JP6822360B2 - Hydraulic composition - Google Patents

Description

The present invention relates to a hydraulic composition, and more specifically to a hydraulic composition having excellent frost damage resistance and less bleeding.

Water-soluble cellulose ether is used for material separation resistance, bleeding reduction effect, fluidity imparting, etc. of hydraulic compositions such as concrete.
However, in the hydraulic composition to which the water-soluble cellulose ether is added, air bubbles are entrained during kneading of the hydraulic composition due to the surface-active action of the water-soluble cellulose ether, so that the amount of air in the hydraulic composition becomes excessive. It may end up.
Since the bubble diameter of the entrained air produced by the water-soluble cellulose ether is large and the bubbles are not effective for frost damage resistance, an operation of removing coarse bubbles is performed by using a defoaming agent.

Further, in order to ensure the frost damage resistance of the hydraulic composition, it is necessary to entrain fine bubbles having a diameter of about 25 to 250 μm in the hydraulic composition, and an AE agent which is an air entraining agent is usually used. To.
As described above, in the case of a water-hard composition using a water-soluble cellulose ether, it is necessary to use a defoaming agent for the purpose of defoaming the entrained air derived from the water-soluble cellulose ether to obtain a predetermined amount of air. Since the defoaming agent defoams not only the entrained air derived from the water-soluble cellulose ether but also the fine bubbles derived from the AE agent, it is difficult to satisfy the frost damage resistance.

In response to the above problems, for example, the use of O-2,3-dihydroxypropyl cellulose having low air entrainment as a water-soluble cellulose ether has been proposed (Patent Document 1).
Further, a method of using hollow microspheres instead of the AE agent has also been proposed (Patent Document 2).
Further, a useful AE agent has been proposed for cement compositions using fly ash (Patent Document 3).

Japanese Unexamined Patent Publication No. 6-206752 Japanese Unexamined Patent Publication No. 8-59327 Japanese Unexamined Patent Publication No. 8-59320

However, in the method of Patent Document 1, even if the frost damage resistance can be satisfied by using O-2,3-dihydroxypropyl cellulose, the viscosity increase in the water-hard composition is insufficient, so that the material separation resistance is increased. The bleeding reduction effect and the fluidity imparting effect may be inferior to those of ordinary cellulose ether.
On the other hand, in the method of Patent Document 2, since the air amount fluctuates greatly for each batch, it may be difficult to control the air amount, and further, the hollow microspheres are expensive, which may increase the cost. ..
Further, the method of Patent Document 3 is not sufficient in terms of bleeding, air volume retention, and the like.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydraulic composition containing an AE agent and a water-soluble cellulose ether, which has excellent frost damage resistance and less bleeding.

As a result of diligent studies to achieve the above object, the present inventors can obtain a hydraulic composition having excellent frost damage resistance and less bleeding by using a specific AE agent and a water-soluble cellulose ether. We found that and completed the present invention.

（式中、Ｒ¹は、炭素数１２〜２４のアルキル基またはアルケニル基を表す。）

（式中、Ｒ²は、炭素数８または９のアルキル基を表し、ｎは、１〜５０の整数を表す。）
２． 前記水溶性セルロースエーテルが、ヒドロキシプロピルメチルセルロースまたはヒドロキシエチルメチルセルロースである１の水硬性組成物、
３． 前記ヒドロキシプロピルメチルセルロースにおける非メトキシ基置換ヒドロキシプロピル基のモル分率（Ｂ）に対するメトキシ基置換ヒドロキシプロピル基のモル分率（Ａ）の比（Ａ／Ｂ）が、０．２〜１．０である２の水硬性組成物、
４． 前記ヒドロキシエチルメチルセルロースにおける非メトキシ基置換ヒドロキシエチル基のモル分率（Ｂ）に対するメトキシ基置換ヒドロキシエチル基のモル分率（Ａ）の比（Ａ／Ｂ）が、２．０〜３．０である２の水硬性組成物、
５． 前記ＡＥ剤が、前記セメントに対して０．０００１〜０．５質量％含まれる１〜４のいずれかの水硬性組成物、
６． 気泡間隔係数が、２５〜２５０μｍである１〜５のいずれかの水硬性組成物
を提供する。 That is, the present invention
1. 1. The AE agent contains at least an AE agent, a water-soluble cellulose ether, a defoaming agent, cement, water and an aggregate, and the AE agent is a fatty acid represented by the following general formula (1) and represented by the following general formula (1). A fatty acid-based surfactant consisting of an alkali metal salt of a fatty acid, a lower alkylamine salt of a fatty acid represented by the following general formula (1), or a lower alkanolamine salt of a fatty acid represented by the following general formula (1), and the following. A water-hard composition comprising a nonionic surfactant composed of a polyoxyethylene phenyl ether represented by the general formula (2).

(In the formula, R ¹ represents an alkyl group or an alkenyl group having 12 to 24 carbon atoms.)

(In the formula, R ² represents an alkyl group having 8 or 9 carbon atoms, and n represents an integer of 1 to 50.)
2. 2. The hydraulic composition of 1 in which the water-soluble cellulose ether is hydroxypropylmethyl cellulose or hydroxyethyl methyl cellulose,
3. 3. The ratio (A / B) of the mole fraction (A) of the methoxy group-substituted hydroxypropyl group to the mole fraction (B) of the non-methoxy group-substituted hydroxypropyl group in the hydroxypropylmethyl cellulose is 0.2 to 1.0. There are 2 water-hardening compositions,
4. The ratio (A / B) of the mole fraction (A) of the methoxy group-substituted hydroxyethyl group to the mole fraction (B) of the non-methoxy group-substituted hydroxyethyl group in the hydroxyethyl methyl cellulose is 2.0 to 3.0. There are 2 water-hardening compositions,
5. The hydraulic composition according to any one of 1 to 4, wherein the AE agent is contained in an amount of 0.0001 to 0.5% by mass based on the cement.
6. A hydraulic composition according to any one of 1 to 5 having a bubble spacing coefficient of 25 to 250 μm is provided.

According to the present invention, it is possible to provide a hydraulic composition having excellent frost damage resistance and less bleeding.

Hereinafter, the present invention will be specifically described.
The water-hardening composition of the present invention contains at least an AE agent, a water-soluble cellulose ether, a defoaming agent, cement, water and an aggregate, and the AE agent is a fatty acid represented by the following general formula (1), the following general. It consists of an alkali metal salt of a fatty acid represented by the formula (1), a lower alkylamine salt of a fatty acid represented by the following general formula (1), or a lower alkanolamine salt of a fatty acid represented by the following general formula (1). It is characterized by containing a fatty acid-based surfactant and a nonionic surfactant composed of a polyoxyethylene phenyl ether represented by the following general formula (2).

In the above general formula (1), the alkyl group or alkenyl group having 12 to 24 carbon atoms of R ¹ may be either a straight chain or a branched chain.
Specific examples of the fatty acid represented by the general formula (1) include myristic acid (14 carbon atoms, R ¹ : 13 carbon atoms), pentadecyl acid (15 carbon atoms, R ¹ : 14 carbon atoms), and palmitic acid (carbon). Number 16, R ¹ : 15 carbons), margaric acid (17 carbons, R ¹ : 16 carbons), stearic acid (18 carbons, R ¹ : 17 carbons), oleic acid (18 carbons: R ¹⁾ : 17 carbon atoms, 1 double bond), linoleic acid (18 carbon atoms: R ¹ : 17 carbon atoms, 2 double bonds), linolenic acid (18 carbon atoms: R ¹ : 17 carbon atoms, double bond The number 3) and the like can be mentioned.
Specific examples of the alkali metal salt of the fatty acid represented by the formula (1) include sodium and potassium, and specific examples of the lower alkylamine salt of the fatty acid include triethylamine salt and diisopropylethylamine salt. Specific examples of lower alkanolamine salts of fatty acids include monoethanolamine salts and triethanolamine salts.
In particular, as the fatty acid-based surfactant, tall oil fatty acid saponified product, oleic acid saponified product, and linoleic acid saponified product, which are a mixture of oleic acid, linoleic acid, palmitic acid and stearic acid, are preferable, and tall oil fatty acid saponified product is more preferable. preferable. As the saponified product, a sodium saponified product is preferable.

On the other hand, in the nonionic surfactant of the general formula (2), the alkyl group having 8 or 9 carbon atoms of R ² may be either a straight chain or a branched chain.
Examples of the linear alkyl group having 8 or 9 carbon atoms include an n-octyl group and an n-nonyl group.
Examples of the alkyl group having 8 or 9 carbon atoms in the branched chain include an isooctyl group and an isononyl group.
Specific examples of the nonionic surfactant include polyoxyethylene phenyl ethers such as polyoxyethylene nonyl phenyl ether and polyoxyethylene octyl phenyl ether.
The number of moles (n) of ethylene oxide added is 1 to 50 from the viewpoint that the air entrainment performance can be improved and the amount of the AE agent used can be reduced, but the solubility in water is lowered. Considering the tendency, 20 to 30 is preferable.

The AE agent used in the present invention may contain at least the fatty acid-based surfactant and the nonionic surfactant. If only one of the fatty acid-based surfactant and the nonionic surfactant is used, the bubble spacing coefficient of the hydraulic composition becomes larger than 250 μm, so that sufficient frost damage resistance cannot be obtained.
The ratio of the fatty acid-based surfactant to the nonionic surfactant used in the AE agent is preferably a mass ratio of fatty acid-based surfactant: nonionic surfactant = 1 to 99: 99 to 1, more preferably 20 to 80. : 80 to 20, even more preferably 40 to 60:60 to 40.
The amount of the AE agent used varies depending on the desired amount of air and the type of material used for the hydraulic composition, but is preferably 0.0001 to 0.5% by mass, more preferably 0.001 to 0, based on the cement. .3% by mass.

Examples of the water-soluble cellulose ether include hydroxypropylmethyl cellulose and hydroxyethyl methyl cellulose. The water-soluble cellulose ether is preferably nonionic, and can be used alone or in combination of two or more depending on the purpose.
In hydroxypropylmethylcellulose, the degree of substitution (DS) of the methoxy group is preferably 1.0 to 2.2, more preferably 1.3 to 1.9, and the number of molar substitutions (MS) of the hydroxypropoxy group is preferably. It is 0.1 to 0.6, more preferably 0.1 to 0.5.
In hydroxyethyl methyl cellulose, the degree of substitution (DS) of the methoxy group is preferably 1.0 to 2.2, more preferably 1.3 to 1.9, and the number of moles of substitution (MS) of the hydroxyethoxy group is preferably. It is 0.1 to 0.6, more preferably 0.2 to 0.4.
The degree of substitution of the alkyl group and the number of moles of the hydroxyalkyl group in the water-soluble cellulose ether can be determined by converting the values that can be measured by the method for analyzing the degree of substitution of hypromellose (hydroxypropyl methylcellulose) described in the 17th revised Japanese Pharmacopoeia. be able to.

In hydroxypropylmethyl cellulose, the ratio (A / B) of the mole fraction (A) of the methoxy group-substituted hydroxypropyl group to the mole fraction (B) of the non-methoxy group-substituted hydroxypropyl group is preferable from the viewpoint of maintaining the amount of air. Is 0.2 to 1.0, more preferably 0.3 to 0.8, and even more preferably 0.3 to 0.7.
In hydroxyethyl methyl cellulose, the ratio (A / B) of the mole fraction (A) of the methoxy group-substituted hydroxyethyl group to the mole fraction (B) of the non-methoxy group-substituted hydroxyethyl group is preferable from the viewpoint of maintaining the amount of air. Is 2.0 to 3.0, more preferably 2.2 to 2.8.

The molar fraction (A) of the methoxy group-substituted hydroxyalkyl group in which the hydroxyl group of the hydroxyalkyl group (hydroxypropyl group, hydroxyethyl group) is further substituted with a methoxy group, and the non-methoxy group-substituted hydroxyalkyl group not substituted with a methoxy group. As a method for analyzing the molar fraction (B) of a group, as described in Marcomolecules, 20, 2413 (1987) and Journal of the Textile Society, 40, T-504 (1984), water-soluble hydroxyalkylalkylcellulose. Is hydrolyzed in sulfuric acid, neutralized, then reduced with sodium boron hydride, and then filtered and purified to be acetylated using ¹³ C-NMR, liquid chromatography, or gas chromatography and a mass analyzer. The temperature is raised by 2.5 ° C. per minute from 150 to 280 ° C., maintained at 280 ° C. for 10 minutes, and can be determined from the characteristics of each identified detection graph.
The mole fractions (A) and (B) of the present invention were calculated for a hydroxyalkyl group in which only one molecule was substituted for any one of the hydroxyl groups at the 2, 3 and 6 positions of each glucose ring. Therefore, if any of the hydroxyl groups at the 2, 3 and 6 positions of the glucose ring is already substituted with a hydroxyalkyl group and the hydroxyl group of the hydroxyalkyl group is further substituted with a hydroxyalkyl group, the mole fraction (A). ) And (B) are not included in the calculation.

The viscosity of the 2% by mass aqueous solution of the water-soluble cellulose ether at 20 ° C. is preferably 10 to 200,000 mPa · s, more preferably 50 to 100,000 mPa at 20 rpm of the BH type viscometer from the viewpoint of reducing bleeding. · S, even more preferably 100-50,000 mPa · s.
The amount of the water-soluble cellulose ether added is preferably 0.01 to 5 kg, more preferably 0.05 to ³ kg, still more preferably 0.1 per 1 m ^{3 of the} hydraulic composition from the viewpoint of reducing bleeding and fluidity. It is ~ 2 kg.

Examples of the defoaming agent include oxyalkylene-based, silicone-based, alcohol-based, mineral oil-based, fatty acid-based, and fatty acid ester-based defoaming agents.
Specific examples of the oxyalkylene-based defoaming agent include polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adduct; diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, and polyoxyethylene poly. (Poly) oxyalkylene alkyl ethers such as oxypropylene 2-ethylhexyl ether, higher alcohol having 8 or more carbon atoms and secondary alcohol having 12 to 14 carbon atoms and oxyethylene oxypropylene adduct; polyoxypropylene phenyl ether, poly (Poly) oxyalkylene (alkyl) aryl ethers such as oxyethylene nonylphenyl ether; 2,4,7,9-tetramethyl-5-decine-4,7-diol, 2,5-dimethyl-3-hexin- Acetylene ethers obtained by addition-polymerizing alkylene oxide to acetylene alcohol such as 2,5-diol, 3-methyl-1-butin-3-ol; diethylene glycol oleic acid ester, diethylene glycol lauric acid ester, ethylene glycol distearate, poly (Poly) oxyalkylene fatty acid esters such as oxyalkylene oleic acid ester; (Poly) oxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolauric acid ester and polyoxyethylene sorbitan trioleic acid ester; Polyoxypropylene methyl ether sulfate (Poly) oxyalkylene alkyl (aryl) ether sulfate esters such as sodium and polyoxyethylene dodecylphenol ether sodium sulfate; (poly) oxyalkylene alkyl phosphate esters such as (poly) oxyethylene stearyl phosphate; polyoxy (Poly) oxyalkylene alkyl amines such as ethylene lauryl amine; polyoxyalkylene amide and the like can be mentioned.

Specific examples of the silicone-based defoaming agent include dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane), fluorosilicone oil and the like.
Specific examples of the alcohol-based antifoaming agent include octyl alcohol, 2-ethylhexyl alcohol, hexadecyl alcohol, acetylene alcohol, glycols and the like.
Specific examples of the mineral oil-based defoaming agent include kerosene and liquid paraffin.
Specific examples of the fatty acid-based antifoaming agent include oleic acid, stearic acid, and alkylene oxide adducts thereof.
Specific examples of the fatty acid ester antifoaming agent include glycerin monolithinolate, an alkenyl succinic acid derivative, sorbitol monolaurate, sorbitol trioleate, and natural wax.
Among these, in the present invention, it is preferable to use an oxyalkylene-based defoaming agent from the viewpoint of defoaming performance.

From the viewpoint of controlling the amount of air, the amount of the defoaming agent added is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass, and even more preferably 1 to 2% by mass with respect to the water-soluble cellulose ether. It is 10% by mass.

Examples of cement include various types of cement such as ordinary Portland cement, early-strength Portland cement, moderate-heat Portland cement, blast furnace cement, silica cement, fly ash cement, alumina cement, and ultra-early-strength Portland cement.
From the viewpoint of ensuring strength, the cement content is preferably 270 to 800 kg per 1 m ³ of concrete when the hydraulic composition is concrete, and preferably 270 to 800 kg per 1 m ³ of mortar when the hydraulic composition is mortar. Is 300 to 1,000 kg. Examples of concrete include ordinary concrete, high-fluidity concrete, and medium-fluidity concrete, and examples of mortar include tile-attached mortar, repair mortar, and self-leveling material.
Examples of water include tap water and seawater, but tap water is preferable from the viewpoint of salt damage.

The water / cement ratio (% by mass) in the hydraulic composition is preferably 30 to 75% by mass, more preferably 45 to 65% by mass, from the viewpoint of material separation.
Aggregates include fine aggregates and coarse aggregates.
As the fine aggregate, river sand, mountain sand, land sand, crushed sand and the like are preferable.
The particle size (maximum particle size) of the fine aggregate is preferably 5 mm or less.
As the coarse aggregate, river gravel, mountain gravel, land gravel, crushed stone and the like are preferable.
The particle size (maximum particle size) of the coarse aggregate is larger than the particle size of the fine aggregate, preferably 40 mm or less, and more preferably 25 mm or less.

The content of the fine aggregate is preferably 400 to 1,100 kg, more preferably 500 to 1,000 kg per 1 m ^{3 of} concrete when the hydraulic composition is concrete, and when the hydraulic composition is mortar. Is preferably 500 to 2,000 kg, more preferably 600 to 1,600 kg per 1 m ^{3 of} mortar.
When the hydraulic composition is concrete, the content of the coarse aggregate is preferably 600 to 1,200 kg, more preferably 650 to 1,150 kg per 1 m ^{3 of} concrete.
When the hydraulic composition is concrete, the fine aggregate ratio (volume percentage) in the aggregate is preferably 30 to 55% by volume, more preferably 35 to 55 volumes, from the viewpoint of maintaining fluidity or sufficient strength. %, More preferably 35 to 50% by volume.
The fine aggregate ratio (volume%) = the volume of the fine aggregate / (volume of the fine aggregate + volume of the coarse aggregate) × 100.

A water reducing agent can be added to the hydraulic composition of the present invention as needed in order to obtain high fluidity retention with a small amount of water.
Examples of the water reducing agent include lignin-based, polycarboxylic acid-based, and melamine-based.
Specific examples of the lignin-based water reducing agent include lignin sulfonate and its derivatives.
Specific examples of the polycarboxylic acid-based water reducing agent include polycarboxylic acid ether-based, polycarboxylic acid ether-based and cross-linked polymer composite, polycarboxylic acid ether-based and oriented polymer composite, polycarboxylic acid ether-based and highly modified. Polymer complex, polyethercarboxylic acid-based polymer compound, maleic acid copolymer, maleic acid ester copolymer, maleic acid derivative copolymer, carboxyl group-containing polyether type, polycarboxylic acid group having terminal sulfone group Examples thereof include a compounding polymer, a polycarboxylic acid-based graft copolymer, a polycarboxylic acid-based compound, and a polycarboxylic acid ether-based polymer.
Specific examples of the melamine-based water reducing agent include a melamine sulfonic acid formarin condensate, a melamine sulfonate condensate, and a melamine sulfonate polyol condensate.

The amount of the water reducing agent added is preferably 0.01 to 5% by mass, more preferably 0.1 to 3% by mass, based on the cement, from the viewpoint of the fluidity of the hydraulic composition.
In order to secure a predetermined amount of air and obtain the durability of the hydraulic composition, other AE agents may be used in combination with the hydraulic composition, if necessary.
Examples of other AE agents include AE agents such as anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, and rosin surfactants.
Examples of the anionic surfactant system include a carboxylic acid type, a sulfate ester type, a sulfonic acid type, and a phosphoric acid ester type.
Examples of the cationic surfactant system include amine salt type, primary amine salt type, secondary amine salt type, tertiary amine salt type, and quaternary amine salt type.
Examples of the nonionic surfactant system include an ester type, an ester ether type, an ether type, and an alkanolamide type.
Examples of amphoteric surfactant systems include amino acid type and sulfobetaine type.
Examples of the rosin-based surfactant system include abietic acid, neo-avietic acid, palastolic acid, pimalic acid, isopimalic acid, dehydroabietic acid and the like.

In addition, in the hydraulic composition of the present invention, in order to control the physical properties of the hydraulic composition (fresh concrete or fresh mortar) immediately after kneading, a coagulation accelerator such as calcium chloride, lithium chloride, calcium formic acid and a citrate are used. A setting retarder such as sodium citrate or sodium gluconate can be used as needed.
Further, in order to prevent shrinkage cracks due to hardening / drying and cracks due to temperature stress due to the heat of hydration reaction of cement, an Auin-based or lime-based expansion material is added to the hydraulic composition of the present invention as necessary. can do.

The hydraulic composition of the present invention described above can be produced by a conventional method.
For example, first, a water-soluble cellulose ether, a defoaming agent, cement and an aggregate (fine aggregate, coarse aggregate) are put into a forced biaxial kneading mixer, and empty kneading is performed. Then, water, a water reducing agent and an AE agent are added and kneaded to obtain a hydraulic composition. The AE agent is used in consideration of the amount of the defoaming agent used so that the amount of air is 4.5 ± 1.5%.
In the present invention, the bubble spacing coefficient of the hydraulic composition is preferably 25 to 250 μm, more preferably 25 to 230 μm from the viewpoint of frost damage resistance. The bubble spacing coefficient can be measured by, for example, an air void analyzer (AVA; trade name) manufactured by German Instruments.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
[Material used]
(1) AE agent; listed in Table 1 (2) water-soluble cellulose ether; listed in Table 2 (3) defoaming agent 1; SN deformer 14HP, San Nopco oxyalkylene defoaming agent defoaming agent 2; AGITAN299, MUNZING CHEMIE GmbH oxyalkylene defoamer (4) Cement (C); ordinary Portland cement (made by Pacific cement), density; 3.16 g / cm ³
(5) Water (W); Tap water (6) Fine aggregate (S); Sand with a maximum particle size of 5 mm, produced in Shimonigorikawa, Myoko City, Niigata Prefecture, water absorption rate 2.79%, surface dry density 2.57 g / cm ³
(7) Coarse aggregate (G); gravel with a maximum particle size of 25 mm, produced in Shimonigorikawa, Myoko City, Niigata Prefecture, water absorption rate 1.45%, surface dry density 2.60 g / cm ³
(8) Water reducing agent 1; Master Pozoris No. 70, BASF Japan's lignin sulfonic acid and polyol complex water reducing agent 2; Master Leobuild 4000, BASF Japan's melamine sulfonic acid compound

[Examples 1 to 15 and Comparative Examples 1 to 5]
[Concrete kneading]
The water-soluble cellulose ether, defoaming agent, cement, fine aggregate and coarse aggregate shown in Table 2 were placed in a forced twin-screw kneading mixer having a capacity of 60 liters, and dry kneading was performed for 30 seconds. Then, water, a water reducing agent and an AE agent shown in Table 1 were added and kneaded for 90 seconds to obtain concrete having two kinds of formulations shown in Table 3 below. The mixing of concrete per batch was 40 liters.
The water-soluble cellulose ether was added in the amount shown in Table 4, the defoaming agent was used in an amount of 5% by mass with respect to the water-soluble cellulose ether, and the AE agent had an air content of 4.5 ± 1.5%. The amount of the water reducing agent added is Master Posolis No. In the case of 70, it was used so as to be 0.25% by mass with respect to cement, and in the case of Master Leobuild 4000, it was used so as to be 2.00% by mass with respect to cement.

配合１；普通コンクリート配合
配合２；高流動コンクリート配合

Formulation 1; Normal concrete formulation 2; High-fluidity concrete formulation

The concrete prepared in Examples 1 to 15 and Comparative Examples 1 to 5 was evaluated as follows. The results are shown in Tables 4-6. However, the evaluation of the air volume (A ₃₀ ) and the air volume retention ratio (A ₃₀ / A ₀ ) after standing for 30 minutes, which will be described later, was performed only for Examples 10 to 15 and Comparative Examples 4 to 5.
〔Evaluation method〕
1. 1. Concrete temperature The material temperature was adjusted so that the kneading temperature of concrete was 20 ± 3 ° C.
2. 2. Air volume The air volume immediately after kneading (A ₀ ) and the air volume after standing for 30 minutes (A ₃₀ ) were defined as follows, and the ratio was defined as the air volume retention ratio (A ₃₀ / A ₀ ).
・ Amount of air immediately after kneading (A ₀ )
The amount of air obtained by a test conducted according to JIS A 1128 using concrete immediately after kneading.
・ Amount of air after standing for 30 minutes (A ₃₀ )
The amount of air obtained by a test conducted in accordance with JIS A 1128 after kneading the concrete that had been allowed to stand for 30 minutes after kneading.
3. 3. Slump test The test was conducted according to JIS A 1101.
In the case of formulation 1, the fluidity was evaluated by the slump test.
4. Slump flow test A test was conducted according to JIS A 1150.
In the case of formulation 2, the fluidity was evaluated by a slump flow test.
5. Freezing and thawing test A test was conducted according to method A in JIS A 1148-2010, and the relative dynamic elastic modulus was measured up to a maximum of 300 cycles. A relative dynamic elastic modulus of 60% or more at 300 cycles was judged to be excellent in frost damage resistance.
6. Bubble spacing coefficient The bubble spacing coefficient, which is an index of freeze-thaw resistance, was measured with an air void analyzer (AVA; trade name, manufactured by German Instruments). Glycerin (manufactured by Wako Pure Chemical Industries, Ltd.) and water were mixed in advance at a mass ratio of glycerin / water = 83/17 to prepare a solution for AVA measurement.
The kneaded concrete was passed through a sieve having an opening of 5 mm to obtain a mortar for evaluating the bubble spacing coefficient, and 20 ml was collected in a special syringe. Approximately 2000 ml of water was injected into the measurement column, bubbles adhering to the wall surface of the column were removed with a brush, and then 250 ml of the AVA measurement solution prepared in advance was injected into the bottom of the column using a special instrument. After the injection, a Petri dish for collecting air bubbles was installed near the water surface of the column and fixed to the measurement part. After injecting 20 ml of the mortar collected in the syringe into the bottom of the column, the mortar was stirred for 30 seconds to sufficiently release the entrained air of the mortar into the liquid. The bubble spacing coefficient was measured by measuring the released bubbles over time.
In calculating the bubble spacing coefficient, the value (mortar volume ratio) excluding the volume occupied by the aggregate of 5 mm or more from the total concrete volume and the volume occupied by the paste (paste volume ratio) are required in addition to the amount of air in the fresh concrete. The mortar floor area ratio and the paste floor area ratio were calculated from the following formulas (I) and (II).
Mortar volume ratio _{(%) = [(V B} + V W + V S) / 1000] × 100 (I)
Paste floor area ratio (%) = [(V _B + V _W ) / 1000] x 100 (II)
V _B : Cement volume (= cement unit amount (kg) / specific gravity of cement)
V _W : Volume of liquid additives such as water, AE agent and water reducing agent (same as unit water amount)
V _S: (unit amount / density of fine aggregate = fine aggregate) 5 mm or less of the volume of the aggregate
7. Compressive strength A compressive strength test was conducted on concrete with a material age of 28 days according to JIS A 1108. The size of the specimen was φ10 × 20 cm.
8. Bleeding rate The test was conducted according to JIS A 1123.

As shown in Tables 4 and 6, it can be seen that by using the AE agent of the present invention, concrete having a small bubble spacing coefficient is obtained even when the antifoaming agent is used in combination.
Further, since the relative elastic modulus was 60% or more and the bleeding rate was 1.5% or less in each case, it was confirmed that the concrete was excellent in frost damage resistance and bleeding reduction effect.
Further, as shown in Table 6, a water-soluble substance having a ratio (A / B) of the mole fraction (A) of the methoxy group-substituted hydroxyalkyl group to the mole fraction (B) of the predetermined non-methoxy group-substituted hydroxyalkyl group. It was confirmed that good retention of air volume was exhibited by using the sex cellulose ether.
On the other hand, as shown in Table 5, when the AE agents as in Comparative Examples 1, 2, 4 and 5 are used, the bubble spacing coefficient becomes large, resulting in extremely poor frost damage resistance. You can see that.
Further, in the case of Comparative Example 3, since the water-soluble cellulose ether was not used, it can be seen that the bleeding rate was as high as 5.2%.

Claims (3)

Contains at least AE, water-soluble cellulose ether, defoamer, cement, water and aggregate,
The AE agent is a fatty acid represented by the following general formula (1), an alkali metal salt of a fatty acid represented by the following general formula (1), a lower alkylamine salt of a fatty acid represented by the following general formula (1), and the like. Alternatively, a fatty acid-based surfactant composed of a lower alkanolamine salt of a fatty acid represented by the following general formula (1) and a nonionic surfactant composed of a polyoxyethylene phenyl ether represented by the following general formula (2) are used. It includes,
The water-soluble cellulose ether is hydroxypropylmethyl cellulose or hydroxyethyl methyl cellulose.
The ratio (A / B) of the mole fraction (A) of the methoxy group-substituted hydroxypropyl group to the mole fraction (B) of the non-methoxy group-substituted hydroxypropyl group in the hydroxypropylmethyl cellulose is 0.2 to 1.0. Yes,
The ratio (A / B) of the mole fraction (A) of the methoxy group-substituted hydroxyethyl group to the mole fraction (B) of the non-methoxy group-substituted hydroxyethyl group in the hydroxyethyl methyl cellulose is 2.0 to 3.0. hydraulic composition, characterized in that there.

(In the formula, R ¹ represents an alkyl group or an alkenyl group having 12 to 24 carbon atoms.)

(In the formula, R ² represents an alkyl group having 8 or 9 carbon atoms, and n represents an integer of 1 to 50.) The AE agent, hydraulic composition according to claim 1, wherein the contained 0.0001% by weight relative to the cement. The hydraulic composition according to claim 1 or 2 , wherein the bubble spacing coefficient is 25 to 250 μm.