JP2019112251A - Admixture for centrifugally-formed concrete and cement composition containing the same - Google Patents

Abstract

To provide an admixture for centrifugally-formed concrete, and a cement composition containing the same, which can suppress the reduction in strength of the inner portion, reduce the molding time, and further obtain integral deformability.SOLUTION: An admixture for the centrifugally-formed concrete comprises a polycondensate having at least one structural unit (I), at least one structural unit (II), and at least one structural unit (III). The structural unit (I) is an aromatic moiety having a polyether side chain having a specific number and kind of alkylene glycol units; the structure unit (II) is an aromatic moiety having at least one phosphoric acid ester group and/or its salt, and the molar ratio of the structural unit (II) to the structural unit (I) is a specific ratio; and the structure unit (III) is at least one methylene unit (-CH-), the methylene unit may be bound to a specific aromatic group by binding to the two aromatic ring units of the structural unit (I) and the structural unit (II), to result in the polycondensate of a specific weight average molecular weight.SELECTED DRAWING: None

Description

  The present invention relates to an admixture applied to centrifugally-formed concrete, in particular, a chemical admixture applied to centrifugally-formed concrete and a cement composition containing the same.

  When manufacturing hollow concrete molded articles, such as concrete piles, utility poles, fume tubes, etc., a method of centrifugally forming concrete is widely used. The centrifugal molding method can produce a solid concrete molded article having a hollow structure and can prevent air bubbles from remaining on the outer surface of the concrete molded article, thereby producing a concrete molded article having a smooth skin surface. On the other hand, the method of centrifugal molding not only limits the manufacturing equipment, but also tends to produce a fragile substance (so-called sorrow) containing water and a small amount of cement on the inside of the concrete molded article. Therefore, under the present circumstances, it is necessary to incorporate a step of removing the glue, and a step of separately treating the removed glue is also required. In addition, there is a problem that the inside of the concrete molded product may become fragile even if the slag is removed. Therefore, it is required to reduce the generation amount of slag as much as possible.

  Furthermore, in addition to reducing the amount of generation of Noro itself, it is also required to reduce the volume of the active ingredient contained in Noro by reducing the cement component contained in Noro.

  In addition, since centrifugal molded concrete is molded by its strong centrifugal force, it does not require a cement dispersant as much as ordinary fresh concrete, but the mixing performance when mixing concrete is improved, the cement surface gets wet, cement Cement dispersants are generally added as well for the purpose of improving the strength of the steel, reducing the amount of sludge generated, etc., and also for shortening the centrifugation time. As a dispersing agent added to centrifugally-formed concrete, what has a naphthalene and formalin condensate as a main component is mentioned, for example.

  With respect to centrifugally-formed concrete to which a cement dispersant may be added, various methods for removing slag and methods for reducing the amount of generated starch have been proposed. For example, low speed, medium speed, and high speed centrifugal force are continuously applied to complete centrifugal force molding, and then the rotational speed is set to low speed or lower, and then rotated for 1 minute or more with centrifugal force 5 G lower than high speed. A method of reducing the amount of generation of starch by centrifugal force molding again (Patent Document 1), applying a substance (such as clay mineral or water absorbing polymer) having water absorbency to concrete in advance (Patent Document 2), predetermined It has been proposed to reduce the amount of sludge generated using concrete in which a dispersant for hydraulic powder containing a polycarboxylic acid-based copolymer having a structure is mixed with cement or the like (Patent Document 3).

  However, in the above-described conventional techniques, there are problems such as that the manufacturing process must be changed, the manufacturing process of the concrete molded product becomes complicated, and the cost is increased by adding an extra additive. In the case of a dispersant containing a polycarboxylic acid copolymer as a main component, there is room for improvement in reducing the generation of starch and reducing the amount of cement contained in starch.

  Furthermore, in centrifugal forming of concrete, relatively hard-kneaded concrete mixed with a mixer or the like is often transported to a form by a belt conveyor or the like, and the concrete being transported is integrated without causing separation. Need to be Since the separation of concrete reduces the workability in production, centrifugal molded concrete is required to have a characteristic (hereinafter sometimes referred to as “integral deformation”) that is difficult to separate while having a certain degree of deformability. Be

JP 10-217228 A Unexamined-Japanese-Patent No. 5-105496 JP, 2017-001897, A

  In view of the above circumstances, the present invention is capable of reducing the amount of cement contained in gullets and reducing the volume of the active ingredient contained in grit, in the concrete molded product produced by centrifugally molding concrete, to the inner part of the concrete. Admixture for centrifugally-formed concrete, which can suppress the strength reduction of the inner part of a concrete molded product by leaving cement portion, and can reduce the time required for centrifugal molding, and further, can obtain integral deformation of concrete The purpose is to provide a cement composition.

  The present invention reduces the amount of cement in grit and reduces the time required for centrifugal forming by applying an admixture containing a polycondensate having a specific structural unit to centrifugally formed concrete, and integrally deforming the concrete. I found that sex was obtained.

・・・（１）
（式中、Ｒ^９は水素又はメチル基、Ｒ^１０、Ｒ^１１、Ｒ^１２は、水素、炭素数１〜６の脂肪族炭化水素基又はメチル基で置換されていてもよいフェニル基であり、Ｎは、水素、ナトリウム、カリウム、カルシウム、マグネシウム、アンモニウム又は有機基で置換されたアンモニウムであり、ａは、１/２又は１である。）で表される、スルホ基含有（メタ）アクリル酸誘導体であるモノマー由来の構成単位を有する水溶性高分子を含む、［３］に記載の混和剤。
［５］［１］乃至［４］のいずれか１つに記載の混和剤と、硬化促進剤としてＣ−Ｓ−Ｈ系微粒子を含む、遠心成形コンクリート用混和剤含有組成物。
［６］［１］乃至［４］のいずれか１つに記載の混和剤を含むセメント組成物。 That is, the gist configuration of the present invention is as follows.
[1] A polycondensate having at least one structural unit (I), at least one structural unit (II), and at least one structural unit (III),
The structural unit (I) is an aromatic moiety having a polyether side chain having an alkylene glycol unit, provided that the number of ethylene glycol units in the side chain is 9 to 41, and contains an ethylene glycol unit The fraction is more than 80 mol% with respect to all the alkylene glycol units in the polyether side chain,
The structural unit (II) is an aromatic moiety having at least one phosphate group and / or a salt thereof, provided that the molar ratio of structural unit (I) to structural unit (II) is 0 .3-4,
The structural unit (III) is at least one methylene unit (—CH ₂ —), and the methylene unit is bonded to two aromatic structural units, the structural unit (I) and the structural unit (II) Wherein said aromatic structural units are, independently of one another, identical or different, and
The admixture for centrifugally-formed concrete whose mass mean molecular weights Mw of the polycondensate containing said structural unit (I), (II) and (III) are the ranges of 3,000-50,000.
[2] The polycondensate further has at least one structural unit (IV),
The structural unit (IV) is represented by an aromatic structural unit different from the structural unit (I) and the structural unit (II),
The methylene unit is bonded to the three aromatic structural units of the structural unit (I), the structural unit (II) and the structural unit (IV), wherein the aromatic structural units are independent of each other Identical or different, and
The mixing according to [1], wherein the weight average molecular weight Mw of the polycondensate containing the structural units (I), (II), (III) and (IV) is in the range of 3,000 to 50,000. Agent.
[3] The admixture according to [1] or [2], further comprising a thickener.
[4] The thickening agent is represented by the following general formula (1)

... (1)
(Wherein, R ⁹ is hydrogen or a methyl group, R ¹⁰ , R ¹¹ and R ¹² are hydrogen, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or a phenyl group which may be substituted with a methyl group, N is a hydrogen, sodium, potassium, calcium, magnesium, ammonium or ammonium substituted with an organic group, and a is 1/2 or 1), a sulfo group-containing (meth) acrylic acid The admixture according to [3], comprising a water-soluble polymer having a structural unit derived from a monomer that is a derivative.
[5] An admixture-containing composition for a centrifugally-formed concrete, comprising the admixture according to any one of [1] to [4], and C-S-H-based fine particles as a curing accelerator.
[6] A cement composition comprising the admixture according to any one of [1] to [4].

  By using the admixture of the present invention for centrifugally-formed concrete, it is possible to reduce the amount of cement generated in the cement and to reduce the volume of the active ingredient contained in cement in the concrete molded product, and the cement component in the inner part of the concrete Can be left to suppress the reduction in strength of the inner part of the concrete molded article. In addition, the admixture of the present invention reduces the time required for centrifugal forming, and further, the integral deformability of concrete is obtained. In addition, when using the admixture of the present invention for centrifugally-formed concrete, there is no need to add extra additives without requiring special manufacturing processes and equipment, so the production efficiency is improved and the cost and the environmental load are reduced. can do.

  Hereinafter, embodiments of the present invention will be described in detail. In the present specification, a numerical range represented using “to” means a range including numerical values described before and after “to” as the lower limit value and the upper limit value.

[Admixture]
The admixture according to the present invention is an additive for centrifugally-formed concrete and is a polycondensation having at least one structural unit (I), at least one structural unit (II) and at least one structural unit (III). Contains things.
Structural unit (I) is an aromatic moiety having a polyether side chain having an alkylene glycol unit, provided that the number of ethylene glycol units in the polyether side chain is 9 to 41, and The content is more than 80 mol%, relative to all alkylene glycol units in the polyether side chain,
Structural unit (II) is an aromatic moiety having at least one phosphate group and / or a salt thereof, provided that the molar ratio of structural unit (I) to structural unit (II) is 0. 0. 3-4,
Structural unit (III) is at least one methylene unit (-CH _2- ), and the methylene unit is bonded to two aromatic structural units Y of the structural unit (I) and the structural unit (II) Wherein the aromatic structural units Y are, independently of one another, identical or different and
The mass average molecular weight Mw of the polycondensate containing structural units (I), (II) and (III) is in the range of 3,000 to 50,000.
By using such an admixture in a centrifugally-formed concrete, it is possible to reduce the amount of cement in the gauze and reduce the volume of the active ingredient contained in the grate, leaving the cement in the inner part of the concrete. As a result, the strength reduction of the inner part of the concrete molded product can be suppressed, and the time required for centrifugal molding can be reduced, and further, the integral deformability of concrete can be obtained.

<Structural unit (I)>
Structural unit (I) has proven to be advantageous to have a minimum polyether side chain length in order to obtain a reasonable dispersing action in cement-binder systems, in particular in centrifugally-formed concrete. Very short chains are not preferred economically. This is because the dispersibility of the admixture is low and the feed amount required to obtain the dispersing action increases, while the viscosity increases if the polyether side chain of the polycondensate is too long. The rheological properties of the concrete made with such admixtures deteriorate. The content of ethylene glycol units in the polyether side chain is preferably more than 80 mol% with respect to all the alkylene glycol units in the polyether side chain, in order to make the polycondensate product sufficiently soluble. More preferably, it is more than 85 mol%, more preferably more than 90 mol%, and particularly preferably more than 95 mol%.

  The aromatic moiety in structural unit (I) has one or more polyether side chains, preferably one polyether side chain. The structural units (I) are, independently of one another, identical or different. Thus, one or more structural units (I) may be present in the polycondensate. The structural units (I) may be the same or different, for example, in terms of the type of polyether side chain and the type of aromatic structure.

  The structural units (I) are derived from the respective aromatic monomers, which have polyether side chains containing alkylene glycol units. The side chain length of the aromatic monomer and the content of ethylene glycol in the side chain correspond to those of the above structural unit (I). The aromatic monomer is incorporated into the polycondensate by a polycondensation reaction. Specifically, it is incorporated into the polycondensate by the formaldehyde of the monomer and the aromatic monomer which becomes the structural unit (I). In particular, structural unit (I) is such that there are no two hydrogen atoms (which form water with one oxygen atom from formaldehyde) which are extracted from the monomers during the polycondensation reaction. , Different from the derived aromatic monomer.

The aromatic moiety in the structural unit (I) is preferably a substituted or unsubstituted aromatic moiety having a polyether side chain according to the present invention, which may be either a benzene ring or a naphthalene ring Good. One or more polyether side chains, preferably one or two polyether side chains, particularly preferably one polyether side chain, can be present in structural unit (I). The above "substituted aromatic moiety" preferably means any substituent other than polyether side chains or polyether side chains according to the present invention. The substituent is preferably a C ₁ -C ₁₀ alkyl group, particularly preferably a methyl group. The aromatic moiety preferably has 5 to 10 carbon atoms in the aromatic structure, more preferably 5 to 6 carbon atoms in the aromatic structure, particularly preferably 6 carbon atoms in the aromatic structure , Benzene or substituted derivatives of benzene. The aromatic moiety in the structural unit (I) may be an atom different from carbon, for example, a heterocyclic aromatic structure containing oxygen (in furfuryl alcohol), but an atom in the aromatic ring structure may be And carbon atoms are preferred.

  The number of ethylene glycol units in the polyether side chain of the structural unit (I) is 9 to 41, preferably 9 to 35, more preferably 12 to 23. The relatively short polyether side chain length imparts rheological properties to concrete made with the admixture for centrifugally-formed concrete of the present invention containing a polycondensate having structural unit (I), and particularly low plastic viscosity is obtained Be On the other hand, when the polyether side chain length is too short, the dispersing action of the admixture for centrifugally-formed concrete decreases, and the supply amount increases in order to obtain a certain level of workability (for example, slump in concrete test).

  The structural unit (I) has a relatively long hydrophilic polyether side chain, which causes steric repulsion between polycondensates adsorbed on the surface of cement particles, resulting in dispersion action. It can be improved.

  The aromatic monomer derived from the structural unit (I) is not particularly limited as long as it can constitute the structural unit (I), and for example, an ethoxylated derivative of an aromatic alcohol or an amine is preferable, and phenol, cresol More preferred are resorcinol, catechol, hydroquinone, naphthol, furfuryl alcohol or ethoxylated derivatives of aniline, with ethoxylated phenol being particularly preferred. The resorcinol, catechol and hydroquinone may have one or two polyether side chains, preferably two polyether side chains. In each case, less than 20 mol% of alkylene glycol units are contained, said alkylene glycol units being not ethylene glycol units.

（式（Ｉａ）中、
Ａは、同一であるか、又は異なり、炭素原子を５〜１０個有する、置換若しくは非置換の芳香族又は複素環式芳香族化合物によって表され、
Ｂは、同一であるか、又は異なり、Ｎ、ＮＨ、又はＯであり、その際、ＢがＮであれば、ｎは２であり、ＢがＮＨ又はＯであれば、ｎは１であり、
Ｒ¹及びＲ²は、相互に独立して、同一であるか又は異なり、分枝鎖状若しくは直鎖状のＣ₁〜Ｃ₁₀アルキル基、Ｃ₅〜Ｃ₈シクロアルキル基、アリール基、ヘテロアリール基又はＨであり、ただし、ポリエーテル側鎖におけるエチレングリコール単位（Ｒ¹及びＲ²がＨである）の数は、９〜４１であり、エチレングリコール単位の含分は、ポリエーテル側鎖中の全てのアルキレングリコールに対して８０ｍｏｌ％超であり、
ａは、同一であるか、又は異なり、１２〜５０の整数であり、かつ
Ｘは、同一であるか、又は異なり、直鎖状若しくは分枝鎖状のＣ₁〜Ｃ₁₀アルキル基、Ｃ₅〜Ｃ₈シクロアルキル基、アリール基、ヘテロアリール基、又はＨである。）によって表される。上記式（Ｉａ）において、基「Ａ」が後述する構造単位（ＩＩＩ）のメチレン単位と結合することより、本発明における遠心成形コンクリート用混和剤の主成分となる重縮合物が形成される。 The structural unit (I) preferably has the following general formula (Ia):

(In formula (Ia),
A is the same or different and is represented by a substituted or unsubstituted aromatic or heteroaromatic compound having 5 to 10 carbon atoms,
B is the same or different and is N, NH or O, in which case if B is N then n is 2 and if B is NH or O then n is 1 ,
R ¹ and R ² are, independently of one another, identical or different, branched or linear C _{1 to} C ₁₀ alkyl group, C _{5 to} C ₈ cycloalkyl group, aryl group, hetero Aryl group or H, provided that the number of ethylene glycol units in the polyether side chain (R ¹ and R ² are H) is 9 to 41, and the proportion of ethylene glycol units is the polyether side chain More than 80 mol%, relative to all alkylene glycols in
a is the same or different, is an integer of 12 to 50, and X is the same or different, and a linear or branched C _{1 to} C ₁₀ alkyl group, C ₅ -C ₈ cycloalkyl group, an aryl group, heteroaryl group, or H. Represented by). In the above-mentioned formula (Ia), a polycondensate which is a main component of the admixture for centrifugally-formed concrete in the present invention is formed by bonding the group "A" to a methylene unit of the structural unit (III) described later.

  In formula (Ia), A preferably has 5 to 10 carbon atoms in an aromatic structure, more preferably 5 to 6 carbon atoms, and particularly preferably 6 carbon atoms in an aromatic structure. And substituted derivatives of benzene or benzene.

  In formula (Ia), B is preferably O (oxygen).

In formula (Ia), R ¹ and R ² are preferably H, methyl, ethyl or phenyl, more preferably H or methyl, and particularly preferably H.

  In formula (Ia), a is preferably an integer of 9 to 35.

  In formula (Ia), X is preferably H.

  The structural unit (I) is preferably derived from an alkoxylated aromatic alcohol monomer having a hydroxy group at the end of the polyether side chain, and in particular, a polycondensate of phenyl polyalkylene glycol preferable. Phenyl polyalkylene glycols can be obtained relatively easily and inexpensively, and furthermore, the reactivity of aromatic compounds is also relatively good.

The structural unit (I) preferably has the structure of a phenylpolyalkylene glycol represented by the following general formula (V):
^{_{- [C 6 H 3 -O- (}} Z 1 O) p -H] - (V)

In formula (V), p is an integer of 9 to 41, preferably an integer of 9 to 35, more preferably an integer of 12 to 23, and Z ¹ is 2 to 5 carbon atoms, preferably 2 to 2 Alkylene having 3 carbon atoms, provided that the proportion of ethylene glycol units (Z ¹ = ethylene) is 80 mol% relative to all alkylene glycol units in the polyether side chain (Z ¹ O) _n More preferably, it is more than 85 mol%, more preferably more than 90 mol%, particularly preferably more than 95 mol%. In Formula (V) above, the aromatic structural moiety of “C ₆ H ₃ ” is bonded to a methylene unit of Structural Unit (III) described later.

The substitution pattern in the aromatic benzene unit (C ₆ H ₃ in the above formula (V)) is the position (1 position) of the oxygen atom bonded to the benzene ring by the activation action (electron donating action) of the oxygen atom bonded to the benzene ring. Are mainly ortho substitution position (2 position) and para substitution position (4 position).

<Structural unit (II)>
The structural unit (II) brings an anionic group to the polycondensate (from phosphoric acid ester to its acid or salt form), which is the positive charge present on the surface of cement particles in the aqueous cement dispersion. Interfere with and are strongly alkaline. Due to electrostatic attraction, the polycondensate adsorbs to the surface of the cement particles and the cement particles are dispersed. Here, the term "phosphate" preferably includes phosphate monoester (PO (OH) ₂ (OR) ₁ ), phosphate diester (PO (OH) (OR) ₂ ), and / or phosphorus. A mixture of acid triesters (PO (OR) ₃ ) is included. The group R in the phosphoric acid ester is an alcohol having no OH group after the ester reaction, which reacts to form an ester with phosphoric acid. The group R preferably has an aromatic moiety. Phosphoric acid monoesters are usually the main products of the phosphorylation reaction.

  The term "phosphorylated monomer" refers to the reaction product of an aromatic alcohol with phosphoric acid, polyphosphoric acid or phosphorous oxide, and the reaction of an aromatic alcohol with a mixture of phosphoric acid, polyphosphoric acid and phosphorous oxide The product is included.

  The proportion of phosphoric monoesters is preferably more than 50% by weight, based on the sum of all phosphoric esters. The content of structural units (II) derived from phosphoric monoesters is preferably more than 50% by weight, based on the sum of all structural units (II).

  In the structural unit (II), the aromatic moiety preferably contains one phosphoric ester group and / or a salt thereof. This means that the use of aromatic monoalcohols is preferred. The structural unit (II) may have more than one and preferably two phosphate ester groups and / or salts thereof. In this case, at least one aromatic dialcohol or aromatic polyalcohol is used. The structural units (II) are, independently of one another, identical or different. This means that one or more of the structural units (II) can be present in the polycondensate.

  The structural unit (II) in the polycondensate is an aromatic moiety having at least one phosphate group and / or a salt thereof, and the molar ratio of the structural unit (I) to the structural unit (II) is 0. 30 to 4.0, preferably 0.40 to 3.5, more preferably 0.45 to 3.0, and particularly preferably 0.45 to 2.5. By being in the above molar ratio range, the polycondensate has more sufficient initial dispersibility (relatively high content of the structural unit (II)) and more sufficient slump retention characteristics (structural unit) in the centrifugally-formed concrete The relatively high content of (I) can be achieved.

  Similar to structural unit (I) above, structural unit (II) also differs from the derived aromatic monomers in that there are no two hydrogen atoms withdrawn from the monomer during the polycondensation reaction.

  The aromatic moiety in the structural unit (II) is preferably a substituted or unsubstituted aromatic moiety having at least one phosphate ester group and / or a salt thereof, and the aromatic is a benzene ring even if it is a benzene ring It may be a ring. At least one phosphate group and / or a salt thereof being present in the structural unit (II), preferably one or two phosphate groups and / or a salt thereof being present, particularly preferably One phosphate ester group and / or a salt thereof may be present. The aromatic moiety of structural unit (II) preferably has 5 to 10 carbon atoms, preferably 5 to 6 carbon atoms in the aromatic structure, and particularly preferably the aromatic structural unit is carbon It is a substituted benzene or benzene having 6 atoms. The aromatic moiety in the structural unit (II) may be a heteroaromatic structure containing an atom different from carbon, such as oxygen (in furfuryl alcohol), but the atom in the aromatic ring structure is carbon It is preferably an atom.

  The structural unit (II) is preferably derived from an aromatic alcohol monomer. The aromatic alcohol monomer is alkoxylated in the first step, and the obtained alkoxylated aromatic alcohol monomer having a hydroxyl group at the end of the polyether side chain is phosphorylated in the second step, Form a phosphate ester group.

  The structural units (II) derived from the respective phosphorylated aromatic alcohol monomers are different from those described above due to the abstraction of two hydrogen atoms from each monomer. The aromatic monomer derived from the structural unit (II) is not particularly limited as long as it can constitute the structural unit (II). For example, a phosphorylated product of an aromatic alcohol or a phosphorylated product of hydroquinone is preferable Phenoxyethanol phosphate (aromatic alcohol: phenoxyethanol), phenoxy diglycol phosphate (aromatic alcohol: phenoxy diglycol), (methoxy phenoxy) ethanol phosphate (aromatic alcohol: (methoxy phenoxy) ethanol), methyl phenoxy ethanol phosphate (aromatic alcohol) : Methyl phenoxy ethanol), nonyl phenol phosphate (aromatic alcohol; nonyl phenol), bis (β-hydroxyethyl) hydroquinone ether phosphate (hydro Non: bis (β- hydroxyethyl) hydroquinone ether), bis (β- hydroxyethyl) hydroquinone ether diphosphate (hydroquinone: bis (β- hydroxyethyl) hydroquinone ether) is more preferable, phenoxy ethanol phosphate, phenoxy diglycol phosphate, bis More preferred is (.beta.-hydroxyethyl) hydroquinone ether diphosphate, with phenoxyethanol phosphate being particularly preferred. It is also possible to use mixtures of the above mentioned monomers from which the structural unit (II) is derived.

Usually, the main product (monoester of phosphoric acid and one equivalent of aromatic alcohol: PO.sub. (OH) during phosphorylation reaction (e.g. reaction of the above aromatic alcohol containing hydroquinone with phosphoric acid) It should be noted that, besides ₂ (OR) ₁ )), by-products are also formed. The by-products are, in particular, a diester of phosphoric acid and 2 equivalents of aromatic alcohol (PO (OH) (OR) ₂ ) or a triester of phosphoric acid and 3 equivalents of aromatic alcohol (PO (OR) ₃ ). The formation of triesters is not usually produced as temperatures above 150 ° C. are required. Here, the group R in the phosphoric acid ester is an aromatic alcohol structure having no OH group after the ester reaction. Unreacted alcohol may be present to some extent in the reaction mixture. The proportion is usually less than 35% by weight, preferably less than 5% by weight, of the aromatic alcohol used. The main product (monoester) after the phosphorylation reaction is usually present in the reaction mixture at a level of more than 50% by weight, preferably more than 65% by weight, based on the aromatic alcohol used.

（式（ＩＩａ）中、
Ｄは、同一であるか、又は異なり、炭素原子を５〜１０個有する、置換若しくは非置換の芳香族又は複素環式芳香族化合物によって表され、
Ｅは、同一であるか、又は異なり、Ｎ、ＮＨ、又はＯであり、ＥがＮであれば、ｍは２であり、ＥがＮＨ又はＯであれば、ｍは１であり、
Ｒ³及びＲ⁴は、相互に独立して、同一であるか、又は異なり、直鎖状若しくは分枝鎖状のＣ₁〜Ｃ₁₀アルキル基、Ｃ₅〜Ｃ₈シクロアルキル基、アリール基、ヘテロアリール基又はＨであり、
ｂは、同一であるか、又は異なり、０〜１０の整数であり、かつ
Ｍａは、相互に独立して、同一であるか、又は異なり、Ｈ又はカチオン等価物である）で表される。上記式（ＩＩａ）において、基「Ｄ」が後述する構造単位（ＩＩＩ）のメチレン単位と結合することより、本発明における混和剤の主成分となる重縮合物が形成される。 The structural unit (II) preferably has the following general formula (IIa):

(In the formula (IIa),
D is the same or different and is represented by a substituted or unsubstituted aromatic or heteroaromatic compound having 5 to 10 carbon atoms,
E is the same or different and is N, NH or O, and when E is N, m is 2 and when E is NH or O, m is 1.
R ³ and R ⁴ are, independently of one another, identical or different, and linear or branched C _{1 to} C ₁₀ alkyl group, C _{5 to} C ₈ cycloalkyl group, aryl group, Heteroaryl or H,
b is the same or different, is an integer of 0 to 10, and Ma is mutually independently, the same or different, and is represented by H or a cation equivalent. In the above formula (IIa), a polycondensate which is a main component of the admixture in the present invention is formed by bonding the group "D" to a methylene unit of the structural unit (III) described later.

  In formula (IIa), D preferably has 5 to 10 carbon atoms in the aromatic structure, more preferably 5 to 6 carbon atoms in the aromatic structure, and particularly preferably in the aromatic structure It is a substituted benzene or benzene having 6 carbon atoms.

  In formula (IIa), E is preferably O (oxygen).

In formula (IIa), R ³ and R ⁴ independently of one another are preferably H, methyl, ethyl or phenyl, more preferably H or methyl, still more preferably H, particularly preferably And R ³ and R ⁴ are both H.

  In formula (IIa), b is preferably an integer of 1 to 5, more preferably an integer of 1 to 2, particularly preferably 1.

The phosphoric acid ester represented by the formula (IIa) may be an acid having two acidic protons (Ma = H). Phosphoric esters can also be present in deprotonated form, in which case the protons are replaced by cation equivalents. The phosphate ester may be partially deprotonated. The term "cation equivalent" refers to any metal cation or ammonium cation (which can replace a proton) which may be substituted, but the molecule is electrically neutral. Ma is preferably NH ₄ , an alkali metal or a half alkaline earth metal.

  The group A of the structural unit (Ia) and the group D of the structural unit (IIa) are, for example, independently of each other, phenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-methoxyphenyl It is preferably 3-methoxyphenyl or 4-methoxyphenyl, more preferably phenyl. A plurality of structural units (Ia) having different types of groups A may be present in the polycondensate, and a plurality of structural units (IIa) having different types of groups D may also be present in the polycondensates Good. The groups B and E are preferably, independently of one another, O (oxygen).

The structural unit (II) is preferably an alkoxylated phenol phosphate as represented by the following general formula (VI), or an alkoxylated as represented by the following general formula (VII) Having the structure of hydroquinone phosphate ester:
^{_{- [C 6 H 3 -O- (}} Z 2 O) q -PO 3 M 2] - (VI)
_{- [[M 2 O 3 P-} (Z 3 O) r] -O-C 6 H 2 -O - [(Z 4 O) s -PO 3 M 2]] - (VII)

In any of the formulas (VI) and (VII), q, r and s are an integer of 1 to 5, preferably an integer of 1 to 2, particularly preferably 1, Z ² , Z ³ and Z ⁴ are And, independently of each other, alkylene having 2 to 5, preferably 2 to 3 carbon atoms, more preferably ethylene. M is, independently of one another, identical or different, H or a cation equivalent. The aromatic structural moiety of “C ₆ H ₃ ” in the above formula (VI) and the aromatic structural moiety of “C ₆ H ₂ ” in the above formula (VII) are methylene of structural unit (III) described later, respectively. Combined into a unit.

The esters of the general formulas (VI) and (VII) may be acids with two acidic protons (M = H). The ester may also be present in deprotonated form, in which case the protons are replaced by cation equivalents. The ester may be partially deprotonated. The term cation equivalent is as described above and M is preferably NH ₄ , an alkali metal, or a 1/2 alkaline earth metal. Thus, for example, in the case of an alkaline earth metal having two positive charges, there must be a factor of 1/2 to guarantee neutrality (1/2 alkali metal), for example a metal When component "M" is Al ³⁺ , 1⁄3 Al is the cation equivalent. In addition, for example, a mixed cation equivalent having two or more types of metal cations may be used.

  Such alkoxylated phenol phosphates or alkoxylated hydroquinone phosphates can be obtained relatively easily and inexpensively, and furthermore, the reactivity of aromatic compounds in the polycondensation reaction is also compared Good.

<Structural unit (III)>
Structural unit (III) is at least one methylene unit (—CH ₂ —), and the methylene unit is bonded to two aromatic structural units, structural unit (I) and structural unit (II) The aromatic structural units are, independently of one another, identical or different and correspond to the above-mentioned aromatic moieties in structural unit (I) and structural unit (II). The methylene units are introduced by the reaction of formaldehyde while forming water during the polycondensation, preferably more than one methylene unit is contained in the polycondensate.

<Structural unit (IV)>
The polycondensate may further have at least one structural unit (IV). Structural unit (IV) is an aromatic structural unit of a polycondensate different from structural unit (I) and structural unit (II), and may be any aromatic structural unit. Further, when the structural unit (IV) is contained, the methylene unit in the structural unit (III) is bonded to three aromatic structural units of the structural unit (I), the structural unit (II) and the structural unit (IV) The aromatic structural units in structural unit (IV) are, independently of one another, identical or different. This means that one or more structural units (IV) can be present in the polycondensate.

  The structural unit (IV) can be derived, for example, from any aromatic monomer capable of reacting with formaldehyde in the polycondensation reaction (two hydrogen atoms are withdrawn from each aromatic monomer). Examples of monomers from which the structural unit (IV) is derived include phenoxy alcohol, phenol, naphthol, aniline, benzene-1,2-diol, benzene-1,2,3-triol, 2-hydroxybenzoic acid, 2,3- Dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, phthalic acid, 3-hydroxyphthalic acid, 1,2-dihydroxynaphthalene, and 2,3-dihydroxynaphthalene Not limited to these.

  The structural unit (IV) may also be a structural unit similar to the structural unit (I), which differs from the structural unit (I) in that only the number of ethylene glycol units in the side chain differs. As such structural unit (IV), preferably, it is an aromatic moiety having a polyether side chain having an alkylene glycol unit, provided that the number of ethylene glycol units in the polyether side chain is 42 to 120, And the content of ethylene glycol units is a structural unit which is more than 80 mol% with respect to all the alkylene glycol units in the polyether side chain.

<Polycondensate>
The above-mentioned polycondensate contained in the admixture for centrifugally-formed concrete of the present invention is a main component of the admixture for centrifugally-formed concrete, and is a polycondensate containing structural units (I), (II) and (III), And the mass mean molecular weight Mw of the polycondensate containing structural unit (I), (II), (III), and (IV) is the range of 3,000-50,000.

  The value of the molar ratio of ethylene glycol units from structural unit (I) to phosphoric acid ester units from structural unit (II) is preferably 11 to 40/1, and more preferably 12 to 35/1. , 13 to 30/1 are particularly preferred. To identify this molar ratio, the sum of all ethylene glycol units from structural unit (I) is calculated, also taking into account the presence of different types of structural units (I).

  The molar ratio of ethylene glycol units from structural unit (I) to phosphoric acid ester units from structural unit (II) is calculated to be at least 9 and at most 41 in structural unit (I) Alkylene glycol is combined with the molar ratio value of 0.30 to 4.0 of the structural unit (I) to the structural unit (II), and the minimum value is 9/8 (structural unit (I) / structural unit Consider the possibility that a short side chain of 9EO with a molar ratio value of (II) of 4.0, as well as two phosphate groups may be present in the structural unit (II)). On the other hand, in combination with 0.30 which is the lower limit value of the molar ratio of structural unit (I) / structural unit (II), a long side chain of 41 EO and a phosphate ester present in structural unit (II) The maximum value is obtained as 136.7 (41 / 0.3). When the molar ratio of ethylene glycol units from structural unit (I) to phosphoric acid ester units from structural unit (II) is lower than the lower limit (9/8), the phosphoric acid ester group is excessive, so for centrifugal molding Slump retention in concrete specimens is worse. On the other hand, if this molar ratio is larger than the upper limit value (136.7), the adsorptivity to cement particles is too weak, so that the water reduction characteristics (initial water reduction rate in the concrete sample for centrifugal forming) are not very good. Thus, the range of the molar ratio of ethylene glycol units from structural unit (I) to phosphoric acid ester units from structural unit (II) is in the range of 9/8 to 136.7, for centrifugal molding In concrete specimens, an appropriate balance of the two characteristics of slump retention and water reduction rate can be obtained, and both a good water reduction rate and a good slump retention can be obtained. Moreover, the viscosity of the concrete for centrifugal molding can also be made low.

  The molar ratio of the total of structural units (I) and (II) to structural unit (III) is preferably 0.8 / 1 to 1 / 0.8, more preferably 0.9 / 1 to 1 / 0.9. , Particularly preferably 1/1.

  When structural unit (IV) is further contained in the polycondensate, the molar ratio of the sum of structural unit (I) and structural unit (II) to structural unit (IV) is preferably more than 1/1, More preferably, it is more than 3/1, more preferably more than 5/1.

  Most preferred are polycondensates in which structural unit (IV) is an aromatic moiety having a polyether side chain containing alkylene glycol units, provided that the number of ethylene glycol units in the polyether side chain of structural unit (IV) Is 42 to 50, and the content of ethylene glycol units is more than 80 mol% with respect to all alkylene glycol units in the polyether side chain of the structural unit (IV).

  The mass average molecular weight of the polycondensate is 3,000 to 50,000 g / mol, preferably 5,000 g / mol to 25,000 g / mol, more preferably 8,000 g / mol to 22,000 g / mol , Particularly preferably 10,000 g / mol to 19,000 g / mol.

The mass average molecular weight Mw of the polycondensate is the mass average molecular weight of the polycondensate specified by GPC. The combination of columns is OH-Pak SB-G, OH-Pak SB 804 HQ, and OH-Pak SB 802.5 HQ (manufactured by Shodex, Japan), and the eluent is an 80% by volume aqueous solution of HCO ₂ NH ₄ (0.05 mol / l) and 20% by volume of acetonitrile, others, injection volume: 100 μl, flow rate: 0.5 ml / min. Molecular weight calibration is performed with poly (styrene sulfonate) standards for UV detectors and poly (ethylene oxide) standards for RI detectors. Both standards can be purchased from PSS Polymer Standards Service in Germany. UV detection is used at 254 nm to determine the molecular weight of the polymer. UV detectors do not sense inorganic impurities, so they can only sense aromatic compounds.

<Thickener>
The admixture for centrifugally-formed concrete of the present invention may further contain a thickener as a thickening component, in addition to the above-mentioned polycondensate. The thickener can adjust the flowability, viscosity, resistance to separation of materials, interpassability of centrifugally formed concrete, and contributes to not changing these characteristics over time. Examples of the thickener include compounds having a thickening effect such as (co) polymers, natural polysaccharides, polysaccharide derivatives and the like. The weight average molecular weight Mw of the (co) polymer is preferably more than 500,000, and more preferably more than 1,000,000.

  The (co) polymer is preferably a water-soluble polymer represented by the following formula (1) and containing a structural unit derived from a monomer which is a sulfo group-containing (meth) acrylic acid derivative.

・・・（１）
（式中、Ｒ^９は水素又はメチル基を表し、Ｒ^１０、Ｒ^１１、及びＲ^１２はそれぞれ独立して水素、炭素数１〜６の炭化水素基、又は、メチル基で置換されていてもよいフェニル基であり、Ｎは、水素、ナトリウム、カリウム、カルシウム、マグネシウム、アンモニウム又は有機基で置換されたアンモニウムであり、ａは、１/２又は１である。）

... (1)
(Wherein, R ⁹ represents hydrogen or a methyl group, and R ¹⁰ , R ¹¹ and R ¹² are each independently hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, or substituted with a methyl group) A good phenyl group, N is hydrogen, sodium, potassium, calcium, magnesium, ammonium or ammonium substituted with an organic group, a is 1/2 or 1)

  Since the water-soluble polymer containing the structural unit represented by the above (1) is excellent in compatibility with other additives, it is possible to reduce the load on the supply surface of the admixture and the time of addition.

The water-soluble polymer containing the structural unit represented by the above (1) may contain the following structural units (2) to (4) derived from other monomers.
Structural unit (2): Acrylamide, methacrylamide, N-methyl acrylamide, N, N-dimethyl acrylamide, N-ethyl acrylamide, N-cyclohexyl acrylamide, N-benzyl acrylamide, N-methylol acrylamide, N-t-butyl acrylamide A constituent unit derived from
Structural unit (3): tristyrylphenol-polyethylene glycol-1100-methacrylate, behenylpolyethylene glycol-1100-methacrylate, stearyl polyethylene glycol-1100-methacrylate, tristyrylphenol-polyethylene glycol-1100-acrylate, tristyrylphenol-polyethylene glycol -1100-monovinyl ether, behenyl polyethylene glycol-1100-monovinyl ether, stearyl polyethylene glycol-1100-monovinyl ether, tristyrylphenol-polyethylene glycol-1100-vinyloxy-butyl ether, behenyl polyethylene glycol-1100-vinyloxy-butyl ether, tristyrylphenol Polyethylene glycol - block - propylene glycol allyl ether, behenyl polyethylene glycol - block - propylene glycol allyl ether, stearyl polyethylene glycol - block - constituent unit derived from propylene glycol allyl ether,
Structural unit (4): allyl polyethylene glycol- (350-2000), methyl polyethylene glycol- (350-2000) -monovinyl ether, polyethylene glycol- (500-5000) -vinyloxy-butyl ether, polyethylene glycol-block-propylene glycol- Structural units derived from (500 to 5000) -vinyloxy-butyl ether, methyl polyethylene glycol-block-propylene glycol allyl ether.

  As a ratio of structural unit (1)-(4) in the water-soluble polymer containing the structural unit represented by said (1), structural unit (1) 3-96 mol%, structural unit (2) 3-96 mol %, The structural unit (3) 0.01 to 10 mol%, and the structural unit (4) 0.1 to 30 mol%.

Other (co) polymers that can be used as thickeners include, for example, those made from monomers selected from the group consisting of nonionic (meth) acrylamide monomer derivatives and sulfonic acid monomer derivatives. Nonionic (meth) acrylamide monomer derivatives include acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N, N-dimethyl acrylamide, N-ethyl acrylamide, N, N-diethyl acrylamide, N-cyclohexyl Mention may be made of monomers selected from the group consisting of acrylamide, N-benzyl acrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminoethyl acrylamide and N-tert-butyl acrylamide. Examples of sulfonic acid monomer derivatives include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 2-methacrylamido-2-methyl propane sulfonic acid, 2-acrylamido butane sulfonic acid and 2-acrylamido-2,4,4- Mention may be made of monomers selected from the group consisting of trimethylpentanesulfonic acid. The (co) polymer may have a structural unit other than the structural unit derived from the nonionic (meth) acrylamide monomer derivative and the sulfonic acid monomer derivative. As structural units other than structural units derived from nonionic (meth) acrylamide monomer derivatives and sulfonic acid monomer derivatives, for example, esters of (meth) acrylic acid, (meth) acrylic acid and a C ₁ -C ₁₀ -alcohol Mention may be made of structural units derived from monomers such as vinyl acetate, vinyl propionate and styrene. When the (co) polymer contains structural units derived from nonionic (meth) acrylamide monomer derivatives and sulfonic acid monomer derivatives and structural units other than the (co) polymer, nonionic (meth) acrylamide monomers in the (co) polymer The content of the structural unit derived from the derivative and the sulfonic acid monomer derivative is preferably 50 mol% or more, and more preferably 70 mol% or more.

  Moreover, natural polysaccharides can be used as a thickener. Natural polysaccharides include, for example, polysaccharides produced by microorganisms such as welan gum and xanthan, as well as alginates, carrageenan and galactomannan.

  Moreover, as a thickener, a polysaccharide derivative can be used. Examples of polysaccharide derivatives include alkyl celluloses such as methyl cellulose (MC), ethyl cellulose, propyl cellulose and methyl ethyl cellulose, hydroxyalkyl celluloses such as hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC) and hydroxyethyl hydroxypropyl cellulose, methyl hydroxy Mention may be made of alkylhydroxyalkylcelluloses such as ethylcellulose (MHEC), methylhydroxypropylcellulose (MHPC) and propylhydroxypropylcellulose. Preferably, polysaccharide derivatives of methylcellulose (MC), hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC) and ethyl hydroxyethyl cellulose (EHEC) are used. More preferably, they are methyl hydroxyethyl cellulose (MHEC) and methyl hydroxypropyl cellulose (MHPC). It is also preferable to use polysaccharide derivatives of carboxymethylcellulose (CMC). Also, as polysaccharide derivatives, nonionic starch ether derivatives such as hydroxypropyl starch, hydroxyethyl starch and methylhydroxypropyl starch may be used.

  The thickener may be contained as part of the components of the admixture of the present invention, or may be added to concrete separately from the admixture of the present invention. When making it a part of ingredient of the admixture of the present invention, it is limited to the range which does not inhibit the effect of the present invention, and it is preferred to contain 0.1-3 mass% to the admixture of the present invention.

[Admixture-containing composition]
The admixture for a centrifugally-formed concrete of the present invention contains the admixture for a centrifugally-formed concrete and a hardening accelerator. That is, the admixture-containing composition is not intended to be a one-part type state in which the curing accelerator is contained as a part of the components of the above-mentioned admixture, and the curing accelerator is the above-mentioned admixture and May be in the form of a separately added two-component type (separate type). Among these, it is preferable to add a hardening accelerator to concrete separately from the above-mentioned admixture. As such a curing accelerator, a curing accelerator in which C-S-H type nanoparticles are dispersed as C-S-H type fine particles is preferable. A hardening accelerator having dispersed therein C-S-H-based nanoparticles is preferable because the main component is the same as the cement hydrate. The dispersant for dispersing C—S—H-based nanoparticles is not particularly limited, and is, for example, at least one selected from polyalkylene glycol having a functional group at the end, a water-soluble comb polymer, and a polyarylether compound. It is preferably a species.

The calcium silicate hydrate which comprises a C-S-H type | system | group nanoparticle has the following general formula (A)
dCaO · SiO ₂ · eH ₂ O (A)
(In the formula, preferably 0.1 ≦ d ≦ 2, more preferably 0.66 ≦ d ≦ 1.8, and preferably 0.6 ≦ e ≦ 6. Preferably, 1.2 ≦ e ≦ 5.5).

  The particle size of the calcium silicate hydrate is not particularly limited, and is preferably less than 1000 nm, more preferably less than 300 nm, and particularly preferably less than 200 nm. The particle size of calcium silicate hydrate can be measured by analytical ultracentrifugation.

Calcium silicate hydrates include, for example, phosphalite, hirebrandite, zonolite, feline stone, monoclinic tobermorite, 9 Å-tobermorite (riverside stone), 11 Å-tobermorite, 14 Å-tobermorite (prombierite), jennisite And metagennite, calcium chondrite, aphyllite, α-C ₂ SH, dellite, japheite, rosenhaan stone, quillaite stone, and sourneite. In particular, Zonotrite, 9 Å-tobermorite (riverside stone), 11 Å-tobermorite, 14 Å-tobermorite (Prombierite), jenniite, metagenite, aphyrite, and japheite are preferable.

  The curing accelerator may further contain the above-mentioned thickener polymer. The thickener polymer is not particularly limited, and, for example, the above-mentioned various (co) polymers, natural polysaccharides and polysaccharide derivatives are preferable, and the mass average molecular weight Mw is preferably more than 500,000 g / mol, in particular Preferably it is more than 1,000,000 g / mol.

  Such curing accelerators may be used alone or in combination of two or more. Moreover, content of a hardening accelerator is not specifically limited, According to a use condition etc., it can set suitably.

  The additive for centrifugally-formed concrete of the present invention may optionally contain other additives as needed. Other additives include conventionally used AE agents, polysaccharide derivatives, lignin derivatives, drying shrinkage reducing agents, accelerators, foaming agents, antifoaming agents, antirust agents, quick-setting agents, high water solubility Molecular substances and the like can be mentioned. Other additives may be contained as part of the components of the admixture for centrifugally-formed concrete of the present invention, or may be added to concrete separately from the admixture for centrifugally-formed concrete of the present invention. When it is used as a part of the components of the admixture for centrifugally-formed concrete of the present invention, it is limited to a range that does not inhibit the effect of the present invention, and is contained at 1 to 20% by mass Is preferred.

<Cement composition>
The cement composition containing the admixture for centrifugally-formed concrete according to the present invention can use commercially available cement as the cement. Among such cements, it is preferable to use ordinary portland cement and / or early strength portland cement from the viewpoint of versatility and / or early strength.

(Other powder)
Limestone powder, calcium carbonate, silica fume, ground granulated blast furnace slag, fly ash and the like as a powder substituted or partially added to cement contained in a cement composition containing the admixture for centrifugally molded concrete according to the present invention Fine powder admixtures can be added. These powders have a compounding amount of 1 to 100 kg in 1 m ^{3 of} cement composition in order to suppress material separation, maintain appropriate viscosity and high fluidity, and in the range that does not interfere with the effects of the present invention. It is preferable that it is / m ³ .

(Expanding material)
An expansive agent can be added to the cement composition containing the admixture for centrifugally-formed concrete according to the present invention. By the effect of the expansive material, an effect of contraction compensation, crack prevention, and bending strength improvement is imparted. Examples of the expansive agent include a lime-based expansive agent and a calcium sulfoaluminum-based expansive agent, which generate expansive calcium hydroxide and ettringite by hydration reaction, and generate a gas by reaction. Aluminum powder, methyl ethyl ketone peroxide, azodicarbonamide, sodium azodicarboxylate, p-toluenesulfonyl hydrazide, sulfonyl hydrazide compound, azo compound and nitroso compound can be mentioned. Since a strong centrifugal force is applied to the concrete for centrifugal forming, a lime-based expansive material, a calcium sulfoaluminum-based expansive material, and an expansive material obtained by mixing these are preferable. Specific expansive materials marketed include, for example, "Denka CSA # 20" from Denka, "Pacific Expand" from Pacific Cement, and "Sax" from Sumitomo Osaka Cement.

(aggregate)
In cement compositions containing the admixture for centrifugally molded concrete according to the present invention, it is preferable to use natural aggregate. It is preferable to use sea sand, land sand, mountain sand, crushed sand, etc. as fine aggregate, and it is preferable to use mountain gravel, river gravel, sea gravel, crushed stone as coarse aggregate. Centrifugated concrete using these aggregates is likely to obtain the effect of the additive. In addition, the aggregate particle size is preferably aggregate having a suitable particle size distribution from the viewpoint of securing flowability, and the particle size distribution of the aggregate specified in the aggregate of JIS A 5308 Appendix A ready mixed concrete is preferred. It is preferable to have.

<Concrete type>
The admixture for centrifugally-formed concrete of the present invention can be used in any concrete that is formed by centrifugal force. Its application includes hollow concrete moldings such as concrete piles, utility poles, and fume tubes.

<Manufacturing of concrete>
The cement composition containing the admixture for centrifugally-formed concrete according to the present invention can be manufactured by a conventionally known method, and is prepared, for example, by the concrete standard written by the Japan Society of Civil Engineers and the Japan Architectural Institute of Japan. It can manufacture with the well-known installation and well-known method according to the building construction standard specification. Specifically, after mixing the admixture for centrifugally-formed concrete according to the present invention into kneading water in advance, another raw material such as cement, aggregate and the like is charged into a mixer for manufacture, or the centrifugal according to the present invention The method of putting together all the raw materials of the cement composition containing the admixture for shaping | molding concrete, and injecting into a mixer and manufacturing is preferable. Moreover, it is preferable to manufacture the cement composition containing the admixture for centrifugally-formed concrete which concerns on this invention by the unrefined plant according to JISA5308.

  Hereinafter, the admixture for centrifugally-formed concrete of the present invention and a cement composition using the same will be described in detail by way of examples. The present invention is not limited to the examples shown below.

  Concrete is manufactured using the materials shown in Table 1 below under the compounding conditions shown in Table 3 below, and the condition of the concrete is visually observed, and the amount of slump and grate generated, solid fraction, solid content and material age 28 days The concrete was manufactured on the compounding conditions shown in following Table 3 using Experiment 1 which measured the compressive strength in, and the use material shown in following Table 2, and the experiment 2 which measured the formation time of slump and concrete was done.

The materials used in Experiment 1 are shown in Table 1 below, and the materials used in Experiment 2 in Table 2 below.

The blend ratio of the cement composition is shown in Table 3 below.

Preparation of admixture: refer to JP-A-2017-502140 Preparation of thickener: refer to JP-A-2008-505234

Method of mixing: Of the above-mentioned materials used, cement and aggregate are put into "Two-axis forced mixer mixer SD-55 type" manufactured by Pacific Kiko Co., Ltd., air-kneaded for 60 seconds, and once mixing is stopped, water and admixture The mixture was further kneaded for 60 seconds to obtain concrete. In addition, the addition amount of an admixture and a thickener was adjusted with the compounding quantity shown to following Table 4 and following Table 5, and was adjusted to the target slump.

Centrifugal Forming Method In Experiment 2, after measuring the slump of the manufactured concrete, it was transported by a belt conveyor, and 0.60 m ³ of concrete was introduced into a centrifugal forming machine with an inner diameter of 800 mm, a tube thickness of 80 mm and a length of 1200 mm. Thereafter, the forming cylinder was rotated at an acceleration of 5 G for 2 minutes, 11 G for 3 minutes, and 37 G for 6 minutes to apply a centrifugal force to the concrete.

Slump The slump value was measured in accordance with JIS A 1101.

State of Slump The deformation behavior of the slump in the slump test was evaluated by the following three stages by the visual observation of the measurer.
優 れ る Excellent: Integrally deformed ○ Good: Slump slightly broken, but generally deformed as a whole × Separation: Slump broken and deformed

Amount of Noro Generation After completion of centrifugal compaction for a predetermined time, the whole of Noro generated inside the test body was scraped out, collected in a bucket, and its weight was measured. The weight was converted to 1 m ³ of concrete to obtain the amount of generated sludge.

Solid Fraction in Noro 500 g of a portion of Noro obtained as described above was collected, dried at 105 ° C., and the solid fraction in Noro was determined from the residue. In addition, since what was recognized as a fine aggregate exceeding 5 mm was not observed in the grain, it was estimated that the main component of solid content was a cement component.

Solid content in grate The solid content in grate was calculated from the product of the amount of grate generation measured as described above and the solid fraction in grate. In the present example, the solid content in grate means the solid amount of grate generated in 1 m ^{3 of} concrete, and was evaluated in the following two steps.
○ Good: 10 kg / m ³ or less × Defective: 10 kg / m ^{3 or} more

Compressive strength at 28 days of material Based on JIS A 1108, the compressive strength at 28 days of material was measured.

Centrifugation time In Experiment 2, the production conditions of the above-mentioned concrete and the input conditions to the centrifugal molding machine were the same, and the time required for molding was measured as the centrifugal time. Centrifugation time was determined by the visual judgment of the person who had mastered the centrifugal molded concrete to determine the centrifugal molding completion time.

The results of Experiment 1 are shown in Table 4 below.

The results of Experiment 2 are shown in Table 5 below.

  In Experiment 1, from Examples 1 and 2, the concrete using SP1 which is the admixture according to the present invention was in a good state of slump, showed a low solid fraction and solid content in the gauze and showed good results. . Among them, in Example 2 in which a thickener was further added, the solid fraction and solid content in the starch could be further reduced, and furthermore, the amount of the starch produced could be further reduced. In Examples 1 and 2, good compressive strength at 28 days of material age was obtained.

  On the other hand, although the concrete using SP2 which is not the admixture of the present invention was in a slump condition, the solid fraction and solid content in the gauze also increased. Similarly, the concrete using SP3 which is not the admixture of the present invention was good in the solid fraction and solid content in the grate, but the slump collapsed and deformed, and the state of the slump was inferior.

  In Experiment 2, the concrete using SP1 was able to reduce the centrifugal time more than the concrete using SP2.

  By applying the admixture of the present invention to centrifugally-formed concrete, that is, by using it as an admixture for centrifugally-formed concrete, it is possible to give concrete with cohesive integrity and reduce work loss during transportation. Since the solid content in the generated starch can be reduced and the centrifugal time can be shortened, the volume of waste can be reduced and the production efficiency can be improved in the production of centrifugally-formed concrete.

Claims (6)

A polycondensate having at least one structural unit (I), at least one structural unit (II) and at least one structural unit (III),
The structural unit (I) is an aromatic moiety having a polyether side chain having an alkylene glycol unit, provided that the number of ethylene glycol units in the side chain is 9 to 41, and contains an ethylene glycol unit The fraction is more than 80 mol% with respect to all the alkylene glycol units in the polyether side chain,
The structural unit (II) is an aromatic moiety having at least one phosphate group and / or a salt thereof, provided that the molar ratio of structural unit (I) to structural unit (II) is 0 .3-4,
The structural unit (III) is at least one methylene unit (—CH ₂ —), and the methylene unit is bonded to two aromatic structural units, the structural unit (I) and the structural unit (II) Wherein said aromatic structural units are, independently of one another, identical or different, and
The admixture for centrifugally-formed concrete whose mass mean molecular weights Mw of the polycondensate containing said structural unit (I), (II) and (III) are the ranges of 3,000-50,000. The polycondensate further comprises at least one structural unit (IV),
The structural unit (IV) is represented by an aromatic structural unit different from the structural unit (I) and the structural unit (II),
The methylene unit is bonded to the three aromatic structural units of the structural unit (I), the structural unit (II) and the structural unit (IV), wherein the aromatic structural units are independent of each other Identical or different, and
The blend according to claim 1, wherein the weight average molecular weight Mw of the polycondensate containing the structural units (I), (II), (III) and (IV) is in the range of 3,000 to 50,000. Agent.   The admixture according to claim 1, further comprising a thickener. The thickener has the following general formula (1)

... (1)
(Wherein, R ⁹ is hydrogen or a methyl group, R ¹⁰ , R ¹¹ and R ¹² are hydrogen, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or a phenyl group which may be substituted with a methyl group, N is a hydrogen, sodium, potassium, calcium, magnesium, ammonium or ammonium substituted with an organic group, and a is 1/2 or 1), a sulfo group-containing (meth) acrylic acid The admixture according to claim 3, comprising a water-soluble polymer having a structural unit derived from a monomer which is a derivative.   An admixture-containing composition for centrifugally-formed concrete, comprising the admixture according to any one of claims 1 to 4 and C-S-H-based fine particles as a curing accelerator.   A cement composition comprising the admixture according to any one of claims 1 to 4.