Geopolymer composition and hardened geopolymer

Abstract

To provide a geopolymer composition that gives a cured product having small drying shrinkage strain, and a cured geopolymer having small drying shrinkage strain.SOLUTION: A geopolymer composition contains an active filler, an aqueous alkali solution containing silicate, and a shrinkage reducer. The aqueous alkali solution containing silicate satisfies a requirement (1): 1.2≤A1 / A2≤2.0, where A1 is the amount of substance of SiO2 (mol) when silicon contained in silicate is expressed by the formula SiO2, and A2 is the amount of substance of M2O (mol) when all the alkali metals M contained in the aqueous alkali solution containing silicate form M2O.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to geopolymer compositions and hardened geopolymers. [Background technology]

[0002] Patent Document 1 discloses a shrinkage-reducing agent for geopolymers, which is an ester-based compound having an oxyalkylene group, and a geopolymer-forming composition and a geopolymer hardened body containing the shrinkage-reducing agent.

[0003] Patent Document 2 discloses a shrinkage-reducing agent for geopolymers that is a glycol ether-based compound, and a geopolymer-forming composition and a geopolymer hardened body that contain the shrinkage-reducing agent.

[0004] Patent Document 3 discloses an admixture for geopolymers containing a shrinkage-reducing agent that is an oxyalkylene alkyl ether compound and a shrinkage-reducing aid that is an aliphatic oxycarboxylic acid compound, as well as a geopolymer-forming composition and a geopolymer hardened body that contain the admixture.

[0005] Patent Document 4 discloses a geopolymer composition containing an active filler including fly ash and blast furnace slag, an alkaline solution including sodium silicate and / or sodium hydroxide, and a cement mineral-based expanding material. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2017-202963 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-150195 [Patent Document 3] Japanese Patent Application Publication No. 2017-202964 [Patent Document 4] Japanese Patent Application Publication No. 2020-055696 Summary of the Invention [Problem to be solved by the invention]

[0007] Geopolymer compositions harden through a condensation polymerization reaction accompanied by dehydration, and the dehydrated water remains as pore water in the hardened geopolymer. When the hardened geopolymer is placed in a relatively low humidity environment, the pore water dissipates, causing the hardened geopolymer to shrink upon drying.

[0008] The present disclosure aims to provide a geopolymer composition having a low drying shrinkage strain of the resulting hardened body, and a geopolymer hardened body having a low drying shrinkage strain. [Means for solving the problem]

[0009] Specific means for solving the above problems include the following aspects. <1> an active filler, an alkaline solution containing a silicate, and a shrinkage reducing agent; A geopolymer composition, wherein the alkaline solution containing the silicate satisfies the following requirement (1): Requirement (1): 1.2≦A1 / A2≦2.0 A1 is the amount of substance (mol) of SiO2 when the silicon contained in the silicate is expressed by the composition formula SiO2. A2 is the amount of substance (mol) of M2O when all the alkali metals M contained in the alkali solution containing the silicate form M2O. <2> The content of the shrinkage reducing agent is 0.5% by mass to 5% by mass based on the total amount of the active filler. <1> The geopolymer composition according to claim 1. <3> The active filler contains at least one of fly ash and ground granulated blast furnace slag. <1> or <2> The geopolymer composition according to claim 1. <4> <1> ~ <3> A hardened geopolymer body which is a hardened product of the geopolymer composition described in any one of the above. [Effects of the Invention]

[0010] According to the present disclosure, a geopolymer composition having a low drying shrinkage strain of the resulting hardened body and a geopolymer hardened body having a low drying shrinkage strain are provided. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes embodiments of the present invention. These descriptions and examples are intended to illustrate the embodiments and are not intended to limit the scope of the present invention.

[0012] In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples.

[0013] <Geopolymer composition> The geopolymer composition of the present disclosure is a composition in a state called a slurry, fresh, etc., and the geopolymer composition of the present disclosure hardens to obtain the hardened geopolymer of the present disclosure.

[0014] The geopolymer composition of the present disclosure comprises an active filler, an alkaline solution containing silicate, and a shrinkage reducing agent, wherein the alkaline solution containing silicate satisfies the following requirement (1).

[0015] Requirement (1): 1.2≦A1 / A2≦2.0

[0016] A1 is the amount of SiO2 (mol) when the silicon contained in silicate is expressed by the composition formula SiO2. A1 is generally equal to the amount (mol) of silicic acid oxide contained in the silicate.

[0017] A2 is the amount of substance (mol) of M2O when all alkali metals M contained in the alkali solution containing silicate form M2O. The alkali metal is, for example, sodium or potassium. The alkali metal includes both the alkali metal contained in the silicate and the alkali metal contained in the component other than the silicate. For example, when sodium and potassium are contained as alkali metals, A2 = (amount of substance of Na2O + amount of substance of K2O).

[0018] Conventionally, in the technical field of concrete, the amount of sodium hydroxide solution is converted into the amount of Na2O to set the mortar mix (for example, JIS A1146:2017 "Test method for alkali-silica reactivity of aggregates"), or the sum of the contents of Na2O and K2O is converted into the amount of Na2O to set the concrete mix (for example, JIS A5308:2019 "Ready-mixed concrete" and "Annex B Methods for suppressing alkali-silica reaction"). This technical concept is applied to the amount of substance A2 in this disclosure.

[0019] In this disclosure, "drying shrinkage strain" refers to the rate of change in length due to drying, and is a physical quantity measured according to JIS A1129-3:2010 "Method for measuring change in length of mortar and concrete - Part 3: Dial gauge method."

[0020] The drying shrinkage of a hardened geopolymer body can be suppressed by adding a shrinkage-reducing agent. The inventors of the present disclosure have discovered that the drying shrinkage of a hardened geopolymer body varies depending on the A1 / A2 value of the alkaline solution in the geopolymer composition. In a geopolymer composition containing a shrinkage-reducing agent, the lower the A1 / A2 value of the alkaline solution, the smaller the drying shrinkage strain of the hardened geopolymer tends to be. From this perspective, the geopolymer composition of the present disclosure has A1 / A2≦2.0, preferably A1 / A2≦1.8, and more preferably A1 / A2≦1.5. However, if the A1 / A2 value of the alkaline solution in a geopolymer composition containing a shrinkage-reducing agent falls below 1.2, the drying shrinkage strain of the hardened geopolymer will increase. From this perspective, the geopolymer composition of the present disclosure has a ratio of 1.2 ≦ A1 / A2, preferably 1.3 ≦ A1 / A2, and more preferably 1.4 ≦ A1 / A2. The drying shrinkage strain of the hardened geopolymer body varies depending on the A1 / A2 value of the alkaline solution in the geopolymer composition, even when no shrinkage-reducing agent is included, but this is more pronounced when a shrinkage-reducing agent is included.

[0021] Furthermore, the inventors of the present disclosure have discovered that the compressive strength of a hardened geopolymer varies depending on the A1 / A2 value of the alkaline solution in a geopolymer composition containing a shrinkage-reducing agent. If the A1 / A2 value of the alkaline solution in the geopolymer composition is too large or too small, the compressive strength of the hardened geopolymer tends to decrease. It is preferable that the A1 / A2 value of the geopolymer composition of the present disclosure be within the above range, in order to ensure the compressive strength of the hardened geopolymer.

[0022] In addition, it is preferable that the A1 / A2 value of the alkali solution in the geopolymer composition is not too small in order to prevent excess alkali from remaining unreacted in the hardened geopolymer. Unreacted alkali remaining in the hardened geopolymer may react with carbon dioxide in the air and cause efflorescence.

[0023] The materials that make up the geopolymer composition of the present disclosure are described in detail below.

[0024] [Active filler] The active filler is generally a powder based on aluminum silicate. Examples of active fillers include fly ash, ground granulated blast furnace slag, metakaolin, silica fume, ground zeolite, ground granulated refuse incineration ash molten slag, ground granulated sewage sludge molten slag, volcanic ash, rice husk ash, fluidized bed coal ash, paper sludge incineration ash, and mixtures of at least two of these.

[0025] An example of an embodiment of an active filler is a mixture of fly ash (FA) and ground granulated blast furnace slag (BFS). Geopolymer compositions containing FA tend to have excellent fluidity and workability. Geopolymer compositions containing BFS tend to have high compressive strength in their hardened form. By mixing FA and BFS, a hardened geopolymer with a good balance of fluidity, workability, and mechanical strength can be obtained.

[0026] The quality of the FA (e.g., density, fineness), the quality of the BFS (e.g., density, fineness), and the mixing ratio of the FA and BFS are not limited, and may be selected depending on the target fluidity, workability, pot life, setting time, pore structure, mechanical strength, etc. Examples of FA include types I, II, III, and IV as defined in JIS A6201:2015. Examples of BFS include ground granulated blast furnace slag 3000, 4000, 6000, and 8000 as specified in JIS A6206:2013.

[0027] [Alkaline solution containing silicate] The alkaline solution contains at least a silicate as a base, which is also referred to in the art as an alkaline activator, alkaline stimulator, etc.

[0028] Examples of silicates include alkali metal silicates, specifically sodium silicate, potassium silicate, and mixtures thereof.

[0029] The alkaline solution containing silicate may contain a base other than silicate. Other bases include alkali metal hydroxides (eg, sodium hydroxide, potassium hydroxide) and alkali metal carbonates (eg, sodium carbonate, potassium carbonate).

[0030] It is believed that at least some of the silicon atoms contained in the silicate are incorporated into the geopolymer structure. Metal ions derived from silicates and other bases (e.g., Na + , K. + ) is believed to be retained within the geopolymer structure.

[0031] The alkaline solution containing silicate contains water. Therefore, the geopolymer composition of the present disclosure contains water. Water is the site where the components contained in the active filler and the base are dissolved or ionized, and where the geopolymer structure is formed by a condensation polymerization reaction.

[0032] Specific examples of the alkaline solution containing silicate include: at least one selected from the group consisting of sodium silicate solution (sodium silicate water glass) and potassium silicate solution (potassium silicate water glass); and a mixed solution of at least one selected from the group consisting of a sodium silicate solution (water glass of sodium silicate) and a potassium silicate solution (water glass of potassium silicate) with at least one selected from the group consisting of an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, an aqueous sodium carbonate solution, and an aqueous potassium carbonate solution. From the viewpoint of ensuring workability, water may be further mixed.

[0033] The type and concentration of the alkaline solution containing silicate may be selected depending on the level of reactivity of the base, ensuring a usable time, mechanical strength after hardening, and the like.

[0034] An example of an embodiment of the alkaline solution containing silicate is a mixture of a sodium silicate solution (sodium silicate water glass) and an aqueous sodium hydroxide solution.

[0035] [Shrinkage reducing agent] The shrinkage reducing agent includes known chemicals known to have a shrinkage reducing effect in geopolymer mortar or geopolymer concrete, and known chemicals known to have a shrinkage reducing effect in cement mortar or cement concrete.

[0036] In the geopolymer composition of the present disclosure, the content of the shrinkage reducing agent is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 1.5% by mass or more, and even more preferably 2% by mass or more, based on the total amount of active filler, from the viewpoint of reducing the drying shrinkage strain of the hardened geopolymer body. In the geopolymer composition of the present disclosure, the content of the shrinkage reducing agent is preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less, based on the total amount of active filler, in order to ensure the compressive strength of the hardened geopolymer body.

[0037] Specific examples of shrinkage reducing agents include ester compounds having an oxyalkylene group, ether compounds having an oxyalkylene group, and glycol compounds having an oxyalkylene group. More specifically, examples include chemical substances represented by the following formula (1), (2), (3), (4), and (5).

[0038] Formula (1) R 1 -C(=O)-O-(A 1 O) n1 -R 2

[0039] 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, and 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 -C(=O)-R3 is a group, and R 3 is an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms.

[0040] Formula (2) [HO-C(=O)-] k R 4 [-C(=O)-O-(A 2 O) n2 -R 5 ] m

[0041] In formula (2), R 4 is a residue obtained by removing (k+m) carboxy groups from a (k+m)-valent polycarboxylic acid having 1 to 30 carbon atoms, or a single bond, and k and m are integers satisfying the relationships 0≦k≦5, 1≦m≦6, and 2≦k+m≦6; A 2 O is a divalent alkylene oxide group having 2 to 4 carbon atoms, n2 is the average number of moles of alkylene oxide added and is a number from 1 to 200, and R 5 is 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 atom of the carboxy group (-COOH) is not included in the number of carbon atoms of the polycarboxylic acid.

[0042] Equation (3) [R 7 -(OA 3 ) n3 -O-] p R 6 [-OC(=O)-R 8 ] q

[0043] In formula (3), R 6 is a residue obtained by removing (p+q) hydroxy groups from a (p+q)-valent polyhydric alcohol having 2 to 30 carbon atoms, and R 7 is a hydrogen atom or -OC(=O)-R 9 Based on OA 3 is a divalent oxyalkylene group having 2 to 4 carbon atoms, n3 is the average number of moles of oxyalkylene added and is a number of 1 to 200, and R 8is an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms, and R 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 that satisfy the relationships 1≦p≦7, 1≦q≦7, and 2≦p+q≦8.

[0044] Formula (4) [H-(OA 4 ) n4 -O-] r R 10 [-O-(A 5 O) n5 -C(=O)-R 11 ] s

[0045] In formula (4), R 10 is a residue obtained by removing (r+s) hydroxy groups from a (r+s)-valent polyhydric alcohol having 2 to 30 carbon atoms, and OA 4 is a divalent oxyalkylene group having 2 to 4 carbon atoms, n4 is the average number of moles of oxyalkylene added and is a number of 1 to 200, and R 11 is an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms, and A 5 O is a divalent alkylene oxide group having 2 to 4 carbon atoms, n5 is the average number of moles of alkylene oxide added and is a number of 1 to 200, and r and s are integers that satisfy the relationships 0≦r≦7, 1≦s≦8, and 2≦r+s≦8.

[0046] R in formulas (1) to (4) 1 , R 2 , R 3 , R 5 , R 8 , R 9 , R 11are each an alkyl group having 1 to 30 carbon atoms, it is, for example, 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 the alkyl group having 3 or more carbon atoms may be linear, branched, cyclic, or a combination thereof.

[0047] R in formulas (1) to (4) 1 , R 2 , R 3 , R 5 , R 8 , R 9 , R 11 are each an alkenyl group having 2 to 30 carbon atoms, for example, an ethenyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, a nonadecenyl group, an eicosenyl group, a heneicosenyl group, a docosenyl group, a tricosenyl group, a tetracosenyl group, a pentacosenyl group, a hexacosenyl group, a heptacosenyl group, an octacosenyl group, a nonacosenyl group, or a triacontenyl group, and an alkenyl group having 3 or more carbon atoms may be linear, branched, cyclic, or a combination thereof.

[0048] A in formula (1), formula (2) or formula (4) 1 O, A 2 O, A 5 Each O is a divalent alkylene oxide group having 2 to 4 carbon atoms, specifically an ethylene oxide group, a propylene oxide group, or a butylene oxide group, and 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 more, (A 1 O) n1 , (A 2 O) n2 , (A 5 O) n5 may each be a chain of one type of alkylene oxide group, or may be a chain of two or more types of alkylene oxide groups, and the chains of two or more types of alkylene oxide groups may have a block structure or a random structure.

[0049] OA in formula (3) or formula (4) 3 ,OA 4 are each a divalent oxyalkylene group having 2 to 4 carbon atoms, specifically an oxyethylene group, an oxypropylene group, or an oxybutylene group, and when they are an oxypropylene group or an oxybutylene group, they may be linear, branched, or cyclic. If n3 and n4 are 2 or more, (OA 3 ) n3 , (OA 4 ) n4 may each 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.

[0050] R in equation (2) 4The (k+m)-valent polycarboxylic acid having 1 to 30 carbon atoms may be linear, branched, cyclic, or a combination thereof when it has three or more carbon atoms, and may contain an unsaturated double bond when it has two or more carbon atoms, and may have multiple carboxy groups bonded to the same carbon atom. The (k+m)-valent polycarboxylic acid having 1 to 30 carbon atoms satisfies 2≦k+m≦6, and is therefore a polycarboxylic acid having 2 to 6 carboxy groups, and examples thereof 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.

[0051] R 4 is preferably a (k+m) valent hydrocarbon group having 1 to 30 carbon atoms.

[0052] R in equation (3) 6The (p+q)-valent polyhydric alcohol having 2 to 30 carbon atoms in the formula (1) may be linear, branched, cyclic, or a combination thereof when it has three or more carbon atoms, and may contain an unsaturated double bond when it has two or more carbon atoms, and may have multiple hydroxy groups bonded to the same carbon atom. The (p+q)-valent polyhydric alcohol having 2 to 30 carbon atoms satisfies 2≦p+q≦8, and therefore is a polyhydric alcohol having 2 to 8 hydroxy groups, and examples thereof include dihydric alcohols (e.g., ethylene glycol, diethylene glycol, propylene glycol, butanediol, neopentyl glycol, hexanediol); trihydric to pentahydric polyhydric alcohols (e.g., glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitan, diglycerin); and sugars and derivatives thereof (e.g., sucrose, glucose, fructose, methyl glycoside). Among these, trihydric to pentahydric polyalcohols or sugars are preferred, and sorbitol, sorbitan, polyglycerin, pentaerythritol, dipentaerythritol or sucrose are more preferred.

[0053] R 6 As the alkyl group, a (p+q)-valent hydrocarbon group having 2 to 30 carbon atoms is preferred, and the hydrocarbon group may contain an ether bond.

[0054] R in equation (4) 10The (r+s)-valent polyhydric alcohol having 2 to 30 carbon atoms in the formula (1) may be linear, branched, cyclic, or a combination thereof when it has three or more carbon atoms, and may contain an unsaturated double bond when it has two or more carbon atoms, and may have multiple hydroxy groups bonded to the same carbon atom. The (r+s)-valent polyhydric alcohol having 2 to 30 carbon atoms satisfies 2≦r+s≦8, and is therefore a polyhydric alcohol having 2 to 8 hydroxy groups, and examples thereof include dihydric alcohols (e.g., ethylene glycol, diethylene glycol, propylene glycol, butanediol, neopentyl glycol, hexanediol); trihydric to pentahydric polyhydric alcohols (e.g., glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitan, diglycerin); and sugars and derivatives thereof (e.g., sucrose, glucose, fructose, methyl glycoside). Among these, trihydric to pentahydric polyalcohols or sugars are preferred, and sorbitol, sorbitan, polyglycerin, pentaerythritol, dipentaerythritol or sucrose are more preferred.

[0055] R 10 As the alkyl group, a hydrocarbon group having 2 to 30 carbon atoms and a valence of (r+s) is preferred, and the hydrocarbon group may contain an ether bond.

[0056] Examples of 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 include groups obtained by removing (k+m), (p+q), and (r+s) hydrogen atoms from an alkane having 1 to 30 carbon atoms or an alkene having 2 to 30 carbon atoms, respectively. 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, and the structure thereof may be linear, branched, or cyclic, or a combination thereof. Examples of alkenes 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, tetracosene, pentacosene, hexacosene, heptacosene, octacosene, nonacosene, and triacontene, and the structure thereof may be linear, branched, or cyclic, or a combination thereof.

[0057] Preferred examples of the chemical substance represented by formula (1) are as follows. R 1 is an alkyl group (linear, branched, cyclic, or a combination thereof) having 1 to 18 carbon atoms or an alkenyl group (linear, branched, cyclic, or a combination thereof) having 2 to 18 carbon atoms, 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 is a group, and R 3 is an alkyl group (linear, branched, cyclic, or a combination thereof) having 1 to 18 carbon atoms, A 1 O is an ethylene oxide group or a propylene oxide group, n1 is 1 to 100 or 1 to 50.

[0058] Preferred examples of the chemical substance represented by formula (2) are as follows. R 4 is a residue obtained by removing (k+m) carboxy groups from a (k+m)-valent polycarboxylic acid having 2 to 10 carbon atoms, and is preferably a (k+m)-valent hydrocarbon group (linear, branched, cyclic, or a combination thereof) having 2 to 10 carbon atoms; k is 0 or 1, 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.

[0059] Preferred examples of the chemical substance represented by formula (3) are as follows: R 6 is a residue obtained by removing (p+q) hydroxy groups from a (p+q)-valent polyhydric alcohol having 2 to 10 carbon atoms, and is preferably a (p+q)-valent hydrocarbon group having 2 to 10 carbon atoms (linear, branched, cyclic, or a combination thereof; the hydrocarbon group may contain an ether bond), p and q satisfy the relationships 1≦p≦4, 1≦q≦4, and 2≦p+q≦6, R 7 is a hydrogen atom, R 8 is an alkyl group (linear, branched, cyclic, or a combination thereof) having 1 to 18 carbon atoms or an alkenyl group (linear, branched, cyclic, or a combination thereof) having 2 to 18 carbon atoms, preferably an alkyl group having 10 to 18 carbon atoms or an alkenyl group having 10 to 18 carbon atoms, Office Automation 3 is an oxyethylene group or an oxypropylene group, n3 is 1 to 100, 1 to 80, or 5 to 80.

[0060] Preferred examples of the chemical substance represented by formula (4) are as follows: R 10is a residue obtained by removing (r+s) hydroxy groups from an (r+s)-valent polyhydric alcohol having 2 to 10 carbon atoms, and is preferably an (r+s)-valent hydrocarbon group having 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 relationships 1≦r≦4, 1≦s≦4, and 2≦r+s≦6, R 11 is an alkyl group (linear, branched, cyclic, or a combination thereof) having 1 to 18 carbon atoms or an alkenyl group (linear, branched, cyclic, or a combination thereof) having 2 to 18 carbon atoms, preferably an alkyl group having 10 to 18 carbon atoms or an alkenyl group having 10 to 18 carbon atoms, Office Automation 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.

[0061] Equation (5) R 12 O-(C2H4O) n -R 13

[0062] In formula (5), R 12 and R 13 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 20, provided that R 12 and R 13 are all hydrogen atoms, n is an integer of 2 to 20.

[0063] R in equation (5) 12 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 R is a propyl group or a butyl group, it may be linear, branched, or cyclic. 12 is preferably a hydrogen atom or a methyl group.

[0064] 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 R is a propyl group or a butyl group, it may be linear, branched, or cyclic. 13 is preferably a hydrogen atom or a methyl group.

[0065] In formula (5), n is preferably an integer of 1 to 15, and more preferably an integer of 1 to 10. 12 and R 13 When all of are hydrogen atoms, n is preferably an integer of 2 to 15, and more preferably an integer of 2 to 10.

[0066] Preferred examples of the chemical substance represented by formula (5) are as follows: R 12 is a hydrogen atom or a methyl group, R 13 is a hydrogen atom or a methyl group, n is an integer of 2 to 15 or an integer of 2 to 10.

[0067] [aggregate] The geopolymer compositions of the present disclosure may also include aggregates, including various fine and coarse aggregates conventionally used in geopolymer mortars or concretes or cement mortars or concretes.

[0068] Examples of fine aggregate include river sand, mountain sand, land sand, sea sand, silica sand, crushed sand, crushed lime sand, blast furnace slag fine aggregate, and recycled fine aggregate derived from concrete waste. Examples of coarse aggregate include crushed stone such as andesite, rhyolite, hard sandstone, and limestone, 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 may be selected depending on the desired mechanical strength of the hardened geopolymer body.

[0069] [Other ingredients] The geopolymer composition of the present disclosure may contain other chemical admixtures other than the shrinkage reducing agent, including various chemical admixtures conventionally used in geopolymer mortar or concrete or cement mortar or concrete.

[0070] The geopolymer compositions of the present disclosure may contain reinforcing materials, such as metal fibers, carbon fibers, glass fibers, and basalt fibers.

[0071] <Method of manufacturing geopolymer composition> The geopolymer composition of the present disclosure can be obtained by mixing the above-described materials. The mixing of the materials can be carried out, for example, by kneading using a mixer.

[0072] The order of mixing the materials when preparing the geopolymer composition is not limited. For example, first mix the active filler and aggregate, then add the alkaline solution and knead, and then add the shrinkage reducing agent and knead to obtain the geopolymer composition.

[0073] The mixing ratio of the active filler to the alkaline solution may be appropriately set depending on the type of active filler and the type and concentration of the alkaline solution. For example, 100 parts by mass of the active filler is mixed with 10 to 100 parts by mass of the alkaline solution.

[0074] <Hardened geopolymer> The hardened geopolymer of the present disclosure can be obtained by hardening the geopolymer composition of the present disclosure. Specifically, the geopolymer composition is poured into a mold and hardened to obtain a hardened geopolymer. The geopolymer composition poured into the mold may be subjected to treatment such as degassing according to a conventional method. The geopolymer composition poured into the mold generally hardens through a condensation polymerization reaction accompanied by dehydration to form a hardened geopolymer.

[0075] The curing temperature and curing time of the hardened geopolymer of the present disclosure are not limited. Depending on the target mechanical strength of the hardened geopolymer, for example, heat curing, steam curing, autoclave curing, water curing, air curing, room temperature curing, sealed curing, or a combination thereof may be used. [Example]

[0076] The geopolymer composition and hardened geopolymer of the present disclosure will be specifically described below using examples. The geopolymer composition and hardened geopolymer of the present disclosure are not limited to the following examples.

[0077] [material] The following materials were prepared for the geopolymer composition: (1) Active filler Ground granulated blast furnace slag (BFS): density 2.91 g / cm 3 , powder degree 4220cm 2 / g Fly ash (FA): density 2.28g / cm 3 , powder degree 3670cm 2 / g (2) Alkaline solution Sodium silicate solution (WG): Sodium silicate No. 2, density 1.50 g / cm 3 , SiO2: 31.41 mass%, Na2O: 12.29 mass%, SiO2 / Na2O molar ratio 2.64 Sodium hydroxide solution (NH): concentration 30.5% by mass, molar concentration 10 mol / l, density 1.33 g / cm 3 Water (W): Tap water (3) Fine aggregate ·Standard sand (SS): Absolute dry density 2.64g / cm 3 , water absorption rate 0.42% (4) Shrinkage reducing agent Polyether shrinkage reducer: The main compound is HO-(CH2CH2O)9-H, weight average molecular weight 400, density 0.93g / cm 3 , Toho Chemical Industry Co., Ltd.

[0078] [Preparation of geopolymer composition] Geopolymer mortar was prepared as the geopolymer composition. The materials were mixed as shown in Table 1, and the shrinkage reducing agent was added at the rate (mass%) shown in Table 2. The mixture was then mixed for 3 minutes in a mortar mixer to prepare a geopolymer composition. The shrinkage reducing agent was added in an externally calculated mass % relative to the amount of active filler (the total amount of BFS and FA).

[0079] The abbreviations in Tables 1 and 2 have the following meanings. AS / P: Mass ratio of alkaline solution (AS = WG + NH + W) to active filler (P = BFS + FA) ·NH / AS··· Mass ratio of sodium hydroxide solution (NH) to alkaline solution (AS = WG + NH + W)

[0080] [Table 1]

[0081] An example of the procedure for calculating the A1 / A2 value will be described using Mortar 1 as an example. Amount of SiO2 / Amount of Na2O = (mass of SiO2 / formula weight of SiO2) / (mass of Na2O / formula weight of Na2O) = (mass of SiO2 / mass of Na2O) x 1.032 When the silicon contained in 357 units of sodium silicate No. 2 is expressed by the formula SiO2, the mass of SiO2 is calculated. In other words, the mass of SiO2 contained in 357 units of sodium silicate No. 2 = 357 x 31.41% = 112.13 When alkali metal M contained in 357 units of sodium silicate No. 2 forms M2O, the mass of M2O, i.e., the mass of Na2O contained in 357 units of sodium silicate No. 2 = 357 × 12.29% = 43.88 When the alkali metal M contained in 23 unit amounts of aqueous sodium hydroxide (containing 30.5 mass% NaOH) forms MO, the mass of MO, in other words, the mass of NaO when the Na contained in 23 unit amounts of aqueous sodium hydroxide forms NaO = 23 × 30.5% / (formula weight of NaOH × 2 / formula weight of NaO) = 5.44 A1 / A2 =112.13 / (43.88+5.44)×1.032 =2.35

[0082] [Evaluation of hardened geopolymers] (1) Drying shrinkage The test was conducted in accordance with JIS A1129-3:2010. 40mm x 40mm x 160mm specimens were sealed and cured at a temperature of 20±2°C until they were one week old, then demolded and stored in an environment of 20±2°C and 60±5% humidity for 26 weeks, after which the change in length was measured. Table 2 shows the measurement results.

[0083] (2) Compressive strength Test specimens were prepared using a formwork measuring 50 mm in diameter and 100 mm in length, and then sealed and cured at a temperature of 20±2°C until the specified age was reached. Compression tests were conducted in accordance with JIS A1108:2018 at ages of 1 week, 4 weeks, and 13 weeks. Table 2 shows the test results.

[0084] [Table 2]

[0085] -Drying shrinkage strain- In the group containing a shrinkage-reducing agent (Comparative Example 1, Examples 1 to 3, and Comparative Example 2), the lower the A1 / A2 value, the smaller the drying shrinkage. However, when the A1 / A2 value falls below 1.2, the drying shrinkage begins to increase. The above phenomenon is also observed in the groups that do not contain a shrinkage-reducing agent (Comparative Examples 3 to 7), but is more pronounced in the groups that contain a shrinkage-reducing agent.

[0086] Comparing Examples 1 to 3 and Comparative Examples 4 to 6, in which the A1 / A2 value is in the range of 1.2 to 2.0, Examples 1 to 3, which contain a shrinkage-reducing agent, have smaller drying shrinkage strains than Comparative Examples 4 to 6, which do not contain a shrinkage-reducing agent, and the drying shrinkage reduction effect of adding a shrinkage-reducing agent is (Comparative Example - Example) / Comparative Example = about 45%. In a comparison between Comparative Example 1 and Comparative Example 3, both of which have an A1 / A2 value of 2.35, Comparative Example 1, which contains a shrinkage-reducing agent, has a smaller drying shrinkage strain than Comparative Example 3, which does not contain a shrinkage-reducing agent. The drying shrinkage reduction effect of adding a shrinkage-reducing agent is (Comparative Example 3 - Comparative Example 1) / Comparative Example 3 = approximately 20%. Comparing Comparative Example 2 and Comparative Example 7, both of which have an A1 / A2 value of 1.00, Comparative Example 2, which contains a shrinkage-reducing agent, has a smaller drying shrinkage strain than Comparative Example 7, which does not contain a shrinkage-reducing agent, and the drying shrinkage reduction effect of adding a shrinkage-reducing agent is (Comparative Example 7 - Comparative Example 2) / Comparative Example 7 = approximately 35%. Therefore, the drying shrinkage strain reducing effect of adding a shrinkage reducing agent is greater in examples where the A1 / A2 value is in the range of 1.2 to 2.0 than in examples where the A1 / A2 value is 2.35 and examples where the A1 / A2 value is 1.00.

[0087] -Compression strength- In the group containing a shrinkage-reducing agent (Comparative Example 1, Examples 1 to 3, and Comparative Example 2), Examples 1 to 3, in which the A1 / A2 value is in the range of 1.2 to 2.0, have higher compressive strength than Comparative Example 1, in which the A1 / A2 value is 2.35, and Comparative Example 2, in which the A1 / A2 value is 1.00.

Claims

1. The composition includes an active filler, an alkaline solution containing a silicate, and a shrinkage reducing agent which is an ether-based compound having an oxyalkylene group, the content of the shrinkage reducing agent is 0.5% by weight to 5% by weight based on the total amount of the active filler; The alkaline solution containing silicate satisfies the following requirement (1): Geopolymer composition. Requirement (1): 1.2≦A1 / A2≦1.5 A1 is a compound in which the silicon contained in the silicate has the composition formula SiO ２ SiO when expressed as ２ is the amount of substance (mol). A2 is a value obtained by dividing the total alkali metals M contained in the alkali solution containing the silicate by M ２ When O is formed, M ２ is the amount of O (mol).

2. The geopolymer composition of claim 1, wherein the shrinkage reducing agent comprises a compound represented by the following formula (5): Formula (5): R 12 O-(C 2 H 4 O) n -R 13 In formula (5), R 12 and R 13 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n represents an integer of 1 to 20, provided that when R 12 and R 13 are both hydrogen atoms, n represents an integer of 2 to 20.

3. 3. The geopolymer composition of claim 1 or claim 2, wherein the active filler comprises at least one of fly ash and ground granulated blast furnace slag.

4. A hardened geopolymer body which is a hardened product of the geopolymer composition according to any one of claims 1 to 3.

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