JP6695548B2 - Shrinkage reducer for geopolymer and cured geopolymer - Google Patents

Description

  The present invention relates to a shrink reducing agent for a geopolymer, a geopolymer forming composition containing the shrink reducing agent, and a cured product thereof. More specifically, it relates to a shrinkage-reducing agent for a geopolymer, which suppresses the dry shrinkage of the 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 used 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 the pot life is secured, the strength development is poor (for example, Non-Patent Document 2 and Non-Patent Document 3). On the other hand, GP using BFS having 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 10 to 40 minutes, which is extremely short 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 cured in air because it may cause a decrease in alkali source concentration and exudation, but strain due to drying shrinkage of GP concrete demolded after curing in air (normal temperature) for 7 days (hereinafter, It has been found that the dry shrinkage strain) is much larger than that of conventional cement concrete (about 3 to 4 times), and is an issue that cannot be overlooked when aiming for 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, use of a shrinkage-reducing agent containing an ester compound having one or more specific structures for a geopolymer, in a particularly preferred embodiment, one or more aliphatic oxycarboxylic acid-based compounds By using the shrinkage-reducing agent for a geopolymer in the form of an admixture containing a shrinkage-reducing aid made of a compound, drying shrinkage is suppressed, and shrinkage strain in a cured product is significantly reduced, and strength is expressed. It has been found that workability can be secured without impairing the property, and further, generation of darkening and white sinter on the surface of the cured body can be suppressed, and a surface aesthetic effect can also be obtained.

That is, the present invention relates to a shrinkage-reducing agent for a geopolymer, which comprises one or more compounds (I) to (IV) represented by the following general formulas (1) to (4).
・ Compound (I)
^{R 1 -C (= O) -O-} (A 1 O) n1 -R 2 (1)
(In the formula,
R ¹ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 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;
R ² represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms or a —C (═O) —R ³ group,
R ³ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms. )
・ Compound (II)
^{_{[HO-C (= O)}} -] k R 4 [-C (= O) -O- (A 2 O) n2 -R 5] m
(2)
(In the formula,
R ⁴ represents a residue obtained by removing (k + m) carboxyl groups from a (k + m) -valent polycarboxylic acid having 1 to 30 carbon atoms, or a single bond,
k and m represent an integer satisfying the relationship of 0 ≦ k ≦ 5, 1 ≦ m ≦ 6, 2 ≦ k + m ≦ 6, and 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;
R ⁵ represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms. )
・ Compound (III)
_{^{[R 7 - (OA 3)}} n3 -O-] p R 6 [-O-C (= O) -R 8] q (3)
(In the formula,
R ⁶ represents a residue obtained by removing (p + q) hydroxy groups from a (p + q) polyhydric alcohol having 2 to 30 carbon atoms,
R ⁷ represents a hydrogen atom or a —O—C (═O) —R ⁹ group,
OA ³ represents a divalent oxyalkylene group having 2 to 4 carbon atoms,
n3 is the average number of moles of oxyalkylene added and represents a number of 1 to 200;
R ⁸ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms,
R ⁹ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms,
p and q represent integers that satisfy the relationship of 1 ≦ p ≦ 7, 1 ≦ q ≦ 7, and 2 ≦ p + q ≦ 8. )
・ Compound (IV)
_{^{[H- (OA 4) n4 -O-}} ] r R 10 [-O- (A 5 O) n5 -C (= O) -R 11] s (4)
(In the formula,
R ¹⁰ represents a residue obtained by removing (r + s) hydroxy groups from a (r + s) -valent polyhydric alcohol having 2 to 30 carbon atoms,
OA ⁴ represents a divalent oxyalkylene group having 2 to ⁴ carbon atoms,
n4 is the average number of moles of oxyalkylene added and represents a number of 1 to 200;
R ¹¹ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms,
A ⁵ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms,
n5 is the average number of moles of added alkylene oxide and represents a number of 1 to 200;
r and s represent integers that satisfy the relationship of 0 ≦ r ≦ 7, 1 ≦ s ≦ 8, and 2 ≦ r + s ≦ 8. )

  The shrinkage reducing agent for geopolymers of the present invention is a 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. It is preferably an additive applied to a geopolymer formed from a mixture containing at least one alkali source selected from

  Furthermore, the present invention comprises the shrink reducing agent for geopolymers and a salt of one or more aliphatic oxycarboxylic acids having a hydroxyl value of 250 to 1500 mgKOH / g and an acid value of 250 to 950 mgKOH / g, Also included are geopolymer admixtures that include a geopolymer shrinkage reduction aid having a mass weighted average hydroxyl group / acid value of the group oxycarboxylic acid of 0.40 or more and less than 5.00. Among them, the shrinkage-reducing auxiliary agent is one containing at least one salt of an aliphatic oxycarboxylic acid selected from the group consisting of lactate, malate, and tartrate, and particularly the shrinkage-reducing auxiliary agent is tartrate. It is preferable that it contains.

Further, the present invention provides the group consisting of the shrink reducing agent 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 alkalinity source selected from and an aggregate.
Furthermore, it is selected from 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. The present invention relates to a cured geopolymer containing at least one alkali source and an aggregate.

  The shrinkage-reducing agent for geopolymers of the present invention is excellent in the shrinkage-reducing effect in the geopolymers containing the same, and further, the workability before curing is improved by extending the setting time without impairing the strength development of the cured product, At the same time, it is possible to obtain a geopolymer cured product which enhances 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 present inventors have confirmed that the dry shrinkage strain of GP concrete is much larger 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 mention of ester compounds to which an oxyalkylene group is added.
In the present invention, the shrinkage reducing agent containing a specific ester compound is a particularly preferable embodiment in which a shrinkage reducing auxiliary agent containing a specific aliphatic oxycarboxylic acid compound is further contained. It has been found that while suppressing the drying shrinkage that is considered to occur, it achieves both workability assurance before curing and strength development of the cured product, and that the cured product has a good appearance. ..
Hereinafter, the present invention will be described in detail.

[Shrinkage reducer for geopolymer]
The shrinkage reducing agent for geopolymers of the present invention comprises an ester compound having a specific structure containing an oxyalkylene group (alkylene oxide group), and is specifically represented by the following general formula (1) to general formula (4). The compound (I) to the compound (IV) include one or more kinds.
The weight average molecular weights (Mw) of the following compounds (I) to (IV) used as the shrinkage reducing agent for geopolymers of the present invention are not particularly limited, but compounds having Mw of 100 to 10,000 are preferable, Further, a compound having Mw of 100 to 5,000 is preferable. In addition, in this specification, a weight average molecular weight (Mw) says the value measured by polystyrene conversion by gel permeation chromatography (GPC).

<< Compound (I) >>
^{R 1 -C (= O) -O-} (A 1 O) n1 -R 2 (1)
In the above general formula (1),
R ¹ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 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;
R ² represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms or a —C (═O) —R ³ group,
R ³ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms.

<< Compound (II) >>
^{_{[HO-C (= O)}} -] k R 4 [-C (= O) -O- (A 2 O) n2 -R 5] m
(2)
In the above general formula (2),
R ⁴ represents a residue obtained by removing (k + m) carboxyl groups from a (k + m) -valent polycarboxylic acid having 1 to 30 carbon atoms, or a single bond,
k and m represent an integer satisfying the relationship of 0 ≦ k ≦ 5, 1 ≦ m ≦ 6, 2 ≦ k + m ≦ 6, and 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;
R ⁵ represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms.

<< Compound (III) >>
^{_{[R 7 - (OA 3)}} n3 -O-] p R 6 [-O-C (= O) -R 8] q (3)
In the above general formula (3),
R ⁶ represents a residue obtained by removing (p + q) hydroxy groups from a (p + q) polyhydric alcohol having 2 to 30 carbon atoms,
R ⁷ represents a hydrogen atom or a —O—C (═O) —R ⁹ group,
OA ³ represents a divalent oxyalkylene group having 2 to 4 carbon atoms,
n3 is the average number of moles of oxyalkylene added and represents a number of 1 to 200;
R ⁸ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms,
R ⁹ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms,
p and q represent integers that satisfy the relationship of 1 ≦ p ≦ 7, 1 ≦ q ≦ 7, and 2 ≦ p + q ≦ 8.

<< Compound (IV) >>
_{^{[H- (OA 4) n4 -O-}} ] r R 10 [-O- (A 5 O) n5 -C (= O) -R 11] s (4)
In the above general formula (4),
R ¹⁰ represents a residue obtained by removing (r + s) hydroxy groups from a (r + s) -valent polyhydric alcohol having 2 to 30 carbon atoms,
OA ⁴ represents a divalent oxyalkylene group having 2 to ⁴ carbon atoms,
n4 is the average number of moles of oxyalkylene added and represents a number of 1 to 200;
R ¹¹ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms,
A ⁵ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms,
n5 is the average number of moles of added alkylene oxide and represents a number of 1 to 200;
r and s represent integers that satisfy the relationship of 0 ≦ r ≦ 7, 1 ≦ s ≦ 8, and 2 ≦ r + s ≦ 8.

In the above formula, the alkyl group having 1 to 30 carbon atoms in R ¹ , R ² , R ³ , R ⁵ , R ⁸ , R ⁹ , and R ¹¹ is a methyl group, an ethyl group, a propyl group, a butyl group, pentyl. Group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, heneicosyl group, Examples include docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, triacontyl group, and alkyl groups having 3 or more carbon atoms (that is, excluding the above-mentioned methyl group and ethyl group). , Propyl group), branched chains, cyclic groups It may include chains.
Further, the alkenyl group having 2 to 30 carbon atoms in R ¹ , R ² , R ³ , R ⁵ , R ⁸ , R ⁹ , and R ¹¹ includes an ethanyl group, a propanyl group, a butanyl group, a pentanyl group, a hexanyl group, and heptanyl. Group, octanyl group, nonanyl group, decanyl group, undecanyl group, dodecanyl group, tridecanyl group, tetradecanyl group, pentadecanyl group, hexadecanyl group, heptadecanyl group, octadecanyl group, nonadecanyl group, eicosanyl group, heneicosanyl group, docosanyl group, tricosanyl group, Examples thereof include a tetracosanyl group, a pentacosanyl group, a hexacosanyl group, a heptacosanyl group, an octacosanyl group, a nonacosanyl group, and a triacontanyl group, and an alkenyl group having 3 or more carbon atoms (that is, excluding the above-mentioned ethanyl group, a propanyl group or later). The group described in 1) may contain a branched chain or a cyclic chain.

Examples of the divalent alkylene oxide group having 2 to 4 carbon atoms in A ¹ O, A ² O and A ⁵ O include ethylene oxide group, propylene oxide group and butylene oxide group.
Examples of the divalent oxyalkylene group having 2 to ⁴ carbon atoms in OA ³ and OA ⁴ include an oxyethylene group, an oxypropylene group, and an oxybutylene group.
When n1, n2, and n5 are 2 or more, A ¹ O, A ² O, and A ⁵ O are each composed of the same kind of alkylene oxide group, but are also composed of two or more kinds of alkylene oxide groups. In the latter case, different types of alkylene oxide groups may be block addition or random addition.
When n3 and n4 are 2 or more, OA ³ and OA ⁴ may be composed of the same kind of oxyalkylene groups or may be composed of two or more kinds of oxyalkylene groups. The oxyalkylene groups different from each other may be block addition or random addition.

Further, the (k + m) -valent polycarboxylic acid having 1 to 30 carbon atoms in R ⁴ includes a linear polycarboxylic acid, and when it has 2 or more carbon atoms, contains an unsaturated double bond. May be present, and a plurality of carboxyl groups may be bonded to the same carbon atom, and when the number of carbon atoms is 3 or more, it represents a polyvalent carboxylic acid which may include a branched chain or a cyclic chain. In the present specification, the carbon atom of the carboxyl group (—COOH) is not included in the above number of carbon atoms).
The (k + m) -valent polycarboxylic acid is specifically a compound having 2 to 6 carboxyl groups, and is an aliphatic polycarboxylic acid (malonic acid, succinic acid, adipic acid, sebacic acid, maleic acid). , Fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, glutaric acid, azelaic acid); aromatic polycarboxylic acids (terephthalic acid, isophthalic acid, orthophthalic acid, trimellitic acid, pyromellitic acid); alicyclic polycarboxylic acids (Cyclohexane 1,4-dicarboxylic acid and the like). When R ⁴ is a single bond, oxalic acid can be mentioned. Of these, aliphatic polycarboxylic acids having 2 to 12 carbon atoms are more preferable, and succinic acid, adipic acid, sebacic acid, maleic acid, and fumaric acid are more preferable.
In R ⁴ , examples of the residue obtained by removing a (k + m) carboxyl group from a polyvalent carboxylic acid having 1 to 30 carbon atoms include a (k + m) valent hydrocarbon group having 1 to 30 carbon atoms. Be done.

Furthermore, the polyhydric alcohol having 2 to 30 carbon atoms (p + q valence) in R ^{6 and} the polyhydric alcohol having 2 to 30 carbon atoms (r + s valence) in R ¹⁰ are linear polyhydric alcohols, Further, it may contain an unsaturated double bond, a plurality of hydroxy groups may be bonded to the same carbon atom, and if it has 3 or more carbon atoms, it may contain a branched chain or a cyclic chain. , And polyhydric alcohol, respectively.
The (p + q) -valent polyhydric alcohol and the (r + s) -valent polyhydric alcohol are specifically compounds having 2 to 8 hydroxy groups, and examples thereof include dihydric alcohols (ethylene glycol, diethylene glycol, propylene glycol). , Butanediol, neopentyl glycol and hexanediol); polyhydric alcohols having 3 to 5 valences (glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitan and diglycerin); sugars and their derivatives (sucrose, glucose, Fructose and methyl glycoside etc.). Of these, polyhydric alcohols having 3 to 5 valences and sugars are preferably used, and more preferably sorbitol, sorbitan, polyglycerin, pentaerythritol, dipentaerythritol and sucrose.
Further, a residue obtained by removing (p + q) hydroxy groups from a polyhydric alcohol having 2 to 30 carbon atoms in R ⁷ and a (r + s) hydroxy group from a polyhydric alcohol having 2 to 30 carbon atoms in R ¹⁰ Examples of the removed residue include a (p + q) -valent hydrocarbon group having 2 to 30 carbon atoms and a (r + s) -valent hydrocarbon group having 2 to 30 carbon atoms. These hydrocarbon groups are ether bonds. May be included.

As the (k + m) -valent hydrocarbon group having 1 to 30 carbon atoms, the (p + q) -valent hydrocarbon group having 2 to 30 carbon atoms, and the (r + s) -valent hydrocarbon group having 2 to 30 carbon atoms Is not particularly limited, but includes, for example, an alkane having 1 to 30 carbon atoms or 2 to 30 carbon atoms, an alkene having 2 to 30 carbon atoms, and the like (k + m) hydrogen atoms, (p + q) hydrogen atoms, ( Examples thereof include groups excluding r + s).
Examples of the alkane having 1 to 30 carbon atoms include methane, 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.

In a preferred embodiment of the compound (I), R ¹ is an alkyl group having 1 to 18 carbon atoms and an alkenyl group having 2 to 18 carbon atoms (these are straight chain, branched chain, or cyclic chain, or a combination thereof). R ² is a hydrogen atom, an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 18 carbon atoms (these are a straight chain, a branched chain, or a cyclic chain, or a group thereof). A combination thereof may be included), a —C (═O) —R ³ group is included, and R ³ is an alkyl group having 1 to 18 carbon atoms (straight chain, branched chain, or cyclic chain, or a combination thereof). A combination may be included).
In a preferred embodiment, A ¹ O includes an ethylene oxide group and a propylene oxide group.
n1 represents a number of 1 to 100 in a preferred embodiment, and represents a number of 1 to 50 in a more preferred embodiment.

The compound (II) is a compound having a structure in which a part or all of the carboxyl groups of the polyvalent carboxylic acid described later are reacted with the polyoxyalkylene compound.
In a preferred embodiment of compound (II), R ⁴ is a residue obtained by removing (k + m) carboxyl groups from a (k + m) -valent polycarboxylic acid having 2 to 10 carbon atoms, that is, the above-mentioned residue is Include a (k + m) -valent hydrocarbon group having 2 to 10 carbon atoms (which may include a straight chain, a branched chain, a cyclic chain, or a combination thereof).
R ⁵ in a preferred embodiment represents an alkyl group having 1 to 10 carbon atoms (which may include a linear chain, a branched chain, a cyclic chain, or a combination thereof).
In a preferred embodiment, A ² O includes ethylene oxide group and propylene oxide group.
n2 represents a number of 1 to 100 in a preferred embodiment, and represents a number of 1 to 50 in a more preferred embodiment.
And k represents 0 or 1 in a preferred embodiment, and m represents 1 or 2 in a preferred embodiment.

In a preferred embodiment of compound (III), R ⁶ is a residue obtained by removing (p + q) hydroxy groups from a (p + q) polyhydric alcohol having 2 to 10 carbon atoms, that is, the residue is , A (p + q) -valent hydrocarbon group having 2 to 10 carbon atoms (these may include a straight chain, a branched chain, a cyclic chain, or a combination thereof, and the hydrocarbon group contains an ether bond. Can be).
And p and q represent the integer which satisfy | fills the relationship of 1 <= p <= 4, 1 <= q <= 4, 2 <= p + q <= 6 in a preferable aspect.
R ⁷ represents a hydrogen atom in a preferred embodiment.
In a preferred embodiment, R ⁸ is an alkyl group having 1 to 18 carbon atoms and an alkenyl group having 2 to 18 carbon atoms (these may include a straight chain, a branched chain, or a cyclic chain, or a combination thereof. ) Are mentioned, and in a particularly preferable embodiment, an alkyl group or an alkenyl group having 10 to 18 carbon atoms can be mentioned.
In a preferred embodiment, OA ³ includes an oxyethylene group and an oxypropylene group.
n3 represents a number of 1 to 100 in a preferable embodiment, and 1 to 80, for example, 5 to 80 in a more preferable embodiment.

In a preferred embodiment of compound (IV), R ¹⁰ includes a residue obtained by removing (r + s) hydroxy groups from a (r + s) -valent polyhydric alcohol having 2 to ¹⁰ carbon atoms, that is, the residue is A (r + s) -valent hydrocarbon group having 2 to 10 carbon atoms (these may include a straight chain, a branched chain, a cyclic chain, or a combination thereof, and the hydrocarbon group contains an ether bond. May be used).
Further, r and s represent integers that satisfy the relationship of 1 ≦ r ≦ 4, 1 ≦ s ≦ 4, and 2 ≦ r + s ≦ 6 in a preferred embodiment.
In a preferred embodiment, R ¹¹ is an alkyl group having 1 to 18 carbon atoms and an alkenyl group having 2 to 18 carbon atoms (these may include a straight chain, a branched chain, or a cyclic chain, or a combination thereof. ) Are mentioned, and in a particularly preferable embodiment, an alkyl group or an alkenyl group having 10 to 18 carbon atoms can be mentioned.
In a preferred embodiment, OA ⁴ includes an oxyethylene group and an oxypropylene group, and n4 represents a number of 1 to 100 in a preferred embodiment, and a number of 1 to 80 in a more preferred embodiment.
In a preferred embodiment, A ⁵ O includes an ethylene oxide group and a propylene oxide group, and n5 represents a number of 1 to 100 in a preferred embodiment, and a number of 1 to 80 in a more preferred embodiment.
Note that, for example, in a preferred embodiment, n4 + n5 represents a number of 20 to 80.

In the shrinkage reducing agent for geopolymers of the present invention, commercially available compounds may be used as the compounds (I) to (IV) represented by the general formulas (1) to (4).
In the compound (III) represented by the general formula (3), a part of the hydroxy groups in the polyhydric alcohol is a carboxylic acid represented by the formula R ⁸ —COOH (R ⁸ has the same meaning as defined above. It can be produced by further adding an alkylene oxide having 2 to 4 carbon atoms after esterification (see, for example, Japanese Patent No. 3840654).
Further, the compound (IV) represented by the general formula (4) is obtained by adding an alkylene oxide having 2 to 4 carbon atoms to a polyhydric alcohol, and then adding a compound of the formula (4) to the active hydrogen atom of the obtained compound. It can be produced by reacting a carboxylic acid represented by R ¹¹ —COOH (R ¹¹ represents the meaning as defined above) and esterifying (see, for example, JP-A-4-240266).

The shrinkage reducing agent for geopolymers of the present invention may further contain compounds other than the compounds (I) to (IV) represented by the general formulas (1) to (4). The compound is not particularly limited as long as it is a compound having high compatibility with the compounds (I) to (IV), and examples thereof include ether compounds represented by the following general formula (6). .. The weight average molecular weight (Mw) of the ether compound represented by the following general formula (6) is not particularly limited, but examples thereof include compounds having Mw of 100 to 10,000, and Mw of 100 to 5,000. Compounds are preferred.
《Ether compound》
_{^{R 12 -O- (A 6 O)}} n6 -R 13 (6)
In the general formula (6), R ¹² and R ¹³ are each independently a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, a (meth) acryloyl group, or It represents a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms.
A 6 ^O represents a divalent alkylene oxide group having 2 to 4 carbon atoms, n6 is a number from 1 to 200 an average molar number of addition of alkylene oxide.

In R ¹² and R ¹³ , the alkyl group having 1 to 30 carbon atoms and the alkenyl group having 2 to 30 carbon atoms include the groups mentioned in the definition of the groups in the general formulas (1) to (4). Can be 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 monovalent hydrocarbon groups having 1 to 22 carbon atoms (groups having 1 to 22 carbon atoms among the alkyl groups and alkenyl groups exemplified for R ¹ and the like).
In addition, examples of the divalent alkylene oxide group having 2 to 4 carbon atoms in A ⁶ O include an ethylene oxide group, a propylene oxide group, and a butylene oxide group (note that they are OA (oxyalkylene groups) due to the bond structure). In some cases, including oxyethylene group, oxypropylene group, oxybutylene group). When n6 is 2 or more, A ⁶ O may be composed of the same kind of alkylene oxide group or may be composed of two or more kinds of alkylene oxide groups, and in the latter case, different kinds of alkylene oxide groups. May be block addition or random addition.

In a preferred embodiment, R ¹² and R ¹³ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms.
Further, in a preferred embodiment, A ⁶ O represents an ethylene oxide group or a propylene oxide group, and n6 represents a number of 1 to 20.

  In the shrinkage reducing agent for geopolymers of the present invention, the compounds (I) to (IV) represented by the general formulas (1) to (4) and the ether compound represented by the general formula (6). The compounding amount of compound (I) to compound (IV): total amount of ether compound = 100 mass% to 10 mass%: 0 mass% to 90 mass%, and in a preferred embodiment, the same = 100 mass%. -30% by mass: 0% by mass to 70% by mass.

[Admixture for geopolymer]
The shrinkage-reducing agent for geopolymers of the present invention can be combined with a shrinkage-reducing auxiliary agent for geopolymers to form an admixture for geopolymers.
The shrinkage-reducing aid used in the admixture for geopolymers of the present invention can be used without particular limitation as long as it has a function of further increasing the shrinkage-reducing effect of the shrinkage-reducing agent of the present invention. Additives that exert a setting retarding effect can be used.

In the admixture for a geopolymer of the present invention, the mixing ratio of the shrinkage reducing agent and the shrinkage reducing auxiliary agent is not particularly limited, but for example, the shrinkage reducing agent and: shrinkage reducing auxiliary agent = 10: 1 to 1:10 (mass Ratio), preferably (the same), 5: 1 to 1: 5.
The admixture for geopolymer of the present invention is a form containing the shrinkage-reducing agent and the shrinkage-reducing auxiliary agent of the present invention, a form in which a known admixture other than the shrinkage-reducing agent and the shrinkage-reducing auxiliary agent of the present invention is blended, and the geopolymer ( (Cured product) At the time of production, the shrinkage-reducing agent and the shrinkage-reducing aid in the admixture for geopolymer of the present invention are added separately (or at least two kinds in combination), and finally the geopolymer is added. Including any of the forms mixed therein.

[Shrinkage reduction aid for geopolymers]
The shrinkage-reducing auxiliary agent to be blended in the admixture for geopolymer of the present invention is not particularly limited as described above, but in the present invention, as a preferable shrinkage-reducing auxiliary agent, the shrinkage-reducing effect can be further enhanced. It is preferable to use a salt of at least one aliphatic oxycarboxylic acid having a specific hydroxyl value and acid value, and a specific hydroxyl value / acid value.
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, and preferably sodium salt.

[Geopolymer-forming composition / geopolymer]
Geopolymer applying the shrinkage reducing agent of the present invention, and the admixture containing the shrinkage reducing agent and the shrinkage reducing auxiliary agent, as described above, an aluminosilicate source such as an active filler, an alkali source such as an alkali silica solution, And a mixture containing aggregate and the like.
The present invention is directed to the shrinkage reducing agent for geopolymer (or admixture for geopolymer), an aluminosilicate source such as the active filler constituting the geopolymer, an alkali source such as an alkali silica solution, and an aggregate described later. Also included are geopolymer-forming compositions that include and geopolymer cured products that are cured products of the geopolymer-forming composition.

The geopolymer to which the shrinkage reducing agent for geopolymer of the present invention (or the admixture for geopolymer) is applied is supposed to contain at least one kind of various active fillers described below as an aluminosilicate source as an essential component, and an alkali It is assumed that the source contains so-called water glass described later.
The geopolymer targeted by the shrinkage-reducing agent (or admixture for geopolymer) of the present invention is, for example, 0 to 100% by mass of fly ash and 100 to 0% by mass of blast furnace slag fine powder as an aminosilicate source ( 100% by mass in total), preferably at least one aluminosilicate source having a CaO content of 1 to 60% by mass, an alkali metal hydroxide, an alkali metal carbonate and It is possible to use an object constituted by including at least one alkali source selected from the group consisting of alkali metal silicates.

<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. Examples of the aluminosilicate source having a relatively high CaO content of 10 to 60 mass% include, for example, blast furnace slag fine powder, municipal solid waste incineration ash slag fine powder, sewage sludge incineration ash slag fine powder, and CaO-rich fluidized bed coal ash. Etc. 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 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 generated 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 to burn coal for the purpose of desulfurization in the furnace, it is characterized by containing more CaO than fly ash and clinker ash described later. Fluidized bed coal ash does not satisfy the current JIS standard (JIS A 6201) of fly ash for concrete admixture, but 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 dewatering, namely, lime-based incineration ash with slaked lime and ferric chloride added, and polymer-based incineration ash with polymer coagulant added. .. 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 made of 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 shrinkage reducing agent for geopolymer (or admixture for geopolymer) of the present invention is applied has the above CaO content of 1 to 60. A comparison of at least one aluminosilicate source that is mass%, specifically, blast furnace slag fine powder, municipal solid waste incineration ash slag fine powder, sewage sludge incineration ash molten slag fine powder, fluid bed coal ash (rich in CaO), etc. At least one of an aluminosilicate source having a high CaO content and an aluminosilicate source having a low CaO content such as fly ash and clinker ash is included 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 an aluminosilicate source and mixed, and further an aggregate is added and mixed, and a shrinkage reducing agent of the present invention (or an admixture for geopolymer) is added as described later, A geopolymer forming composition is prepared.
Incidentally, the present invention, the above-mentioned admixture for geopolymer containing the shrinkage-reducing agent and the shrinkage-reducing aid, at least one aluminosilicate source having a CaO content of 1 to 60% by mass, an alkali metal hydroxide, an alkali metal. Also contemplated are hardened geopolymers that include an aggregate and at least one alkali source selected from the group consisting of carbonates and alkali metal silicates.

  As the aggregate, those generally used in concrete or mortar (fine aggregate, coarse aggregate, etc.) can be preferably used.

The shrinkage reducing agent for geopolymers (or admixtures for geopolymers) of the present invention may be added together when preparing the alkali source, or after kneading the alkali source, the aluminosilicate source and the aggregate. You may add and mix uniformly. Further, it is possible to use the shrinkage reducing agent for geopolymer (or the admixture for geopolymer) as an aqueous solution or as a solid. It is also possible to produce a geopolymer-forming composition using a mixture of an aluminosilicate source and an aqueous solution of a shrinkage-reducing agent for geopolymer (or an admixture for geopolymer) and / or a shrinkage-reducing agent (or admixture). It is possible.
As described above, the shrinkage reducing agent for geopolymer (or the admixture for geopolymer) can be mixed with either the aluminosilicate source or the alkali source and further mixed with the remaining materials used for the geopolymer, even if the premixed alumino It may be added to the mixture of the silicate source and the alkali source, but 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, when the shrinkage-reducing auxiliary agent is included (in the case of an admixture), the shrinkage-reducing auxiliary agent and other admixture components may be added after the shrinkage-reducing agent is first added and kneaded.
Regarding the blending design of the geopolymer, the ratio of the total mass of the alkali solution (alkali source: water glass + sodium hydroxide hydroxide + water) and the total mass of the aluminosilicate source (active filler powder (B)) ([alkali 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 shrinkage-reducing agent for geopolymer may be variously changed depending on the configuration of the shrinkage-reducing agent and the configuration of the geopolymer-forming composition (material used for the geopolymer) (for example, the configuration of the aluminosilicate source). Can be added in an amount of 1 to 30% by mass, for example 5 to 20% by mass, based on the mass of the aluminosilicate source. Further, the blending ratio of the admixture for a geopolymer can be appropriately set within the above numerical range.

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

[Shrinkage reducing agent for geopolymer: Preparation of ester compound]
Tables 1 and 2 show compounds (ester compounds and ether compounds) X1 to X13 used as shrinkage reducing agents in Examples and shrinkage reducing agents Y2 to Y4 for comparison.
Among the shrinkage-reducing agents used in Comparative Examples, Y4 is the shrinkage-reducing agent disclosed in the examples (Examples) of Japanese Patent No. 4677181.
In the examples and comparative examples described below, the shrinkage-reducing auxiliary agent A1 described below is mixed in a mass ratio of 1: 1 with respect to the following X1 to X13 and Y2 to Y4, and the mixture is an admixture. Used as.

[Shrinkage reduction aid for geopolymers]
As an oxycarboxylic acid compound, L-tartaric acid (molecular formula: C4H6O6, acid value: 748, hydroxyl value: 748, hydroxyl value / acid value: 1.00), 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, and is a shrinkage-reducing auxiliary agent for geopolymer by neutralization reaction. Sodium tartrate (30% aqueous solution) was prepared. The molar ratio of L-tartaric acid (acid) and sodium hydroxide (alkali) was 1: 1. Then, an aqueous solution of the shrinkage-reducing auxiliary agent for geopolymer was heated, concentrated, recrystallized, and fractionated to obtain a solid shrinkage-reducing auxiliary agent for sodium (sodium tartrate) (A1). 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 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) were mixed according to the unit amount (g) of Table 3 and Table 6. No. Each alkaline solution (GP solution) shown in 1-3 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 activity shown in Tables 3 and 6 for the 1: 1 mixture (mass ratio) of the shrinkage reducing agents indicated by X1 to X12 and Y2 to Y4 in Tables 1 and 2 and the shrinkage reducing auxiliary agent A1 (sodium tartrate). It was added at a ratio of 3% by mass, 5% by mass or 7% by mass (solid content conversion) with respect to the mass (g) of the filler B or the mass (g) of the fine powder of molten slag molten slag WS of municipal waste. In addition, the alkaline solution / B (fly ash + blast furnace slag fine powder) or alkaline solution / WS (city waste incinerator ash molten slag fine powder) (all in mass ratio,%) shown in Tables 3 and 6 are the use of each component. It is a value calculated from the amount.

[Geopolymer mortar 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. Compound No. shown in Table 3 and Table 6. In Examples 1 to 3, the active filler used was JIS II class 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 and the shrinkage reducing agent for geopolymer prepared by the above procedure are weighed and mixed in proportions to predetermined active fillers, mixed and then added to the active fillers, and stirred at low speed (revolution 62 rpm, rotation 141 rpm) for 120 seconds. did.
After the completion of the low speed stirring, the operation of the mixer was stopped, and within 30 seconds after the operation was stopped, the mixer was mixed with the composition No. shown in Tables 3 and 6 as the fine aggregate (S). 1 to 3 (unit amount (g)) was added to the standard sand for cement strength test, and the mixture was again stirred at a low speed for 30 seconds, and then rapidly stirred at a 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 shrinkage strain and mass reduction rate>
Compound No. shown in Table 3 and Table 6. The geopolymer mortar prepared in 1 to 3 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 embedded strain gauge (KMC manufactured by Kyowa Denki Co., Ltd.) was placed at the center of the test piece. -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 air-cured for 28 days under the conditions of a temperature of 20 ° C. and a relative humidity of 60% (28 days old), and a data logger (NTB-100A-120) connected to an embedded strain gauge was used. Then, the change in length was measured to determine the shrinkage strain (μm / m).
In addition, No. In the formulations shown in 1 and 2, the total mass at the time of filling into the mold and the total mass at the end of the measurement of the above-mentioned length change after 28 days of curing in air were measured, and the total mass at the time of addition of the shrinkage reducing agent was not measured. Using the measured value in the case of addition, the mass reduction rate by using the shrinkage reducing agent was calculated by the following formula.

<Measurement of compressive strength and evaluation of surface appearance of cured geopolymer mortar>
In measuring the compressive strength of the geopolymer mortar cured product, the geopolymer mortar produced above was placed in the same plastic mold (φ5 cm, height 10 cm) used in the above <Measurement of shrinkage strain and mass reduction rate>. After filling, the upper surface was covered with a food wrap film (manufactured by Asahi Kasei Home Products 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. Then, 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.
The appearance (darkening) of the cured geopolymer mortar 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 darkening evaluation criteria x: Darkening is noticeably observed on the surface of the specimen (surface area 2% or more)
Δ: A slight darkening is observed on the surface of the test piece (approximately less than 2% surface area)
○: No darkening is observed on the surface of the specimen

  Performed on GP mortar prepared by using fly ash and blast furnace slag fine powder as active filler, the fluidity of mortar (mortar flow value), compressive strength, evaluation of surface appearance of cured product, shrinkage strain and mass reduction rate The test results are shown in Tables 4 and 5. In addition, the flowability (mortar flow value), the compression strength, the evaluation of the surface appearance of the cured product, and the test results of shrinkage strain performed on the GP mortar produced by using the municipal solid waste incinerated ash molten slag fine powder as the active filler are shown. 7 shows.

As described above, in the geopolymer, it is considered that the dry shrinkage due to the dissipation of water occurs from the setting stage, and enabling reduction of the dry shrinkage is one of the performances particularly important as the additive for the geopolymer. It becomes one.
From the test results (Examples 1 to 27) of the geopolymer mortars shown in Tables 4, 5 and 7, a comparative example in which the shrinkage reducing agent for geopolymers of the present invention was used and no shrinkage reducing agent was used ( As a result, the shrinkage strain of the geopolymer (cured product) was reduced by about 50% or more as compared with Comparative Examples 1, 5, 10). In the shrinkage-reducing agent of the present invention, when the total number of added alkyleneoxy groups in the compound used was small, the shrinkage-reducing effect tended to increase.
On the other hand, the comparative examples (Comparative Examples 2, 3, 4, 6, 7, 8, 9) using the shrinkage-reducing agents Y2 to Y4 using the ester-based compound to which the oxyalkylene group is not added have the shrinkage-reducing effect. The result was that it could not be obtained at all.

  Further, as shown in the above results, the geopolymer-forming composition (geopolymer mortar) containing the shrinkage-reducing agent for a geopolymer of the present invention containing a shrinkage-reducing agent for a geopolymer impairs strength development of a cured product. It was confirmed that it is possible to obtain a geopolymer (cured product) that ensures the fluidity of the geopolymer before curing and has an excellent surface appearance.

  By using the shrinkage reducing agent for geopolymers of the present invention, the shrinkage strain is greatly reduced in the geopolymer using a filler having a high CaO content (for example, blast furnace slag fine powder), It was confirmed that a strength-enhancing geopolymer cured product could be produced without lowering the strength development compared to the comparative example even when cured in air.

JP, 2014-28726, A JP, 2012-240852, A Patent No. 4677181 Japanese Patent Publication No. 2015-53624 International Publication No. 2010/130582

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Claims (7)

A shrinkage-reducing agent for a geopolymer, which comprises one or more compounds (I) to (IV) represented by the following general formulas (1) to (4).

^{R 1 -C (= O) -O-} (A 1 O) n1 -R 2 (1)
(In the formula,
R ¹ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 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;
R ² represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms or a —C (═O) —R ³ group,
R ³ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms. )

^{_{[HO-C (= O)}} -] k R 4 [-C (= O) -O- (A 2 O) n2 -R 5] m
(2)
(In the formula,
R ⁴ represents a residue obtained by removing (k + m) carboxyl groups from a (k + m) valent polycarboxylic acid having 1 to 30 carbon atoms, or a single bond,
k and m represent an integer satisfying the relationship of 0 ≦ k ≦ 5, 1 ≦ m ≦ 6, 2 ≦ k + m ≦ 6, and 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;
R ⁵ represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms. )

_{^{[R 7 - (OA 3)}} n3 -O-] p R 6 [-O-C (= O) -R 8] q (3)
(In the formula,
R ⁶ represents a residue obtained by removing (p + q) hydroxy groups from a (p + q) polyhydric alcohol having 2 to 30 carbon atoms,
R ⁷ represents a hydrogen atom or a —O—C (═O) —R ⁹ group,
OA ³ represents a divalent oxyalkylene group having 2 to 4 carbon atoms,
n3 is the average number of moles of oxyalkylene added and represents a number of 1 to 200;
R ⁸ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms,
R ⁹ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms,
p and q represent integers that satisfy the relationship of 1 ≦ p ≦ 7, 1 ≦ q ≦ 7, and 2 ≦ p + q ≦ 8. )

_{^{[H- (OA 4) n4 -O-}} ] r R 10 [-O- (A 5 O) n5 -C (= O) -R 11] s (4)
(In the formula,
R ¹⁰ represents a residue obtained by removing (r + s) hydroxy groups from a (r + s) -valent polyhydric alcohol having 2 to 30 carbon atoms,
OA ⁴ represents a divalent oxyalkylene group having 2 to ⁴ carbon atoms,
n4 is the average number of moles of oxyalkylene added and represents a number of 1 to 200;
R ¹¹ represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms,
A ⁵ O represents a divalent alkylene oxide group having 2 to 4 carbon atoms,
n5 is the average number of moles of added alkylene oxide and represents a number of 1 to 200;
r and s represent integers that satisfy the relationship of 0 ≦ r ≦ 7, 1 ≦ s ≦ 8, and 2 ≦ r + s ≦ 8. ) At least one aluminosilicate source having a CaO content of 1 to 60 mass% and at least one alkali source selected from the group consisting of alkali metal hydroxides, alkali metal carbonates and alkali metal silicates The shrink reducing agent for a geopolymer according to claim 1, which is an additive for a geopolymer formed from a mixture. A shrinkage reducing agent for a geopolymer according to claim 1 or 2,
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,
Admixture for geopolymer. The admixture for a geopolymer according to claim 3, wherein the shrinkage-reducing aid contains at least one salt of an aliphatic oxycarboxylic acid selected from the group consisting of lactate, malate and tartrate. The admixture for geopolymers according to claim 4, wherein the shrinkage reduction aid contains a tartrate salt. A shrinkage reducing agent for a geopolymer according to claim 1 or 2,
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 3 to 5,
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.