JP5430478B2 - Quick setting agent, spraying material and spraying method using the same - Google Patents

Description

The present invention relates to, for example, a spraying material sprayed onto a ground surface exposed in a tunnel or a slope such as a road, a railway, and a waterway, and a spraying method using the same.

Conventionally, in order to prevent collapse of exposed ground such as tunnel excavation, a rapid setting concrete spraying method in which a quick setting agent is mixed with concrete has been performed (Patent Document 1). This method usually involves preparing sprayed concrete at a cement, aggregate and water metering and mixing plant installed at the excavation site, transporting it with an agitator car, pumping it with a concrete pump, and using a confluence pipe installed in the middle. This is a method of mixing with a rapid setting agent fed from the other side and spraying it to the ground surface as a quick setting sprayed concrete until a predetermined thickness is reached. Accelerating agents include calcium aluminate, a mixture of alkali metal aluminate and alkali carbonate, etc., a mixture of calcium aluminate, alkali metal aluminate, and alkali carbonate, calcium aluminate and 3CaO, etc. A mixture with SiO ₂ is known (Patent Documents 2, 3, 4, 5). These quick setting agents have a function of promoting the setting of cement, and all of them are mixed with cement concrete and sprayed on the ground surface.

In the method of adding the quick setting agent, there is a possibility that the amount of dust is usually increased due to powder mixing by pneumatic transportation. For this reason, the working environment may be deteriorated, and it is necessary to wear protective glasses, a dust mask, or the like when spraying, and a construction method with less dust is required. As a method of generating less dust, a method is proposed in which a quick setting agent is slurried and added to cement concrete, and then an alkali metal aluminate solution is separately pumped, mixed, and sprayed. (Patent Document 6). Since this method uses a highly alkaline liquid, it is difficult to handle, and when spraying, protective glasses or gloves are required, and there is a problem that workability is reduced.

On the other hand, the quick setting construction method which improves a working environment by making a quick setting agent into slurry and mix | blending alums with cement concrete is proposed (patent document 7). In recent years, there has been proposed a quick setting method for improving workability and dust reduction effect and improving quick setting in terms of shortening the work period (Patent Document 8).

However, in recent years, there has been an increase in the spirit of building a recycling-oriented society that reuses waste, and the use of fly ash is the “Act on the Promotion of Effective Use of Resources” (Act No. 48 of 1991, Promotion of effective use of coal ash as a specified by-product). There is also a need for the development of a material with excellent quick setting and initial strength development even in mixed cement mixed with a large amount of fly ash. Furthermore, the demand for quick setting agents has been increasing under the circumstances where spring water and natural ground have deteriorated. The required performance of conventional quick setting agents for cement concrete, such as securing initial setting time and reducing dust Further improvement is required.

As a result of various studies on the problems and requirements, the present inventors have completed the present invention by obtaining knowledge that the problems and requirements can be solved by spraying using a specific quick setting agent. It came.

Japanese Patent Publication No. 60-4149 Japanese Patent Laid-Open No. 64-051351 Japanese Examined Patent Publication No. 56-27457 JP-A-61-026538 JP 63-2105050 A Japanese Patent Laid-Open No. 5-139804 JP-A-5-097491 JP 2003-81664 A

The present invention, calcium aluminates CaO / _Al 2 _{O 3} molar ratio of 2.00 to 2.60, calcium aluminates CaO / _Al 2 _{O 3} molar ratio of 1.50 to 1.95, CaO / Al ₂ O ₃ is a rapid setting agent containing calcium aluminates having a molar ratio of 1.20 to 1.45 and sulfates, and has a specific surface area of 3,000 cm ² / g or more. Calcium aluminates having a CaO / Al ₂ O ₃ molar ratio of 2.00 to 2.60, a Blaine specific surface area of 3,000 cm ² / g or more, and a CaO / Al ₂ O ₃ molar ratio of 1.50 to 1 calcium aluminates are .95, Blaine specific surface area is not less 3,000 cm ² / g or more CaO / _Al 2 _{O 3} molar ratio of calcium aluminates is 1.20 to 1.45, A quick setting agent containing bisulfate, a spraying material containing the quick setting agent and cement concrete, and the spraying material comprising cement concrete containing cement and fly ash The cement concrete is the spray material comprising 100 parts by weight of cement and 50 to 150 parts by weight of fly ash, and the cement is the spray material of ordinary Portland cement, Water is 60 to 90 parts by mass with respect to 100 parts by mass of cement and fly ash, and the quick setting agent contains 15 parts or more with respect to 100 parts of cement and fly ash in total. A spraying method characterized in that the rapid setting agent and cement concrete are mixed and sprayed. A spraying method, wherein the spraying by air conveying the該吹with materials, calcium aluminates CaO / _Al 2 _{O 3} molar ratio of 2.00~2.60, CaO / Al ₂ Calcium aluminates having an O ₃ molar ratio of 1.50 to 1.95 and calcium aluminates having a CaO / Al ₂ O ₃ molar ratio of 1.20 to 1.45 are separately provided with a Blaine specific surface area of 3,000 cm. after pulverizing the above ² / g, calcium aluminates and at Blaine specific surface area of 3,000 cm ² / g or more CaO / _Al 2 _{O 3} molar ratio of 2.00 to 2.60, Blaine specific surface area of 3 , 000cm ² / g or more at and CaO / _Al 2 _{O 3} molar ratio of calcium aluminates is 1.50 to 1.95, Blaine specific surface area of 3,000 cm ² / g or more There calcium aluminates CaO / _Al 2 _{O 3} molar ratio of 1.20 to 1.45, and a method for producing a quick-setting admixture characterized by comprising a mixture of sulfuric acid salts, by the production method A spraying method characterized by merging, mixing and spraying a quick-setting agent produced and cement concrete, wherein the cement concrete contains cement and fly ash, In this spraying method, water in the concrete is 60 to 90 parts by mass with respect to 100 parts by mass in total of cement and fly ash.

By this invention, generation | occurrence | production of the dust which generate | occur | produces by spraying work, such as a tunnel, is suppressed, high quick setting property is acquired, and there exists an effect which eliminates strength expression property fall.

Unless otherwise specified, parts and% in the present invention are shown on a mass basis. Cement concrete is a general term for cement paste, mortar, and concrete.

The calcium aluminates used in the present invention are obtained by mixing a raw material containing calcia, a raw material containing alumina, and the like, followed by heat treatment such as firing in a kiln or melting in an electric furnace. Calcium aluminate is a general term for substances having CaO and Al ₂ O ₃ as main components and having hydration activity. Calcium aluminate is a part of CaO or Al ₂ O ₃ is alkali metal oxide, alkaline earth metal oxide, silicon oxide, titanium oxide, iron oxide, alkali metal halide, alkaline earth metal halide, A compound substituted with an alkali metal sulfate, an alkaline earth metal sulfate, or the like may be used, or a substance in which these are mainly dissolved in CaO and Al ₂ O ₃ may be used. The particle size of the calcium aluminates is in terms of quick-setting property and the initial strength development, Blaine specific surface area (hereinafter, referred to as Blaine) 3,000 cm ² / g or more, more preferably at least 5,000 cm ² / g . If it is less than 3,000 cm < ² > / g, the quick setting property and initial strength expression property of the spray material which mixed the quick setting agent and cement concrete may fall.

Calcium aluminates can be either amorphous or crystalline, and are preferably amorphous. In the present invention, the calcium aluminate is adjusted so that the CaO / Al ₂ O ₃ molar ratio is an ideal amount, mixed and pulverized, melted in an electric furnace, and rapidly cooled.

The CaO / Al ₂ O ₃ molar ratio is measured with fluorescent X-rays. The CaO / Al ₂ O ₃ molar ratio is measured by remelting the rapidly cooled calcium aluminates and adjusting the glass beads (slowly cooled glass).

Calcium aluminates used in the present invention use three types of calcium aluminates A to C in combination. The CaO / Al ₂ O ₃ molar ratio of the calcium aluminates A is 2.00 to 2.60, more preferably 2.15 to 2.45, and most preferably 2.20 to 2.40. The calcium aluminate B has a CaO / Al ₂ O ₃ molar ratio of 1.50 to 1.95, more preferably 1.55 to 1.85, and most preferably 1.60 to 1.80. The CaO / Al ₂ O ₃ molar ratio of the calcium aluminates C is 1.20 to 1.45, more preferably 1.25 to 1.35, and most preferably 1.27 to 1.33.

The calcium aluminates of the present invention are divided into three types of calcium aluminates A to C according to a CaO / Al ₂ O ₃ molar ratio, and the calcium aluminates A to C are individually subjected to a brain value of 3,000 cm ² / g or more. It is preferable to pulverize. Then, it is preferable to mix the pulverized calcium aluminate A, calcium aluminate B, calcium aluminate C, and sulfate. If calcium aluminates are mixed and pulverized without dividing them into three types of calcium aluminates A to C according to the molar ratio, calcium aluminates having a large CaO / Al ₂ O ₃ molar ratio are difficult to pulverize. The quick setting property and initial strength development property of the spray material may decrease.

For example, calcium aluminates having a CaO / Al ₂ O ₃ molar ratio of 2.00 to 2.60 have an effect of improving the initial strength development after spraying. For example, calcium aluminates having a CaO / Al ₂ O ₃ molar ratio of 1.50 to 1.95 have an effect of improving strength development after spraying. For example, calcium aluminates having a CaO / Al ₂ O ₃ molar ratio of 1.20 to 1.45 are effective in improving the long-term strength development of concrete and promoting the pozzolanic reaction of fly ash.

As a preferable mixing ratio (mass ratio) of the calcium aluminates used in the present invention, a calcium aluminate having a CaO / Al ₂ O ₃ molar ratio of 2.00 to 2.60 is A, and CaO / Al ₂ O. Calcium aluminates having a ₃ molar ratio of CaO / Al ₂ O ₃ molar ratio of 1.50 to 1.95 as B and calcium aluminates having a CaO / Al ₂ O ₃ molar ratio of 1.20 to 1.45 When C is C, a mixing ratio of A: B: C = 1: 1.5 to 2.5: 1.5 to 2.5 is preferable, and 1: 1.8 to 2.3: 1.8 to 2 A mixing ratio of .3 is more preferred, and a mixing ratio of 1: 2: 2 is most preferred. When the calcium aluminate A deviates from the mixing ratio, the spraying properties are deteriorated, the reaction to cement or fly ash is inhibited, and the long-term strength may be insufficient. If the calcium aluminate B is out of the mixing ratio, the initial strength properties may be lowered. If the calcium aluminate C deviates from the mixing ratio, the long-term strength properties may decrease.

The sulfates used in the present invention improve the setting properties and strength development properties of the quick setting spray cement concrete. Examples of sulfates include sodium sulfate, potassium sulfate, aluminum sulfate, alum, and gypsum. One or more of these can be used in combination depending on the purpose of use. Among these, gypsum is preferable in that sufficient initial strength development and rapid setting can be obtained and it is suitable for on-site construction. Examples of the gypsum include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum.

The amount of sulfate used is preferably 50 to 150 parts, more preferably 80 to 120 parts, per 100 parts of calcium aluminate. If it is less than 20 parts, the workability and setting properties of quick setting sprayed cement concrete may be reduced, and it may be difficult to promote long-term strength development. If it exceeds 50 parts, initial setting is delayed and initial strength development is reduced. There is a case.

The rapid setting agent used in the present invention can further use an alkali metal aluminate, an alkali metal carbonate, an oxycarboxylic acid, a water retention material, a water reducing agent, and water as necessary.

The amount of the rapid setting agent is preferably 10 parts or more, more preferably 15 parts or more, and most preferably 20 parts or more with respect to a total of 100 parts of cement and fly ash. If it is less than 10 parts, it may be difficult to promote initial setting and strength development of rapid setting sprayed cement concrete. The amount of the rapid setting agent is preferably 30 parts or less, and more preferably 25 parts or less. If it exceeds 30 parts, it may not be preferable in terms of strength properties and cost.

Examples of the cement used in the present invention include ordinary commercially available Portland cement, early strength Portland cement, super early strength Portland cement, moderately hot Portland cement, and various mixed cements obtained by mixing blast furnace slag with these various Portland cements. Is mentioned. These can be used in the form of fine powder. Of these, ordinary Portland cement is preferred.

The fly ash used in the present invention is a powder mainly composed of spherical particles obtained by cooling molten ash when burning pulverized coal in a coal-fired power plant, and these are by-products collected by an electric dust collector or the like. is there. In the fly ash, the quality specified in JIS A 6201 is preferable, and the quality more than the type II equivalent is more preferable in that there is little variation in quality.

The specific gravity of fly ash is preferably 2.0 to 2.5, and more preferably 2.1 to 2.4. The fly ash has a specific surface area (hereinafter referred to as “brain value”) of 3,000 cm ² / g, more preferably 3,500 cm ² / g. The 45 μm sieve residue of fly ash is preferably 40% or less, and more preferably 30% or less. When the fly ash specific gravity, brain value, and 45 μm sieve residue are out of the above ranges, strength development may be insufficient.

The amount of fly ash used is preferably 50 to 150 parts, more preferably 70 to 120 parts, relative to 100 parts of cement. If the amount is less than 50 parts, the amount of dust and the rebound rate may increase, or it may not be preferable in that a large amount of fly ash is not consumed. If the amount exceeds 150 parts, strength development may be insufficient.

The cement concrete used in the present invention contains cement, fly ash and aggregate. Here, the aggregate preferably has a low water absorption rate and a high aggregate strength. The maximum dimension of the aggregate is not particularly limited as long as spraying can be performed. Examples of the fine aggregate include crushed sand, river sand, mountain sand, sea sand, lime sand, and quartz sand. Examples of the coarse aggregate include crushed stone, river gravel, mountain gravel, and lime gravel.

The amount of water used in the present invention is preferably 50 to 95 parts, more preferably 60 to 90 parts with respect to 100 parts in total of cement and fly ash in terms of strength development and workability. If it is less than 60 parts, the workability deteriorates and it is difficult to use a large amount of fly ash, which may be unpreferable, and if it exceeds 90 parts, it may not be preferable in terms of strength development of cement concrete.

In the spraying method using the quick setting agent of the present invention, conventional spraying equipment or the like can be used. For example, a product name “MKW-25SMT” manufactured by Shintech Co., Ltd. can be used for pressure-feeding cement concrete, and a quick-setting agent pressure-feeding device “Natom Cleat” can be used for pressure-carrying quick setting agent.

As a spraying method using the quick setting agent of the present invention, various spraying methods according to required physical properties, economy, workability and the like are possible. As a spraying method using the quick setting agent of the present invention, any of a dry spraying method and a wet spraying method is possible.

As a dry spraying method, for example, dry concrete mixed with cement, fly ash, fine aggregate, and coarse aggregate is conveyed by compressed air, and a Y-shaped pipe is provided in the middle, and a quick setting agent is provided from one side. Examples thereof include a method of spraying a quick setting agent that has been pumped by an adding device and a water that is pumped by a water pump into a dry-type quick setting sprayed cement concrete.

As the wet spraying method, for example, cement, fly ash, fine aggregate, coarse aggregate, and water are added and kneaded, pumped, a Y-tube is provided in the middle, and a rapid setting agent supply device is provided from one side A method of spraying a wet sprayable concrete obtained by merging and mixing the quick-setting agent fed by the above is mentioned.

In the spraying method using the quick setting agent of the present invention, usually, the spraying pressure is preferably 0.2 to 0.5 MPa, and the spraying speed is preferably 4 to 20 m ³ / h.

It is preferable that the pressure of the pumping air for pumping the rapid setting agent is 0.01 to 0.3 MPa higher than the pumping pressure of the cement concrete so that the inside of the pumping pipe is not blocked when the cement concrete is mixed in the pumping pipe of the quick setting agent. .

Experimental example 1
Calcium aluminates were produced from CaO raw material and Al ₂ O ₃ raw material. These calcium aluminates were mixed to prepare calcium aluminates having a mixing ratio shown in Table 1. A binder consisting of 100 parts of cement and 100 parts of fly ash was prepared. A quick setting agent comprising 100 parts of calcium aluminate and 100 parts of gypsum was prepared. A mortar having a sand / binder ratio = 3 and a water / binder ratio = 75% was prepared. 15 parts of a quick setting agent was added to 100 parts of the binder to form a quick setting mortar. The setting time and compressive strength of the quick setting mortar were measured. The results are also shown in Table 1.

<Materials used>
Cement: Ordinary Portland cement, commercial product, Blaine value 3,200 cm ² / g, specific gravity 3.16
Fly ash: JIS II seed product, commercial product, brain value 4,000 cm ² / g, 45 μm sieve residue 22%, specific gravity 2.30
Fine aggregate: Himekawa water system river sand, Itoigawa City, Niigata Prefecture, surface dry state, specific gravity 2.62
CaO raw material: quick lime, CaO content 98%
Al ₂ O ₃ raw material: Bauxite, Al ₂ O ₃ content 84.54%
Calcium aluminate A: CaO / Al ₂ O ₃ molar ratio 2.30, amorphous, Blaine value 6,500 cm ² / g, CaO / Al ₂ O ₃ molar ratio of calcium aluminate is a specific value As described above, CaO raw material and Al ₂ O ₃ raw material were mixed, pulverized, melted in an electric furnace, and rapidly cooled. Calcium aluminates B: CaO / Al ₂ O ₃ molar ratio 1.70, amorphous, brane The CaO raw material and the Al ₂ O ₃ raw material are mixed, pulverized, and melted in an electric furnace so that the value is 6,500 cm ² / g and the CaO / Al ₂ O ₃ molar ratio of calcium aluminates is a specific value. calcium aluminates as quenched C: CaO / _Al 2 _{O 3} molar ratio 1.30, amorphous, Blaine _{^{6,500cm 2 / g, CaO / Al}} 2 O 3 molar calcium aluminates As but it becomes a specific value, a mixture of CaO material and _Al 2 _{O 3} raw material was ground, melted in an electric furnace, quenched those Gypsum: Commercially available anhydrous gypsum crushed ore, Blaine value 5,900cm ² / g

<Measurement method>
Setting time: Measure the quick setting mortar according to the Japan Society of Civil Engineers Standard "Quality Standards for Shotcrete (JSCED-102)" Compressive strength: Measure the quick setting mortar according to JIS R 5201 Brain value: JIS Measured according to R5201 7.1 (specific surface area test) 45 μm sieve residue: Measured according to Annex 1 of JIS A6201

From Table 1, in calcium aluminates, when the mixing ratio A: B: C = 1: 1.5 to 2.5: 1.5 to 2.5, the effect of the present invention cannot be obtained. There is. When the calcium aluminate A having a CaO / Al ₂ O ₃ molar ratio of 2.00 to 2.60 was not contained, the setting time was slow, and spraying was impossible. When the calcium aluminate A having a CaO / Al ₂ O ₃ molar ratio of 2.00 to 2.60 is small, the setting time is improved, but the strength from a material age of 1 hour to a material age of 28 days is reduced. When the calcium aluminate B having a CaO / Al ₂ O ₃ molar ratio of 1.50 to 1.95 was small, the strength expression was delayed until the age of 1 day. When CaO / _Al 2 _{O 3} molar ratio is often calcium aluminates B is 1.50 to 1.95, prolonged strength deteriorated. When the calcium aluminate C having a CaO / Al ₂ O ₃ molar ratio of 1.20 to 1.45 is small, the setting time is shortened, but the compressive strength does not increase even when the material age is 28 days, and the cement And the fly ash reaction could not be promoted. When CaO / _Al 2 _{O 3} molar ratio of calcium aluminates C is often 1.20 to 1.45, the strength to set time or age of 3 hours was reduced.

Experimental example 2
Calcium aluminate A: calcium aluminate B: calcium aluminate C is used in a calcium aluminate ratio of 1: 2: 2 and consists of 100 parts of cement and fly ash in the amount shown in Table 1. The same procedure as in Experimental Example 1 was performed except that the binder was prepared. The water / cement ratio of the mortar without addition of fly ash was 60%. The results are shown in Table 2.

From Table 2, this invention showed favorable intensity | strength expression. Results The amount of fly ash, if 150 parts or less per 100 parts of cement, to satisfy the daily intensity 5N / ^mm 2, 28 days strength 18N / mm ² is generally standard quick-setting property Shotcrete was gotten.

Experimental example 3
Calcium aluminate A: calcium aluminate B: calcium aluminate C is used in a calcium aluminate ratio of 1: 2: 2 and consists of 100 parts of cement and fly ash in the amount shown in Table 1. A binder was prepared. Binder 360 kg / ^{m 3,} fine aggregates 1,075kg / ^{m 3,} the shotcrete was prepared as coarse aggregate 731kg / ^{m 3,} and water 202 kg / ^{m 3,} spray pressure 0.4MPa the shotcrete The mixture was pumped by a concrete pump “MKW-25SMT” under a spraying speed of 10 m ³ / h. On the other hand, 15 parts of quick setting agent were pneumatically fed to 100 parts of the binder using a quick setting agent addition apparatus “NATOM CLEAT” under the condition of a pumping pressure of 0.5 MPa. This quick setting agent was mixed into the shotcrete from one side of the Y-tube to obtain a quick setting shotcrete. Concrete compression strength, rebound rate, and dust amount of this quick setting shot concrete were measured. The results are shown in Table 3.

<Materials used>
Coarse aggregate: Gravel from Himekawa, Itoigawa City, Niigata Prefecture, surface dry condition, specific gravity 2.64, maximum dimension 10mm

<Measurement method>
Concrete compressive strength: The compressive strength at 1 hour of age is that the pin placed in the pullout formwork 25cm wide x 25cm long is covered with the quick setting sprayed concrete from the surface of the pullout formwork, and the pin from the back side of the formwork The pullout strength at that time was determined, and the compressive strength was calculated from the formula of (compressive strength) = (pullout strength) × 4 / (test specimen contact area). The compressive strength after 1 day of age is 20 tons pressure-resistant machine by spraying quick setting sprayed concrete on a form of width 50cm x length 50cm x thickness 20cm, and collecting the specimen 5cm in diameter x 10cm in length. And the compressive strength was determined.
Rebound rate: Quick setting shotcrete was sprayed on a simulated tunnel having a height of 3.5 m and a width of 2.5 m created in an arch shape with an iron plate at a pumping speed of 10 m ³ / h for 10 minutes. After that, (Rebound rate) = (Amount of quick setting sprayed concrete dropped without adhering to the simulated tunnel) / (Amount of quick setting shot concrete sprayed to the simulated tunnel) x 100 (%) did.
Dust amount: Quick setting shot concrete was sprayed to the simulated tunnel at a pumping speed of 10 m ³ / h for 10 minutes. Thereafter, the amount of dust was measured at a fixed position of 3 m from the spraying place.

From the results of Table 3, the present invention reduced the amount of dust and the amount of rebound, and obtained results that satisfied the compressive strength. If fly ash was 50-150 parts, the rebound amount was reduced further and the result which satisfied the compressive strength was obtained.

By using the quick setting agent of the present invention, it is possible to consume a large amount of fly ash, consider effective promotion of resources, and reduce the amount of dust generated. Furthermore, since high strength is obtained at the initial stage of spraying, safety is improved.

By adopting the spraying material of the present invention and the spraying method using it, the workability is improved by suppressing the generation of dust generated by the spraying work such as tunnels, and the spring water and natural ground surface deteriorated. Even under circumstances, high quick setting properties are obtained, and there is an effect of eliminating the decrease in strength.

Claims (14)

Calcium aluminates with a CaO / Al ₂ O ₃ molar ratio of 2.00 to 2.60, calcium aluminates with a CaO / Al ₂ O ₃ molar ratio of 1.50 to 1.95, CaO / Al ₂ A rapid setting agent comprising calcium aluminates having an O ₃ molar ratio of 1.20 to 1.45 and sulfates. Calcium aluminates having a Blaine specific surface area of 3,000 cm ² / g or more and a CaO / Al ₂ O ₃ molar ratio of 2.00 to 2.60, a Blaine specific surface area of 3,000 cm ² / g or more and a CaO Aluminates having an Al / Al ₂ O ₃ molar ratio of 1.50 to 1.95, a Blaine specific surface area of 3,000 cm ² / g or more, and a CaO / Al ₂ O ₃ molar ratio of 1.20 to 1. 45, a quick setting agent comprising calcium aluminates and sulfates. A spray material comprising the quick setting agent according to claim 1 or 2 and cement concrete. The spraying material according to claim 3, wherein the cement concrete contains cement and fly ash. The spray material according to claim 3 or 4, wherein the cement concrete contains 100 parts by mass of cement and 50 to 150 parts by mass of fly ash. The spray material according to claim 3, wherein the cement is ordinary Portland cement. The spray material according to any one of claims 3 to 6, wherein water in the cement concrete is 60 to 90 parts by mass with respect to 100 parts by mass of cement and fly ash in total. The spraying material according to claim 3, wherein the quick setting agent is contained in an amount of 15 parts or more with respect to 100 parts in total of cement and fly ash. A spraying method characterized in that the rapid setting agent according to claim 1 or 2 and cement concrete are mixed and sprayed. A spraying method according to claim 3, wherein the spraying material according to claim 1 is air-conveyed and sprayed. Calcium aluminates with a CaO / Al ₂ O ₃ molar ratio of 2.00 to 2.60, calcium aluminates with a CaO / Al ₂ O ₃ molar ratio of 1.50 to 1.95, CaO / Al ₂ O ₃ after the molar ratio is ground to calcium aluminates separately Blaine specific surface area of 3,000 cm ² / g or more is 1.20 to 1.45, and the Blaine specific surface area of 3,000 cm ² / g or more CaO Aluminates having a / Al ₂ O ₃ molar ratio of 2.00 to 2.60, a Blaine specific surface area of 3,000 cm ² / g or more, and a CaO / Al ₂ O ₃ molar ratio of 1.50 to 1. calcium aluminates are 95, calcium Blaine specific surface area is not less 3,000 cm ² / g or more CaO / _Al 2 _{O 3} molar ratio of 1.20 to 1.45 a Laminate-class, and method for producing a quick-setting admixture characterized by comprising a mixture of sulfates. A spraying method characterized by merging, mixing and spraying a rapid setting agent produced by the production method of claim 11 and cement concrete. The spraying method according to claim 11 or 12, wherein the cement concrete contains cement and fly ash. The spraying method according to claim 11, wherein water in the cement concrete is 60 to 90 parts by mass with respect to 100 parts by mass in total of cement and fly ash.