JP6695549B2 - Admixture for geopolymer and cured geopolymer - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an admixture for a geopolymer, a geopolymer-forming composition containing the admixture, and a cured geopolymer which is a cured product of the composition. More specifically, it relates to an admixture for a geopolymer, which suppresses drying shrinkage of a blended geopolymer cured product and exhibits a shrinkage reducing effect.

A geopolymer (hereinafter also referred to as GP) proposed by Davidovits of France in 1978 is an active filler (aluminosilicate source) such as metakaolin which is stimulated with an alkaline solution (alkali source: alkali metal silicate, NaOH, etc.). It is an inorganic material that is hardened by curing and can be made into a hardened body without using cement. CO ₂ emissions in the production of cement, to occupy the least 60% of the total CO ₂ emissions during concrete production, the GP becomes unnecessary to use it, compared with ordinary concrete, 80 CO ₂ emissions It can be reduced by about 90% (Non-Patent Document 1), and is attracting attention as a material that can reduce the environmental load.
Since the above-mentioned active filler constituting GP serves as a source of cations necessary for curing GP, it is desirable that it contains a large amount of Si and Al as constituent elements, and if it is a natural product, metakaolin or the like is used. In addition, fly ash (hereinafter, also referred to as FA), blast furnace slag fine powder (hereinafter, also referred to as BFS), municipal waste incineration ash molten slag fine powder, sewage sludge molten slag fine powder, and other waste materials and by-products are also used as active fillers. be able to. Therefore, GP is positioned as an important technology from the viewpoint of waste recycling.
Further, GP is superior in strength development, fire resistance, alkali-aggregate reaction resistance, sulfate resistance, and is capable of fixing heavy metals, as compared with conventional concrete using Portland cement.

  Up to now, many cases have been reported in which FA and BFS are adopted as active fillers for geopolymers. Among the active fillers, GP using FA alone, which has a relatively low content of calcium oxide (CaO), has a long setting and hardening time (for example, at room temperature (in the air), 1 day or more), and is sufficient. Although a long pot life is ensured, strength development is poor (for example, Non-Patent Document 2 and Non-Patent Document 3). On the other hand, GP using BFS, which has a relatively high content of calcium oxide, as an active filler is very excellent in strength development, but the setting time at room temperature is extremely short at about 10 to 40 minutes, and its workability is poor. For this reason, some studies have been reported on the use of BFS mixed with a geopolymer using FA for the purpose of enhancing GP strength development (for example, Non-Patent Document 3 and Non-Patent Document 4).

In addition, a method for adjusting the setting time of the GP composition by using an admixture has been studied with the aim of developing a technique for appropriately and simultaneously controlling the compressive strength and setting time of GP (Patent Document 1). For example, methods of controlling the setting time of GP using sugars, acids, and chelating agents have been proposed.
Furthermore, experimental consideration has been reported on changes in setting time and compressive strength of geopolymer mortar using a fly ash base containing sucrose or citric acid (Non-Patent Document 5). Further, by using potassium hydroxide as the metal hydroxide used in the alkali silica solution and adjusting the concentration of potassium hydroxide and the SiO ₂ / K ₂ O molar ratio of the alkali silica solution, GP using BFS can be used. It has been pointed out that the setting time can be extended (Non-Patent Document 6).

The history of GP research is still short, and for example, the curing reaction of GP is said to proceed by polycondensation of the above-mentioned cation derived from the active filler and the silicic acid compound derived from the alkali silica solution (Patent Document 2). However, there are still many unclear points in the details of the mechanism, such as the setting time and strength changing depending on the active filler used.
And in the current situation, when using an active filler having a relatively high content of calcium oxide, the characteristics of setting and strength are very fast, and from the viewpoint of practical application as a new inorganic material replacing Portland cement, As shown in the above-mentioned literature, it can be said that the GP research is mainly focused on control (compatibility) of compressive strength (strength development) and setting time (workability).
Under such circumstances, in the study by the present inventors, in addition to the above-described viewpoint of strength development and workability, it was noted that the GP shrinkage characteristics are significantly different from those of conventional cement concrete. For example, in GP, as the polycondensation reaction with an aluminosilicate source and an alkali source, which is considered as one mode of the curing reaction, progresses, the water in the alkali silica solution is discharged out of the system, and a large amount is generated in the cured body. Volume change (dry shrinkage) occurs. On the other hand, GP may need to be aged in air because it may cause a decrease in the concentration of alkali source and exudation, but the strain due to dry shrinkage of GP concrete demolded after curing in air (normal temperature) for 7 days ( It was found that the shrinkage strain is much larger than that of conventional cement concrete (about 3 to 4 times), which is an issue that cannot be overlooked when aiming for the practical use of GP. If the dry shrinkage strain is usually large (800 μm / m) or more, cracks may occur in the cured product, but at present, there are very few verification examples and report examples regarding means for suppressing the dry shrinkage of GP. Few.
Based on these various problems, the present invention provides a cured product capable of suppressing drying shrinkage as well as extending the fluidity retention time before curing of the geopolymer and ensuring the strength development of the cured product, which has been a problem so far. It is an object to provide a new additive for geopolymer obtained.

  As a result of studies by the present inventors, a shrinkage-reducing agent comprising one or more oxyalkylene alkyl ether-based compounds having a specific structure and a shrinkage-reducing auxiliary agent comprising one or more aliphatic oxycarboxylic acid-based compounds are combined. As an admixture, and by using this for a geopolymer, it suppresses drying shrinkage, significantly reduces the shrinkage strain in the cured product, and secures workability without impairing strength expression, and further, It has been found that generation of darkening and white sinter on the surface of the cured product can be suppressed and a surface aesthetic effect can be obtained.

That is, the present invention is
The following general formula (1)
-O- (AO) n- (1)
[In the formula, AO represents a divalent alkylene oxide group having 2 to 4 carbon atoms, and n represents an average addition mole number of alkylene oxide and represents 1 to 200. ]
A shrinkage reducing agent for a geopolymer containing an ether compound having a structure represented by:
A mass-weighted average of the hydroxyl value / acid value of the aliphatic oxycarboxylic acid, including a salt of at least one aliphatic oxycarboxylic acid having a hydroxyl value of 250 to 1500 mgKOH / g and an acid value of 250 to 950 mgKOH / g. A shrinkage reducing auxiliary agent for geopolymer having a value of 0.40 or more and less than 5.00,
The shrinkage-reducing aid contains at least one salt of an aliphatic oxycarboxylic acid selected from the group consisting of lactate, malate, and tartrate.
It relates to an admixture for geopolymers.

In the admixture for geopolymers of the present invention, it is preferable that the shrinkage reducing auxiliary agent contains a tartrate salt.

Moreover, in the admixture for geopolymers of the present invention, it is preferable that, in the shrinkage reducing agent, the ether compound includes one or more compounds represented by the following general formulas (2) and (3).
_{R 1 -O- (A 1 O)} n1 -R 2 (2)
(In the formula,
R ₁ and R ₂ each independently represent a hydrogen atom or a monovalent hydrocarbon group which may have an unsaturated bond having 1 to 22 carbon atoms,
A ₁ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms,
n1 is the average number of added moles of alkylene oxide and represents a number of 1 to 200;
When n1 is 2 or more, A ₁ O represents an alkyleneoxy group which may be the same or different. )
_{R 3 [-O- (A 2 O} ) n2 -R 4] m (3)
(In the formula,
R ₃ represents a residue obtained by removing m hydroxy groups from an m-valent polyhydric alcohol having 2 to 30 carbon atoms,
R ₄ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 22 carbon atoms and optionally containing an unsaturated bond,
A ₂ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms,
n2 is the average number of moles of alkylene oxide added and represents a number of 1 to 200;
When n2 is 2 or more, A ₂ O represents the same or different alkyleneoxy groups,
m represents an integer of 2 to 8. )

Furthermore, in the admixture for geopolymers of the present invention, it is preferable that in the shrinkage reducing agent, the ether compound contains one or more compounds represented by the following general formula (4).
_{R 5 -O- (A 3 O)} n3 -R 6 (4)
(In the formula,
R ₅ is a hydrogen atom, a linear primary alkyl group having 1 to 22 carbon atoms, a branched primary alkyl group having 3 to 22 carbon atoms, or a tertiary alkyl group having 4 to 22 carbon atoms Represents a linear alkenyl group having 2 to 22 carbon atoms, a branched alkenyl group having 3 to 22 carbon atoms, a (meth) acryloyl group, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms,
R ₆ is a hydrogen atom, a straight chain alkyl group having 1 to 22 carbon atoms, a branched chain alkyl group having 3 to 22 carbon atoms, a straight chain alkenyl group having 2 to 22 carbon atoms, or a branched chain having 3 to 22 carbon atoms. Represents a chain alkenyl group, a (meth) acryloyl group, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms,
A ₃ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms, n3 represents the average number of moles of added alkylene oxide and represents 1 to 200, and (A ₃ O) _n3 represents the same alkylene. Represents n3 consecutive chains of oxide. )
Furthermore, in a preferred embodiment, the ether compound is represented by the above formula (4):
R ₅ is a hydrogen atom, a linear primary alkyl group having 1 to 12 carbon atoms, a branched primary alkyl group having 3 to 12 carbon atoms, or a tertiary alkyl group having 4 to 12 carbon atoms Represents a linear alkenyl group having 2 to 4 carbon atoms, a branched alkenyl group having 3 to 4 carbon atoms, or a phenyl group,
R ₆ represents a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms,
A ₃ O represents a divalent alkylene oxide group having 2 or 3 carbon atoms, and n 3 is preferably a compound representing a number of 1 to 100.

In the admixture for geopolymers of the present invention, the shrinkage reducing agent is preferably a compound in which the ether compound has a weight average molecular weight (Mw) of 100 to 10,000.

  Moreover, in the admixture for geopolymers of the present invention, the shrinkage reducing agent is at least one aluminosilicate source having a CaO content of 1 to 60% by mass, and an alkali metal hydroxide, an alkali metal carbonate and an alkali metal. It is preferably an additive applied to a geopolymer formed from a mixture containing at least one alkali source selected from the group consisting of silicates.

Further, the present invention comprises the group consisting of the admixture for geopolymer, at least one aluminosilicate source having a CaO content of 1 to 60% by mass, an alkali metal hydroxide, an alkali metal carbonate and an alkali metal silicate. A geopolymer-forming composition comprising at least one alkali source selected and an aggregate.
Further, a cured product of the geopolymer-forming composition, that is, the admixture for geopolymer, at least one aluminosilicate source having a CaO content of 1 to 60% by mass, an alkali metal hydroxide, an alkali metal carbonate and The present invention relates to a cured geopolymer containing at least one alkali source selected from the group consisting of alkali metal silicates and an aggregate.

  The admixture for a geopolymer of the present invention has an excellent shrinkage-reducing effect in a geopolymer containing the same, and can adjust the setting time of the geopolymer, without impairing the strength development of the cured product, and the workability before curing. It is possible to obtain a geopolymer cured product that improves the surface appearance of the cured product and improves the appearance of the cured product.

As described above, the geopolymer (GP) is made of a material containing an aluminosilicate source (active filler) and an alkali source (alkali silica solution or the like). Here, the water contained in the GP forming material (GP forming composition) is different from the hydration reaction of Portland cement in conventional concrete, and is due to an aluminosilicate source and an alkali source, which are considered as one mode of the GP curing reaction. It is considered that it does not participate in the polycondensation reaction. Therefore, with the setting and curing of the GP-forming composition, water in the composition (in the alkaline solution) that does not participate in the curing reaction can be discharged to the outside of the system as steam. That is, it is considered that the drying shrinkage due to the dissipation of water has already occurred in GP from the setting stage. In fact, the inventors have confirmed that the dry shrinkage strain of GP concrete is much higher than that of conventional cement concrete.
Although it can be said that suppressing the drying shrinkage strain is one of the important problems in putting the GP into practical use, in a few reports on the drying shrinkage of the GP (for example, Non-Patent Document 7 and Non-Patent Document 8). However, specific means for reducing shrinkage, for example, components and constitutions that exert the effect of reducing shrinkage have not been sufficiently examined. In addition, although there is a report example (Patent Document 3) in which a conventional shrinkage reducing agent for concrete is mixed in concrete containing water glass and slag (water slag concrete), this report example has a large dry shrinkage at an initial age. I just focused on that. In addition, in aluminosilicate binders (alkali activated aluminosilicate binders) added with an alkali activator, there are reports that amine compounds are effective in reducing shrinkage (Patent Documents 4 and 5), There is no reference to oxyalkylene alkyl ether compounds.
The present invention adopts a composition of an admixture in which a shrinkage-reducing agent composed of a specific oxyalkylene alkyl ether compound and a shrinkage-reducing auxiliary agent composed of a specific aliphatic oxycarboxylic acid compound are adopted, whereby the GP is condensed. It was discovered that while suppressing the drying shrinkage that is considered to occur from the stage, it realizes both the adjustment of the setting time and the strength development of the cured product, and that the cured product has a good appearance. ..
Hereinafter, the present invention will be described in detail.

[Admixture for geopolymer]
TECHNICAL FIELD The present invention relates to an admixture for geopolymer, which contains a shrinkage reducing agent for geopolymer and a shrinkage reducing auxiliary agent for geopolymer.
In the admixture for geopolymers of the present invention, the compounding ratio of the shrinkage-reducing agent and the shrinkage-reducing auxiliary agent described later is not particularly limited, but for example, shrinkage-reducing agent: shrinkage-reducing auxiliary agent = 10: 1 to 1:10 ( Mass ratio), preferably (the same) 5: 1 to 1: 5.
The admixture for a geopolymer of the present invention is a form containing a shrinkage-reducing agent and a shrinkage-reducing aid described below, a form in which a known admixture other than the shrinkage-reducing agent and the shrinkage-reducing aid described below is blended, and a geopolymer (cured product). ) At the time of production, the shrinkage-reducing agent and the shrinkage-reducing aid in the admixture for a geopolymer of the present invention are added separately (or at least two kinds in combination), and finally in the geopolymer. Includes any of the mixed forms.

<Shrinkage reducer for geopolymer>
The shrinkage reducing agent used in the admixture for a geopolymer of the present invention contains an ether compound having a structure represented by the following general formula (1).
-O- (AO) n- (1)
In the above formula (1), AO represents a divalent alkylene oxide group having 2 to 4 carbon atoms, and n represents an average addition mole number of alkylene oxide and represents 1 to 200.
When n is 2 or more, AO may be composed of the same kind of alkylene oxide groups or two or more kinds of alkylene oxide groups. In the latter case, different kinds of alkylene oxide groups are It may be block addition or random addition.
The weight average molecular weight (Mw) of the ether compound having the structure represented by the general formula (1) and the compounds represented by the general formulas (2) to (4) described later is not particularly limited. However, for example, a compound having Mw of 100 to 10,000 is preferable, a compound having Mw of 100 to 5,000 is preferable, a compound having 100 to 1,000 is particularly preferable, and a compound having 100 to 500 is more preferable. Is preferred. In addition, in this specification, a weight average molecular weight (Mw) says the value measured by polystyrene conversion by gel permeation chromatography (GPC).

In the shrinkage reducing agent, it is preferable that the ether compound include one or more compounds represented by the following general formulas (2) and (3).
_{R 1 -O- (A 1 O)} n1 -R 2 (2)
In the above formula (2),
R ₁ and R ₂ each independently represent a hydrogen atom or a monovalent hydrocarbon group which may have an unsaturated bond having 1 to 22 carbon atoms,
A ₁ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms,
n1 is the average number of added moles of alkylene oxide and represents a number of 1 to 200;
When n1 is 2 or more, A ₁ O represents an alkyleneoxy group which may be the same or different.
_{R 3 [-O- (A 2 O} ) n2 -R 4] m (3)
In the above formula (3),
R ₃ represents a residue obtained by removing m hydroxy groups from an m-valent polyhydric alcohol having 2 to 30 carbon atoms,
R ₄ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 22 carbon atoms and optionally containing an unsaturated bond,
A ₂ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms,
n2 is the average number of moles of alkylene oxide added and represents a number of 1 to 200;
When n2 is 2 or more, A ₂ O represents the same or different alkyleneoxy groups,
m represents an integer of 2 to 8.

In the above formula, the monovalent hydrocarbon group for R ₁ , R ₂ and R ₄ which may contain an unsaturated bond having 1 to 22 carbon atoms includes an alkyl group and an alkenyl group having the above carbon number (see the following). And alkyl groups having 1 to 22 carbon atoms, alkenyl groups having 2 to 22 carbon atoms), monovalent aromatic hydrocarbon groups (benzene, naphthalene, anthracene, phenanthrene, chrysene, pyrene, perylene, etc.) and the like. ..
The said hydrocarbon group has a carbonyl bond (-C (= O)-), an ether bond (-O-), an ester bond (-C (= O) -O-, -OC (= O)-). , An amino bond (-NH-), an amide bond (-C (= O) -NH-, -NH-C (= O)-), and a group selected from the group consisting of a combination thereof. Good.
Further, the monovalent aromatic hydrocarbon group may contain a substituent described later.

Examples of the alkyl group having 1 to 22 carbon atoms include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group. Group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, heneicosyl group, docosyl group, and an alkyl group having 3 or more carbon atoms (that is, the above-mentioned methyl group and ethyl group. Except the above, the groups described after the propyl group) may include a branched chain and a cyclic chain.
Examples of the alkenyl group having 2 to 22 carbon atoms include ethanyl group, propanyl group, butanyl group, pentanyl group, hexanyl group, heptanyl group, octanyl group, nonanyl group, decanyl group, undecanyl group, dodecanyl group, tridecanyl group, Examples thereof include a tetradecanyl group, a pentadecanyl group, a hexadecanyl group, a heptadecanyl group, an octadecanyl group, a nonadecanyl group, an eicosanyl group, a heneicosanyl group, and a docosanyl group, and an alkenyl group having 3 or more carbon atoms (that is, a propanyl group except the above-mentioned ethanyl group. The groups described below) may include a branched chain or a cyclic chain.

The m-valent polyhydric alcohol having 2 to 30 carbon atoms in R ₃ may be a linear polyhydric alcohol or an unsaturated double bond, and may have a plurality of hydroxy groups at the same carbon atom. Represents a polyhydric alcohol which may be bonded, and when it has 3 or more carbon atoms, may contain a branched chain or a cyclic chain.
The m-valent polyhydric alcohol is specifically a compound having 2 to 8 hydroxy groups, and examples thereof include dihydric alcohols (ethylene glycol, diethylene glycol, propylene glycol, butanediol, neopentyl glycol and hexanediol). Trihydric to polyhydric alcohols (glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitan and diglycerin); sugars and their derivatives (sucrose, glucose, fructose and methylglycoside). Of these, polyhydric alcohols having 3 to 5 valences and sugars are preferably used, and more preferably sorbitol, sorbitan, polyglycerin, pentaerythritol, dipentaerythritol and sucrose.
Therefore, examples of the residue of R _{3 obtained} by removing m hydroxy groups from an m-valent polyhydric alcohol having 2 to 30 carbon atoms include an m-valent hydrocarbon group having 2 to 30 carbon atoms, The hydrocarbon group may contain an ether bond.
Note that the hydrocarbon group having a valence of 2 to 30 m is not particularly limited, but for example, an alkane having a carbon number of 2 to 30, an alkene having a carbon number of 2 to 30 can be used to convert a hydrogen atom to m. Examples thereof include groups excluding individual groups.
Examples of the alkane having 2 to 30 carbon atoms include ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, Heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, triacontane, and the like, which may be linear, branched, cyclic, or a combination thereof.
Examples of the alkene having 2 to 30 carbon atoms include ethene, propene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, octadecene, nonadecene, eicosene, heneicosene. , Docosene, tricosene, tetracocene, pentacocene, hexacocene, heptacocene, octacocene, nonacocene, triacontene, and the like, which may be linear, branched, cyclic, or a combination thereof.

Examples of the divalent alkylene oxide group having 2 to 4 carbon atoms in A ₁ O and A ₂ O include an ethylene oxide group, a propylene oxide group and a butylene oxide group (for convenience of description of the structural formula, It may be referred to as an oxyethylene group, an oxypropylene group, or an oxybutylene group, including the case where it is described as O ₁ A or OA ₂ (oxyalkylene group)).
When n1 and n2 are 2 or more, A ₁ O and A ₂ O may each be composed of the same kind of alkylene oxide group or two or more kinds of alkylene oxide groups, and in the latter case The different alkylene oxide groups may be block-added or random-added.

Above all, it is preferable that the shrinkage reducing agent contains one or more compounds represented by the following general formula (4) as the ether compound.
_{R 5 -O- (A 3 O)} n3 -R 6 (4)
In the above formula (4),
R ₅ is a hydrogen atom, a linear or branched primary or tertiary alkyl group having 1 to 22 carbon atoms (that is, a linear primary alkyl group having 1 to 22 carbon atoms, or 3 carbon atoms). To C22 branched-chain primary alkyl groups, C4 to C22 tertiary alkyl groups), and C2 to C22 straight-chain or branched alkenyl groups (that is, C2 to C22). A linear alkenyl group, a branched alkenyl group having 3 to 22 carbon atoms), a (meth) acryloyl group, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms,
R ₆ is a hydrogen atom, a linear or branched alkyl group having 1 to 22 carbon atoms (that is, a linear alkyl group having 1 to 22 carbon atoms, a branched alkyl group having 3 to 22 carbon atoms), carbon A straight chain or branched chain alkenyl group having 2 to 22 atoms (that is, a straight chain alkenyl group having 2 to 22 carbon atoms, a branched chain alkenyl group having 3 to 22 carbon atoms), a (meth) acryloyl group, or carbon Represents a monovalent aromatic hydrocarbon group having 6 to 22 atoms,
A ₃ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms, n3 represents the average number of moles of added alkylene oxide and represents 1 to 200, and (A ₃ O) _n3 represents the same alkylene. Represents n3 consecutive chains of oxide.

Examples of the linear or branched alkyl group having 1 to 22 carbon atoms in R ₅ and R ₆ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-octyl group, n-decyl group, dodecyl group (lauryl group), tetradecyl group (myristyl group), hexadecyl group ( Palmyl group), octadecyl group (stearyl group), icosyl group, docosyl group (behenyl group) and the like.
Examples of the straight-chain or branched-chain alkenyl group having 2 to 22 carbon atoms include the groups having one carbon-carbon double bond in the groups mentioned as the alkyl group having 1 to 22 carbon atoms. .. Specifically, an ethenyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, a dodecenyl group, a tetradecenyl group, a hexadecenyl group, an octadecenyl group, an eicosenyl group, a docosenyl group, etc. Is mentioned.
Examples of the (meth) acryloyl group include a methacryloyl group and an acryloyl group.
Examples of the monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms include monovalent groups having an aromatic ring such as benzene, naphthalene, anthracene, phenanthrene, chrysene, pyrene and perylene. The monovalent aromatic hydrocarbon group may contain a substituent, and as the substituent, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), or a substituent thereof may be used. Examples thereof include a monovalent hydrocarbon group having 1 to 22 carbon atoms (such as an alkyl group having 1 to 22 carbon atoms and an alkenyl group having 2 to 22 carbon atoms, which are exemplified in R ₁ and the like).

Examples of the divalent alkylene oxide group having 2 to 4 carbon atoms in A ₃ O include an ethylene oxide group, a propylene oxide group, and a butylene oxide group (for convenience of description of the structural formula, O ₃ A (oxy)). (Alkylene group), sometimes including oxyethylene group, oxypropylene group, oxybutylene group).
Note that (A ₃ O) _n3 represents n3 continuous chains of the same alkylene oxide means that one compound contains a plurality of alkylene oxide groups (for example, both ethylene oxide groups and propylene oxide groups). Means no.

In a preferred embodiment, the ether compound is a compound represented by the above formula (2):
R ₅ is a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms (that is, a linear primary alkyl group having 1 to 12 carbon atoms, a branched chain primary alkyl group having 3 to 12 carbon atoms). Primary alkyl group, tertiary alkyl group having 4 to 12 carbon atoms), branched chain alkenyl group having 2 to 4 carbon atoms (that is, linear alkenyl group having 2 to 4 carbon atoms, 3 to 4 carbon atoms) A branched alkenyl group), or a phenyl group,
R ₆ represents a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms,
A ₃ O represents a divalent alkylene oxide group having 2 or 3 carbon atoms, and n 3 is preferably a compound representing a number of 1 to 100.

<Shrinkage reduction aid for geopolymer>
The admixture for geopolymers of the present invention further contains a shrinkage reducing auxiliary agent in addition to the shrinkage reducing agent. The shrinkage-reducing aid may be used without limitation as long as it has a function of further enhancing the shrinkage-reducing effect of the shrinkage-reducing agent used in the admixture of the present invention, and as an example, an additive exhibiting a setting retarding effect. Etc. can be used.
In the present invention, from the viewpoint of further enhancing the shrinkage reducing effect, as a preferred shrinkage reducing auxiliary agent, one or more aliphatic oxycarboxylic acids having a specific hydroxyl value and acid value, and a specific hydroxyl value / acid value. An acid salt is used.

In the shrinkage reduction aid, the aliphatic oxycarboxylic acid has a hydroxyl value of 250 to 1500 mgKOH / g and an acid value of 250 to 950 mgKOH / g, and a hydroxyl value which is a ratio of the hydroxyl value and the acid value. / Use an acid value of 0.40 or more and less than 5.00. The hydroxyl value / acid value is preferably 0.50 or more and 4.00 or less, and more preferably 1.00 or more and 4.00 or less.
When two or more kinds of aliphatic oxycarboxylic acids are used, the ratio of the hydroxyl value to the acid value is defined as the weight value averaged hydroxyl value / the same weight averaged acid value of the plurality of aliphatic oxycarboxylic acids used. Is calculated. Further, when the weight-averaged hydroxyl value / acid value in the case of using plural kinds in combination is within the above numerical range (0.40 or more and less than 5.00), the aliphatic oxycarboxylic acid 1 If only the seed is used, it can be used even if the ratio of the hydroxyl value to the acid value is out of the above numerical range.

Examples of the aliphatic oxycarboxylic acid include glycolic acid, lactic acid, tartronic acid, glyceric acid, 2-hydroxybutyric acid, γ-hydroxybutyric acid, 3-hydroxybutyric acid, tartaric acid, malic acid, citric acid, isocitric acid, mevalonic acid, pantoin. Examples thereof include aliphatic or alicyclic oxycarboxylic acids such as acid, gluconic acid, quinic acid, and shikimic acid. These aliphatic oxycarboxylic acids can be used alone or in combination of two or more.

Among them, preferable aliphatic oxycarboxylic acids include lactic acid, malic acid, tartaric acid, citric acid, and gluconic acid, more preferably lactic acid, malic acid, and tartaric acid, among which tartaric acid, among which L-tartaric acid is easily available. Is most preferred.
Further, when two or more kinds are used in combination, it is preferable to use tartaric acid in at least one of them in order to suppress the occurrence of efflorescence in the appearance of the cured product and to obtain a preferable surface appearance. When two or more kinds are used in combination, preferred combinations include, for example, tartaric acid and malic acid, tartaric acid and gluconic acid, and the like.

  Examples of the salt of these aliphatic oxycarboxylic acids include alkali metal salts such as lithium salt, sodium salt and potassium salt, preferably sodium salt.

[Geopolymer-forming composition / geopolymer]
As described above, the geopolymer to which the above-mentioned admixture of the present invention is applied is composed of a mixture containing an aluminosilicate source such as an active filler, an alkali source such as an alkali silica solution, and an aggregate.
Incidentally, the present invention, the admixture for the geopolymer, a geopolymer-forming composition containing an aluminosilicate source such as the active filler constituting the geopolymer and an alkali source such as an alkali silica solution, and an aggregate to be described later, and A geopolymer cured product which is a cured product of the geopolymer-forming composition is also intended.

The geopolymer to which the admixture for geopolymer of the present invention is applied is supposed to contain at least one kind of various active fillers described below as an aluminosilicate source, and a so-called water glass described below as an alkali source. It is supposed to be contained.
The geopolymer targeted by the admixture of the present invention contains, for example, 0 to 100% by mass of fly ash and 100 to 0% by mass of blast furnace slag fine powder as the aminosilicate source (total 100% by mass). From which at least one aluminosilicate source having a CaO content of 1 to 60% by mass and an alkali metal hydroxide, an alkali metal carbonate and an alkali metal silicate can be used. It is possible to use an object that includes at least one selected alkali source.

<Aluminosilicate source: Active filler>
The aluminosilicate source refers to a component containing aluminosilicate (xM ₂ O.yAl ₂ O ₃ .zSiO ₂ .nH ₂ O, M is an alkali metal) as a component, and is referred to as a highly alkaline solution (alkali silica solution). Upon contact, it elutes cations such as aluminum and silicon, and acts as a supply source of them.
Suitable examples of aluminosilicate sources include 1) fly ash, clinker ash, fluidized bed coal ash, blast furnace slag fine powder, municipal solid waste incinerated ash molten slag fine powder, red mud, and sewage sludge incinerated ash molten slag fine powder. Industrial wastes and by-products, 2) natural aluminosilicate minerals such as metakaolin and clay and its burnt products, 3) volcanic ash can be mentioned.
Among these, the industrial waste of the above 1) is particularly preferable, as compared with other aluminosilicate sources, because it has no restrictions on the production site and leads to effective utilization of industrial waste resources.
In the present invention, it is preferable to use at least one aluminosilicate source having a CaO content of 1 to 60 mass%. For example, as an aluminosilicate source having a CaO content of about 1 to 10% by mass, fly ash and clinker ash can be mentioned. Further, as an aluminosilicate source having a relatively high CaO content of 10 to 60% by mass, for example,
Blast furnace slag fine powder, municipal solid waste incineration ash slag fine powder, sewage sludge incinerator ash slag fine powder, CaO-rich fluidized bed coal ash and the like can be mentioned. As one of the preferred embodiments of the present invention, there is mentioned an embodiment in which at least one of the aluminosilicate sources having a relatively high CaO content and fly ash are mixed and used, and in particular, blast furnace slag fine powder and fly ash are mixed and used.

The blast furnace slag fine powder is a by-product when refining iron in a blast furnace, contains calcium oxide (CaO), silica (SiO ₂ ), and alumina (Al ₂ O ₃ ) as main components, and is specified in JIS A6206. Particularly, the blast furnace slag fine powder to be used preferably has a CaO content in the range of 30 to 60 mass%.
Municipal solid waste incineration ash slag is obtained by melting and cooling the ash produced during the incineration of municipal solid waste at high temperatures, and, like blast furnace slag, contains oxides of silicon, aluminum and calcium as its main components. is there. A CaO content of 15 to 45% by mass is preferably used.
Fluidized bed coal ash is ash generated from a pressurized fluidized bed coal boiler. Since limestone fine powder is mixed for the purpose of desulfurization in the furnace to burn coal, it is characterized by containing more CaO than fly ash and clinker ash described later. Although fluidized bed coal ash does not satisfy the current JIS standard (JIS A 6201) of fly ash for concrete admixtures, it can be used as a source of alkali silicate. The CaO content is 20 to 55 mass% although it varies depending on the ash generation site.
The sewage sludge incineration ash molten slag is obtained by concentrating and dewatering sludge generated by the treatment of sewage, and then melting and cooling the ash incinerated at about 800 ° C at a higher temperature. Sewage sludge incineration ash is classified according to the type of coagulant added during dehydration, that is, it is classified into lime-based incineration ash containing slaked lime and ferric chloride and polymer-based incineration ash containing polymer coagulant. . The CaO content of the lime-based incineration ash varies depending on the addition rate of slaked lime during dehydration, but is generally about 30 to 50 mass%. On the other hand, the content of CaO in the high-polymer incineration ash is about 10 mass% or less. Therefore, as the aluminosilicate source used in the present invention, it is preferable to use slag from lime-based incineration ash.

Fly ash contains silica (SiO ₂ ) and alumina (Al ₂ O ₃ ) as main components, and is specified in JIS A 6201 as I to IV types (JIS A6201) based on particle size and flow value. JIS type I and type II, which have a fine particle size and are highly reactive, are particularly suitable as a geopolymer raw material. The content of CaO in fly ash is set to about 10.1% by mass.
Clinker ash is obtained by crushing the coal-like coal ash collected at the bottom of the coal-fired boiler. The content of CaO in the clinker ash is set to about 2 to 9% by mass.
In both fly ash and clinker ash, since silica (SiO ₂ ) and alumina (Al ₂ O ₃ ) components account for 70 to 90% of the total mass, they are useful as a source of alkali silicate.

As described above, the geopolymer (geopolymer forming composition / geopolymer cured product) to which the admixture for geopolymer of the present invention is applied is at least one aluminosilicate having a CaO content of 1 to 60% by mass. Source, specifically, blast furnace slag fine powder, municipal solid waste incineration ash slag fine powder, sewage sludge incineration ash molten slag fine powder, and fluidized bed coal ash (rich in CaO), and aluminosilicate sources with relatively high CaO content Or at least one aluminosilicate source such as fly ash or clinker ash having a low CaO content as an aluminosilicate source (active filler).
The mixing ratio of the aluminosilicate source having a high CaO content in the active filler is 1% by mass to 100% by mass, preferably 10% by mass to 100% by mass, based on the total mass of the active filler. It is preferably at least 20% by mass.
When two or more kinds of active fillers are used, the proportion of CaO in the whole active filler is 1 to 60% by mass, preferably 10% to 60% by mass. The CaO content can be adjusted by changing the proportion of the fine powder or ash having a high CaO content.

<Alkali source: Alkali silica solution>
In the present invention, the alkali source refers to an aqueous solution of a compound exhibiting high alkalinity, and has a function of activating cations such as aluminum and silicon by contacting the aluminosilicate source to activate them.
The compounds used as the alkali source include 1) alkali hydroxides such as sodium hydroxide and potassium hydroxide, 2) alkali carbonate salts such as sodium carbonate and potassium carbonate, 3) sodium silicate, potassium silicate and silicic acid. In addition to alkali silicates such as lithium, combinations of these 1) to 3) can be preferably used.

Of the above, the sodium compound is more preferable in terms of price.
Further, 3) the case of using an alkali silicate is more preferable because it itself serves as a supply source of the silicic acid monomer (Si (OH) ₄ ) which is entrusted to the formation of the geopolymer.
From these viewpoints, preferred examples of the compound as the alkali source include sodium silicate, sodium hydroxide, and a combination of sodium silicate and sodium hydroxide. Further, it is possible to replace a part of the sodium compound with a corresponding potassium compound as long as the economical efficiency (cost) in industrial implementation is not impaired.
Therefore, as the alkali source, an aqueous solution of potassium hydroxide, sodium hydroxide, sodium silicate or potassium silicate is preferably used, and a sodium silicate aqueous solution is particularly preferably used.
The aqueous sodium silicate solution is commonly called "water glass", and a commercially available product can be used. The chemical composition preferably contains SiO ₂ = 20-40% and Na ₂ O = 5-20%.
In the present invention, when water glass is used as the alkali source, in a preferred embodiment, when the molar ratio of SiO ₂ and Na ₂ O: SiO ₂ / Na ₂ O is 2.1 or more, a large amount of waste is generated. From the viewpoint of utilization, the ratio (mass) of the blast furnace slag fine powder in the active filler is preferably less than 50%.

It is desirable that the molar ratio of the amount of alkali to the amount of water (hereinafter referred to as the molar ratio) that constitutes the alkali source is 0.1 or more. The higher the molar ratio is within a reasonable range, the better the strength development of the obtained geopolymer cured product, so it is necessary to increase the amount of alkali added during kneading and reduce the amount of water. The fluidity is reduced and it becomes difficult to fill the mold. Therefore, the molar ratio is more preferably 0.15 or more.
The concentration of the aqueous alkaline solution used is preferably in the range of 20 to 50% by mass.

<Geopolymer-forming composition / geopolymer cured product>
When a plurality of active fillers are used in the production of the geopolymer-forming composition, these are mixed to prepare an aluminosilicate source. A separately prepared alkali source is added to and mixed with an aluminosilicate source, further aggregate is added and mixed, and the admixture of the present invention is added as described below to produce a geopolymer-forming composition.
The present invention is based on the group consisting of the above-mentioned admixture for geopolymer, at least one aluminosilicate source having a CaO content of 1 to 60% by mass, an alkali metal hydroxide, an alkali metal carbonate and an alkali metal silicate. Also intended are hardened geopolymers, which include at least one alkali source selected and aggregates.

  As the aggregate, those generally used for general concrete and mortar (fine aggregate, coarse aggregate, etc.) can be preferably used.

The admixture for geopolymer of the present invention may be added together when preparing an alkali source, or may be added after kneading the alkali source, aluminosilicate source and aggregate, and evenly mixed. Good. It is also possible to use the admixture for geopolymer as an aqueous solution or as a solid. It is also possible to prepare the geopolymer-forming composition using an aluminosilicate source and an admixture for a geopolymer and / or an aqueous solution of the admixture, which have been premixed.
In this way, the admixture for geopolymer may be mixed with either an aluminosilicate source or an alkali source and further mixed with the remaining materials used for the geopolymer, or a mixture of a premixed aluminosilicate source and an alkali source. However, the latter (addition to the mixture) is preferred. As a method of addition, the required addition amount may be added all at once, or the required addition amount may be divided and added. Further, for example, the shrinkage-reducing agent can be added as a part of the admixture and kneaded first, and then the shrinkage-reducing auxiliary agent can be added.
Regarding the blending design of the geopolymer, the ratio of the total mass of the alkali solution (alkali source: eg water glass + sodium hydroxide hydroxide + water) and the total mass of the aluminosilicate source (active filler powder (B)) ([alkaline solution / B ] × 100 (%)) can be appropriately set depending on the strength required for the structure or product, but is preferably 40 to 65 mass% in consideration of workability.
Further, the ratio of the constituents of the alkaline solution, for example, the mass ratio represented by [total mass of water glass (WG)] / [total mass of sodium hydroxide (NaOH) or aqueous sodium hydroxide solution (NaOHaq)] is It can be appropriately set depending on the target setting time and strength of the polymer (cured product), but is preferably in the range of 1.0 to 4.0. This ratio can also be set by the volume ratio of water glass and aqueous sodium hydroxide solution.
The mixing ratio of the admixture for a geopolymer can be variously changed depending on the constitution of the admixture and the constitution of the geopolymer-forming composition (material used for the geopolymer) (for example, constitution of aluminosilicate source). The amount of the aluminosilicate source can be 1 to 30% by mass, for example, 5 to 20% by mass.

  The present invention will be described below with reference to examples. However, the present invention is not limited to these Examples and Comparative Examples.

[Preparation of shrinkage reduction aid for geopolymer]
An oxycarboxylic acid compound shown in Table 1 and a 48 mass% sodium hydroxide aqueous solution (manufactured by Kaneka Corporation, product name "caustic soda", specific gravity at 35 ° C: 1.504, pure content: 48%, molar concentration: 18.1 mol / L) and ion-exchanged water were used to prepare the shrinkage reducing auxiliary agent for geopolymer (30% aqueous solution of sodium salt) shown in Table 2 by a neutralization reaction. The molar ratio of oxycarboxylic acid (acid) and sodium hydroxide (alkali) was 1: 1. Then, the aqueous solution of the shrinkage-reducing auxiliary agent for geopolymer was heated, concentrated, recrystallized, and fractionated to obtain a solid shrinkage-reducing auxiliary agent (sodium salt) for geopolymer (A1, B1, B2). In the following examples of geopolymer mortar, the shrinkage reducing auxiliary agent for geopolymer in the form of an aqueous solution and the shrinkage reducing auxiliary agent for geopolymer in the form of solid were used together in order to have the amount of water necessary for blending the mortar.

[Preparation of shrink reducing agent for geopolymer]
Table 3 shows shrinkage reducing agents X1 to X9 for geopolymers and comparative shrinkage reducing agents Y3 to Y7 used in the examples.
In addition, among the shrinkage reducing agents used in the comparative examples, Y3 and Y4 are the shrinkage reducing agents disclosed in the examples (Example 23 and Comparative example 14) of Japanese Patent No. 4677181, and Y5 is the special table 2015-536294. It is a freeze-thaw stabilizer disclosed in the examples (Example No. 7) of the publication.

[Preparation of alkaline solution used in test]
48 mass% sodium hydroxide aqueous solution (manufactured by Kaneka Corporation, product name “caustic soda”, specific gravity at 35 ° C .: 1.504, pure content: 48%, molar concentration: 18.1 mol / L) per 100 mass parts Then, 20 parts by mass of ion-exchanged water was added and mixed to prepare a 40% by mass aqueous sodium hydroxide solution (specific gravity: 1.43, molar concentration: 14.3 mol / L).
Similarly, to 100 parts by mass of the 48% by mass sodium hydroxide aqueous solution, 60 parts by mass of ion-exchanged water is added and mixed, and a 30% by mass aqueous sodium hydroxide solution (specific gravity: 1.33, molar concentration 10.0 mol / L ) Was prepared.

40 mass% or 30 mass% sodium hydroxide aqueous solution (NaOHaq) prepared by the above procedure and sodium silicate (WG) (manufactured by Fuji Chemical Co., Ltd., product name "sodium silicate No. 1", density: 1.534) , SiO ₂ / Na ₂ O molar ratio = 2.1, SiO ₂ : 30%, Na ₂ O: 15%) and ion-exchanged water (W) are shown in Table 4 and Table 12 (mortar) and Table 5 (concrete). ) Are mixed and mixed according to the unit amount (g), and No. An alkaline solution (GP solution) shown in M1 to M6 and C1 was prepared.
The alkaline solution does not include a shrink reducing agent for geopolymers and a shrink reducing aid for geopolymers.

[Preparation of geopolymer mortar used for test]
The shrinkage reducing agent for geopolymers shown in Table 3 and the shrinkage reducing auxiliary agent for geopolymers shown in Table 2 are
3% by mass and 5% by mass, respectively, with respect to the mass (g) of the active filler B shown in Table 4 and Table 12 (mortar) and Table 5 (concrete) or the mass (g) of the municipal waste incineration ash molten slag fine powder WS. Alternatively, it was added at a ratio of 7% by mass (solid content conversion). In addition, alkaline solution / B (fly ash + blast furnace slag fine powder) or alkaline solution / WS (urban waste incineration ash molten slag fine powder) shown in Table 4 and Table 12 (mortar) and Table 5 (concrete) (all are mass ratio). ,%) Is a value calculated from the amount of each component used.

[Geopolymer Mortar / Geopolymer Concrete Evaluation Test]
<Measurement of fluidity (mortar flow value)>
A high power mixer (manufactured by Maruto Co., Ltd .: CB-34) was used for kneading the geopolymer mortar. No. of Table 4 or Table 12. In the formulations shown in M1 to M6, the active fillers used were JIS II type fly ash (FA) and blast furnace slag fine powder 4000 (BFS), or municipal solid waste incinerated ash fused slag fine powder (WS). The alkaline solution, the shrinkage reducing agent for geopolymer, and the shrinkage reducing agent for geopolymer prepared in the above-mentioned procedure were weighed in proportions to the respective predetermined active fillers, mixed, and then added to the active fillers, at a low speed (revolution 62 rpm). , Rotation (141 rpm) for 120 seconds.
After the end of the low speed stirring, the operation of the mixer was stopped, and within 30 seconds after the operation was stopped, the mixer was operated as No. 4 in Table 4 or Table 12 as fine aggregate (S). Standard sand for cement strength test was added with the composition (unit amount) shown in M1 to M6, and the mixture was stirred again at low speed for 30 seconds, and then rapidly stirred at high speed (revolution 125 rpm, rotation 284 rpm) for 60 seconds. After completion of high-speed stirring, the produced geopolymer mortar was filled in a JIS flow cone, and the fluidity of the mortar (mortar flow) was measured according to JIS A1171.

<Measurement of fluidity (fresh concrete slump)>
A gravity type mixer having a capacity of 100 L was used for mixing the geopolymer concrete. No. of Table 5 In the formulation shown in C1, the active filler used was JIS II type fly ash (FA) and blast furnace slag fine powder 4000 (BFS). The alkaline solution prepared by the above procedure, the shrinkage reducing agent for geopolymer and the shrinkage reducing aid for geopolymer were weighed and mixed at a ratio to a predetermined active filler, and then the active filler was added and stirred for 60 seconds. Then, in Table 5, No. With the composition (unit amount) shown in C1, river sand was added to the mixer as fine aggregate (S) and stirred for 120 seconds, and then lime crushed stone was added to the mixer as coarse aggregate (G) and stirred for 120 seconds. After completion of the kneading, the slump was measured according to JIS A 1101.

<Measurement time>
The setting time was measured by the following procedure.
《Geopolymer mortar》
The geopolymer mortar produced by the above procedure was used as a sample container (upper end outer diameter φ90 mm, upper end inner diameter φ75 ± 3 mm, lower end outer diameter φ100 mm, lower end inner diameter φ85 ± 3 mm, height 40.0 ± 0.5 mm truncated cone shape ) And used for the measurement of setting time. The starting time was set to the time when the starting standard needle installed in the Bigger needle device stopped approximately 1 mm from the upper surface of the bottom plate. On the other hand, the termination time was set when a termination standard needle was installed in the biga needle device and the trace of the needle was stopped on the surface of the geopolymer mortar, but the trace by the attached small piece ring was not left. The starting and ending times were based on the time when the mixing of the active filler and the alkaline solution was started.
《Geopolymer concrete》
The geopolymer concrete produced by the above procedure was filled in a cylindrical sample container (made of plastic of φ10 cm × 20 cm) and used for the measurement of setting time. Under a condition of room temperature of 20 ± 2 ° C., the smoothed sample surface was pierced with a stick for a slump test at predetermined time intervals, and the time until the impression was clearly left was measured, which was taken as the initial time. On the other hand, the termination time was defined as the termination time by measuring the time until no trace of the stick was left when the surface of the geopolymer concrete was pierced (the stick with the stick did not stick to the sample). The starting and ending times were based on the time when the mixing of the active filler and the alkaline solution was started.

<Shrinkage strain measurement>
《Geopolymer mortar》
No. of Table 4 or Table 12. A geopolymer mortar prepared with the composition shown in M1 to M6 was filled in a plastic mold having a size of φ5 cm and a height of 10 cm to prepare a test piece, and an implantable strain manufactured by Kyowa Denki Co., Ltd. at the center of the test piece. A gauge (KMC-70-120-H4) was inserted, the upper surface was covered with a food wrap film (manufactured by Asahi Kasei Home Products Co., Ltd.), and sealed. After sealing the specimen, the specimen was cured at 20 ° C. for 1 day, and then the specimen was demolded. The age at the time of demolding was set to 1 day. After that, the specimen was subjected to air curing for 3 weeks under the conditions of a temperature of 20 ° C. and a relative humidity of 60%, and the length was changed by using a data logger (NTB-100A-120) connected to an implantable strain gauge. Was measured to determine the shrinkage strain (μm / m).
《Geopolymer concrete》
No. of Table 5 A columnar sample container (made of plastic of φ10 cm × 20 cm) was filled with the geopolymer concrete prepared with the composition shown in C1 to obtain a sample. At the production stage (geopolymer concrete filling stage) of the sample, an embedded strain gauge having a center length of 60 mm (an embedded strain gauge (KMC-70-120-H4) manufactured by Kyowa Denki Co., Ltd.) was used. The test piece was placed at the center of the test piece, the upper surface was covered with a food wrap film (manufactured by Asahi Kasei Home Products Co., Ltd.), and sealed. After sealing the specimen, the specimen was cured at 20 ° C. for 1 day, and then the specimen was demolded. The age at the time of demolding was set to 1 day. After that, the specimen was subjected to air curing for 6 weeks under the conditions of temperature of 20 ° C. and relative humidity of 60%, and the length was changed using a data logger (NTB-100A-120) connected to an implantable strain gauge. Was measured to determine the shrinkage strain (μm / m).

<Measurement of compressive strength of cured product and evaluation of surface appearance>
《Geopolymer mortar》
When measuring the compressive strength of geopolymer mortar, a plastic mold similar to the above <Measurement of shrinkage strain> was used, and the geopolymer mortar prepared above was filled into this mold, and the top surface was wrapped with food (Asahi Kasei Home Products). (Manufactured by Co., Ltd.), and the specimen was sealed. After sealing the specimen, the specimen was cured at 20 ° C. for 1 day, and then the specimen was demolded. The age at the time of demolding was set to 1 day. Thereafter, the specimen was subjected to air curing at a temperature of 20 ° C. and a humidity of 60% for 28 days (age 28 days).
The compressive strength of each specimen with a material age of 28 days was measured according to the procedure of JIS A 1108. For each example or comparative example, the compression strength (N / mm ² ) was defined as the average value of three test specimens at 28 days of age.
Further, the appearance (blackening / white flower) of the cured geopolymer mortar (material age 28 days) obtained by the above procedure was evaluated according to the following criteria. It should be noted that no change was observed in the appearance after the end of air curing (28 days old) in comparison with 1 day old in any sample.
・ Appearance (blackness / white flower) Evaluation criteria
×: Black spots were noticeably observed on the surface of the specimen, and white sinter was also noticeable △: Black stains were noticeably observed on the surface of the specimen, but white sinter was not observed ○: Dark spots on the surface of the specimen Is slightly observed, but white sinter is not confirmed. ◎: No darkening or white sinter is observed on the surface of the specimen.

《Geopolymer concrete》
In measuring the compressive strength of geopolymer concrete, the same cylindrical sample container as in <Measurement of shrinkage strain> described above was used, and this was filled with geopolymer concrete, and the top surface was wrapped with food (Asahi Kasei Home Products Co., Ltd.). Manufactured) and sealed the specimen. After sealing the specimen, the specimen was cured at 20 ° C. for 1 day, and then the specimen was demolded. The age at the time of demolding was set to 1 day. After that, the specimen was subjected to air curing at 20 ° C. and a humidity of 60% for 28 days.
The compressive strength of each specimen with a material age of 28 days was measured according to the procedure of JIS A 1108. For each example or comparative example, the compression strength (N / mm ² ) was defined as the average value of three test specimens at 28 days of age.
Further, the appearance (blackening / white flower) of the cured geopolymer concrete (age 28 days) obtained by the above procedure was evaluated according to the following criteria. It should be noted that no change was observed in the appearance after the end of air curing (28 days old) in comparison with 1 day old in any sample.
-Appearance (black spots / white sinter) Evaluation Criteria x: Black spots are noticeably observed on the surface of the specimen, and white sinter is also noticeably observed.
Δ: Black spots are conspicuously observed on the surface of the specimen, but white sinters are not observed. ○: Black spots are slightly observed on the surface of the specimen, but white sinters are not observed. ◎: Black spots / white sinters on the surface of the specimens. Is not observed at all

Performed on GP mortar produced by using fly ash and blast furnace slag fine powder as active filler, fluidity of GP mortar (mortar flow value), setting time, compressive strength, evaluation of surface appearance of cured product, and shrinkage strain The test results are shown in Tables 6 to 10. Table 11 shows the fluidity (slump value) of GP concrete, the setting time, the compressive strength, the evaluation of the surface appearance of the cured product, and the test result of the shrinkage strain, which were carried out on GP concrete. Show.
Also, the fluidity (mortar flow value), setting time, compressive strength, evaluation of the surface appearance of the cured product, and contraction strain test conducted on GP mortar produced by using municipal waste incineration ash molten slag fine powder as an active filler. The results are shown in Table 13.

As described above, in the geopolymer, it is considered that the drying shrinkage due to the dissipation of water occurs from the setting stage, and it is particularly important as an additive for the geopolymer that the drying shrinkage can be reduced. Will be one of.
From the test results of the geopolymer mortars shown in Tables 6 to 10 and 13 (Examples 1 to 45, 47) and the test results of the geopolymer concrete shown in Table 11 (Example 46), the present invention was obtained. By using the admixture for geopolymers containing the shrinkage reducing agent for geopolymer and the shrinkage reducing auxiliary agent, a comparative example in which neither the shrinkage reducing agent nor the shrinkage reducing auxiliary agent is used (Comparative Examples 1, 8, 15, 22) , 29, 36, 39), the shrinkage strain of the geopolymer (cured product) was reduced by about 50% or more, and the initial time of setting was extended by 1.7 to 3.5 times. In addition, comparative examples using comparative shrinkage reducing agents Y3 to Y5 (Comparative Examples 3 to 5, 10 to 12, 17 to 19, 24 to 26, 31 to 33) and comparative shrinkage reducing agents Y6 and Y7 were compared. Comparative Example (Comparative Examples 6, 7, 13, 14, 20, 21, 27, 28, 34, 35) in which the shrinkage reducing auxiliary agent B1 or B2 is used in combination, and further the shrinkage reduction used in the admixture of the present invention Compared with the comparative examples (Comparative Examples 2, 9, 16, 23, 30, 37, 38) using only the auxiliary agent A1, the result was obtained that the shrinkage strain was reduced by about 50%.

Further, as shown in the above results, the geopolymer-forming composition (geopolymer mortar / geopolymer concrete) in which the admixture for geopolymer containing the shrinkage reducing agent for geopolymer and the shrinkage reducing auxiliary agent of the present invention is blended, It becomes possible to appropriately adjust the setting time (for example, to extend the time to about 40 to 80 minutes), that is, the workability of driving can be improved, and the strength development of the cured product is not impaired. It was confirmed that a geopolymer (cured body) having an excellent appearance could be obtained.
When the time required for transportation and placement of the geopolymer is long, the fluidity of the geopolymer is greatly reduced due to water evaporation and curing reaction. In this case, adjustment of the curing reaction rate is important. From the test results of the setting time of the geopolymer mortars shown in Tables 6 to 10 and Table 13 and the test results of the setting time of the geopolymer concrete shown in Table 11, long-term workability was obtained by using the admixture of the present invention. It has been confirmed that it is possible to secure the above and that the working time can be adjusted.

In addition, the admixture for geopolymers of the present invention, that is, in combination with a specific shrinkage reducing agent and a specific shrinkage reducing aid, in a geopolymer using a filler having a high CaO content (for example, blast furnace slag fine powder), The shrinkage strain can be greatly reduced, and the initial setting time can be extended by 1.7 to 3.5 times (ratio of initial setting time when admixture is used and when not used). It was also confirmed that a high-strength geopolymer cured product could be produced without lowering the strength development compared with the comparative example.

JP, 2014-28726, A JP2012-240852A Patent No. 4677181 Japanese Patent Publication No. 2015-53624 International Publication No. 2010/130582

J. Davidovits, Properties of geopolymer cements, Proceedings of 1st International Conference on Alaline Cements and Concrete, KIEV, Ukraine, pp.131-149, 1994 D. Hardjito and B.V.Ranga, Development and properties of low-calcium fly ash-based geopolymer concrete, Research Report, Curtin University of Technology, pp 48-49, 2005 F. Puetras et al., Alkali-activated fly ash / slag cement strength behavior and hydration products, Cement and Concrete Research, Vol. 30, pp.1625-1632, 2000 Kazuo Ichinomiya et al. Mixture of fly ash-based geopolymer and high temperature resistance, Annual Review of Concrete Engineering, Vol. 36, No. 1, pp.2230-2235, 2014 Andri Kusbiantoro, et al., Development of sucrose and citric acid as the natural based admixture for fly ash based geopolymer, Proceedings of 3rd International Conference on Sustainable Future for Human Security, 2012 T.W.Cheng, J.P. Chiu, Fire-resistant geopolymer produced by granulated blast furnace slag, Minerals Engineering, Vol. 16, pp.205-210, 2003 Masato Honma, Shrinkage characteristics of geopolymer mortar that has been heated and cured, Summary of Academic Lectures by the Architectural Institute of Japan (Kinki), pp.355-356, 2014 M. Palacios, F. Puertas, Effect of shrinkage-reducing admixtures on the properties of alkali-activated slag mortars and pastes, Cement and Concrete Research, Vol. 37, pp.691-702, 2007

Claims (9)

The following general formula (1)
-O- (AO) n- (1)
[In the formula, AO represents a divalent alkylene oxide group having 2 to 4 carbon atoms, and n represents an average addition mole number of alkylene oxide and represents 1 to 200. ]
A shrinkage reducing agent for a geopolymer containing an ether compound having a structure represented by:
A mass-weighted average of the hydroxyl value / acid value of the aliphatic oxycarboxylic acid, including a salt of at least one aliphatic oxycarboxylic acid having a hydroxyl value of 250 to 1500 mgKOH / g and an acid value of 250 to 950 mgKOH / g. A shrinkage reducing auxiliary agent for geopolymer having a value of 0.40 or more and less than 5.00,
The shrinkage-reducing aid contains at least one salt of an aliphatic oxycarboxylic acid selected from the group consisting of lactate, malate, and tartrate.
Admixture for geopolymer. The admixture for a geopolymer according to claim 1, wherein the shrinkage reduction aid contains a tartrate salt. The admixture for geopolymers according to claim 1 or 2, wherein the ether compound includes one or more compounds represented by the following general formulas (2) and (3).
_{R 1 -O- (A 1 O)} n1 -R 2 (2)
(In the formula,
R ₁ and R ₂ each independently represent a hydrogen atom or a monovalent hydrocarbon group which may have an unsaturated bond having 1 to 22 carbon atoms,
A ₁ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms,
n1 is the average number of added moles of alkylene oxide and represents a number of 1 to 200;
When n1 is 2 or more, A ₁ O represents an alkyleneoxy group which may be the same or different. )
_{R 3 [-O- (A 2 O} ) n2 -R 4] m (3)
(In the formula,
R ₃ represents a residue obtained by removing m hydroxy groups from an m-valent polyhydric alcohol having 2 to 30 carbon atoms,
R ₄ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 22 carbon atoms and optionally containing an unsaturated bond,
A ₂ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms,
n2 is the average number of moles of alkylene oxide added and represents a number of 1 to 200;
When n2 is 2 or more, A ₂ O represents the same or different alkyleneoxy groups,
m represents an integer of 2 to 8. ) The admixture for geopolymers according to any one of claims 1 to 3, wherein the ether compound includes one or more compounds represented by the following general formula (4).
_{R 5 -O- (A 3 O)} n3 -R 6 (4)
(In the formula,
R ₅ is a hydrogen atom, a linear primary alkyl group having 1 to 22 carbon atoms, a branched primary alkyl group having 3 to 22 carbon atoms, or a tertiary alkyl group having 4 to 22 carbon atoms Represents a linear alkenyl group having 2 to 22 carbon atoms, a branched alkenyl group having 3 to 22 carbon atoms, a (meth) acryloyl group, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms,
R ₆ is a hydrogen atom, a straight chain alkyl group having 1 to 22 carbon atoms, a branched chain alkyl group having 3 to 22 carbon atoms, a straight chain alkenyl group having 2 to 22 carbon atoms, or a branched chain having 3 to 22 carbon atoms. Represents a chain alkenyl group, a (meth) acryloyl group, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms,
A ₃ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms, n3 represents the average number of moles of added alkylene oxide and represents 1 to 200, and (A ₃ O) _n3 represents the same alkylene. Represents n3 consecutive chains of oxide. ) In the above formula (4),
R ₅ is a hydrogen atom, a linear primary alkyl group having 1 to 12 carbon atoms, a branched primary alkyl group having 3 to 12 carbon atoms, or a tertiary alkyl group having 4 to 12 carbon atoms Represents a linear alkenyl group having 2 to 4 carbon atoms, a branched alkenyl group having 3 to 4 carbon atoms, or a phenyl group,
R ₆ represents a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms,
A ₃ O represents a divalent alkylene oxide group having 2 or 3 carbon atoms, and n3 represents a number of 1 to 100,
The admixture for geopolymers according to claim 4. The admixture for geopolymers according to any one of claims 1 to 5, wherein the ether compound is a compound having a weight average molecular weight (Mw) of 100 to 10,000. The shrinkage reducing agent is at least selected from the group consisting of at least one aluminosilicate source having a CaO content of 1 to 60% by mass, and an alkali metal hydroxide, an alkali metal carbonate and an alkali metal silicate. The admixture for geopolymer according to any one of claims 1 to 6, which is an additive for a geopolymer formed from a mixture containing one kind of alkali source. An admixture for a geopolymer according to any one of claims 1 to 7,
At least one aluminosilicate source having a CaO content of 1 to 60% by mass,
A geopolymer-forming composition comprising an aggregate and at least one alkali source selected from the group consisting of alkali metal hydroxides, alkali metal carbonates and alkali metal silicates. An admixture for a geopolymer according to any one of claims 1 to 7,
At least one aluminosilicate source having a CaO content of 1 to 60% by mass,
A cured geopolymer containing an aggregate and at least one alkali source selected from the group consisting of alkali metal hydroxides, alkali metal carbonates and alkali metal silicates.