JP6363354B2 - Concrete admixture - Google Patents

Description

  The present invention relates to a concrete admixture and a concrete admixture kit, and more specifically, a shrinkage reducing agent for cement composition having excellent self-shrinkage reducing properties and dry shrinkage reducing properties, and a specific polycarboxylic acid excellent in water-reducing properties. The present invention relates to a concrete admixture that can be provided as a single cement and a concrete admixture kit in which these can be added separately.

  Up to now, alkylene oxide adducts of lower or higher alcohols have been used as concrete shrinkage reducing agents for more than 20 years (for example, Patent Document 1). These compounds are generally used for the purpose of reducing drying shrinkage that occurs several days to several years after concrete or mortar is cured.

In recent years, in ultra-high-strength concrete exceeding the design strength of 100 N / mm ² , from the viewpoint of suppressing cracking of the hardened body, self-shrinkage that occurs at the early stage of hardening of the concrete, that is, the progress of cement hydration reaction, concrete, mortar and paste Attention has been focused on how to reduce shrinkage due to volume reduction.
In the alkylene oxide adducts of the lower alcohols proposed so far, proposals have been made to reduce self-shrinkage at the very young age immediately after placement by optimizing the structure of the compound (for example, Patent Documents). 2).

On the other hand, from the viewpoint of simplifying the production of concrete, it is desired that the shrinkage reducing agent can be used as a single component with a water reducing agent (cement dispersant) in practical use.
For example, Patent Document 3 proposes an alkylene oxide adduct of alkylamine as a shrinkage reducing agent for a hydraulic material in consideration of a drying shrinkage reducing effect and compatibility with a water reducing agent. Patent Document 4 proposes a one-component additive for a hydraulic composition containing a water reducing agent and a drying shrinkage reducing agent. Furthermore, a cement composition containing a cement dispersant and a shrinkage reducing agent has been proposed (Patent Document 5).
Heretofore, a polycarboxylic acid-based cement dispersant has been proposed as a cement dispersant with improved dispersibility (water reduction) in a low water binder ratio region (Patent Document 6).

JP 2010-37116 A JP 2010-229014 A JP 2010-58996 A JP 2013-60365 A JP 2012-184129 A Japanese Patent No. 3740641

As described above, in ultra-high-strength concrete with a design standard strength exceeding 100 N / mm ² , the occurrence of internal stress and cracks, which are mainly caused by self-shrinkage due to hardening, is a major problem, and the conventional drying shrinkage reduction effect In addition, there is an urgent need to further improve the self-shrinkage reduction effect.
In particular, in consideration of the self-shrinkage reducing effect described above, the shrinkage reducing agent is preferably added at the same time as the cement dispersant and the water reducing agent are added. In that case, the compatibility with the cement dispersant added simultaneously is excellent. In addition, there is a need for a proposal that enables the cement dispersant and shrinkage reducing agent to be made into one component.

  The present invention has been made in view of the above-described problems, and can provide a combination of a cement dispersant and a shrinkage reducing agent excellent in compatibility with each other and capable of realizing one-component liquefaction that is technically difficult. Furthermore, it is an object of the present invention to provide a combination of a cement dispersant and a shrinkage reducing agent that can improve the effects of both shrinkage reduction and water reduction, preferably synergistically, by the combined use of both additives. Is.

As a result of the study by the present inventors, in the alkylene oxide adduct of lower alcohol as a shrinkage reducing agent, the terminal of the alkylene oxide addition part is alkylated, that is, the compound in which both ends of the alkylene oxide addition part are alkylated is shrunk. By adopting as a reducing agent, the shrinkage reducing effect is further enhanced compared to conventionally proposed shrinkage reducing agents, and further by using a higher amine alkylene oxide adduct together here, a polycarboxylic acid dispersant at normal temperature It has been found that excellent compatibility with can be realized. Also, among the dispersants to be combined, by using a specific polycarboxylic acid-based dispersant having a polyamide polyamine chain, the compatibility of both additives is higher than when combined with other polycarboxylic acid-based dispersants. It has been found that not only the improvement and the one-componentization can be realized, but also the shrinkage reduction effect of the combined shrinkage reducing agent can be further enhanced.
Furthermore, in addition to these components, by combining an alkylene oxide adduct of a lower alcohol, the separation between the shrinkage reducing agent and the polycarboxylic acid dispersant at high temperature (for example, 40 ° C.) is improved, and the compatibility of both additives And the present invention was completed by finding that the one-component property can be further enhanced.

（式中、Ｒ_１及びＲ_２はそれぞれ独立して炭素原子数１乃至４のアルキル基を表し、但し、ｎはオキシエチレン（ＥＯ）基の平均付加モル数であって２又は３を表す。）

（式中、Ｒ_３は炭素原子数９乃至２４の炭化水素基を表し、ｍ_１及びｍ_２はそれぞれオキシエチレン（ＥＯ）基の平均付加モル数であって０乃至３０を表し、但しｍ_１とｍ_２の合計値は１乃至３０を表し、ｍ _１ とｍ _２ は同一である。） That is, the present invention comprises a polycarboxylic acid cement dispersant composed of a polymer compound having a polyamide polyamine chain, a compound A represented by the following formula [1] and a compound B represented by the following formula [2], It is related with the concrete admixture characterized by including the shrinkage | contraction reducing agent for cement compositions included by the mass ratio of compound A: compound B = 99: 1-50: 50.

(In the formula, R ₁ and R ₂ each independently represents an alkyl group having 1 to 4 carbon atoms , where n is the average number of added moles of an oxyethylene (EO) group and represents 2 or 3). )

(Wherein, _{R 3} represents a hydrocarbon group represents, m ₁ and _{m 2} be in 0 to 30 the average number of moles of addition of, respectively it oxyethylene (EO) group having a carbon number of 9 to 24, provided that the sum of m ₁ and _{m 2} is 1 to 30 and Table, _{m 1} and _{m 2} are the same.)

  The present invention also provides a polycarboxylic acid cement dispersant comprising a polymer compound having a polyamide polyamine chain, a compound A represented by the formula [1] and a compound B represented by the following formula [2]. Further, the present invention also relates to a concrete admixture kit characterized by comprising a combination with a shrinkage reducing agent for cement composition containing at a mass ratio of Compound A: Compound B = 99: 1 to 50:50.

  The shrinkage reducing agent used in the concrete admixture and the concrete admixture kit of the present invention is further lower in addition to the compound A represented by the formula [1] and the compound B represented by the formula [2]. An alkylene oxide adduct of alcohol may be included, and at this time, preferably, the compound A, the compound B, and the alkylene oxide adduct of the lower alcohol are included in a mass ratio of 98: 1: 1 to 25:25:50. It is desirable.

INDUSTRIAL APPLICABILITY The present invention can provide a concrete admixture that is excellent in compatibility between a cement dispersant and a shrinkage reducing agent, does not separate even after long-term storage after being liquefied, and has excellent one-liquid stability. Further, the concrete admixture kit of the present invention is excellent in compatibility between the cement dispersant and the shrinkage reducing agent, so that both additives can be used without causing separation at the time of introduction on site.
In particular, according to the present invention, by combining a specific polycarboxylic acid-based dispersant and a specific shrinkage reducing agent, the shrinkage reduction effect can be further improved compared to the case where these additives are added individually. Can do. In particular, the cement shrinkage reducing agent employed in the present invention can reduce both the shrinkage phenomenon caused not only by dry shrinkage but also by self-shrinkage due to the hydration reaction of the cement, and exhibits an excellent shrinkage reducing effect and admixture. Kits can be provided.
Furthermore, by adding an alkylene oxide adduct of a lower alcohol to the shrinkage reducing agent used in the present invention, not only at a low temperature (for example, 0 to 2 ° C.) and at a normal temperature (for example, 20 ° C.), but also at a high temperature (for example, 40 The concrete admixture excellent in the one-component stability with the cement dispersant used together or the concrete admixture kit excellent in the compatibility of both additives can be provided.

《Concrete admixture and concrete admixture kit》
The present invention is directed to a one-component concrete admixture containing a polycarboxylic acid cement dispersant composed of a polymer compound having a polyamide polyamine chain and a specific shrinkage reducing agent for cement composition described later.
The present invention is also directed to a concrete admixture kit comprising a combination of the polycarboxylic acid-based cement dispersant and the shrinkage reducing agent for cement composition, that is, these can be added individually.
Hereinafter, the shrinkage reducing agent for cement composition and the polycarboxylic acid cement dispersant constituting the present invention will be described in detail.

<Shrinkage reducing agent for cement composition>
The shrinkage reducing agent for cement composition used in the present invention is a compound obtained by modifying an alkylene oxide adduct of a lower alcohol (compound A), a higher amine such as an alkylene oxide adduct of a higher alkylamine or a higher alkenylamine (compound B). And may further contain an alkylene oxide adduct (Compound C) of a lower alcohol.

[Compound A]
Compound A constituting the shrinkage reducing agent for cement composition used in the present invention is a compound represented by the following formula [1]. In the present invention, instead of the conventionally used alkylene oxide adducts of lower alcohols (compounds with one end alkylated), by adopting a compound with both ends alkylated, a compound with one end alkylated is obtained. Compared with the case of using, the self-shrinkage reduction effect can be enhanced.

In the formula [1], R ₁ and R ₂ each independently represents an alkyl group having 1 to 4 carbon atoms.
Examples of the alkyl group include linear, branched or cyclic alkyl groups. Accordingly, preferred groups for R ₁ and R ₂ are methyl, ethyl, n-propyl, i-propyl, cyclopropyl, n-butyl, i-butyl, sec-butyl, tert- A butyl group, a cyclobutyl group, etc. are mentioned.
The total number of carbon atoms of the alkyl groups R ₁ and R ₂ in Compound A is preferably 2 to 6 from the viewpoint of improving the kneadability, and from the viewpoint of improving the one-component property, the total number of carbon atoms is 3 to 6 is preferred. Further, from the viewpoint of improving self-shrinkage reduction, it is preferably 3 to 8, and more preferably 4 to 8.
Among them, it is preferable that _one of R ₁ and R ₂ represents an n-butyl group and the other represents a methyl group.

In the formula [1], EO represents an oxyethylene group, and n is the average number of added moles of the oxyethylene (EO) group and represents 2 or 3.
Among these, by setting n to 3, the state is further improved from the viewpoints of improving self-shrinkage reduction and kneading.

[Compound B]
Compound B constituting the shrinkage reducing agent for cement composition used in the present invention is a compound represented by the following formula [2]. By using the following compound B (an alkylene oxide adduct of a higher alkylamine or a higher alkenylamine) together with the compound A, compatibility of the shrinkage reducing agent with a cement dispersant described later, and other additives at room temperature. Can be improved and one-pack can be realized.

In the formula [2], R ₃ represents a hydrocarbon group having 9 to 24 carbon atoms, the number of carbon atoms is 10 to 20 from the viewpoint of improving the one-component property, and the number of carbon atoms is 12 to 12 from the viewpoint of improving the fluidity. 20 is preferable, and a hydrocarbon group having 12 to 18 carbon atoms is particularly preferable.
Examples of the hydrocarbon group having 9 to 24 carbon atoms include an alkyl group having 9 to 24 carbon atoms or an alkenyl group having 9 to 24 carbon atoms, which are linear, branched or cyclic. Either may be sufficient.
Preferred groups for R ₃ are decyl, dodecyl (lauryl), tetradecyl (myristyl), hexadecyl (palmityl), octadecyl (stearyl), eicosyl, myristolyl, palmitoleyl, An oleyl group, a linoleyl group, a linoleyl group, a ricinoleyl group and the like can be mentioned, and a lauryl group and an oleyl group are particularly preferable, and a lauryl group is most preferable.

Wherein [2], EO represents an oxyethylene group, _{m 1} and _{m 2} represent an in 0 to 30 the average number of moles of addition of, respectively it oxyethylene (EO) group, provided that the _{m 1} and _{m 2} the total value from 1 to 30 and Table, _{m 1} and _{m 2} are the same.
Among these, from the viewpoint of reducing the self-shrinkage and improving the one-component property, the total value of m ₁ and m ₂ is preferably 2 to 20, and more preferably 2 to 10.

In the shrinkage reducing agent for cement composition used in the present invention, the compound A represented by the above formula [1] and the compound B represented by the formula [2] are A: B = 99: 1 to 50:50. Included by mass ratio. By setting the compounding ratio of these compounds in the above range, the shrinkage reducing agent not only can obtain high self-shrinkage reducing properties, but also has excellent compatibility with the cement dispersant described later, and is used for cement compositions. The one-component property of the shrinkage reducing agent and the cement dispersant can be excellent.
Preferably, by setting the numerical range of the mass ratio of the above compound A: compound B to 99: 1 to 60:40, it is possible to reduce the influence of delay or inhibition of the hydration reaction, and further 99: 1 to By setting it as 80:20, fluidity | liquidity can be improved, the influence on a hydration reaction can be decreased further, and early strength development can be obtained. For example, as for these compounding ratios (mass ratio), 87.5: 12.5-80: 20 is mentioned.

[Compound C: alkylene oxide adduct of lower alcohol]
Further, the shrinkage reducing agent for cement composition used in the present invention, in addition to the compound A represented by the above formula [1] and the compound B represented by the formula [2], as long as the effects of the present invention are not impaired, Furthermore, an alkylene oxide adduct of a lower alcohol can be blended. An example of such a compound is compound C represented by the following formula [3].
In the present invention, by properly using Compound C, the separation between the shrinkage reducing agent at a high temperature (for example, 40 ° C.) and the cement dispersant described later can be improved, and the compatibility and further the one-part property of both can be enhanced. .

In the formula [3], R ₄ represents an alkyl group having 1 to 8 carbon atoms, and is preferably an alkyl group having 1 to 4 carbon atoms from the viewpoint of compatibility with the compound A.
The alkyl group may be linear, branched or cyclic.
Preferred groups for R ₄ are methyl, ethyl, n-propyl, i-propyl, cyclopropyl, n-butyl, i-butyl, sec-butyl, tert-butyl, cyclobutyl. Among them, preferred are methyl group and n-butyl group.

In the formula [3], AO represents an oxyalkylene group having 2 to 4 carbon atoms. An oxyethylene group or an oxypropylene group is preferable, and an oxyethylene group is particularly preferable.
Further, q is an average addition mole number of the oxyalkylene group AO and represents 2 to 10, preferably 2 to 8, and more preferably 3 to 4.
The oxyalkylene groups to be added may be the same oxyalkylene group or two or more different oxyalkylene groups, and when different oxyalkylene groups are added, either random addition or block addition may be used. There may be.

  When blending the alkylene oxide adduct (compound C) of the lower alcohol, compound A: compound B: compound C is preferably blended in a mass ratio of 98: 1: 1 to 25:25:50. In particular, by setting the numerical range of the mass ratio of A: B: C to 78: 1: 20 to 30:20:50, the shrinkage reducing agent and the cement dispersant described later can be used at a high temperature (for example, 40 ° C.). The compatibility and the one-component stability are more likely to be ensured (it is difficult to separate), which is preferable. For example, 70: 10: 20-40: 10: 50 is mentioned as these compounding ratios (mass ratio).

<Cement dispersant>
The cement dispersant used in the present invention is not particularly limited as long as it is a polycarboxylic acid cement dispersant made of a polymer compound having a polyamide polyamine chain. For example, (meth) acrylate having a (poly) oxyalkylene chain, etc. Polyalkylene glycol monomers such as (meth) acrylic acid monomers such as (meth) acrylic acid and / or salts thereof, and polyamide polyamine monomers such as (meth) acrylates having a polyamide polyamine chain A polycarboxylic acid-based copolymer (Patent No. 323502, Patent No. 3346456, Patent No. 3780456 and Patent No. 6740641, incorporated herein by reference) can be suitably employed. (In this specification, (meta) acrelain Meaning both acrylate and methacrylate and).
Examples of commercially available products include SEICAMENT 1100NT and SEICAMENT 1200N, which are polycarboxylic acid-based high-performance AE water reducing agents manufactured by Nippon Seika Co., Ltd.

（式中、Ｒ_５は水素原子またはメチル基を、Ｒ_６はそれぞれ同一かまたは異なって炭素原子数２乃至４のアルキレン基を表し、ｐは自然数を表し、Ｒ_７は水素原子または炭素原子数１乃至４の炭化水素基を表す。） The (meth) acrylate having the (poly) oxyalkylene chain (hereinafter also referred to as compound D) is specifically a compound represented by the following formula [4].

(Wherein R ₅ represents a hydrogen atom or a methyl group, R ₆ is the same or different and represents an alkylene group having 2 to 4 carbon atoms, p represents a natural number, and R ₇ represents a hydrogen atom or the number of carbon atoms. 1 to 4 hydrocarbon groups are represented.)

The (meth) acrylate having a (poly) oxyalkylene chain (when R ₅ is a hydrogen atom, it is an acrylate, and when R ₅ is a methyl group, it is a methacrylate), the (meth) acryloyl group has (poly) oxy It is a monomer for introducing an (poly) oxyalkylene chain into the side chain of the polymer compound after polymerization, in which alkylene chains are linked. R ₆ is any one of an ethylene group, a propylene group, and a butylene group, and the (R ₆ O) p group may be composed of only one type of group, or a plurality of types of (R ₆ O) are randomly selected. An addition or a block may be added. R ₇ is a hydrogen atom, a methyl group, an ethyl group, a propyl group or a butyl group.

Specific examples of the (meth) acrylate having the (poly) oxyalkylene chain include polyethylene glycol mono (meth) acrylate and methoxypolyethylene glycol mono (meth) acrylate. These include (meth) method for adding an alkylene oxide having the above R ₆ acrylic acid or methanol and the like by adding an alkylene oxide having the above R _6, the alkyl portion of the alkylene oxide monoalkyl ether (alkyl ethers above, after obtaining the alkyl group R _7), which (meth) can be synthesized by methods such as for acrylic acid and esterification.
Moreover, the average added mole number of alkylene oxide corresponds to n. The p is preferably 1 to 200, but the more preferable lower limit of the added mole number n for further exhibiting the effect of the (poly) oxyalkylene chain is 2 mol. A more preferable upper limit of the added mole number n is 150 mol, and a more preferable upper limit is 100 mol. The addition reaction of alkylene oxides may be carried out at about 20 to 250 ° C. under pressure, with addition of a catalyst if necessary.

The (meth) acrylic acid and / or salt thereof (hereinafter also referred to as compound E) introduces a carboxyl group and / or carboxylate group into the side chain of the resulting polymer compound (polycarboxylic acid copolymer). It is a monomer for As the salt, sodium salt, potassium salt, ammonium salt, mono-, di- or triethanolamine salt and the like are preferable, and among them, sodium salt and ammonium salt are preferable in terms of performance and economy. The neutralization rate is not particularly limited and may be any of 0 to 100%, but when used as an additive, it is adjusted to about neutral (pH 7) (acid and salt coexisting state), and safety when handling From this point, it is preferable. The neutralization may be performed before, during or after the polymerization of the polycarboxylic acid copolymer.

  The (meth) acrylate (hereinafter also referred to as compound F) having a polyamide polyamine chain is a monomer for introducing a polyamide polyamine chain into the side chain of the resulting polymer compound. This (meth) acrylate having a polyamide polyamine chain is, for example, an ester (f-2) of a polyalkylene polyamine (f-1) and a dibasic acid and / or a dibasic acid and a lower alcohol having 1 to 4 carbon atoms. ) And (meth) acrylic acid and / or (meth) acrylic acid and an ester (f-3) of a lower alcohol having 1 to 4 carbon atoms can be synthesized.

  The polyalkylene polyamine (f-1) is preferably a compound having 3 or more amino groups, such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, tripropylenetetramine, tetrapropylenepenta. Min etc. are mentioned, These can be used individually or in mixture of 2 or more types.

  Among the dibasic acids and / or esters (f-2) of dibasic acids and lower alcohols having 1 to 4 carbon atoms, malonic acid, succinic acid, fumaric acid, maleic acid, glutar Examples thereof include acids, adipic acid, pimelic acid, azelaic acid, sebacic acid and the like, and these can be used alone or in admixture of two or more. These react with the amino group of the polyalkylene polyamine (f-1) to form a polyamide polyamine chain moiety. In addition, mono- and diesters of these dibasic acids also perform an amide group-forming reaction by a carboxyl group part, and also an amide group-forming reaction by an ammonolysis reaction in the ester part, so part or all of (f-2) Can be used as Since the reaction with the polyalkylene polyamine (f-1) proceeds smoothly when the ester formation partner does not have a bulky group, the lower alcohol having 1 to 4 carbon atoms, that is, methyl alcohol, ethyl Alcohol, propanol and butanol are preferably used.

  The (meth) acrylic acid and / or its reactive derivative (f-3) is composed of the polyalkylene polyamine (f-1), a dibasic acid and / or a dibasic acid, and a lower alcohol having 1 to 4 carbon atoms. It is a compound for imparting radical polymerizability to the polyamide polyamine chain portion produced by the reaction with the ester (f-2). If (f-3) is (meth) acrylic acid, the carboxyl group and the amino group in the polyamide polyamine react to produce (meth) acrylate having a polyamide polyamine chain in the side chain. . The reactive derivative of (meth) acrylic acid means a (meth) acrylic acid derivative having reactivity with an amino group, and an ester of (meth) acrylic acid and a lower alcohol having 1 to 4 carbon atoms. Moreover, glycidyl (meth) acrylate etc. are mentioned as a representative example. Since (meth) acrylic acid ester reacts with an amino group by an ammonolysis reaction, and the glycidyl group of glycidyl (meth) acrylate also reacts with an amino group, these reactive derivatives are also part or all of the component (f-3). Can be used as As the ester-forming partner, lower alcohols having 1 to 4 carbon atoms, that is, methyl alcohol, ethyl alcohol, propanol, and butanol are preferable as in the case of (f-2) above.

In the reactions (f-1) to (f-3), a dibasic acid and / or a dibasic acid and a lower alcohol having 1 to 4 carbon atoms are added to 1 mol of the polyalkylenepolyamine (f-1). It is preferable to react 0.5 to 0.95 mol of the ester (f-2) and 0.05 to 1.0 mol of (meth) acrylic acid and / or its reactive derivative (f-3). If the amount of the component (f-2) is too small, the polyamide polyamine chain will not be lengthened only by increasing the amount of unreacted materials. If the amount is too large, the molecular weight of the product will be too large and handling may be difficult. If the amount of the component (f-3) is too small, a large amount of non-polymerizable reaction product may be formed. If the amount is too large, a polyfunctional monomer is formed, and the amphoteric polymer compound is formed. There is a risk of gelation during polymerization.

  The above reactions (f-1) to (f-3) can be carried out by batch charging, or (f-1) and (f-2) are reacted first, and then (f-3) is reacted. Any method may be used, and it may be carried out in the presence of a known polymerization inhibitor.

  When synthesizing the (meth) acrylate having the polyamide polyamine chain, in addition to (f-1) to (f-3), an alkylene oxide may be subjected to an addition reaction. Since alkylene oxide is added to the amino group portion, (meth) acrylate having a polyamide polyamine chain further has a (poly) oxyalkylene chain, and the resulting amphoteric polymer compound has an effect of reducing concrete viscosity and phase. Increase solubility. However, if the number of added moles of alkylene oxide is excessive, hydroxy groups that increase the affinity with water and amino groups that are cations will decrease, resulting in a decrease in concrete viscosity reducing effect and compatibility. . Accordingly, the number of moles of alkylene oxide added is 16 moles or less with respect to 1 mole of imino group of (meth) acrylate having a polyamide polyamine chain before the addition reaction (theoretical value that can be calculated from the charged amount of each reaction raw material). More preferably 8 mol or less). The alkylene oxide to be added is preferably an alkylene oxide having an alkylene group having 2 to 4 carbon atoms such as ethylene oxide, propylene oxide, or butylene oxide.

In addition, as a polycarboxylic acid cement dispersant composed of a polymer compound having a polyamide polyamine chain, which is an essential component of the additive of the present invention, the (meth) acrylate having a (poly) oxyalkylene chain described above (compound) D), (meth) acrylic acid and / or a salt thereof (compound E), and a raw material monomer component (G) essentially containing (meth) acrylate (compound F) having a polyamide polyamine chain was polymerized. A copolymer can be used conveniently.
When the raw material monomer component (G) is composed only of the compound D, the compound E and the compound F, the (meth) acrylate (compound D) having a (poly) oxyalkylene chain is preferably 20 to 90% by mass, more preferably 50-90% by mass, (meth) acrylic acid and / or salt thereof (compound E) is preferably 2-40% by mass, more preferably 5-30% by mass, and (meth) acrylate having a polyamide polyamine chain (Compound F) is preferably polymerized at a ratio of 5 to 40% by mass, more preferably 5 to 20% by mass (provided that the total amount of Compound D, Compound E and Compound F is 100% by mass). Is preferred. This is because the above range is a range in which the effect as the cement dispersant described above can be exhibited in a well-balanced manner.

  The raw material monomer component (G) may contain other monomers other than the compound D, the compound E and the compound F, such as methyl (meth) acrylate, ethyl (meth) acrylate, n- Use (meth) acrylate such as propyl (meth) acrylate, vinyl acetate, styrene, α-methylstyrene, vinyltoluene, acrylonitrile, maleic anhydride, allyl alcohol alkylene oxide adduct, methallylsulfonic acid, styrenesulfonic acid, etc. However, in order to ensure the water solubility of the resulting polymer compound (polycarboxylic acid copolymer), these other monomers are added in 100% by mass of the raw material monomer component (G). It is desirable to suppress it to 10 mass% or less. When other monomers are used, the ratio of Compound D, Compound E, and Compound F should be adjusted so as to be in the above range when the total of Compound D, Compound E, and Compound F is 100% by mass. Good.

  The polymerization method of the raw material monomer component (G) is not particularly limited, and may be performed by a known polymerization method such as (water) solution polymerization, bulk polymerization, emulsion polymerization or the like using a known radical polymerization initiator. Since the resulting polymer compound is water-soluble, aqueous solution polymerization is preferable. Sulfate compounds such as sodium persulfate, potassium persulfate, ammonium persulfate, sodium persulfate, sodium hydrogensulfite, and 2,2′-azobis (2-amidino Polymerization may be performed as appropriate under known conditions using a water-soluble radical polymerization initiator such as a water-soluble azo compound such as propane) dihydrochloride and 4,4′-azobis (4-cyanopentanoic acid).

  The polymer compound preferably has a Mw (weight average molecular weight, in terms of polyethylene glycol) of 5,000 or more and 500,000 or less. More preferable Mw is 5,000 or more and 100,000 or less. If the molecular weight is too low, the degree of expression of the various effects described above will be insufficient, but if the molecular weight is too high, the cement dispersion effect will be significantly reduced, which is not preferable.

<Combination ratio>
In the concrete admixture or concrete admixture kit of the present invention, the blending ratio (mass ratio) of the above-mentioned polycarboxylic acid cement dispersant and the shrinkage reducing agent for cement composition is as follows: cement dispersant: shrinkage reducing agent = 1:99 to 99: 1, preferably 70:30 to 99: 1.
A concrete admixture composed of the cement dispersant and shrinkage reducing agent, or an admixture kit composed of a combination thereof is usually used in the range of 0.1 to 10% by mass with respect to cement. It is preferable to use in the range of mass%.

<Other additives>
The concrete admixture or concrete admixture kit of the present invention can be combined by appropriately adopting publicly known chemical admixtures and the like. Specifically, high-performance AE water reducing agent, high-performance water reducing agent, AE water reducing agent, water reducing agent, air entraining agent (AE agent), foaming agent, antifoaming agent, curing agent, water repellent, setting accelerator and At least one other concrete additive selected from the group consisting of setting retarders can be blended.
The concrete admixture and the concrete admixture kit to which the present invention is directed are a one-component concrete admixture comprising the above polycarboxylic acid cement dispersant and a shrinkage reducing agent, and further known concrete additives to the concrete admixture. A form in which the polycarboxylic acid cement dispersant and the shrinkage reducing agent are individually added at the time of concrete production, and the polycarboxylic acid cement dispersant and the shrinkage reducing agent containing the concrete additive at the time of concrete production. The form added individually, the form in which the polycarboxylic acid cement dispersant and the shrinkage reducing agent including the concrete additive are individually added during concrete production, and the polycarboxylic acid containing the concrete additive during concrete production A cementitious cement dispersant and the concrete additive No shrinkage reducing agent also include any form which is added to each.

  Examples of known water reducing agents (cement dispersants) include the above-mentioned polycarboxylic acids used in the present invention, such as JP-B-58-383380, JP-B-59-18338, JP-A-2628486, and JP-A-2744445. Examples include salts of other polycarboxylic acid copolymers other than the cementitious cement dispersant. Water reducing agents (cement dispersants) other than polycarboxylic acid-based copolymers include naphthalene sulfonic acid formalin condensate salts, melamine sulfonic acid formalin condensate salts, lignin sulfonate, sodium gluconate, sugar alcohol, etc. Is mentioned.

Specific examples of the air entraining agent (AE agent) include <1> anionic air entraining agent, <2> nonionic air entraining agent, and <3> amphoteric air entraining agent. <1> As anionic air entraining agents, sulfate salts of higher alcohols (or adducts thereof), alkylbenzene sulfonates, rosin soaps, maleated rosin soaps and other resin soap salts, higher alcohols (or alkylene oxides thereof) (2) nonionic air entraining agents such as alkylene glycol, higher alcohol alkylene oxide adduct, fatty acid and alkylene glycol ester, sugar alcohol alkylene glycol adduct, etc. <3> Examples of amphoteric air entraining agents composed of anions and cations include alkylbetaine type, alkylamide betaine type, and amino acid type amphoteric activator type.

  Examples of antifoaming agents include nonionic defoaming agents such as aliphatic alcohol alkylene oxide adducts, fatty acid alkylene oxide adducts, alkylene oxide difatty acid esters, polyhydric alcohol alkylene oxide adducts, polyalkylene polyamine alkylene oxide adducts, etc. And silicone-based antifoaming agents using silicone oil as an emulsion, higher alcohols using higher alcohol as an emulsion, and mixtures containing these as main components.

  Examples of the setting accelerator include inorganic accelerators represented by calcium chloride, calcium nitrite and the like, and organic accelerators represented by alkanolamine and the like.

  Examples of setting retarders include: <1> inorganic setting retarders: phosphates, silicofluorides, zinc oxide, zinc carbonate, zinc chloride, zinc monoxide, copper hydroxide, magnesia salts, borax, boron oxide <2> Organic coagulation retarders: phosphonic derivatives, saccharides and derivatives thereof, oxycarboxylates, lignin sulfonates, and more specific examples include phosphonic derivatives: aminotri (methylenephosphonic acid), aminotri (methylenephosphonic acid) ) Pentasodium salt, 1-hydroxyethylidene-1, 1-diphosphonic acid, diethylenetriaminepenta (methylenephosphonic acid) and alkali metal salts, phosphonic acids of alkaline earth metal salts and derivatives thereof, saccharides: saccharose, maltose, raffinose, lactose Glucose, fructose, mannose, arabinose, key Loin, Abitosu, Repose, oxycarboxylate: gluconic acid, citric acid, glucoheptonic acid, malic acid, tartaric acid, their alkali metal salts, alkaline earth metal salts.

The component constituting the cement composition to which the concrete admixture or the concrete admixture kit of the present invention is applied is a conventional concrete component, such as cement, for example, ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement. , Low heat / medium heat Portland cement or blast furnace cement, aggregates, ie fine aggregates and coarse aggregates, admixtures such as silica fume, calcium carbonate powder, blast furnace slag fine powder, fly ash, expansion material and water it can.
The concrete admixture or concrete admixture kit of the present invention is excellent not only in its one-component property or compatibility, but also in its compatibility with water, as well as excellent shrinkage reduction. That is, the application range of the water / cement ratio is wide, and it can be applied to concrete having various strengths of 60 to 15% in the water / cement ratio (mass%). In particular, it can be suitably applied to ultra-high strength concrete having a water / cement ratio of 20% or less, and can exhibit an excellent self-shrinkage reducing effect.

  The concrete admixture or concrete admixture kit of the present invention may be added after kneading concrete or mortar (immediately before placing) and kneaded uniformly again, but in order to obtain an excellent self-shrinkage reducing effect, It is preferable to use it by adding at the time of concrete kneading or by diluting and adding to kneading water in advance.

The clear reason for how the excellent shrinkage reduction effect of the concrete admixture or the concrete admixture kit of the present invention is obtained has not yet been elucidated. As one of the assumptions, in the hydration reaction process of the cement composition, as the internal temperature of the cement composition increases, the shrinkage reducing agent employed in the present invention effectively promotes the hydrophobization in the system. It is considered to have an excellent shrinkage reducing effect and strength development. Furthermore, the shrinkage reduction effect can be improved by combining a polycarboxylic acid cement dispersant made of a polymer having a polyamide polyamine chain.

  The following examples illustrate the invention. However, the present invention is not limited to these examples and comparative examples.

[Preparation of shrinkage reducing agent]
Shrinkage reducing agents X1 to X11 and comparative shrinkage reducing agents Y1 to Y4 were prepared using the compounds A to C shown in Table 1 and the mixing ratio (mass ratio) thereof.

Further, as the comparative shrinkage reducing agent Y5, the self-shrinkage reducing agent (a-1) (2-ethylhexanol 3 mol EO adduct) disclosed in JP 2010-229014 A was employed, and Production Example 1 (JP 2010-229014 A). Prepared according to the procedure described in the paragraph [0033].

  For the prepared shrinkage reducing agents X3 and X10 and comparative shrinkage reducing agents Y1, Y2 and Y5, the cloud point (° C.) and the particle size distribution were measured and evaluated according to the following procedure and evaluation. The obtained results are shown in Table 2.

<Method of measuring cloud point>
Each shrinkage reducing agent was diluted with water to prepare 5 and 16 mass% aqueous solutions, and the cloud point was measured.
<Measurement method of particle size distribution>
Each shrinkage reducing agent is diluted with water to prepare a 16% by mass aqueous solution, and the particle size distribution at the cloud point of each aqueous solution is measured using a laser diffraction particle size distribution analyzer SALD-2300 (manufactured by Shimadzu Corporation). did.

As shown in Table 2, the shrinkage reducing agents (X3 and X10) used in the concrete admixture of the present invention had a particle size distribution of less than 1 μm at the cloud point of 100%.
The influence that the particle size of the shrinkage reducing agent may have on shrinkage reduction and strength development has not yet been elucidated. However, in the shrinkage reducing agent for cement composition used in the present invention, by combining the compounds A and B in an optimal ratio, an aggregate having a function of adjusting the particle size by temperature stimulation in water is formed. It is thought that there is. The shrinkage-reducing agent having a controlled particle size is considered to remain at an optimum size in the microstructure of the cement composition, and it is thus presumed that the shrinkage accompanying the progress of the hydration reaction is reduced.

<Various evaluation tests as concrete admixture>
[Test 1: One-component stability confirmation test for concrete admixture]
As a polycarboxylic acid-based cement dispersant comprising 15 parts of a shrinkage reducing agent (see Table 3 below) prepared as described above and a polymer compound having a polyamide polyamine chain, Example 4 of JP-A No. 2004-210589 65 parts of a water-soluble amphoteric copolymer (solid content concentration 37%, hereinafter referred to as polycarboxylic acid-based cement dispersant PD) and 20 parts of water were mixed. After mixing, the mixture was stored at 20 ° C. and 40 ° C. for 3 months, and the appearance was compared visually. According to the following evaluation index, the one-component stability of the concrete admixture was evaluated. The obtained results are shown in Table 3.
<One-component stability evaluation index>
◎: The appearance of the concrete admixture is transparent and uniform ○: The appearance of the concrete admixture is stagnant but uniformly dispersed ×: The cement dispersant and shrinkage reducing agent are separated into two layers State

  As shown in Table 3, the concrete admixture of the present invention in which a cement dispersant and a shrinkage reducing agent were mixed was excellent in one-component stability at 2 ° C. storage, 20 ° C. storage and 40 ° C. storage. . In particular, in the shrinkage reducing agent X10 containing Compound C (lower alcohol alkylene oxide adduct), a transparent and uniform state was maintained even after storage at 40 ° C. for 3 months, and a result showing excellent one-component stability was obtained. .

[Test 2: Fresh mortar test]
As a cement dispersant, polycarboxylic acid-based cement dispersant PD (0.6 mass% added in terms of solid content with respect to cement mass) and each of the above shrinkage reducing agents (addition amount to cement: see Table 4) are added in advance. The prepared kneading water was added to the cement and fine aggregate, and kneaded at a low speed using a high power mixer (manufactured by Maruto Seisakusho Co., Ltd.) (Example 3 to Example 13, Comparative Example 5 to Comparative Example). 10) In Comparative Example 4, only the cement dispersant was added. The mixing at low speed was continued until the materials were integrated visually, and the integration time was recorded as the mixing time. Subsequently, it knead | mixed for 120 second at high speed, and produced the test mortar. Table 4 shows the unit amount of each material of the mortar subjected to the test.
For these mortars just after kneading, the spread of the mortar (miniflow) is measured using a mini slump cone (top inner diameter 50 mm, lower end inner diameter 100 mm, height 150 mm) according to JIS A 1171 “Test method for polymer cement mortar”. did. After the miniflow measurement, the state of the mortar was visually confirmed. Further, the amount of air immediately after kneading and after 60 minutes was measured. The total mass method was adopted for the measurement of the air amount, and the air amount was calculated by the following formula from the result of measurement using a graduated cylinder.
Air amount (%) = [1- (Mortar mass) / (Mortar mass at 0% of air amount determined from formulation)] × 100
In addition, an antifoaming agent (polyoxyalkylene alkyl ether fatty acid ester-based antifoaming agent) is appropriately used in combination with the mortar used in the test, and the amount of air in the mortar immediately after kneading is adjusted by adjusting the amount used. It adjusted so that it might become 0% or less. All of these agents, including concrete admixtures (cement dispersants, shrinkage reducing agents), were weighed as part of the water for testing.
The results obtained are shown in Table 5.

[Test 3. Curing property confirmation test: mortar]
Fill the mortar produced in the procedure of Test 2 into a plastic container with a diameter of 10 cm and a height of 12 cm, put it in the center of a simple insulated box made of urethane foam, and embedded concrete with Kyowa Denki Co., Ltd. Strain gauge: KMC-70-120-H4, Data logger: NTB
Using -100A-120 and NTB-201A, the internal temperature of the mortar and the shrinkage strain in the hydration reaction process were measured. The maximum temperature and the time to reach the maximum temperature (exothermic peak) were confirmed from the history of the internal temperature of the mortar. The results obtained are shown in Table 5.
This test measures the active state of the initial hydration reaction that affects the setting time and initial strength, and the maximum temperature reflects the heat of reaction accompanying the hydration reaction of the cement. In Comparative Example 4 in which the shrinkage reducing agent was not blended, the result that the maximum temperature and the exothermic peak deviated greatly compared to other examples in which the shrinkage reducing agent was blended (see the comparative example in particular) was It has a large influence on the initial hydration reaction.
Moreover, the mortar produced in the procedure of Test 2 was filled in a plastic mold having a diameter of 5 cm and a height of 10 cm, and demolded after 24 hours. The removed specimen was cured in water at 20 ° C., and the compressive strength at the age of 7 and 28 days was measured according to the procedure of JIS A 1108.
The results obtained are shown in Table 5.

As shown in Table 5, in the fresh mortar test and the curing property confirmation test (mortar) assuming ultra high strength concrete having a water / cement ratio of 15%, the concrete admixtures of the present invention (shrinkage reducing agents X1 to X11 and Examples 3 to 13 using the polycarboxylic acid-based cement dispersant PD) are comparative examples 5 to 13 using the concrete admixture of the comparative example (using the comparative shrinkage reducing agents Y1 to Y5 as shrinkage reducing agents). Compared with Example 10, the result that the surface of each material was united in the mortar state and was fresh was obtained.
In addition, Examples 3 to 13 have a faster exothermic peak and a higher maximum temperature than Comparative Examples 5 to 10, and a result comparable to that of Comparative Example 3 with no shrinkage reducing agent added. Therefore, it is presumed that the influence on the initial hydration reaction is small (the delay or inhibition of the hydration reaction is small). In addition, with respect to the compressive strength, a result that the strength comparable to that of Comparative Example 3 with no shrinkage reducing agent was obtained was obtained, and this result is also presumed to reflect the effect of not inhibiting the progress of the hydration reaction. .
Further, in Examples 3 to 13 using the concrete admixture of the present invention, the shrinkage strain in the hydration reaction process is reduced by about 23% to 33% as compared with Comparative Example 1 in which no shrinkage reducing agent was added. In comparison with Comparative Examples 4 to 10 using the concrete admixture of Comparative Example, the result was that the shrinkage was reduced by 10% or more. In Comparative Example 10, the use of the concrete admixture in which the shrinkage reducing agent was increased by a factor of 2 exhibited the same shrinkage reduction effect as in the examples, but the exothermic peak and the maximum temperature were observed. As a result, the influence on the initial hydration reaction was very large and the compression strength was poor.

[Test 4: Fresh concrete test]
Polycarboxylic acid-based cement dispersant PD as a cement dispersant, shrinkage reducing agent X10 prepared as described above, and comparative shrinkage reducing agent (Japanese Patent Laid-Open No. 2010-150085: shrinkage reducing agent 1 is adopted) The mixing water prepared by adding Table 6) in advance was added to the cement and fine aggregate, and the mixture was kneaded at 50 rpm for 7 minutes using a super double mixer (55 L, manufactured by Taiheiyo Kikai Co., Ltd.). Thereafter, the coarse aggregate was put into a mixer and kneaded at 50 rpm for 2 minutes. After standing for 5 minutes, the concrete was discharged and various measurements shown below were performed. Table 6 shows unit amounts of each material of the concrete subjected to the test.
About the concrete after kneading, according to the procedure of JIS A 1150, the slump flow, 50 cm flow arrival time, the amount of air immediately after kneading and after 30 minutes according to the procedure of JIS A 1128 were measured, and the state of the concrete was visually confirmed. .
In addition, 0.01 mass% of defoaming agents (polyoxyalkylene alkyl ether fatty acid ester-based defoaming agents) are used in combination with the concrete used in the test with respect to the cement. All of these agents, including concrete admixtures (cement dispersants, shrinkage reducing agents, antifoaming agents), were weighed as part of the water for testing.
The results obtained are shown in Table 7.

[Test 5. Curing property confirmation test: Concrete]
The fresh concrete produced by the procedure of Test 4 is filled into a mold 10 cm long x 10 cm wide x 40 cm high, and a strain gauge KM-100BT manufactured by Tokyo Sokki Kenkyujo Co., Ltd. is embedded in the center of the mold. It is. This was put in the center of a simple insulating box made of polystyrene foam, and the internal temperature of the concrete and the shrinkage strain in the hydration reaction process were measured using a data logger TDS-303 manufactured by Tokyo Sokki Kenkyujo Co., Ltd. The internal temperature of the concrete was 63.4 ° C. in Example 14 and 65.3 ° C. in Comparative Example 11.
In addition, according to the procedure of JIS A 1147, the coarse aggregate contained in the fresh concrete prepared in the procedure of Test 4 is removed by a wet screening method to obtain a mortar, and the initial and final times of setting of the mortar are measured. did.
Furthermore, the fresh concrete produced by the procedure of Test 4 was filled in a steel mold having a diameter of 10 cm and a height of 20 cm according to the procedure of JIS A 1132, and demolded after 24 hours. The removed specimen was cured in water at 20 ° C., and the compressive strength at the age of 7 days, 28 days and 56 days was measured according to the procedure of JIS A 1108.
The results obtained are shown in Table 7.

As shown in Table 7, in the fresh concrete test and the hardenability confirmation test (concrete) assuming ultra high strength concrete having a water / cement ratio of 14.4%, the concrete admixture (shrinkage reducing agent X10 and Example 14 using the polycarboxylic acid-based cement dispersant PD) is superior to the comparative example 11 using the concrete admixture of the comparative example, and has excellent slump flow dispersibility, and the surface of each material is integrated. The result was fresh.
Further, in Example 14, compared with Comparative Example 11, the setting time was short for both the start and end, the shrinkage strain in the hydration reaction process was reduced by about 20%, and the compression strength was also excellent. These results are presumed to reflect that the concrete admixture of the present invention (particularly the shrinkage reducing agent) has a very small influence on the initial hydration reaction (the delay or inhibition of the hydration reaction is small).

Claims (8)

A polycarboxylic acid-based cement dispersant composed of a polymer compound having a polyamide polyamine chain, a compound A represented by the following formula [1], and a compound B represented by the following formula [2], compound A: compound B = Concrete admixture characterized by including a shrinkage reducing agent for cement composition contained at a mass ratio of 99: 1 to 50:50.

(In the formula, R ₁ and R ₂ each independently represents an alkyl group having 1 to 4 carbon atoms , where n is the average number of added moles of an oxyethylene (EO) group and represents 2 or 3). )

(Wherein, _{R 3} represents a hydrocarbon group represents, m ₁ and _{m 2} be in 0 to 30 the average number of moles of addition of, respectively it oxyethylene (EO) group having a carbon number of 9 to 24, provided that the sum of m ₁ and _{m 2} is 1 to 30 and Table, _{m 1} and _{m 2} are the same.) The concrete admixture according to claim 1, wherein the shrinkage reducing agent for cement composition further contains an alkylene oxide adduct of a lower alcohol. The shrinkage reducing agent for cement composition comprises the compound A, the compound B, and an alkylene oxide adduct of the lower alcohol in a mass ratio of 98: 1: 1 to 25:25:50. The concrete admixture described. Further, selected from the group consisting of high performance AE water reducing agent, high performance water reducing agent, AE water reducing agent, water reducing agent, AE agent, foaming agent, defoaming agent, curing agent, water repellent, setting accelerator and setting retarder. The concrete admixture according to claim 1, further comprising at least one other concrete additive. A polycarboxylic acid-based cement dispersant composed of a polymer compound having a polyamide polyamine chain, a compound A represented by the following formula [1], and a compound B represented by the following formula [2], compound A: compound B A concrete admixture kit comprising a combination with a shrinkage reducing agent for a cement composition contained at a mass ratio of 99: 1 to 50:50.

(In the formula, R ₁ and R ₂ each independently represents an alkyl group having 1 to 4 carbon atoms , where n is the average number of added moles of an oxyethylene (EO) group and represents 2 or 3). )

(Wherein, _{R 3} represents a hydrocarbon group represents, m ₁ and _{m 2} be in 0 to 30 the average number of moles of addition of, respectively it oxyethylene (EO) group having a carbon number of 9 to 24, provided that the sum of m ₁ and _{m 2} is 1 to 30 and Table, _{m 1} and _{m 2} are the same.) The concrete admixture kit according to claim 5, wherein the shrinkage reducing agent for cement composition further contains an alkylene oxide adduct of a lower alcohol. The shrinkage reducing agent for a cement composition includes the compound A, the compound B, and an alkylene oxide adduct of the lower alcohol in a mass ratio of 98: 1: 1 to 25:25:50. The concrete admixture kit described. The polycarboxylic acid-based cement dispersant and / or the shrinkage reducing agent for cement composition further includes a high performance AE water reducing agent, a high performance water reducing agent, an AE water reducing agent, a water reducing agent, an AE agent, a foaming agent, and an antifoaming agent. And at least one other concrete additive selected from the group consisting of an agent, a curing agent, a water repellent, a setting accelerator, and a setting retarder. Concrete admixture kit.