JPH0812399A - Admixture composition for concrete product - Google Patents

Abstract

PURPOSE:To lower concrete viscosity, to decrease surface bubbles and to improve compaction by allowing an admixture composition to consist of a copolymer obtained by polymerizing a specific monomer and a monomer selected between two kinds of compounds and a defoaming agent. CONSTITUTION:A copolymer A having the weight-average molecular weight of 3000-1000000 is obtained by polymerizing the monomer (a) expressed by formula I and one or more kinds of the monomers selected from the compounds expressed by formulas II and III in the mol ratio of (a)/(b)=0.1/100-100/100. The copolymer A and the defoaming agent B such as dimethyl polysiloxane are blended in the ratio (weight ratio of solid matter) of A/B=100/0.01-5.0. In the formula I, each of R1 and R2 is hydrogen or methyl, m1 is 0-2, AO is a 2-3C oxyalkylene, (n) is 110-300, X is H or a 1-3C alkyl. In the formulas II and III, each of R3-R5 is H, methyl or (CH2)m2COOM2, R6 is H or methyl, each of M1, M2 and Y is H, an alkali metal, alkaline earth metal, ammonium, an alkylammonium or a substituted alkyl ammonium and m2 is 0-2.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an admixture composition for concrete products. More specifically, it is used as a concrete admixture used in the production of secondary concrete products, and in the production of compacted products by the reduction of bubbles generated on the surface of vibration compacted products and high-fluidity filled concrete products and centrifugal force, The present invention relates to an admixture composition capable of improving compaction property and shortening molding time.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
Concrete products include a vibrating product that is compacted by an internal or external vibrator after being poured into a concrete formwork, and a centrifugal product that is compacted by centrifugal force, such as piles, poles, and fume tubes.

The concrete used in these products has a high performance water reducing agent such as a naphthalene type (naphthalene sulfonic acid formaldehyde condensate) in order to secure strength.
), Melamine-based (melamine sulfonic acid formaldehyde condensate) and other admixtures are essential.

However, although concrete having a high-performance water-reducing agent can exhibit a certain fluidity (slump value), the viscosity of the concrete increases and the compaction tends to decrease.

Therefore, in the vibrating product, the air bubbles contained in the concrete and the air bubbles entrained at the time of filling cannot be defoamed and remain, and the appearance of the surface of the hardened concrete is remarkably poor. Further, the centrifugal product requires a long time for compaction, which lowers productivity.

From these things, as an admixture composition,
Admixtures that reduce the viscosity of concrete without damaging the water reducing agent are desired.

[0007]

As a result of earnest research, the inventors of the present invention have found that a skeleton of a dispersant having an alkylene oxide having a high water-retaining property is effective in reducing the viscosity of concrete, and the alkylene oxide has a viscosity of 110 to 300. It has been found to be extremely effective at high added mole numbers in the molar range. Furthermore, by using a dispersant composition containing an antifoaming agent,
By reducing friction between concrete materials and suppressing entrainment of bubbles, it is possible to reduce surface bubbles and improve compaction.

That is, the present invention is one selected from a monomer (a) represented by the following general formula (A) and a compound represented by the following general formulas (B) and (C). The present invention relates to an admixture composition for concrete products, which comprises a copolymer (a) obtained by polymerizing the above monomer (b) and an antifoaming agent (b) as essential components.

[0009]

Embedded image

(Wherein R ₁ and R _{2 are} hydrogen and a methyl group m ₁ is an integer of 0 to 2 AO is an oxyalkylene group having a carbon number of 2 to 3 n is an integer of 110 to 300 X is hydrogen or a carbon number of 1 ~ Represents an alkyl group of 3).

[0011]

[Chemical 4]

(In the formula, R _{3 to} R ₅ : hydrogen, methyl group, (C
H ₂ ) m ₂ COOM ₂ R ₆ : hydrogen, methyl group M ₁ , M ₂ , Y: hydrogen, alkali metal, alkaline earth metal, ammonium, alkylammonium or substituted alkylammonium m ₂ : represents an integer of 0 to 2 . ) Copolymer used in the present invention (a) Copolymer of a polyalkylene glycol monoester monomer having an unsaturated bond having a similar structure to an acrylic acid-based and / or unsaturated dicarboxylic acid-based monomer Known classes of patents (Japanese Patent Publication No. 59-18338, Japanese Patent Publication No. 2-78978, Japanese Patent Publication No. 2-7898, Japanese Patent Publication No.
2-7901, JP-B2-11542, JP-A-3-75252, JP-A-59-1
62163). However, even when using a polycarboxylic acid salt having these alkylene chains as an admixture composition for concrete products, the decrease in the viscosity of concrete is not sufficient,
Moreover, since the air bubble entrainment is large, the compaction property cannot be improved and the surface air bubbles cannot be reduced.

As a result of various studies on the chain length of the oxyalkylene group, the present inventors found that the viscosity was extremely high in the high chain length (additional mole number = 110 to 300) range of a certain specific region, and it was used together with an antifoaming agent. By doing so, the viscosity reduction and bubble entrainment are further improved. That is, when the number of moles of ethylene oxide and / or propylene oxide is within the range of 2 to 100 moles as in the known patents (the patents relating to the above-mentioned copolymers), a sufficient effect is not exhibited.

In the copolymer of the present invention, examples of the monomer (a) represented by the general formula (A) include methoxy polyethylene glycol, methoxy polyethylene polypropylene glycol, ethoxy polyethylene glycol, ethoxy polyethylene polypropylene glycol and propoxy polyethylene glycol. , An esterification product of a polyalkylene glycol with one terminal alkyl-blocked such as propoxy polyethylene polypropylene glycol and a dehydrogenation (oxidation) reaction product of acrylic acid, methacrylic acid or a fatty acid, or a dehydrogenation (oxidation) reaction product of acrylic acid, methacrylic acid or a fatty acid And ethylene oxide and propylene oxide adducts thereof are used. The number of added moles of polyalkylene glycol is 110-30
It is 0, and both additions of ethylene oxide and propylene oxide can be used in any of random addition, block addition, alternating addition, and the like. When the number of added moles of polyalkylene glycol is less than 110, the separation resistance is poor, and when it exceeds 300, the fluidity is lowered.

Examples of the compound represented by the general formula (B) include acrylic acid, methacrylic acid, crotonic acid and their metal salts. Further, as the unsaturated dicarboxylic acid-based monomer, maleic anhydride, maleic acid, itaconic anhydride, itaconic acid, citraconic anhydride, citraconic acid,
Fumaric acid or an alkali metal salt, alkaline earth metal salt, ammonium salt, amine salt or substituted amine salt thereof is used.

Examples of the compound represented by the general formula (C) include allylsulfonic acid, methallylsulfonic acid, or their alkali metal salts, alkaline earth metal salts, ammonium salts, amine salts and substituted amine salts. used.

The reaction units of the monomer (a) and the monomer (b) constituting the copolymer of the present invention are monomer (a) / monomer (b) =
The range of 0.1 / 100 to 100/100 (molar ratio) is particularly excellent in fluidity and separation resistance. When the above molar ratio is less than 0.1 / 100, the fluidity tends to decrease, and when it exceeds 100/100, the separation resistance tends to decrease.

The copolymer (A) of the present invention can be produced by a known method. For example, JP-A-59-16216
3, the Japanese Patent Publication No. 211542, the Japanese Patent Publication No. 2-7901, the Japanese Patent Publication No. 2-7897, etc. solvent polymerization methods.

The solvent used in the solvent polymerization method is
Examples thereof include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, benzene, toluene, xylene, cyclohexane, n-hexane, aliphatic hydrocarbons, ethyl acetate, acetone and methyl ethyl ketone. Water and primary to quaternary alcohols are preferable in consideration of handling and reaction equipment.

As the water-based polymerization initiator, a water-soluble initiator such as ammonium or alkali metal persulfate or hydrogen peroxide is used. Benzoyl peroxide, lauroyl peroxide and the like are used as a polymerization initiator for solvent polymerization using a solvent other than an aqueous solvent.

It is also possible to use sodium bisulfite, mercaptoethanol or an amine compound as an accelerator in combination with the polymerization initiator, and these polymerization initiators or accelerators can be appropriately selected and used. .

Weight average molecular weight of the copolymer (a) of the present invention
(Gel permeation chromatography method / sodium polystyrene sulfonate conversion) is 3,000 to 1,000,00
A range of 0 is preferable, and 5,000 to 100,000 is more preferable. If the molecular weight is too large, the fluidity will decrease, and if the molecular weight is too small, the separation resistance will tend to decrease.

Further, the copolymer (a) in the present invention is
You may react with another copolymerizable monomer within the range which does not impair the effect of this invention. For example, acrylonitrile,
Examples thereof include acrylic acid ester, acrylamide, methacrylamide, styrene, styrene sulfonic acid and the like.

The antifoaming agent (b) in the present invention is not particularly limited, but a silicon-based antifoaming agent containing dimethylpolysiloxane as a main component or an antifoaming agent containing polyalkylene glycol fatty acid ester as a main component. Is preferably used.

As the silicone type defoaming agent, an emulsifying type which is compatible with water is preferably used. As an example, Shin-Etsu Silicon Co .: KM series such as KM-70, KM-73A, Toshiba Silicon Co .: TSA series, Dow Corning Co .: FS Antifoam series, Kao Co .: Antifoam E-20 etc. Is mentioned.

As an antifoaming agent containing a polyalkylene glycol fatty acid ester as a main component, Kao Corporation: Resol
TWL120, Nichika Chemical Co., Ltd .: Nicofix, Form Rex 797 and the like.

In the admixture composition of the present invention, the copolymer
The compounding ratio of (ii) and defoamer (ii) is (ii) / (ii) = 10
0 / 0.01 to 5.0 (solid content weight ratio), 100 / 0.1 to
1.0 is preferably used. If it is less than 100 / 0.01, the defoaming effect is not sufficient, and if it exceeds 100 / 5.0, the dispersibility tends to decrease.

The addition amount of the copolymer (a) of the present invention is about 0.02 to 1.0% by weight based on the solid content of the cement, and 0.1 to 0.5% by weight is preferably used.

Further, the admixture composition of the present invention may be added by premixing the copolymer (a) and the defoaming agent (b) or by adding them separately. It is not something that will be done.

The admixture composition of the present invention is used for the production of concrete products for compaction by a vibration machine and the acceleration of gravity of 3G.
Used to manufacture concrete products that are molded by applying a centrifugal force of ~ 60G.

Furthermore, recently, studies have been conducted on high-fluidity concrete which is a self-filling concrete that does not use a vibrator, but it can be used as an admixture composition in the production of concrete products using these concretes. . Here, high fluidity concrete is concrete
Represents concrete that exhibits fluidity of about 45 cm (flow value based on JIS A-1101 slump test).

The concrete to which the present invention is applied has cement, fine aggregate and coarse aggregate as main components, but various admixture materials such as various blast furnace slags and fly ash can be used. Furthermore, it can be used in combination with known additives (materials). For example, AE agent, AE water reducing agent, high performance water reducing agent, retarder, early strengthening agent, accelerator, foaming agent, foaming agent,
Examples thereof include thickeners, waterproofing agents, antifoaming agents and the like.

[0033]

EXAMPLES The present invention will be specifically described below, but the present invention is not limited to these examples. In addition, "%" in the following examples is "% by weight" unless otherwise specified.

Further, the average molecular weight of the copolymer (a) shown in the examples is obtained from the gel permeation chromatography method / molecular weight in terms of sodium polystyrene sulfonate.

The contents and symbols of the monomer (a) used in the polymerization of the present invention are shown below. However, EO is ethylene oxide, PO
Represents propylene oxide.

A-1: Methanol EO / methacrylic acid monoester (EO addition mole number = 115) A-2: Methanol EO / acrylic acid monoester (EO addition mole number = 220) A-3: Methanol EO / methacrylic acid Monoester (EO
Addition mol number = 280) A-4: Acrylic acid EO adduct (EO addition mol number = 130) A-5: Acrylic acid PO / EO block adduct (PO addition mol number = 10 / EO addition mol number = 135) A-6: Acrylic acid EO / PO block addition product (EO addition mole number = 135 / PO addition mole number = 5) A-7: Methanol EO / methacrylic acid monoester (EO
Addition mol number = 23) (Comparison) A-8: Methanol EO / methacrylic acid monoester (EO
Addition mol number = 102) (Comparison) A-9: Methanol EO / methacrylic acid monoester (EO
Number of added moles = 350) (comparison).

The production examples of the copolymer (a) are shown below. Production Example 1 (Symbol C-1 for admixture) 10 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C in a nitrogen atmosphere. A-1
0.09 mol and acrylic acid 1 mol (molar ratio = 9/100), water
A mixture of 7.5 mol, 0.01 mol of a 20% aqueous solution of ammonium persulfate, and 4 g of 2-mercaptoethanol were added dropwise to the reaction system simultaneously over 2 hours.
Next, 0.03 mol of 20% ammonium persulfate aqueous solution is added dropwise over 30 minutes, and the mixture is aged at the same temperature (75 ° C) for 1 hour. After aging 95
The temperature is raised to ℃, 12g of 35% hydrogen peroxide is added dropwise over 1 hour, and the mixture is aged at the same temperature (95 ℃) for 2 hours. After aging, 48
Add 0.7 mol% sodium hydroxide to neutralize, molecular weight 22,0
A copolymer of 00 was obtained.

Production Example 2 (Symbol C-2 for admixture) 8 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C. in a nitrogen atmosphere. A-2
0.05 mol and 1 mol of methacrylic acid (molar ratio = 5/100), water
A mixture of 8.5 mol, 0.01 mol of a 20% ammonium persulfate aqueous solution, and 3 g of 2-mercaptoethanol were simultaneously added dropwise to the reaction system over 2 hours.
Next, 0.03 mol of 20% ammonium persulfate aqueous solution is added dropwise over 30 minutes, and the mixture is aged at the same temperature (75 ° C) for 1 hour. After aging 95
The temperature is raised to 0 ° C., 9 g of 35% hydrogen peroxide is added dropwise over 1 hour, and the mixture is aged at the same temperature (95 ° C.) for 2 hours. After aging, 48
Add 0.7 mol% sodium hydroxide to neutralize, molecular weight 85,0
A copolymer of 00 was obtained.

Production Example 3 (Symbol C-3 for admixture) 5 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 95 ° C in a nitrogen atmosphere. A-3
20 with a mixture of 0.002 mol, 1 mol of maleic acid monosodium salt (molar ratio = 0.2 / 100), and 15 mol of 90 ° C warm water
% Mol ammonium persulfate aqueous solution 0.01 mol, and 2-mercaptoethanol 3 g simultaneously into the reaction system
Drop over time. Next, 0.03 mol of 20% ammonium persulfate aqueous solution was added dropwise over 30 minutes, and the temperature was kept at the same temperature (95 ° C) for 1 hour.
Mature in. After aging, 9% of 35% hydrogen peroxide was added dropwise at 95 ° C over 1 hour, and the mixture was aged at the same temperature (95 ° C) for 2 hours. After aging, add 0.7 mol of 48% sodium hydroxide to neutralize,
A copolymer having a molecular weight of 12,000 was obtained.

Production Example 4 (Symbol C-4 of admixture) 10 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C in a nitrogen atmosphere. A-4
A mixture of 0.01 mol, 0.9 mol of acrylic acid, 0.1 mol of sodium methallyl sulfonate (molar ratio = 1/90/10) and 7.5 mol of water and dissolved, and a 20% ammonium persulfate aqueous solution 0.01
Mol and 2-mercaptoethanol (4 g) are simultaneously added dropwise to the reaction system over 2 hours. Next, 0.03 mol of 20% ammonium persulfate aqueous solution was added dropwise over 30 minutes,
Aging at the same temperature (75 ℃) for 1 hour. After aging, the temperature is raised to 95 ° C., 12 g of 35% hydrogen peroxide is added dropwise over 1 hour, and aging is performed at the same temperature (95 ° C.) for 2 hours. After completion of aging, 0.6 mol of 48% sodium hydroxide was added for neutralization to obtain a copolymer having a molecular weight of 7,200.

Production Example 5 (Symbol C-5) A reaction vessel equipped with a stirrer was charged with 10 mol of water, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C. in a nitrogen atmosphere. A-5
0.01 mol and 1 mol of methacrylic acid (molar ratio = 1/100), water
A mixture of 7.5 mol, 0.01 mol of a 20% aqueous solution of ammonium persulfate, and 1 g of 2-mercaptoethanol are simultaneously added dropwise to the reaction system over 2 hours.
Next, 0.03 mol of 20% ammonium persulfate aqueous solution is added dropwise over 30 minutes, and the mixture is aged at the same temperature (75 ° C) for 1 hour. After aging 95
The temperature is raised to 0 ° C., 5 g of 35% hydrogen peroxide is added dropwise over 1 hour, and the mixture is aged at the same temperature (95 ° C.) for 2 hours. After aging, 48
Add 0.7 mol% sodium hydroxide to neutralize, molecular weight 105,
000 copolymers were obtained.

Production Example 6 (Symbol C-6 as an admixture) 10 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C in a nitrogen atmosphere. A-6
0.01 mol and 1 mol of sodium acrylate (molar ratio = 1 /
100), 7.5 mol of water mixed and dissolved, 0.01 mol of 20% ammonium persulfate aqueous solution, and 2 g of 2-mercaptoethanol are simultaneously added dropwise to the reaction system over 2 hours. Next, 0.03 mol of 20% ammonium persulfate aqueous solution
Drop over 30 minutes and age for 1 hour at the same temperature (75 ° C).
After aging, the temperature is raised to 95 ° C., 9 g of 35% hydrogen peroxide is added dropwise over 1 hour, and aging is performed at the same temperature (95 ° C.) for 2 hours. After the aging was completed, 48 mol of sodium hydroxide (0.7 mol) was added for neutralization to obtain a copolymer having a molecular weight of 77,000.

Production Example 7 (Symbol C-7 as an admixture) 23 mol of water was placed in a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C in a nitrogen atmosphere. A-2
0.045 mol and acrylic acid 0.3 mol (molar ratio = 15/100),
A mixture of 10 mol of water and 0.003 mol of 20% ammonium persulfate aqueous solution, and 2-mercaptoethanol 1.2.
g of each of the three is simultaneously added dropwise to the reaction system over 2 hours. Next, 0.009 mol of a 20% ammonium persulfate aqueous solution is added to 30%.
Drop over a period of minutes and age for 1 hour at the same temperature (75 ° C). After aging, the temperature is raised to 95 ° C., 4 g of 35% hydrogen peroxide is added dropwise over 1 hour, and aging is performed at the same temperature (95 ° C.) for 2 hours. After the completion of aging, 0.21 mol of 48% sodium hydroxide was added for neutralization to obtain a copolymer having a molecular weight of 51,000.

Production Example 8 (Symbol C-8 as an admixture) 23 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C in a nitrogen atmosphere. A-
1 0.08 mol and acrylic acid 0.2 mol (molar ratio = 40/100)
, A mixture of 12 mol of water and 0.002 mol of 20% ammonium persulfate aqueous solution, and 2-mercaptoethanol
0.6 g of each of the three substances is dropped simultaneously into the reaction system over 2 hours. Next, 0.006 mol of a 20% ammonium persulfate aqueous solution is added dropwise over 30 minutes, and the mixture is aged at the same temperature (75 ° C) for 1 hour. After aging, the temperature is raised to 95 ° C., 3 g of 35% hydrogen peroxide is added dropwise over 1 hour, and aging is performed at the same temperature (95 ° C.) for 2 hours. After the aging was completed, 0.14 mol of 48% sodium hydroxide was added to neutralize and obtain a copolymer having a molecular weight of 56,000.

Production Example 9 (symbol C-9 as an admixture) 18 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C in a nitrogen atmosphere. A-1
0.06 mol and acrylic acid 0.1 mol (molar ratio = 60/100),
A mixture of 8 moles of water, 0.001 mole of 20% aqueous ammonium persulfate solution, and 2-mercaptoethanol 0.3
g of each of the three is simultaneously added dropwise to the reaction system over 2 hours. Next, 0.003 mol of 20% ammonium persulfate aqueous solution is added to 30%.
Drop over a period of minutes and age for 1 hour at the same temperature (75 ° C). After aging, the temperature is raised to 95 ° C., 2 g of 35% hydrogen peroxide is added dropwise over 1 hour, and aging is performed at the same temperature (95 ° C.) for 2 hours. After completion of the aging, 0.07 mol of 48% sodium hydroxide was added for neutralization to obtain a copolymer having a molecular weight of 45,000.

Production Example 10 (symbol C-10 as an admixture) 30 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C in a nitrogen atmosphere. A-1
0.1 mol and acrylic acid 0.1 mol (molar ratio = 100/100), water
A mixture of 13 mol and dissolved, 0.001 mol of 20% ammonium persulfate aqueous solution, and 0.3 g of 2-mercaptoethanol
Each of the three is simultaneously added dropwise to the reaction system over 2 hours. Next, 0.003 mol of 20% ammonium persulfate aqueous solution is added to 30%.
Drop over a period of minutes and age for 1 hour at the same temperature (75 ° C). After aging, the temperature is raised to 95 ° C., 2 g of 35% hydrogen peroxide is added dropwise over 1 hour, and aging is performed at the same temperature (95 ° C.) for 2 hours. After completion of the aging, 0.07 mol of 48% sodium hydroxide was added for neutralization to obtain a copolymer having a molecular weight of 72,000.

Production Example 11 (Symbol C-11 for admixture) 10 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C in a nitrogen atmosphere. A-7
0.1 mol and acrylic acid 1 mol (molar ratio = 10/100), water
A mixture of 7.5 mol, 0.01 mol of a 20% aqueous solution of ammonium persulfate, and 4 g of 2-mercaptoethanol were added dropwise to the reaction system simultaneously over 2 hours.
Next, 0.03 mol of 20% ammonium persulfate aqueous solution is added dropwise over 30 minutes, and the mixture is aged at the same temperature (75 ° C) for 1 hour. After aging 95
The temperature is raised to ℃, 12g of 35% hydrogen peroxide is added dropwise over 1 hour, and the mixture is aged at the same temperature (95 ℃) for 2 hours. After aging, 48
Add 0.7 mol% sodium hydroxide to neutralize, molecular weight 11,0
A copolymer of 00 was obtained.

Production Example 12 (symbol C-12 as an admixture) 10 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C in a nitrogen atmosphere. A-8
0.05 mol and acrylic acid 1 mol (molar ratio = 5/100), water
A mixture of 7.5 mol, 0.01 mol of a 20% ammonium persulfate aqueous solution, and 3 g of 2-mercaptoethanol are simultaneously added dropwise to the reaction system over 2 hours.
Next, 0.03 mol of 20% ammonium persulfate aqueous solution is added dropwise over 30 minutes, and the mixture is aged at the same temperature (75 ° C) for 1 hour. After aging 95
The temperature is raised to 10 ° C., 10 g of 35% hydrogen peroxide is added dropwise over 1 hour, and the mixture is aged at the same temperature (95 ° C.) for 2 hours. After aging, 48
Add 0.7 mol% sodium hydroxide to neutralize, molecular weight 31,0
A copolymer of 00 was obtained.

Production Example 13 (Symbol C-13 of admixture) 5 mol of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 95 ° C in a nitrogen atmosphere. A-9
0.005 mol and acrylic acid 1 mol (molar ratio = 0.5 / 100), 75
Mixture of 15 mol of warm water, 0.01 mol of 20% ammonium persulfate aqueous solution, and 2-mercaptoethanol 3
g of each of the three is simultaneously added dropwise to the reaction system over 2 hours. Next, 0.03 mol of a 20% ammonium persulfate aqueous solution is added dropwise over 30 minutes, followed by aging at the same temperature (95 ° C) for 1 hour. After aging, add 9 g of 35% hydrogen peroxide at 95 ° C over 1 hour, and add 2
Aging at the same temperature (95 ℃) for a certain period of time. After completion of the aging, 0.7 mol of 48% sodium hydroxide was added to neutralize and obtain a copolymer having a molecular weight of 25,000.

The contents and symbols of the comparative admixtures used in the examples are shown below, in addition to the comparative polymer of the copolymer. Symbol for admixture NS: Naphthalene admixture (Mighty 150
; Kao Corporation) Admixture symbol MS: Melamine admixture (Mighty 150V-
2; manufactured by Kao Corporation.

Table 1 shows the contents and symbols of the defoaming agent (b) used in the examples.

[0052]

[Table 1]

Evaluation Method of Concrete Test Tables 2 to 4 show concrete mixing conditions. Table 2 shows the composition for vibration compaction concrete products, Table 3 shows the composition for centrifugal compaction concrete products, and Table 4 shows the composition for high flow concrete products.

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

1. Evaluation of vibration compacted concrete product The slump value was adjusted to 10 ± 1 cm by adding the admixture composition of the present invention and the comparative admixture in the concrete composition shown in Table 2. After that, machine oil is applied as a release agent with a diameter of 15c
Concrete was packed in a cylindrical mold having a height of 30 cm and a height of 30 cm, and vibration filling was performed for 15 seconds using a table vibrator to mold a test body. The number of bubbles having a diameter of 2 mm or more on the surface of the concrete after hardening was counted for an area of 100 cm ² , and the surface aesthetics was judged as follows. ○ -4 or less △ -5 to 19 × -20 or more Further, the slump value immediately after concrete production was measured by the JIS A 1101 method. The test results are shown in Table 5.

[0058]

[Table 5]

2. Evaluation of Centrifugal Compacted Concrete Product With the concrete composition shown in Table 3, the admixture composition of the present invention and a comparative admixture were added to adjust the slump value to 3 ± 1 cm. Then, 13 kg of concrete was put into a centrifugal molding form having a diameter of 20 cm and a height of 30 cm, and centrifugal compaction was performed. The strength of the hardened concrete was measured by the compaction time and the degree of compaction of the concrete was visually observed. The centrifugal conditions were as follows: gravity acceleration of 5 G for 1 minute, 15 G for 2 minutes, 30 G for 2 minutes, 4 minutes, and 6 minutes. Degree of concrete tightening ○ − Smoothly tightened. △ -Slightly poor smoothness on the inner or outer surface. × -Exposed gravel and the inner or outer surface is extremely poor in smoothness. Further, the slump value and the compressive strength were measured as follows. -Slump value: The value immediately after concrete production was measured by the JIS A 1101 method. -Compressive strength: A cylindrical specimen having a diameter of 10 cm and a height of 20 cm was prepared, and the strength after 28 days was measured by the JIS A 1108 method. The measurement results are shown in Table 6.

[0060]

[Table 6]

3. Evaluation of high-fluidity concrete products The admixture composition of the present invention and the comparative admixture were added in the concrete composition shown in Table 4 to adjust the slump value to 55 ± 5 cm.
Then, concrete was filled into a cylindrical mold having a diameter of 15 cm and a height of 30 cm coated with machine oil as a release agent, and a test body was molded. The number of bubbles having a diameter of 2 mm or more on the surface of the concrete after hardening was counted for an area of 100 cm ² , and the surface aesthetics was judged as follows. ○ -4 or less △ -5 to 19 × -20 or more Further, the slump value immediately after concrete production was measured by the JIS A 1101 method. The test results are shown in Table 7.

[0062]

[Table 7]

Evaluation Results As is clear from Tables 5 and 7, the hardened concrete produced from the admixture composition of the present invention is remarkably reduced in surface bubbles, and the surface aesthetic appearance is remarkably improved. Further, as is clear from Table 6, the centrifugation time can be shortened. Therefore, it is possible to rationalize the production because it is not necessary to repair surface bubbles and the centrifugation time can be shortened.

Claims (9)

[Claims] 1. A monomer (a) represented by the following general formula (A):
And a copolymer (a) obtained by polymerizing a monomer (b) selected from the compounds represented by the following general formulas (B) and (C), and an antifoaming agent ( (B) An admixture composition for concrete products, which contains (b) as an essential component. Embedded image (In the formula, R ₁ and R ₂ : hydrogen, a methyl group m ₁ : an integer of 0 to 2 AO: an oxyalkylene group having 2 to 3 carbon atoms n: an integer of 110 to 300 X: hydrogen or a carbon number of 1 to 3 Represents an alkyl group.) (In the formula, R _{3 to} R ₅ : hydrogen, methyl group, (CH ₂ ) m ₂ COOM ₂ R ₆ : hydrogen, methyl group M ₁ , M ₂ , Y: hydrogen, alkali metal, alkaline earth metal, ammonium, (Alkyl ammonium or substituted alkyl ammonium m ₂ : represents an integer of 0 to _2. ) 2. A monomer (a) constituting the copolymer (a),
The reaction unit of monomer (b) is monomer (a) / monomer (b) =
The admixture composition for concrete products according to claim 1, which has a molar ratio of 0.1 / 100 to 100/100. 3. The admixture composition for concrete products according to claim 1, wherein the copolymer (a) has a weight average molecular weight (gel permeation chromatography method / sodium polystyrene sulfonate conversion) of 3,000 to 1,000,000. 4. The blending ratio of the copolymer (a) and the defoaming agent (b) is (a) / (b) = 100 / 0.01 to 5.0 (solid content weight ratio).
The admixture composition for concrete products according to any one of claims 1 to 3. 5. The admixture composition for concrete products according to any one of claims 1 to 4, wherein the main component of the defoaming agent (b) is dimethylpolysiloxane. 6. The admixture composition for concrete products according to any one of claims 1 to 4, wherein a main component of the defoaming agent (b) is a polyalkylene glycol fatty acid ester. 7. The admixture composition for concrete products according to any one of claims 1 to 6, which is used for producing a concrete product that is compacted by a vibrator. 8. The admixture composition for concrete products according to any one of claims 1 to 6, which is used for producing a concrete product which is molded by applying a centrifugal force of gravity acceleration of 3 G to 60 G. 9. The admixture composition for concrete products according to claim 1, wherein the admixture composition for concrete products is used for producing a concrete product which is filled and molded in a state of high-fluidity concrete without using a vibrator. Stuff.