Method for producing a geopolymer composition, method for producing a cured geopolymer, and kit for preparing a geopolymer composition

Abstract

To provide a geopolymer composition having good fresh properties and excellent initial strength.SOLUTION: A geopolymer composition includes an inorganic filler, and an alkali silicate aqueous solution including at least one member selected from the group consisting of sodium and potassium, a retardant, a water reducing agent, and an antifoaming agent, wherein the inorganic filler contains fly ash and blast furnace slag powder, a ratio of the blast furnace slag powder to the total inorganic filler is 45 to 90 mass%, a blending ratio of the retardant to the total inorganic filler is 0.1 to 1.9 mass%, and a ratio of the water reducing agent to the total inorganic filler is greater than 0.2 mass% and equal to or less than 1.0 mass%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to geopolymer compositions and methods for producing the same, geopolymer cured products and methods for producing the same, and kits for preparing geopolymer compositions. [Background technology]

[0002] Geopolymer compositions that harden like concrete by treating amorphous materials such as coal ash with an alkaline solution are known. Compared to ordinary cement, geopolymer compositions can reduce the amount of CO2 generated during production. Examples of silica sources used in geopolymer compositions include liquids such as water glass and fillers such as silica fume. For example, Patent Document 1 proposes a technique to increase the setting time and ensure the pot life of a geopolymer composition by stirring sodium hydroxide with powdered coal ash and blast furnace slag, and then gradually dissolving silica fume. Patent Document 2 proposes a technique to increase the heat resistance after hardening while making it easier to use in on-site construction such as trowel application by setting the molar ratio of silicon contained in silica fume to the alkali source within a predetermined range. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2014-237561 [Patent Document 2] Japanese Patent Publication No. 2021-66613 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, simply adjusting the ratio of alkali and silica sources or modifying the compounding process makes it difficult to achieve a high level of both fresh properties and initial strength in geopolymer compositions. Therefore, this disclosure provides a geopolymer composition and a method for producing the same that have good fresh properties while also exhibiting excellent initial strength. It also provides a kit for preparing geopolymer compositions that allows for easy preparation of geopolymer compositions. Furthermore, it provides a geopolymer cured product with sufficiently high initial strength and a method for producing the same. [Means for solving the problem]

[0005] This disclosure provides a geopolymer composition comprising, in one aspect, an aqueous alkali silicate solution containing at least one selected from the group consisting of an inorganic filler, sodium, and potassium, a retarder, a water-reducing agent, and an antifoaming agent, wherein the inorganic filler comprises fly ash and blast furnace slag fine powder, the blending ratio of blast furnace slag fine powder to the total inorganic filler is 45 to 90% by mass, the blending ratio of the retarder to the total inorganic filler is 0.1 to 1.9% by mass, and the blending ratio of the water-reducing agent to the total inorganic filler is greater than 0.2% by mass and 1.0% by mass or less.

[0006] The above geopolymer composition contains appropriate amounts of retarders and water-reducing agents, while the blending ratio of blast furnace slag fine powder to the total inorganic filler is within a predetermined range. Such a geopolymer composition has good fresh properties and excellent initial strength.

[0007] The retarder preferably contains at least one selected from the group consisting of sodium gluconate, sodium L-tartrate, sodium citrate dihydrate, sodium dihydrogen phosphate, sucrose, and glucose. This extends the pot life (the time during which construction such as casting, compaction, and molding can be carried out) of the geopolymer composition.

[0008] The water reducing agent preferably contains lignin sulfonate. Thereby, the viscosity of the diopolymer composition is reduced, and the fluidity can be further increased. It is preferable that at least silica fume is dissolved in the aqueous alkali silicate solution. Such an aqueous alkali silicate solution can be prepared smoothly.

[0009] In one aspect, the present disclosure provides a diopolymer cured body obtained by curing any of the above diopolymer compositions. Such a diopolymer cured body has a sufficiently high initial strength.

[0010] In one aspect, the present disclosure has a mixing step of obtaining a diopolymer composition by mixing raw materials including at least one selected from the group consisting of an inorganic filler, silica fume, an alkali source containing at least one of sodium hydroxide and potassium hydroxide, water, a retarder, a water reducing agent, and an antifoaming agent. The inorganic filler includes fly ash and blast furnace slag fine powder. The blending ratio of the blast furnace slag fine powder to the total inorganic filler is 45 to 90% by mass, the blending ratio of the retarder to the total inorganic filler is 0.1 to 1.9% by mass, and the blending ratio of the water reducing agent to the total inorganic filler is greater than 0.2% by mass and 1.0% by mass or less. A method for producing a diopolymer composition is provided.

[0011] The diopolymer composition obtained by the above production method contains an appropriate amount of a retarder and a water reducing agent, and the blending ratio of the blast furnace slag fine powder to the total inorganic filler is within a predetermined range. Therefore, it has good fresh properties and excellent initial strength.

[0012] The above manufacturing method preferably includes a first preparation step of preparing a solid composition containing an inorganic filler, fumed silica, and a retarder, a second preparation step of preparing a liquid composition containing an alkali source, water, a water reducing agent, and an antifoaming agent, and the above mixing step of blending the solid composition and the liquid composition to obtain a geopolimer composition. With such a manufacturing method, for example, the solid composition and the liquid composition are prepared separately, and the solid composition and the liquid composition are blended and mixed immediately before using the geopolimer composition, so that a geopolimer composition having good fresh properties and excellent initial strength can be obtained. Therefore, the above manufacturing method is easy to implement on site and is excellent in workability and constructability.

[0013] In one aspect, the present disclosure provides a method for manufacturing a cured geopolimer body, which has a curing step of curing the geopolimer composition obtained by any of the above manufacturing methods. The cured geopolimer body obtained by this manufacturing method has a sufficiently high initial strength.

[0014] In one aspect, the present disclosure provides a kit for preparing a geopolimer composition, which has a first package containing a solid composition and a second package containing a liquid composition. The solid composition contains an inorganic filler, fumed silica, and a retarder. The liquid composition contains an alkali source, water, a water reducing agent, and an antifoaming agent. The alkali source contains at least one selected from the group consisting of sodium hydroxide and potassium hydroxide. The inorganic filler contains fly ash and blast furnace slag fine powder. The ratio of the blast furnace slag fine powder to the whole inorganic filler is 45 to 90% by mass. The ratio of the retarder to the whole inorganic filler is 0.1 to 1.9% by mass.

[0015] In the above kit for preparing a geopolimer composition, the solid composition and the liquid composition are contained in separate packages. Therefore, the solid composition and the liquid composition can be mixed immediately before using the geopolimer composition to easily prepare the geopolimer composition. Such a kit for preparing a geopolimer composition is easy to handle and is excellent in workability and constructability on site.

[0016] The above-mentioned kit for preparing the geopolymer composition may contain a solid composition and a liquid composition in a ratio such that the ratio of the water-reducing agent to the total inorganic filler is greater than 0.2% by mass and less than or equal to 1.0% by mass. This makes it possible to easily prepare a geopolymer composition that has good fresh properties and excellent initial strength. [Effects of the Invention]

[0017] We can provide a geopolymer composition that has good fresh properties and excellent initial strength, as well as a method for producing the same. We can provide a kit for preparing a geopolymer composition that allows for easy preparation of the geopolymer composition. We can provide a geopolymer cured body with sufficiently high initial strength, as well as a method for producing the same. [Modes for carrying out the invention]

[0018] The embodiments of this disclosure will be described below, with reference to the drawings as appropriate. However, the embodiments described below are illustrative examples for illustrating this disclosure and are not intended to limit this disclosure to the following. In the description, the same reference numerals will be used for elements that are the same or have the same function, and redundant explanations will be omitted as appropriate. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. In addition, the dimensional ratios of each element are not limited to the ratios shown. The symbol "~" used in numerical ranges indicates a numerical range that includes the upper and lower limits. For example, "X~Y" indicates a numerical range of "X or less and Y or less".

[0019] A geopolymer composition according to one embodiment comprises an inorganic filler (F), an aqueous alkali silicate solution containing at least one selected from sodium and potassium, a retarder (Ad1), a water-reducing agent (Ad2), and an antifoaming agent (Ad3). Examples of inorganic fillers (F) include amorphous fillers containing Si, Al, and Ca, such as fly ash (FA), blast furnace slag powder (BS), metakaolin, sewage sludge, and volcanic ash. It is preferable that the inorganic filler contains both fly ash and blast furnace slag powder. The blending ratio of blast furnace slag powder (BS) to the total inorganic filler (F) when preparing the geopolymer composition is 45 to 90% by mass. From the viewpoint of sufficiently increasing the initial strength of the geopolymer composition and the cured geopolymer, this blending ratio is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. On the other hand, if the proportion of blast furnace slag fine powder is too high, the pot life tends to be shortened, so this proportion is preferably 85% by mass or less.

[0020] Of the types I to IV specified in JIS A6201:2008, type II fly ash (FA) is preferred. Type II fly ash has superior strength development due to its higher reactivity compared to types III and IV. Although type I fly ash has a larger specific surface area than type II and is therefore more reactive, it tends to be more viscous, and is difficult to obtain due to its high price and limited availability. The specific surface area of ​​the blast furnace slag powder (BS) is preferably 3500 to 6000 cm². 2 / g, more preferably 4000~5000cm 2 The value is / g. While a higher Blaine specific surface area of ​​blast furnace slag fine powder results in higher reactivity and superior strength development, it tends to have higher viscosity and a shorter pot life.

[0021] The amount of inorganic filler (F) added is 1 m of the geopolymer composition. 3 For example, 350-750 kg / m 3 It is fine to have a value of 400-700 kg / m 3 It is fine to have a value of 450-650 kg / m 3It may be. The blending amount of fly ash (FA) is 1 m of the geopolimer composition 3 For example, it may be 80 to 300 kg / m 3 It may be, 100 to 250 kg / m 3 It may be, 100 to 200 kg / m 3 It may be. The blending amount of blast furnace slag fine powder (BS) is 1 m of the geopolimer composition 3 For example, it may be 250 to 650 kg / m 3 It may be, 300 to 600 kg / m 3 It may be, 350 to 550 kg / m 3 It may be.

[0022] The alkaline silicate aqueous solution can be obtained by dissolving silica fume (SF) or the like in an aqueous solution of an alkali source containing at least one selected from the group consisting of sodium hydroxide (NaOH) and potassium hydroxide (KOH). Components of raw materials other than silica fume (SF) may be dissolved in the alkaline silicate aqueous solution. The alkaline silicate aqueous solution may be an aqueous solution obtained by dissolving sodium silicate (Na2SiO3, Na4SiO4, Na2Si2O5, Na2Si4O9, etc.), potassium silicate (K2SiO3, etc.), or both of these, and may be water glass.

[0023] Ordinary silica fume (SF) used in cement compositions can be used. The BET specific surface area of silica fume (SF) may be 10 m 2 / g or more, may be 14 m 2 / g or more, may be 16 m 2 / g or more. Since silica fume with a large BET specific surface area has high reactivity, it can dissolve early in the alkaline aqueous solution and supply SiO2 smoothly. The upper limit of the BET specific surface area of silica fume (SF) may be 20 m 2 / g or less from the viewpoint of easy availability. The blending amount of silica fume (SF) is 1 m of the geopolimer composition 3 For example, it may be 10 to 100 kg / m 3 It may be, 20 to 80 kg / m 3It is acceptable for it to be 30-70 kg / m 3 It may also be the case that the total amount of sodium hydroxide and potassium hydroxide blended (in terms of solid content) is as follows: 3 For example, 40-200 kg / m 3 It is fine to have a load of 60-150 kg / m³. 3 It is fine to have a density of 70-130 kg / m³. 3 Alternatively, an aqueous solution containing such an amount may be used.

[0024] The unit water content in the geopolymer composition is preferably 170 to 238 kg / m³. 3 More preferably 180-220 kg / m³ 3 The unit water content is more preferably 190 to 215. By setting the unit water content within this range, excellent fluidity and high initial strength can be achieved at a sufficiently high level. The water in the geopolymer composition may be included as an aqueous solution of alkali silicate.

[0025] The volume ratio (L / F) of the total amount of silica fume (SF), alkali source, and water added to the inorganic filler (F) is preferably 0.9 to 1.3. This range allows for a sufficiently high level of both excellent fluidity and high initial strength.

[0026] The geopolymer composition may contain fine aggregate (S). Examples of fine aggregate (S) include natural aggregates such as river sand, mountain sand, land sand, and sea sand; artificial aggregates such as crushed sand, silica sand, blast furnace slag fine aggregate, ferronickel slag fine aggregate, and electric furnace oxidized slag fine aggregate; and recycled fine aggregate. These fine aggregates can be used individually or in combination. The surface-dry density of the fine aggregate (S) is 2.2 to 2.9 g / cm³. 3 It is acceptable to have a concentration of 2.4-2.8 g / cm³. 3 That's fine.

[0027] The retarder (Ad1) may include at least one selected from the group consisting of sodium gluconate, sodium L-tartrate, sodium citrate dihydrate, sodium dihydrogen phosphate, sucrose, and glucose. Of these, sodium gluconate is preferred. This allows for a further extension of the pot life.

[0028] The blending ratio of the retarder (Ad1) to the total inorganic filler (F) (Ad1 / F × 100) is 0.1 to 1.9% by mass. Such a geopolymer composition has good fresh properties while also exhibiting excellent initial strength. From the viewpoint of achieving an even higher level of balance between fresh properties and initial strength, the blending ratio (Ad1 / F × 100) is preferably 0.4 to 1.5% by mass, and more preferably 0.7 to 1.3% by mass.

[0029] The water-reducing agent (Ad2) may contain lignin sulfonate and its derivatives as its main components, and examples include naphthalene sulfonic acid-based, aminosulfonic acid-based, or polycarboxylic acid-based agents. The water-reducing agent (Ad2) may contain at least one selected from the group consisting of water-reducing agents, AE water-reducing agents, high-performance water-reducing agents, and high-performance AE water-reducing agents.

[0030] The blending ratio of the water-reducing agent (Ad2) to the total inorganic filler (F) (Ad2 / F × 100) is greater than 0.2% by mass and 1.0% by mass or less. Such a geopolymer composition has good fresh properties while also exhibiting excellent initial strength. From the viewpoint of achieving an even higher level of balance between fresh properties and initial strength, the blending ratio (Ad2 / F × 100) is preferably 0.25 to 0.8% by mass, and more preferably 0.3 to 0.6% by mass.

[0031] As the defoaming agent (Ad3), those incorporated into cement compositions can be used, such as nonionic surfactant types, oil types, and emulsion types.

[0032] The ratio of the defoaming agent (Ad3) to the total inorganic filler (F) (Ad3 / F × 100) is preferably 0.006 to 0.02% by mass, more preferably 0.008 to 0.018% by mass, and even more preferably 0.01 to 0.015% by mass. Geopolymer compositions tend to generate bubbles and have reduced compressive strength when they contain a water-reducing agent (Ad2). Therefore, by including the defoaming agent (Ad3) in the above ratio, it is possible to sufficiently increase the strength development of the geopolymer composition while maintaining the manufacturing cost.

[0033] The geopolymer composition may contain components other than those described above. Examples of such components include calcium carbonate powder, expanding agents, shrinkage reducing agents, rust inhibitors, and waterproofing agents.

[0034] The 15-strand mortar flow of the geopolymer composition is preferably 160-220 mm, more preferably 170-200 mm. Such a geopolymer composition has excellent fluidity and workability. The 15-strand mortar flow is measured by the method described in the examples. The pot life of the geopolymer composition is preferably 120 minutes or more. Such a geopolymer composition has excellent freshness and workability. The pot life is measured by the method described in the examples.

[0035] The flow velocity of the geopolymer composition is preferably 0.5 cm / s or more, more preferably 1.0 cm / s or more, and even more preferably 1.3 cm / s or more. Such a geopolymer composition has high fluidity and therefore excellent workability. The flow velocity is measured by the method described in the examples.

[0036] The geopolymer composition exhibits excellent strength development and has sufficiently high initial strength even under curing conditions of sealed curing at 20°C. In sealed curing at 20°C, the compressive strength of the geopolymer composition at 1 day of age is preferably 4 N / mm². 2 The above is more preferable to 5 N / mm 2That concludes the report. In sealed curing at 20°C, the compressive strength of the geopolymer composition at 7 days of age is preferably 35 N / mm². 2 The above is preferable to 40 N / mm 2 The above is preferable to 45 N / mm 2 That concludes the report. In steam curing at a maximum temperature of 60°C for 3 hours, the compressive strength of the geopolymer composition at 1 day of age is preferably 50 N / mm². 2 The above is more more than 60 N / mm 2 That concludes the explanation. Each compressive strength was measured under the conditions described in the examples.

[0037] A geopolymer cured body according to one embodiment can be obtained by curing the above-described geopolymer composition. This geopolymer cured body has sufficiently high compressive strength.

[0038] A method for producing a geopolymer composition according to one embodiment includes a mixing step of mixing raw materials, which include an alkali source containing at least one selected from the group consisting of inorganic filler (F), silica fume (SF), sodium hydroxide, and potassium hydroxide, water (W), a retarder (Ad1), a water-reducing agent (Ad2), and an antifoaming agent (Ad3), to obtain a geopolymer composition. At least a portion of the water and the alkali source may be blended as an alkaline aqueous solution such as an aqueous NaOH solution and an aqueous KOH solution.

[0039] The molar ratio (A / W) of the total amount of sodium hydroxide and potassium hydroxide to water (W) is preferably 0.1 to 0.7, more preferably 0.1 to 0.5, and even more preferably 0.15 to 0.3. Within this range, not only fresh properties and strength development but also safety can be further enhanced. Water may be added alone when preparing the geopolymer composition, or it may be added as an aqueous solution of NaOH and KOH. The amount of water (W) mentioned above is determined by the sum of these.

[0040] The alkali source and silica fume (SF) are blended such that the molar ratio (Si / A) of SiO2 contained in the silica fume (SF) to the total amount of sodium hydroxide and potassium hydroxide is preferably 0.1 to 0.7, more preferably 0.15 to 0.6, and even more preferably 0.2 to 0.5. Blending within this range allows the SiO2 contained in the silica fume (SF) to dissolve smoothly, resulting in the stable formation of an alkali silicate aqueous solution. Therefore, the initial strength and freshness can be further improved.

[0041] The amounts and ratios of the other components are as described in the embodiment of the geopolymer composition. When each component is mixed, silica fume (SF), etc., dissolves in the alkaline aqueous solution. Inorganic filler (F) and SiO2 contained in the other raw materials may also dissolve in the alkaline aqueous solution, and components other than SiO2 may also dissolve in the alkaline aqueous solution. In this way, an alkaline silicate aqueous solution containing at least one selected from the group consisting of sodium and potassium is produced.

[0042] The above manufacturing method may include a first preparation step of preparing a solid composition containing an inorganic filler (F), silica fume (SF), fine aggregate (S), and a retarder (Ad1) before the mixing step, and a second preparation step of preparing a liquid composition containing an alkali source (containing at least one selected from the group consisting of sodium hydroxide and potassium hydroxide), water, a water-reducing agent (Ad2), and an antifoaming agent (Ad3). In this case, the solid composition and the liquid composition are blended in the mixing step. This allows the raw materials to be mixed to obtain a geopolymer composition.

[0043] In the first preparation step, the prepared solid composition may be packaged to obtain a first package containing the solid composition. In the second preparation step, the prepared liquid composition may be packaged to obtain a second package containing the liquid composition. This allows for the creation of a geopolymer composition preparation kit comprising a first package containing the solid composition and a second package containing the liquid composition. Since the first and second packages are solid and liquid, respectively, separating them allows for smoother transportation. Because the dissolution and curing reactions of silica fume and the like do not proceed until the mixing step is performed, the kit can be stored stably for a long period of time. Therefore, the geopolymer composition preparation kit comprising a first package containing the solid composition and a second package containing the liquid composition offers excellent handling advantages.

[0044] In the solid composition prepared in the first preparation step, the ratio of blast furnace slag fine powder (BS) to the total inorganic filler (F) is 45 to 90% by mass. From the viewpoint of sufficiently increasing the initial strength of the geopolymer composition and geopolymer cured product obtained in the mixing step, this ratio is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. On the other hand, from the viewpoint of suppressing a shortening of the pot life, this blending ratio is preferably 85% by mass or less.

[0045] In the solid composition, the ratio of the retarder (Ad1) to the total inorganic filler (F) (Ad1 / F × 100) is 0.1 to 1.9% by mass. Geopolymer compositions obtained using such solid compositions have good fresh properties while also exhibiting excellent initial strength. From the viewpoint of achieving an even higher level of balance between fresh properties and initial strength, the ratio (Ad1 / F × 100) is preferably 0.4 to 1.5% by mass, and more preferably 0.7 to 1.3% by mass.

[0046] In the mixing step, the solid composition and the liquid composition are blended and mixed. At this time, it is preferable to blend the solid composition and the liquid composition in such a ratio that the ratio of the water-reducing agent (Ad2) contained in the liquid composition to the total amount of inorganic filler (F) contained in the solid composition is greater than 0.2% by mass and 1.0% by mass or less. Furthermore, it is preferable to mix the solid composition and the liquid composition so that the blending amounts and ratios of each component contained in the solid composition and each component contained in the liquid composition are as described in the description of the geopolymer composition.

[0047] There are no particular restrictions on the stirring equipment used in the first preparation step, the second preparation step, and the mixing step. In the second preparation step, since a liquid composition is prepared, a normal container may be used for preparation. In the first preparation step and the mixing step, for example, a mortar mixer, a twin-screw forced mixer, a pan mixer, a grout mixer, or a hand mixer can be used. In this way, a geopolymer composition having good fresh properties and excellent initial strength can be produced. The preferred properties of the geopolymer composition are as described above.

[0048] A method for producing a cured geopolymer according to one embodiment includes a curing step of curing the above-described geopolymer composition. The cured geopolymer obtained in this way has a sufficiently high initial strength.

[0049] Applications of geopolymer cured bodies include on-site construction and, for example, secondary products. When curing a geopolymer composition to produce a geopolymer cured body, curing methods such as sealing and steam curing may be used. Of these, steam curing is preferred because it can improve strength.

[0050] Although embodiments of the present disclosure have been described above, the present invention is not limited in any way to the embodiments described above. [Examples]

[0051] The contents of this disclosure will be described in more detail with reference to examples and comparative examples, but this disclosure is not limited to the following examples.

[0052] (Comparative Examples 1-12, Examples 1-3) [Preparation of Geopolymer Compositions] The materials shown in Table 1 below were used as raw materials for the geopolymer composition. The chemical compositions of silica fume (SF), fly ash type II (FA), and blast furnace slag powder (BS) are shown in Table 2.

[0053] [Table 1]

[0054] [Table 2]

[0055] Geopolymer compositions were prepared using the materials shown in Table 1. Specifically, liquid and solid compositions were prepared separately, and then mixed using a mortar mixer to prepare the geopolymer composition. The liquid composition was prepared by blending aqueous caustic soda solution (SH), water (W), a water-reducing agent (Ad2), and an antifoaming agent (Ad3). The solid composition was prepared by adding silica fume (SF), fly ash type II (FA), blast furnace slag fine powder (BS), sea sand (S1), crushed sand (S2), and a retarder (Ad1) to a mortar mixer and dry-mixing for 30 seconds. Then, the above-mentioned liquid composition was added to the mortar mixer and mixed for 90 seconds. After mixing and scraping, it was mixed again for 90 seconds. In this way, the geopolymer compositions for each example and each comparative example were prepared.

[0056] 1 m of geopolymer composition prepared in each example and each comparative example. 3The unit amounts of each material per serving were as shown in Table 3. As shown in Table 3, some materials were omitted in each comparative example and each example. In addition, in Comparative Examples 1 to 3, an aqueous sodium silicate solution (SS) was added to the liquid composition. Of the water-reducing agents (Ad2), "AE water-reducing agent" from Table 1 was used in Comparative Examples 7 to 9 and Examples 1 to 3, "High-performance water-reducing agent (1)" from Table 1 was used in Comparative Example 10, "High-performance water-reducing agent (2)" from Table 1 was used in Comparative Example 11, and "High-performance AE water-reducing agent" from Table 1 was used in Comparative Example 12.

[0057] [Table 3]

[0058] In Table 3, the symbol "L" represents the total of sodium silicate aqueous solution (SS), caustic soda aqueous solution (SH), water (W), and silica fume (SF); the symbol "F" represents the total of fly ash type II (FA) and blast furnace slag fine powder (BS) (total inorganic fillers); the symbol "S" represents the total of sea sand (S1) and crushed sand (S2) (fine aggregate); and the symbol "Ad" represents the total of retarder (Ad1), water-reducing agent (Ad2), and defoamer (Ad3). Table 4 shows the ratio or proportion of each component and material contained in the geopolymer composition using these symbols.

[0059] In Table 4, "A / W" indicates the molar ratio of sodium hydroxide (NaOH) to water contained in L, and "Si / A" indicates the molar ratio of silicon dioxide (SiO2) to sodium hydroxide (NaOH) contained in L. In Table 4, "Unit water volume" is the total unit volume of water contained in the sodium silicate aqueous solution (SS) and the caustic soda aqueous solution (SH), plus water (W).

[0060] [Table 4]

[0061] [Evaluation of Geopolymer Compositions] The fresh properties (fluidity, pot life, and flow rate) and initial strength (compressive strength) of the geopolymer compositions obtained in each comparative example and example were evaluated using the following procedure.

[0062] <Assessment of liquidity> As a fluidity test, the mortar flow of 15 smears was measured. The mortar flow test was conducted in accordance with JIS R 5201:2015 "Physical Testing Methods for Cement". The measurement results are shown in the "15 smears" column of Table 5.

[0063] <Evaluation of usable time> The pot life was evaluated using a hardness tester (total length: 23 cm, penetration area: conical). A cylindrical container with a diameter of 18.5 cm and a height of 10 cm was placed in the geopolymer composition, and the hardness tester was inserted every 5 minutes to measure the penetration resistance. A penetration resistance of 1.0 N / mm² was selected for the impregnable and moldable material. 2 The usable time was defined as the time not exceeding this value. The measurement results are shown in Table 5.

[0064] <Evaluation of flow velocity> The flow velocity was measured in accordance with the Japan Society of Civil Engineers standard JSCE-F 511-2018, "Draft Method for Flow Test of High-Flow Concrete Using a Funnel." A mortar V-funnel device (top surface 270 mm x 30 mm, discharge port 30 mm x 30 mm) was used for the measurement. After filling the funnel to the top with the geopolymer composition, the discharge port at the bottom was opened and the time required for the sample to flow out (flow time) was measured. The flow time was defined as the time from the opening of the discharge port until the space below the discharge port became visible when observed from the top of the funnel. The average flow velocity was calculated by dividing the volume of the geopolymer composition to be flowed by the cross-sectional area of ​​the discharge port and the flow time. The calculation results are shown in Table 5.

[0065] <Evaluation of initial strength (1)> The geopolymer composition was poured into a predetermined mold and sealed and cured in a constant temperature and humidity chamber at 20±2°C and 60±5% relative humidity until a predetermined age was reached. The resulting cylindrical test specimens (5 cm in diameter × 10 cm in height) were used to measure their compressive strength at 1 day and 7 days of age. The results are shown in Table 5.

[0066] <Evaluation of initial strength (2)> The geopolymer composition was poured into a predetermined mold and steam-cured at a maximum temperature of 60°C. The steam curing process involved a 3-hour preheating period at 20°C, followed by a heating rate of 13.3°C / hr to 60°C, which was maintained for 3 hours, and then a cooling rate of 13.3°C / hr. In this manner, cylindrical specimens (Φ5cm × height 10cm) were obtained. The compressive strength of these cylindrical specimens was measured at 1 day and 7 days of age. The specimens were demolded at 1 day of age, and thereafter air-cured in a constant temperature and humidity chamber at 20±2°C and 60±5% relative humidity. The results are shown in Table 5.

[0067] [Table 5]

[0068] In Table 5, the "Overall Evaluation" is the result of ranking based on the following criteria. A: Initial strength (1) at 1 day of age is 5 N / mm 2 The above applies when the usable time is 120 minutes or more and the flow velocity is 1.3 cm / s or more. B: Initial strength at 1 day of age (1) is 5 N / mm 2 The above applies when the usable time is 120 minutes or more and the flow velocity is less than 1.3 cm / s. C: Initial strength at 1 day of age (1) is 5 N / mm 2 If less than

[0069] Comparative Examples 1 to 3 are geopolymer compositions prepared using an aqueous sodium silicate solution as the silica source. Comparative Example 1 used only fly ash (FA) as the inorganic filler (F), but did not achieve sufficient initial strength. Comparative Example 2 achieved higher initial strength than Comparative Example 1 by substituting a portion of the fly ash (FA) with blast furnace slag powder (BS), but the pot life was considerably shorter and good fresh properties could not be obtained. In Comparative Example 3, sodium gluconate was added as a retarder (Ad1) to Comparative Example 3, but the pot life could not be sufficiently extended and good fresh properties could not be obtained.

[0070] Comparative Examples 4-12 and Examples 1-3 are geopolymer compositions produced by using silica fume as a silica source and dissolving it in an aqueous solution of caustic soda. In Comparative Example 4, a sufficiently long pot life was obtained, but the initial strength (1) did not develop at 1 day of age (uncured). In Comparative Example 5, fluidity was improved by increasing the L / F ratio compared to Comparative Example 4, but similar to Comparative Example 4, the initial strength (1) did not develop at 1 day of age. In Comparative Example 6, the amount of retarder (Ad1, sodium gluconate) was reduced compared to Comparative Example 5, but similar to Comparative Examples 4 and 5, the initial strength (1) did not develop at 1 day of age. On the other hand, in Comparative Example 7, when the retarder (Ad1) was omitted and an AE water-reducing agent (Ad2) and an antifoaming agent (Ad3) were added, a sufficient pot life was not obtained, the viscosity became high, and the flow velocity could not be measured.

[0071] In Comparative Examples 8 and 9, when the retarder (Ad1) was used in relatively small amounts, and an AE water-reducing agent (Ad2) and an antifoaming agent (Ad3) were added, the viscosity was lower than in Comparative Example 7, ensuring a longer pot life and increasing the flow velocity. However, the initial strength (1) did not develop at 1 day of age.

[0072] In Examples 1-3, the amounts of retarder (Ad1, sodium gluconate), AE water-reducing agent (Ad2), and defoaming agent (Ad3) were kept the same as in Comparative Example 9, while increasing the BS / F ratio compared to Comparative Example 9. As a result, sufficient pot life and flow velocity were ensured while significantly increasing the initial strength (1) and (2). The overall evaluation of Examples 1-3 was A or B.

[0073] The material mixing ratios for Comparative Example 8 and Comparative Examples 10-12 are the same, as shown in Table 3. However, Comparative Example 8 uses an AE water-reducing agent containing lignin sulfonate as the water-reducing agent (Ad2). On the other hand, Comparative Examples 10-12 use a different water-reducing agent (Ad2) than Comparative Example 8. Specifically, Comparative Example 10 uses "High-Performance Water-Reducing Agent (1)" from Table 1, Comparative Example 11 uses "High-Performance Water-Reducing Agent (2)" from Table 1, and Comparative Example 12 uses "High-Performance AE Water-Reducing Agent" from Table 1. The water-reducing agents (Ad2) used in Comparative Examples 10-12 do not contain lignin sulfonate. From this, it was found that water-reducing agents (Ad2) containing lignin sulfonate have a high effect in improving fluidity and reducing viscosity. [Industrial applicability]

[0074] This disclosure provides a geopolymer composition having good fresh properties and excellent initial strength, and a method for producing the same. It also provides a geopolymer composition preparation kit that allows for the simple preparation of a geopolymer composition having good fresh properties and excellent initial strength. Furthermore, it provides a geopolymer cured product having sufficiently high initial strength, and a method for producing the same.

Claims

1. A kit for preparing a geopolymer composition, comprising a first package containing a solid composition and a second package containing a liquid composition, The solid composition comprises an inorganic filler, silica fume, and a retarder. The aforementioned delaying agent is sodium gluconate. The liquid composition comprises an alkali source, water, a water-reducing agent containing lignin sulfonate, and an antifoaming agent. The alkali source comprises at least one selected from the group consisting of sodium hydroxide and potassium hydroxide. The inorganic filler comprises fly ash and blast furnace slag fine powder, and the ratio of the blast furnace slag fine powder to the total inorganic filler is 60 to 90% by mass. The ratio of the retarder to the total inorganic filler is 0.4 to 1.5% by mass. A kit for preparing a geopolymer composition, comprising the solid composition and the liquid composition in a ratio such that the ratio of the water-reducing agent to the total inorganic filler is greater than 0.2% by mass and 1.0% by mass or less.

2. The kit for preparing a geopolymer composition according to claim 1, wherein the amount of silica fume blended with 1 m³ of the geopolymer composition, which is a mixture of the solid composition and the liquid composition, is 10 to 100 kg / m³.

3. The kit for preparing a geopolymer composition according to claim 1 or 2, comprising the solid composition and the liquid composition in a ratio such that the molar ratio of SiO₂ contained in the silica fume to the total of the sodium hydroxide and potassium hydroxide is 0.1 to 0.

7.

4. A kit for preparing a geopolymer composition according to any one of claims 1 to 3, comprising the solid composition and the liquid composition in a ratio such that the ratio of the defoaming agent to the total inorganic filler is 0.006 to 0.02% by mass.

5. A first preparation step of preparing a solid composition comprising an inorganic filler, silica fume, and a retarder, wherein the retarder is sodium gluconate, A second preparation step involves preparing a liquid composition comprising an alkali source containing at least one selected from the group consisting of sodium hydroxide and potassium hydroxide, water, a water-reducing agent containing lignin sulfonate, and an antifoaming agent. The process includes a mixing step of blending and mixing the solid composition and the liquid composition to obtain a geopolymer composition. The inorganic filler comprises fly ash and blast furnace slag fine powder, and the blending ratio of the blast furnace slag fine powder to the total inorganic filler is 60 to 90% by mass. The blending ratio of the retarder to the total inorganic filler is 0.4 to 1.5% by mass. A method for producing a geopolymer composition, wherein the blending ratio of the water-reducing agent to the total inorganic filler is greater than 0.2% by mass and 1.0% by mass or less.

6. The method for producing the geopolymer composition according to claim 5, wherein the amount of silica fume blended with 1 m³ of the geopolymer composition is 10 to 100 kg / m³.

7. The method for producing the geopolymer composition according to claim 5 or 6, wherein the molar ratio of SiO2 contained in the silica fume to the total of the sodium hydroxide and potassium hydroxide is 0.1 to 0.

7.

8. A method for producing a geopolymer composition according to any one of claims 5 to 7, wherein the blending ratio of the defoaming agent to the total amount of the inorganic filler is 0.006 to 0.02% by mass.

9. A method for producing a cured geopolymer, comprising a curing step of curing the geopolymer composition obtained by the manufacturing method described in any one of claims 5 to 8.

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