JP2010229016A - Concrete composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly versatile concrete composition which is low in price, suppresses strength reduction of hardened matter, suppresses cracking of a concrete hardened body by expressing an excellent shrink reduction function by suppressing water evaporation from the concrete hardened body caused by drying, imparts an excellent water reducing function because of good compatibility with a water reducing agent, further imparts excellent antifreeze dissolubility because the quality of entrained air can be easily improved by a defoaming agent and an AE agent, and can improve durability of the concrete hardened body. <P>SOLUTION: The concrete composition includes: a shrink reduction agent for concrete including a compound (A) represented by R<SP>1</SP>-[O-(A<SP>1</SP>O)<SB>m</SB>-R<SP>2</SP>]<SB>n</SB>where R<SP>1</SP>is an R<SP>1</SP>derived from a polyalcohol represented by R<SP>1</SP>-[OH]<SB>n</SB>, A<SP>1</SP>O is 2-18C oxyalkylene, R<SP>2</SP>is a hydrogen atom, or a 1-30C hydro carbon group, m is the average addition mole number of the oxyalkylene A<SP>1</SP>O, n is an integer of not less than 3, m is 30-150 when n=3, m is 5-450 when n=4, m is 10-500 when n≥5; and at least one water reducing agent (B) selected from the group consisting of sulfonic acid water reducing agents having a sulfonic acid group in the molecule, oxycarboxylic acids or salts thereof, sugars, and sugar alcohols; and cement. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a concrete composition. More specifically, the present invention relates to a concrete composition having an excellent shrinkage reducing function.

  The concrete composition gives a hardened concrete having excellent strength and durability. A concrete composition is indispensable for constructing civil engineering and building structures.

  After hardening, the concrete composition causes the unreacted moisture remaining inside to dissipate due to the outside air temperature and humidity conditions. For this reason, there is a problem that drying shrinkage proceeds, cracks occur in the cured product, and strength and durability are lowered. When the strength and durability of civil engineering and building structures are reduced, serious problems such as reduced safety and increased repair costs arise.

Laws and regulations have been strengthened against such problems. Under the law concerning the promotion of quality assurance of houses established in June 1999, cracks in concrete are also subject to warranty. According to the building construction standard specification (JASS 5 (Architectural Institute of Japan)) regarding reinforced concrete structure, which was revised in February 2009, the shrinkage strain at 26 weeks in concrete over a long life (100 years or more) is 800 × 10. ^It was regulated to ^-6 or less.

  Recently, a shrinkage reducing agent for concrete is regarded as important as a method for reducing drying shrinkage of a hardened concrete. Simultaneously with the revision of JASS 5, the establishment of the Architectural Institute standards for shrinkage reducing agents is scheduled.

  As shrinkage reducing agents for concrete, alkylene oxide adducts of alcohols having 1 to 4 carbon atoms (see Patent Document 1), co-adducts of ethylene oxide and propylene oxide of 2 to 8 polyhydric alcohols (see Patent Document 2) ), Alkylene oxide adduct of lower alkylamine (see Patent Document 3), polypropylene glycol in oligomer region (see Patent Document 4), low molecular weight alcohols (see Patent Document 5), alkylene oxide adduct of 2-ethylhexanol (see Patent Document 5) Patent Document 6) has been reported. These shrinkage reducing agents suppress drying shrinkage by reducing capillary tension generated by the formation of meniscus in pores inside the hardened concrete body due to evaporation of water by drying. However, these shrinkage reducing agents for concrete have a structure that is similar to AE agents and antifoaming agents used for the purpose of adjusting the amount of air and the problem that strength decreases when used in concrete. By interacting with these agents, there is a problem that the quality of the air entrained in the concrete is deteriorated and the freeze-thaw resistance is lowered. For this reason, it is necessary to increase the proportion of the cement paste in order to maintain the strength, and the use of these shrinkage reducing agents is limited in cold districts due to the problem of high concrete cost and reduced freeze-thaw resistance. Problem arises.

Japanese Patent Publication No. 56-51148 Japanese Patent Publication No. 1-53214 Japanese Patent Publication No. 1-53215 JP 59-152253 A Japanese Patent Publication No. 6-6500 Japanese Patent No. 2825855

  The purpose of the present invention is to reduce the strength of the cured product at low cost, and to exhibit excellent shrinkage reduction function by suppressing the evaporation of water from the cured concrete product by drying, thereby generating cracks in the cured concrete product. Suppresses and provides excellent water-reducing function due to good compatibility with water-reducing agent, and also provides excellent freeze-thaw resistance due to easy improvement of entrained air quality by antifoaming agent and AE agent It is another object of the present invention to provide a highly versatile concrete composition that can improve the durability of a hardened concrete.

The concrete composition of the present invention comprises:
A compound (A) represented by the general formula (1);
R ¹ — [O— (A ¹ O) _m —R ² ] _n (1)
(In General Formula (1), R ¹ represents R ¹ derived from a polyhydric alcohol represented by R ^1- [OH] _n , A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms, and R 1 ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, m represents an average added mole number of the oxyalkylene group A ¹ O, n is an integer of 3 or more, and when n = 3, m is 30 to 150, m is 5 to 450 when n = 4, and m is 10 to 500 when n is 5 or more.)
At least one water reducing agent (B) selected from a sulfonic acid-based water reducing agent having a sulfonic acid group in the molecule, oxycarboxylic acid or a salt thereof, sugar, and sugar alcohol;
Containing shrinkage reducing agent for concrete,
And cement.

  In a preferred embodiment, the shrinkage reducing agent for concrete of the present invention includes an AE agent (C) and an antifoaming agent (D).

  In a preferred embodiment, the ratio of the AE agent (C) and the antifoaming agent (D) is (C) / (D) = 90/10 to 10/90 in terms of a weight ratio in terms of solid content.

  In a preferred embodiment, the ratio of the compound (A), the water reducing agent (B), the AE agent (C), and the antifoaming agent (D) is [(A) + (C ) + (D)] / (B) = 99.9 / 0.1-40 / 60.

  In a preferred embodiment, the compound (A) is at least one selected from a trimethylolalkane alkylene oxide adduct, a pentatriol alkylene oxide adduct, and an alkylene oxide adduct of a polyhydric alcohol having 4 or more valences.

In a preferred embodiment, the A ¹ O contains an oxyalkylene group having 2 and 3 carbon atoms.

  According to the present invention, cracking of a hardened concrete body is achieved by exhibiting an excellent shrinkage reduction function by suppressing the strength reduction of the hardened material and suppressing the evaporation of water from the hardened concrete body by drying. Suppresses and provides excellent water-reducing function due to good compatibility with water-reducing agent, and also provides excellent freeze-thaw resistance due to easy improvement of entrained air quality by antifoaming agent and AE agent In addition, it is possible to provide a highly versatile concrete composition that can improve the durability of the hardened concrete.

≪Concrete shrinkage reducing agent≫
The shrinkage reducing agent for concrete in the present invention contains the compound (A) represented by the general formula (1).
R ¹ — [O— (A ¹ O) _m —R ² ] _n (1)

In the general formula (1), R ¹ represents R ¹ derived from a polyhydric alcohol represented by R ^1- [OH] _n .

In general formula (1), n is an integer of 3 or more. That is, when n = 3, the polyhydric alcohol represented by R ^1- [OH] _n is a trivalent polyhydric alcohol (trihydric alcohol: R ^1- [OH] ₃ ), and when n = 4 , R ^1- [OH] _n is a tetravalent polyhydric alcohol (tetrahydric alcohol: R ^1- [OH] ₄ ), and when n is 5 or more, R ^1- [OH The polyhydric alcohol represented by _n is a polyhydric alcohol having 5 or more valences.

  Specific examples of the trihydric alcohol include trimethylol alkanes such as trimethylolethane and trimethylolpropane, and 1,3,5-pentatriol. Trimethylol alkane is preferable, and trimethylolpropane is more preferable.

  Specific examples of the tetrahydric alcohol include erythritol and pentaerythritol. The tetrahydric alcohol is preferably pentaerythritol.

  Specific examples of the pentahydric or higher polyhydric alcohol include dipentaerythritol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, mannitol, and polyglycerin. Moreover, as sugars, saccharides of hexoses such as glucose, fructose, mannose, indose, sorbose, growth, talose, tagatose, galactose, allose, psicose, altrose; pentoses such as arabinose, ribulose, ribose, xylose, xylulose, lyxose Saccharides of Tetroses such as threose, erythrulose and erythrose; and other saccharides such as rhamnose, cellobiose, maltose and itoose. Dipentaerythritol, sorbitol, sorbitan, and polyglycerol are preferable.

In the general formula (1), A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms. A ¹ O is preferably an oxyalkylene group having 2 to 4 carbon atoms. Specific examples include an oxyethylene group, an oxypropylene group, and an oxybutylene group. When A 1 ^O number of carbon atoms is too large, solubility in water of concrete for a shrinkage reducing agent in the present invention may be lowered.

In general formula (1), A ¹ O may consist of only one oxyalkylene group or may consist of two or more oxyalkylene groups. When A ¹ O is composed of two or more oxyalkylene groups, they may be random adducts, block adducts, or alternating adducts. Also good.

In the general formula (1), ^{A 1} is preferably O 50 mol% or more is an oxyalkylene group having a carbon number of 2 and 3, ^{A 1} O 60 to 100 mol% oxy carbon atoms 2 and 3 More preferably, it is an alkylene group, more preferably 80 to 100 mol% of A ¹ O is an oxyalkylene group having 2 and 3 carbon atoms, and 90 to 100 mol% of A ¹ O is 2 carbon atoms. And oxyalkylene groups of 3 and 3. As a more preferred embodiment, in the general formula (1), preferably more than 50 mol% of the ^{A 1} O is an oxyalkylene group having 2 carbon atoms (oxyethylene groups), ^{A 1} O 60 to 100 mol% Is more preferably an oxyalkylene group having 2 carbon atoms (oxyethylene group), and more preferably 80-100 mol% of A ¹ O is an oxyalkylene group having 2 carbon atoms (oxyethylene group). It is particularly preferable that 90 to 100 mol% of A ¹ O is an oxyalkylene group having 2 carbon atoms (oxyethylene group).

In the general formula (1), m represents an average addition mole number of oxyalkylene groups A ^{1 O.}

  When n = 3, m = 30 to 150, preferably m = 30 to 120, and more preferably m = 30 to 90. By controlling m within the above range, the concrete shrinkage-reducing agent in the present invention can suppress a decrease in strength of the cured product and can exhibit an excellent shrinkage-reducing function.

  When n = 4, m = 5 to 450, preferably m = 5 to 200, more preferably m = 5 to 100, and further preferably m = 10 to 50. By controlling m within the above range, the concrete shrinkage-reducing agent in the present invention can suppress a decrease in strength of the cured product and can exhibit an excellent shrinkage-reducing function.

  When n is 5 or more, m = 10 to 500, preferably m = 10 to 250, and more preferably 10 to 100. By controlling m within the above range, the concrete shrinkage-reducing agent in the present invention can suppress a decrease in strength of the cured product and can exhibit an excellent shrinkage-reducing function.

In general formula (1), R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. R ² is more preferably a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms, further preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and particularly preferably a hydrogen atom or a carbon atom. It is a hydrocarbon group of number 1-6.

The molecular weight of the shrinkage reducing agent for concrete in the present invention is preferably a weight average molecular weight (Mw) in terms of polyethylene glycol by gel permeation chromatography (hereinafter referred to as “GPC”), preferably 500 to 500,000, more preferably 1000 to 300000, More preferably, it is 1000-200000, Most preferably, it is 1500-100000. If the weight average molecular weight (Mw) is less than 500, the water reducing performance of the hydraulic material additive of the present invention may be lowered. If the weight average molecular weight (Mw) exceeds 500,000, the water reducing performance and slump loss preventing ability of the concrete shrinkage reducing agent in the present invention may be lowered. In the present specification, the weight average molecular weight is a value measured under the following GPC measurement conditions.
[GPC molecular weight measurement conditions]
Column used: TSK guard column SWXL + TSKge1 G4000SWXL + G3000SWXL + G2000SWXL manufactured by Tosoh Corporation
Eluent: 115.6 g of sodium acetate trihydrate is dissolved in a mixed solvent of 10999 g of water and 6001 g of acetonitrile, and an eluent solution adjusted to pH 6.0 with a 30% aqueous sodium hydroxide solution is used.
Implanted amount: 100 μL of 0.5% eluent solution
Eluent flow rate: 0.8 mL / min
Column temperature: 40 ° C
Standard substance: polyethylene glycol, weight average molecular weight (Mw) 272500, 219300, 85000, 46000, 24000, 12600, 4250, 7100, 1470.
Calibration curve order: Tertiary detector: 410 manufactured by Waters, Japan 410 Differential refraction detector analysis software: MILRENNIUM Ver. Manufactured by Waters, Japan 3.21

  Specific examples of the compound (A) represented by the general formula (1) include, for example, a trimethylolalkane alkylene oxide adduct, a pentatriol alkylene oxide adduct, and an alkylene oxide adduct of a tetrahydric or higher polyhydric alcohol. At least one selected from is preferred. This is because the effects of the present invention can be sufficiently exhibited.

  The concrete shrinkage reducing agent in the present invention contains a water reducing agent (B). The water reducing agent (B) is at least one selected from a sulfonic acid-based water reducing agent having a sulfonic acid group in the molecule, oxycarboxylic acid or a salt thereof, a sugar, and a sugar alcohol.

  Any appropriate sulfonic acid-based water reducing agent can be used as the sulfonic acid-based water reducing agent, and a compound having an aromatic ring in the molecule is particularly preferable. Examples of the sulfonic acid water reducing agent include polyalkylaryl sulfonate water reducing agents such as naphthalene sulfonic acid formaldehyde condensate, methyl naphthalene sulfonic acid formaldehyde condensate and anthracene sulfonic acid formaldehyde condensate; melamine sulfonic acid formaldehyde condensate Melamine formalin resin sulfonate water reducing agent such as aminoaryl sulfonic acid-phenol-formaldehyde condensate aromatic amino sulfonate water reducing agent; lignin sulfonate salt such as lignin sulfonate and modified lignin sulfonate salt System water reducing agent; polystyrene sulfonate water reducing agent.

  Examples of the salt in the sulfonate include alkali metal salts, alkaline earth metal salts, ammonium salts, and organic ammonium salts.

  Examples of the oxycarboxylic acid or a salt thereof include gluconic acid, glucoheptonic acid, alabonic acid, malic acid, citric acid, alkali metal salts, alkaline earth metal salts, ammonium salts, and organic ammonium salts thereof.

  Examples of the sugar include monosaccharides such as glucose, galactose, saccharose, xylose, abiose, ribose and isomerized sugar; oligosaccharides such as disaccharide and trisaccharide; oligosaccharides such as dextrin; polysaccharides such as dextran; Can be mentioned.

  In the present invention, the water reducing agent (B) is preferably at least one selected from a sulfonic acid-based water reducing agent having a sulfonic acid group in the molecule, and oxycarboxylic acid or a salt thereof. In the present invention, the water reducing agent (B) is more preferably a polyalkylaryl sulfonate water reducing agent, a lignin sulfonate water reducing agent, and gluconic acid or a salt thereof (alkali metal salt, alkaline earth metal salt). , Ammonium salt, organic ammonium salt, etc.). In the present invention, the water reducing agent (B) is more preferably a lignin sulfonate water reducing agent and gluconic acid or a salt thereof (alkali metal salt, alkaline earth metal salt, ammonium salt, organic ammonium salt, etc.). At least one selected.

  The concrete shrinkage reducing agent in the present invention may be used in combination with an AE agent (C) or an antifoaming agent (D). Only 1 type may be used for AE agent (C) and an antifoamer (D), respectively, and 2 or more types may be used together.

  The ratio of the AE agent (C) and the antifoaming agent (D) is preferably (C) / (D) = 90/10 to 10/90 by weight ratio in terms of solid content, and (C) / ( D) = 80/20 to 20/80 is more preferable, and (C) / (D) = 70/30 to 30/70 is more preferable. If (C) / (D) is out of the above range, the effects of the present invention may not be sufficiently exhibited.

  The ratio of the compound (A), the water reducing agent (B), the AE agent (C), and the antifoaming agent (D) is [(A) + (C) + (D)] in weight ratio in terms of solid content. /(B)=99.9/0.1-40/60 is preferable, and [(A) + (C) + (D)] / (B) = 99.5 / 0.5-50 / 50 is more preferable. [[A) + (C) + (D)] / (B) = 99.5 / 0.5 to 70/30 is more preferable. If [(A) + (C) + (D)] / (B) is out of the above range, the effects of the present invention may not be sufficiently exhibited.

  Arbitrary appropriate AE agents can be employ | adopted as said AE agent (C). For example, resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, ABS (alkyl benzene sulfonic acid), LAS (linear alkyl benzene sulfonic acid), alkane sulfonate, polyoxyethylene alkyl (phenyl) ether, polyoxyethylene Examples include alkyl (phenyl) ether sulfate or a salt thereof, polyoxyethylene alkyl (phenyl) ether phosphate or a salt thereof, protein material, alkenylsulfosuccinic acid, and α-olefin sulfonate.

Any appropriate antifoaming agent can be adopted as the antifoaming agent (D). For example,
(1) Mineral oil-based antifoaming agents such as straw oil and liquid paraffin:
(2) Fat and oil-based antifoaming agents such as animal and vegetable oils, sesame oil, castor oil, and these alkylene oxide adducts:
(3) Fatty acid-based antifoaming agents such as oleic acid, stearic acid, and adducts thereof with alkylene oxide:
(4) Fatty acid ester antifoaming agents such as glycerin monoricinoleate, alkenyl succinic acid derivative, sorbitol monolaurate, sorbitol trioleate, natural wax, etc .:
(5) Polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adducts; diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, polyoxyethylene polyoxypropylene 2-ethylhexyl ether, carbon atom (Poly) oxyalkyl ethers such as oxyethyleneoxypropylene adducts to higher alcohols of 12 to 14; (poly) oxyalkylene (alkyl) aryl ethers such as polyoxypropylene phenyl ether and polyoxyethylene nonylphenyl ether 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl-3-hexyne-2,5-diol, 3-methyl-1-butyn-3-ol, etc. Ase Acetylene ethers obtained by addition polymerization of alkylene oxide to len alcohol; (poly) oxyalkylene fatty acid esters such as diethylene glycol oleate, diethylene glycol laurate, ethylene glycol distearate; polyoxyethylene sorbitan monolaurate, polyoxy (Poly) oxyalkylene sorbitan fatty acid esters such as ethylene sorbitan trioleate; (poly) oxyalkylene alkyl (aryl) ether sulfate such as sodium polyoxypropylene methyl ether sulfate and sodium polyoxyethylene dodecylphenol ether sulfate; (Poly) oxyalkylene alkyl phosphorus such as (poly) oxyethylene stearyl phosphate Esters; polyoxyethylene (poly) oxyalkylene alkyl amines such as polyoxyethylene lauryl amine; polyoxyalkylene amides; and the like oxyalkylene-based antifoaming agent:
(6) Alcohol-based antifoaming agents such as octyl alcohol, 2-ethylhexyl alcohol, hexadecyl alcohol, acetylene alcohol and glycols:
(7) Amide antifoaming agent such as acrylate polyamine:
(8) Phosphate ester antifoaming agents such as tributyl phosphate and sodium octyl phosphate:
(9) Metal soap antifoaming agents such as aluminum stearate and calcium oleate:
(10) Silicone antifoaming agents such as dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane) and fluorosilicone oil:
Is mentioned.

  As long as the shrinkage reducing agent for concrete in the present invention exhibits the effects of the present invention, other components may be used in combination as necessary. Other components include, for example, water-soluble polymer substances, polymer emulsions, retarders, early strengthening agents, accelerators, surfactants, waterproofing agents, rust preventives, crack reducing agents, expanding materials, cement wetting agents, Thickeners, separation reducers, flocculants, other drying shrinkage reducers, strength enhancers, self-leveling agents, rust inhibitors, colorants, fungicides, blast furnace slag, fly ash, cinder ash, clinker ash, husk Examples include ash, silica fume, silica powder, and gypsum. These may use only 1 type and may use 2 or more types together.

Arbitrary appropriate methods can be employ | adopted about the manufacturing method of the shrinkage reducing agent for concrete in this invention. For example, a method in which an alkylene oxide having 2 to 18 carbon atoms is added to the polyhydric alcohol represented by R ^1- [OH] _n described above in the presence of an alkali component (for example, sodium hydroxide) is mentioned. It is done.

  The concrete shrinkage reducing agent in the present invention has excellent water solubility and compatibility with a water reducing agent together with an excellent shrinkage reducing function. Since the shrinkage reducing agent for concrete in the present invention can be dissolved with water and a water reducing agent at an arbitrary ratio, the water / cement ratio is wide, and the water / cement ratio (weight ratio) is preferable. Can produce up to 60% to 15% concrete. Therefore, it is highly versatile and can be used by being added to a cement composition for various uses.

≪Concrete composition≫
The concrete composition of the present invention contains the above-mentioned concrete shrinkage reducing agent and cement. In the concrete composition of the present invention, the concrete shrinkage reducing agent is preferably added to a cement composition such as mortar made of cement, fine aggregate and water, and concrete made of coarse aggregate at a predetermined ratio. Is.

  Examples of the cement used in the production of the cement composition include normal, low heat, medium heat, early strength, ultra early strength, sulfate resistant portland cement, blast furnace cement, silica cement, fly ash cement, eco cement, silica fume, etc. Cement is mentioned. Examples of the powder in the cement composition include silica fume, fly ash, limestone fine powder, blast furnace slag fine powder, expansion material, and other mineral fine powders. Examples of the fine aggregate include river sand, mountain sand, sea sand, crushed sand, heavy aggregate, lightweight aggregate, slag aggregate, and recycled aggregate. Examples of the coarse aggregate include river gravel, crushed stone, heavy aggregate, lightweight aggregate, slag aggregate, and recycled aggregate. Examples of the water include tap water, water other than tap water (river water, lake water, well water, etc.) shown in Appendix 9 of JIS A 5308, and recovered water.

  Any appropriate additive may be added to the concrete composition of the present invention. For example, a hardening accelerator, a setting retarder, a rust preventive, a waterproofing agent, and an antiseptic can be used.

  Arbitrary appropriate methods can be employ | adopted about the manufacturing method of the concrete composition of this invention, a conveyance method, a placement method, a curing method, a management method, etc.

  In the concrete composition of the present invention, any appropriate amount can be adopted as the addition amount of the concrete shrinkage reducing agent in the present invention depending on the purpose. For example, it is preferable to set it as 0.5-10.0 weight% with respect to 100 weight part of cement. Moreover, when the cement capacity per 100 volume parts of cement compositions exceeds 14 volume%, Preferably it is 0.5-10.0 weight% with respect to 100 weight part of cement, More preferably, it is 0.5-6.0. It is preferable to set it as weight%.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples. Unless otherwise specified, parts and% in the examples are based on weight.

[Measurement of solid content of each component used in concrete blending]
The solid content of each component used for evaluating the physical properties of the concrete was measured as follows.
1. An aluminum dish was precisely weighed.
2. A component for measuring the solid content was placed on a precisely weighed aluminum dish and weighed precisely.
3. The components precisely weighed in 2 above were placed in a dryer adjusted to 130 ° C. in a nitrogen atmosphere for 1 hour.
After 4.1 hours, the above components were removed from the dryer and allowed to cool in a desiccator for 15 minutes.
After 5.15 minutes, the dried components were removed from the desiccator, and the aluminum dish and the dried components were precisely weighed.
6). The solid content was calculated by the following formula.
Solid content (%) = {[(weight obtained with the above-described 5 precision balance)-(weight obtained with the above-described precision balance of 1)] / [(weight obtained with the above-described precision balance of 2)-( Weight obtained with the precision balance of 1)]} × 100

[Stability test]
In a 100 ml glass transparent screw tube, the compound (A) and water reducing agent (B) referred to in the present invention are placed so that the compound (A): water reducing agent (B) = 9: 1 (solid content ratio). After shaking well, the mixture was allowed to stand overnight at room temperature and 50 ° C., and the appearance was observed.
The results of appearance observation were evaluated as follows.
○: Transparent and uniform dissolution △: Cloudy but uniform dissolution ×: Separation into two layers

[Concrete property evaluation]
≪Evaluation of slump value and air volume≫
About the taken-out concrete (fresh concrete), the slump value and the air quantity were evaluated by the following methods.
Slump value: JIS A 1101-1998
Air volume: JIS A 1128-1998

≪Evaluation of drying shrinkage reduction≫
The taken-out concrete (fresh concrete) is put into a specimen formwork (10 × 10 × 40 cm) with a gauge pin, sealed and cured at 20 ° C. for 1 day, demolded, and still for 20 days at 20 ° C. in still water. After water curing, the drying shrinkage reduction property was evaluated.
The evaluation of the drying shrinkage reduction was carried out according to JIS A1129-3 (Testing method for changing the length of mortar and concrete, Part 3: Dial gauge method).
The surface of the specimen cured in still water for 6 days was wiped off with a paper towel and then immediately measured, and the length at this point was used as a reference. Thereafter, the sample was stored in a constant temperature and humidity chamber set at a temperature of 20 ° C. and a humidity of 60%, and the amount of shrinkage strain was measured.

≪Measurement of bubble spacing coefficient≫
After kneading concrete with a predetermined amount of air using AE agent and antifoaming agent, mortar from which aggregates of 6 mm or more have been removed is freeze-resistant with an air void analyzer (AVA; trade name, German Instruments) The bubble spacing coefficient, which is an index of melting property, was measured.
First, 250 ml of an AVA measurement solution adjusted to 20 ° C. and about 2000 ml of water were measured. Next, after filling the measuring column, 20 ml of mortar was collected and injected into the bottom of the column. After the injection, the mortar was stirred for 30 seconds to sufficiently release the entrained air of the mortar into the liquid. The bubble spacing coefficient was calculated by measuring the released bubbles over time. When calculating the bubble spacing coefficient, the value (mortar volume ratio) excluding the volume occupied by aggregates of 6 mm or more from the total concrete volume was set to 64.3%.

≪Evaluation of freeze-thaw resistance≫
The obtained fresh concrete was put into a 10 × 10 × 40 cm specimen mold, demolded after sealing at 20 ° C. for 2 days, and further cured in water at 20 ° C. in still water for 28 days, and then freeze-thaw resistant. Evaluation was conducted.
The freeze-thaw resistance was evaluated by measuring the primary resonance frequency and the specimen weight according to JIS A 1127-2001 every 30 cycles according to method A in JIS A 1148-2001.
At this time, the freeze-thaw resistance for each 30 cycles is determined from the primary resonance frequency at the end of each cycle relative to the primary resonance frequency before the start of the freeze-thaw cycle (0 cycle), as shown by the following formula (1). The relative dynamic elastic modulus was calculated and evaluated. The maximum number of freeze-thaw cycles was 300, and the evaluation was terminated when the relative kinematic modulus became 60% or less before 300 cycles. The final freeze-thaw resistance was evaluated by calculating a durability index represented by the following formula (2). These values indicate that the closer to 100, the better the freeze-thaw resistance.
Relative kinematic modulus (%) = (f _n ² / f ₀ ² ) × 100 (1)
f _n : primary resonance vibration (Hz) after n cycles of freezing and thawing
f ₀ : primary resonance vibration (Hz) after 0 cycles of freezing and thawing
Durability index = (P × N) / 300 (2)
P: Relative kinematic modulus (%) during freeze-thaw N cycles
N: The number of freeze-thaw cycles where the relative kinematic modulus is 60% or less, or 300 cycles, whichever is smaller

[Production Example 1]
In a pressure vessel equipped with a stirrer, a pressure gauge, and a thermometer, 190 g of commercially available trimethylolpropane and 4.12 g of sodium hydroxide were charged. Next, after raising the temperature of the reaction system to 120 ° C. or higher, 1871.4 g of ethylene oxide was added while maintaining the temperature at 150 ± 5 ° C., and an intermediate in which 10 mol each of ethylene oxide was added to the active hydrogen of trimethylolpropane ( 1) was obtained.
In a pressure vessel equipped with a stirrer, a pressure gauge, and a thermometer, 340 g of the intermediate (1) was charged. Subsequently, the temperature of the reaction system was raised to 150 ° C. Next, while maintaining the temperature at 150 ± 5 ° C., 2006.3 g of ethylene oxide was added to obtain a compound (1) in which 75 mol of ethylene oxide was added to each active hydrogen of trimethylolpropane.

[Production Example 2]
In a pressure vessel equipped with a stirrer, a pressure gauge, and a thermometer, 500 g of commercially available pentaerythritol and 1.15 g of sodium hydroxide were charged. Next, after raising the temperature of the reaction system to 120 ° C. or higher, 647.1 g of ethylene oxide was added while maintaining the temperature at 150 ± 5 ° C., and an intermediate in which 1 mol of ethylene oxide was added to each active hydrogen of pentaerythritol (2 -1) was obtained.
In a pressure vessel equipped with a stirrer, a pressure gauge, and a thermometer, 350 g of intermediate (2) and 1.67 g of sodium hydroxide were charged. Next, after the temperature of the reaction system was raised to 150 ° C., 1743.2 g of ethylene oxide was added while maintaining the temperature at 150 ± 5 ° C., and an intermediate in which 10 mol each of ethylene oxide was added to the active hydrogen of pentaerythritol (2- 2) was obtained.
In a pressure vessel equipped with a stirrer, a pressure gauge, and a thermometer, 400 g of the intermediate (2-2) and 0.15 g of sodium hydroxide were charged. Next, the temperature of the reaction system was raised to 120 ° C. or higher. Next, 370.1 g of ethylene oxide was added while maintaining the temperature at 150 ± 5 ° C. to obtain a compound (2) in which 20 mol of ethylene oxide was added to each active hydrogen of pentaerythritol.

[Reference Examples 1-4]
Using the compound (A) and water reducing agent (B) shown in Table 1, they were blended as shown in Table 2 and subjected to a stability test. The results are shown in Table 2.

[Comparative Reference Examples 1-4]
Using the compound (A) and water reducing agent (B) shown in Table 1, they were blended as shown in Table 2 and subjected to a stability test. The results are shown in Table 2.

  As shown in Table 2, the compound (1) and compound (2), which are ethylene oxide adducts of a trivalent or tetravalent alcohol as the component A, are good without any separation when mixed with any water reducing agent. Showed good solubility. On the other hand, in each of the compounds (3) and (4) having only one oxyalkylene chain containing propylene oxide in the molecule, separation from the water reducing agent was observed in both cases, and a decrease in solubility was observed. It was.

[Examples 1-5, Comparative Examples 1-3]
≪Concrete mix≫
Each material was weighed so that the mixing amount was 30 L according to the concrete mixing ratio shown below, and the material was kneaded using a forced biaxial kneading mixer. As the cement, ordinary portland cement (specific gravity 3.16) manufactured by Taiheiyo Cement Co., Ltd., Sumitomo Osaka Cement Co., Ltd., and Ube Mitsubishi Cement Co., Ltd. was used. At this time, Kakegawa land sand and Kimitsu land sand were used as fine aggregates, and Ome hard sandstone was used as coarse aggregates. Also, using an air amount adjusting agent (AE agent (C) and antifoaming agent (D): see Table 1), the concrete flow value was adjusted to 8 ± 1 cm and the air amount was adjusted to 5 ± 1%. .
<Concrete mix ratio>
Unit cement amount: 301 kg / m ³
Unit water volume: 160 kg / m ³
Unit fine aggregate amount: 824 kg / m ³
Unit coarse aggregate amount: 1002 kg / m ³
(Water-cement ratio (W / C): 53%, fine aggregate ratio (s / a): 46.0%)
≪Mixing ingredients≫
Coarse aggregate and half of the fine aggregate to be used are put into the mixer and kneaded for 5 seconds. Then, rotation is stopped and cement and the remaining fine aggregate are put in. After further kneading for 5 seconds, rotation is stopped again. Then, water containing a compound (A), a water reducing agent (B), an AE agent (C), and an antifoaming agent (D) was added and kneaded for 90 seconds, and then the concrete was taken out from the mixer.
≪Evaluation≫
Using the compound (A), water reducing agent (B), AE agent (C), and antifoaming agent (D) shown in Table 1, the concrete was evaluated as shown in Table 3. The results are shown in Table 4.

  The smaller the value of the bubble spacing coefficient, the finer and more densely dispersed the bubbles entrained in the concrete (good quality bubbles are entrained in the concrete), and the better the freeze-thaw resistance. Indicates. In the case of Examples 1 to 4 in which the compound (A) referred to in the present invention was blended, the bubble spacing coefficient was smaller than that in Comparative Examples 1 to 3 without blending, and therefore the compound (A) according to the present invention. It can be seen that the quality of the air entrained in the concrete is improved by blending. Moreover, the shrinkage | contraction distortion in dry material age 1 and 4 weeks is also reduced.

  According to the concrete composition of the present invention, it is inexpensive, suppresses a decrease in strength of the cured product, suppresses occurrence of cracks in the cured concrete body by an excellent shrinkage reduction function, and has good compatibility with a water reducing agent. An excellent water-reducing function can be imparted, and furthermore, the quality of entrained air can be easily improved by the antifoaming agent and the AE agent, so that excellent freeze-thaw resistance can be imparted, and the durability of the hardened concrete can be improved.

  According to the present invention, it is inexpensive, suppresses a decrease in strength of the cured product, suppresses the occurrence of cracks in the hardened concrete by an excellent shrinkage reduction function, and has an excellent water reducing function because of its good compatibility with a water reducing agent. Furthermore, since the quality of the entrained air can be easily improved by the antifoaming agent and the AE agent, it is possible to impart excellent freeze-thaw resistance and improve the durability of the hardened concrete, and is highly versatile. A concrete composition can be provided.

Claims (6)

A compound (A) represented by the general formula (1);
R ¹ — [O— (A ¹ O) _m —R ² ] _n (1)
(In General Formula (1), R ¹ represents R ¹ derived from a polyhydric alcohol represented by R ^1- [OH] _n , A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms, and R 1 ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, m represents an average added mole number of the oxyalkylene group A ¹ O, n is an integer of 3 or more, and when n = 3, m is 30 to 150, m is 5 to 450 when n = 4, and m is 10 to 500 when n is 5 or more.)
At least one water reducing agent (B) selected from a sulfonic acid-based water reducing agent having a sulfonic acid group in the molecule, oxycarboxylic acid or a salt thereof, sugar, and sugar alcohol;
Containing shrinkage reducing agent for concrete,
And including cement,
Concrete composition.   The concrete composition according to claim 1, wherein the concrete shrinkage reducing agent includes an AE agent (C) and an antifoaming agent (D).   The concrete according to claim 2, wherein the ratio of the AE agent (C) and the antifoaming agent (D) is (C) / (D) = 90/10 to 10/90 in terms of weight ratio in terms of solid content. Composition.   The ratio of the compound (A), the water reducing agent (B), the AE agent (C), and the antifoaming agent (D) is [(A) + (C) + (D)] in a weight ratio in terms of solid content. The concrete composition according to claim 2, wherein /(B)=99.9/0.1 to 40/60.   The compound (A) is at least one selected from a trimethylolalkane alkylene oxide adduct, a pentatriol alkylene oxide adduct, and an alkylene oxide adduct of a polyhydric alcohol having 4 or more valences. A concrete composition according to any one of the above. The concrete composition according to any one of claims 1 to 5, wherein the A ¹ O contains oxyalkylene groups having 2 and 3 carbon atoms.