JP5785427B2 - Spraying material and spraying method using the same - Google Patents

Description

  The present invention mainly relates to a spraying material used in the civil engineering and construction industry and a spraying method using the same.

2. Description of the Related Art Conventionally, in order to prevent collapse of exposed ground such as tunnel excavation, a quick setting mortar in which a quick setting agent is mixed with mortar or concrete or a concrete spraying method has been performed (see Patent Documents 1 and 2).
These methods are usually done by 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, 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. Also, in the TBM method, in order to stabilize the natural ground immediately after excavation, a mortar in which hydraulic components and aggregates are blended in advance at the factory is used, water is mixed and pumped, and the confluence provided in the middle It is a method of mixing as a quick setting spray mortar by mixing with a quick setting agent from the other side with a pipe.

Accelerating agents used include calcium aluminate, a mixture of alkali metal aluminate and alkali metal carbonate, etc., and a mixture of calcium aluminate, alkali metal aluminate, and alkali metal carbonate, A mixture of calcium aluminate and 3CaO.SiO ₂ (tricalcium silicate) is known (see Patent Documents 3 to 6).
These quick setting agents have a function of promoting the setting of cement, and both are mixed with mortar and concrete and sprayed on the ground surface. A quick-setting agent is an admixture necessary for sprayed mortar and concrete in order to suppress loosening of natural ground at an early stage. In recent years, the use of a liquid quick-setting agent mainly composed of aluminum sulfate in consideration of a working environment that generates a small amount of dust and has little alkali irritation to the human body is increasing (Patent Documents 7 to 9). Both are excellent in that the amount of dust generated can be suppressed and the alkali irritancy to the human body is low, but the condensation rate immediately after spraying is slower than that of general quick setting agents, and there is a case where there is spring water, etc. If attached, it may fall off. Also, spraying with a concrete mix with an increased amount of cement tends to solve the setting speed problem, but there is an economic demerit that material costs are significantly increased.

On the other hand, as a method of generating a small amount of dust, there is also known a technique in which a powder rapid setting agent is added to slurryed concrete with water and sprayed (Patent Documents 10 to 13). Although this method can reduce the amount of dust generation and improve the initial setting property, the slurry-like quick-setting agent shows alkalinity and is actually not improved in terms of irritation to the human body due to alkali.
In addition, a slurry obtained by separately pumping and mixing a rapid hardening agent containing calcium aluminate, alkali metal sulfate, gypsum and water-retaining substance and slurry water containing aluminum and sulfur into concrete. A spraying material containing a quick setting agent is known (Patent Document 12). This method is a method in which a quick setting agent containing calcium aluminate is slurried with acidic slurry water containing aluminum and sulfur and added to the concrete, so there is little irritation to the human body and the setting speed is also a general quick setting agent. Is excellent in terms of good initial strength development.
However, a system for air-conveying a powder quick-setting agent containing calcium aluminate and a system for pumping acidic slurry water are required, which complicates the spraying system and increases equipment costs.

In addition, spray materials containing quick setting slurry containing water and powder quick set agent are known to hydraulic concrete (containing calcium aluminate), polymer emulsion, aggregate, cement concrete containing water. (Patent Document 13). This method also requires a system that pneumatically conveys the powder accelerating agent and a system that pumps slurry water, making it a complicated spraying system and increasing equipment costs, and the calcium aluminate used. is the cement concrete side, hydration activity using weak Auin _{(4CaO · 3Al 2 O 3 ·} SO 3), a strong calcium aluminate hydration activity as quick-setting admixture (12CaO · _7Al 2 _{O 3)} It is fundamental to use a powder accelerating agent as a main component, and there is no actual example of applying calcium aluminate that can be hardened by mixing with cement.

As a spraying technique using a specific cement as a spraying material, the content of 3CaO · SiO ₂ is 45 to 75% by weight, the content of 3CaO · Al ₂ O ₃ is 6 to 12% by weight, and alkali sulfate is Na ₂ O. A clinker powder consisting of 0.4 to 0.7% by weight in terms of the balance, the balance being mainly composed of 2Ca0 · SiO ₂ (dicalcium silicate), 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ (tetracalcium iron aluminate), A technology using a cement having a Blaine specific surface area of 3200 to 4700 cm ² / g obtained by blending 2.5 to 4.0% by weight of gypsum containing 30% or more of insoluble anhydrous gypsum in terms of SO ₃ , coal A fired product made from coal ash generated during combustion, comprising 10 to 40% by weight of 3CaO · Al ₂ O ₃ (tricalcium aluminate), and at least 3CaO · Si O ₂ , a spraying method using a hydraulic composition (CA eco-cement) composed of a calcined product and gypsum containing one or more of 2CaO · SiO ₂ (Patent Document 15), using early strength Portland cement, water / Wetted concrete with a cement ratio of 33 to 38% by weight and a slump of 15 cm or more in combination with a quick setting agent (Patent Document 16), as a mineral phase The present invention relates to a cement composition for spraying method comprising as a main component an early-strength cement-based hydraulic composition containing 3CaO · SiO _{2 in an amount} of 50 to 70% by weight and 3CaO · Al ₂ O _{3 in an amount} of 6 to 20% by weight and hydraulic alumina. (Patent Document 17).
Patent Documents 14 to 17 relate to a technique aimed at improving the initial and / or long-term strength development of shotcrete, and Patent Document 17 describes an alkali-free powder rapid setting agent in addition to the improvement of strength development. It also refers to the suppression of alkali-aggregate reaction by combining. In these techniques, 3CaO · Al ₂ O ₃ as a mineral phase of cement contains 6% by weight or more, and there is no example relating to the strength development of fresh concrete or shotcrete with little temperature dependency.

Japanese Patent Publication No. 60-4149 Japanese Patent Laid-Open No. 9-227198 Japanese Patent Laid-Open No. 64-051351 Japanese Examined Patent Publication No. 56-27457 JP-A-61-026538 JP 63-2105050 A Japanese Patent Laying-Open No. 2005-60201 JP 2005-89276 A JP 2008-30999 A JP 05-139804 A JP 05-097491 A JP 2007-277051 A JP 2002-137993 A Japanese Patent Laid-Open No. 11-21158 JP 2001-130939 A JP 2001-302322 A JP 2003-40659 A

  The present invention can produce spray concrete with low slump loss and low temperature dependency even when alumina cement with high hydration activity is contained in the concrete by using a cement with a specific mineral composition. By applying a hardening accelerator composed mainly of aluminum sulfate, spraying mortar or concrete with low dusting, low rebound, low alkali stimulation to the human body and low temperature dependence can be realized. Can be provided. Therefore, it is economically advantageous.

That is, the present invention is (1) a cement containing an insoluble residue having a specific surface area of 2500 cm ² / g or more in a brane , and a mineral composition calculated from the Borg formula is 50-60 mass% tricalcium silicate, calcium 0-4 wt%, and cement 100 parts by a four calcium 10-18 wt% iron aluminate, and aggregate, 0.5 to 10 parts by weight in terms of solid content of the curing accelerator containing aluminum sulfate (2) Spraying material of (1) containing 1 to 20 parts by mass of alumina cement with respect to 100 parts by mass of cement, (3) Alkali metal salt, amine compound, fluorine compound (1) or (2) spray material containing one or more selected from among the above, (4) a curing accelerator containing aluminum sulfate is an alkali metal salt, an amine compound, Any one of (1) to (3), which contains one or more selected from silicon compounds, (5) any of (1) to (4) which contains a setting retarder (6) A spraying material according to any one of (1) to (5) containing a dispersant, (7) A spraying material according to any one of (1) to (6) containing a fiber (8) Cement concrete or mortar is manufactured by mixing spray materials other than hardening accelerator containing aluminum sulfate with water, pumping it, and containing compressed air and aluminum Xnium sulfate in front of the nozzle A spraying method using the spraying material of any one of (1) to (7).

  Even if alumina cement with high hydration activity is included in the concrete, it is possible to produce spray concrete with low slump loss and low temperature dependence, low dusting, low rebound, and low alkali stimulation to the human body. realizable. Further, it is possible to provide a spray material with excellent setting properties, and since it is difficult to inhibit long-term strength development, it is advantageous in terms of performance and economy. In addition, the spraying system does not require a powder transport device, and can be applied with a liquid quick-setting agent pressure pump.

Hereinafter, the present invention will be described in detail.
In the present invention, “parts” and “%” are based on mass unless otherwise specified.

  The cement used in the present invention is a cement having a mineral composition consisting of 50-60% tricalcium silicate, 0-4% tricalcium aluminate, and 10-18% iron calcium aluminate, and other components. These include dicalcium silicate, calcium sulfates, calcium carbonate and the like. Moreover, as a Portland cement prescribed | regulated to JIS, a sulfate-resistant cement can also be used.

The fineness of the cement used in the present invention is not particularly limited as long as it has a Blaine specific surface area of 3000 cm ² / g or more.

The insoluble residue having a brain specific surface area of 2500 cm ² / g according to the present invention is an insoluble residue determined by a test of JIS R 5202 and is not particularly limited as long as it contains a large amount of silica. For example, those derived from fly ash, finely pulverized quartz powder, silica fume and the like can be mentioned. Among these, it is preferable to use fly ash which is easily available and has little fluidity inhibition.
Although the usage-amount of an insoluble residue is not specifically limited, What is necessary is just 5-20 mass parts with respect to 100 parts of cement except an insoluble residue.
The present invention includes an insoluble residue having a Blaine specific surface area of 2500 cm ² / g, tricalcium silicate (3CaO · SiO ₂ ) 50-60%, tricalcium aluminate 0-4%, iron tetracalcium aluminate 10 It has been found that by combining with a cement mineral composition in the range of 18%, it is possible to provide a spray material having characteristics such as low temperature dependence with respect to initial and long-term strength.

As the alumina cement of the present invention, it is possible to use alumina cement No. 1, alumina cement No. 2, fondue, and high alumina cement further improved in purity of aluminum and calcium. Blaine specific surface area is 4000 cm ² / g or more, and it is preferable to use one corresponding to alumina cement No. 1. When mixed with a liquid accelerator containing aluminum sulfate as a main component, it exhibits a rapid setting action.
Alumina cement has a lower hydration activity when added to cement than calcium aluminate and gypsum compositions represented by 12CaO · 7Al ₂ O ₃ and 3CaO · Al ₂ O ₃ compositions. Therefore, it is advantageous for securing working time.
However, it is difficult to secure a working time of 1 hour or more in the addition region that exhibits quick setting performance when sprayed. Therefore, it is possible to secure a sufficient working time by reducing the 3CaO · Al ₂ O ₃ component contained in the cement as much as possible. As other effects, it relates to the strength development of the cured product after adding fresh properties and a quick setting agent. Temperature dependency is reduced. In addition, it has become possible to exert the effect of suppressing the rate of strength reduction with respect to the strength of base mortar and concrete to which no quick setting agent is added.
The amount of the alumina cement used in the present invention is preferably 1 to 20 parts and more preferably 4 to 15 parts with respect to 100 parts of cement. If it is less than 1 part, it is difficult to improve the setting property when the liquid quick-setting agent is added, and if it exceeds 20 parts, it may be difficult to maintain the fluidity of the concrete.

The aggregate used in the present invention is not particularly limited, and any commercially available aggregate can be used, and there is no problem as long as it does not hinder spray construction.
The amount of aggregate used is 50 to 800 parts with respect to 100 parts of cement, and when used with mortar, the sand having an aggregate particle size of 5 mm may be adjusted to 50 to 300 parts with respect to 100 parts of cement. When using in concrete, adjust the sand with an aggregate particle size of 5 mm and gravel with an aggregate particle size of 15 mm to a fine aggregate ratio in the range of 50-75%, Adjustment may be made at ~ 800 parts.

  The aluminum sulfate of the present invention is a component that accelerates the setting of cement or alumina cement, and commercially available products can be used. For example, liquid aluminum sulfate commercially available as a water flocculant, or powdered aluminum sulfate (anhydrous salt or hydrated salt) dissolved or slurried in any concentration can be used.

In this invention, 1 type, or 2 or more types chosen from an alkali metal salt, an amine compound, and a fluorine compound can be used together. These substances may be added to the cement mortar or concrete side, or may be contained on the hardening accelerator side containing aluminum sulfate.
All of these substances are substances that have the effect of further increasing the initial setting rate.

The alkali metal salt used in the present invention is sulfuric acid, nitric acid, carbonic acid, bicarbonate, silicic acid, phosphoric acid, lithium borate, sodium, potassium salt, oxalic acid, malic acid, gluconic acid, citric acid, lactic acid Carboxylic acid such as tartaric acid, formic acid, acetic acid, propionic acid, stearic acid, and lithium salt of oxycarboxylic acid can be used. Among these, use of carbonic acid, a lithium salt of sulfuric acid, or sodium carbonate, which has a high effect of increasing the setting speed, is preferable.
0.5-20 parts are preferable with respect to 100 parts of aluminum sulfate solid content, and, as for the usage-amount of an alkali metal salt, 1-15 parts is more preferable. If the amount is less than 0.5 part, the effect of further increasing the setting speed may not be expected. If the amount exceeds 20 parts, the enhancement effect may reach a peak and the long-term strength development may be reduced.

Examples of the amine compound used in the present invention include trimethylamine, diethylamine, triethylamine, propylamine, allylamine, cyclohexylamine, cyclobutylamine, monoethanolamine, diethanolamine, triethanolamine, hexamethylenediamine, pyridine, and aniline. In addition, a quaternary ammonium salt in which an alkyl group having 1 to 30 carbon atoms (a benzene ring, a carbonyl group, a hydroxyl group, an alkenyl group having an unsaturated bond, or the like) is bonded to the amine pair and ionized can also be used. Examples of a pair of anions include chlorine ions, bromine ions, fluorine ions, iodine ions, nitrate ions, hydroxy ions, acetate ions, sulfate ions, carbonate ions, and bicarbonate ions. Among these, it is preferable to use triethanolamine, quaternary ammonium salt, or the like having good affinity with water or an alkaline substance such as cement.
The amount of the amine compound used is preferably 0.5 to 20 parts, more preferably 1.0 to 15 parts, per 100 parts of aluminum sulfate solid content. If it is less than 0.5 part, the effect of further improving the setting speed may be small, and if it exceeds 20 part, there is a possibility of inhibiting strength development.

The fluorine compound used in the present invention is not particularly limited as long as it is a compound that dissolves or disperses in water. Fluoride, silicofluoride, boron fluoride, organic fluorine, and hydrofluoric acid Fluorine compounds such as these can be used, and one or more of these can be used.
Examples of the fluoride salt include lithium fluoride, sodium fluoride, potassium fluoride, calcium fluoride, aluminum fluoride, and cryolite. Cryolite can be either natural or synthetic.
Examples of the silicofluoride include ammonium silicofluoride, sodium silicofluoride, potassium silicofluoride, and magnesium silicofluoride.
Boron fluoride salts include boron fluoride, boron trifluoride, boron trifluoride monoethylamine complex, boron trifluoride acetic acid complex, and boron trifluoride triethanolamine, ammonium borofluoride, sodium borofluoride, borofluoride Examples thereof include potassium and ferrous borofluoride.
In the present invention, a fluoride salt is preferred from the viewpoints of high safety, low production cost, and excellent coagulation properties.
The amount of the fluorine compound used is preferably 5 to 40 parts, more preferably 10 to 30 parts, per 100 parts of aluminum sulfate solid content. If it is less than 5 parts, the effect of increasing the setting speed may be small, and if it exceeds 40 parts, long-term strength may be inhibited.

The solid content of the curing accelerator containing aluminum sulfate of the present invention is preferably 22 to 40%. If it is less than 22%, it may be difficult to obtain a sufficient coagulation force. If it exceeds 40%, precipitates are generated due to temperature changes, and storage stability may be deteriorated.
The use amount of the curing accelerator of the present invention is preferably 0.5 to 10 parts, more preferably 1 to 7 parts in terms of solid content with respect to 100 parts of cement. If it is less than 0.5 part, it may be difficult to give sufficient setting force. If it exceeds 10 parts, the water-cement ratio will increase too much, and the strong flash immediately after the addition of the hardening accelerator will be inhibited and the long-term strength will decrease. There is a case.

The composition of the cement mortar and concrete of the present invention is not particularly limited as long as spraying is possible. As a general concrete blend, it is often carried out with a slump of about 10 cm, W / C = about 60%, s / a = about 60%, a cement amount of about 360 kg / m ³ , and a maximum gravel dimension of 13 mm. in the high strength type concrete, about slump 20～26Cm, in slump flow 25~70cm, W / C = 30~50% approximately, s / a = 60% approximately, the amount of cement 400~600kg / ^{m 3} approximately, gravel Often implemented with a maximum dimension of 15 mm.
As the mortar, for example, dry mortar of about 100 to 250 parts of sand with respect to 100 parts of hydraulic powder mainly composed of cement, and water is 12 to 25 parts with respect to 100 parts of the total of hydraulic powder and sand. In many cases.
The setting retarder used in the present invention is used for the purpose of controlling the fluidity retention time of concrete or mortar before adding a curing accelerator.

The setting retarder of the present invention includes citric acid, malic acid, gluconic acid, tartaric acid, oxycarboxylic acids such as sodium and potassium salts thereof, saccharides such as sucrose, one or a mixture of two or more thereof, Mixtures of these with alkali metal salts such as carbonic acid, silicic acid and sulfuric acid can be mentioned.
Of these, the use of oxycarboxylic acids alone or a mixture of oxycarboxylic acids and alkali metal carbonates is preferred.
The amount of setting retarder used is preferably 0.02 to 2 parts, more preferably 0.1 to 1 part, per 100 parts of cement. If it is less than 0.02 part, it may be difficult to adjust the fluidity, and if it exceeds 1 part, the initial strength development may be inhibited.

The dispersant used in the present invention is used for the purpose of adjusting the fluidity of mortar and concrete added with water and kneaded.
As a kind of dispersing agent, it does not specifically limit and what is marketed can be used. For example, naphthalene sulfonate-based, lignin sulfonate-based, melamine-based, polycarboxylic acid-based dispersants can be used. Two or more of these may be used in combination. The use of a polycarboxylic acid-based dispersant is preferable in that fluidity can be widely adjusted with low addition.
The amount of the dispersant used is preferably 0.05 to 3 parts and more preferably 0.3 to 2 parts with respect to 100 parts of cement. If it is less than 0.05 part, the effect which can adjust fluidity | liquidity may be small, and when it exceeds 3 parts, there exists a possibility of inhibiting strength expression.

The fiber used in the present invention is used for the purpose of improving the bending properties of the obtained cured product or improving crack resistance.
Examples of the fiber include vinylon fiber, polypropylene fiber, polyethylene fiber, nylon fiber, acrylic fiber, cellulose fiber, aramid fiber, steel fiber, and carbon fiber.
The amount of fiber used is preferably 0.1 to 2 parts per 100 parts of mortar or concrete before adding water.

  In the present invention, thickeners such as cellulose ethers and guar gums, polyacrylamides, polyethylene oxides, etc. are used as long as they do not hinder the performance of sprayed construction and hardened shotcrete. Various additives such as foaming agents, antirust agents, antifreeze agents, shrinkage reducing agents, clay minerals such as bentonite and anion exchangers such as hydrotalcite, blast furnace slow cooling slag, inorganic powder such as γ-type dicalcium silicate, It is possible to use together 1 type, or 2 or more types in the group which consists of calcium aluminates other than gypsums, such as anhydrous gypsum, ni water gypsum, and half water gypsum, and an alumina cement.

The spraying method of the present invention is not particularly limited, but a wet spraying method in which a rapid setting agent is combined and sprayed into cement concrete mixed by adding water that is pumped and mixed, or concrete in a dry state. It is possible to use a dry spraying method in which a pressure is fed and a curing accelerator is merged and sprayed before the nozzle.
When using the wet spraying method, for example, cement or cement and alumina cement, aggregates are kneaded, lightened by a predetermined amount at the plant, mixed with a mixer, and the mixed concrete is transported to the spraying point with an agitator truck. To do. In addition, there is a method in which concrete mixed with a piston-type or air-conveying-type concrete pump is transported, and mixed, mixed and sprayed onto the concrete through an insertion tube of a hardening accelerator provided in front of the nozzle.
In the case of construction by the dry spray method, for example, a predetermined amount of cement or cement and alumina cement and aggregate are weighed and mixed with a mixer without adding water. In that case, the amount of generated dust can also be suppressed by adding about 0.5 to 2% of water or a dust reducing agent. The mixed dry concrete is transported to the spraying point by an agitator truck. The obtained dry concrete may be air-conveyed with an air-conveying pump, and the curing accelerator may be mixed and mixed with the dry concrete from the hardening accelerator insertion tube provided in front of the nozzle and sprayed.
The transport of the curing accelerator is not particularly limited, but both methods are preferably sent by a plunger-type liquid pump and added to the concrete together with compressed air.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, it is not limited to these.

"Experiment 1"
Unit amount of each material, Table 2 Cement mineral compositions shown in 400 kg / ^{m 3,} fine aggregates 1058kg / ^{m 3,} coarse aggregate 710 kg / ^{m 3,} the water 232kg / ^{m 3} the shotcrete prepared was added, the The sprayed concrete was pumped by a concrete pump “MKW-25SMT” under the conditions of a spraying pressure of 0.4 MPa and a spraying speed of 10 m ³ / h. The curing accelerator A misted with compressed air of 2 m ³ / min was mixed and sprayed with concrete fed by a merging pipe connected to a position 0.6 m from the nozzle tip. The addition rate of hardening accelerator A was added so that it might become 3% by solid content with respect to cement. The change in the fluidity of the concrete before adding the hardening accelerator A and the compressive strength of the shotcrete were measured. The results are shown in Table 2.

(Materials used)
Coarse aggregate: Himekawa Sakegawa gravel, Itoigawa City, Niigata Prefecture, surface dry condition, specific gravity 2.66, maximum dimension 13mm
Fine aggregate: Himekawa Sakegawa gravel, Itoigawa city, Niigata prefecture, surface dry condition, specific gravity 2.62
Cement A: Ordinary Portland cement, commercially available 3CaO · SiO ₂ 49.6%, 2CaO · SiO ₂ 23.4%, 3CaO · Al ₂ O ₃ 8.6%, 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ 9.2%, Blaine specific surface area 3300 cm ² / g
Cement B: Early strength Portland cement Commercial product, 3CaO · SiO ₂ 63.2%, 2CaO · SiO ₂ 10.8%, 3CaO · Al ₂ O ₃ 8.8%, 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ 10.6%, Blaine specific surface area 4350 cm ² / g
Cement C: Moderate heat Portland cement Commercial product, 3CaO · SiO ₂ 42.0%, 2CaO · SiO ₂ 32.4%, 3CaO · Al ₂ O ₃ 5.7%, 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ 14.1%, Blaine specific surface area 3250 cm ² / g
Cement D: Low heat Portland cement Commercial product, 3CaO · SiO ₂ 28.2%, 2CaO · SiO ₂ 51.1%, 3CaO · Al ₂ O ₃ 2.5%, 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ 15 0.1%, Blaine specific surface area 3300 cm ² / g
Cement E: Fly ash cement type B Commercial product, 3CaO · SiO ₂ 34.3%, 2CaO · SiO ₂ 31.9%, 3CaO · Al ₂ O ₃ 8.8%, 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ 7.9%, Blaine specific surface area 3500 cm ² / g, insoluble residue 12.1%

  Cements F to H were prepared by the following method.

<Materials used>
As raw materials for cement clinker, limestone, silica and iron concentrate and coal ash, which is a clay substitute waste, were used.
Limestone: CaO 54.9%
Silica: 97.8% SiO ₂
Coal ash: Al ₂ O ₃ 27.7%
Iron concentrate: 65.5% Fe ₂ O ₃
Dihydrate gypsum: ig. loss 21.3%, CaO 31.9%, SO ₃ 45.6%
Fly ash: Commercial product JISII class equivalent

<Cement production method>
Next, a method for producing cement will be described.
The cement clinker raw materials were mixed at the blending ratio shown in Table 1 and fired at 1500 ° C. using a rotary kiln. The obtained clinker was gradually cooled, 3% of dihydrate gypsum was added in terms of SO ₃ and pulverized with a ball mill. Thereafter, fly ash was mixed with 15% of cement E and F and 12% of cement G in a blending silo to produce cement. The mineral composition was calculated from the Borg equation.

Cement F: 3CaO · SiO ₂ 50.3%, 2CaO · SiO ₂ 15.3%, 3CaO · Al ₂ O ₃ 0.5%, 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ 14.6%, insoluble Residue 15.2%, Blaine specific surface area 3200 cm ² / g
Cement G: C ₃ S 54.6%, 2CaO · SiO ₂ 14.3%, 3CaO · Al ₂ O ₃ 1.9%, 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ 10.6% Insoluble residue 14 .8%, Blaine specific surface area 3250 cm ² / g
Cement H: 3CaO · SiO ₂ 59.2%, 2CaO · SiO ₂ 5.3%, 3CaO · Al ₂ O ₃ 3.7%, 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ 17.7%, insoluble Residue 11.9%, Blaine specific surface area 3200 cm ² / g

Curing accelerator A: Aluminum sulfate aqueous solution, solid content 26.8%, commercial product

(Measuring method)
Flowability: Slump was measured according to JIS A 1101. The measurement was performed immediately after kneading and after 60 minutes at temperatures of 10 ° C., 20 ° C., and 30 ° C.
Compressive strength: The compressive strength of 1 hour and 24 hours of age is that the pin placed on the pullout formwork 25cm wide x 25cm long is covered with quick setting spray concrete from the surface of the pullout formwork, and the back side of the formwork The pin was further pulled out, 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 at the age of 28 days was obtained by spraying quick setting sprayed concrete on a mold of width 50 cm x length 50 cm x thickness 20 cm, and a specimen 5 cm in diameter x 10 cm in length taken with a core drill one day later. The compressive strength was determined by measuring with a 20-ton pressure machine. Curing up to the measurement was performed at 10 ° C, 20 ° C, and 30 ° C underwater. The specimens of sprayed concrete were collected at an outdoor test site. The temperature is 20 ° C.

"Experimental example 2"
The same operation as in Experimental Example 1 was conducted except that alumina cement was added to 100 parts of cement as shown in Table 3. The results are shown in Table 3. The fluidity was evaluated at 20 ° C. The specimens of sprayed concrete were collected at an outdoor test site. The temperature is 19 ° C.

(Materials used)
Alumina cement: Alumina cement 1

"Experiment 3"
Cement F (F), mixed cement (F-AC) prepared by adding 4 parts of alumina cement No. 1 to 100 parts of cement F and adjusting the types of hardening shown in Table 4 for 100 parts of cement The same procedure as in Experimental Example 1 was conducted except that 3 parts of the agent was added in solid content. The results are shown in Table 4. The fluidity was evaluated at 20 ° C. The specimens of sprayed concrete were collected at an outdoor test site. The temperature was 21 ° C and underwater curing was performed at 20 ° C.

(Materials used)
Curing accelerator B: Liquid curing accelerator obtained by adding 8% lithium sulfate to liquid aluminum sulfate (solid content concentration 26.8%).
Curing accelerator C: Liquid curing accelerator obtained by adding 5% triethanolamine to liquid aluminum sulfate (solid content concentration 26.8%).
Curing accelerator D: Liquid curing accelerator obtained by adding 20% sodium fluoride to liquid aluminum sulfate (solid content concentration 26.8%).
Curing accelerator E: Liquid curing accelerator obtained by adding 8% lithium sulfate and 5% triethanolamine to liquid aluminum sulfate (solid concentration 26.8%).
Curing accelerator F: Liquid curing accelerator obtained by adding 8% lithium sulfate and 20% sodium fluoride to liquid aluminum sulfate (solid concentration 26.8%).
Curing accelerator G: Liquid curing accelerator obtained by adding 20% sodium fluoride and 5% triethanolamine to liquid aluminum sulfate (solid content concentration 26.8%).
Curing accelerator H: Liquid curing accelerator obtained by adding 8% lithium sulfate, 20% sodium fluoride, 5% triethanolamine to liquid aluminum sulfate (solid content concentration 26.8%).

"Experimental example 4"
Cement F (F), mixed cement (F-AC) prepared by adding 4 parts of alumina cement No. 1 to 100 parts of cement F and adjusting the amount of hardening accelerator A in solids to 100 parts of cement The procedure was the same as in Experimental Example 1 except that the addition was made as shown in Table 5. The results are shown in Table 4. The specimens of sprayed concrete were collected at an outdoor test site. The temperature was 21 ° C and underwater curing was performed at 20 ° C.

“Experimental Example 5”
Mixing cement (F-AC) was prepared by adding 4 parts of alumina cement No. 1 to 100 parts of cement F and cement F, and setting retarders were added to these 100 parts of cement as shown in Table 5. The procedure was the same as in Experimental Example 1 except that. The results are shown in Table 6.

(Materials used)
Setting retarder: Mixture of 50 parts citric acid and 50 parts sodium carbonate

"Experimental example 6"
Mixing cement (F-AC) with unit water content of 200 kg / m ^{3 and} adding 4 parts of alumina cement No. 1 to 100 parts of cement F and cement F is prepared, and a dispersant is added to 100 parts of these cements. The test was performed in the same manner as in Experimental Example 1 except that the addition was made as shown in Table 7. The results are shown in Table 6.

(Materials used)
Dispersant: Liquid polycarboxylic acid polymer compound Commercially available product

"Experimental example 7"
The experiment was conducted except that fibers were added as shown in Table 8 to 100 parts of concrete using F-AC mixed cement (F-AC) with 100 parts of cement F and 4 parts of alumina cement 1 added to 100 parts of cement F. Performed as in Example 1. The results are shown in Table 8.

(Materials used)
Fiber: Steel fiber, 30mm length, commercial product

(Measuring method)
Bending toughness: Measured according to JSCE-G552-2007.

  According to the spraying material of the present invention and the spraying method using the same, it is possible to produce spraying concrete with low slump loss and low temperature dependency even when alumina cement with high hydration activity is contained in the concrete, and low dust Therefore, it is possible to realize spraying with low rebound and little alkali stimulation to the human body. Further, it is possible to provide a spray material with excellent setting properties, and since it is difficult to inhibit long-term strength development, it is advantageous in terms of performance and economy. In addition, since the spraying system does not require a powder transport device and can be handled with a liquid quick-setting agent pressure pump, spraying can be performed with a simple system, which is suitable for the civil engineering and construction industries.

Claims (8)

A cement containing Blaine specific surface area of 2500 cm ² / g or more insoluble residue, mineral composition calculated from Borg formula, tricalcium silicate 50-60 wt%, aluminate tribasic calcium 0-4 wt%, iron A spraying material containing 100 to 10 parts by mass of cement of 10 to 18% by mass of tetracalcium aluminate, an aggregate, and 0.5 to 10 parts by mass in terms of solid content of a hardening accelerator containing aluminum sulfate. The spraying material according to claim 1, wherein 1 to 20 parts by mass of alumina cement is contained with respect to 100 parts by mass of cement. The spraying material according to claim 1 or 2, comprising one or more selected from alkali metal salts, amine compounds, and fluorine compounds. The hardening accelerator containing aluminum sulfate contains 1 type, or 2 or more types chosen from an alkali metal salt, an amine compound, and a fluorine compound, The any one of Claims 1-3 characterized by the above-mentioned. The spraying material described. The spraying material according to any one of claims 1 to 4, further comprising a setting retarder. The spraying material according to any one of claims 1 to 5, further comprising a dispersant. The spray material according to any one of claims 1 to 6, further comprising a fiber. A cement concrete or mortar is produced by mixing spray materials other than the hardening accelerator containing aluminum sulfate with water, pumping it, and joining the hardening accelerator containing compressed air and aluminum sulfate before the nozzle. The spraying method using the spraying material according to any one of claims 1 to 7, wherein the spraying method is performed by mixing and spraying.