Geopolymer composition and geopolymer cured product

Abstract

To provide a geopolymer composition that can suppress drying shrinkage during curing while ensuring compressive strength after curing. [Solution] The geopolymer composition contains an active filler, water, an alkaline activator, and at least one chemical admixture selected from the group consisting of ester compounds having an oxyalkylene group, ether compounds having an oxyalkylene group, and glycol compounds having an oxyalkylene group, wherein the chemical admixture is at least one selected from the group consisting of a chemical (1) with a weight-average molecular weight of 300 to 1000 and an HLB value of 15 to 20, a chemical (2) with a weight-average molecular weight of 150 to 300 and an HLB value of less than 15 to 20, and a chemical (3) with a weight-average molecular weight of 150 to 300 and an HLB value of 10 to 15.

Description

[Technical Field]

[0001] This disclosure relates to geopolymer compositions and geopolymer cured products. [Background technology]

[0002] Patent Document 1 discloses a shrinkage-reducing agent for geopolymers comprising an ester compound having an oxyalkylene group.

[0003] Patent Document 2 discloses a geopolymer admixture containing a shrinkage reducing agent made of an oxyalkylene alkyl ether compound and a shrinkage reducing aid made of an aliphatic oxycarboxylate salt.

[0004] Patent Document 3 discloses a shrinkage-reducing agent for geopolymers comprising a glycol ether compound.

[0005] Patent Document 4 discloses a geopolymer composition comprising an activated filler containing fly ash and blast furnace slag, an alkaline solution containing sodium silicate and / or sodium hydroxide, and a cement mineral-based expansive agent.

[0006] Patent Document 5 discloses a geopolymer composition containing an active filler, a base, water, and blast furnace slag fine aggregate.

[0007] Patent Document 6 discloses a geopolymer composition comprising an active filler, a base, water, blast furnace slag aggregate, and at least one selected from the group consisting of ester compounds having oxyalkylene groups, ether compounds having oxyalkylene groups, and glycol compounds having oxyalkylene groups.

[0008] Patent Document 7 discloses a geopolymer composition comprising an active filler, an alkaline solution containing a silicate, and a shrinkage-reducing agent. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2017-202963 [Patent Document 2] Japanese Patent Publication No. 2017-202964 [Patent Document 3] Japanese Patent Publication No. 2018-150195 [Patent Document 4] Japanese Patent Publication No. 2020-055696 [Patent Document 5] Japanese Patent Publication No. 2022-191946 [Patent Document 6] Japanese Patent Publication No. 2022-191947 [Patent Document 7] Japanese Patent Publication No. 2022-191948 [Overview of the project] [Problems that the invention aims to solve]

[0010] As disclosed in Patent Documents 1 to 3, various chemical admixtures have been developed for purposes such as suppressing drying shrinkage of hardened geopolymers. However, it is known that adding chemical admixtures that suppress drying shrinkage reduces the compressive strength of hardened geopolymers. Furthermore, it has been pointed out that the compressive strength of hardened geopolymers cured at room temperature is lower than that of hardened materials cured by air curing or drying curing compared to those cured by sealing (Hiroshi Kadota, Yosaku Ikeo: Drying shrinkage and adhesion strength of geopolymers using sodium carbonate, Proceedings of the Architectural Institute of Japan Annual Meeting (Kinki), September 2023. Hitoshi Kimura, Ryuhei Kobayashi, Ponmahsai Parami, Koji Harada, et al.: Basic research on shrinkage reduction of geopolymer concrete manufactured in a room temperature environment (Parts 1 to 3), Proceedings of the Architectural Institute of Japan Annual Meeting (Kanto), August 2024).

[0011] This disclosure was made under the circumstances described above. The object of this disclosure is to provide a geopolymer composition that can ensure compressive strength after curing while suppressing drying shrinkage during curing. [Means for solving the problem]

[0012] The following embodiments are included as specific means for solving the aforementioned problems. <1> Activated filler, Water and, Alkaline activators and, It contains at least one chemical admixture selected from the group consisting of ester compounds having an oxyalkylene group, ether compounds having an oxyalkylene group, and glycol compounds having an oxyalkylene group, The aforementioned chemical admixture A chemical substance with a weight-average molecular weight of 300-1000 and an HLB value of 15-20 (1), Chemicals (2) with a weight-average molecular weight of 150-300 and an HLB value of less than 15-20 It is at least one chemical substance selected from the group consisting of (3) chemical substances with a weight-average molecular weight of 150 to 300 and an HLB value of 10 to 15. Geopolymer composition. <2> The aforementioned chemical admixture Compounds (1a) with a weight-average molecular weight of 380-1000 and an HLB value of 18-20, and At least one compound selected from the group consisting of compounds (2a) having a weight-average molecular weight of 165-250 and an HLB value of 16-19. <1> The geopolymer composition described above. <3> The alkaline activator includes an alkali metal carbonate. <1> or <2> The geopolymer composition described above. <4> The total amount of the chemical admixture is 0.5% to 3% by mass relative to the total amount of the active filler. <1> ~ <3> A geopolymer composition as described in any one of the following. <5> <1> ~ <4> A geopolymer cured body, which is a cured product of any one of the geopolymer compositions described in any one of the above. [Effects of the Invention]

[0013] This disclosure provides a geopolymer composition that can ensure compressive strength after curing while suppressing drying shrinkage during curing. According to this disclosure, a geopolymer cured body is provided that exhibits a low degree of drying shrinkage and ensures compressive strength. [Brief explanation of the drawing]

[0014] [Figure 1] This is a scatter plot showing the weight-average molecular weight and HLB value of chemical admixtures. [Modes for carrying out the invention]

[0015] Embodiments of the invention are described below. These descriptions and embodiments are illustrative and do not limit the scope of the invention.

[0016] In this disclosure, the numerical range indicated using "~" includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced by the upper or lower limit of another numerical range described in stages. In numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced by the values ​​shown in the examples.

[0017] In this disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, provided that their objectives are achieved.

[0018] When referring to the amount of each component in a composition in this disclosure, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition.

[0019] <Geopolymer composition> The geopolymer composition of this disclosure is a composition in a state referred to as slurry, fresh, etc., and a cured geopolymer body of this disclosure is obtained by curing the geopolymer composition of this disclosure.

[0020] The geopolymer compositions disclosed herein are Activated filler, Water and, Alkaline activators and, It contains at least one chemical admixture selected from the group consisting of ester compounds having an oxyalkylene group, ether compounds having an oxyalkylene group, and glycol compounds having an oxyalkylene group, and at least one chemical admixture selected from the group consisting of the following chemicals (1), (2), and (3).

[0021] • Chemicals (1): Chemicals with a weight-average molecular weight of 300 or more and 1000 or less, and an HLB value of 15 or more and 20 or less. • Chemicals (2): Chemicals with a weight-average molecular weight of 150 or more and 300 or less, and an HLB value of 15 or more and less than 20. • Chemicals (3): Chemicals with a weight-average molecular weight of 150 or more and 300 or less, and an HLB value of 10 or more and 15 or less.

[0022] In this disclosure, ester compounds having an oxyalkylene group, ether compounds having an oxyalkylene group, and glycol compounds having an oxyalkylene group are collectively referred to as "chemical admixtures having an oxyalkylene group."

[0023] The HLB value (Hydrophile-Lipophile Balance Value) is an index that represents the properties of a surfactant, and it takes a value from 0 to 20. The closer to 0, the more easily it is attracted to oil (organic compounds insoluble in water) (i.e., it is lipophilic), and the closer to 20, the more easily it is attracted to water (i.e., it is hydrophilic).

[0024] In this disclosure, the HLB value of a chemical admixture having an oxyalkylene group is a value obtained from the following formula by the Griffin method. HLB = 20 × Sum of formula weights of the hydrophilic portion of the target compound ÷ Molecular weight of the target compound

[0025] The geopolymer composition of this disclosure contains a chemical admixture having at least one oxyalkylene group selected from the group consisting of chemical (1), chemical (2), and chemical (3), thereby ensuring compressive strength after curing while suppressing drying shrinkage during curing. Chemical compound (1) is a chemical admixture having an oxyalkylene group, the effectiveness of which has been confirmed by Examples 1 to 3 described later. Chemical compound (2) is a chemical admixture having an oxyalkylene group, the effectiveness of which has been confirmed by Examples 4-5 described later. Chemical compound (3) is a chemical admixture having an oxyalkylene group, the effectiveness of which has been confirmed by Examples 6 to 8 described later.

[0026] A preferred embodiment of the geopolymer composition of this disclosure contains a chemical admixture having at least one oxyalkylene group selected from the group consisting of the following chemicals (1a) and (2a).

[0027] • Compound (1a): A compound with a weight-average molecular weight of 380-1000 and an HLB value of 18-20. • Compound (2a): Compounds with a weight-average molecular weight of 165-250 and an HLB value of 16-19

[0028] The above embodiment is a more preferable form from the viewpoint of not reducing the compressive strength too much even when curing is performed without curing to prevent drying, and from the viewpoint of minimizing the impact on the appearance of the cured body. Chemical compound (1a) is a chemical admixture having an oxyalkylene group, the effectiveness of which has been confirmed by Examples 1 to 3 described later. Chemical compound (2a) is a chemical admixture having an oxyalkylene group, the effectiveness of which has been confirmed by Examples 4 and 5 described later.

[0029] Among the compounds (1a), at least one selected from the group consisting of compounds with a weight-average molecular weight of 380 to 420 and an HLB value of 18 to 20, and compounds with a weight-average molecular weight of 980 to 1000 and an HLB value of 19 to 20 is preferred.

[0030] The materials constituting the geopolymer composition of this disclosure will be described in detail below.

[0031] [Activated filler] Activated fillers are generally powders whose main component is aluminum silicate. Examples of active fillers include blast furnace slag powder, fly ash, metakaolin, silica fume, zeolite powder, molten slag powder from waste incineration ash, molten slag powder from sewage sludge, volcanic ash, rice husk ash, fluidized bed coal ash, paper mill sludge incineration ash, and mixtures of at least two of these.

[0032] Preferred forms of the active filler include at least one of blast furnace slag powder (BFS) and fly ash (FA). Geopolymer compositions containing BFS tend to have high compressive strength in the cured product. Geopolymer compositions containing FA tend to have excellent fluidity and workability.

[0033] A preferred form of the active filler is a mixture of blast furnace slag powder (BFS) and fly ash (FA). By mixing BFS and FA, a geopolymer composition and a geopolymer cured body with a good balance of fluidity, workability, and mechanical strength can be obtained. The mixing ratio of BFS to FA is not limited and should be selected according to the target fluidity, workability, pot life, setting time, pore structure, mechanical strength, etc. Examples of mass ratios of BFS to FA (BFS:FA) are 20:80 to 80:20, 30:70 to 70:30, and 40:60 to 60:40.

[0034] One example of an active filler embodiment includes only BFS and FA. In this embodiment, the mass ratio of BFS to FA (BFS:FA) is, for example, 20:80 to 80:20, 30:70 to 70:30, or 40:60 to 60:40.

[0035] The quality of BFS (e.g., density, specific surface area) and FA (e.g., density, specific surface area) is not limited and should be selected according to the target flowability, workability, pot life, setting time, pore structure, mechanical strength, etc. Examples of BFS include blast furnace slag fine powders 3000, 4000, 6000, and 8000 as specified in JIS A6206:2024 "Blast furnace slag fine powder for concrete". Examples of fly ash (FA) include types I, II, III, and IV as defined in JIS A6201:2024 "Fly ash for concrete".

[0036] [Water and alkaline surfactant] Water is the site where components contained in the active filler and alkaline activators dissolve or ionize, and where the geopolymer structure is formed by condensation polymerization.

[0037] Alkaline activators are also called alkaline stimulants, alkalis, or bases in this field. Alkaline activators are generally at least one selected from the group consisting of alkali metal silicates, alkali metal hydroxides, and alkali metal carbonates. Examples of alkali metal silicates include sodium silicate and potassium silicate. Examples of alkali metal hydroxides include sodium hydroxide and potassium hydroxide. Examples of alkali metal carbonates include sodium carbonate and potassium carbonate.

[0038] The water and alkaline activator contained in the geopolymer composition generally originate from an aqueous solution of the alkaline activator (hereinafter referred to as "alkaline solution" in this disclosure). That is, the geopolymer composition contains water and an alkaline activator by mixing the active filler with the alkaline solution. In other words, a geopolymer composition containing an active filler, water, and an alkaline activator is a geopolymer composition obtained by mixing an active filler with an alkaline solution.

[0039] Examples of alkaline solutions used in forming the geopolymer composition include sodium water glass (i.e., sodium silicate solution), potassium water glass (i.e., potassium silicate solution), aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, aqueous sodium carbonate solution, aqueous potassium carbonate solution, and mixtures of at least two of these. Water may be added to ensure workability.

[0040] The type and concentration of the alkaline solution should be selected according to factors such as ensuring sufficient pot life based on the level of reactivity, and the mechanical strength after curing.

[0041] Examples of the alkaline solution include a mixture of sodium hydroxide glass, water, and sodium hydroxide; a mixture of sodium hydroxide glass and an aqueous sodium hydroxide solution; and a mixture of sodium hydroxide glass, water, and an aqueous sodium hydroxide solution.

[0042] Other examples of the alkaline solution include a mixture of sodium hydroxide glass, water, and sodium carbonate; a mixture of sodium hydroxide glass and an aqueous sodium carbonate solution; and a mixture of sodium hydroxide glass, water, and an aqueous sodium carbonate solution.

[0043] Generally, the stronger the alkalinity of an alkaline surfactant, the higher its reactivity with the active filler. Therefore, in geopolymer compositions, the stronger the alkalinity of the alkaline surfactant, the higher the mechanical strength of the cured product tends to be, and the stronger the alkalinity of the alkaline surfactant, the shorter the pot life tends to be. Based on the above common technical knowledge, when comparing sodium hydroxide and sodium carbonate as alkaline activators, sodium hydroxide is preferred from the viewpoint of high mechanical strength of the cured geopolymer, while sodium carbonate is preferred from the viewpoint of long pot life of the geopolymer composition.

[0044] The geopolymer composition of this disclosure preferably contains an alkali metal carbonate as the alkaline activator, and more preferably contains sodium carbonate. The form containing sodium carbonate as the alkaline activator, as demonstrated in the examples described below, when used in combination with a chemical admixture having a predetermined oxyalkylene group, can ensure compressive strength after curing while suppressing drying shrinkage during curing. When the geopolymer composition of this disclosure is used in combination with a chemical admixture having a predetermined oxyalkylene group, it is more preferable that the alkaline activator contains sodium silicate and sodium carbonate, from the viewpoint of suppressing drying shrinkage during curing while ensuring compressive strength after curing.

[0045] When using alkali metal carbonates as alkaline activators, the amount used should be selected according to the target fluidity, workability, pot life, setting time, pore structure, and mechanical strength. For example, the amount of alkali metal carbonate used is in the range of 3% to 9% by mass relative to the total amount of active filler. For example, the amount of sodium carbonate used is in the range of 3% to 9% by mass relative to the total amount of active filler.

[0046] [Chemical admixture containing an oxyalkylene group] In this disclosure, chemical admixtures having an oxyalkylene group are used with the expectation that they will exhibit a shrinkage-reducing effect in the geopolymer composition and the cured geopolymer.

[0047] In the geopolymer composition of the present disclosure, the content of the chemical admixture having an oxyalkylene group is preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 1.5% by mass or more, and still more preferably 2% by mass or more with respect to the total amount of the active filler from the viewpoint of suppressing the dry shrinkage of the cured geopolymer. In the geopolymer composition of the present disclosure, the content of the chemical admixture having an oxyalkylene group is preferably 5% by mass or less, more preferably 4% by mass or less, and still more preferably 3% by mass or less with respect to the total amount of the active filler from the viewpoint of ensuring the compressive strength of the cured geopolymer.

[0048] Specific examples of the chemical admixture having an oxyalkylene group are shown by structural formulas below. It is preferable to select a compound having the following chemical structure and satisfying a predetermined weight average molecular weight and HLB value, and use it as Chemical (1), Chemical (2) or Chemical (3).

[0049] Specific examples of the chemical admixture having an oxyalkylene group include the chemical compound represented by the following formula (1), the chemical compound represented by formula (2), the chemical compound represented by formula (3), the chemical compound represented by formula (4), and the chemical compound represented by formula (5).

[0050] Formula (1) R

[0051] -C(=O)-O-(A 1 O) n1 -R 2 <A

[0051] In formula (1), R 1 is an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms, A 1 O is a divalent alkylene oxide group having 2 to 4 carbon atoms, n1 is the average number of moles of alkylene oxide added and is a number from 1 to 200, and R 2 is 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, and R 3These are alkyl groups having 1 to 30 carbon atoms or alkenyl groups having 2 to 30 carbon atoms.

[0052] Equation (2) [HO-C(=O)-] k R 4 [-C(=O)-O-(A 2 O) n2 -R 5 ] m

[0053] In formula (2), R 4 A is a residue or single bond obtained by removing (k+m) carboxyl groups from a (k+m) valent polycarboxylic acid having 1 to 30 carbon atoms, where k and m are integers satisfying the relationships 0 ≤ k ≤ 5, 1 ≤ m ≤ 6, and 2 ≤ k+m ≤ 6. 2 O is a divalent alkylene oxide group with 2 to 4 carbon atoms, n2 is the average number of added moles of alkylene oxide, which is a number from 1 to 200, and R 5 These are a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or an alkenyl group having 2 to 30 carbon atoms. R 4 In this case, the carbon atoms of the carboxyl group (-COOH) are not included in the number of carbon atoms of the polycarboxylic acid.

[0054] Equation (3) [R 7 -(OA 3 ) n3 -O-] p R 6 [-OC(=O)-R 8 ] q

[0055] In formula (3), R 6 R is a residue obtained by removing (p+q) hydroxyl groups from a (p+q) valent polyhydric alcohol with 2 to 30 carbon atoms, 7 is a hydrogen atom or -OC(=O)-R 9 It is the basis, OA 3 R is a divalent oxyalkylene group with 2 to 4 carbon atoms, n3 is the average number of moles of oxyalkylene added, and is a number from 1 to 200. 8 R is an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms.9 is an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms, and p and q are integers satisfying the relationships 1 ≤ p ≤ 7, 1 ≤ q ≤ 7, and 2 ≤ p + q ≤ 8.

[0056] Equation (4) [H-(OA) 4 ) n4 -O-] r R 10 [-O-(A 5 O) n5 -C(=O)-R 11 ] s

[0057] In formula (4), R 10 OA is a residue obtained by removing (r+s) hydroxyl groups from a polyhydric alcohol with 2 to 30 carbon atoms and (r+s) valence. 4 n4 is a divalent oxyalkylene group with 2 to 4 carbon atoms, n4 is the average number of moles of oxyalkylene added, and is a number from 1 to 200. 11 A is an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms. 5 O is a divalent alkylene oxide group with 2 to 4 carbon atoms, n5 is the average number of added moles of alkylene oxide, ranging from 1 to 200, and r and s are integers satisfying the relationships 0 ≤ r ≤ 7, 1 ≤ s ≤ 8, and 2 ≤ r + s ≤ 8.

[0058] R in equations (1) to (4) 1 , R 2 , R 3 , R 5 , R 8 , R 9 , R 11When each of these is an alkyl group having 1 to 30 carbon atoms, for example, it may be a 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, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, heneicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, or triacontyl group, and alkyl groups having 3 or more carbon atoms may be linear, branched, cyclic, or any combination thereof.

[0059] R in equations (1) to (4) 1 , R 2 , R 3 , R 5 , R 8 , R 9 , R 11 When each of these is an alkenyl group having 2 to 30 carbon atoms, for example, it may be an ethenyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadecenyl group, eicocenyl group, heneicocenyl group, dococenyl group, tricocenyl group, tetracocenyl group, pentacocenyl group, hexacocenyl group, heptacocenyl group, octacocenyl group, nonacocenyl group, or triacontenyl group, and the alkenyl group having 3 or more carbon atoms may be linear, branched, cyclic, or any combination thereof.

[0060] A in equation (1), equation (2), or equation (4) 1 O, A 2 O, A 5 Each of the O groups is a divalent alkylene oxide group having 2 to 4 carbon atoms, specifically an ethylene oxide group, a propylene oxide group, and a butylene oxide group. When it is a propylene oxide group or a butylene oxide group, it may be linear, branched, or cyclic. If n1, n2, and n5 are each 2 or greater, (A 1 O) n1 , (A 2 O) n2 , (A 5 O) n5 Each of these may be a chain of one type of alkylene oxide group, or a chain of two or more types of alkylene oxide groups, and the chain of two or more types of alkylene oxide groups may have a block structure or a random structure.

[0061] OA in formula (3) or formula (4) 3 OA 4 Each of these is a divalent oxyalkylene group having 2 to 4 carbon atoms, specifically an oxyethylene group, an oxypropylene group, and an oxybutylene group, and when it is an oxypropylene group or an oxybutylene group, it may be linear, branched, or cyclic. If n3 and n4 are both 2 or greater, (OA 3 ) n3 (OA) 4 ) n4 Each of these may be a chain of one type of oxyalkylene group, or a chain of two or more types of oxyalkylene groups, and the chain of two or more types of oxyalkylene groups may have a block structure or a random structure.

[0062] R in equation (2) 4In this context, (k+m) valency polycarboxylic acids with 1 to 30 carbon atoms may be linear, branched, cyclic, or a combination thereof when they have 3 or more carbon atoms, and may contain unsaturated double bonds when they have 2 or more carbon atoms, and may have multiple carboxyl groups bonded to the same carbon atom. Since 2 ≤ k+m ≤ 6, (k+m) valency polycarboxylic acids with 1 to 30 carbon atoms are polycarboxylic acids having 2 to 6 carboxyl groups, and examples include aliphatic polycarboxylic acids (e.g., 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 (e.g., terephthalic acid, isophthalic acid, orthophthalic acid, trimellitic acid, pyromellitic acid); and alicyclic polycarboxylic acids (e.g., cyclohexane-1,4-dicarboxylic acid). Among these, aliphatic polycarboxylic acids having 2 to 12 carbon atoms are preferred, and succinic acid, adipic acid, sebacic acid, maleic acid, or fumaric acid are more preferred.

[0063] R 4 Preferably, it is a hydrocarbon group with 1 to 30 carbon atoms and a (k+m) valency.

[0064] R in equation (3) 6In this context, polyhydric alcohols with 2 to 30 carbon atoms and a (p+q) valency may be linear, branched, cyclic, or a combination thereof when they have 3 or more carbon atoms, and may contain unsaturated double bonds when they have 2 or more carbon atoms, and may have multiple hydroxyl groups bonded to the same carbon atom. Since 2 ≤ p+q ≤ 8, polyhydric alcohols with 2 to 30 carbon atoms and a (p+q) valency are polyhydric alcohols having 2 to 8 hydroxyl groups, and examples include dihydric alcohols (e.g., ethylene glycol, diethylene glycol, propylene glycol, butanediol, neopentyl glycol, hexanediol); trihydric to pentahydric alcohols (e.g., glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitan, diglycerin); and sugars and their derivatives (e.g., sucrose, glucose, fructose, methyl glycoside). Among these, polyhydric alcohols or sugars with a 3- to 5-valent pH are preferred, and sorbitol, sorbitan, polyglycerin, pentaerythritol, dipentaerythritol, or sucrose are more preferred.

[0065] R 6 Preferably, the hydrocarbon group has 2 to 30 carbon atoms and a (p+q) valency, and this hydrocarbon group may contain an ether bond.

[0066] R in equation (4) 10In this context, polyhydric alcohols with 2 to 30 carbon atoms and a (r+s) valency may be linear, branched, cyclic, or a combination thereof when they have 3 or more carbon atoms, and may contain unsaturated double bonds when they have 2 or more carbon atoms, and may have multiple hydroxyl groups bonded to the same carbon atom. Since 2 ≤ r+s ≤ 8, polyhydric alcohols with 2 to 30 carbon atoms and a (r+s) valency are polyhydric alcohols having 2 to 8 hydroxyl groups, and examples include dihydric alcohols (e.g., ethylene glycol, diethylene glycol, propylene glycol, butanediol, neopentyl glycol, hexanediol); trihydric to pentahydric alcohols (e.g., glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitan, diglycerin); and sugars and their derivatives (e.g., sucrose, glucose, fructose, methyl glycoside). Among these, polyhydric alcohols or sugars with a 3- to 5-valent pH are preferred, and sorbitol, sorbitan, polyglycerin, pentaerythritol, dipentaerythritol, or sucrose are more preferred.

[0067] R 10 Preferably, the hydrocarbon group has 2 to 30 carbon atoms and a (r+s) valency, and this hydrocarbon group may contain an ether bond.

[0068] Examples of hydrocarbon groups with 1 to 30 carbon atoms and a (k+m) valency, hydrocarbon groups with 2 to 30 carbon atoms and a (p+q) valency, and hydrocarbon groups with 2 to 30 carbon atoms and a (r+s) valency include groups obtained by removing (k+m), (p+q), and (r+s) hydrogen atoms, respectively, from alkanes or alkenes with 1 to 30 carbon atoms. Examples of alkanes 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, and triacontane. Their structures can be linear, branched, cyclic, or combinations thereof. Examples of alkenes with 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, tetracosene, pentacosene, hexacosene, heptacosene, octacosene, nonacosene, and triaconthene. Their structures can be linear, branched, cyclic, or combinations thereof.

[0069] A preferred example of the chemical represented by formula (1) is given. R 1 This is an alkyl group having 1 to 18 carbon atoms (linear, branched, cyclic, or a combination thereof) or an alkenyl group having 2 to 18 carbon atoms (linear, branched, cyclic, or a combination thereof), R 2 is a hydrogen atom, an alkyl group having 1 to 24 carbon atoms (linear, branched, cyclic, or a combination thereof), an alkenyl group having 2 to 18 carbon atoms (linear, branched, cyclic, or a combination thereof), or -C(=O)-R 3 It is a base, R 3 This is an alkyl group having 1 to 18 carbon atoms (linear, branched, cyclic, or a combination thereof), A 1 O is an ethylene oxide group or a propylene oxide group, n1 is between 1 and 100 or between 1 and 50.

[0070] A preferred example of the chemical represented by formula (2) is given. R 4 is a residue obtained by removing (k + m) carboxy groups from a polyvalent carboxylic acid having 2 to 10 carbon atoms and (k + m) valences, preferably a hydrocarbon group having 2 to 10 carbon atoms and (k + m) valences (linear, branched, cyclic, or a combination thereof), k is 0 or 1, and m is 1 or 2, R 5 is an alkyl group having 1 to 10 carbon atoms (linear, branched, cyclic, or a combination thereof), A 2 O is an ethylene oxide group or a propylene oxide group, n2 is 1 to 100 or 1 to 50.

[0071] Preferred examples of the chemical substance represented by formula (3) are given. R 6 is a residue obtained by removing (p + q) hydroxy groups from a polyhydric alcohol having 2 to 10 carbon atoms and (p + q) valences, preferably a hydrocarbon group having 2 to 10 carbon atoms and (p + q) valences (linear, branched, cyclic, or a combination thereof. The hydrocarbon group may contain an ether bond), p and q satisfy the relationship of 1 ≦ p ≦ 4, 1 ≦ q ≦ 4, and 2 ≦ p + q ≦ 6, R 7 is a hydrogen atom, R 8 is an alkyl group having 1 to 18 carbon atoms (linear, branched, cyclic, or a combination thereof) or an alkenyl group having 2 to 18 carbon atoms (linear, branched, cyclic, or a combination thereof), preferably an alkyl group having 10 to 18 carbon atoms or an alkenyl group having 10 to 18 carbon atoms, OA 3 is an oxyethylene group or an oxypropylene group, n3 is 1 to 100, 1 to 80, or 5 to 80.

[0072] Preferred examples of the chemical substance represented by formula (4) are given. <000044O>R 10is a residue obtained by removing (r + s) hydroxy groups from a polyhydric alcohol having (r + s) valences and 2 to 10 carbon atoms, preferably a hydrocarbon group having (r + s) valences and 2 to 10 carbon atoms (linear, branched, cyclic, or a combination thereof. The hydrocarbon group may contain an ether bond), r and s satisfy the relationship of 1 ≦ r ≦ 4, 1 ≦ s ≦ 4, and 2 ≦ r + s ≦ 6, R 11 is an alkyl group having 1 to 18 carbon atoms (linear, branched, cyclic, or a combination thereof) or an alkenyl group having 2 to 18 carbon atoms (linear, branched, cyclic, or a combination thereof), preferably an alkyl group having 10 to 18 carbon atoms or an alkenyl group having 10 to 18 carbon atoms, OA 4 is an oxyethylene group or an oxypropylene group, n4 is 1 to 100, 1 to 80, or 5 to 80, A 5 O is an ethylene oxide group or a propylene oxide group, n5 is 1 to 100, 1 to 80, or 5 to 80, n4 + n5 is 20 to 80.

[0073] Formula (5) R 12 O-(C2H4O)<000009​​​​​​​​​​​​​​​​​​​​​​​

[0076] R in equation (5) 13 When R is an alkyl group having 1 to 4 carbon atoms, it is a methyl group, an ethyl group, a propyl group, or a butyl group, and when it is a propyl group or a butyl group, it may be linear, branched, or cyclic. 13 It is preferable that this is a hydrogen atom or a methyl group.

[0077] In equation (5), n is preferably an integer between 1 and 15, and more preferably an integer between 1 and 10. 12 and R 13 When all of them are hydrogen atoms, n is preferably an integer between 2 and 15, and more preferably an integer between 2 and 10.

[0078] A preferred example of the chemical represented by formula (5) is given. R 12 is a hydrogen atom or a methyl group, R 13 is a hydrogen atom or a methyl group, n is an integer between 2 and 15 or an integer between 2 and 10.

[0079] [aggregate] The geopolymer compositions of this disclosure may contain aggregates. Examples of aggregates include various fine and coarse aggregates conventionally used in geopolymer mortar, geopolymer concrete, cement mortar, or cement concrete.

[0080] Examples of fine aggregates include crushed limestone sand, river sand, mountain sand, land sand, sea sand, silica sand, crushed sand, blast furnace slag fine aggregate, and recycled fine aggregate derived from concrete waste. Examples of coarse aggregates include crushed stone obtained by crushing andesite, rhyolite, hard sandstone, and limestone, as well as river gravel, mountain gravel, land gravel, blast furnace slag coarse aggregate, and recycled coarse aggregate derived from concrete waste. The type and content of these aggregates should be selected according to the target mechanical strength of the hardened geopolymer.

[0081] [Other materials] The geopolymer compositions of this disclosure may contain chemical admixtures other than chemical admixtures having oxyalkylene groups. Examples of other chemical admixtures include various chemical admixtures conventionally used in geopolymer mortar, geopolymer concrete, cement mortar, or cement concrete.

[0082] The geopolymer compositions of this disclosure may contain reinforcing materials. Examples of reinforcing materials include metal fibers, carbon fibers, glass fibers, basalt fibers, and organic fibers.

[0083] <Method for producing geopolymer compositions> The geopolymer composition of this disclosure is obtained by mixing the materials described above. The mixing of the materials is carried out, for example, by kneading using a mixer.

[0084] The order in which materials are mixed when preparing a geopolymer composition is not limited. For example, the active filler and aggregate are first mixed in a mixer, and then the alkaline solution and chemical admixture are added to the mixer and mixed. When mixing the active filler and aggregate in the mixer, reinforcing materials may be added and mixed as needed.

[0085] The mixing ratio of the active filler to the alkaline solution may be set appropriately depending on the type of active filler and the type and concentration of the alkaline solution. For example, the alkaline solution may be mixed in a mass ratio of 10 to 100 parts by mass of 100 parts by mass of active filler.

[0086] <Geopolymer hardened material> The geopolymer cured body of the present disclosure is obtained by curing the geopolymer composition of the present disclosure. The geopolymer composition is generally cured by a condensation polymerization reaction accompanied by dehydration to form a cured body.

[0087] One example of an embodiment of the method for producing a cured geopolymer according to this disclosure includes pouring a geopolymer composition into a mold to obtain a molded body, and curing the molded body. The geopolymer composition poured into the mold may be subjected to treatment such as degassing in accordance with conventional methods. The molded body may be demolded from the mold before or during the curing process.

[0088] In the method for producing a cured geopolymer according to this disclosure, the curing temperature and curing time for curing the geopolymer composition are not limited. Depending on the target mechanical strength of the cured geopolymer, curing may be performed at room temperature, by heating, by steam curing, by autoclave curing, by underwater curing, by air curing, by sealing, or by a combination thereof.

[0089] Since the compressive strength after curing can be ensured even when the geopolymer composition of this disclosure is cured without curing to prevent drying, the method for manufacturing the cured geopolymer of this disclosure offers a high degree of flexibility in curing. Furthermore, the geopolymer composition of this disclosure can reduce the materials and costs associated with curing. [Examples]

[0090] The geopolymer compositions and geopolymer cured products of this disclosure will be described in detail below with reference to examples. The geopolymer compositions and geopolymer cured products of this disclosure are not limited to the following examples.

[0091] <Material> The materials listed in Table 1 were prepared as components for the geopolymer composition. The weight-average molecular weight (Mw) and HLB values ​​of the chemical admixtures are shown in Table 2 and Figure 1.

[0092] [Table 1]

[0093] [Table 2]

[0094] <Preparation of geopolymer composition> Geopolymer mortar was prepared according to the formulations shown in Table 3. Chemical admixtures were added separately at a ratio of 3% by mass relative to the total amount of BFS and FA. The mixture was mixed in a mortar mixer for 3 minutes to produce the geopolymer mortar.

[0095] [Table 3]

[0096] <Evaluation of mortar> (1) Drying shrinkage The measurement was carried out in accordance with JIS A1129-3:2010 "Method for measuring length change of mortar and concrete - Part 3: Dial gauge method". Mortar was molded into a 40mm x 40mm x 160mm plate shape. It was sealed and cured at a temperature of 20±2℃ for one week, and after demolding, the length change was measured in an environment of 20±2℃ / relative humidity 60±5%.

[0097] (2) Compressive strength Mortar was molded into a cylindrical shape with a diameter of 50 mm and a height of 100 mm. For curing, sealed curing involved leaving the specimens undisturbed at a temperature of 20 ± 2 °C until the specified test age, while dry curing involved demolding after 2 days of sealed curing and leaving the specimens undisturbed at a temperature of 20 ± 2 °C and a relative humidity of 60 ± 5% until the specified test age. After reaching the specified age, the sealed cured specimens were also demolded, and both bottom surfaces (compression surfaces during the compression test) of the cylindrical specimens were polished to a finish, and the height was adjusted to within 95 mm to 100 mm. The compressive strength (N / mm²) was measured in accordance with JIS A1108:2018 "Test Method for Compressive Strength of Concrete". 2 The compressive strength was measured at 60 N / mm². 2 It is desirable to have more than the above.

[0098] (3) Cracks The cylindrical test specimens, after being dried and cured, were visually inspected to check for the presence or absence of cracks.

[0099] (4) Aesthetics The dried cylindrical test specimens were visually observed and classified as follows. G1: No aesthetic issues are observed. G2: Unburned carbon, likely of fly ash origin, is observed. G3: Efflorescence (white efflorescence) present.

[0100] Table 4 shows the measured values ​​of drying shrinkage and compressive strength, along with the results of visual observation. Table 5 shows the ratio values ​​of compressive strength.

[0101] [Table 4]

[0102] [Table 5]

[0103] Comparative Example 1 (No Chemical Admixture Used): Since no chemical admixture with shrinkage-reducing properties was used, drying shrinkage was significant. The compressive strength after 4 weeks of drying was approximately 60% of that after 4 weeks of sealed curing. Cracks were observed in the cylindrical specimen after drying.

[0104] Comparative Example 2 (Chemical Admixture C-01): Drying shrinkage was well suppressed. On the other hand, compressive strength was relatively low even with sealed curing. Compressive strength after 4 weeks of dry curing was even lower. Comparative Example 3 (Chemical Admixture C-02): Drying shrinkage was relatively large. Compressive strength was quite low even with sealed curing. Compressive strength after 4 weeks of drying curing was even lower.

[0105] Examples 1-8 (Chemical admixtures S-01-08): Drying shrinkage was suppressed. In all examples, the compressive strength after 4 weeks of sealing and curing was the same as that of Comparative Example 1 (96.4 N / mm²). 2 This represents over 80% of the original strength, and it was possible to ensure compressive strength after curing while suppressing drying shrinkage during curing.

[0106] Examples 1-5 (Chemical admixtures S-01-05): Compressive strength after 4 weeks of dry curing was 70 N / mm². 2 The above results were obtained in over 90% of cases with a 4-week curing period after sealing. Even when curing was performed without preventing drying, the compressive strength after curing was well maintained.

[0107] Examples 6-8 (Chemical admixtures S-06-08): Compressive strength of 60 N / mm² after 4 weeks of dry curing. 2 The above results were obtained in over 70% of cases with a 4-week curing period. Even when curing was performed without preventing drying, the compressive strength after curing was ensured.

[0108] Figure 1 shows the weight-average molecular weight (Mw) and HLB values ​​of the oxyalkylene group-containing chemical admixtures used in Examples 1-8 and Comparative Examples 2-3. The range labeled (1) in Figure 1 corresponds to chemical compound (1) with a weight-average molecular weight of 300 to 1000 and an HLB value of 15 to 20. The range labeled (2) in Figure 1 corresponds to chemical compounds (2) with a weight-average molecular weight of 150 to 300 and an HLB value of 15 to less than 20. The range labeled (3) in Figure 1 corresponds to chemical compound (3) with a weight-average molecular weight of 150-300 and an HLB value of 10-15.

Claims

1. Activated filler, Water and, Alkaline activators and, It contains at least one chemical admixture selected from the group consisting of ester compounds having an oxyalkylene group, ether compounds having an oxyalkylene group, and glycol compounds having an oxyalkylene group, The aforementioned chemical admixture A chemical substance having a weight-average molecular weight of 300 to 1000 and an HLB value of 15 to 20 (1), Chemicals (2) with a weight-average molecular weight of 150 to 300 and an HLB value of 15 to less than 20, and It is at least one selected from the group consisting of chemicals (3) having a weight-average molecular weight of 150 to 300 and an HLB value of 10 to 15. Geopolymer composition.

2. The aforementioned chemical admixture Compounds (1a) having a weight-average molecular weight of 380 to 1000 and an HLB value of 18 to 20, and At least one compound selected from the group consisting of compounds (2a) having a weight-average molecular weight of 165 to 250 and an HLB value of 16 to 19. The geopolymer composition according to claim 1.

3. The geopolymer composition according to claim 1, wherein the alkaline activator comprises an alkali metal carbonate.

4. The geopolymer composition according to claim 1, wherein the total amount of the chemical admixture is 0.5% to 3% by mass relative to the total amount of the active filler.

5. A geopolymer cured body, which is a cured product of the geopolymer composition according to any one of claims 1 to 4.

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