JP3443454B2 - Cement additive for grouting method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement additive for a grout method in an underground method for improving soft ground. More specifically, the present invention relates to a cement additive used in a method of injecting a cement-based hardening agent to form a hardening body while cutting soft ground with an ultra-high pressure jet liquid (jet).

[0002]

^2. Description of the Related Art The grout method is a method in which a cement-based hardening material is sent as a jet fluid at high pressure (50 to 700 kg / cm ² ) through a pipe through which a hole of about 15 cm is drilled from above ground to deep underground. This is an improvement method for soft ground where the pillars and walls are constructed by excavating the earth and sand and discharging it to the ground while replacing it with a hardening material.

[0003] The cement hardening material with high fluidity is used in this method.
(Hereinafter, referred to as a curing material) is required,
As an agent for this purpose, a naphthalene sulfonate formaldehyde condensate (hereinafter referred to as "condensation product" that satisfies the strength by water / cement ratio (strength after 28 days = 30 kg / cm ² or more) and has a fluidizing effect
Naphthalene type) is used as an additive.

[0004]

Further, in this method, a part of the hardening material to be injected as a jet jet fluid needs to be mixed with the cut earth and sand and passed through a pipe to be discharged to the ground. As a result, the action of lowering the viscosity of the sludge is required.

However, although the conventional naphthalene-based additive has a large ability to reduce the viscosity of the hardening material at the time of injection, the viscosity of the clay mud is small, so that the viscosity of the sludge is not lowered and the discharge is difficult. Is. As a result, not only the efficiency of injecting the curing material decreases, but also the curing material causes problems such as diffusion outside the design in the soil and accompanying protrusions to the surface layer.

[0006]

[Means for Solving the Problems] In view of the above problems, the present inventors have both the high fluidity of a hardened material and the ability to reduce the viscosity of clay, and have a standard strength (strength after 28 days = 30 kg). / c
As a result of earnest studies aiming at an additive satisfying (m ² or more), it was found that a dispersant skeleton having an alkylene oxide having a large water retention capacity is effective for dispersion of cement and clay, and focusing on the alkylene oxide chain. As a result of research, they have found that the alkylene oxide chain length is extremely effective at high addition mole numbers in the range of 110 to 300 moles, and completed the present invention.

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). The present invention relates to a cement additive for a grout method, which contains a copolymer (a) obtained by polymerizing the above monomer (b) as an essential component.

[0008]

[Chemical 3]

(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 2 to 3 carbon atoms n is an integer of 110 to 300 and X is hydrogen or 1 carbon atom. ~ Represents an alkyl group of 3.)

[0010]

[Chemical 4]

(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, alkylammonium or substituted alkylammonium m ₂ : represents an integer of 0 to 2. ) Further, the present invention is a monomer represented by the above general formula (A)
a copolymer (a) obtained by polymerizing (a) with at least one monomer (b) selected from the compounds represented by the above general formulas (B) and (C); The present invention relates to a cement additive for a grout method, which contains, as an essential component, at least one compound (b) selected from the group consisting of carboxylic acid or a salt thereof, sugar and sugar alcohol.

The copolymer (a) used in the present invention is a copolymer of a polyalkylene glycol monoester monomer having an unsaturated bond with a similar structure and an acrylic acid-based and / or unsaturated dicarboxylic acid-based monomer. Known patents for polymers
(Japanese Patent Publication No. 59-18338, Japanese Patent Publication No. 2-78978, Japanese Patent Publication No. 2-7898, Japanese Patent Publication No. 2-7901, Japanese Patent Publication No. 211542, Japanese Patent Laid-Open No. 3-75252, Japanese Patent Publication No.
59-162163). However, even if the polycarboxylic acid salt having these alkylene chains is used as a cement additive for the grout method, the viscosity of the clay is not sufficiently reduced.

As a result of various studies on the chain length of the oxyalkylene group, the present inventors have found that the cement and clay have extremely high viscosity reducing in a high chain length (additional mole number = 110 to 300) range of a specific region. Is found. That is,
When the number of moles of ethylene oxide and / or propylene oxide is in the range of 2 to 100 moles as in the known patents (the patents relating to the above-mentioned copolymers), a sufficient effect cannot be exhibited.

In the copolymer (a) of the present invention, the general formula
Examples of the monomer (a) represented by (A) include methoxy polyethylene glycol, methoxy polyethylene polypropylene glycol, ethoxy polyethylene glycol, ethoxy polyethylene polypropylene glycol, propoxy polyethylene glycol, propoxy polyethylene polypropylene glycol, and the like. An esterification product of glycol with a dehydrogenation (oxidation) reaction product of acrylic acid, methacrylic acid or a fatty acid, or an ethylene oxide or propylene oxide adduct to a dehydrogenation (oxidation) reaction product of acrylic acid, methacrylic acid or a fatty acid is used. The number of moles of polyalkylene glycol added is 110
It is up to 300, and both additions of ethylene oxide and propylene oxide can be carried out by random addition, block addition, alternating addition and the like. When the number of added moles of polyalkylene glycol is less than 110, the viscosity of the clay is not sufficiently lowered, and when it exceeds 300, the fluidity of the cement 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.

Monomers constituting the copolymer (a) of the present invention
The reaction unit of (a) and monomer (b) is monomer (a) / monomer
In particular, the range of (b) = 0.1 / 100 to 100/100 (molar ratio) is
Excellent clay viscosity reduction and cement fluidity. When the above molar ratio is less than 0.1 / 100, the clay viscosity tends to decrease, and when it exceeds 100/100, the fluidity of the cement 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 high, the fluidity of the cement will decrease, and if the molecular weight is too low, the viscosity reduction of the clay 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.

Furthermore, by essentially adding two components of the copolymer (a) in the present invention and one or more compounds (b) selected from the group consisting of oxycarboxylic acid or a salt thereof, sugar and sugar alcohol. , And found that the viscosity of clay is further increased.

As the oxycarboxylic acid, gluconic acid,
Examples include glucoheptonic acid, arabonic acid, malic acid or citric acid. Examples of these salts include inorganic or organic salts such as sodium, potassium, calcium, magnesium, ammonium and triethanolamine. Examples of sugars include monosaccharides such as glucose, fructose, galactose, mannose, xylose, arabitolose, repose and isomerized sugar, oligosaccharides such as disaccharide and trisaccharide, and polysaccharides such as dextrin. Moreover, molasses containing these is also included. Furthermore, examples of the sugar alcohol include sorbitol.

The addition amount of the copolymer (a) of the present invention is about 0.1 to 3.0% by weight based on the solid content of the cement, and 0.2 to 0.5% by weight is preferably used.

One or more compounds selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols
When (B) is used in combination, the compounding ratio of the copolymer (A) and the compound (B) is (A) / (B) = 100 / 0.01 to 5.
It is about 0 (weight ratio of solid content), and 100 / 0.1 to 1.0 is preferably used. If it is less than 100 / 0.01, the viscosity reduction of the clay tends to decrease, and if it exceeds 100 / 5.0, the curing time tends to be delayed, which is not preferable.

When the copolymer (a) and the compound (b) are added together, the copolymer (a) and the compound (b) are previously added.
It is possible to add a mixture of the above compounds or to add them separately, without any limitation.

The additive of the present invention is to be added to a cement-based hardening material, and as the cements, in addition to ordinary Portland cement, cements such as blast furnace cement, fly ash cement and early strength cement are targeted. . In addition to cement, various admixtures such as fly ash, blast furnace slag, silica fume, and hardeners including expansive materials can also be used and are not limited.

Further, the additives of the present invention include other known additives such as 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 and a defoaming agent. Foaming agents, thickening agents, waterproofing agents, antifoaming agents and the like can be mentioned.

[0031]

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 addition mol number = 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 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-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 for admixture) 10 mol of water was charged into a reaction vessel equipped with a stirrer, and 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 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
0.045 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 for 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, 0.002 mol of 20% ammonium persulfate aqueous solution, and 2-mercaptoethanol 0.6
g of each of the three is simultaneously added dropwise to the reaction system over 2 hours. Next, 0.006 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., 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 of admixture) 30 mol of water was charged into a reaction vessel equipped with a stirrer, and 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 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-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 as an 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
Manufactured by Kao Co., Ltd. Table 1 shows the contents and symbols of the compounds (b) used in the examples.

[0049]

[Table 1]

Evaluation Method of Concrete Test A hardening material and a clay material were prepared with the composition shown in Table 2, and the fluidity was measured by adding the additive of the present invention and the comparative additive. Further, a hardening material containing additives was added to the clay substance to measure viscosity and strength. The strength is assumed to be the strength in a soil state in which a clay material and a hardening material are mixed, and in this example, the hardening material and the clay material were assumed to be 1 to 2 (weight ratio).

[0051]

[Table 2]

The measurement was carried out by the method shown below.・ Fluidity of hardened material; J
It was expressed as the time (seconds) required to flow down from the funnel. -Viscosity obtained by mixing a hardener and a clay substance; expressed in "cps" using a B-type viscometer. -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 target performance requirements are shown below.・ Flowability of hardened material: 18 seconds or less ・ Viscosity of hardened material + clay; 5000 cps or less ・ Compressive strength: 30 kg / cm ² or more.

The test results are shown in Table 3.

[0055]

[Table 3]

Evaluation results As shown in Table 3, by using the additive of the present invention, both the high fluidity and the viscosity reducing property for clay are obtained, and the standard strength (strength after 28 days = 30 kg / cm ² or more) is obtained. It is possible to obtain a hardened material that satisfies Further, since the injection work can be improved, it can contribute to the development of the ground improvement method by the high pressure injection method in the future.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C04B 24/10 C04B 24/10 24/38 24/38 Z 28/02 28/02 C09K 17/10 C09K 17/10 H 17 / 44 17/44 H // C07C 309/04 C07C 309/04 C08F 290/06 C08F 290/06 C04B 103: 40 C04B 103: 40 111: 70 111: 70

Claims (8)

(57) [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) as an essential component Cement additive for grout method. [Chemical 1] (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. The cement additive for the grout method according to claim 1, which further comprises at least one compound (b) selected from the group consisting of oxycarboxylic acid or a salt thereof, sugar and sugar alcohol. 3. A monomer (a) constituting the copolymer (a),
The reaction unit of monomer (b) is monomer (a) / monomer (b) =
The cement additive for the grout method according to claim 1 or 2, which is 0.1 / 100 to 100/100 (molar ratio). 4. The grout method 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. Cement additive. 5. The compounding ratio of the copolymer (a) and the compound (b) is (a) / (b) = 100 / 0.01 to 5.0 (solid content weight ratio).
The cement additive for the grout method according to any one of claims 2 to 4. 6. The cement additive for the grout method according to claim 2, wherein the oxycarboxylic acid is gluconic acid, glucoheptonic acid, arabonic acid, malic acid or citric acid. 7. The grout method according to any one of claims 2 to 6, wherein the sugar is a monosaccharide, an oligosaccharide or a polysaccharide .
Cement additive . 8. The cement for grouting method according to claim 2, wherein the sugar alcohol is sorbitol.
Additives .