JPH09188554A - Admixture for highly fluid concrete and production of highly fluid concrete using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the compaction in placing a concrete and improve the environment in noise by including a specific copolymer and a water-soluble salt of a naphthalenesulfonic acid-formaldehyde condensate in an admixture. SOLUTION: This admixture is obtained by blending a copolymer, prepared by eopolymerizing a monomer of formula I [R1 and R2 are each H or methyl; (m1 ) is 0-2; AO is a 2-3C oxyalkylene; (n) is 2-100; X is H or a 1-3C alkyll with a monomer of formula II [R3 to R6 are each H, methyl or one to two COOM groups; M is H, an alkali(alkaline earth) metal, ammonium or a (substituted) alkylammonium] or formula III [R7 is R1 ; Y is H, an alkali(alkaline earth) metal, ammonium or a (substituted) alkylammonium] at (1/100) to (100/100) molar ratio and having 2000-500000 weight-average molecular weight (measured by a get permeation chromatography/expressed in terms of sodium styrenesulfonate) with a water-soluble salt of a naphthalenesulfonic acid- formaldehyde condensate having 2000-500000 weight-average molecular weight so as to provide (100/1) to (100/80) weight ratio of the copolymer to the water- soluble salt of the naphthalenesulfonlc acid-formaldehyde condensate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an admixture for high-fluidity concrete having excellent fluidity and separation resistance of concrete and a method for producing high-fluidity concrete using the admixture.
More specifically, the admixture for high-fluidity concrete and the production of high-fluidity concrete using the admixture, which reduces or eliminates the compaction during casting and improves the environment against noise, and is used in the production of concrete products such as civil engineering and construction. It is about the method.

[0002]

2. Description of the Related Art In recent years,
The concrete industry is said to be the representative of 3K (tight, dirty, dangerous), and among them, environmental problems against noise have been pointed out. In response to this, research has begun to improve fluidity and eliminate the need for a vibrator. However, simply adding water or a dispersant to increase the fluidity causes material separation, the coarse aggregates are entangled with each other, and the filling property is deteriorated, and uniform concrete cannot be obtained, resulting in a decrease in strength.
Addition of water-soluble polymers and mixing of fine powders have been studied for the purpose of suppressing this material separation (for example, Annual Review of Concrete Engineering, 1989.6, Paper No. 1118 “Development of High Performance Concrete”).

However, as compared with general concrete, high-fluidity concrete is extremely sensitive to slight fluctuations in the amount of water, causes material separation, etc., and must maintain a predetermined fluidity. Is a difficult situation.

[0004]

Means for Solving the Problems As a result of earnest research, the present inventors have found that a polyalkylene glycol ester-based monomer (a) and an acrylic acid-based monomer having an oxyalkylene group having 2 to 3 carbon atoms added thereto. A copolymer (a) obtained by polymerizing at least one monomer (b) selected from unsaturated dicarboxylic acid type monomers and allyl sulfonic acid type monomers, and naphthalene sulfonic acid formaldehyde By using an admixture which essentially contains two components of the water-soluble condensate salt (b) and the weight ratio of the two components is (a) / (b) = 100/1 to 100/80, high fluidity can be obtained. This makes it possible to easily produce concrete having excellent properties and separation resistance.

That is, the present invention is one kind selected from a monomer (a) represented by the following general formula (A) and a compound represented by the following general formulas (B) and (C). A copolymer (a) obtained by polymerizing the above monomer (b) and a water-soluble salt of a naphthalenesulfonic acid formaldehyde condensate (b) are essentially contained, and the weight composition ratio of the two components is Is (a) / (b)
= 100/1 to 100/80, and an admixture for high-fluidity concrete, and a method for producing high-fluidity concrete using the same.

[0006]

Embedded image

(Wherein R ₁ and R _{2 are} hydrogen or a methyl group m ₁ : 0 to 2 number AO: an oxyalkylene group having 2 to 3 carbon atoms n: 2 to 100 number X: hydrogen or carbon number 1 ~ Represents an alkyl group of 3).

[0008]

Embedded image

(In the formula, R _{3 to} R ₆ : hydrogen, methyl group or COOM
(However, COOM is one or two) M: hydrogen, alkali metal, alkaline earth metal, ammonium, alkyl ammonium or substituted alkyl ammonium Y: hydrogen, alkali metal, alkaline earth metal, ammonium, alkyl ammonium or substituted Alkylammonium R ₇ : represents hydrogen or a methyl group. The components (a) and (b) are known as cement dispersants, and their individual properties are effective in developing fluidity, but do not show separation resistance. The present inventors have found that when the component (a) and the component (b) are used in concrete at a specific mixing ratio, a pseudo-dispersion which has fluidity and separation resistance occurs and is used. As a result, it is possible to produce high-fluidity concrete that has little influence of surface water of the aggregate and fluctuation of water amount and can obtain stable fluidity.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the copolymer (a) according to the present invention, the monomer (a) represented by the general formula (A) includes methoxy polyethylene glycol, methoxy polyethylene polypropylene glycol, ethoxy polyethylene glycol, An esterified product of an alkyl-capped polyalkylene glycol such as ethoxypolyethylene polypropylene glycol, propoxypolyethylene glycol, or propoxypolyethylene polypropylene glycol with acrylic acid or methacrylic acid, or an ethylene oxide or propylene oxide adduct of acrylic acid or methacrylic acid is used. The number of moles of polyalkylene glycol added is from 2 to 100, and both ethylene oxide and propylene oxide adducts are random addition, block addition,
Any of alternate addition and the like can be used.

When the number of added moles of polyalkylene glycol is less than 2 or exceeds 100, the fluidity and separation resistance are poor.

Examples of the compound represented by the general formula (B) in the monomer (b) include acrylic acid-based monomers such as acrylic acid, methacrylic acid, crotonic acid, or alkali metal salts or alkaline earth salts thereof. Mention may be made of metal salts, ammonium salts, amine salts or substituted amine salts. Further, as the unsaturated dicarboxylic acid-based monomer, maleic acid, itaconic acid,
Examples thereof include citraconic acid, fumaric acid, or an alkali metal salt, alkaline earth metal salt, ammonium salt, amine salt or substituted amine salt thereof.

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

The reaction units of the monomers (a) and (b) constituting the copolymer (a) according to the present invention are monomer (a) / (b) = 1 /
The range of 100 to 100/100 (molar ratio) is particularly excellent in fluidity and separation resistance. When the above molar ratio is smaller than 1/100 or larger than 100/100, the fluidity and separation resistance tend to decrease.

The copolymer (a) according to the present invention can be produced by a known method. For example, JP-A-59-1
No. 62163, Japanese Patent Fair 2-11542, Japanese Patent Fair 2-7901, Japanese Fair
Solvent polymerization methods such as those disclosed in JP-A-2-7897 are mentioned.

The solvent used in the solvent polymerization is water,
Methyl alcohol, ethyl alcohol, isopropyl alcohol, benzene, toluene, xylene, cyclohexane, n-hexane, aliphatic hydrocarbons, ethyl acetate, acetone, methyl ethyl ketone and the like can be mentioned. 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 or the like is used as a polymerization initiator in 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. .

The weight average molecular weight (gel permeation chromatography method / polystyrene sulfonic acid conversion) of the copolymer (a) is preferably in the range of 2,000 to 500,000,
More preferably, it is 100 to 100,000. If the molecular weight is too high, the fluidity tends to decrease, and if the molecular weight is too low, the dispersibility tends to decrease.

The naphthalenesulfonic acid formaldehyde condensate (B) in the present invention is a known cement dispersant, and for example, Mighty 150 (manufactured by Kao Corporation) is used.
The molecular weight of this component (b) is preferably in the range of 2,000 to 50,000 (gel permeation chromatography / sodium styrenesulfonate conversion), and 5,000 to 30,000.
Is more preferably used.

In the admixture of the present invention, the weight composition ratio of the component (a) and the component (b) is (a) / (b) = 100/1 to
100/80, preferably 100/3 to 100/50, and more preferably 100/10 to 100/30 are extremely excellent in fluidity and separation resistance. It becomes difficult to prepare high fluidity concrete.

The addition amount of the admixture of the present invention is preferably 0.02 to 1.0% by weight (solid content) relative to cement, and 0.1 to 0.
5% by weight is more preferred.

Further, the addition method of the admixture of the present invention at the time of producing concrete may be a method of adding it to a mixer at the same time as the concrete material, or a method of adding it to the pre-kneaded concrete after addition. The components (a) and (b) may not be mixed in advance and may be added separately so that the weight ratio of the addition amounts is (a) / (b) = 100/1 to 100/80. The addition method and the addition timing are not limited in any way.

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. Further, known additives (materials) can be used in combination. For example, an AE agent, an AE water reducing agent, a high performance water reducing agent, a retarder, an early strengthening agent, an accelerator, a foaming agent, a foaming agent, an antifoaming agent, a thickener, a waterproofing agent, an antifoaming agent and the like can be mentioned.

The concrete composition which is the object of the present invention is used for concrete moldings. The concrete compact is not particularly limited, and a compact compacted by an ordinary vibrator is targeted. Further, the concrete composition which is the object of the present invention can be used for a secondary product requiring initial strength.

The concrete composition which is the object of the present invention does not require compaction by a vibrator, but it has a fine vibration range (for example, 1/10 to 1/1 of a normal vibration range).
Compaction in the frequency range of 3 is also possible.

[0027]

EXAMPLES Hereinafter, the present invention will be described specifically, but the present invention is not limited to these examples.

The weight 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.

<Production Example of Copolymer (a)> The contents and symbols of the monomer (A) used in the polymerization of the present invention are shown below. However, EO represents ethylene oxide and PO represents propylene oxide. A-1 Methanol EO / methacrylic acid monoester (EO
Addition mole number = 9) A-2 Methanol EO / acrylic acid monoester (EO addition mole number = 23) A-3 Methanol EO / methacrylic acid monoester (EO
Addition mol number = 45) A-4 Acrylic acid PO / EO block adduct (PO addition mol number = 10 / EO addition mol number = 50) A-5 Methanol EO / acrylic acid monoester (EO addition mol number = 90) The production examples of the copolymer (a) are shown below.

Production Example 1 (Symbol A-1 for Copolymer) A reaction vessel equipped with a stirrer was charged with 5 mol of water, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 75 ° C. in a nitrogen atmosphere. A-1
0.30 mol, 1 mol of acrylic acid (molar ratio = 30/100), 5 mol of water mixed and dissolved, 20% ammonium persulfate aqueous solution 0.01 mol, and 2-mercaptoethanol 4 g 3 g
Are 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, and the mixture is aged at the same temperature (75 ° C.) for 1 hour. 95 ℃ after aging
The temperature is raised to 12, and 12 g of 35% hydrogen peroxide is added dropwise over 1 hour, followed by aging for 2 hours at the same temperature (95 ° C). After aging, 48
Neutralized by adding 0.7 mol of sodium hydroxide, molecular weight 22,0
Thus, a copolymer No. 00 was obtained.

Production Example 2 (Code A-2 for Copolymer) A reaction vessel equipped with a stirrer was charged with 5 mol of water, and while substituting with nitrogen, the temperature was raised to 75 ° C. in a nitrogen atmosphere. A-2
0.20 mol, 1 mol of methacrylic acid (molar ratio = 20/100),
A mixture of 5 mol of water, 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 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. 95 after aging
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 35,0
Thus, a copolymer No. 00 was obtained.

Production Example 3 (Symbol A-3 of Copolymer) A reaction vessel equipped with a stirrer was charged with 8 mol of water, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 95 ° C. in a nitrogen atmosphere. A-3
0.20 mol, 1 mol of maleic acid monosodium salt (molar ratio = 20/100), 8 mol of 90 ° C warm water mixed and dissolved
% Mol ammonium persulfate aqueous solution 0.01 mol, and 2-mercaptoethanol 3 g simultaneously into the reaction system
Drip over time. Next, 0.03 mol of a 20% ammonium persulfate aqueous solution is added dropwise over 30 minutes, and the same temperature (95 ° C) for 1 hour
And mature. After aging, 9 g of 35% hydrogen peroxide is added dropwise at 95 ° C. over 1 hour, and aging is performed 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 17,000 was obtained.

Production Example 4 (Symbol A-4 of Copolymer) 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
0.10 moles, acrylic acid 0.8 moles, sodium methallyl sulfonate 0.1 moles (molar ratio = 10/80/10), water
7.5 mol mixed and dissolved, 0.01 mol of 20% ammonium persulfate aqueous solution, and 3 g of 2-mercaptoethanol 4 g
Are 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, and the mixture is aged at the same temperature (75 ° C.) for 1 hour. 95 ℃ after aging
The temperature is raised to 12, and 12 g of 35% hydrogen peroxide is added dropwise over 1 hour, followed by aging for 2 hours at the same temperature (95 ° C). After aging, 48
Add 0.6 mol% sodium hydroxide to neutralize, molecular weight 13,0
Thus, a copolymer No. 00 was obtained.

Production Example 5 (Symbol A-5 of Copolymer) 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-5
0.1 mol, 1 mol of methacrylic acid (molar ratio = 10/100),
7.5 mol of water mixed and dissolved, 0.01 mol of 20% ammonium persulfate aqueous solution, and 1 g of 2-mercaptoethanol
Are simultaneously dropped into the reaction system over 2 hours. Next, 0.03 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., 5 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, 0.7 mol of 48% sodium hydroxide was added for neutralization to obtain a copolymer having a molecular weight of 55,000.

As the component (b) used in the examples, naphthalenesulfonic acid formaldehyde condensate sodium salt (symbol NS: Mighty 150; manufactured by Kao Corporation, molecular weight 13,000) was used.

<Evaluation Method by Concrete Test> Table 1 shows the materials used for concrete mixing.

[0037]

[Table 1]

Table 2 shows the mixing conditions of concrete.

[0039]

[Table 2]

In the method for producing concrete, the materials shown in Table 1 were blended with the compounds shown in Table 2 by an omnimixer (manufactured by Chiyoda Giken Kogyo Co., Ltd.) for 1 minute in the air and 1 minute after the addition of water. The (A) component and the (B) component are added at the same time as the (O) method of adding the materials shown in Table 1, and the (A) component is added at the same time as the materials of the Table 1 and kneaded for 2 minutes to give the (B) component. The post-addition method (F) was performed, and the method (F) was kneaded for 30 seconds to produce concrete. The fluidity was adjusted by the addition amount of the admixture so that the concrete composition-2 was 55 to 65 cm (flow value according to JIS A-1101 slump test).

The evaluation was carried out by measuring the material separation resistance and the self-filling property shown below. -Material separation resistance: judged by the naked eye after measuring the concrete flow. The evaluation criteria are as follows. ○ − No separation of aggregate and mortar △ − Slight separation of aggregate and mortar × − Separation of aggregate and mortar ・ Self-filling: Put the manufactured concrete into a cylinder mold of φ10vm and vibrate. Was packed for 3 days without use, and then the mold was removed and the state of the concrete surface was visually observed. The evaluation criteria are as follows.

∙ Almost no voids of -5 mm or more were found. △ -5 Voids of 5 mm or more were slightly found.

The evaluation results are shown in Tables 3 and 4.

[0044]

[Table 3]

[0045]

[Table 4]

<Evaluation Results> As shown in Tables 3 and 4,
The admixture of the present invention has a larger material separation resistance and a better self-filling property than the comparative product despite the fluctuation of the unit water amount.

[0047]

EFFECTS OF THE INVENTION The admixture of the present invention facilitates the production of high-fluidity concrete and dramatically improves the construction method. It helps to eliminate noise and rationalize the production of concrete structures. The effect of is expected.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C04B 103: 40 (72) Inventor Ya Fujikura Wakayama Prefecture Wakayama City Minato 1334 Kao Research Laboratory ( 72) Inventor Kenichi Obata 1-14-1 Nihonbashi Kayabacho, Chuo-ku, Tokyo Kao Co., Ltd.

Claims (5)

[Claims] 1. A monomer (a) represented by the following general formula (A)
And a copolymer (a) obtained by polymerizing at least one monomer (b) selected from compounds represented by the following general formulas (B) and (C) with naphthalene sulfonic acid formaldehyde The water-soluble condensate (b) contains two components as essential components, and the weight composition ratio of the two components is (a) / (b) = 100/1 to 1
00/80, an admixture for high-fluidity concrete. Embedded image (In the formula, R ₁ and R ₂ : hydrogen or a methyl group m ₁ : the number of 0 to 2 AO: an oxyalkylene group having 2 to 3 carbon atoms n: the number of 2 to 100 X: hydrogen or a carbon number of 1 to 3 Represents an alkyl group.) (In the formula, R _{3 to} R ₆ : hydrogen, methyl group or COOM (where COOM is one or two) M: hydrogen, alkali metal, alkaline earth metal, ammonium, alkylammonium or substituted alkylammonium Y: Hydrogen, alkali metal, alkaline earth metal, ammonium, alkylammonium or substituted alkylammonium R ₇ : represents hydrogen or a methyl group.) 2. A monomer (a) constituting the copolymer (a),
The reaction unit of (b) is monomer (a) / monomer (b) = 1/100
The admixture for high-fluidity concrete according to claim 1, wherein the admixture is 100 to 100 (molar ratio). 3. The weight average molecular weight of the copolymer (a) is 2,0.
The admixture for high-fluidity concrete according to claim 1 or 2, wherein the admixture is from 00 to 500,000 (based on gel permeation chromatography / sodium styrenesulfonate conversion). 4. The weight average molecular weight of the water-soluble salt of naphthalenesulfonic acid formaldehyde condensate (b) is 2,000 to 50,0.
00 (gel permeation chromatography method / in terms of sodium styrenesulfonate).
The admixture for high-fluidity concrete according to any one of 1 to 3. 5. A method for producing high-fluidity concrete using the admixture for high-fluidity concrete according to any one of claims 1 to 4.