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

Abstract

This geopolymer composition contains: an active filler containing at least a blast-furnace slag fine powder; and sodium silicate as an activator. The sodium silicate is sodium orthosilicate or anhydrous sodium metasilicate. When the sodium silicate is sodium orthosilicate, the content of the sodium orthosilicate is 2-50 parts by weight with respect to 100 parts by weight of the active filler. When the sodium silicate is anhydrous sodium metasilicate, the content of the anhydrous sodium metasilicate is 10-30 parts by weight with respect to 100 parts by weight of the active filler.

Description

[Technical Field]

[0001] The present invention relates to a geopolymer composition, a hardened body obtained from this composition, and a method for producing this hardened body. [Background technology]

[0002] Geopolymers are attracting attention worldwide as a new binder to replace Portland cement. In Japan, a mixture of fly ash and ground granulated blast furnace slag is often used as the main raw materials for geopolymers.

[0003] The amount of CO2 emissions from geopolymers varies depending on the evaluation method, but when fly ash is used as the main raw material, it is said to have an approximately 80% CO2 reduction effect compared to Portland cement. Also, when fly ash and ground granulated blast furnace slag are used in combination, it is said to have a 65-70% CO2 reduction effect.

[0004] Geopolymers have superior acid resistance and heat resistance (fire resistance) compared to hardened Portland cement. Geopolymers are also less susceptible to alkali-silica reactions, and their solidification mechanism has been found to have the ability to fix harmful substances such as radioactive materials, making them highly anticipated for use.

[0005] Prior art related to the present application is exemplified by Patent Document 1. Patent Document 1 discloses a technique for obtaining a hardened body from a geopolymer composition containing an active filler such as fly ash, blast furnace slag, or sewage incineration sludge, and water glass as an alkaline activator. This prior document describes that a high-strength hardened body can be obtained by using sodium metasilicate powder as the water glass.

[0006] Patent Document 2 discloses a geopolymer composition containing calcium aluminates as a hardening accelerator. Patent Document 3 discloses a geopolymer composition in which the volume ratio of ground granulated blast furnace slag to the mixed powder of ground granulated blast furnace slag and fly ash is adjusted to 35 to 80%. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2008-239446 [Patent Document 2] Japanese Patent Publication No. 2018-087139 [Patent Document 3] Japanese Patent Publication No. 2021-066613 Summary of the Invention [Problem to be solved by the invention]

[0008] However, Patent Documents 1 to 3 use highly alkaline solutions, such as potassium hydroxide solution and sodium hydroxide solution, to obtain a hardened body. Therefore, to protect workers from risks such as alkali burns and blindness, careful handling is required during work. Furthermore, if workers make an error in measuring the highly alkaline solution during on-site preparation, the hardened body is likely to be of poor quality. In this regard, powdering all ingredients except water, premixing them, and packaging them in bags simplifies on-site preparation, thereby reducing the occurrence of measuring errors. However, because alkalis are highly deliquescent, it is practically impossible to store a premix containing powdered alkali.

[0009] One object of the present invention is to provide a geopolymer composition that has fewer handling restrictions and can simplify the work of adjusting the hardened body at the work site, and related technologies. [Means for solving the problem]

[0010] Sodium silicate is also called water glass. Many compounds collectively referred to as water glass are in liquid form, but only sodium metasilicate and sodium orthosilicate are in powder form. The inventors conducted research focusing on sodium orthosilicate and anhydrous sodium metasilicate among the powdered sodium silicates. They then discovered by chance that the use of these sodium silicates allows the condensation reaction of geopolymers to proceed even in the absence of a highly alkaline solution.

[0011] Sodium orthosilicate reacts with water to produce sodium metasilicate and sodium hydroxide. Therefore, if sodium orthosilicate is used as an activator, there is no need to add a highly alkaline solution to obtain a hardened body. Also, anhydrous sodium metasilicate reacts with water to produce water glass and sodium hydroxide. Therefore, if anhydrous sodium metasilicate is used as an activator, like sodium orthosilicate, there is no need to add a highly alkaline solution.

[0012] Therefore, the inventors conducted further research and found that by adjusting the blending ratio of these sodium silicates within an appropriate range, the hardened product obtained by adding water is extremely excellent in practical use, and thus completed the present invention.

[0013] The first invention is a geopolymer composition having the following characteristics: The geopolymer composition includes an active filler including at least ground granulated blast furnace slag and sodium silicate as an activator. The sodium silicate is sodium orthosilicate. In be. The aforementioned The content of sodium orthosilicate per 100 parts by weight of the active filler 15~50 Parts by weight.

[0014] The second invention further has the following features in addition to the first invention. The content of sodium orthosilicate The upper limit is 45 Parts by weight.

[0015] The third invention further has the following characteristics in addition to the first or second invention. The ground granulated blast furnace slag has a Blaine specific surface area in the range of 3000 to 4000 cm 2 / g standard surface area powder and Blaine specific surface area range of 6000-10000 cm 2 / g of high surface area powder .

[0016] The fourth invention is the first invention. or invention 2 It also has the following features: The active filler further comprises a pozzolanic material. .

[0017] The fifth invention is the first invention. or invention 2 It also has the following features: The active filler does not include fly ash. .

[0018] The sixth invention is the first invention. or invention 2 It also has the following features: The geopolymer composition has a setting time of 10 minutes or more and 1 hour 52 minutes or less, measured according to the method described in the setting test of JIS R 5201, after being mixed with water as a hardener. .

[0019] The seventh invention is the first or invention 2 It also has the following features: The geopolymer composition further comprises citric acid as a set modifier. .

[0020] The eighth invention is a geopolymer hardened body having the following characteristics. The hardened geopolymer body contains an active filler containing at least ground granulated blast furnace slag, sodium silicate as an activator, and water as a hardener. The sodium silicate is sodium orthosilicate. In be. The aforementioned The content of sodium orthosilicate per 100 parts by weight of the active filler 15~50 Parts by weight.

[0021] The ninth invention is a method for producing a hardened geopolymer body, and has the following characteristics. The manufacturing method includes: Water is added to a geopolymer composition containing an active filler containing at least ground blast furnace slag and sodium silicate as an activator, and the composition is kneaded. Kneading The process and The kneaded product obtained in the kneading step is cured at room temperature for 3 hours or more. Health care The process and Includes. The sodium silicate is sodium orthosilicate. In be. The aforementioned The content of sodium orthosilicate per 100 parts by weight of the active filler 15~50 Parts by weight. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram showing a reaction formula between sodium orthosilicate and water. [Figure 2] FIG. 1 is a diagram showing a reaction formula between anhydrous sodium metasilicate and water. [Figure 3] 1 is a flowchart showing an example of a method for producing a hardened geopolymer body. DETAILED DESCRIPTION OF THE INVENTION

[0023] The embodiments of the present invention are described in detail below. In this specification, "parts by weight" refers to a ratio based on the weight of the active filler. When a numerical range is expressed using "to", the range is inclusive of both ends of the range.

[0024] 1. Geopolymer composition The geopolymer composition according to the embodiment comprises an active filler comprising at least ground granulated blast furnace slag and sodium silicate as an active agent.

[0025] 1-1. Active filler Ground granulated blast furnace slag (hereinafter referred to as "BFS") used as an activated filler is a by-product obtained during the refining of iron in a blast furnace. The main components of BFS are calcium oxide (CaO), silicon dioxide (SiO2), alumina (Al2O3), etc., and its quality is specified in JIS A 6206. BFS is an amorphous substance with latent hydraulic properties, and the calcium component contained in it reacts in the geopolymer composition to produce calcium silicate hydrate (CSH), which then hardens.

[0026] BFS are classified based on the range of Blaine specific surface areas, which range from 2750 cm 2 / g or more 3500cm 2 / g or less, 3500cm 2 / g or more 5000cm 2 / g, less than 5000cm 2 / g or more 7000cm 2 / g and less than 7000 cm 2 / g or more 10000cm 2 The BFS preferably used as the active filler has a Blaine specific surface area of ​​3000 to 4500 cm 2 / g standard surface area powder and Blaine specific surface area 6000-10000cm 2 These BFS can be used alone or together.

[0027] The active filler "including at least BFS" means that the geopolymer composition according to the embodiment may contain active fillers other than BFS. Examples of such active fillers include pozzolanic substances. In this specification, the term "pozzolanic substance" refers to substances other than BFS that react with the calcium component contained therein to produce calcium silicate hydrate. Examples of pozzolanic substances include fly ash, metakaolin, silica fume, pulp sludge incineration ash, sewage sludge incineration ash, and waste glass powder. These pozzolanic substances may be used alone or simultaneously.

[0028] An example of a preferred pozzolanic substance to be used in combination with BFS is fly ash (hereinafter also referred to as "FA"). FA is coal ash generated during coal combustion at coal-fired power plants and is collected from exhaust gas using a dust collector. The main components of FA are silicon dioxide, alumina, etc. JIS A 6201 classifies FA into types I to IV based on particle size and flow value. Preferred AF to be used in combination with BFS include types I and II, which have a fine particle size and are highly reactive.

[0029] When BFS and an active filler other than BFS are used in combination, the amount of the active filler is not particularly limited and can be adjusted appropriately depending on the application of the hardened geopolymer and the desired mechanical properties, such as compressive strength, to be imparted to the hardened geopolymer. When BFS and an active filler other than BFS are used in combination, the amount of the active filler is, for example, 10 to 200 parts by weight per 100 parts by weight of BFS. In another example, the amount of the active filler other than BFS is 100 to 200 parts by weight per 100 parts by weight of BFS. In yet another example, the amount of the active filler other than BFS is 10 to 100 parts by weight per 100 parts by weight of BFS.

[0030] 1-2. Activator The sodium silicate used as an activator is either sodium orthosilicate or anhydrous sodium metasilicate. Sodium silicate is also called water glass, and many compounds collectively referred to as water glass are in liquid form. For example, sodium silicates No. 1 to No. 3 specified in JIS K 1408 are all liquid. On the other hand, sodium metasilicate and sodium orthosilicate are in powder form. Sodium metasilicate is classified into three types: nonahydrate, pentahydrate, and anhydrous salts, depending on the number of water molecules present. The sodium metametasilicate used as an activator is an anhydrous salt. Sodium orthosilicate also exists in hydrated salts, but is not classified based on the number of water molecules like sodium metasilicate. In other words, the sodium orthosilicate used as an activator may be either an anhydrous salt or a hydrated salt.

[0031] Figure 1 shows the reaction formula between sodium orthosilicate and water. As can be seen from this reaction formula, sodium orthosilicate reacts with water to produce sodium metasilicate and sodium hydroxide. Therefore, using sodium orthosilicate as an activator makes it possible to omit the use of highly alkaline solutions, which were previously required to obtain hardened geopolymers.

[0032] Figure 2 shows the reaction formula between anhydrous sodium metasilicate and water. As can be seen from this reaction formula, anhydrous sodium metasilicate reacts with water to produce a sodium silicate dimer (water glass) and sodium hydroxide. Therefore, like sodium orthosilicate, when anhydrous sodium metasilicate is used as an activator, the use of a highly alkaline solution can be omitted.

[0033] When sodium orthosilicate is used as the sodium silicate, the amount of sodium orthosilicate is 2 to 50 parts by weight per 100 parts by weight of the active filler. The lower limit of this amount is preferably 5 parts by weight, more preferably 15 parts by weight. Meanwhile, the upper limit of this amount is preferably 45 parts by weight, more preferably 35 parts by weight.

[0034] When anhydrous sodium metasilicate is used as the sodium silicate, the amount of anhydrous sodium metasilicate is 10 to 30 parts by weight per 100 parts by weight of the active filler. The lower limit of this amount is preferably 15 parts by weight. Meanwhile, the upper limit of this amount is preferably 25 parts by weight.

[0035] The particle size of the sodium orthosilicate and anhydrous sodium metasilicate is not particularly limited, but can be adjusted appropriately depending on the application of the hardened geopolymer and the desired mechanical properties of the hardened geopolymer. For example, the particle size is 1.2 mm or less. For another example, the particle size is 1.2 to 2.5 mm.

[0036] The highly alkaline solutions conventionally required to obtain hardened geopolymers have an extremely high pH of 13 or higher, necessitating careful handling during work. In this regard, the geopolymer composition according to the present invention generates sodium hydroxide derived from sodium orthosilicate or anhydrous sodium metasilicate by reaction with water. This reduces restrictions on handling the geopolymer composition, thereby improving work safety. Furthermore, because sodium orthosilicate or anhydrous sodium metasilicate is in powder form, it can be premixed with an active filler and packaged in bags, which has the added advantage of reducing the occurrence of weighing errors at work sites.

[0037] 1-3. Other additives The geopolymer composition according to the embodiment may contain various additives other than the active fillers and active agents described above. Examples of the various additives include aggregates and set modifiers.

[0038] Aggregates are commonly used to increase the material strength of concrete and mortar. Aggregates are classified into fine aggregates and coarse aggregates based on particle size, natural aggregates and artificial aggregates based on origin, and lightweight aggregates, normal aggregates, and heavy aggregates based on density. There are no particular restrictions on the aggregates used in the geopolymer compositions of the present invention, and they can be selected appropriately depending on the intended use of the hardened geopolymer body and the desired mechanical properties to be imparted to the hardened geopolymer body.

[0039] A preferred aggregate is a fine aggregate, and an example of this fine aggregate is silica sand. Silica sand is a sandy material whose main component is silicon dioxide. Preferred silica sands include JIS-compliant products and mixed silica sands whose particle size is adjusted according to the JIS standard.

[0040] When aggregate is added, the amount of the aggregate is not particularly limited and can be adjusted appropriately depending on the application of the hardened geopolymer body and the desired mechanical properties to be imparted to the hardened geopolymer body. When aggregate is added, the amount of the aggregate is, for example, 10 to 300 parts by weight per 100 parts by weight of BFS. In another example, the amount of the aggregate is 150 to 300 parts by weight per 100 parts by weight of BFS. In yet another example, the amount of the aggregate is 10 to 150 parts by weight per 100 parts by weight of BFS.

[0041] Set modifiers are optionally used to ensure working time. Examples of set modifiers include citric acid, tartaric acid, gluconic acid, and malic acid or their salts, alkali metal carbonates, alkali metal bicarbonates, and boric acid.

[0042] When a setting regulator is added, the amount thereof is 1 to 10 parts by weight per 100 parts by weight of the active filler, with the upper limit of this amount being preferably 8 parts by weight, and more preferably 5 parts by weight.

[0043] The various additives may further include a superplasticizer, a thickener (separation reducing agent), and a rust inhibitor. Superplasticizers are used to improve fluidity and fillability without increasing the amount of water. Examples of superplasticizers include air-entraining agents, air-entraining water reducers, water reducers, high-performance water reducers, and high-performance air-entraining water reducers. Thickeners are used to suppress bleeding, which occurs when the amount of water is large or when the cement or aggregate particle size is coarse. Examples of thickeners include inorganic thickeners such as bentonite, and organic thickeners such as cellulose-based and acrylic-based thickeners. Rust inhibitors are used to inhibit corrosion of steel reinforcement materials used in supports, fore-bearing works, etc. Examples of rust inhibitors include inorganic rust inhibitors such as nitrites, chromates, silicates, and phosphates, and organic rust inhibitors such as organic phosphates, organic acid esters, organic acids, sulfonic acids, amines, alkylphenols, mercaptans, and nitro compounds.

[0044] 2. Hardened geopolymer and its manufacturing method The hardened geopolymer according to the embodiment contains the geopolymer composition according to the embodiment and water as a hardener. Hereinafter, the manufacturing method of the hardened geopolymer according to the embodiment will be described with reference to FIG.

[0045] Fig. 3 is a flowchart showing an example of a method for producing a hardened geopolymer according to an embodiment. The example shown in Fig. 3 includes a kneading step S1, a compression step S2, a curing step S3, and a drying step S4.

[0046] The kneading step S1 is a step of mixing and kneading the geopolymer composition according to the embodiment with water as a curing agent. The amount of water added is adjusted appropriately depending on the application of the hardened geopolymer and the desired mechanical properties to be imparted to the hardened geopolymer. In the kneading step S1, a geopolymer composition to which the various additives described above have been added may be used depending on the application of the hardened geopolymer and the desired mechanical properties to be imparted to the hardened geopolymer.

[0047] The compression step S2 is a step of molding and compressing the kneaded material obtained in the kneading step S1. In the compression step S2, a predetermined pressure (for example, a pressure of 1 MPa or more) is applied to the kneaded material in order to stabilize the shape of the kneaded material and increase its density. Hereinafter, the kneaded material that has undergone the compression step S2 will also be referred to as a "compressed kneaded material."

[0048] The curing step S3 is a step in which the compressed kneaded product is cured to allow the condensation reaction (hardening reaction) to proceed. The curing conditions are 3 hours or more at room temperature. The reason for this is that, as will be understood from the experimental examples described later, the geopolymer composition according to the embodiment can obtain the desired mechanical properties even under such conditions. The curing time is set to "3 hours or more" because a minimum curing time of 3 hours is required to obtain the desired mechanical properties. In other words, the range of the curing time is not particularly limited, and may be 3 to 4 hours, 3 to 6 hours, or 3 to 24 hours. Hereinafter, the compressed kneaded product that has undergone the curing step S3 will also be referred to as the "cured kneaded product."

[0049] The kneaded material after the compression step S2 and before being input into the curing step S3 (i.e., the compressed kneaded material) may be a kneaded material in which the condensation reaction has not progressed sufficiently, but may have the desired mechanical properties. In this case, the compression step S2 and the curing step S3 are carried out in parallel, and therefore the compression step S2 and the curing step S3 are not strictly distinguished.

[0050] The drying step S4 is a step of evaporating the water in the cured mixture. The drying of the cured mixture proceeds naturally, but the drying may be accelerated by adjusting the environmental conditions such as the temperature and humidity around the cured mixture. The cured mixture that has reached a certain moisture content corresponds to the geopolymer hardened body according to the embodiment.

[0051] Incidentally, there are cases where the moisture content of the kneaded material (i.e., the compressed kneaded material) before entering the curing step S3 has reached a certain moisture content. In this case, the compression step S2 and the drying step S4 proceed in parallel, and therefore the compression step S2 and the drying step S4 are not strictly distinguished. Also, there are cases where the moisture content of the kneaded material after the curing step S3 (i.e., the cured kneaded material) has reached a certain moisture content. In this case, the curing step S3 and the drying step S4 proceed in parallel, and therefore the curing step S3 and the drying step S4 are not strictly distinguished.

[0052] 3. Experimental Example Next, the embodiment will be described in detail with reference to experimental examples.

[0053] 3-1. Preparation of samples containing sodium orthosilicate Samples of Examples 1-11 and samples of Comparative Examples 1-8 containing the various components shown in Table 1 in the blending ratios shown in Table 1 were prepared.

[0054] [Table 1]

[0055] 3-2. Preparation of samples containing anhydrous sodium metasilicate Samples of Examples 12-17 and samples of Comparative Examples 9-16 containing the various components shown in Table 2 in the blending ratios shown in Table 2 were prepared.

[0056] [Table 2]

[0057] BFS (ground granulated blast furnace slag) "A" shown in Tables 1 and 2 is a sample with a Blaine specific surface area in the standard range (4160 cm 2 / g), ground granulated blast furnace slag "B" is a sample whose Blaine specific surface area is in the range larger than the standard (8470 cm 2 / g). The Blaine specific surface area is a value measured in accordance with JIS R 5201 (Physical Testing Methods for Cement). Sodium orthosilicate "A" shown in Table 1 is a sample with unadjusted particle size, while sodium orthosilicate "B" is a sample whose particle size has been adjusted to 1.2 mm or less by classification.

[0058] 3-3. Sample evaluation The samples of the examples and comparative examples were kneaded to prepare hardened samples. Then, for each hardened sample, (i) flow, (ii) setting time, and (iii) compressive strength were measured. (i) Flow was measured according to the method described in "12. Flow test" of JIS R 5201. (ii) Setting time was measured according to the method described in "9. Setting test" of JIS R 5201. (iii) Compressive strength was measured according to the method described in "11. Strength test" of JIS R 5201.

[0059] Furthermore, based on the measurement results, each hardened sample was evaluated. (i) Regarding flow, taking into consideration the workability as mortar, samples with a flow value of 140 mm or more after 15 drops were evaluated as "good." (ii) Regarding setting time, taking into consideration the time during which work can be performed (usable life), samples with a setting time of 15 minutes or more were evaluated as "good." (iii) Regarding compressive strength, samples with a compressive strength of 3 N / mm3 at 3 hours were evaluated as "good." 2The above samples were evaluated as "good." The evaluation results are shown in Tables 3 and 4.

[0060] [Table 3]

[0061] As can be seen from the results of "Flow" shown in Table 3, the flow values ​​of the samples of Examples 1-11 were all good. Furthermore, as can be seen from the results of "Setting time," the setting times of the samples of Examples 1-3 and 5-9 were all good. The setting times of the samples of Examples 4 and 10 were less than 15 minutes, but the results of Example 11 confirmed that the setting time was extended by adding citric acid. Furthermore, as can be seen from the results of "Compressive strength," the compressive strength of the samples of Examples 1-11 was 3 N / mm after 3 hours of curing in the atmosphere at 20°C (i.e., at room temperature). 2 The above has been shown.

[0062] On the other hand, the sample of Comparative Example 1 had a good flow value but did not harden within 28 days. This was thought to be due to the sodium orthosilicate content being too low. On the other hand, the samples of Comparative Examples 2 and 3 had an excessively high content of sodium orthosilicate, which resulted in a low flow value and a short setting time, leading to the conclusion that they lack practical utility.

[0063] The samples of Comparative Examples 4-8 correspond to samples prepared according to conventional methods. These samples had good flow value and setting time results (although the setting time of the sample of Comparative Example 7, which contained 100% FA as active filler, was longer than that of the other samples). However, the compressive strength results were not good, and it took 28 days of curing at room temperature and 1 day of curing in 60°C steam (i.e., at high temperature) to achieve the desired compressive strength.

[0064] [Table 4]

[0065] As can be seen from the results of "Flow" shown in Table 4, the flow values ​​of the samples of Examples 12-17 were all good. Also, as can be seen from the results of "Setting time," the setting times of the samples of Examples 12-17 were all good. Furthermore, as can be seen from the results of "Compressive strength," the compressive strength of the samples of Examples 12-17 was 3 N / mm after 3 hours of curing in the air at 20°C (i.e., at room temperature). 2 The above has been shown.

[0066] On the other hand, the sample of Comparative Example 9 had a low flow value and a short setting time, leading to the conclusion that it lacked practical use. The reason for this was thought to be due to the blending ratio of anhydrous sodium metasilicate being too high. In contrast, the sample of Comparative Example 10 showed a good flow value but did not harden within 28 days. The reason for this was thought to be due to the blending ratio of anhydrous sodium metasilicate being too low.

[0067] The samples of Comparative Examples 10-16 correspond to samples prepared according to the conventional method. These samples had good flow value results. However, they required a setting time of more than 6 hours and a day of room temperature curing to achieve the desired compressive strength.

[0068] These experimental results confirmed that, according to the embodiment, a highly practical hardened geopolymer having the desired compressive strength can be obtained in a shorter setting time. It was also confirmed that the setting time can be extended by adding citric acid.

Claims

1. A geopolymer composition comprising an active filler comprising at least ground granulated blast furnace slag and sodium silicate as an activator, The sodium silicate is sodium orthosilicate, The content of the sodium orthosilicate is 15 to 50 parts by weight per 100 parts by weight of the active filler. A geopolymer composition characterized by:

2. 10. The geopolymer composition of claim 1, A geopolymer composition wherein the upper limit of the sodium orthosilicate content is 45 parts by weight.

3. 3. The geopolymer composition of claim 1 or 2, The ground granulated blast furnace slag has a Blaine specific surface area in the range of 3000 to 4000 cm ２ / g standard surface area powder and Blaine specific surface area range of 6000 to 10000 cm ２ / g of high surface area powder.

4. 3. The geopolymer composition of claim 1 or 2, A geopolymer composition wherein the active filler further comprises a pozzolanic material.

5. 3. The geopolymer composition of claim 1 or 2, A geopolymer composition wherein the active filler does not include fly ash.

6. 3. The geopolymer composition of claim 1 or 2, After water as a hardener is mixed, the setting time measured according to the method described in the setting test of JIS R 5201 is 10 minutes or more and 1 hour 52 minutes or less. A geopolymer composition.

7. 3. The geopolymer composition of claim 1 or 2, The geopolymer composition further comprising citric acid as a set modifier.

8. A geopolymer hardened body comprising an active filler containing at least granulated blast furnace slag, sodium silicate as an activator, and water as a hardener, The sodium silicate is sodium orthosilicate, The content of the sodium orthosilicate is 15 to 50 parts by weight per 100 parts by weight of the active filler. A hardened geopolymer body characterized by:

9. A kneading step of adding water to a geopolymer composition containing at least an active filler containing blast furnace slag powder and sodium silicate as an activator, and kneading the composition; a curing step of curing the kneaded product obtained by the kneading step at room temperature for 3 hours or more; Including, The sodium silicate is sodium orthosilicate, The content of the sodium orthosilicate is 15 to 50 parts by weight per 100 parts by weight of the active filler. A method for producing a hardened geopolymer body.

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