JP2011102221A - Copolymer as cement dispersant, mixing agent for concrete including the same, and cement composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mixing agent for concrete and a cement composition in which a cement dispersant is mixed in order to improve workability of the cement composition of a low water/powder ratio and improve performances of hardened material of the cement composition. <P>SOLUTION: A copolymer comprises the following repeated units (A), (B) as the cement dispersant and has a weight average molecular weight of 5,000-100,000, wherein the molar ratio of (A) is 10-50%, (A) being at least two kinds represented by formula and the molar ratio of (B) is 30-90%, (B) being at least one kind represented by formula (B-1) or the like. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a copolymer as a cement dispersant for the purpose of improving the workability of a cement composition having a low water powder ratio and improving the performance of a cured product, and a cement composition containing the copolymer.

  Cement dispersants are known to adsorb on cement particles in cement compositions such as concrete and stabilize the dispersion of cement particles. Water-reducing agent, high-performance water-reducing agent, AE water-reducing agent or high-performance AE water-reducing agent It is used as the main raw material for concrete admixtures. (AE) Water-reducing agent and high-performance (AE) water-reducing agent are used for the purpose of reducing the unit water volume of concrete and can greatly contribute to improving the performance of concrete structures, especially durability. It has been recognized as one of these.

  Concrete structures in civil engineering / architecture are becoming larger and taller with the development of technology, and the performance required for concrete is becoming higher. Especially in the foundations and foundations of such large and high-rise structures, ultra-high-strength concrete is used, which has a higher strength and durability than ordinary concrete and has an extremely reduced ratio of water to cement and other powders. Often done. Super high-strength concrete needs to disperse many powders with a small amount of water to impart fluidity and reduce viscosity, so high-performance water reducing agents developed for ultra-high strength concrete are used. Yes.

Moreover, when manufacturing such ultra-high-strength concrete, it is common to use the ultrafine particle powder whose specific surface area measured with a Blaine specific surface area meter such as silica fume exceeds 10,000 cm ² / g. In addition, cement cements that are premixed with silica fume are also commercially available for ultra-high-strength concrete. Specifically, silica fume cement manufactured by Ube Mitsubishi Cement Co., Ltd., VKC100SF manufactured by Dai Shi Co., Ltd., Silica fume premix cement manufactured by Taiheiyo Cement Co., Ltd. is commercially available and generally used.

  Patent Document 1 describes a super-high-strength hydraulic cement composition to which a methacrylic acid-methacrylic acid polyalkylene oxide ester-polyalkylene glycol allyl ether copolymer is added. Patent Document 2 describes a cement dispersant for ultra-high performance concrete using a methacrylic acid-methacrylic acid polyalkylene glycol ester copolymer having a polyamide polyamine or an alkylene oxide adduct thereof. Patent Document 3 is obtained by polymerizing a copolymer of a specific alkenyl ether and maleic acid or a salt thereof, a specific monomer such as methacrylic acid ester of methoxypolyethylene glycol and a specific monomer such as methacrylic acid. It is described that a dispersant for a hydraulic composition containing a copolymer is particularly effective for a hydraulic composition in an ultrahigh strength region having a W / C of 30% or less. In Patent Document 4, a polycarboxylic acid copolymer obtained by copolymerizing a monomer component containing a polyalkylimine unsaturated monomer and an unsaturated carboxylic acid monomer is suitable for ultrahigh strength concrete. It is described that it is a polycarboxylic acid polymer that can be used.

Due to such technical innovation in concrete chemical admixtures, concrete having higher strength and durability as described above has been developed and put into practical use. Its development has become more sophisticated as the years progress. In recent years, ultra-high-strength concrete with a design standard strength of 150 N / mm ² has been applied to actual structures. Application of ultrahigh-strength concrete of mm ² to actual structures is being studied. That the level of concrete is improved in this way, that is, concrete with a lower water-powder ratio is produced, and in the prior art described in Patent Documents 1 to 4, imparting dispersibility, From the viewpoint of reducing the viscosity and securing an appropriate setting time, it is insufficient.

  Patent Document 5 discloses that a specific water-soluble vinyl copolymer sharing a relatively long polyethylene graft chain and a relatively short polyethylene graft chain in a molecule is used in high-strength concrete having a water cement ratio of 20 to 40%. Although described as being effective, such a technique using side chains of different lengths is a technique based on a methacrylic acid copolymer as a basic structure. Furthermore, it does not mention the effect in the ultra high strength concrete region where the water powder ratio is less than 20%.

  Patent Document 6 discloses a dispersant containing two types of copolymers containing a polyalkylene glycol (meth) acrylate monomer and a specific proportion of a specific unsaturated monomer as constituent units. Ultra high strength concrete, especially when the copolymer has a different average addition mole number of polyalkylene glycol and the product of the average addition mole number and the acid type weight ratio of the carboxyl group to which no alkylene oxide is added. It is described that it can act effectively against. However, since this technology consists of two types of copolymers, a copolymer having a small contribution to dispersion is added, and the amount of copolymer required to stabilize dispersion tends to increase. Is not sufficient from an economic point of view.

JP-A-6-191918 JP 2000-191356 A JP 2002-187755 A JP 2003-128738 A JP 11-246250 A JP 2006-298761

The object of the present invention is to provide good fluidity and reduce viscosity for a cement composition having a low water powder ratio such as a water powder ratio of less than 20%. An object of the present invention is to provide a copolymer as a cement dispersant which has no excessive setting delay and is excellent in strength development. In addition, an object of the present invention is to provide a cement composition capable of reducing self-shrinkage, which is a problem in concrete having a low water cement ratio. Furthermore, another object of the present invention is to blend the above cement dispersant into concrete, mortar or the like in which the water powder ratio is less than 20% in which an admixture having a specific surface area of more than 10,000 cm ² / g is blended. It is providing the cement composition which becomes.

  As a result of intensive studies in view of the above-mentioned situation, the present inventor exhibits high dispersibility even in a cement composition having a low water-powder ratio by using a copolymer having a specific structural unit. As a result, it was found that there is little setting delay and excellent strength development, and the present invention has been completed.

（ここで、Ｒ^１、Ｒ^４はそれぞれ独立に水素またはメチル基を、Ｒ^２、Ｒ^３はＣ１〜４のアルキレン基を、ＯＡはＣ２又は３のオキシアルキレン基を、ｘ、ｙはそれぞれ独立に０または１を、ｚは６〜６０を表す。）
（Ｂ）のモル比率は３０〜９０％であって、下式（Ｂ−１）又は（Ｂ−２）で表されるいずれか１種若しくは２種以上であって、
（Ｂ−１）

（ここで、Ｒ^５は水素またはＣＯＯＹを、Ｒ^６は水素又はメチル基を、Ｙは水素又はＣ１〜８の脂肪族炭化水素を表す。）
（Ｂ−２）

（ここでＡは酸素またはＮＲ^７を表し、Ｒ^７は水素、Ｃ１〜２０のアルキル基、Ｃ６〜２０のアリール基、スルホニル基、又はスルファニル基のいずれかを表す。）
（Ｃ）のモル比率は０〜２０％であって、下式で表され、

（ここで、Ｒ^９は水素又はメチル基を、ｐは０，１，２を、ｑは０又は１を表す。ただしｐ、ｑの少なくともいずれか一方は０である。Ｒ^１０はＣ１〜４のアルキル基、又はＣ１〜４のヒドロキシアルキル基を、Ｓは水素、メチル基、又はＣＯＯＲ^１１を表し、Ｒ^１１は水素、Ｃ１〜４のアルキル基、又はＣ１〜４のヒドロキシアルキル基を表す。）
かつ（Ａ）、（Ｂ）、（Ｃ）のモル比率は合計１００％であることを特徴とする。 That is, the copolymer according to the present invention exhibits high dispersibility even in a cement composition having a low water powder ratio by adding it as a cement dispersant to the cement composition, suppresses an increase in viscosity, and has a setting delay. It exhibits little strength development and consists of the following repeating units (A) and (B) as cement dispersants, or (A), (B) and (C), A copolymer having an average molecular weight of 5,000 to 100,000,
The molar ratio of (A) is 10 to 50%, and (A) is two or more represented by the following formulas,

(Wherein R ¹ and R ⁴ are each independently hydrogen or a methyl group, R ² and R ³ are C 1-4 alkylene groups, OA is a C 2 or 3 oxyalkylene group, and x and y are each independently 0 represents 1 or z, and z represents 6 to 60.)
The molar ratio of (B) is 30 to 90%, which is any one or two or more represented by the following formula (B-1) or (B-2),
(B-1)

(Here, R ⁵ represents hydrogen or COOY, R ⁶ represents hydrogen or a methyl group, and Y represents hydrogen or a C1-8 aliphatic hydrocarbon.)
(B-2)

(Here, A represents oxygen or NR ⁷ , and R ⁷ represents hydrogen, a C1-20 alkyl group, a C6-20 aryl group, a sulfonyl group, or a sulfanyl group.)
The molar ratio of (C) is 0 to 20%, and is represented by the following formula:

(Here, R ⁹ represents hydrogen or a methyl group, p represents 0, 1, 2 and q represents 0 or 1. However, at least one of p and q is 0. R ¹⁰ represents C1-4. alkyl group, or a hydroxyalkyl group of C1 -4, S represents hydrogen, methyl group, or COOR ^{11, R 11} represents hydrogen, an alkyl group of C1 -4, or C1 -4 hydroxyalkyl groups. )
And the molar ratio of (A), (B), (C) is 100% in total.

  In addition, the copolymer according to the present invention is composed of two or more types of repeating (A) in which Z is in the range of 6 to 20 (Z1) and in the range of 20 to 60 (Z2). Each molar ratio is 20: 80-80: 20.

  Further, in the copolymer of the present invention, the molar ratio (A): ((B) + (C)) of the total amount of (A), (B) and (C) is 1: 1 to 1: 4. It is a range.

  The copolymer of the present invention is characterized in that the ratio of (B-2) is 50 mol% or less with respect to the whole (B).

  The present invention is also characterized in that it is used for a cement composition having a water powder ratio of 20% or less, which is a ratio of water weight to powder weight.

  Moreover, this invention relates to the admixture for concrete characterized by including the copolymer of this invention.

（ここで、Ｒ^１２は炭素数１から８の炭化水素を、Ｒ^１３は水素又はＣ１〜４の炭化水素を、ＡＯは炭素数２及び／又は３のアルキレンオキシドを、ｕはアルキレンオキシドの付加モル数で、１から２０の整数を表す。） Furthermore, it is related with the admixture for concrete characterized by including (D) represented by the following Formula.

(Where R ¹² is a hydrocarbon having 1 to 8 carbon atoms, R ¹³ is hydrogen or a C 1-4 hydrocarbon, AO is an alkylene oxide having 2 and / or 3 carbon atoms, and u is an addition of an alkylene oxide. Represents an integer from 1 to 20 in terms of moles.)

  Moreover, this invention relates to the cement composition characterized by including the copolymer of this invention.

  The present invention also relates to a cement composition characterized in that a water powder ratio, which is a ratio of water weight to total powder weight used in the cement composition, is 20% or less.

  Moreover, this invention relates to the cement composition characterized by including (D) represented by the following Formula further.

（ここで、Ｒ^１２は炭素数１から８の炭化水素を、Ｒ^１３は水素又はＣ１〜４の炭化水素を、ＡＯは炭素数２および／または３のアルキレンオキシドを、ｕはアルキレンオキシドの付加モル数で、１から２０の整数を表す。）
さらに本発明は、上の本発明のセメント分散剤としての共重合体を、全粉体重量に対する重量比で０．１０％から１．０％の範囲で含有することを特徴とするセメント組成物に関する。

(Where R ¹² is a hydrocarbon having 1 to 8 carbon atoms, R ¹³ is hydrogen or a C 1-4 hydrocarbon, AO is an alkylene oxide having 2 and / or 3 carbon atoms, and u is an addition of an alkylene oxide. Represents an integer from 1 to 20 in terms of moles.)
Furthermore, the present invention contains the above copolymer as a cement dispersant of the present invention in a weight ratio of 0.10% to 1.0% with respect to the total powder weight. About.

In the present invention, the cement composition contains an ultrafine particle powder having a specific surface area exceeding 10,000 cm ² / g in a range of 5 wt% to 20 wt% with respect to the total powder weight. The present invention relates to a cement composition characterized in that a water powder ratio, which is a ratio of water weight to the weight of all powders including fine particles, is 20% or less.

Further, according to the present invention, the cement composition contains an ultrafine particle powder having a specific surface area exceeding 10,000 cm ² / g in a range of 5 wt% to 20 wt% with respect to the total powder weight, Separately, the inorganic powder expansion material is contained in the range of 1 to 10% by weight with respect to the total powder amount, and the water weight with respect to the total powder weight including the ultrafine particles and the inorganic powder expansion material It is related with the cement composition characterized by the water powder ratio which is a ratio of 20% or less.

  The copolymer according to the present invention has a specific constitutional unit, and thus exhibits high dispersibility even in a cement composition having a low water-powder ratio by using it as a cement dispersant for a cement composition. Is suppressed, the setting delay is small, and the strength development is excellent.

The measurement result of the self-shrink property of the concrete in the mixing | blending C-2 of this invention in an Example is shown.

(Copolymer)
The copolymer of the present invention exhibits excellent performance as a cement dispersant, and is characterized by comprising at least two specific types of repeating units (A) and (B) as described in detail below. . Furthermore, a copolymer with a third repeatable unit (C) that can be polymerized is also included.

  The weight average molecular weight of the copolymer of the present invention is not particularly limited and can be obtained in a wide range using a commonly known polymerization method. Specifically, a cement dispersant using the copolymer of the present invention is used. The weight average molecular weight in terms of polyethylene glycol (PEG) measured by gel permeation chromatography (GPC) is preferably 5,000 to 100,000, and more preferably It is 10,000 to 70,000, particularly preferably 20,000 to 40,000.

  The structure of the repeating unit (monomer) (A) that can be preferably used in the present invention is as follows.

（ここで、Ｒ^１、Ｒ^４はそれぞれ独立に水素またはメチル基を、Ｒ^２、Ｒ^３はＣ1〜４のアルキレン基を、ＯＡはＣ２又は３のオキシアルキレン基を、ｘ、ｙはそれぞれ独立に０または１を、ｚは６〜６０を表す）。

(Wherein R ¹ and R ⁴ are each independently hydrogen or a methyl group, R ² and R ³ are C 1-4 alkylene groups, OA is a C 2 or 3 oxyalkylene group, and x and y are each independently And 0 represents 1 and z represents 6 to 60).

Here, as the repeating unit (A), the alkylene oxide addition mole number Z of (OA) _Z is not limited to one type but may include two or more different types.

  In general, the larger the ethylene oxide addition mole number (Z) in the structural unit (A), the higher the three-dimensional repulsive force and the higher the dispersibility. However, as Z increases, the viscosity of the cement composition increases as the copolymer increases in molecular weight, and when Z increases, the time required for the molecular chain to extend in the cement composition increases. The time for exhibiting the required dispersibility, that is, the time required for mixing the cement composition becomes longer. On the other hand, when Z is small, the dispersibility is low, but the viscosity of the cement composition can be kept low, and the time required to exhibit the required dispersibility tends to be short. When Z is small, the setting time of the cement composition tends to be delayed. Thus, the performance of the copolymer varies greatly depending on the length of Z, and the degree of influence of the added mole number of ethylene oxide on the performance of the copolymer is very large. From such a viewpoint, in order to obtain a desired effect, it is possible to select two or more structural units (A) having different ethylene oxide addition mole numbers (Z) in the copolymer of the present invention.

  Specifically, as the two or more structural units (A) having different Z, the range of Z is from 1 to 2 or more of 6 to 20, which is a low addition mole number, and from 20 which is a high addition mole number. It is preferable that it is 1 type or 2 types or more which are the range of 60, and it is preferable that the molar ratio exists in the range of 20:80 to 80:20 of low addition mole number: high addition mole number. Among them, one or two or more structural units (A) having a low addition mole number in the range of 6 to 12 and one or two or more structural units (A) having a high addition mole number in the range of 30 to 50 ( More preferably, A) is a ratio of 40:60 to 60:40.

  The component (A), which is a component of the copolymer of the present invention, is represented by the general formula (A). Specifically, (poly) oxyethylene vinyl ether, (poly) oxyethylene (meth) allyl ether , (Poly) oxyethylene butenyl ether, (poly) oxyethylene methylbutenyl ether, (poly) oxypropylene vinyl ether, (poly) oxypropylene (meth) allyl ether, (poly) oxypropylene butenyl ether, (poly) Oxypropylene methylbutenyl ether, (poly) oxyethylene (poly) oxypropylene vinyl ether, (poly) oxyethylene (poly) oxypropylene (meth) allyl ether, (poly) oxyethylene (poly) oxypropylene butenyl ether, ( Poly) oxyethylene (poly) oxypropylene methylbutenyl ether, methoxy (poly ) Oxyethylene vinyl ether, methoxy (poly) oxyethylene (meth) allyl ether, methoxy (poly) oxyethylene butenyl ether, methoxy (poly) oxyethylene methylbutenyl ether, methoxy (poly) oxypropylene vinyl ether, methoxy (poly) Oxypropylene (meth) allyl ether, methoxy (poly) oxypropylene butenyl ether, methoxy (poly) oxypropylene methylbutenyl ether, methoxy (poly) oxyethylene (poly) oxypropylene vinyl ether, methoxy (poly) oxyethylene (poly ) Oxypropylene (meth) allyl ether, methoxy (poly) oxyethylene (poly) oxypropylene butenyl ether, methoxy (poly) oxyethylene (poly) oxypropylene methylbutenyl ether, hydroxymethyl-biphenyl Nyl ether polyethylene glycol adduct, hydroxymethyl- (meth) allyl ether polyethylene glycol adduct, hydroxymethyl-butenyl ether polyethylene glycol adduct, hydroxymethyl-methylbutenyl ether polyethylene glycol adduct, hydroxypropyl-vinyl ether polyethylene glycol adduct , Hydroxypropyl- (meth) allyl ether polyethylene glycol adduct, hydroxypropyl-butenyl ether polyethylene glycol adduct, hydroxypropyl-methylbutenyl ether polyethylene glycol adduct, hydroxybutyl-vinyl ether polyethylene glycol adduct, hydroxybutyl- (Meth) allyl ether polyethylene glycol adduct, hydroxybuty -Butenyl ether polyethylene glycol adduct, hydroxybutyl-methylbutenyl ether polyethylene glycol adduct, hydroxymethyl-vinyl ether polypropylene glycol adduct, hydroxymethyl- (meth) allyl ether polypropylene glycol adduct, hydroxymethyl-butenyl ether polypropylene Glycol adduct, hydroxymethyl-methylbutenyl ether polypropylene glycol adduct, hydroxypropyl-vinyl ether polypropylene glycol adduct, hydroxypropyl- (meth) allyl ether polypropylene glycol adduct, hydroxypropyl-butenyl ether polypropylene glycol adduct, hydroxy Propyl-methylbutenyl ether polypropylene glycol Adduct, hydroxybutyl-vinyl ether polypropylene glycol adduct, hydroxybutyl- (meth) allyl ether polypropylene glycol adduct, hydroxybutyl-butenyl ether polypropylene glycol adduct, hydroxybutyl-methylbutenyl ether polypropylene glycol adduct, hydroxymethyl -Vinyl ether polyethylene glycol polypropylene glycol adduct, hydroxymethyl- (meth) allyl ether polyethylene glycol polypropylene glycol adduct, hydroxymethyl-butenyl ether polyethylene glycol polypropylene glycol adduct, hydroxymethyl-methylbutenyl ether polyethylene glycol polypropylene glycol adduct , Hydroxypropyl-bi Nyl ether polyethylene glycol polypropylene glycol adduct, hydroxypropyl- (meth) allyl ether polyethylene glycol polypropylene glycol adduct, hydroxypropyl-butenyl ether polyethylene glycol polypropylene glycol adduct, hydroxypropyl-methylbutenyl ether polyethylene glycol polypropylene glycol adduct , Hydroxybutyl-vinyl ether polyethylene glycol polypropylene glycol adduct, hydroxybutyl- (meth) allyl ether polyethylene glycol polypropylene glycol adduct, hydroxybutyl-butenyl ether polyethylene glycol polypropylene glycol adduct, hydroxybutyl-methylbutenyl ether polyethylene Glycol polypropylene glycol adduct, hydroxymethyl-vinyl ether methoxypolyethylene glycol adduct, hydroxymethyl- (meth) allyl ether methoxypolyethylene glycol adduct, hydroxymethyl-butenyl ether methoxypolyethylene glycol adduct, hydroxymethyl-methylbutenyl ether methoxy Polyethylene glycol adduct, hydroxypropyl-vinyl ether methoxypolyethylene glycol adduct, hydroxypropyl- (meth) allyl ether methoxypolyethylene glycol adduct, hydroxypropyl-butenyl ether methoxypolyethylene glycol adduct, hydroxypropyl-methylbutenyl ether methoxypolyethylene Glycol adduct, hydroxybutyl Nyl ether methoxypolyethylene glycol adduct, hydroxybutyl- (meth) allyl ether methoxypolyethylene glycol adduct, hydroxybutyl-butenyl ether methoxypolyethylene glycol adduct, hydroxybutyl-methylbutenyl ether methoxypolyethylene glycol adduct, hydroxymethyl- Vinyl ether methoxy polypropylene glycol adduct, hydroxymethyl- (meth) allyl ether methoxy polypropylene glycol adduct, hydroxymethyl-butenyl ether methoxy polypropylene glycol adduct, hydroxymethyl-methyl butenyl ether methoxy polypropylene glycol adduct, hydroxypropyl-vinyl ether Methoxypolypropylene glycol adduct, hydroxy Cypropyl- (meth) allyl ether methoxypolypropylene glycol adduct, hydroxypropyl-butenyl ether methoxypolypropylene glycol adduct, hydroxypropyl-methylbutenyl ether methoxypolypropylene glycol adduct, hydroxybutyl-vinyl ether methoxypolypropylene glycol adduct, hydroxybutyl -(Meth) allyl ether methoxy polypropylene glycol adduct, hydroxybutyl-butenyl ether methoxy polypropylene glycol adduct, hydroxybutyl-methylbutenyl ether methoxy polypropylene glycol adduct, hydroxymethyl-vinyl ether methoxy polyethylene glycol polypropylene glycol adduct, hydroxy Methyl- (meth) allylene Termethoxy polyethylene glycol polypropylene glycol adduct, hydroxymethyl-butenyl ether methoxy polyethylene glycol polypropylene glycol adduct, hydroxymethyl-methyl butenyl ether methoxy polyethylene glycol polypropylene glycol adduct, hydroxypropyl-vinyl ether methoxy polyethylene glycol polypropylene glycol adduct, Hydroxypropyl- (meth) allyl ether methoxypolyethylene glycol polypropylene glycol adduct, Hydroxypropyl-butenyl ether methoxypolyethylene glycol polypropylene glycol adduct, Hydroxypropyl-methylbutenyl ether methoxypolyethylene glycol polypropylene glycol adduct Hydroxybutyl-vinyl ether methoxypolyethylene glycol polypropylene glycol adduct, hydroxybutyl- (meth) allyl ether methoxypolyethylene glycol polypropylene glycol adduct, hydroxybutyl-butenyl ether methoxypolyethylene glycol polypropylene glycol adduct, hydroxybutyl-methylbutenyl ether methoxy Polyethylene glycol polypropylene glycol adduct, etc. can be exemplified, preferably (poly) oxyethylene vinyl ether, (poly) oxyethylene (meth) allyl ether, (poly) oxyethylene butenyl ether, (poly) oxyethylene methylbutenyl ether , Hydroxybutyl-vinyl ether polyethylene glycol adduct, hydroxybutyl- (meth) a Ether polyethylene glycol adducts, hydroxybutyl - butenyl ether polyethylene glycol adducts, hydroxybutyl - methyl butenyl ether polyethylene glycol adducts.

（ここで、Ｒ^５は水素またはＣＯＯＹを、Ｒ^６は水素又はメチル基を、Ｙは水素又はＣ１〜８の脂肪族炭化水素を表す。）
（Ｂ−２）

（ここでＡは酸素またはＮＲ^７を表し、Ｒ^７は水素、Ｃ１〜２０のアルキル基、Ｃ６〜２０のアリール基、スルホニル基、又はスルファニル基のいずれかを表す。）
本発明において（Ｂ）は、（Ｂ−１）と（Ｂ−２）なる特定構造を有する２種類からなるが、それらの比については特に制限はない。ただし本発明における共重合体の構成成分（Ｂ）のうちの一般式（Ｂ−２）で表される構成成分（Ｂ−２）の構成成分（Ｂ）に対する比率が高くなると、練り混ぜ初期における分散性の低く時間とともに分散性が増大する傾向が強く、低水粉体比のセメント組成物に対するセメント分散剤としては好ましくない。また、構成成分（Ｂ−２）の構成成分（Ｂ）に対する比率が低くなると、すなわち、一般式（Ｂ−１）で表される構成成分（Ｂ−１）の構成成分（Ｂ）に対する比率が高くなると、練り混ぜ直後からの分散性の劇的な低下（こわばり）が助長される為、好ましくない。これらの観点から、構成成分（Ｂ）中の構成成分（Ｂ−２）の比率は５０モル％以下であることが好ましく、さらに好ましくは４０％から５％であり、特に好ましくは３０％から１０％である。 The structure of the repeating unit (monomer) (B) that can be preferably used in the present invention is as follows, and consists of two types (B-1) and (B-2).
(B-1)

(Here, R ⁵ represents hydrogen or COOY, R ⁶ represents hydrogen or a methyl group, and Y represents hydrogen or a C1-8 aliphatic hydrocarbon.)
(B-2)

(Here, A represents oxygen or NR ⁷ , and R ⁷ represents hydrogen, a C1-20 alkyl group, a C6-20 aryl group, a sulfonyl group, or a sulfanyl group.)
In the present invention, (B) consists of two types having specific structures (B-1) and (B-2), but there is no particular limitation on the ratio thereof. However, when the ratio of the constituent component (B-2) represented by the general formula (B-2) to the constituent component (B) in the constituent component (B) of the copolymer in the present invention increases, The dispersibility is low and the tendency of the dispersibility to increase with time is strong, which is not preferable as a cement dispersant for a cement composition having a low water powder ratio. Further, when the ratio of the constituent component (B-2) to the constituent component (B) is decreased, that is, the ratio of the constituent component (B-1) represented by the general formula (B-1) to the constituent component (B) is increased. Higher values are not preferable because a dramatic decrease (stiffness) in dispersibility immediately after kneading is promoted. From these viewpoints, the ratio of the constituent component (B-2) in the constituent component (B) is preferably 50 mol% or less, more preferably 40% to 5%, and particularly preferably 30% to 10%. %.

  The component (B-1) which is a component of the copolymer of the present invention is represented by the general formula (B-1), specifically, acrylic acid, methacrylic acid, maleic acid, maleic acid monoalkyl ester , Maleic acid monoalkenyl ester, citraconic acid monoalkyl ester, citraconic acid monoalkenyl ester, and the like, preferably acrylic acid, methacrylic acid, and maleic acid.

  The component (B-2) which is a component of the copolymer of the present invention is represented by the general formula (B-2), specifically, maleic anhydride, citraconic anhydride, dimethylmaleic anhydride, maleimide N-alkylmaleimide, N-phenylmaleimide, N-alkylphenylmaleimide and the like, and maleic anhydride is particularly preferable.

  The copolymer of the present invention may further have a copolymerizable repeating unit (C) in addition to the above (A) and (B). (C) can be introduced into the copolymer comprising (A) and (B) as a spacer or a function-added site. In addition to its performance as a cement dispersant, it controls flow retention, defoaming, and shrinkage. Although it will not restrict | limit especially if there exists an effect which adds performances, such as a reduction | restoration property, Various well-known nonpolar alpha olefins and polar group substituted alpha olefins are mentioned.

  In the present invention, (C) is a compound represented by the following structure.

（ここで、Ｒ^９は水素又はメチル基を、ｐは０，１，２を、ｑは０又は１を表す。ただしｐ、ｑの少なくともいずれか一方は０である。Ｒ^１０は、Ｃ１〜４のアルキル基、又はＣ１〜４のヒドロキシアルキル基を、Ｓは水素、メチル基、又はＣＯＯＲ^１１を表し、Ｒ^１１は水素、Ｃ１〜４のアルキル基、又はＣ１〜４のヒドロキシアルキル基を表す。）
本発明の共重合体の構成成分である構成成分（Ｃ）は具体的には、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸プロピル、（メタ）アクリル酸ブチル、（メタ）アクリル酸ヒドロキシエチル、（メタ）アクリル酸ヒドロキシプロピル、（メタ）アクリル酸ヒドロキシブチル、（メタ）アリルアルコール、（メタ）アリルアルコールモノエチレングリコールエーテル、（メタ）アリルアルコールモノプロピレングリコールエーテル、（メタ）アリルアルコールモノブチレングリコールエーテル、３−メチル−３−ブテン−１−オール、３−メチル−３−ブテン−１−オールモノエチレングリコールエーテル、３−メチル−３−ブテン−１−オールモノプロピレングリコールエーテル、３−メチル−３−ブテン−１−オールモノブチレングリコールエーテル、マレイン酸ジアルキルなどが例示できる。

(Here, R ⁹ represents hydrogen or a methyl group, p represents 0, 1, 2 and q represents 0 or 1. However, at least one of p and q is 0. R ¹⁰ represents C1 to C1. 4 alkyl group, or a hydroxyalkyl group of C1 -4, S represents hydrogen, methyl group, or COOR ^{11, R 11} represents hydrogen, an alkyl group of C1 -4, or C1 -4 hydroxyalkyl groups .)
Specifically, the component (C) which is a component of the copolymer of the present invention is, specifically, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, Hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, (meth) allyl alcohol, (meth) allyl alcohol monoethylene glycol ether, (meth) allyl alcohol monopropylene glycol ether, (Meth) allyl alcohol monobutylene glycol ether, 3-methyl-3-buten-1-ol, 3-methyl-3-buten-1-ol monoethylene glycol ether, 3-methyl-3-buten-1-ol mono Propylene glycol ether, 3-methyl-3-butene- - All mono butylene glycol ethers, such as dialkyl maleate can be exemplified.

  In the copolymer of the present invention, the molar ratio of these repeating units (A), (B), and (C) is not particularly limited and can be selected so that the total is 100%.

  More specifically, when the copolymer in the present invention comprises (A) and (B), it is preferable that (A) is in the range of 10 to 50 mol%. More preferably, (A) is in the range of 25 to 50 mol%, particularly preferably 40 to 50 mol%.

  Furthermore, in addition to (A) and (B), other copolymerizable (C) can be included. Inclusion of (C) makes it possible to exhibit properties such as control of fluidity retention, defoaming properties, and shrinkage reduction, but the amount can be appropriately selected according to the purpose. It is possible to include (C) in a range of 20 mol% relative to (A) and (B).

Furthermore, the molar ratio of the total amount of the structural unit (B) and the structural unit (C) to the structural unit (A) of the copolymer in the present invention is (A): ((B) + (C)) from 1: 1. A range of 1: 9 is preferred. When the proportion of the structural unit (A) is higher than this range, the dispersibility immediately after kneading is low, and the behavior becomes such that the dispersibility is exhibited later, which is not preferable. On the other hand, if the ratio of ((B) + (C)) is higher than this range, a sudden loss of dispersibility immediately after kneading becomes remarkable, which is not preferable. From this viewpoint, the ratio is more preferably in the range of 1: 1 to 1: 4, and particularly preferably in the range of 1: 1.5 to 1: 3.
(Manufacture of copolymer)
The method for producing a copolymer in the present invention is not particularly limited, and any conventional copolymerization method by general radical polymerization can be used. In addition, although there is no restriction | limiting in particular also about the confirmation method of a weight average molecular weight, The measurement by a conventionally well-known GPC method is preferable. Specific GPC analysis measurement conditions in the present invention were described in the following examples.
(Cement composition)
The cement composition of the present invention comprises the copolymer of the present invention described above as a cement dispersant. Here, the cement composition can be used without limitation as long as it is generally known, and concrete examples thereof include cement paste, mortar, grout, concrete and the like. When the copolymer of the present invention is used as a cement dispersant, the addition amount is not particularly limited, but is in the range of 0.10% to 1.0% by weight with respect to the total powder weight including ultrafine powder. It is preferable that When the addition amount is low, the dispersibility cannot be exhibited sufficiently, and when the addition amount is high, there is a possibility of adverse effects such as an extreme delay of setting or separation of the cement composition, which is not preferable.

In particular, as the cement composition of the present invention, the ultrafine particle powder having a specific surface area of more than 10,000 cm ² / g is contained in the range of 5% by weight to 20% by weight with respect to the total powder weight. The water powder ratio, which is the ratio of the water weight to the weight of all the powders containing, may be 20% or less, and the cement dispersant of the present invention is weighted with respect to the weight of all powders containing the ultrafine particles. What is contained in the range of 0.10% to 1.0% in a ratio is mentioned.

Furthermore, the cement composition according to the present invention contains an ultrafine particle powder having a specific surface area of more than 10,000 cm ² / g in a range of 5 wt% to 20 wt% with respect to the total powder weight, and further an inorganic type It is a ratio of water weight to the weight of all powders containing the powder expansion material in the range of 1 to 10% by weight with respect to the total powder amount and including the ultrafine particles and the inorganic powder expansion material. The water powder ratio is 20% or less, and the cement dispersant of the present invention is 0.10% to 1.0% by weight with respect to the weight of all powders including the ultrafine particles and the inorganic powder expansion material. What is contained in the range of% is mentioned.

When producing ultra-high-strength concrete, it is common to use an ultrafine particle powder having a specific surface area measured by a Blaine specific surface area meter such as silica fume exceeding 10,000 cm ² / g. This ultrafine powder contributes to the fluidity and strength development of ultra-high-strength concrete by the ball bearing effect or filler effect derived from its shape. The specific surface area increases excessively, causing an increase in viscosity, an increase in the amount of dispersant required, and the like. Therefore, the blending amount of the ultrafine particle powder needs to be in the range of 5 wt% to 20 wt%, but is preferably in the range of 7 wt% to 15 wt%.

（ここで、Ｒ^１２は炭素数１から８の炭化水素を、Ｒ^１３は水素又はＣ１〜４の炭化水素を、ＡＯは炭素数２および／または３のアルキレンオキシドを、ｕはアルキレンオキシドの付加モル数で、１から２０の整数を表す。）
（Ｄ）を加えることで低水粉体比のセメント組成物において顕著である自己収縮を低減する効果をさらに奏することが可能である。かかる効果の観点から、（Ｄ）の添加量は、セメント組成物中の全粉体重量に対して０．１〜２．０重量％の範囲が好ましい。
係る自己収縮を低減する目的において、（Ｄ）は、一般式（Ｄ）におけるＲ^１２が炭素数1〜４のアルキル基、アルケニル基、アルキニル基であることが好ましく、Ｒ^１３が水素であることが好ましく、ＡＯがエチレンオキサイドであることが好ましく、ｕが１〜１０であることが好ましい。
以下に本発明の実施例を挙げ、さらに詳しく本発明を説明する。本発明はこれら実施例に限定されるものではない。 In addition, the cement composition according to the present invention includes the above-described cement composition,
Formula (D)

(Where R ¹² is a hydrocarbon having 1 to 8 carbon atoms, R ¹³ is hydrogen or a C 1-4 hydrocarbon, AO is an alkylene oxide having 2 and / or 3 carbon atoms, and u is an addition of an alkylene oxide. Represents an integer from 1 to 20 in terms of moles.)
By adding (D), it is possible to further exert the effect of reducing the self-shrinkage that is remarkable in the cement composition having a low water powder ratio. From the viewpoint of this effect, the amount of (D) added is preferably in the range of 0.1 to 2.0% by weight with respect to the total powder weight in the cement composition.
For the purpose of reducing such self-shrinkage, in (D), R ¹² in the general formula (D) is preferably an alkyl group having 1 to 4 carbon atoms, an alkenyl group, or an alkynyl group, and R ¹³ is hydrogen. Is preferable, AO is preferably ethylene oxide, and u is preferably 1-10.
Examples of the present invention will be given below to explain the present invention in more detail. The present invention is not limited to these examples.

  Furthermore, the cement composition in the present invention can be used in combination with generally used additives for concrete or compounds used as raw materials thereof, specifically, AE agent, antifoaming agent, AE water-reducing agent, high-performance AE water-reducing agent, water-reducing agent, high-performance water-reducing agent, setting accelerator, quick setting agent, setting retarding agent, early strengthening agent, and resin acid esters generally used as raw materials thereof, Polyalkylene glycol alkyl sulfate, tall oil fatty acid saponified product, polyalkylene glycol compound, mineral oil, silicone antifoam, lignin sulfonate, polyol complex, β naphthalene sulfonate, melamine sulfonate, polycarboxylic acid Salts, aminosulfonates, rhodan salts, nitrites, gluconates, sugars, trialkanolamines and the like.

(Manufacture of copolymer)
The copolymer according to the present invention was produced by the following method. The raw materials used and the resulting copolymers are summarized in Tables 1 and 2 as P-1 to P-29.

  In a reaction vessel equipped with a stirrer, thermometer, pH electrode and raw material inlet, 880 parts by weight of hydroxybutyl-vinyl ether polyethylene oxide adduct (addition number 22.5) and hydroxybutyl-vinyl ether polyethylene oxide adduct (addition number) 42.5) 400 parts by weight and 833.3 parts by weight of water were added and stirring was started. In a separate container, 115.2 parts by weight of acrylic acid, 19.2 parts by weight of maleic anhydride, 10.1 parts by weight of 3-mercaptopropionic acid and 404.7 parts by weight of water are mixed to prepare a monomer solution. did. 100 parts by weight of this monomer solution was put into a reaction vessel, and further 19.1 parts by weight of 30% hydrogen peroxide and 0.31 part by weight of ferrous sulfate heptahydrate were added to initiate the reaction. . During the reaction, stirring was continued while adjusting the temperature to 30 ° C. or less and the pH to 6.0 or less, and 300 parts by weight of the reducing agent made into the remaining monomer solution and 3% aqueous solution was added at a predetermined rate. The reaction was allowed to proceed. After the entire amount of the monomer solution has been charged, the entire remaining reducing agent aqueous solution is charged to complete the reaction, the pH is adjusted to 6.5 with an aqueous sodium hydroxide solution, and a copolymer P-1 having an aqueous solid content concentration of 45% is obtained. Obtained. In the same manner, copolymers P-2 to P-29 having an aqueous solid content concentration of 45% were obtained.

（セメント組成物の製造）
混和剤： 表３にまとめた。ここでレオビルドＳＰ８ＨＵは、ＢＡＳＦポゾリス社製超高強度コンクリート用高性能減水剤であり、各混和剤中の共重合体の濃度は、レオビルドＳＰ８ＨＵの固形分濃度と同等になるように調整した。 In addition, the following GPC measurement conditions were used for the weight average molecular weight.
Column: Two SB804s manufactured by Shodex were connected in series.
Mobile phase: 0.1N sodium sulfate aqueous solution and methanol 8: 2 mixed solution was used.
Column temperature: 60 degrees Celsius Flow rate: 0.8 ml / min Detector: Differential refractometer (RI detector)
Reference material: Polyethylene glycol

(Manufacture of cement composition)
Admixtures : Summarized in Table 3. Here, Leo build SP8HU is a high-performance water reducing agent for ultra-high strength concrete manufactured by BASF Pozzolith, and the concentration of the copolymer in each admixture was adjusted to be equal to the solid content concentration of Leo build SP8HU.

ただし、各配合比率が１００％に満たない場合は、１００％になるように水で希釈した。

セメント： 宇部三菱セメント社製 シリカフュームセメント （ＳＦＣ：密度３．０８
ｇ／ｃｍ^３）
デイ・シイ社製 ＶＫＣ１００ＳＦ （ＶＫＣ：密度２．９９ｇ／ｃｍ^３）
細骨材： 大井川水系産陸砂 （密度：２．５９ｇ／ｃｍ^３、粗粒率：２．６９）
粗骨材： 青梅産砕石 （密度２．６５ｇ／ｃｍ^３、粗粒率：６．６０、粗骨材最大寸法
：２０ｍｍ）
膨張材： 太平洋マテリアル社製 エクスパン （Ｅｘ： 密度：３．１４ｇ／ｃｍ^３、
比表面積３５００ｃｍ^２／ｇ）
水： 上水道水

上記の材料を用いて表４に示す配合でモルタル及びコンクリート試験を行った。

However, when each compounding ratio was less than 100%, it diluted with water so that it might become 100%.

Cement : Silica fume cement (SFC: density 3.08) manufactured by Ube Mitsubishi Cement Co., Ltd.
g / cm ³ )
VKC100SF (VKC: density 2.99 g / cm ³ ) manufactured by Day Shi
Fine aggregate: Oi river water production Rikusuna (density: 2.59 g / cm ^3, Sotsuburitsu: 2.69)
Coarse aggregate : Ome crushed stone (density 2.65 g / cm ³ , coarse particle rate: 6.60, coarse aggregate maximum dimension
: 20mm)
Expandable material : Expanse (Ex: Density: 3.14 g / cm ³⁾
(Specific surface area 3500 cm ² / g)
Water : tap water

Mortar and concrete tests were conducted using the above materials with the formulation shown in Table 4.

モルタルの練混ぜ： ＡＳＴＭモルタルミキサに所定量の混和剤を含む水１４０重量部（Ｍ−２の場合は１５０重量部）、セメント１０００重量部を投入し、３分間低速にて練混ぜを行った後、さらに細骨材４００重量部（Ｍ−２の場合は５００重両部）を投入し３分間練混ぜ、評価用のモルタルを調整した。
モルタルフローの測定： 調整したモルタルは、ＪＩＳ Ｒ ５２０１：１９９７に記載のモルタルフローコーンを使用し、静置状態におけるモルタルフローを測定した。
コンクリートの練混ぜ： 二軸強制練りミキサに、表４に示す配合に従い、所定量の細骨材、セメント、膨張材を投入し、１０秒空練を行った後に、所定量の混和剤を含む練混ぜ水を投入し、５分間練混ぜた。その後所定量の粗骨材を投入し、３分間練混ぜを行い評価用のコンクリートを調整した。
コンクリートの試験：
スランプフロー：ＪＩＳ Ａ １１５０：２００７、空気量：ＪＩＳ Ａ １１２８：２００５
圧縮強度：ＪＩＳ Ａ １１３２：２００６により作製した直径１０ｃｍ高さ２０ｃｍの円柱供試体を所定の期間２０℃の水中にて養生し、ＪＩＳ Ａ １１０８：２００６により圧縮強度を測定した。

Mixing of mortar: An ASTM mortar mixer was charged with 140 parts by weight of water containing a predetermined amount of admixture (150 parts by weight in the case of M-2) and 1000 parts by weight of cement, and kneaded at a low speed for 3 minutes. Thereafter, 400 parts by weight of fine aggregate (500 parts in the case of M-2) was added and mixed for 3 minutes to prepare an evaluation mortar.
Measurement of mortar flow : As the adjusted mortar, a mortar flow cone described in JIS R 5201: 1997 was used, and the mortar flow in a stationary state was measured.
Concrete mixing : A predetermined amount of fine aggregate, cement, and expansion material are added to a biaxial forced mixing mixer according to the formulation shown in Table 4, and after 10 seconds of kneading, a predetermined amount of admixture is included. Mixing water was added and mixed for 5 minutes. After that, a predetermined amount of coarse aggregate was added and mixed for 3 minutes to prepare concrete for evaluation.
Concrete testing :
Slump flow: JIS A 1150: 2007, Air volume: JIS A 1128: 2005
Compressive strength: A cylindrical specimen having a diameter of 10 cm and a height of 20 cm prepared according to JIS A 1132: 2006 was cured in water at 20 ° C. for a predetermined period, and the compressive strength was measured according to JIS A 1108: 2006.

Self-shrinkage: A 10 cm × 10 cm × 40 cm square column specimen embedded with an embedded strain gauge was covered with aluminum tape, and the amount of strain of the specimen was measured for a predetermined period with a data processing device.
(result)
Table 5 summarizes the admixtures used and the amounts required to obtain a mortar flow of 280 mm. Here, the addition amount is a weight ratio (%) of the admixture to the total powder amount. X indicates that a mortar flow of 280 mm was not obtained even when the addition amount was increased. From the results of Table 5, the following was found.

配合Ｍ−１において、各混和剤を使用した時に、２８０ｍｍのモルタルフローを得るのに必要な混和剤の添加量を比較した。市販超高強度コンクリート用高性能ＡＥ減水剤であるＡｄ−３２がセメント重量に対して１．７％必要とするのに対して、本発明品である共重合体を含むＡｄ−１〜２４はいずれも必要とする使用量が少なくなったことから、本発明品は既存の市販品と比較してより効果的に分散性を発揮していることがわかった。

In Formulation M-1, when each admixture was used, the amount of admixture required to obtain a 280 mm mortar flow was compared. While Ad-32, which is a high-performance AE water reducing agent for ultra-high-strength concrete on the market, requires 1.7% of the cement weight, Ad-1 to 24 containing the copolymer of the present invention is Since the amount of use required for each of them was reduced, it was found that the product of the present invention exhibited dispersibility more effectively than the existing commercial product.

  The copolymer contained in Ad-25 has one mole of addition of elene oxide of 4, in which case the dispersibility is not sufficient, and side chains of different chain lengths are not shared in the same molecule, Also in the case of Ad-28 using two types of copolymers having different side chain lengths, the amount of admixture added to obtain equivalent dispersibility was high.

  Ad-26 by a copolymer having a single side chain length and, in the extreme case, Ad-27 by a copolymer whose blending ratio of constitutional units is not within the range of the present invention, mortar flow of 280 mm, no matter how much the addition amount is increased. I could not get.

  This tendency is the same in the blending of M-2, and the present invention gives sufficient dispersibility with a low addition amount to a cement composition with a low water cement ratio using a commercial cement blended with ultrafine particles. I knew it was possible.

  Table 6 summarizes the results of the concrete test.

コンクリート試験をＣ−１、Ｃ−２およびＣ−３の配合にて行った。いずれの配合においてもモルタルでの実験結果と同様に、本発明品は、市販超高強度コンクリート用高性能減水剤と比較して、少ない添加量で所定の流動性を付与できた。

A concrete test was conducted with a blend of C-1, C-2 and C-3. As with the experimental results with mortar, the product of the present invention was able to impart a predetermined fluidity with a small amount of addition as compared with a commercially available high-performance water reducing agent for ultra-high-strength concrete.

  In addition, the product of the present invention has a higher fluidity retention effect than commercial products, and is effective in maintaining the flow during the transportation time from the ready-con factory to the construction site or when it is actually used in concrete. there were.

  In addition, the product of the present invention has higher strength development than the commercially available product, and particularly has high strength development at the age of 1 day. This is because the setting of the concrete is not excessively delayed, and the long-term strength is equal to or higher than that of a commercially available product. Therefore, it was found that ultra-high strength concrete that can be easily managed during construction can be provided.

  Furthermore, in FIG. 1, the measurement result of the self-shrink property of the concrete in the mixing | blending C-2 was shown.

  From the figure, it was found that the ultra-high-strength concrete was able to reduce self-shrinkage in the inventive products Ad-30 and Ad-31 to which the compound D was added as compared with the commercially available products.

  By blending the copolymer of the present invention as a cement dispersant, a cement that exhibits high dispersibility even at a low water powder ratio, suppresses increase in viscosity, has low setting delay, and has excellent strength development. It becomes possible to obtain a composition.

Claims (13)

The cement dispersant is composed of the following repeating units (A), (B), or (A), (B), (C), and having a weight average molecular weight of 5,000 to 100,000. A polymer comprising:
The molar ratio of (A) is 10 to 50%, and (A) is two or more represented by the following formulas,

(Wherein R ¹ and R ⁴ are each independently hydrogen or a methyl group, R ² and R ³ are C 1-4 alkylene groups, OA is a C 2 or 3 oxyalkylene group, and x and y are each independently 0 represents 1 or z, and z represents 6 to 60.)
The molar ratio of (B) is 30 to 90%, which is any one or two or more represented by the following formula (B-1) or (B-2),
(B-1)

(Here, R ⁵ represents hydrogen or COOY, R ⁶ represents hydrogen or a methyl group, and Y represents hydrogen or a C1-8 aliphatic hydrocarbon.)
(B-2)

(Here, A represents oxygen or NR ⁷ , and R ⁷ represents hydrogen, a C1-20 alkyl group, a C6-20 aryl group, a sulfonyl group, or a sulfanyl group.)
The molar ratio of (C) is 0 to 20%, and is represented by the following formula:

(Here, R ⁹ represents hydrogen or a methyl group, p represents 0, 1, 2 and q represents 0 or 1. However, at least one of p and q is 0. R ¹⁰ represents C1 to C1. 4 alkyl group, or a hydroxyalkyl group of C1 -4, S represents hydrogen, methyl group, or COOR ^{11, R 11} represents hydrogen, an alkyl group of C1 -4, or C1 -4 hydroxyalkyl groups .)
And the molar ratio of (A), (B), (C) is 100% in total.   Repeat (A) is composed of two or more of Z in the range of 6 to 20 (Z1) and 20 to 60 (Z2), each having a molar ratio of 20:80 to The copolymer as a cement dispersant according to claim 1, wherein the copolymer is 80:20.   The molar ratio (A): ((B) + (C)) of the total amount of (A), (B) and (C) is in the range of 1: 1 to 1: 4, The copolymer as a cement dispersing agent of Claim 1 or 2.   The copolymer as a cement dispersing agent of any one of Claims 1-3 whose ratio of (B-2) is 50 mol% or less with respect to the whole (B).   The copolymer according to any one of claims 1 to 4, which is used for a cement composition having a water powder ratio of 20% or less, which is a ratio of water weight to powder weight.   A concrete admixture comprising the copolymer as a cement dispersant according to any one of claims 1 to 5. Furthermore, (D) represented by the following Formula is contained, The concrete admixture of Claim 6 characterized by the above-mentioned.

(Where R ¹² is a hydrocarbon having 1 to 8 carbon atoms, R ¹³ is hydrogen or a C 1-4 hydrocarbon, AO is an alkylene oxide having 2 and / or 3 carbon atoms, and u is an addition of an alkylene oxide. Represents an integer from 1 to 20 in terms of moles.)   A cement composition comprising the copolymer as a cement dispersant according to any one of claims 1 to 5.   The cement composition according to claim 8, wherein a water powder ratio, which is a ratio of water weight to total powder weight used in the cement composition, is 20% or less.   The cement composition according to claim 8 or 9, comprising (D).   The copolymer as a cement dispersant according to any one of claims 1 to 5 is contained in a range of 0.10% to 1.0% by weight ratio to the total powder weight. The cement composition according to any one of 10 above. The cement composition contains an ultrafine particle powder having a specific surface area exceeding 10,000 cm ² / g in a range of 5% by weight to 20% by weight with respect to the total powder weight, and includes all the ultrafine particles. The cement composition according to any one of claims 8 to 11, wherein a water powder ratio, which is a ratio of water weight to powder weight, is 20% or less. The cement composition contains an ultrafine particle powder having a specific surface area exceeding 10,000 cm ² / g in a range of 5 wt% to 20 wt% with respect to the total powder weight. Water containing a body expansion material in a range of 1 to 10% by weight with respect to the total amount of powder and being a ratio of water weight to the weight of all powders including the ultrafine particles and the inorganic powder expansion material The cement composition according to any one of claims 8 to 12, wherein the powder ratio is 20% or less.

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