of Comparative Example 1, whereas in each example, the increase in the maximum temperature was suppressed, and the mortar flow was appropriate compared to the mortar flow of the sample to which only the dispersant used in each example was added. Therefore, it has become clear that the hydration heat inhibitor for hydraulic compositions of the present invention can suppress hydration heat while maintaining the mortar flow within an appropriate range, that is, without significantly changing the physical properties such as fluidity and rheology of the hydraulic composition.

[0092] <Concrete Testing> Concrete (cement composition, hydraulic composition) was prepared by adding samples from Examples 15-18 and Comparative Examples 8-10 to base concrete according to the following procedure. The resulting concrete was subjected to concrete flow tests and temperature rise evaluations under adiabatic temperature conditions.

[0093] <Method for preparing base concrete: Comparative Example 8> At ambient temperature (20°C), cement (C), fine aggregate (S), and coarse aggregate (G) as shown in Table 3 were added and mixed for 10 seconds using a forced twin-screw mixer (Super Double Mixer, Taiheiyo Kiko Co., Ltd.). Next, water and the chemical admixtures (Ad) shown in Table 3 were added and mixed for 90 seconds. After that, a portion of the concrete was discharged, and a fresh concrete test (slump test JIS A 1101 (measurement of the spread of fresh concrete as a flow value)) was performed to evaluate the base concrete. The results are shown in Table 4.

[0094] <Preparation method for concrete with post-added hydration heat inhibitor: Examples 15-18 and Comparative Examples 9-10> To the base concrete prepared as described above, the hydration heat inhibitors listed in Table 4 were added, and the mixture was kneaded for 30 seconds in the forced twin-screw mixer described above. Immediately thereafter, the concrete was discharged, and a fresh concrete test was performed in the same manner as described above to evaluate the concrete with the hydration heat inhibitor added afterwards. The results are shown in Table 4.

[0095] <Increase in temperature due to heat of hydration> After evaluating the base concrete and the concrete with the added hydration heat inhibitor as described above, 40.0 kg (approximately 17.0 L) of each concrete was filled into a 20 L polyethylene bucket with a lid. A thermoelectric element was inserted into the center of the concrete, and the bucket was then placed inside a 100 L polyethylene bucket. The temperature change of the concrete was then measured over time using a data logger. The highest temperature reached during this process was defined as the highest temperature under adiabatic conditions. Table 4 shows the difference in maximum temperature compared to the highest concrete temperature of the base concrete (Comparative Example 8) without the hydration heat inhibitor.

[0096] [Table 3]

[0097] C: Mix the following three types of cement in equal weight. Ordinary Portland cement (manufactured by Ube Mitsubishi Cement Co., Ltd., specific gravity 3.16) Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation, specific gravity 3.16) Ordinary Portland cement (manufactured by Tokuyama Corporation, specific gravity 3.16) W: Tap water (Iwakuni City, Yamaguchi Prefecture) Ad: Chemical admixture (SV-10L, manufactured by Floric Co., Ltd.) S1: Limestone crushed sand from Tsukumi, Oita Prefecture (fine aggregate, specific gravity 2.67) S2: Land sand from Kakegawa, Shizuoka Prefecture (fine aggregate, specific gravity 2.56) G1: Crushed stone from Shunan, Yamaguchi Prefecture, 10mm size (coarse aggregate, specific gravity 2.77) G2: Crushed stone from Shunan, Yamaguchi Prefecture, 5mm size (coarse aggregate, specific gravity 2.72) Hydration heat inhibitors (addition rates listed in Table 4 are calculated on a solid content basis). See Table 4.

[0098] [Table 4]

[0099] In Table 4, the amount added is the amount (in parts by weight) of each hydration heat inhibitor added per 100 parts by weight of cement. The total amount added is the total amount (in parts by weight) of components (A) and (B) added per 100 parts by weight of cement. (B) / (A) is the weight ratio of component (B) to component (A).

[0100] As is clear from Table 4, the concrete in each example showed almost no change in slump flow after the addition of the hydration heat inhibitor compared to the base concrete in Comparative Example 8 without the hydration heat inhibitor. On the other hand, the concrete in Comparative Examples 9 and 10 showed a large change in slump flow, and the increased fluidity led to problems such as aggregate segregation, making it difficult to use in actual construction. Furthermore, in the concrete of each example, the maximum temperature in the adiabatic temperature test was lower compared to the base concrete in Comparative Example 8 without the addition of the hydration heat inhibitor, indicating that the temperature rise can be suppressed by adding this hydration heat inhibitor. This suggests that the temperature rise can be suppressed even in coarse concrete containing coarse aggregate, and that cracking due to thermal stress can be suppressed. On the other hand, no effect of suppressing the temperature rise was confirmed in the concrete of Comparative Examples 9 and 10. Therefore, it has become clear that the hydration heat inhibitor for hydraulic compositions of the present invention can suppress hydration heat without changing the slump flow from the base concrete, that is, without significantly changing the physical properties such as fluidity and rheology of the hydraulic composition.

Claims

1. A hydration heat inhibitor for hydraulic compositions, containing the following component (A). (A) Ingredients: A polycarboxylic acid copolymer or a salt thereof (a) obtained by copolymerizing 5 to 50% by weight of monomer (I) represented by the following general formula (1), 40 to 95% by weight of 2-hydroxypropyl acrylate monomer (II), and 0 to 40% by weight of other monomer (III) copolymerizable with monomers (I) to (II). R １－ O-(A １ O) ｎ１ -R ２ ・・・(1) (In the formula, R １ This represents an alkenyl group with 2 to 5 carbon atoms. １ O represents an oxyalkylene group having 2 to 18 carbon atoms, either identical or different. n1 is the average number of moles of oxyalkylene groups added, representing a number from 1 to 200. R ２ (This represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

2. A hydration heat inhibitor for hydraulic compositions according to claim 1, wherein the weight-average molecular weight of the polycarboxylic acid copolymer or its salt (a) is 5,000 to 300,000 in terms of polyethylene glycol.

3. (B) Component: Hydration heat inhibitor for hydraulic compositions according to claim 1 or 2, further comprising a hydroxyl group-containing compound.

4. The hydration heat inhibitor for hydraulic compositions according to claim 3, wherein the weight ratio (B) / (A) of the content of component (B) to the content of component (A) is 0.01 or more and 5.0 or less.

5. (B) The hydration heat inhibitor for hydraulic compositions according to claim 3 or 4, wherein component (B) comprises at least one selected from ethylene glycol and glycerol.

6. (C) Component: A hydration heat inhibitor for hydraulic compositions according to any one of claims 1 to 5, further comprising a dispersant other than components (A) and (B).

7. The hydration heat inhibitor for hydraulic compositions according to claim 6, wherein component (C) contains at least one selected from polycarboxylic acid polymers (excluding copolymers or their salts (a)), lignin sulfonic acid polymers, and naphthalene sulfonic acid polymers.

8. A hydration heat inhibitor for a hydraulic composition according to any one of claims 1 to 7, wherein the hydraulic composition is mass concrete.

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