WO2023120780A1 - Room-temperature fast-curing geopolymer and preparation method therefor - Google Patents

Abstract

The present invention provides a room-temperature fast-curing geopolymer and a preparation method therefor, wherein the geopolymer has: a higher curing rate than conventional geopolymers; a flexural strength increase of 40% or more compared to conventional geopolymers, with a maximum strength of 27.83 MPa; and a compressive strength increase of 20% or more compared to conventional geopolymers, with a maximum strength of 55 MPa. The geopolymer according to the present invention has excellent heat resistance and thus is suitable for flame-retardant performance and fire spread prevention.

Description

Room-temperature high-speed curing geopolymer and its manufacturing method

The present invention relates to a method for producing a geopolymer capable of high-speed curing at room temperature.

Geopolymer, as one of the cement replacement materials, has begun to come into the limelight as a substitute for the existing Portland cement or used as an additive. Geopolymer is an amorphous aluminosilicate cement-based material that is synthesized through polycondensation of a geopolymer precursor and an alkali activator. It is an inorganic material that can be used.

The structure of geopolymer is created by the chemical reaction of alkali polysilicate and oxidized aluminosilicate constituting the Si-O-Al bond, and it is named as geopolymer because it forms a network similar to a polymer during the curing process. . Geopolymer can be synthesized at room temperature or at a low temperature of 100°C or less, and it is expected to reduce carbon dioxide emissions by about 70% compared to cement because carbon dioxide emissions are extremely low during the manufacturing process. In addition, geopolymers can be produced from industrial by-products such as fly ash, and are characterized by a wide range of physical property changes depending on manufacturing conditions.

In addition, optimization of geopolymer raw materials and alkaline activators is highly dependent on geopolymer precursors (e.g. fly ash, metakaolin, etc.), so it is necessary to optimize synthesis conditions according to starting materials and target properties.

In addition, since the physical properties of geopolymer can be adjusted according to additives and reinforcing materials, it can be applied in various fields of application.

Geopolymer is a ceramic material with high purity, so it has high heat resistance and fire resistance, can be cured at room temperature, and its manufacturing method is simple. If it is a material that can be cured at high speed at room temperature with these characteristics, it can be used for industrial heat-resistant members that require heat resistance or repair and finishing materials for buildings.

A simple method widely known in the cement field to speed up the setting is to use calcium cations. The presence of calcium compounds allows calcium ions to function as charge-balancing cations within the geopolymer binder, forming a network (e.g., tobermorite (Ca ₅ Si ₆ O ₁₆ (OH) ₂ 4H ₂ O), gehlenite (Ca ₂ Al(AlSiO ₇ )) and jennite (Ca ₉ Si ₆ O ₁₈ (OH) ₆ .8H ₂ O)) enable high-speed polymerization. For this purpose, raw materials containing CaO may be used, or additional calcium compounds (eg CaCO ₃ and Ca(OH) ₂ ) may be used. For example, when 0.4 mol Ca(OH) ₂ is added, the setting time can be shortened from 15 hours to less than 1 hour, and when 4 wt% of CaO is included, the curing time is from 20 hours to 4 hours. can be shortened to

While the addition of a calcium compound allows for rapid curing, it generally lowers the mechanical strength. For this reason, other reinforcing additives (eg, fillers) are often used in the mixture for high-speed curing compositions.

For example, nano-silica (SiO ₂ ) increases mechanical strength by forming a contracted microstructure (compact structure by filling pores) and promotes the polymerization process (because of its high surface area to volume ratio). By adding an appropriate amount of SiO ₂ to the mixture, it is possible to obtain good mechanical strength as well as to form a dense structure.

As another example, in the case of fibers, the overall void value is lowered and the cross-linking effect is shown by the dispersed fibers. The flexural strength is increased by a factor of 4 by the chopped carbon fibers in the geopolymer. Interestingly, there is a synergistic effect when SiO ₂ and short carbon fibers are used simultaneously. That is, when SiO ₂ is added to the geopolymer containing 2 vol% of PVA fibers, the flexural modulus increases. With the help of SiO ₂ , a shrinkage effect occurs at the fiber/matrix interface, resulting in a compact microstructure and improved workability. Since fibers and SiO ₂ compensate for the low mechanical strength of geopolymer, a synergistic effect in the properties and workability of geopolymer is expected, which is suitable for high-speed curing conditions.

As mentioned above, additives are commonly used for the development of geopolymers. The properties of cured geopolymers are greatly influenced by the input materials: the molarity of the raw materials, the ratio of alkali activators (i.e., alkali hydroxides to alkali silicates), and the mixing ratio of geopolymer to alkali activators and other constituents. .

Until recently, studies on various chemical compositions have been conducted, but the understanding of compositional effects is limited to a narrow range, and controversial conclusions have been drawn. With the inclusion of various additives, the control of parameters and final properties becomes more complex.

In the present invention, while focusing on manufacturing a fast and strong geopolymer composite, a low calcium content geopolymer is developed, and the effect of fumed silica on mechanical properties and short-term durability is demonstrated to provide a room temperature high-speed curing geopolymer. .

The method for producing a high-speed curing type geopolymer at room temperature according to the present invention

Mixing silica with an alkaline solution;

ultrasonic treatment;

Injecting alkali silicate and short fibers;

ultrasonic treatment;

Injecting a mixed solution of metakaolin (MK) and a calcium compound;

Mixing with a speed mixer;

casting; and

It is preferable to include a step of curing at room temperature.

As another embodiment of the present invention, the room temperature high-speed curing geopolymer according to the present invention is an alkali solution; silica; alkali silicates; short fibers; metakaolin (MK); and a calcium compound, and an alkali (M) component ratio of 0.87≤M ₂ O/Al ₂ O ₃ ≤2.0; 0.3≤M ₂ O/SiO ₂ ≤0.7; 6.5≤H ₂ O/M ₂ O≤9.1; is preferably satisfied.

Further, the geopolymer preferably satisfies 2.8≤SiO ₂ /Al ₂ O ₃ ≤4.0.

It is preferable that the said alkali solution is a KOH solution.

It is preferable that the silica is a single or a mixture of colloidal silica and dry silica.

It is preferable that the alkali silicate is composed of sodium silicate, potassium silicate and lithium silicate alone or as a mixture.

It is preferable that the short fibers are short carbon fibers.

The size of the short fibers is preferably 2 to 6 mm.

It is preferable that the calcium compound is calcium hydroxide (Ca(OH) ₂ ), calcium oxide (CaO) or calcium carbonate (CaCO ₃ ).

The meta-kaolin is preferably kaolin calcined at 700 to 900 ° C. for 1 to 5 hours.

It is preferable that the metakaolin has an average particle size of 3 to 30 μm.

It is preferable to mix for 30 to 90 sec at 1500 to 2500 rpm in the speed mixer.

It is preferable that the KOH is 0.3 to 0.9 wt% compared to metakaolin.

It is preferable that the alkali silicate is 0.25 to 1.2 wt% compared to metakaolin.

Preferably, the alkali silicate/KOH ratio in the entire geopolymer is 0.8 to 1.5.

As another embodiment of the present invention, a heat resistant material or heat resistant finishing material comprising the geopolymer according to the present invention is preferred.

As another embodiment of the present invention, a repair material or a repair finishing material comprising the geopolymer according to the present invention is preferred.

The room temperature high-speed curing geopolymer prepared according to the present invention shortens the curing speed and has a flexural strength of up to 31.8 MPa, 40% higher than that of conventional geopolymers, and a compressive strength of up to 66.2 MPa, 20% higher than conventional geopolymers. can be improved to have.

Figure 1 schematically shows the function of dry silica and calcium cations.

2 schematically illustrates a manufacturing method according to the present invention.

Figure 3 schematically shows the strength contours according to the composition ratio of the geopolymer according to the present invention.

Figure 4 schematically shows the flexural strength according to the individual composition ratio of the geopolymer according to the present invention.

The method for producing a high-speed curing type geopolymer at room temperature according to the present invention

Mixing silica with an alkaline solution;

ultrasonic treatment;

Injecting alkali silicate and short fibers;

ultrasonic treatment;

Injecting a mixed solution of metakaolin (MK) and a calcium compound;

Mixing with a speed mixer;

casting; and

It is preferable to include a step of curing at room temperature.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention may be modified in various forms, and the scope of the present invention is not limited to the embodiments described below.

In describing the present embodiments, the same names and reference numerals are used for the same components, and thus redundant additional descriptions are omitted below. Scale ratios are not applied in the drawings referred to below.

Room-temperature high-speed curing geopolymers have multivariable manufacturing conditions (chemical component molar ratio (SiO ₂ , Al ₂ O ₃ , K ₂ O, Ca(OH) ₂ , H ₂ O), and each raw material (MK, colloidal silica) , Ca(OH) ₂ , KOH, K ₂ SiO ₃ )) has a large effect on the final physical properties, so it is not easy to achieve the desired physical properties.

SiO ₂ and Al ₂ O ₃ form the basic structure of geopolymer, and K ₂ O is a chemical component that causes geopolymer reaction. In the case of Si and K, they are supplied from various raw materials. Three sources of SiO ₂ are metakaolin (MK), alkali silicate, and silica, and two sources of K ₂ O are KOH and K ₂ SiO ₃ .

In addition, Ca forms a calcium silicate crystal phase in a Si source and a basic atmosphere, and the crystal phase acts as a nucleation site of geopolymer and serves as a hardening accelerator that speeds up the curing rate. Such calcium silicate is formed during cement curing and plays a role in expressing the strength of cement. However, when the Ca content is high, the interface area between the crystals made of Ca and the geopolymer increases, and this interface causes a decrease in strength and makes molding impossible due to local hardening.

In the case of using the dry silica and calcium hydroxide, the role of the applied calcium cation and the accompanying dry silica (f-SiO ₂ ) is schematically illustrated in FIG. 1 . When the aggregated calcium compound becomes large, it becomes susceptible to local destruction. Fumed silica with high surface area has a significant effect on constructing the activated CASH gel, and it becomes more rigid as the calcium/silicate ratio decreases. Therefore, a relatively high proportion of silica is required to reduce aggregation of calcium particles. Finally, fumed silica can balance the acceleration of cure rate with the reduction of mechanical strength by adjusting the rate of growth of calcium compounds.

Specifically, the method for producing a room temperature high-speed curing geopolymer according to the present invention,

Mixing silica with an alkaline solution and treating it with ultrasonic waves;

Injecting alkali silicate;

Injecting short fibers and subjecting them to ultrasonic treatment;

Injecting a mixed solution of metakaolin (MK) and a calcium compound;

Mixing with a speed mixer;

casting; and

It is preferable to include a step of curing at room temperature.

The alkali solution is preferably a KOH solution.

The silica is preferably a single or a mixture of colloidal silica and fumed silica, but fumed silica is more preferred. Fumed silica was used to provide sufficient Si.

The presence or absence of fumed silica has a significant effect on mechanical strength. Fumed silica allows the geopolymer to be densified, and its dendrite-like particles enable geopolymerization with the geopolymer binder. In addition, as shown in FIG. 1, the presence of fumed silica has a significant effect on the growth of Ca and hinders its growth. Ca growth inhibition slows the curing process and sustains the geopolymerization reaction between alkali activator and metakaolin for a sufficient time. A uniform and continuous reaction enables the geopolymer to be solidified in close proximity, which results in an increase in mechanical strength. The presence of an optimal alkali activator and fumed silica is one means of controlling the reaction.

The alkali silicate is preferably a single or a mixture of sodium silicate, potassium silicate and lithium silicate, but potassium silicate is more preferable.

In addition, it is preferable that KOH is 0.3 to 0.9 wt% and alkali silicate is 0.25 to 1.2 wt% compared to the metakaolin. KOH and flexural strength have a positive correlation, and alkali silicate and flexural strength have a negative correlation. That is, the flexural strength increases as KOH is increased and alkali silicate is decreased. The reason is that the dry silica serving as a bridge is a particle having a high surface area and porosity, and has hygroscopicity. In addition, dry silica directly affects the water demand and thus improves the viscosity of the slurry. Other additives also have the property of increasing viscosity. Therefore, an excessive amount of alkaline activator and water supply are required for smooth mixing. Otherwise, it becomes sensitive to the alkali concentration and the casting workability decreases. After all, an appropriate amount of moisture is required for high-speed curing. The composition in the highest strength region was W _KOH = 0.60, W _K2SiO3 = 0.45, W _Ca(OH)2 = 0.13, and W _f-SiO2 = 0.03 in weight ratio to metakaolin.

In addition, the ratio of K ₂ SiO ₃ /KOH in the entire geopolymer is preferably 0.8 to 1.5. There are several reasons for the increase in strength, but the low viscosity of KOH and alkali silicate solutions and the high reactivity of metakaolin may be one cause. Another cause is dry silica, in which calcium hydroxide is added to maintain calcium ions in a supersaturated state, which cancels out the charge imbalance, shortens the reaction time, and imparts reactivity so that water acts like a filler.

As a structural additive, the short fibers are preferably short carbon fibers, and the size is 2 to 6 mm, preferably 4 mm.

The meta-kaolin is preferably kaolin calcined at 700 to 900 ° C. for 1 to 5 hours. Metakaolin is used as a basic aluminosilicate in geopolymers. In the present invention, kaolinite was calcined at 800° C. for 4 hours.

The main components of metakaolin are Al ₂ O ₃ (44 wt%), SiO ₂ (53 wt%), and CaO, Fe ₂ O ₃ , MgO and K ₂ O as other components less than 0.5 wt%.

Considering the flexural strength, the metakaolin preferably has an average particle size of 3 to 30 μm.

The calcium compound is preferably calcium hydroxide (Ca(OH) ₂ ), calcium oxide (CaO) or calcium carbonate (CaCO ₃ ), but high-speed curing was achieved using calcium hydroxide (Ca(OH) ₂ ). Calcium hydroxide aids in the dissolution of aluminosilicates and increases the condensation and polymerization reactions to enhance mechanical stability. That is, calcium hydroxide was added for fast curing. However, an excessive amount of calcium hydroxide may promote curing prior to the geopolymer reaction. To compensate for the low density resulting from the addition of calcium hydroxide, dry silica was supplied to induce structural densification, and short carbon fibers were used as a reinforcing material.

KOH and potassium silicate were used in the present invention as an alkali activator for accelerating the polymerization reaction. Since calcium ions are highly reactive with aluminosilicate materials, a potassium-based activator was used, achieving a tighter structure and increased strength.

In the speed mixer, it is preferable to mix for 30 to 90 sec at 1500 to 2500 rpm.

On the other hand, as another embodiment of the present invention, the room temperature high-speed curing geopolymer according to the present invention is an alkaline solution; silica; alkali silicates; short fibers; metakaolin (MK); and a calcium compound, and an alkali (M) component ratio of 0.87≤M ₂ O/Al ₂ O ₃ ≤2.0; 0.3≤M ₂ O/SiO ₂ ≤0.7; 6.5≤H ₂ O/M ₂ O≤9.1; is preferably satisfied.

Further, the geopolymer preferably satisfies 2.8≤SiO ₂ /Al ₂ O ₃ ≤4.0 (see FIG. 4).

Hereinafter, the present invention will be described in more detail through a specific manufacturing method.

<Preparation of Geopolymer>

Components used in the examples of the present invention are disclosed in Table 1 below.

Source	Manufacturer (Prod. No.)	Solid content (%)	BET surface area (m2/g)
Kaolin	Daejeong Hwageum (DJ 5041-1400)	-	-
Ca(OH) 2	Daejeong Hwageum (DJ 2511-4400)	-	-
KOH	Daejeong Hwageum (DJ 6597-4405)	40.1	-
K 2 SiO 3	Daejeong Hwageum (DJ 6617-4405)	42.1	-
Fumed SiO 2	OCI (Konasil K-200)	-	200 ± 25
Carbon fiber chops	HD Fiber (C118-3K)	-	-

A specific method for preparing the geopolymer is as follows (see FIG. 2).

Metakaolin (MK) produced by calcining kaolin at 800 °C for 4 hours was used as the main material of the geopolymer.

The metakaolin and calcium hydroxide were prepared separately.

Dry silica was added to a KOH solution in which KOH was dissolved in distilled water, adjusted to pH> 13 to disperse the dry silica well, and sonicated for 5 minutes (SONICS Vibracell-VCX750, Sonics & Materials, Inc., USA).

Subsequently, potassium silicate was added and well dispersed.

Subsequently, short carbon fibers were added and ultrasonically treated for 15 minutes to uniformly disperse them. If the short carbon fiber is not well dispersed, the mechanical strength is inevitably lowered because the geopolymer is hardly wetted into the fiber.

A completely uniform solution is prepared by adding the separately prepared metakaolin and calcium hydroxide.

The homogeneous solution was mixed for 1 minute at 2000 rpm in a speed mixer (DAC 150.1 FVZ-K, UniNanoTech Co., Ltd, USA) to perform a final mixing process.

Since various additives are incorporated, it is important to supply sufficient water and maintain uniform dispersibility.

Since hardening proceeds with the input of calcium compound, agile work is required.

After casting in the silicone mold, the specimens were cured at room temperature for 1 day.

For evaluation, after de-molding, it was further dried and cured at room temperature for 7 days.

<Characteristic evaluation>

Mechanical strength, that is, flexural strength and compressive strength, was measured with a universal tester (5982, Instron Co., Ltd, USA). For flexural strength, as described above, a silicone mold with dimensions of 3.20 x 12.70 x 125 mm ³ (ASTM D790) was used. The actual sample size has a margin of error of ±0.1 mm due to shrinkage. For compressive strength, cylindrical specimens with a diameter of 25 mm and a height of 25 mm were used (ASTM C39). The experimental results are schematically shown in FIGS. 3 and 4 .

In addition, it was tested according to ISO 1182 for the non-combustion reaction. The mass reduction rate of the non-combustible standard is 30%, but the geopolymer of the present invention satisfies the standard at 27%. The increase in the core temperature of the geopolymer of the present invention was 2.4 ° C, confirming its usability as a heat-resistant finishing material.

Samples prepared as above and their physical properties are shown in Tables 2 to 4 below.

Sample No.	Molar ratio				Weight of input materials (g)						Measured
	SiO 2 / Al 2 O 3	Ca(OH) 2 / Al 2 O 3	K 2 O/ SiO 2	H 2 O/ K2O	MK	Ca	Fumed SiO -2	KOH	K 2 SiO 3	H 2 O	Flexural Strength (MPa)
D 1 - 1	2.8	0.4	0.4	6.6	20	2.5	0	6	12	6.2	5.14
D 1 - 2	2.8	0.4	0.5	6.5	20	2.5	0	6	18	3.8	4.22
D 1 - 3	2.8	0.4	0.7	6.6	20	2.5	0	6	24	1.4	4.13
D 1 - 4	3.1	0.4	0.3	7.5	20	2.5	0	9	12	3.2	9.65
D 1 - 5	3.1	0.4	0.5	7.5	20	2.5	0	9	18	0.0	10.64
D 1 - 6	3.1	0.4	0.6	7.2	20	2.5	0	9	24	0.0	8.53
D 1 - 7	3.5	0.4	0.3	8.4	20	2.5	0	12	12	0.0	9.58
D 1 - 8	3.5	0.4	0.5	7.8	20	2.5	0	12	18	0.0	7.14
D 1 - 9	3.5	0.4	0.6	7.5	20	2.5	0	12	24	0.0	5.13
D 1 - 10	2.8	0.4	0.4	6.6	20	2.5	0.3	6	12	6.2	2.71
D 1 - 11	2.8	0.4	0.5	6.5	20	2.5	0.3	6	18	3.8	1.94
D 1 - 12	2.8	0.4	0.6	6.6	20	2.5	0.3	6	24	1.4	2.53
D 1 - 13	3.2	0.4	0.3	7.5	20	2.5	0.3	9	12	3.2	6.30
D 1 - 14	3.2	0.4	0.5	7.5	20	2.5	0.3	9	18	0.0	10.07
D 1 - 15	3.2	0.4	0.6	7.2	20	2.5	0.3	9	24	0.0	7.71
D 1 - 16	3.5	0.4	0.3	8.4	20	2.5	0.3	12	12	0.0	7.83
D 1 - 17	3.5	0.4	0.4	7.8	20	2.5	0.3	12	18	0.0	6.51
D 1 - 18	3.5	0.4	0.6	7.5	20	2.5	0.3	12	24	0.0	5.98
D 1 - 19	2.9	0.4	0.3	6.6	20	2.5	0.6	6	12	6.2	3.92
D 1 - 20	2.9	0.4	0.5	6.5	20	2.5	0.6	6	18	3.8	4.13
D 1 - 21	2.9	0.4	0.6	6.6	20	2.5	0.6	6	24	1.4	3.56
D 1 - 22	3.2	0.4	0.3	7.5	20	2.5	0.6	9	12	3.2	8.60
D 1 - 23	3.2	0.4	0.5	7.5	20	2.5	0.6	9	18	0.0	8.70
D 1 - 24	3.2	0.4	0.6	7.2	20	2.5	0.6	9	24	0.0	8.10
D 1 - 25	3.6	0.4	0.3	8.4	20	2.5	0.6	12	12	0.0	7.87
D 1 - 26	3.6	0.4	0.4	7.8	20	2.5	0.6	12	18	0.0	14.49
D 1 - 27	3.6	0.4	0.6	7.5	20	2.5	0.6	12	24	0.0	10.48

Sample No.	Molar ratio				Weight of input materials (g)						Measured
	SiO 2 / Al 2 O 3	Ca(OH) 2 / Al 2 O 3	K 2 O/ SiO 2	H 2 O/ K2O	MK	Ca	Fumed SiO -2	KOH	K 2 SiO 3	H 2 O	Flexural strength (MPa)	Curing time (m)
D2 - 1	3.2	0.4	0.3	7.7	20	2.5	0.6	9	9	5.6	9.77	21
D2 - 2	3.6	0.4	0.3	8.5	20	2.5	0.6	9	12	3.8	8.24	40
D2 - 3	4.0	0.4	0.3	9.1	20	2.5	0.6	9	15	2.0	8.63	-
D2 - 4	3.2	0.4	0.3	7.6	20	2.5	0.6	12	9	2.6	13.72	19
D 2 - 5	3.6	0.4	0.3	8.3	20	2.5	0.6	12	12	0.8	12.28	32
D2 - 6	4.0	0.4	0.3	8.8	20	2.5	0.6	12	15	0	12.42	-
D2 - 7	3.2	0.4	0.4	7.7	20	2.5	0.6	15	9	0	14.38	15
D2 - 8	3.6	0.4	0.4	8.1	20	2.5	0.6	15	12	0	11.30	44
D 2 - 9	4.0	0.4	0.4	8.4	20	2.5	0.6	15	15	0	8.53	50

Sample No.	Molar ratio				Weight of input materials (g)						Measured
	SiO 2 / Al 2 O 3	Ca(OH) 2 / Al 2 O 3	K 2 O/ SiO 2	H 2 O/ K2O	MK	Ca	Fumed SiO -2	KOH	K 2 SiO 3	H 2 O	Flexural strength (MPa)	Curing time (m)
D3-1	2.8	0.4	0.4	6.5	20	2.5	0.6	12	5	5.6	14.03	12
D3 - 2	2.8	0.4	0.4	6.5	20	2.5	0.6	15	5	3.8	13.33	24
D 3 - 3	2.8	0.4	0.5	6.6	20	2.5	0.6	18	5	2.0	10.93	60
D3 - 4	3.0	0.4	0.3	7.3	20	2.5	0.6	12	7	2.6	18.76	9
D 3 - 5	3.0	0.4	0.4	7.3	20	2.5	0.6	15	7	0.8	17.67	20
D 3 - 6	3.0	0.4	0.5	7.2	20	2.5	0.6	18	7	0	16.95	45
D 3 - 7	3.2	0.4	0.3	8.0	20	2.5	0.6	12	9	0	27.83	7
D 3 - 8	3.2	0.4	0.4	7.7	20	2.5	0.6	15	9	0	19.85	19
D 3 - 9	3.2	0.4	0.5	7.5	20	2.5	0.6	18	9	0	17.73	43

As shown in FIG. 3, the geopolymer according to the present invention has a flexural strength of 40% or more compared to the conventional geopolymer and a maximum of 31.8 MPa in the highest strength space, and 20% or more compared to the conventional geopolymer, the maximum It showed a compressive strength of 66.2 MPa.

As shown in FIG. 4, the flexural strength according to the composition of the geopolymer according to the present invention is shown in an orange area.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible without departing from the technical spirit of the present invention described in the claims. It will be obvious to those skilled in the art.

The present invention relates to a method for producing a geopolymer capable of high-speed curing at room temperature.

Claims (25)

1. Mixing silica with an alkaline solution;

   ultrasonic treatment;

   Injecting alkali silicate and short fibers;

   ultrasonic treatment;

   Injecting a mixed solution of metakaolin (MK) and a calcium compound;

   Mixing with a speed mixer;

   casting; and

   A method for producing a high-speed curing type geopolymer at room temperature, comprising curing at room temperature.
2. [Claim 4] The method of preparing a high-speed curing type geopolymer at room temperature according to claim 1, wherein the alkali solution is a KOH solution.
3. [Claim 4] The method of preparing a high-speed curing type geopolymer at room temperature according to claim 1, wherein the silica is a single or a mixture of colloidal silica and dry silica.
4. [Claim 4] The method of preparing a high-speed curing type geopolymer at room temperature according to claim 1, wherein the alkali silicate is composed of sodium silicate, potassium silicate and lithium silicate alone or as a mixture.
5. [Claim 4] The method for producing a high-speed curing type geopolymer at room temperature according to claim 1, wherein the short fibers are short carbon fibers.
6. [Claim 4] The method of manufacturing a high-speed curing type geopolymer at room temperature according to claim 1, wherein the short fibers have a size of 2 to 6 mm.
7. The method of claim 1, wherein the calcium compound is calcium hydroxide (Ca(OH) ₂ ), calcium oxide (CaO) or calcium carbonate (CaCO ₃ ).
8. [Claim 4] The method for preparing a high-temperature curing type geopolymer according to claim 1, wherein the meta-kaolin is obtained by calcining kaolin at 700-900 °C for 1-5 hours.
9. [Claim 4] The method of preparing a high-speed curing type geopolymer at room temperature according to claim 1, wherein the metakaolin has an average particle size of 3 to 30 μm.
10. The method of claim 1, wherein the mixing is performed in the speed mixer at 1500 to 2500 rpm for 30 to 90 sec.
11. alkali solution; silica; alkali silicates; short fibers; metakaolin (MK); And as a geopolymer prepared from a calcium compound,

    Alkali (M) component ratio 0.87≤M ₂ O/Al ₂ O ₃ ≤2.0; 0.3≤M ₂ O/SiO ₂ ≤0.7; 6.5≤H ₂ O/M ₂ O≤9.1; room temperature fast curing geopolymer.
12. [Claim 12] The geopolymer according to claim 11, wherein the geopolymer satisfies 2.8≤SiO ₂ /Al ₂ O ₃ ≤4.0.
13. [Claim 12] The room temperature high-speed curing geopolymer according to claim 11, wherein the alkali solution is a KOH solution.
14. [12] The geopolymer according to claim 11, wherein the silica is a single or a mixture of colloidal silica and dry silica.
15. [12] The geopolymer according to claim 11, wherein the alkali silicate is composed of sodium silicate, potassium silicate and lithium silicate alone or as a mixture.
16. [12] The geopolymer according to claim 11, wherein the short fibers are short carbon fibers.
17. [Claim 12] The room temperature high-speed curing geopolymer according to claim 11, characterized in that the size of the short fibers is 2 to 6 mm.
18. [Claim 12] The room temperature fast curing type geopolymer according to claim 11, wherein the calcium compound is calcium hydroxide (Ca(OH) ₂ ), calcium oxide (CaO) or calcium carbonate (CaCO ₃ ).
19. [Claim 12] The room-temperature high-speed curing geopolymer according to claim 11, wherein the meta-kaolin is obtained by calcining kaolin at 700-900 °C for 1-5 hours.
20. [Claim 12] The room temperature high-speed curing geopolymer according to claim 11, wherein the metakaolin has an average particle size of 3 to 30 μm.
21. [Claim 14] The room temperature high-speed curing geopolymer according to claim 13, wherein the KOH is 0.3 to 0.9 wt% relative to metakaolin.
22. [6] The geopolymer according to claim 5, wherein the alkali silicate is 0.25 to 1.2 wt% of metakaolin.
23. [Claim 14] The room temperature high-speed curing geopolymer according to claim 13, wherein the alkali silicate/KOH ratio in the entire geopolymer is 0.8 to 1.5.
24. A heat-resistant material or heat-resistant finishing material comprising the geopolymer according to claim 11.
25. A repair material or a repair finishing material comprising the geopolymer according to claim 11.

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