JP2960408B1 - Concrete production method - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To improve the surface appearance of concrete obtained by using a concrete composition containing a polyalkylene glycol monoester copolymer. SOLUTION: A concrete composition containing a copolymer of a monomer (a) of the general formula (A) and one or more monomers (b) selected from the general formulas (B) and (C), A method for producing concrete in which a mold containing a sorbitan fatty acid ester and containing no mineral oil containing no phospholipids and unsaturated fatty acids is filled and hardened. Embedded image [Wherein, R ₁ and R _{2 are a} hydrogen atom or a methyl group, m ₁ is an integer of 0 to 2, A
O: an oxyalkylene group having 2 to 3 carbon atoms, n: a number of 60 to 300, X: a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ] Wherein R ₃ , R ₆ : hydrogen atom or methyl group, R ₄ , R ₅ : hydrogen atom, methyl group or M ₂ O (CO) (CH ₂ ) m ₂ , M ₁ , M ₂ , Y: hydrogen shows 0-2 integers of: atom, an alkali metal, alkaline earth metal, ammonium, hydroxyl mono substituted, di-, trialkyl ammonium, m _2. ]

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing concrete using a concrete composition having high fluidity and having few air bubbles generated on a concrete surface after hardening.

[0002]

2. Description of the Related Art Polyalkylene glycol monoester copolymers have been developed as admixtures for improving the fluidity of concrete compositions (JP-A-58-74552, JP-A-4-209737, Japanese Patent Application Laid-Open No. Hei 7-223852) has demanded suppression of air bubbles generated on the concrete surface after hardening from the viewpoint of aesthetic appearance.

To suppress such bubbles, a release agent using a specific unsaturated fatty acid or phospholipid in a mineral oil or the like in combination with a surfactant has been proposed (JP-A-5-69428,
JP-A-5-293812).

However, the ability of the release agent to suppress air bubbles varies depending on the admixture added to the concrete, and the above-mentioned release agent is still insufficient for concrete containing the polyalkylene glycol monoester copolymer as an admixture.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to improve the surface appearance of concrete obtained by using the concrete composition containing the polyalkylene glycol monoester copolymer.

[0006]

According to the present invention, there is provided a compound represented by the general formula (A):
And at least one monomer (b) selected from the compounds represented by the general formulas (B) and (C)
And a concrete composition containing a copolymer obtained by polymerizing a monomer mixture containing sorbitan fatty acid ester as a main component and applying a mineral oil containing no phospholipids and unsaturated fatty acids. This is a method for producing concrete that is filled and hardened.

[0007]

Embedded image

Wherein R ₁ and R _{2 are} hydrogen atoms or methyl groups m ₁ is an integer of 0 to 2 AO is an oxyalkylene group having 2 to 3 carbon atoms n is a number of 2 to 300 X is a hydrogen atom or carbon atom And represents an alkyl group represented by Formulas 1 to 3. ]

[0009]

Embedded image

[Wherein R ₃ and R _{6 are} hydrogen atoms or methyl groups R ₄ and R _{5 are} hydrogen atoms, methyl groups or M ₂ O (CO) (CH ₂ ) m ₂ M ₁ , M ₂ , Y: shows 0-2 integers of: a hydrogen atom, an alkali metal, alkaline earth metal, ammonium, hydroxyl mono substituted, di-, trialkylammonium m _2. ]

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The copolymer used in the present invention comprises an alkylene oxide having 2 to 3 carbon atoms in an average addition mole number of 2
It is an addition of up to 300 moles and provides excellent fluidity to the concrete composition. As the monomer (a) represented by the general formula (A), an esterified product of a polyalkylene glycol having a lower alkyl group blocked at one end such as methoxypolyethylene glycol, methoxypolypropylene glycol, ethoxypolyethylene polypropylene glycol and (meth) acrylic acid And ethylene oxide (EO) and propylene oxide (PO) for (meth) acrylic acid
Adducts are preferably used. The additional form may be any of single, random, block or alternating. More preferred is an esterified product of methoxypolyethylene glycol and (meth) acrylic acid. The average number of moles of polyalkylene glycol added is preferably 110 to 200 in order to obtain excellent fluidity. It should be noted that a mixture of two or more monomers having different average addition mole numbers and the like may be used.

The monomer (b) represented by the general formula (B) includes unsaturated monocarboxylic acid monomers such as (meth) acrylic acid and crotonic acid, maleic anhydride, maleic acid, and itaconic anhydride. , Itaconic acid, unsaturated dicarboxylic acid monomers such as fumaric acid, or their alkali metal salts, alkaline earth metal salts, ammonium salts, mono-, di-, or trialkylammonium salts whose hydroxyl groups may be substituted Preferred and more preferred are (meth) acrylic acid and alkali metal salts thereof.

As the monomer (b) represented by the general formula (C), allyl sulfonic acid, methallyl sulfonic acid, or an alkali metal salt, an alkaline earth metal salt, an ammonium salt, or a hydroxyl group thereof is substituted. Mono, di, trialkyl ammonium salts which may be used are used.

The reaction units of the monomers (a) and (b) constituting the copolymer are as follows: (a) / (b) = 1/100 to 100 /
100 (molar ratio) is preferable because of excellent fluidity. More preferably, (a) / (b) = 5/100 to 50/100 (molar ratio).

The monomers (a) and (b) in the copolymer
Is at least 50% by weight, particularly at least 80% by weight, and
0% by weight is preferred. The monomers other than the monomers (a) and (b) include, for example, monomers of the formula (A) wherein n is from 1 to less than 30, acrylonitrile, acrylate, (meth) acrylamide, styrene, styrene sulfonic acid And the like.

The weight average molecular weight of the copolymer is preferably in the range of 3,000 to 500,000 from the viewpoint of suppressing breathing,
A range of 00,000 is more preferred. The weight average molecular weight is determined by a gel permeation chromatography method (standard substance: sodium polystyrene sulfonate conversion).

The copolymer is described in, for example, JP-A-58-74552,
JP-A-4-209737 and JP-A-7-223852 are manufactured by the solution polymerization method. Specifically, in the presence of a polymerization initiator such as ammonium persulfate and hydrogen peroxide in water or a lower alcohol having 1 to 4 carbon atoms, if necessary, sodium bisulfite, mercaptoethanol, or the like is added, and 50 to 10 is added.
The reaction may be performed at 0 ° C. for 0.5 to 10 hours.

The above-mentioned copolymer has a unit cement content of 350
It is preferably added to a concrete of up to 600 kg / m ^{2 so} as to have a solid content of 0.01 to 3% by weight based on the cement.

According to the present invention, a concrete composition containing the above-mentioned copolymer is filled in a mold containing a sorbitan fatty acid ester and a mineral oil containing no phospholipids and unsaturated fatty acids, and cured. You. The sorbitan fatty acid ester is preferably a sorbitan ester of a saturated or unsaturated fatty acid having an alkyl group of 12 to 18, and has an HLB value (Griffin) of 1.0 to 9.0, preferably 1.5 to 5.0, particularly preferably for surface aesthetics. Specific preferred sorbitan fatty acid esters include sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan sesquioleate, and the like.

Mineral oils to which these sorbitan fatty acid esters are added include spindle oil, machine oil, trans oil,
There is no particular limitation with silicone oil or the like. The addition amount is preferably 1 to 20 parts by weight based on 100 parts by weight of the mineral oil for the surface aesthetics. However, if it contains phospholipids or unsaturated fatty acids,
The bubble suppressing ability of the concrete composition containing the copolymer becomes insufficient.

The method of applying the above-mentioned mineral oil to a mold is suitably applied by mop coating or spraying, but is not limited thereto, and it can also be applied to a mold other than metal. Concrete is not limited to civil engineering, architecture, secondary products, etc., but includes all concrete using formwork. The same applies to the type of concrete, and the concrete can be used in a wide range from zero-slump super-hard concrete to non-vibration concrete such as high-flowable, non-separable concrete.

The concrete composition which is the object of the present invention is mainly composed of cement, fine aggregate and coarse aggregate, but uses various admixtures such as blast furnace slag, fly ash, silica sand and silica fume. You can also. Furthermore,
Known additives (materials), for example, AE agent, AE water reducing agent, high performance water reducing agent, retarder, early strength agent, accelerator, foaming agent, foaming agent,
An antifoaming agent, a thickener, a waterproofing agent, an antifoaming agent and the like can be used in combination.

[0023]

EXAMPLES Illustrative examples of the synthesis of copolymer 4 in Table 1 are shown below. A reaction vessel was charged with 15 mol of water, and a mixture of 0.35 mol of the monomer (a) of copolymer 4, 1 mol of methacrylic acid, and 15 mol of water mixed and dissolved in a nitrogen atmosphere at 75 ° C., 0.01 mol of a 20% aqueous ammonium persulfate solution , And 4 g of 2-mercaptoethanol are simultaneously added dropwise over 2 hours. Next, 0.03 mol of a 20% aqueous ammonium persulfate solution was added dropwise in 30 minutes, and the temperature was raised to 95 ° C. for 1 hour at the same temperature, and then 12 g of 35% hydrogen peroxide solution was added.
And ripen for 2 hours. After the completion of the aging, a 48% aqueous sodium hydroxide solution was added to neutralize the solution to obtain a copolymer having a molecular weight of 45,000.

Table 1 shows the compositions and molecular weights of the obtained copolymers 1 to 8.

[0025]

[Table 1]

The symbols and contents of the admixtures used as comparative examples are as follows.

NS: Naphthalenesulfonic acid-based dispersant (Mighty 150 manufactured by Kao Corporation) MS: Melaminesulfonic acid-based dispersant (Mighty 150V-2 manufactured by Kao Corporation) Evaluation method Components 1 to 9 shown in Table 2 were used. 7.5 parts by weight of 100 parts by weight of 4,6 machine oil (manufactured by Cosmo Oil Co., Ltd.) was mixed and dissolved, and this was applied as a release agent to a steel mold of Φ10 × 20 cm with a brush.

In the concrete composition shown in Table 3, the materials and the copolymer shown in Table 1 were kneaded by a forced mixer for 90 seconds, and the amount of the copolymer was adjusted so that the fluidity (slump value) became 18 ± 1 cm. did. The measurement of the slump value conformed to the JIS-A1101 method. The prepared concrete composition was filled in a mold to which the above-mentioned release agent was applied, and was vibrated with a table vibrator (2500 r / m × 0.3 mm amplitude) for 30 seconds. After standing for 24 hours, the number of bubbles of 1 mm or more per 100 cm ² of the surface of the concrete removed from the mold was measured. Table 4 shows the results.

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

[0032]

According to the present invention, the surface appearance of concrete obtained by using a concrete composition to which a polyalkylene glycol monoester copolymer having a large fluidity-imparting effect is added is improved, and rationalization by reducing repairs is achieved. Can be expected.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 24:26) 103: 32

Claims (5)

(57) [Claims] 1. A monomer (a) represented by the general formula (A) and one or more monomers (b) selected from the compounds represented by the general formulas (B) and (C) And a concrete composition containing a copolymer obtained by polymerizing a monomer mixture containing sorbitan fatty acid ester as a main component and a mineral oil containing no phospholipid and unsaturated fatty acid. Method of filling concrete and curing it. Embedded image [In the formula, R ₁ , R ₂ : hydrogen atom or methyl group m ₁ : an integer of 0 to 2 AO: an oxyalkylene group having 2 to 3 carbons n: a number of 2 to 300 X: a hydrogen atom or 1 to 2 carbon atoms 3 represents an alkyl group. ] [Wherein, R ₃ , R ₆ : hydrogen atom or methyl group R ₄ , R ₅ : hydrogen atom, methyl group or M ₂ O (CO) (CH ₂ ) m ₂ M ₁ , M ₂ , Y: hydrogen atom, shows 0-2 integers of: alkali metal, alkaline earth metal, ammonium, hydroxyl mono substituted, di-, trialkylammonium m _2. ] 2. The sorbitan fatty acid ester having an HLB value of 2.
2. The method according to claim 1, wherein the ratio is 1.0 to 9.0. 3. The method according to claim 1, wherein the mineral oil contains only a sorbitan fatty acid ester. 4. A sorbitan fatty acid ester comprising 100 mineral oils.
The method according to any one of claims 1 to 3, wherein the amount is 1 to 20 parts by weight based on parts by weight. 5. The monomer (a) constituting the copolymer
The reaction unit of (b) is (a) / (b) = 1/100 to 100 /
The method according to any one of claims 1 to 4, wherein the molar ratio is 100 (molar ratio) and the weight average molecular weight of the copolymer is 3,000 to 500,000.