JP2007099552A - Admixture for concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an admixture for concrete by which concrete excellent in the flowability retention is obtained even when the temperature of the concrete is at 35°C or higher and the elapsed time from the preparation is 60 minutes or longer. <P>SOLUTION: The admixture for concrete comprises a polymer A obtained by copolymerizing a specific monomer 1 such as an ethylenically unsaturated carboxylic acid derivative having a polyoxyalkylene group, a phosphoric monoester-based monomer 2 and a phosphoric diester-based monomer 3, and at least one kind of compounds B selected from the group consisting of an oxycarboxylic acid or its salts, saccharides and a suger-alcohol. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an admixture for concrete.

As a concrete admixture excellent in fluidity, a polycarboxylic acid-based admixture is known (Patent Document 1). In addition, a cement dispersant that prevents a decrease in fluidity with time (slump loss) at a high temperature exceeding 30 ° C. has been proposed (Patent Document 2). On the other hand, a cement dispersant having a phosphate group with excellent fluidity has been proposed (Patent Document 3).
JP-A-8-12396 JP 2002-167257 A JP 2000-327386 A

  However, when the concrete temperature is 30 ° C. or higher, particularly 35 ° C. or higher, and the elapsed time from preparation is 60 minutes or longer, the fluidity of the concrete is significantly reduced. Slump loss is a major issue.

  An object of the present invention is to provide a concrete admixture that can obtain a concrete having excellent fluidity retaining properties at a high temperature, for example, a concrete temperature of 35 ° C. or higher and an elapsed time from preparation of 60 minutes or longer. .

  The present invention includes a monomer 1 represented by the following general formula (1) [hereinafter referred to as monomer 1] and a monomer 2 represented by the following general formula (2) [hereinafter referred to as monomer 2]. And a monomer A [hereinafter referred to as monomer 2] represented by the following general formula (3), oxycarboxylic acid or a salt thereof, saccharide and sugar The present invention relates to a concrete admixture containing at least one compound B selected from the group consisting of alcohols (hereinafter referred to as compound B).

[Wherein R ¹ and R ² are each a hydrogen atom or a methyl group, R ³ is a hydrogen atom or — (CH ₂ ) q (CO) pO (AO) rR ⁴ , and AO is an oxyalkylene having 2 to 4 carbon atoms. Group or oxystyrene group, p is a number of 0 or 1, q is a number of 0 to 2, r is an average added mole number of AO, a number of 3 to 300, R ⁴ is a hydrogen atom or a carbon number of 1 to 18 Represents an alkyl group. ]

[Wherein R ¹¹ is a hydrogen atom or a methyl group, R ¹² is an alkylene group having 2 to 12 carbon atoms, m1 is a number of 1 to 30, M ³ and M ⁴ are a hydrogen atom, an alkali metal or an alkaline earth metal, respectively. Represents. ]

[Wherein R ¹³ and R ¹⁵ are each a hydrogen atom or a methyl group, R ¹⁴ and R ¹⁶ are each an alkylene group having 2 to 12 carbon atoms, m2 and m3 are each a number of 1 to 30 and M ⁵ is Represents a hydrogen atom, an alkali metal or an alkaline earth metal. ]

  According to the present invention, there is provided a concrete admixture capable of obtaining concrete having excellent fluidity retention even at a high temperature, for example, a concrete temperature of 35 ° C. or higher and an elapsed time from preparation of 60 minutes or longer.

<Polymer A>
The polymer A is represented by the monomer 1 represented by the above general formula (1), the monomer 2 represented by the above general formula (2), and the above general formula (3). This is a phosphate ester polymer obtained by copolymerizing the monomer 3.

[Monomer 1]
In monomer 1, R ¹ and R ² in general formula (1) are each a hydrogen atom or a methyl group. R ³ is a hydrogen atom or — (CH ₂ ) _q (CO) _p O (AO) _r R ⁴ , preferably a hydrogen atom. R ⁴ is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, preferably 1 to 12, more preferably 1 to 4, and further preferably 1 or 2, and particularly preferably a methyl group. When p is 0, AO forms an ether bond with (CH ₂ ) _q, and when p is 1, it forms an ester bond. q is 0 to 2, preferably 0 or 1, and more preferably 0. AO is an oxyalkylene group having 2 to 4 carbon atoms or an oxystyrene group, and AO is preferably an oxyalkylene group having 2 to 4 carbon atoms, more preferably an ethyleneoxy group (hereinafter referred to as EO group), and an EO group. Is 70 mol% or more, more preferably 80 mol% or more, and further preferably 90 mol% or more. r is the average added mole number of AO, is a number of 3 to 300, and is 3 to 300, preferably 4 to 120 in terms of the dispersibility of the polymer in the hydraulic composition and the effect of reducing the viscosity. More preferably, it is 4-80, More preferably, it is 4-50, Especially preferably, it is 4-30. Moreover, AO is different in an average of r repeating units, and random addition, block addition, or a mixture thereof may be included. For example, AO can contain a propyleneoxy group etc. besides EO group.

  Monomer 1 includes a half-terminated alkyl-capped polyalkylene glycol such as methoxypolyethylene glycol, methoxypolypropylene glycol, methoxypolybutylene glycol, methoxypolystyrene glycol, ethoxypolyethylenepolypropyleneglycol, (meth) acrylic acid, maleic acid (half ) Esterified products, etherified products with (meth) allyl alcohol, and (meth) acrylic acid, maleic acid, and (meth) allyl alcohol adducts having 2 to 4 carbon atoms are preferably used. In addition, (meth) acrylic acid means acrylic acid and / or methacrylic acid, and (meth) allyl means allyl and / or methallyl (the same applies hereinafter).

  More preferred is an esterified product of alkoxy, particularly methoxypolyethylene glycol and (meth) acrylic acid. Specific examples include ω-methoxypolyoxyalkylene methacrylate and ω-methoxypolyoxyalkylene acrylate, and ω-methoxypolyoxyalkylene methacrylate is more preferable.

  Monomer 1 used for production of polymer A can be obtained, for example, by esterification of alkoxypolyalkylene glycol and (meth) acrylic acid. From the viewpoint of the required addition amount and viscosity reduction when the esterified product is used in the concrete admixture of the present invention, the unreacted (meth) acrylic acid is 5% by weight based on the monomer 1 in terms of acid type. The following is preferable, 3% by weight or less is more preferable, 1.5% by weight or less is further preferable, and 1% by weight or less is more preferable. Examples of a method for reducing the amount of (meth) acrylic acid remaining during the production of the monomer 1 include topping, steaming, and solvent extraction.

[Monomer 2]
In the monomer (2), R ¹¹ is a hydrogen atom or a methyl group, and R ¹² is an alkylene group having 2 to 12 carbon atoms. m1 is a number from 1 to 30, and M ³ and M ⁴ are each a hydrogen atom, an alkali metal, or an alkaline earth metal. 1-20 are preferable, as for m1 in General formula (2), 1-10 are more preferable, and 1-5 are especially preferable.

  Specific examples include phosphoric acid monoesters of organic hydroxy compounds. Specific examples include polyalkylene glycol mono (meth) acrylate acid phosphates. For example, phosphoric acid mono-[(2-hydroxyethyl) methacrylic acid] ester, phosphoric acid mono-[(2-hydroxyethyl) acrylic acid ester] and the like can be mentioned. Among these, phosphoric acid mono-[(2-hydroxyethyl) methacrylic acid] ester is preferable from the viewpoint of ease of production and product quality stability. Further, alkali metal salts, alkaline earth metal salts, ammonium salts, alkylammonium salts and the like of these compounds may be used.

[Monomer 3]
In the monomer 3, in the general formula (3), R ¹³ and R ¹⁵ are each a hydrogen atom or a methyl group, and R ¹⁴ and R ¹⁶ are each an alkylene group having 2 to 12 carbon atoms. m2, m3 is a number of each 1 to 30, M ⁵ represents a hydrogen atom, an alkali metal or alkaline earth metal. M2 and m3 in the general formula (3) are each preferably 1 to 20, more preferably 1 to 10, and particularly preferably 1 to 5.

  Specific examples include phosphoric acid diesters of organic hydroxy compounds. Specific examples include polyalkylene glycol di (meth) acrylate acid phosphoric acid diester. Examples include phosphoric acid di-[(2-hydroxyethyl) methacrylic acid] ester, phosphoric acid di-[(2-hydroxyethyl) acrylic acid] ester, and the like. Among these, di-[(2-hydroxyethyl) methacrylic acid] ester phosphate is preferable from the viewpoint of ease of production and quality stability of the product. Further, alkali metal salts, alkaline earth metal salts, ammonium salts, alkylammonium salts and the like of these compounds may be used.

  Monomers 2 and 3 can be used as a mixed monomer including monomer 2 and monomer 3. Further, as the monomer 2 and the monomer 3, a phosphate ester obtained by reacting the organic hydroxy compound represented by the general formula (4) with a phosphorylating agent may be used.

  The mixed monomer including the monomer 2 and the monomer 3 is obtained as a reaction product by reacting, for example, an organic hydroxy compound represented by the general formula (4) and a phosphorylating agent at a predetermined charge ratio. It can also be manufactured.

[Wherein, R ²⁰ represents a hydrogen atom or a methyl group, R ²¹ represents an alkylene group having 2 to 12 carbon atoms, and m4 represents a number of 1 to 30. ]

  1-20 are preferable, as for m4 in General formula (4), 1-10 are more preferable, and 1-5 are especially preferable.

  Examples of the phosphorylating agent include orthophosphoric acid, phosphorus pentoxide (anhydrous phosphoric acid), polyphosphoric acid, phosphorus oxychloride and the like, and orthophosphoric acid and phosphorus pentoxide are preferable. These may be used alone or in combination of two or more. The amount of the phosphorylating agent in the reaction of the organic hydroxy compound and the phosphorylating agent can be appropriately determined according to the target phosphate ester composition.

  Examples of mixed monomers including monomer 2 and monomer 3 include mono-[(2-hydroxyethyl) methacrylic acid] phosphate and di-[(2-hydroxyethyl) methacrylic acid] phosphate. When the mixture is produced, it can be synthesized by a known technique (for example, JP-A-57-180618).

  As the mixed monomer including the monomer 2 and the monomer 3, a commercial product including a monoester and a diester can be used. For example, Phosmer M, Phosmer PE, Phosmer P (Unichemical) , JAMP514, JAMP514P, JMP100 (all Johoku Chemical), light ester P-1M, light acrylate P-1A (all Kyoeisha Chemical), MR200 (Daihachi Chemical), Kayamar (Nippon Kayaku), Ethyleneglycol methacrylate phosphate (Aldrich) Reagent).

  It has been confirmed that the above-mentioned commercial products and reaction products contain compounds other than the monoester (monomer 2) and diester (monomer 3). These other compounds are considered to be a mixture of polymerizable and non-polymerizable compounds, but in the present invention, such a mixture (mixed monomer) can be used as it is.

  The polymer A according to the present invention is a phosphate ester polymer obtained by copolymerizing the monomer 1, the monomer 2, and the monomer 3. It is also preferable to use a mixed monomer containing monomer 2 and monomer 3.

  In the copolymerization of the monomers, the molar ratio between the monomer 1 and the monomers 2 and 3 is as follows: monomer 1 / (monomer 2 + monomer 3) = 5/95 to 95/5, Furthermore, 10/90 to 90/10 are preferable. The molar ratio of monomer 1, monomer 2 and monomer 3 is as follows: monomer 1 / monomer 2 / monomer 3 = 5 to 95/3 to 90/1 to 80, and further 5 -96 / 3-80 / 1-60 (however, the total is 100) is preferable. In addition, about the monomer 2 and the monomer 3, the molar ratio and mol% shall be calculated based on an acid type compound (hereinafter the same).

  Moreover, in manufacture of the polymer A, it is preferable that the ratio of the monomer 3 shall be 1-60 mol%, and also 1-30 mol% in all the monomers used for reaction.

  The molar ratio of monomer 2 to monomer 3 is preferably monomer 2 / monomer 3 = 99/1 to 4/96, more preferably 99/1 to 5/95.

  From the viewpoint of suppressing gelation, the monomer solution containing monomer 2 and / or monomer 3 is preferably used for the reaction at a pH of 7 or less.

Hereinafter, more preferable production conditions will be described from the viewpoints of gelation suppression, adjustment of a suitable molecular weight, and performance design of a dispersant for hydraulic composition. From such a viewpoint, at the time of copolymerization, 4 mol% or more, further 6 mol% or more, particularly 8 mol% or more of the chain transfer agent is used with respect to the total number of moles of the monomers 1, 2 and 3. It is preferable. The upper limit of the amount of chain transfer agent used is preferably 100 mol% or less, more preferably 60 mol% or less, still more preferably 30 mol% or less, based on the total number of moles of monomers 1, 2 and 3. Most preferably, it can be 15 mol% or less. More specifically, (1) when r of monomer 1 is 3 to 30,
(1-1) When the total molar ratio of the monomers 1, 2 and 3 of the monomer 2 and the monomer 3 is 50 mol% or more, the chain transfer agent is the monomers 1, 2 and 3 It is preferable to use 6 to 100 mol%, particularly 8 to 60 mol%, based on the total of
(1-2) When the molar ratio in the sum of monomers 1, 2 and 3 of monomer 2 and monomer 3 is less than 50 mol%, the chain transfer agent is monomer 1, 2 and It is preferable to use 4 to 60 mol%, particularly 5 to 30 mol%, based on the total of 3.
(2) When r of monomer 1 used for polymer A is more than 30, the chain transfer agent is used in an amount of 6 to 50 mol%, particularly 8 to 40 mol%, based on monomers 1 to 3. Is preferred.

  The reaction rate of the monomers 2 and 3 is preferably 60% or more, more preferably 70% or more, more preferably 80% or more, more preferably 90% or more, and particularly preferably 95% or more. It can be selected from the viewpoint. Here, the reaction rate of the monomers 2 and 3 is calculated by the following equation.

In addition, the ratio (mol%) of the ethylenically unsaturated bond of the monomer 2 and the monomer 3 in the phosphorus-containing compound in the reaction system at the start and end of the reaction is measured by the following ¹ H-NMR. It can be calculated based on the result.
[ ¹ H-NMR conditions]
The polymer A dissolved in water and dried under reduced pressure is dissolved in deuterated methanol at a concentration of 3 to 4% by weight, and ¹ H-NMR is measured. The residual ratio of ethylenically unsaturated bonds is measured by an integral value of 5.5 to 6.2 ppm. In addition, the measurement of ¹ H-NMR uses “Mercury 400 NMR” manufactured by Varian, the number of data points is 42052, the measurement range is 6410.3 Hz, the pulse width is 4.5 μs, the pulse waiting time is 10 S, and the measurement temperature is 25.0 ° C. Perform under conditions.

  In the production of the polymer A, in addition to the monomers 1, 2, and 3, other monomers that can be copolymerized can also be used. Examples of other copolymerizable monomers include allyl sulfonic acid, methallyl sulfonic acid, any of these alkali metal salts, alkaline earth metal salts, ammonium salts, and amine salts. In addition, acrylic monomers such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and the like, and any one or more of alkali metal salts, alkalis Anhydrous compounds such as earth metal salts, ammonium salts, amine salts, methyl esters, ethyl esters and maleic anhydride may also be used. Furthermore, (meth) acrylamide, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2- (meth) acrylamide-2-metasulfonic acid, 2- (meth) acrylamide-2-ethanesulfonic acid, Examples include 2- (meth) acrylamide-2-propanesulfonic acid, styrene, styrenesulfonic acid and the like. The total proportion of monomers 1, 2, and 3 in all monomers is preferably 30 to 100 mol%, more preferably 50 to 100 mol%, particularly preferably 75 to 100 mol%, and more than 95 mol% to 100 Mole%, more preferably 97-100 mol% is preferred.

  In the production of the polymer A, monomers are preferably copolymerized in the presence of a predetermined amount of chain transfer agent. Moreover, you may use the other monomer, polymerization initiator, etc. which can be copolymerized.

  The reaction temperature of the monomers 1, 2 and 3 is preferably 40 to 100 ° C., more preferably 60 to 90 ° C., and the reaction pressure is 101.3 to 111.5 kPa (1 to 1.1 atm) in gauge pressure. 3-106.4 kPa (1-1.05 atm) is preferred.

  The pH of the reaction system can be adjusted with an inorganic acid (phosphoric acid, hydrochloric acid, nitric acid, sulfuric acid, etc.), NaOH, KOH, triethanolamine, or the like, if necessary.

  Here, the monomer solution containing the monomer 2 and / or the monomer 3 is preferably a water-containing system (that is, the solvent contains water) for pH measurement. May be measured by adding the required amount of water. From the viewpoint of uniformity of the monomer solution, prevention of gelation, and suppression of performance degradation, the pH is preferably 7 or less, more preferably 0.1 to 6, and further preferably 0.2 to 4.5. Monomer 1 is also preferably used as a monomer solution having a pH of 7 or less. This pH is at 20 ° C.

  In the present invention, the pH at 20 ° C. of the reaction solution collected during the reaction (from the start of the reaction to the end of the reaction) is defined as the pH during the reaction. It is preferable to start the reaction under conditions that clearly show that the pH during the reaction is 7 or less (monomer ratio, solvent, other components, etc.).

  When the reaction system is non-aqueous, it can be measured by adding an amount of water capable of measuring pH to the reaction system.

In the production method of the polymer A, the monomers 1, 2 and 3 are usually reacted under the consideration of other conditions if they are reacted under the conditions exemplified in the following (1) and (2). The pH inside is considered to be 7 or less.
(1) A monomer solution having a pH of 7 or less containing all of the monomers 1, 2 and 3 is used for the copolymerization reaction of the monomers 1, 2 and 3.
(2) The copolymerization reaction of the monomers 1, 2 and 3 is started at pH 7 or less. That is, the reaction is started after the reaction system containing the monomers 1, 2 and 3 is brought to pH 7 or lower.

[Chain transfer agent]
The chain transfer agent has a function of causing a chain transfer reaction in radical polymerization (a reaction in which a growing polymer radical reacts with another molecule to move a radical active site). It is a substance to be added.

  Examples of chain transfer agents include thiol chain transfer agents and halogenated hydrocarbon chain transfer agents, and thiol chain transfer agents are preferred.

As the thiol chain transfer agent, those having a —SH group are preferable, and in particular, the general formula HS—R—Eg (wherein R represents a hydrocarbon-derived group having 1 to 4 carbon atoms, and E is − OH, —COOM, —COOR ′ or —SO ₃ M group, M represents a hydrogen atom, monovalent metal, divalent metal, ammonium group or organic amine group, and R ′ represents an alkyl having 1 to 10 carbon atoms. In which g represents an integer of 1 to 2, for example, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, Examples include octyl thioglycolate, octyl 3-mercaptopropionate, and the like from the viewpoint of chain transfer effect in a copolymerization reaction including monomers 1 to 3. Mercaptoethanol are preferable, more preferably mercaptopropionic acid. These 1 type (s) or 2 or more types can be used.

  Examples of the halogenated hydrocarbon chain transfer agent include carbon tetrachloride and carbon tetrabromide.

  Examples of other chain transfer agents include α-methylstyrene dimer, terpinolene, α-terpinene, γ-terpinene, dipentene, 2-aminopropan-1-ol and the like. A chain transfer agent can use 1 type (s) or 2 or more types.

[Polymerization initiator]
In the production method of the polymer A, it is preferable to use a polymerization initiator, and in particular, the polymerization initiator is 5 mol% or more, further 7 to 50 mol% with respect to the total number of moles of the monomers 1, 2 and 3. In particular, it is preferable to use 10 to 30 mol%.

  Examples of aqueous polymerization initiators include ammonium persulfate salt or alkali metal salt, hydrogen peroxide, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis (2-methylpropionamide) dihydrate, etc. These water-soluble azo compounds can be used. In addition, an accelerator such as sodium bisulfite and an amine compound can be used in combination with the polymerization initiator.

[solvent]
The production of the polymer A can be carried out by a solution polymerization method, and the solvent used at that time contains water or water and methyl alcohol, ethyl alcohol, isopropyl alcohol acetone, methyl ethyl ketone or the like. Examples of the solvent include hydrous solvents. In view of handling and reaction equipment, water is preferred. In particular, when an aqueous solvent is used, the pH of the monomer solution containing the monomer 2 and / or the monomer 3 is preferably 7 or less, more preferably 0.1 to 6, particularly 0.2 to 4. A copolymerization reaction is preferably used for the reaction in terms of uniformity of the monomer mixture (handleability), monomer reaction rate, and suppression of crosslinking by hydrolysis of the pyro compound of the phosphoric acid compound.

  An example of the manufacturing method of the polymer A is shown. A predetermined amount of water is charged into a reaction vessel, the atmosphere is replaced with an inert gas such as nitrogen, and the temperature is raised. Prepare monomer 1, monomer 2, monomer 3, chain transfer agent mixed and dissolved in water, and polymerization initiator dissolved in water, and take 0.5 to 5 hours. Drip into the reaction vessel. At that time, each monomer, chain transfer agent and polymerization initiator may be dropped separately, or a mixed solution of monomers can be charged in a reaction vessel in advance and only the polymerization initiator can be dropped. is there. That is, the chain transfer agent, the polymerization initiator, and other additives may be added as an additive solution separately from the monomer solution, or may be added to the monomer solution after being added. From the viewpoint of stability, it is preferable to supply the reaction system as an additive solution separately from the monomer solution. In any case, the pH of the solution containing the monomer 2 and / or the monomer 3 is preferably 7 or less. Further, the copolymerization reaction is preferably performed with an acid agent or the like while maintaining the pH at 7 or less, and preferably aging is performed for a predetermined time. The polymerization initiator may be added dropwise at the same time as the monomer, or may be added in portions, but it is preferable to add in portions in terms of reducing unreacted monomers. For example, in the total amount of the polymerization initiator to be finally used, 1/2 to 2/3 polymerization initiator is added simultaneously with the monomer, and the remainder is aged for 1 to 2 hours after the completion of the monomer dropping, It is preferable to add. If necessary, it is further neutralized with an alkali agent (such as sodium hydroxide) after completion of ripening to obtain the phosphate ester polymer according to the present invention. This production example is suitable as a method for producing the polymer A according to the present invention.

  The total amount of monomers 1, 2 and 3 in the reaction system and other copolymerizable monomers is preferably 5 to 80% by weight, more preferably 10 to 65% by weight, and particularly preferably 20 to 50% by weight. .

  The polymer A preferably has a weight average molecular weight (Mw) of 10,000 to 150,000. This polymer A has a Mw of 10,000 or more, preferably 12,000 or more, more preferably 13,000 or more, more preferably 14,000 or more, from the viewpoint of the expression of the dispersion effect or the viscosity reduction effect. Particularly preferably, it is 15,000 or more, and it is 150,000 or less, preferably 130,000 or less, more preferably from the viewpoints of high molecular weight by crosslinking, suppression of gelation and performance in terms of dispersion effect and viscosity reduction effect. 120,000 or less, more preferably 110,000 or less, particularly preferably 100,000 or less, and from the viewpoints of both, preferably 12,000 to 130,000, more preferably 13,000 to 120,000, More preferably, it is 14,000-110,000, Most preferably, it is 15,000-100,000. It is preferable to have Mw in this range and Mw / Mn is 1.0 to 2.6. Here, Mn is a number average molecular weight.

Mw and Mn of the polymer A are measured by gel permeation chromatography (GPC) method under the following conditions.
[GPC conditions]
Column: G4000PWXL + G2500PWXL (Tosoh)
Eluent: 0.2M phosphate buffer / CH ₃ CN = 9/1
Flow rate: 1.0mL / min
Column temperature: 40 ° C
Detection: RI
Sample size: 0.2mg / mL
Reference material: Polyethylene glycol equivalent

  Further, in the chart pattern showing the molecular weight distribution obtained by the GPC method under the above conditions, the area having a molecular weight of 100,000 or more is 5% or less of the total area of the chart, so that dispersibility (required addition amount reduction) It is more preferable in terms of the viscosity reducing effect.

<Compound B>
Compound B works so as not to lower the fluidity imparting effect of the polymer A even when time elapses at a high temperature. Among the compounds B, the oxycarboxylic acid is preferably at least one selected from gluconic acid, glucoheptonic acid, arabonic acid, malic acid and citric acid. Examples of the salt of oxycarboxylic acid include sodium salts, potassium salts, calcium salts, magnesium salts, ammonium salts, organic salts such as triethanolamine salts, and inorganic salts. Of the compounds B, the saccharide is preferably at least one compound selected from monosaccharides, oligosaccharides and polysaccharides. Examples of monosaccharides include glucose, fructose, galactose, xylose, abitose, lipidose, and isomerized sugar. Examples of oligosaccharides include disaccharides and trisaccharides, and examples include saccharose, maltose, and dextrin. Moreover, the molasses containing these monosaccharides and oligosaccharides are mentioned. Among the compounds B, examples of the sugar alcohol include erythritol, arabitol, sorbitol, mannitol, dulcitol and the like, and sorbitol is preferable.

  As compound B, oxycarboxylic acid or a salt thereof and saccharide are preferable, saccharide is particularly preferable, and saccharose is more preferable. Under severe conditions where the concrete temperature exceeds 35 ° C., monosaccharides such as glucose, disaccharides such as saccharose, oxycarboxylic acids such as gluconic acid or salts thereof are preferred, and saccharose is particularly preferred.

<Concrete admixture>
The concrete admixture of the present invention contains polymer A and compound B. The blending ratio can be arbitrarily adjusted depending on the purpose of use, but from the viewpoint of fluidity expression and fluidity retention at 35 ° C. or higher, the weight ratio of polymer A to compound B (polymer A / compound B) is polymer A / Compound B = 100/1 to 100/50 is preferable, 100/3 to 100/40 is more preferable, and 100/3 to 100/30 is particularly preferable.

  The concrete admixture of the present invention can be obtained, for example, by mixing an aqueous solution containing the polymer A and an aqueous solution containing the compound B. From the viewpoint of workability, it is preferably liquid.

  The concrete admixture of the present invention is 0.01 to 5 parts by weight in terms of solid concentration, preferably the total solid concentration of polymer A and compound B, relative to 100 parts by weight of hydraulic powder, particularly cement. It is preferably used in a ratio of 0.05 to 2 parts by weight in terms of fluidity expression and fluidity retention at 35 ° C. or higher.

  The concrete admixture of the present invention is a polymer C obtained by copolymerizing the monomer 1 represented by the general formula (1) and the monomer 5 represented by the following general formula (5). Can be contained.

Wherein, R ⁵ to R ⁷ are each a hydrogen atom, a methyl group or ^{_{(CH 2) s COOM 2,}} (CH 2) s COOM 2 is COOM ¹ or another (CH _{²⁾ s} COOM ₂ and anhydrous In this case, M ¹ and M ² of those groups are not present. s represents the number of 0-2. M ¹ and M ² each represent a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkyl ammonium group, a substituted alkyl ammonium group, an alkyl group, a hydroxyalkyl group, or an alkenyl group. ]

[Monomer 1]
To obtain a polymer C, and the monomer 1, R ^1, R ² in the formula (1) are each a hydrogen atom or a methyl group. R ³ is a hydrogen atom or — (CH ₂ ) _q (CO) _p O (AO) _r R ⁴ , preferably a hydrogen atom. R ⁴ is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, preferably 1 to 12, more preferably 1 to 4, and further preferably 1 or 2, and particularly preferably a methyl group. When p is 0, AO forms an ether bond with (CH ₂ ) _q, and when p is 1, it forms an ester bond. q is 0 to 2, preferably 0 or 1, and more preferably 0. AO is an oxyalkylene group having 2 to 4 carbon atoms or an oxystyrene group, and AO is preferably an oxyalkylene group having 2 to 4 carbon atoms, more preferably an ethyleneoxy group (hereinafter referred to as EO group), and an EO group. Is 70 mol% or more, more preferably 80 mol% or more, and further preferably 90 mol% or more. r is the average added mole number of AO, and is a number of 3 to 300, preferably 5 to 120. Moreover, AO is different in an average of r repeating units, and random addition, block addition, or a mixture thereof may be included. For example, AO can contain a propyleneoxy group etc. besides EO group.

  In order for the polymer C to express the initial strength and fluidity of the concrete higher, r in the general formula (1) is preferably 50 to 300, more preferably 110 to 300, and r is 200 or less from the viewpoint of polymerizability. Since 150 or less, especially 130 or less are preferable, from a comprehensive viewpoint, r is preferably 110 to 200, more preferably 110 to 150, and particularly preferably 110 to 130. From the viewpoint of further reducing the viscosity of the concrete, r in the general formula (1) is preferably 3 to 100, and more preferably 3 to 50.

  Monomer 1 includes a half-terminated alkyl-capped polyalkylene glycol such as methoxypolyethylene glycol, methoxypolypropylene glycol, methoxypolybutylene glycol, methoxypolystyrene glycol, ethoxypolyethylenepolypropyleneglycol, (meth) acrylic acid, maleic acid (half ) Esterified products, etherified products with (meth) allyl alcohol, and (meth) acrylic acid, maleic acid, and (meth) allyl alcohol adducts having 2 to 4 carbon atoms are preferably used.

  More preferred is an esterified product of alkoxy, particularly methoxypolyethylene glycol and (meth) acrylic acid. Specific examples include ω-methoxypolyoxyalkylene methacrylate and ω-methoxypolyoxyalkylene acrylate, and ω-methoxypolyoxyalkylene methacrylate is more preferable.

When the polymer C is obtained using a plurality of monomers 1 having different r, r represents an average value of the whole polymer. For example, when the polymer C is obtained using x ₁ mol% of a monomer where r = r ₁ and x ₂ mol% of a monomer where r = r ₂ , r is r = (r ₁ x ₁ + r ₂ x ₂ ) / (x ₁ + x ₂ ).

[Monomer 5]
In the monomer 5, R ^{5 to} R ⁷ in the general formula (5) are each a hydrogen atom, a methyl group, or (CH ₂ ) _s COOM ² , and (CH ₂ ) _s COOM ² is COOM ¹ or other (CH ₂ ) _s COOM ² and an anhydride may be formed. In that case, M ¹ and M ² of those groups do not exist. s represents the number of 0-2. R ⁵ is preferably a hydrogen atom, and R ⁶ is preferably a methyl group. R ⁷ is preferably a hydrogen atom or (CH ₂ ) _s COOM ² .

M ¹ and M ² are each a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group, a substituted alkylammonium group, an alkyl group, a hydroxyalkyl group, or an alkenyl group. M ¹ and M ² are each preferably a hydrogen atom or an alkali metal.

  Specifically, monocarboxylic acid monomers such as (meth) acrylic acid and crotonic acid, dicarboxylic acid monomers such as maleic acid, itaconic acid and fumaric acid, or anhydrides or salts thereof (for example, alkalis) Metal salt, alkaline earth metal salt, ammonium salt, mono-, di-, trialkyl (carbon number 2 to 8) ammonium salt optionally substituted with hydroxyl group) or ester, preferably (meth) acrylic acid, Maleic acid, maleic anhydride, more preferably (meth) acrylic acid or an alkali metal salt thereof.

  Polymer C is prepared by, for example, charging water in a reaction vessel and raising the temperature, and reacting monomer 1 and monomer 5 in the presence of a chain transfer agent or the like at a constant molar ratio and weight ratio. Can be manufactured. Neutralize after aging if necessary.

  The weight ratio (monomer 1 / monomer 5) of monomer 1 and monomer 5 used for the production of polymer C is preferably 97/3 to 3/97, more preferably 95/5 to 5/95. 90/10 to 10/90 is more preferable.

The polymer C preferably has an average weight ratio (Y _I ) of the monomer 5 to all monomers for producing the polymer of 1 to 30 (% by weight). The average weight ratio is represented by [total amount of monomer 5 / total amount of all monomers used for the synthesis of polymer C] × 100 (% by weight). In order to broaden the versatility of the polymer C, it is preferable to use a polymer C ′ produced with an average weight ratio (Y _II ) different from the average weight ratio of the polymer C in combination.

The polymers C and C ′ are preferably selected so that the average weight ratio (Y _I ) and (Y _II ) differ by 2 or more. The polymers C and C ′ may be the same or different in the types of the monomer 1 and the monomer 5 used in the production, but it is preferable to use the same type.

  In the present invention, the polymer B is obtained by copolymerizing at least one monomer 1 and at least one monomer 5 and is a mole of the monomer 1 and the monomer 5. It is also possible to use a copolymer mixture in which the ratio [monomer 1] / [monomer 5] is changed at least once during the reaction. Such a copolymer mixture is obtained by changing the molar ratio [monomer 1] / [monomer 5] of monomer 1 and monomer 5 added to the reaction system at least once during the reaction. Can be manufactured. In that case, it is preferable that the difference between the maximum value and the minimum value of the molar ratio [monomer 1] / [monomer 5] is at least 0.05, particularly 0.05 to 2.5.

  When the polymer C is used, the weight ratio of the polymer A to the polymer C is polymer A / polymer C = 99/1 to 20/80, more preferably 95/5 to 30/70, and particularly 90/10 to 10. 50/50 is preferred.

  The concrete admixture of the present invention can also contain other additives (materials). For example, resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, alkylbenzene sulfonic acid (salt), alkane sulfonate, polyoxyalkylene alkyl (phenyl) ether, polyoxyalkylene alkyl (phenyl) ether sulfate (salt) ), Polyoxyalkylene alkyl (phenyl) ether phosphate (salt), protein material, AE agent such as alkenyl succinic acid, α-olefin sulfonate; foaming agent; thickener; silica sand; AE water reducing agent; calcium chloride, Soluble calcium salts such as calcium nitrite, calcium nitrate, calcium bromide and calcium iodide, chlorides such as iron chloride and magnesium chloride, sulfate, potassium hydroxide, sodium hydroxide, carbonate, thiosulfate, formic acid (Salt), a Fastening agents or accelerators such as canolamine; foaming agents; waterproofing agents such as resin acids (salts), fatty acid esters, oils and fats, silicones, paraffins, asphalts, waxes; blast furnace slag; fluidizing agents; dimethylpolysiloxanes, polyalkylenes Antifoaming agents such as glycol fatty acid esters, mineral oils, fats and oils, oxyalkylenes, alcohols and amides; antifoaming agents; fly ash; melamine sulfonic acid formalin condensates, aminosulfonic acids, polymaleic acid, etc. High-performance water reducing agent; Silica fume; Anticorrosive agent such as nitrite, phosphate, zinc oxide; EO adduct of polyacrylic acid amide, polyethylene glycol, oleyl alcohol or reaction product of this with vinylcyclohexene diepoxide, etc. Water-soluble polymers such as synthetic systems; Polymers such as alkyl (meth) acrylates Marujon is mentioned. In the total solid content of the concrete admixture of the present invention, the total concentration of the polymer A and the compound B is preferably 50 to 100% by weight, and more preferably 80 to 100% by weight.

<Concrete>
The concrete that is the target of the admixture of the present invention is a hydraulic composition containing hydraulic powder, and the hydraulic powder is a powder having physical properties that hardens by a hydration reaction. And gypsum. Preferred are ordinary Portland cement, Belite cement, medium heat cement, early strong cement, super early strong cement, sulfate resistant cement, etc., and blast furnace slag, fly ash, silica fume, stone powder (calcium carbonate powder), etc. May be added. In addition, the hydraulic composition finally obtained by adding sand, sand and gravel as aggregates to these powders is generally called mortar, concrete, etc., respectively. The admixture of the present invention is not only for ready-mixed concrete and concrete vibration products, but also for self-leveling, for refractories, for plaster, for gypsum slurry, for lightweight or heavy concrete, for AE, for repair, for prepacked, for trayy, It is useful in any field of various concrete such as grout, ground improvement, and cold.

  The concrete has a water / hydraulic powder ratio [weight percentage (% by weight) of water and hydraulic powder in the slurry, usually abbreviated as W / P. Abbreviated. It can be 65% by weight or less, further 10 to 60% by weight, further 12 to 57% by weight, further 15 to 55% by weight, especially 20 to 55% by weight. In particular, the effect of the admixture of the present invention is remarkably exhibited even at a blending ratio of 30 to 50% by weight.

Production Example A1
366 g of water was charged into a glass reaction vessel (four-necked flask) equipped with a stirrer, and was purged with nitrogen while stirring, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. 450 g of ω-methoxypolyethyleneglycol monomethacrylate (average added mole number of ethylene oxide 23) (effective part 60.8% by weight, moisture 35% by weight), phosphoric acid mono-[(2-hydroxyethyl) methacrylic acid] ester and phosphorus A mixture of 71.6 g of phosphoric acid ester (A), which is a mixture of acid di-[(2-hydroxyethyl) methacrylic acid] ester and 4.5 g of 3-mercaptopropionic acid, and 8.4 g of ammonium persulfate in water Two of those dissolved in 48 g were added dropwise over 1.5 hours. After aging for 1 hour, 1.8 g of ammonium persulfate dissolved in 10 g of water was added dropwise over 30 minutes, and then aging was carried out at the same temperature (80 ° C.) for 1.5 hours. After completion of aging, the mixture was neutralized with 44.4 g of a 32% aqueous sodium hydroxide solution to obtain a polymer a-1 having a weight average molecular weight of 35,000. (Monomer polymerization pH: 1.0, reaction rate 100%)

The phosphoric acid ester (A) used in this production example was prepared by charging 200 g of 2-hydroxyethyl methacrylate and 36.0 g of 85% phosphoric acid (H ₃ PO ₄ ) in a reaction vessel. Phosphoric acid) (P ₂ O ₅ ) 89.1 g was gradually added while cooling so that the temperature did not exceed 60 ° C. After completion, the reaction temperature was set to 80 ° C., reacted for 6 hours, and cooled. This phosphate esterified product (A) was also used in some of the following production examples.

Production Example A2
371 g of water was charged into a glass reaction vessel with a stirrer (four-necked flask), purged with nitrogen while stirring, and heated to 80 ° C. in a nitrogen atmosphere. 500 g of ω-methoxypolyethyleneglycol monomethacrylate (average added mole number of ethylene oxide 23) (effective part 60.8% by weight, moisture 35% by weight), phosphoric acid mono-[(2-hydroxyethyl) methacrylic acid] ester and phosphorus A mixture of 34.1 g of phosphoric acid ester (A), which is a mixture of acid di-[(2-hydroxyethyl) methacrylic acid] ester and 2.8 g of 3-mercaptopropionic acid, and 7.2 g of ammonium persulfate in water Two of those dissolved in 41 g were added dropwise over 1.5 hours. After aging for 1 hour, 1.6 g of ammonium persulfate dissolved in 9 g of water was added dropwise over 30 minutes, and then aging was carried out at the same temperature (80 ° C.) for 1.5 hours. After completion of the aging, the mixture was neutralized with 21.2 g of a 32% aqueous sodium hydroxide solution to obtain a polymer a-2 having a weight average molecular weight of 34,000. (Monomer polymerization pH: 1.1, reaction rate 100%)

Production Example A3
A glass reaction vessel (four-necked flask) with a stirrer was charged with 381 g of water, purged with nitrogen while stirring, and heated to 80 ° C. in a nitrogen atmosphere. 520 g of ω-methoxypolyethyleneglycol monomethacrylate (average addition mole number of ethylene oxide 23) (effective part 60.8% by weight, moisture 35% by weight), mono-[(2-hydroxyethyl) methacrylic acid] phosphate and phosphorus A mixture of 28.6 g of phosphoric acid ester (A) which is a mixture of acid di-[(2-hydroxyethyl) methacrylic acid] ester and 2.8 g of 3-mercaptopropionic acid, and 7.2 g of ammonium persulfate in water Two of those dissolved in 41 g were added dropwise over 1.5 hours. After aging for 1 hour, 1.6 g of ammonium persulfate dissolved in 9 g of water was added dropwise over 30 minutes, and then aging was carried out at the same temperature (80 ° C.) for 1.5 hours. After completion of aging, the mixture was neutralized with 17.7 g of a 32% aqueous sodium hydroxide solution to obtain a polymer a-3 having a weight average molecular weight of 36000. (Monomer polymerization pH: 1.1, reaction rate 100%)

Production Example A4
A glass reaction vessel (four-necked flask) equipped with a stirrer was charged with 471 g of water, purged with nitrogen while stirring, and heated to 80 ° C. in a nitrogen atmosphere. 290 g of ω-methoxypolyethyleneglycol monomethacrylate (average addition mole number of ethylene oxide 9) (effective content 84.4% by weight, moisture 10% by weight), phosphoric acid mono-[(2-hydroxyethyl) methacrylic acid] ester and phosphorus A mixture of 93.8 g of phosphoric acid ester (A), which is a mixture of acid di-[(2-hydroxyethyl) methacrylic acid] ester and 11.3 g of 3-mercaptopropionic acid, and 8.2 g of ammonium persulfate in water Two of those dissolved in 46 g were added dropwise over 1.5 hours. After aging for 1 hour, a solution prepared by dissolving 3.3 g of ammonium persulfate in 19 g of water was dropped over 30 minutes, and then aging was performed at the same temperature (80 ° C.) for 1.5 hours. After completion of aging, the solution was neutralized with 58.2 g of a 32% aqueous sodium hydroxide solution to obtain a polymer a-4 having a weight average molecular weight of 25,000. (Monomer polymerization pH: 1.0, reaction rate 99%)

Production Example A5
489 g of water was charged into a glass reaction vessel (four-necked flask) equipped with a stirrer, purged with nitrogen while stirring, and heated to 80 ° C. in a nitrogen atmosphere. 290 g of ω-methoxypolyethyleneglycol monomethacrylate (average addition mole number of ethylene oxide 9) (effective content 84.4% by weight, moisture 10% by weight), phosphoric acid mono-[(2-hydroxyethyl) methacrylic acid] ester and phosphorus A mixture of 53.2 g of phosphoric acid ester (A) which is a mixture of acid di-[(2-hydroxyethyl) methacrylic acid] ester and 9.1 g of 3-mercaptopropionic acid and 7.8 g of ammonium persulfate in water Two of those dissolved in 44 g were added dropwise over 1.5 hours. After aging for 1 hour, a solution prepared by dissolving 3.1 g of ammonium persulfate in 18 g of water was dropped over 30 minutes, and then aging was performed at the same temperature (80 ° C.) for 1.5 hours. After completion of aging, the mixture was neutralized with 33.0 g of a 32% aqueous sodium hydroxide solution to obtain a polymer a-5 having a weight average molecular weight of 21,000. (Monomer polymerization pH: 1.1, reaction rate 98%)

Production Example A6
A glass reaction vessel (four-necked flask) with a stirrer was charged with 189 g of water, purged with nitrogen while stirring, and heated to 80 ° C. in a nitrogen atmosphere. 40 g of ω-methoxypolyethylene glycol monomethacrylate (addition mole number of ethylene oxide 9: NK ester M90G manufactured by Shin-Nakamura Chemical Co., Ltd.), mono-[(2-hydroxyethyl) methacrylic acid] phosphate and di-[(2- Hydroxyethyl) methacrylic acid] ester mixture (Fosmer M: Unichemical Co., Ltd.) 43.8 g and 3-mercaptopropionic acid 1.6 g in water 40 g and ammonium persulfate 5.4 g in water 62 g Two of the dissolved ones were added dropwise over 1.5 hours. After aging for 1 hour, 2.7 g of ammonium persulfate dissolved in 31 g of water was added dropwise over 30 minutes, and then aging was performed at the same temperature (80 ° C.) for 1.5 hours. After completion of aging, the mixture was neutralized with 54.4 g of a 20% aqueous sodium hydroxide solution to obtain a polymer a-6 having a weight average molecular weight of 51,000. (Monomer polymerization pH: 1.1, reaction rate 100%)

Production Example A7
A glass reaction vessel (four-necked flask) with a stirrer was charged with 218 g of water, purged with nitrogen while stirring, and heated to 80 ° C. in a nitrogen atmosphere. 55 g of ω-methoxypolyethylene glycol monomethacrylate (addition mole number of ethylene oxide 23: NK ester M230G manufactured by Shin-Nakamura Chemical Co., Ltd.), mono-[(2-hydroxyethyl) methacrylic acid] phosphate and di-[(2- Hydroxyethyl) methacrylic acid] ester mixture (Fosmer M: Unichemical Co., Ltd.) 32.3 g and 3-mercaptopropionic acid 1.1 g dissolved in water 55 g and ammonium persulfate 3.8 g in water 43 g Two of the dissolved ones were added dropwise over 1.5 hours. After aging for 1 hour, 1.9 g of ammonium persulfate dissolved in 22 g of water was added dropwise over 30 minutes, and then aging was performed at the same temperature (80 ° C.) for 1.5 hours. After completion of aging, the mixture was neutralized with 40.1 g of a 20% aqueous sodium hydroxide solution to obtain a polymer a-7 having a weight average molecular weight of 51,000. (Monomer polymerization pH: 1.3, reaction rate 100%)

Production Example C1
A glass reaction vessel with a stirrer (four-necked flask) was charged with 281.4 g of water, purged with nitrogen while stirring, and heated to 80 ° C. in a nitrogen atmosphere. ω-methoxypolyethyleneglycol methacrylate (added mole number of ethylene oxide 120) 336.5g, methacrylic acid 22.2g and 2-mercaptoethanol 1.89g dissolved in water 238.2g, and ammonium persulfate 3.68g dissolved in water 45g The two were added dropwise over 1.5 hours each. Subsequently, 1.47 g of ammonium persulfate dissolved in 15 g of water was added dropwise over 30 minutes, and then aging was performed at the same temperature (80 ° C.) for 1 hour. After completion of aging, the mixture was neutralized with 18.7 g of 48% sodium hydroxide to obtain a copolymer c-1. (Weight average molecular weight 79000)

Production Example C2
A glass reaction vessel with a stirrer (four-necked flask) was charged with 246.4 g of water, purged with nitrogen while stirring, and heated to 56 ° C. in a nitrogen atmosphere. The mixture of 148.8 g of ω-methoxypolyethyleneglycol methacrylate (ethylene oxide addition mole number 10), 39.2 g of methacrylic acid and 2.32 g of 3-mercaptopropionic acid and 43.3 g of 5% aqueous solution of ammonium persulfate for 1.5 hours each It was dripped over. Thereafter, aging was performed at the same temperature (56 ° C.) for 3 hours. After completion of aging, the mixture was neutralized with 48% sodium hydroxide to pH = 6 to obtain a copolymer c-2. (Molecular weight 34000)

  Table 1 shows Compound B used in the following Examples and Comparative Examples.

  Concrete admixtures were prepared using the above polymer A, compound B, and other copolymers, and evaluated when used on concrete having the composition shown in Table 2. The results are shown in Table 3.

The materials used in Table 2 are as follows.
W (Wed): Tap water (Wakayama Kinokawa Waterworks)
C (cement): normal Portland cement, density = 3.16
S1 (fine aggregate): land sand from Hasaki, Kashima-gun, Ibaraki, density = 2.60
S2 (fine aggregate): Crushed sand from Tomuro-cho, Sano City, Ibaraki Prefecture, density = 2.60
G (Coarse aggregate): Crushed stone from Tomuro-cho, Sano City, Ibaraki Prefecture, density = 2.65

(Performance evaluation)
In an environmental chamber at 35 ° C, add 30 liters of concrete blended material into a forced biaxial mixer (50 liters), knead for 90 seconds, and add admixture so that the concrete slump immediately after discharge is 22-24 cm. The amount was adjusted (concrete temperature, 35 ° C.). The slump value was measured every 30 minutes immediately after kneading and after 90 minutes, and the slump retention rate with respect to the slump value immediately after kneading was calculated. The results are shown in Table 3. The slump value was measured according to JIS-A1101.

  In Table 3, the addition amount is the weight percent of cement as an effective component of the sum of the polymers (polymers A and C, some compounds B) and compound B.

Claims (5)

Monomer 1 represented by the following general formula (1), monomer 2 represented by the following general formula (2), and monomer 3 represented by the following general formula (3) are copolymerized A concrete admixture containing the polymer A obtained in this manner and one or more compounds B selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols.

[Wherein R ¹ and R ² are each a hydrogen atom or a methyl group, R ³ is a hydrogen atom or — (CH ₂ ) q (CO) pO (AO) rR ⁴ , and AO is an oxyalkylene having 2 to 4 carbon atoms. Group or oxystyrene group, p is a number of 0 or 1, q is a number of 0 to 2, r is an average added mole number of AO, a number of 3 to 300, R ⁴ is a hydrogen atom or a carbon number of 1 to 18 Represents an alkyl group. ]

[Wherein R ¹¹ is a hydrogen atom or a methyl group, R ¹² is an alkylene group having 2 to 12 carbon atoms, m1 is a number of 1 to 30, M ³ and M ⁴ are a hydrogen atom, an alkali metal or an alkaline earth metal, respectively. Represents. ]

[Wherein R ¹³ and R ¹⁵ are each a hydrogen atom or a methyl group, R ¹⁴ and R ¹⁶ are each an alkylene group having 2 to 12 carbon atoms, m2 and m3 are each a number of 1 to 30 and M ⁵ is Represents a hydrogen atom, an alkali metal or an alkaline earth metal. ] The concrete admixture according to claim 1, wherein the compound B is a monosaccharide or a disaccharide. The admixture for concrete according to claim 1 or 2, wherein the weight ratio of the polymer A to the compound B (polymer A / compound B) is 100/1 to 100/50.   The admixture for concrete according to any one of claims 1 to 3, wherein the polymer A is obtained by copolymerizing the monomers 1 to 3 at a pH of 7 or less.   The concrete admixture according to any one of claims 1 to 4, wherein the polymer A is obtained by copolymerizing the monomers 1 to 3 in the presence of a chain transfer agent.