Geopolymer composition, geopolymer cured product, and method for producing geopolymer cured product

Abstract

Provided is a geopolymer composition comprising an active filler, an aggregate, an activator, a polycondensate-based dispersant that has polyalkylene glycol monophenyl ether as a partial structure, and water, wherein: the active filler contains coal ash and blast furnace slag fine powder; the ignition loss of the coal ash is not less than 3.0%; the added amount of the blast furnace slag fine powder is not less than two times the added amount of the coal ash; the w / b of the geopolymer composition (where w / b is represents the percent of (water added amount (mass%)) / (active filler total added amount (mass%))) is 30-37; and the added amount of silica fume with respect to the total mass of the active filler is less than 20 mass%.

Description

Geopolymer composition, hardened geopolymer body, and method for producing hardened geopolymer body

[0001] The present invention relates to a geopolymer composition, a hardened geopolymer, and a method for producing the hardened geopolymer.

[0002] Hardened materials such as concrete, mortar, artificial stone, and hardened building materials generally contain cement. However, cement releases a large amount of CO when fired. ２ Therefore, methods for producing hardened materials such as concrete and mortar that do not use cement and are environmentally friendly are attracting attention. In particular, methods for producing hardened materials using the geopolymer method are being actively researched.

[0003] In the geopolymer method, powders containing silicon and aluminum as the main components are used as binders to bond the powders together and produce artificial rocks. The hardened geopolymer formed by the geopolymer method is produced by causing a geopolymer reaction using an activated filler as an aluminosilicate source and an alkaline aqueous solution as an activator. Examples of activated fillers that can be used include natural products such as coal ash, kaolin, and clay, as well as silica fume and blast furnace slag. Of these activated fillers, coal ash is the most commonly used.

[0004] On the other hand, from the viewpoint of the ease of handling of geopolymer compositions at the manufacturing or construction site of hardened products, it is preferable that the geopolymer composition have good fluidity before hardening (see, for example, Patent Document 1). However, it is known that unburned carbon contained in coal ash adversely affects the fluidity of geopolymer compositions. Specifically, it is known that the higher the unburned carbon content in coal ash, the lower the fluidity of the geopolymer composition. For example, Patent Document 2 discloses a method for producing a geopolymer composition that includes a step of reducing the unburned carbon content of coal ash (specifically, fly ash). Specifically, Patent Document 2 describes a method for producing a geopolymer composition with high fluidity before hardening, which includes a fly ash production step in which a raw material containing unburned carbon is dispersed in water and the resulting slurry is subjected to flotation to produce fly ash with an unburned carbon content of 2% or less; a kneading step in which raw materials containing fly ash, ground blast furnace slag, and an alkali silica solution are kneaded to produce a geopolymer mixture; and a curing step in which the geopolymer mixture is hardened.

[0005] [Patent Document 1] JP 2020-26357 A [Patent Document 2] JP 2020-186143 A

[0006] The present invention aims to provide a geopolymer composition that can maintain good fluidity using a simple method, even when coal ash containing a large amount of unburned carbon is used as a raw material.

[0007] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention.

[0008] That is, the geopolymer composition according to the first aspect of the present invention is a geopolymer composition comprising an active filler, an aggregate, an activator, a polycondensate dispersant having a polyalkylene glycol monophenyl ether as a partial structure, and water, wherein the active filler comprises coal ash and ground granulated blast furnace slag, the ignition loss of the coal ash is 3.0% or more, the amount of the ground granulated blast furnace slag is at least twice the amount of the coal ash, and the w / b ratio of the geopolymer composition (w / b is the percentage of the amount of water (mass%) / the total amount of the active filler (mass%)) is 30 or more and 37 or less, and the amount of silica fume relative to the total mass of the active filler is less than 20 mass%.

[0009] A hardened geopolymer according to a second aspect of the present invention is obtained by hardening the geopolymer composition according to the first aspect.

[0010] A method for producing a hardened geopolymer according to a third aspect of the present invention includes kneading the geopolymer composition according to the first aspect and then curing it.

[0011] According to the method described in Patent Document 2, when preparing a geopolymer composition using coal ash with a high unburned carbon content as a raw material, an additional step is required to reduce the unburned carbon content. Therefore, the method described in Patent Document 2 is undesirable from the perspective of the cost and complexity of manufacturing a hardened product using a geopolymer composition. Therefore, it would be preferable to obtain a geopolymer composition with good fluidity before hardening without requiring an additional step, even if the coal ash used as a raw material has a high unburned carbon content.

[0012] For example, to solve the problem of poor fluidity of geopolymer compositions due to unburned carbon in coal ash, one possible solution is to increase the amount of water contained in the geopolymer composition to improve fluidity. However, if the amount of water is too high, the strength of the hardened geopolymer composition after hardening may be insufficient, or bleeding (material separation) may occur. Therefore, it is difficult to solve the problem of poor fluidity of geopolymer compositions due to unburned carbon in coal ash simply by adjusting the amount of water.

[0013] The inventors conducted extensive research into geopolymer compositions that can maintain good fluidity even when using coal ash containing a large amount of unburned carbon as a raw material. They focused on the ratio of the amount of ground blast furnace slag to the amount of coal ash, the percentage of (amount of water (mass%)) / (total amount of active filler (mass%)), and the amount of silica fume, and completed the present invention. Specifically, the percentage of (amount of water (mass%)) / (total amount of active filler (mass%)) is calculated using the formula (amount of water) / (total amount of active filler) x 100. Hereinafter, the percentage of (amount of water (mass%)) / (total amount of active filler (mass%)) is also referred to as the "percentage of the ratio of the amount of water to the total amount of active filler (w / b)."

[0014] Thus, according to the present invention, even when coal ash containing a large amount of unburned carbon is used as a raw material, it is possible to provide a geopolymer composition that can maintain good fluidity using a simple method.

[0015] In this specification, "water" means all water contained in (or blended with) the geopolymer composition, excluding solids. That is, as will be described in detail later, for example, when an activator, dispersant, etc. is used in the form of an aqueous solution and additional water is optionally added for the purpose of adjusting fluidity, "water" also includes water contained in the aqueous solution of the activator, water contained in the aqueous solution of the dispersant, and optionally added water.

[0016] In this specification, unless otherwise specified, "total active filler content (mass%)," "aggregate content (mass%)," "fine aggregate content (mass%)," "coarse aggregate content (mass%)," "activator content (mass%)," "dispersant content (mass%)," and "water content (mass%)" refer to the content (mass%) relative to the total mass of the geopolymer composition.

[0017] In this specification, "the amount of activator (% by mass)" means the amount of activator (% by mass) as a solid content, and "the amount of dispersant (% by mass)" means the amount of dispersant (% by mass) as a solid content. The amount of solid content (% by mass) contained in the aqueous solution of the activator or the aqueous solution of the dispersant can be determined using a moisture analyzer, as described in the Examples below.

[0018] In this specification, the "ignition loss (%) of coal ash" can be calculated by conducting an ignition loss test in accordance with JIS A 6201:2015. The ignition loss of coal ash is a standard amount of unburned carbon content in coal ash. For example, JIS A 6201:2015 specifies upper limits of the ignition loss for fly ash types I to IV as quality standards according to the intended use of fly ash for concrete.

[0019] In this specification, the "average Blaine value (cm) of coal ash" ２ / g) means the average specific surface area of ​​coal ash. In detail, as will be described in the Examples below, the "average Blaine value (cm ２ / g) is a value measured by a specific surface area test using a Blaine air permeation device in accordance with JIS R 5201:2015.

[0020] Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

[0021] 1. Geopolymer Composition The geopolymer composition in this embodiment includes an active filler, an aggregate, an activator, a polycondensate dispersant having a polyalkylene glycol monophenyl ether as a partial structure, and water. The active filler includes coal ash and blast furnace slag ground powder.

[0022] Furthermore, the geopolymer composition in this embodiment satisfies three conditions: (i) the amount of blast furnace slag powder mixed is at least twice the amount of coal ash mixed, (ii) the percentage w / b of the ratio of the amount of water mixed to the total amount of active filler is 30 to 37, and (iii) the amount of silica fume mixed to the total mass of active filler is less than 20% by mass. By having the geopolymer composition meet all three of these conditions, it is possible to obtain a geopolymer composition that can maintain good fluidity using a simple method, even when coal ash containing a large amount of unburned carbon is used as a raw material.

[0023] Below, the functions, amounts, etc. of each component contained in the geopolymer composition will be explained in detail.

[0024] Unless otherwise specified, the blending amount (mass%) of each component described below primarily refers to the blending amount when the geopolymer composition is used as a geopolymer concrete composition (including both fine and coarse aggregates as aggregates). However, the blending amount of each component described below can be adjusted as needed even when the geopolymer composition is used as a geopolymer mortar composition (including only fine aggregates as aggregates).

[0025] <Activated Filler> Activated filler is a powder containing aluminosilicate as its main component. Aluminosilicate is active against alkali. When an activator (described later) or water is added to the activated filler, the silicon and aluminum in the activated filler are partially dissolved or ionized. After dissolution, the silica component, which exists in a state close to a monomer in the alkaline silica solution, captures metal ions. As a result, a dehydration condensation reaction occurs, producing a hardened polymer compound (polymer), resulting in a hardened geopolymer composition.

[0026] In the geopolymer composition of this embodiment, the active filler is not particularly limited as long as it includes coal ash and ground granulated blast furnace slag. The coal ash may include coal ash that has been specially pretreated to ensure uniform quality (specifically, treatment to conform to the standard for fly ash for concrete specified in JIS A 6201:2015), or it may include coal ash that has not been specially pretreated. Coal ash that has not been specially pretreated contains a large amount of unburned carbon and therefore has a high loss on ignition. Therefore, if the coal ash contains coal ash that has not been specially pretreated, the effects of this embodiment can be more effectively achieved.

[0027] In addition to coal ash and ground granulated blast furnace slag, the active filler may contain one or more of any active fillers known to those skilled in the art that have the above-mentioned functions. The geopolymer composition of this embodiment may contain silica fume as an active filler, but it must satisfy the above-mentioned condition (iii) that the amount of silica fume mixed relative to the total mass of the active filler is less than 20 mass%. These active fillers will be described in detail below.

[0028] (Coal ash) Coal ash is mainly composed of silicon dioxide (SiO ２ ), alumina (Al ２ O ３ ) and the like. In this embodiment, the type of coal ash is not particularly limited. Specifically, as described above, the coal ash may include coal ash produced as an industrial by-product that has not been treated to conform to the standard for fly ash for concrete specified in JIS A 6201:2015 (hereinafter also referred to as "untreated coal ash"), or may include coal ash that has been subjected to such treatment, or may be a mixture of these coal ashes. Of these, the coal ash preferably includes untreated coal ash.

[0029] Untreated coal ash refers to coal ash that has not been subjected to any processing other than normal pulverization for transportation from the production site, or raw powder coal ash. Using untreated coal ash as an activated filler allows for efficient and effective utilization of untreated industrial by-product coal ash as a resource. Furthermore, production costs can be reduced. Such untreated coal ash can be obtained, for example, as an industrial by-product generated during coal combustion from thermal power plants, boilers, etc.

[0030] In this specification, "untreated coal ash" (or "coal ash that has not been treated to comply with the standard for fly ash for concrete specified in JIS A 6201:2015") means coal ash that has not been subjected to a crushing treatment and / or particle size adjustment (preferably particle size adjustment). Alternatively, for example, "untreated coal ash" means coal ash that has not been subjected to a crushing treatment and / or particle size adjustment (preferably particle size adjustment) to comply with the standard for fly ash for concrete specified in JIS A 6201:2015. ２ / g to 6000 cm ２ The "untreated coal ash" is coal ash having a Blaine specific surface area of ​​about 1 / g and not subjected to pulverization and / or particle size adjustment (preferably particle size adjustment). Alternatively, for example, "untreated coal ash" is, in other words, preferably coal ash produced as an industrial by-product from at least one of a thermal power plant and a boiler. Note that in one embodiment, the "untreated coal ash" may be untreated coal ash consisting solely of coal ash that does not comply with the standard for fly ash for concrete specified in JIS A 6201:2015, or may be untreated coal ash that partially contains coal ash that complies with the standard.

[0031] Specifically, coal ash includes, for example, fly ash captured from exhaust gas by a dust collector, bottom ash obtained by crushing lumps of ash at the bottom of a boiler, etc. Two or more types of coal ash, preferably untreated coal ash, may be used in combination.

[0032] In the geopolymer composition of this embodiment, the loss on ignition of the coal ash is 3.0% or more. Specifically, according to this embodiment, even if the raw material contains coal ash (for example, untreated coal ash) with a loss on ignition of 3.0% or more and a higher amount of unburned carbon than usual, by satisfying the three conditions (i) to (iii) described above, a geopolymer composition that can maintain good fluidity can be obtained.

[0033] The ignition loss of the coal ash is preferably 4.0% or more, more preferably 5.0% or more, even more preferably 6.0% or more, and particularly preferably a value selected from the group consisting of 7.0%, 8.0%, 9.0%, 10.0%, 11.0%, and 11.5% or more. The upper limit of the ignition loss of the coal ash is not particularly limited, but is, for example, about 30%.

[0034] The amount of coal ash relative to the total mass of the active filler is appropriately adjusted to satisfy the above-mentioned condition (i) that the amount of ground granulated blast furnace slag is at least twice the amount of coal ash. When the geopolymer composition satisfies the above-mentioned conditions (ii) and (iii), if the amount of ground granulated blast furnace slag is at least twice the amount of coal ash, the effect of improving fluidity due to the ground granulated blast furnace slag described below can be obtained.

[0035] Specifically, the amount of coal ash relative to the total mass of the activated filler is not particularly limited as long as the amount of ground granulated blast furnace slag described below can be ensured, but it is preferably 3% to 40% by mass. In particular, when the coal ash contains untreated coal ash, a coal ash content of 3% by mass or more relative to the total mass of the activated filler allows for the effective use of untreated coal ash, an industrial by-product, as a resource. As a result, a geopolymer composition that is environmentally and cost-effective can be obtained. Furthermore, when the coal ash content relative to the total mass of the activated filler is 40% by mass or less, the amount of ground granulated blast furnace slag, which contributes to the fluidity improvement effect, is sufficient. Therefore, a geopolymer composition that maintains good fluidity can be reliably obtained.

[0036] When the coal ash contains untreated coal ash, the amount of untreated coal ash relative to the total mass of the coal ash is not particularly limited, but is preferably 90 mass% or more, more preferably 95 mass% or more, and even more preferably 100 mass%.

[0037] (Ground granulated blast furnace slag) Ground granulated blast furnace slag contains calcium oxide (CaO), silicon dioxide (SiO ２ ), alumina (Al ２ O ３ ) etc.

[0038] Any ground granulated blast furnace slag known to those skilled in the art can be used as the ground granulated blast furnace slag. For example, ground granulated blast furnace slag can be obtained by pulverizing granulated blast furnace slag. Granulated blast furnace slag is obtained as a by-product when refining iron in a blast furnace. Alternatively, commercially available ground granulated blast furnace slag may be used. For example, commercially available ground granulated blast furnace slag that meets the 4000 standard of JIS A 6206:2013 can be used. Such commercially available ground granulated blast furnace slag includes, for example, "K-MENT" sold by Kobe Steel Slag Products Co., Ltd. and "ESMENT" manufactured by Nippon Steel Blast Furnace Cement Co., Ltd.

[0039] The amount of ground granulated blast furnace slag relative to the total mass of the active filler is appropriately adjusted to satisfy the aforementioned condition (i) that the amount of ground granulated blast furnace slag relative to the amount of coal ash is at least twice as much. When the geopolymer composition satisfies conditions (ii) and (iii), if the amount of ground granulated blast furnace slag relative to the amount of coal ash is at least twice as much, the fluidity of the geopolymer composition can be improved by using a large amount of ground granulated blast furnace slag. This is presumably because the particle size of the ground granulated blast furnace slag commonly used in this technical field is finer than that of coal ash. Specifically, when a large amount of ground granulated blast furnace slag with a fine particle size is added, the particle size distribution of the entire active filler becomes broader, which is thought to improve the fluidity of the composition.

[0040] Specifically, the amount of ground granulated blast furnace slag relative to the total mass of the active filler is preferably 30% to 90% by mass. When the amount of ground granulated blast furnace slag is 30% by mass or more, the amount of ground granulated blast furnace slag that contributes to the fluidity-improving effect is sufficient. As a result, a geopolymer composition that can maintain good fluidity can be reliably obtained. In addition, the greater the amount of ground granulated blast furnace slag, the easier it is to obtain a hardened body with the desired high strength in a short period of time. When the amount of ground granulated blast furnace slag is 90% by mass or less, the amount of coal ash can be ensured, and a decrease in fluidity due to the incorporation of excessive ground granulated blast furnace slag can be prevented.

[0041] The amount of ground granulated blast furnace slag relative to the total mass of the active filler is more preferably 40% by mass or more, and even more preferably 45% by mass or more, and more preferably 85% by mass or less, and even more preferably 80% by mass or less.

[0042] (Silica fume) Silica fume is a material that contains silicon dioxide (SiO ２ Specifically, silica fume is a highly pure silicon dioxide (SiO ２ ) amorphous spherical fine particles.

[0043] When silica fume is included as an active filler, any silica fume known to those skilled in the art can be used. For example, silica fume is obtained as a by-product of collecting dust in exhaust gas generated during the production of ferrosilicon, metallic silicon, electrolytic zirconia, etc. Alternatively, commercially available silica fume may be used.

[0044] Silica fume is generally known to have the function of increasing the fluidity of geopolymer compositions. However, if the geopolymer composition satisfies the above-mentioned conditions (i) and (ii), the amount of silica fume must be kept below a certain value.

[0045] Specifically, as described above, the geopolymer composition of this embodiment satisfies the condition (iii) that the amount of silica fume relative to the total mass of the active filler is less than 20% by mass. When the geopolymer composition satisfies the conditions (i) and (ii) above, if the amount of silica fume relative to the total mass of the active filler is less than 20% by mass, the fluidity of the geopolymer composition can be prevented from decreasing due to an excessive amount of silica fume. Specifically, the particle size of silica fume is significantly finer than that of coal ash and blast furnace slag powder. Therefore, by reducing the amount of silica fume, it is expected that the water absorption caused by the fine powder of excess silica fume can be prevented, thereby suppressing the fluidity of the geopolymer composition. Furthermore, because silica fume is expensive, reducing the amount of silica fume can also reduce the production cost of the geopolymer composition.

[0046] The amount of silica fume relative to the total mass of the active filler is preferably 18% by mass or less, more preferably 15% by mass or less, even more preferably 12% by mass or less, and particularly preferably 10% by mass or less. The lower limit of the amount of silica fume is not particularly limited. For example, the amount of silica fume relative to the total mass of the active filler may be 0% by mass.

[0047] (Other active fillers) Other active fillers that can be included in the geopolymer composition of this embodiment include, for example, red mud, feldspars, micas, zeolites, perlite, clay minerals, kaolin, metakaolin, sewage sludge, etc.

[0048] The total amount (mass%) of active filler relative to the total mass of the geopolymer composition is adjusted appropriately so as to satisfy the condition that the ratio of the amount of water to the total amount of active filler (w / b) is 30 or more and 37 or less.

[0049] When the geopolymer composition satisfies the above conditions (i) and (iii), if the ratio of the amount of water to the total amount of active filler (w / b) is 37 or less, the occurrence of bleeding due to excess water and the insufficient strength of the hardened product of the geopolymer composition can be avoided. From the viewpoint of more reliably avoiding the occurrence of bleeding and the insufficient strength of the hardened product, the ratio of the amount of water to the total amount of active filler (w / b) is preferably 36 or less, more preferably 35 or less.

[0050] When the geopolymer composition satisfies the above-mentioned conditions (i) and (iii), if the percentage w / b of the ratio of the amount of water to the total amount of active filler is 30 or more, a significant decrease in fluidity due to an extremely small amount of water can be prevented. From the viewpoint of more reliably avoiding a significant decrease in fluidity, the percentage w / b of the ratio of the amount of water to the total amount of active filler is preferably 30 or more, more preferably 31 or more, and even more preferably 32 or more.

[0051] The total amount (mass %) of active filler relative to the total mass of the geopolymer composition can be determined not only by the condition (ii) described above, but also by the ratio of the amount of activator aqueous solution in the geopolymer composition. Generally, the activator as a solid is used in the form of an aqueous solution. Specifically, for example, when an alkaline aqueous solution of approximately 6 mol / L to 10 mol / L is used as the activator aqueous solution, the ratio of the amount of activator aqueous solution to the total amount of active filler (i.e., activator aqueous solution (mass) / active filler (total mass)) is preferably 4% to 30%. In this case, if the activator aqueous solution (mass) / active filler (total mass) ratio is 4% or more, the dehydration condensation reaction of the active filler can be sufficiently generated, ultimately resulting in a geopolymer hardened body with sufficient strength. Furthermore, in this case, if the activator aqueous solution (mass) / active filler (total mass) ratio is 30% or less, false coagulation caused by an excessive amount of activator can be prevented.

[0052] Likewise, in this case, the ratio of the activator aqueous solution (by weight) to the active filler (total weight) is preferably 10% or more, and even more preferably 15% or more, and in this case, the ratio of the activator aqueous solution (by weight) to the active filler (total weight) is preferably 25% or less, and even more preferably 20% or less.

[0053] The preferred ratio may vary depending on the type and concentration of the activator solution, but the ratio of activator solution (mass) to active filler (total mass) may be adjusted as needed to ensure that the active filler reacts sufficiently and does not cause false coagulation.

[0054] In addition, the total amount (mass%) of active filler relative to the total mass of the geopolymer composition varies depending on the type of geopolymer hardened body, which is the final product. Therefore, the total amount of active filler can be adjusted appropriately to suit the type of geopolymer hardened body desired. For example, the total amount of active filler is approximately 20% to 60% by mass relative to the total mass of the geopolymer composition. Examples of types of geopolymer hardened bodies include concrete, mortar, etc., as mentioned above.

[0055] <Aggregate> Any aggregate known to those skilled in the art can be used as the aggregate. For example, commonly known aggregates used in the production of concrete, mortar, artificial stone, etc. can be used. That is, the geopolymer composition of this embodiment can be applied to both geopolymer concrete compositions containing fine aggregate and coarse aggregate, and geopolymer mortar compositions containing fine aggregate but not coarse aggregate.

[0056] At least 85% of the fine aggregate is 5 mm or less in diameter. At least 85% of the coarse aggregate is 5 mm or more in diameter. The type of aggregate may be selected appropriately depending on the intended use of the final product, the hardened geopolymer. For example, two or more types of aggregate may be used, such as a combination of fine and coarse aggregates.

[0057] Examples of fine aggregate include blast furnace slag fine aggregate and fine aggregate such as general silica sand, which is a natural aggregate. Of these, it is preferable to use blast furnace slag fine aggregate. Blast furnace slag fine aggregate has latent hydraulic properties. The latent hydraulic properties are due to the silicon dioxide (SiO ２ ), alumina (Al ２ O ３ ) and other factors, which produces hydrates, which increases the strength of the hardened product. Therefore, by using blast furnace slag fine aggregate as an aggregate, it is possible to increase the long-term strength of the final product, the hardened geopolymer.

[0058] Blast furnace slag fine aggregate is specified in JIS A 5011-1:2018. Alternatively, commercially available blast furnace slag fine aggregate may be used. Examples of commercially available blast furnace slag fine aggregate include "Shinko Sand" sold by Kobelco Slag Products Co., Ltd. and blast furnace slag fine aggregate manufactured by JFE Mineral Co., Ltd.

[0059] As the coarse aggregate, it is preferable to use blast furnace slag coarse aggregate made from blast furnace slag. When blast furnace slag coarse aggregate and / or the above-mentioned blast furnace slag fine aggregate are used as the aggregate, industrial by-products can be effectively utilized as resources, and a highly environmentally friendly geopolymer composition can be obtained. Furthermore, production costs can be reduced.

[0060] The amount of aggregate to be mixed is not particularly limited and can be adjusted according to the intended use of the hardened geopolymer body, which is the final product. For example, the amount of aggregate to be mixed is preferably 30% to 70% by mass. If the amount of aggregate to be mixed is 30% by mass or more, it becomes difficult for the aggregate and the geopolymer composition paste to separate, making it easier to form a uniform hardened body. If the amount of aggregate to be mixed is 70% by mass or less, it becomes easier to suppress the occurrence of bleeding.

[0061] The amount of aggregate is preferably 40% by weight or more, more preferably 50% by weight or more, and more preferably 65% ​​by weight or less, more preferably 60% by weight or less, based on the total weight of the geopolymer composition.

[0062] <Activator> The activator is a component that initiates polymerization through a dehydration condensation reaction of the activated filler. Typically, the activator as a solid is used in the form of an aqueous solution. Specifically, the aqueous solution of the activator is an alkaline solution that comes into contact with the aluminosilicate in the activated filler and dissolves silicon and aluminum. Therefore, from the perspective of causing a dehydration condensation reaction, the activator as a solid reduces the fluidity of the geopolymer composition over time after kneading. On the other hand, from the perspective of being used in the form of an aqueous solution, the aqueous solution of the activator also contributes to improving the fluidity of the geopolymer composition immediately after kneading.

[0063] The aqueous solution of the activator is not particularly limited as long as it is a commonly used one, and for example, an aqueous solution of sodium hydroxide, water glass (sodium silicate), potassium silicate, etc. may be used. Alternatively, a commercially available activator containing an alkali source may be used as the activator (in solid or aqueous solution form). Examples of such commercially available activators include the Mastercrete AC series manufactured by Pozzolith Solutions.

[0064] The concentration of the aqueous alkaline solution of the activator must be adjusted appropriately depending on the type and amount of the activator, but is preferably 4 mol / L to 12 mol / L, for example. When the concentration of the aqueous activator solution is 4 mol / L or more, the dehydration condensation reaction in the activated filler can be sufficiently induced. When the concentration of the aqueous activator solution is 12 mol / L or less, the generation of excessive heat of fusion due to high concentrations can be avoided.

[0065] The concentration of the alkaline aqueous solution, which is the aqueous solution of the activator, must be adjusted appropriately depending on the type and amount of the activator, but is preferably 5 mol / L or more, and more preferably 6 mol / L or more.The concentration of the alkaline aqueous solution, which is the aqueous solution of the activator, must be adjusted appropriately depending on the type and amount of the activator, but is more preferably 11 mol / L or less, and more preferably 10 mol / L or less.

[0066] As described above, when the activator is prepared in the form of an aqueous solution, the amount of water contained in the aqueous solution of the activator may be adjusted within an appropriate range so as to satisfy the above-mentioned condition (ii) that the ratio of the amount of water to the total amount of active filler, w / b, is 30 or more and 37 or less.

[0067] At the same time, as mentioned above, the amount of the activator aqueous solution can also be determined from the ratio of the total amount of active filler to the total mass of the geopolymer composition.

[0068] <Water> As mentioned above, water refers to all water contained in the geopolymer composition. In other words, in this specification, the "water content (mass%)" refers to the amount of water contained in the aqueous solution of the activator when the activator is in the form of a solid aqueous solution, the amount of water contained in the aqueous solution of the dispersant when the dispersant is in the form of a solid aqueous solution, the amount of water optionally added separately for the purpose of adjusting the fluidity of the geopolymer composition (hereinafter referred to as "externally added water"), and the amount of water optionally contained in other materials. The type of water is not particularly limited, and examples include tap water, ion-exchanged water, etc. The pH and temperature of the water are also arbitrary and can be adjusted to general values ​​as appropriate depending on the type and amount of each component contained in the geopolymer composition.

[0069] Water contributes to the fluidity of the geopolymer composition. As mentioned above, ensuring the fluidity of the geopolymer composition by adjusting only the amount of water is the lowest-cost and easiest way to maintain fluidity. However, excessively increasing the amount of water may cause bleeding or insufficient strength in the hardened geopolymer composition product. However, the geopolymer composition of this embodiment contains a polycondensate-based dispersant having a polyalkylene glycol monophenyl ether as a partial structure, as described below, as a dispersant. Therefore, compared to general geopolymer compositions, the amount of water required to ensure good fluidity can be reduced.

[0070] The amount of water (mass%) relative to the total mass of the geopolymer composition is not particularly limited as long as the ratio of the amount of water to the total amount of active filler (ii) (w / b) satisfies the condition of 30 to 37. For example, the amount of water may be adjusted within an appropriate range based on the total amount of active filler used as a raw material so as to satisfy the condition of 30 to 37.

[0071] More specifically, the amount of water is preferably 6.0% by mass to 10.0% by mass. The amount of water is more preferably 9.5% by mass or less, even more preferably 9.0% by mass or less, and particularly preferably 8.5% by mass or less. The amount of water is more preferably 6.5% by mass or more, even more preferably 7.0% by mass or more, and particularly preferably 7.5% by mass or more.

[0072] <Dispersant> The geopolymer composition in this embodiment contains a polycondensate-based dispersant having a polyalkylene glycol monophenyl ether as a partial structure. Specifically, this solid dispersant is often used as a polycondensate-based dispersant having a polyalkylene glycol monophenyl ether as a partial structure in the form of an aqueous solution.

[0073] The inclusion of this dispersant in the geopolymer composition inhibits contact between particles in the geopolymer composition. As a result, the hardening reaction of the geopolymer composition can be slowed down. In addition, the hardening reaction retardation effect of this dispersant disappears within a few hours. Therefore, when a geopolymer composition contains this dispersant, it can achieve both good fluidity maintenance over a long period of time and subsequent strength development.

[0074] In this specification, the term "polycondensate dispersant having a polyalkylene glycol monophenyl ether as a partial structure" is not particularly limited as long as it is a polymer having the above-mentioned effect and a specified structure. Examples of such dispersants include polymers containing polycondensates containing the following structural units A, B, C, and D.

[0075] Structural unit A: At least one polyethylene glycol monophenyl ether represented by the following formula (1): [Chemical Formula 1] [wherein, m is an integer of 3 to 280]

[0076] Structural unit B: a cyclic compound having at least one hydroxyl group and a derivative thereof, for example, at least one aromatic compound selected from the group consisting of benzene-1,2-diol, benzene-1,2,3-triol, 2-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, 3-hydroxyphthalic acid, 2,3-dihydroxybenzenesulfonic acid, 3,4-dihydroxybenzenesulfonic acid, 1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,2-dihydroxynaphthalene-5-sulfonic acid, 1,2-dihydroxynaphthalene-6-sulfonic acid, 2,3-dihydroxynaphthalene-5-sulfonic acid, 2,3-dihydroxynaphthalene-6-sulfonic acid, and mixtures thereof.

[0077] Structural unit C: phenol, polyethylene glycol monophenyl ether having 1 or 2 ethylene oxide repeating units, or a phenoxyethyl derivative containing a phosphate or phosphonate, such as at least one other aromatic compound selected from the group consisting of phenol, 2-phenoxyethanol, 2-phenoxyethyl phosphate, 2-phenoxyethyl phosphonate, 2-phenoxyacetic acid, 2-(2-phenoxyethoxy)ethanol, 2-(2-phenoxyethoxy)ethyl phosphate, 2-(2-phenoxyethoxy)ethyl phosphonate, 2-[4-(2-hydroxyethoxy)phenoxy]ethyl phosphate, 2-[4-(2-hydroxyethoxy)phenoxy]ethyl phosphonate, 2-[4-(2-phosphonatooxyethoxy)phenoxy]ethyl phosphate, 2-[4-(2-phosphonatooxyethoxy)phenoxy]ethyl phosphonate, methoxyphenol, and mixtures thereof.

[0078] Structural unit D: aldehydes, for example, at least one aldehyde selected from the group consisting of formaldehyde, paraformaldehyde, glyoxylic acid, benzaldehyde, benzaldehyde sulfonic acid, benzaldehyde disulfonic acid, vanillin, isovanillin, and mixtures thereof.

[0079] The solid content of the dispersant is preferably 0.05% to 0.25% by mass. When the solid content of the dispersant is 0.05% by mass or more, the above-mentioned dispersant action can be effectively exerted, and high fluidity over a long period of time and high strength can be achieved in a short period of time. When the solid content of the dispersant is 0.25% by mass or less, separation and bleeding of the geopolymer composition due to the addition of excessive dispersant can be suppressed.

[0080] The solid content of the dispersant is more preferably 0.06% by mass or more, even more preferably 0.07% by mass or more, and particularly preferably 0.08% by mass or more, and more preferably 0.23% by mass or less, even more preferably 0.21% by mass or less, and particularly preferably 0.20% by mass or less.

[0081] <Other Materials> The geopolymer composition in this embodiment may contain any material that can be generally added as a raw material for mortar, concrete, etc., as long as it does not impair the effect of maintaining good fluidity. For example, it may contain an inert filler, which is a powder that is not active against alkali, various additives, etc. Examples of inert fillers include cement and calcium carbonate. The various additives are not particularly limited, but include conventionally known components such as fluidizers, shrinkage reducing agents, rust inhibitors, waterproofing agents, antifoaming agents, dust reducing agents, and pigments.

[0082] 2. Method for Preparing Geopolymer Composition The geopolymer composition of this embodiment can be prepared by any method known to those skilled in the art. For example, the method for preparing the geopolymer composition includes a powder mixing step and a subsequent kneading step. In the powder mixing step, the main powder raw materials, active filler (e.g., activated filler including coal ash, blast furnace slag powder, and silica fume) and aggregate (e.g., fine aggregate and coarse aggregate), are mixed in a predetermined blending amount. In the subsequent kneading step, externally added water and an activator and dispersant in aqueous solution are further added to the powder mixture in a predetermined blending amount, and the mixture is mixed and kneaded. The mixing and kneading methods are not particularly limited, and any method known to those skilled in the art using a mixer or the like may be used.

[0083] In addition, in the method for preparing a geopolymer composition, a powder mixture containing the main powder raw materials, active filler (e.g., activated filler including coal ash, blast furnace slag powder, and silica fume), aggregate (e.g., fine aggregate and coarse aggregate), activator, and dispersant, may be prepared in advance and used as a premixed geopolymer composition. Specifically, prior to construction, work, etc., water is added to the premixed geopolymer composition in a predetermined amount, followed by mixing and kneading. This allows for easy on-site preparation of any desired geopolymer composition. Alternatively, when the activator and / or dispersant are prepared in the form of an aqueous solution, a powder mixture may be prepared in advance by adding and mixing the active filler and aggregate, which are materials other than the activator aqueous solution and / or the dispersant aqueous solution, in predetermined amounts, and the prepared powder mixture may be used as a premixed geopolymer composition. In this case, the activator aqueous solution and / or dispersant aqueous solution, and optionally externally added water, are added to the premix geopolymer composition in predetermined amounts and mixed and kneaded prior to construction, work, etc. Alternatively, if the activator and / or dispersant is prepared in advance in the form of an aqueous solution, the active filler and aggregate, and a portion of one or more of the aforementioned aqueous solutions may be added and mixed in predetermined amounts to form a premix geopolymer composition or its precursor. In this case, the remaining activator aqueous solution and / or dispersant aqueous solution, and optionally externally added water, are added to the premix geopolymer composition or its precursor in predetermined amounts and mixed and kneaded prior to construction, work, etc.

[0084] According to the geopolymer composition of this embodiment, good fluidity can be maintained using a simple method, even when coal ash containing a large amount of unburned carbon is used as a raw material. Maintaining good fluidity allows the geopolymer composition to be easily handled at the manufacturing site of the hardened product. In addition, according to the geopolymer composition of this embodiment, no additional process is required to reduce the unburned carbon in the coal ash. A geopolymer composition that maintains good fluidity can be obtained simply by adjusting the blending amounts of each component in the geopolymer composition. Therefore, this is extremely advantageous industrially from the perspective of reducing the manufacturing costs of hardened geopolymer compositions.

[0085] 3. Geopolymer hardened body and method for manufacturing the geopolymer hardened body The geopolymer hardened body in this embodiment is obtained by hardening the geopolymer composition in the above-mentioned embodiment. The geopolymer hardened body has any shape that can be formed by any molding method, construction method, etc.

[0086] The hardened geopolymer material is preferably concrete or mortar, but is not particularly limited thereto. More specifically, the hardened geopolymer material includes, for example, road or bank blocks, blocks for storm drains or irrigation channels, tiles, bricks, sewer pipes, precast products such as piles, poles, and sleepers, cast-in-place products such as cast-in-place concrete, shotcrete, concrete repair, and dam concrete.

[0087] The method for producing a hardened geopolymer in this embodiment includes mixing and curing the geopolymer composition in the above-described embodiment. Specifically, the mixed geopolymer composition is first molded or applied using any method known to those skilled in the art, such as molding using a formwork, troweling in plastering work, spraying, or pasting. The molded or applied geopolymer composition is then cured using any curing method known to those skilled in the art. As a result, a hardened geopolymer can finally be obtained.

[0088] As a specific curing method, the curing is preferably one or more of air curing and sealed curing. As described above, the geopolymer composition of this embodiment contains a polycondensate dispersant having a polyalkylene glycol monophenyl ether as a partial structure as a dispersant. Therefore, compared to general geopolymer compositions, the amount of water can be reduced. Therefore, without performing complex processes such as steam curing, which are expensive and have a large environmental impact, a geopolymer hardened body with sufficient strength can be produced in a shorter time than usual by, for example, air curing and sealed curing.

[0089] In addition, in order to obtain a high-strength geopolymer hardened body in a shorter period of time, curing may be performed by combining one or more of air curing and sealed curing with steam curing (preferably short-term steam curing).

[0090] In addition, when producing a hardened geopolymer body using a formwork, it is preferable to include applying a release agent or the like to the formwork in advance. The release agent is not particularly limited as long as it is any release agent known to those skilled in the art that imparts release properties to the hardened geopolymer body.

[0091] As described above, this specification discloses various aspects of the technology, the main aspects of which are summarized below.

[0092] The geopolymer composition according to the first aspect of the present invention is a geopolymer composition comprising an active filler, an aggregate, an activator, a polycondensate dispersant having a polyalkylene glycol monophenyl ether as a partial structure, and water, wherein the active filler comprises coal ash and ground granulated blast furnace slag, the ignition loss of the coal ash is 3.0% or more, the amount of the ground granulated blast furnace slag is at least twice the amount of the coal ash, and the w / b of the geopolymer composition (w / b is the percentage of the amount of water (mass%) / (the total amount of the active filler (mass%))) is 30 or more and 37 or less, and the amount of silica fume relative to the total mass of the active filler is less than 20 mass%.

[0093] A geopolymer composition according to a second aspect of the present invention is the geopolymer composition according to the first aspect, wherein the coal ash is not treated to comply with the standard for fly ash for concrete specified in JIS A 6201:2015.

[0094] A geopolymer composition according to a third aspect of the present invention is the geopolymer composition according to the first or second aspect, wherein the coal ash has an ignition loss of 8% or more.

[0095] A geopolymer composition according to a fourth aspect of the present invention is a geopolymer composition according to any one of the first to third aspects, wherein the amount of silica fume relative to the total mass of the active filler is 15% by mass or less.

[0096] The hardened geopolymer according to the fifth aspect of the present invention is obtained by hardening the geopolymer composition according to any one of the first to fourth aspects.

[0097] A method for producing a geopolymer hardened body according to a sixth aspect of the present invention includes kneading a geopolymer composition according to any one of the first to fourth aspects and then curing it.

[0098] A method for producing a hardened geopolymer according to a seventh aspect of the present invention is the method for producing a hardened geopolymer according to the sixth aspect, wherein the curing is one or more of air curing and sealed curing.

[0099] A method for producing a hardened geopolymer according to an eighth aspect of the present invention is a method for producing a hardened geopolymer according to the sixth or seventh aspect, wherein the hardened geopolymer is mortar or concrete.

[0100] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0101] In this example, we investigated the detailed relationship between the fluidity of a geopolymer composition containing unburned carbon in the raw coal ash, the amount of ground blast furnace slag powder relative to the amount of coal ash, the percentage ratio of the amount of water to the total amount of active filler (w / b), and the amount of silica fume. Specifically, we first prepared various geopolymer compositions by varying the amount of unburned carbon, coal ash, and water contained in the raw coal ash. We then conducted fluidity and bleeding tests on the geopolymer compositions to evaluate them.

[0102] In this example, the "ignition loss (%) of coal ash," which is a criterion for the unburned carbon content in coal ash, was calculated by conducting an ignition loss test in accordance with JIS A 6201:2015.

[0103] In this example, the average Blaine value (cm ２ / g) was measured by a specific surface area test in accordance with JIS R 5201:2015 using a Blaine air permeability device (manufactured by Daiken Rikagaku Kikai Co., Ltd., "Blaine air permeability particle size meter").

[0104] First, the raw materials of the geopolymer compositions used in each experimental example and each comparative example and their preparation methods will be described in detail below.

[0105] [Raw materials for geopolymer composition] The raw materials for the geopolymer composition used in each experimental example and each comparative example are as follows: Coal ash 1 (untreated coal ash (coal ash as an industrial by-product collected at thermal power plants, specifically fly ash captured by an electrostatic precipitator)): Ignition loss 11.7%, average Blaine value 4670 cm ２ / g Coal ash 2 (untreated coal ash (coal ash as an industrial by-product collected at thermal power plants, specifically fly ash captured by an electrostatic precipitator)): Ignition loss 4.0%, average Blaine value 4310 cm ２ / g Finely ground blast furnace slag: "K-MENT" (specific surface area 4700 cm) manufactured by Kobe Steel Slag Products Co., Ltd. ２ / g) Silica fume: "Mastercrete SF 5000" manufactured by Pozzolith Solutions, bulk density: 2.2 g / cm ３Fine aggregate (blast furnace slag fine aggregate): "Shinko Sand" manufactured by Kobe Steel Slag Products Co., Ltd. (maximum particle size 2.5 mm, sieve passing mass fraction 55% when the nominal size of the sieve is 0.6 mm) Coarse aggregate (cooled blast furnace slag) (only in Example 2): cooled blast furnace slag adjusted to a particle size of 5 mm to 20 mm Coarse aggregate (Examples other than Example 2 and each comparative example): hard crushed sandstone from Omi (maximum size 20 mm, surface dry density 2.65 g / cm ３ ) Externally added water: tap water Aqueous solution of activator: "Mastercrete AC 5025" manufactured by Pozzolith Solutions Aqueous solution of dispersant: Aqueous solution of the compound described in Example 5 of Japanese Patent No. 6290176 (This aqueous solution of the compound can be prepared by the following method. First, 300 parts by weight of poly(ethylene oxide) monophenyl ether (average molecular weight 2000 g / mol), 46.2 parts by weight of 3,4-dihydroxybenzoic acid, 33 parts by weight of 2-phenoxyethyl phosphate, and 19.5 parts by weight of paraformaldehyde are added to a heatable reactor equipped with a stirrer and a metering pump. 9 parts by weight are charged under nitrogen at 90°C. The reaction mixture is then heated to 110°C with stirring, and 41 parts by weight of methanesulfonic acid (70%) are then added within 25 minutes, so that the reaction temperature does not exceed 115°C. After metering, the reaction mixture is stirred for a further 2.5 hours at 110°C. The reaction mixture is then cooled and mixed with 350 parts by weight of water, and the mixture is heated for 30 minutes at 100°C. Finally, it is neutralized with 50% caustic soda solution to a pH value of about 7.0.

[0106] [Method for preparing geopolymer composition] The above raw materials were mixed in the respective amounts shown in Tables 1 and 2 below (Table 1 shows the amount (mass%) relative to the total mass of the composition, and Table 2 shows the amount (mass%) relative to the total mass of the active filler), and geopolymer compositions in Examples 1 to 7 and Comparative Examples 1 to 8 were prepared. Specifically, first, coal ash 1 or coal ash 2, blast furnace slag powder, and silica fume were mixed as active fillers in the respective amounts shown in Table 2 below. Next, fine aggregate or both fine and coarse aggregates were added to this mixed powder in the respective amounts shown in Table 1 and mixed. Finally, an aqueous solution of the activator, an aqueous solution of the dispersant, and externally added water were added to the mixture and kneaded using a forced twin-shaft mixer. The amounts of the activator and dispersant are shown in Table 1 below as solids (mass%). The amount of water shown in Table 1 below is the total amount (mass%) of externally added water, water contained in the aqueous activator solution, and water contained in the aqueous dispersant solution. Specifically, the amount of externally added water was adjusted and added based on the total amount (mass%) of water contained in the aqueous activator solution and water contained in the aqueous dispersant solution so that the amount of water (total amount) would be the amount shown in Table 1.

[0107] Table 1 below also shows the percentage (w / b) of the ratio of the amount of water to the total amount of active filler. The amount of water (mass%) required to determine the w / b ratio was calculated by adding the amount (mass%) of externally added water, the amount (mass%) of water contained in the activator aqueous solution, and the amount (mass%) of water contained in the dispersant aqueous solution. The amount (mass%) of water contained in the activator aqueous solution or the dispersant aqueous solution was determined by subtracting the solids content (mass%) of each solution from the amount (mass%) of the activator aqueous solution or the dispersant aqueous solution. The solids content (mass%) was determined by evaporating each solution to dryness at 110°C for approximately 15 minutes using an A&D moisture analyzer (MX-50). Table 2 also shows the ratio of the amount of ground granulated blast furnace slag to the amount of coal ash.

[0108] [Table 1]

[0109] [Table 2]

[0110] Next, using each geopolymer composition prepared as described above, a fluidity test and a bleeding test were performed to evaluate the geopolymer composition. The test method and test results are described in detail below.

[0111] [Geopolymer Composition Fluidity Test] The fluidity of the geopolymer composition (geopolymer concrete composition) was measured in accordance with the concrete slump flow test specified in JIS A 1150:2020. Specifically, the diameter of the concrete expanded from the start of slump cone lifting until the stop was confirmed, i.e., slump flow (cm), and the time to reach 50 cm of flow (T50 (seconds)) were measured. If the slump flow was 65 cm or more and T50 maintained high fluidity within 10 seconds, the fluidity of the geopolymer composition was rated as "A" (good). If these measurement conditions were not met, the fluidity of the geopolymer composition was rated as "B" (not good).

[0112] [Geopolymer Composition Bleeding Test] The geopolymer composition bleeding test was performed as follows. After kneading the raw materials of the geopolymer composition with a total volume of 1.5 L, the kneaded composition was left for 1 hour. After 1 hour, the water floating on the surface of the left-standing composition was extracted with a dropper. Then, the volume of the extracted water was measured using a measuring cylinder, and the degree of bleeding was evaluated.

[0113] The results of the fluidity test and the bleeding test for the geopolymer compositions (geopolymer concrete compositions) of each experimental example and each comparative example are summarized in Table 3 below. The geopolymer compositions of Comparative Examples 1 and 2 were found to have bleeding in the first place, so their fluidity was deemed unmeasurable.

[0114] [Table 3]

[0115] [Discussion] As shown in Table 3 above, the geopolymer compositions of Examples 1 to 7 maintained good fluidity regardless of whether coal ash with an ignition loss of 11.7% or 4.0% was used as a raw material. This is thought to be because, as shown in Tables 1 and 2 above, the geopolymer compositions of Examples 1 to 7 satisfy all three of the above-mentioned conditions (i) to (iii).

[0116] On the other hand, as shown in Table 3 above, bleeding occurred in the geopolymer compositions of Comparative Examples 1 and 2. This is because the geopolymer compositions of Comparative Examples 1 and 2 met the above-mentioned conditions (i) and (iii), but the amount of water blended was large, and the ratio of the amount of water blended to the total amount of active filler (w / b) exceeded 37. This is thought to be largely due to this.

[0117] As shown in Table 3 above, the geopolymer compositions of Comparative Examples 3, 4, and 6 did not exhibit good fluidity. This is because the geopolymer compositions of Comparative Examples 3, 4, and 6 met the above-mentioned conditions (ii) and (iii), but the amount of ground blast furnace slag powder mixed relative to the amount of coal ash mixed was small, which is assumed to have adversely affected the fluidity of the composition.

[0118] As shown in Table 3 above, the fluidity of the geopolymer compositions of Comparative Examples 5 and 7 was significantly reduced. This is because the geopolymer compositions of Comparative Examples 5 and 7 met the above-mentioned conditions (i) and (ii), but the amount of silica fume blended was significantly high, which is assumed to have had a significant adverse effect on the fluidity of the composition.

[0119] As shown in Table 3 above, the geopolymer composition of Comparative Example 8 did not exhibit good fluidity. This is because, although the geopolymer composition of Comparative Example 8 met the above-mentioned conditions (i) and (iii), the amount of water blended was small, and the ratio of the amount of water blended to the total amount of active filler (w / b) was less than 30, which is assumed to have had a significant adverse effect on the fluidity of the composition.

[0120] From the above results, regardless of the quality of the coal ash with respect to the ignition loss (unburned carbon content), the ratio of the amount of blast furnace slag powder to the amount of coal ash, the percentage w / b of the ratio of the amount of water to the total amount of active filler, and the silica fume to the total mass of the active filler. By adjusting these values, it can be seen that good fluidity of the geopolymer composition can be maintained.

[0121] This application is based on Japanese Patent Application No. 2024-055270 filed on March 29, 2024, the contents of which are incorporated herein by reference.

[0122] The embodiments and examples disclosed herein should be understood to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0123] According to an embodiment of the present invention, a geopolymer composition that can maintain good fluidity using a simple method is provided, even when coal ash containing a large amount of unburned carbon is used as a raw material. Therefore, it is industrially very preferable from the viewpoint of reducing production costs, etc.

Claims

A geopolymer composition comprising an active filler, aggregate, an activator, a polycondensate dispersant having a polyalkylene glycol monophenyl ether as a partial structure, and water, wherein the active filler comprises coal ash and ground granulated blast furnace slag, the coal ash has an ignition loss of 3.0% or more, the amount of ground granulated blast furnace slag is at least twice the amount of the coal ash, and the w / b ratio of the geopolymer composition (w / b represents the percentage of (the amount of water (% by mass)) / (the total amount of the active filler (% by mass))) is 30 to 37, and the amount of silica fume relative to the total mass of the active filler is less than 20% by mass.

2. The geopolymer composition of claim 1, wherein the coal ash has a loss on ignition of 8% or more. 　 The geopolymer composition of claim 1, wherein the amount of silica fume relative to the total mass of the active filler is 15% by mass or less. 　 A hardened geopolymer obtained by hardening the geopolymer composition according to any one of claims 1 to 3. 　 A method for producing a hardened geopolymer, comprising kneading the geopolymer composition according to any one of claims 1 to 3 and then curing it.

6. The method for producing a hardened geopolymer body according to claim 5, wherein the curing is one or more of air curing and sealed curing. 　 The method for producing a hardened geopolymer according to claim 5, wherein the hardened geopolymer is mortar or concrete.

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