JP2002249363A - Spray material and spray technique using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spray material giving cement concrete which excels in feeding ability by pressure of a pump and quick setting cement concrete which excels in strength development and freezing and thawing resistance. SOLUTION: The spray material contains a hydraulic material, aggregate, an air-entraining agent, cement concrete having water and a quick setting admixture having aluminum sulfate. The air amount in cement concrete is preferably 7% or more, grain size of powder is preferably 3,000 square cm/g or more by a Blaine value. The spray material may include fiber, a viscosity modifier and fine powder, the quick setting admixture is preferably liquid and may include an alkali metal carbonate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to prevent a ground surface or a slope where a ground surface is exposed from collapsing during tunnel excavation work for roads, railways, and headraces, and to provide a concrete structure. The present invention relates to a spray material used for repairing the like. In the present invention, mortar and concrete are collectively referred to as cement concrete, and cement concrete containing no water is dry cement concrete.
Cement concrete containing water is called wet cement concrete.

[0002]

2. Description of the Related Art Conventionally, in the excavation of tunnels for roads and railways, a spraying method using a quick-setting concrete mixed with a quick-setting agent and concrete as a spraying material is used in order to prevent the exposed ground surface from collapsing. It has been implemented. In this method, concrete is usually prepared by mixing cement, aggregate, and water in a concrete manufacturing facility installed at the construction site, transported to the spraying site by an agitator truck, and air-conveyed by a spraying machine. The NATM method in which a quick-setting agent conveyed by air from one of the mixing pipes provided on the way is combined and mixed, and is sprayed as quick-setting spray concrete.

In the after-blowing after excavation by the TBM method, wet mortar is prepared by continuously mixing dry mortar in which a hydraulic material and an aggregate are previously mixed with water by a mixer pump of a continuous kneading type, and is fed and pumped. Then, a method of mixing and mixing with a liquid quick-setting admixture and spraying as a quick-setting spray mortar has been implemented.

In spraying on a slope, a liquid quick-setting agent mainly composed of water glass is combined with concrete to prevent dripping of the mortar sprayed by the free frame method, and the quick-setting spray concrete is obtained. The spraying method has been implemented.

[0005]

In recent years, early deterioration of concrete has become a problem, and there has been a demand for improvement in durability such as freeze-thaw resistance of quick-setting sprayed concrete. However, concrete structures at the tunnel entrance in cold regions below the freezing point, concrete structures exposed to the open air, and quick-setting shotcres sprayed on slopes exposed to the open air have a freeze-thaw resistance. Was also inferior.

[0006] When the water-cement ratio is reduced to improve the freeze-thaw resistance, there is a problem that the pumping performance is deteriorated.

As a result of various studies to solve these problems, the inventor of the present invention has found that the use of a specific spraying material can solve the problems and has completed the present invention.

[0008]

That is, the present invention relates to a cement concrete containing a hydraulic material, an aggregate, an air entraining agent and water, and a quick-setting agent containing an alkali metal aluminate. Is a spraying material having an air content of cement concrete of 7% or more, further comprising a fine powder, and further comprising a viscosity modifier. The spraying material further comprises fibers, the spraying material having a particle size of fine particles of 3000 cm ² / g or more in a Blaine value, and the quick-setting agent is an alkali metal carbonate. The spray material comprises a salt, and the quick-setting agent is a liquid quick-setting agent. Then, the cement concrete containing the hydraulic material, the aggregate, the air entraining agent, and water is pumped, and the quick-setting agent containing aluminum sulfate is mixed and mixed during the pumping to form the quick-setting cement concrete. A spraying method characterized by preparing and spraying.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

According to the present invention, a cement concrete is prepared by kneading a hydraulic material, an aggregate, an air entraining agent, and water,
A quick setting cement concrete is prepared by mixing and mixing a quick setting agent to the cement concrete, and the quick setting cement concrete is sprayed as a spray material. In particular, by increasing the amount of air by using an air entraining agent, the unit mass of cement concrete is reduced, so that even when the water / powder ratio is small, the pumpability is improved, and the freeze-thaw resistance is improved. This has the effect. Here, the powder is a hydraulic material,
And the total of fine powder and viscosity modifier used as needed. In addition, since excess air escapes from the quick-setting cement concrete due to the impact at the time of spraying, there is little adverse effect such as a significant decrease in strength development. Further, the spray material of the present invention has less dust and rebound.

The hydraulic material used in the present invention includes cements, mixtures of cements and calcium aluminates, cements, calcium aluminates,
And a mixture of gypsum. Among them, a mixture of cements and calcium aluminates, or a mixture of cement, calcium aluminates, and gypsum is preferable in terms of excellent reaction activity, and a mixture of cement, calcium aluminates, and gypsum is preferred. More preferred.

[0012] As cements, various Portland cements such as ordinary, fast, moderate heat, super fast, and low heat, etc.
Various mixed cements in which fly ash, blast furnace slag, and the like are mixed with these Portland cements, fine particle cements, and the like are given.

The calcium aluminate used in the present invention is obtained by mixing a raw material containing calcia and a raw material containing alumina and performing a heat treatment such as firing in a kiln or melting in an electric furnace. Is a general term for substances having hydration activity with CaO and Al ₂ O ₃ as main components.
And / or part of Al ₂ O ₃ is an alkali metal oxide, an alkaline earth metal oxide, silicon oxide, titanium oxide, iron oxide, an alkali metal halide, an alkaline earth metal halide, an alkali metal sulfate, And substances substituted with alkaline earth metal sulfates, or CaO and Al ₂ O ₃
Is a substance in which a small amount of these are dissolved in a substance having as a main component. The mineral form may be either crystalline or amorphous.

Among calcium aluminates, C ₁₂ A ₇ (C is an abbreviation for CaO, A is A
l ₂ O ₃ ) is preferable, and amorphous C ₁₂ A ₇ is more preferable.

The amount of the calcium aluminate used is preferably 0.5 to 8 parts by mass, more preferably 2 to 7 parts by mass, based on 100 parts by mass of the cements. If the amount is less than 0.5 part by mass, the initial setting may not be easily promoted. If the amount exceeds 8 parts by mass, the fluidity of the cement concrete may be impaired.

The gypsum used in the present invention is used for further improving the initial and long-term strength development. The gypsum includes hemihydrate gypsum, dihydrate gypsum, and anhydrous gypsum, and one or more of these may be used. Among these, anhydrous gypsum is preferable in terms of strength development.

The amount of gypsum used is preferably 20 to 300 parts by mass, more preferably 50 to 200 parts by mass, based on 100 parts by mass of calcium aluminates. If it is less than 20 parts by mass, it may not contribute to the improvement of the initial and long-term strength development properties, and if it exceeds 300 parts by mass, the initial setting properties may be impaired.

The aggregate used in the present invention includes river sand, mountain sand, sea sand, lime sand and the like. Aggregate may be used by mixing with hydraulic material or water at the spraying site, or the dried aggregate is mixed with hydraulic material to form a premix type dry cement concrete, and this dry cement Concrete may be transported to the site.

The particle size of the aggregate is 2.5 mm in terms of pumpability and the like.
Or less, more preferably 1.5 mm or less. 2.5
If it exceeds mm, the pumpability will decrease and the rebound rate when sprayed may increase.

The amount of aggregate used is preferably 150 to 300 parts by mass, and more preferably 180 to 300 parts by mass with respect to 100 parts by mass of the hydraulic material.
270 parts by weight are more preferred. If the amount is less than 150 parts by mass, the drying shrinkage resistance may decrease. If the amount exceeds 300 parts by mass, the rebound rate when sprayed may increase.

The air entraining agent used in the present invention refers to a cement admixture for introducing air into wet cement concrete obtained by mixing a hydraulic material, an aggregate, and water. As the air entraining agent, a commercially available AE agent or an AE water reducing agent having water reducing performance can be used. Examples of the air entraining agent include carboxylic acid compounds, soaps, sulfates and other anionic surfactants, ethers and ester ethers and other nonionic surfactants, betaines and imidalizone betaines. And an amphoteric surfactant, a cationic surfactant and the like. Among these, anionic surfactants are preferred because they are generally easily available.

The amount of air entrainer used is
0.001 to 0.3 parts by mass, preferably 0.005 to 0.2 parts by mass, based on parts by mass. 0.0
If it is less than 01 parts by mass, the amount of air becomes small, the unit volume mass of cement concrete becomes large, and the pumping resistance becomes large, so that the pumping ability becomes poor, and the freeze-thaw resistance may not be improved. If the amount exceeds the part, the strength developability may decrease.

The air content of the cement concrete used in the present invention is at least 7%, preferably 10 to 25%,
15-20% is more preferable. If it is less than 7%, the unit volume mass of the cement concrete becomes large, the pumping performance is deteriorated, and the freeze-thaw resistance of the quick-setting cement concrete may not be improved. There is a risk.

Further, in the present invention, it is preferable to use a fine powder in order to improve the pumpability and the adhesive property at the time of spraying.

The particle size of the fines, from the viewpoint of improving the adhesion properties at the time of pumpability and spraying, preferably 3000 cm ² / g or more in Blaine value, 7000 cm ² / g or more is more preferable.

Examples of the fine powder include beidellite, bentonite, metakaolin, kaolinite, halloysite, montmorillonite, and layered aluminosilicates as main components.
Pyrophyllite, vermiculite, mica, chlorite,
Clay minerals such as saponite, sepiolite, and acid clay, fine slag, fine fly ash, silica fume, and limestone powder. Among these,
From the viewpoint of pumpability, fluidity, and adhesion characteristics at the time of spraying, one or two or more kinds selected from the group consisting of silica fume, limestone powder, and clay mineral are preferred, and silica fume is more preferred.

The amount of the fine powder to be used is preferably 0.5 to 5 parts by mass, more preferably 1 to 3 parts by mass, per 100 parts by mass of the hydraulic material. If the amount is less than 0.5 part by mass, the adhesion properties during spraying may not be improved, and if it exceeds 5 parts by mass, the fluidity may be reduced.

Further, in the present invention, it is preferable to use a viscosity modifier in order to impart viscosity to the cement concrete and to improve the adhesion characteristics at the time of spraying.

As the viscosity modifier used in the present invention, a high molecular compound having hydrophilicity can be mentioned. Examples of hydrophilic polymer compounds include celluloses such as carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, methylethylcellulose, and ethylcellulose; amylose, agar, alginic acid, sodium alginate, pullulan, and polysaccharides such as guar gum; Various derivatives, polyvinyl alcohol, and
Examples include polyethylene oxide. Among these, it is excellent in adhesion characteristics and it is difficult to inhibit strength development,
Cellulose is preferred, and methylcellulose is more preferred.

The amount of the viscosity modifier used is based on 100 parts by mass of the hydraulic material and the fine powder used as required.
0.02 to 0.3 part by mass is preferable, and 0.08 to 0.2 part by mass.
Parts by mass are more preferred. If the amount is less than 0.02 parts by mass, it may be difficult to impart viscosity. If the amount exceeds 0.3 parts by mass, the fluidity may be excessively reduced and the pumpability may be impaired.

Further, in the present invention, it is preferable to use fibers in order to improve the bending characteristics of the quick-setting cement concrete hardened by spraying and to prevent mortar from falling due to peeling or the like. The fibers are mainly added to the cement concrete side in advance, but may be added to the quick setting agent side in advance.

Examples of the fibers include steel fibers, glass fibers, and polymer fibers. Among these, polymer fibers are preferable in that they have good dispersibility with hydraulic materials and improve bending properties. Vinylon fiber,
Examples include polypropylene fiber, polyethylene fiber, polyacrylonitrile fiber, and aramid fiber. Among these, vinylon fibers are preferred in view of bending toughness.

The fiber length of the fiber is preferably 2 to 15 mm,
-10 mm is more preferred. If it is less than 2 mm, the bending properties may not be improved, and if it exceeds 15 mm, the pumpability of the cement concrete may be impaired.

The amount of the fibers used is preferably 0.05 to 1 part by mass, and more preferably 0.1 to 1 part by mass, based on 100 parts by mass of the hydraulic material, the aggregate, and the viscosity modifier and the fine powder used if necessary.
-0.8 parts by mass is more preferred. If the amount is less than 0.05 part by mass, the bending properties may not be improved. If the amount exceeds 1 part by mass, the fluidity of the cement concrete may be reduced, and the pumpability may be impaired.

The quick setting agent used in the present invention contains an alkali metal aluminate (hereinafter referred to as aluminate).
Among the quick-setting agents, a liquid quick-setting agent is preferable because the components in the quick-setting agent can be uniformly dispersed and the handling is easy. here,
Liquid quick-setting agents containing an aluminate include aqueous solutions and suspensions.

Examples of the aluminate include sodium aluminate, lithium aluminate and potassium aluminate. Among these, potassium aluminate is preferred because it has a high solubility in water, so that it has good initial setting, strength development, and adhesion properties at the time of spraying, and has little dripping and rebound.

In the present invention, an aluminate and an alkali metal carbonate (hereinafter, referred to as a carbonate) may be used in combination as a liquid quick-setting agent in order to further improve the strength expression.

Examples of the carbonate include a carbonate such as sodium carbonate, lithium carbonate and potassium carbonate, and a bicarbonate such as sodium bicarbonate, lithium bicarbonate and potassium bicarbonate. Among them, carbonates are preferable because of high solubility in water, so that initial coagulation, strength development, and adhesion properties at the time of spraying are good, and sag and rebound are small, and potassium carbonate and / or sodium carbonate are preferable. Use is more preferred.

The amount of the carbonate used is preferably 5 to 50 parts by mass, more preferably 10 to 30 parts by mass, per 100 parts by mass of the aluminate. If the amount is less than 5 parts by mass, no improvement in strength development may be observed, and if it exceeds 50 parts by mass, the initial setting may be delayed.

The component concentration in the liquid quick-setting admixture is 30 to 65%
Is preferable, and 40 to 55% is more preferable. If it is less than 30%, there is a possibility that it does not contribute to the improvement of the initial setting and strength development, and if it exceeds 65%, the viscosity of the liquid quick-setting agent increases, the pumpability of the liquid quick-setting agent decreases, and the liquid quick-setting agent decreases. And cement concrete are difficult to mix sufficiently, and it may be difficult to handle the liquid quick-setting admixture.

The amount of the quick setting agent is preferably from 0.2 to 10 parts by mass, more preferably from 0.5 to 8 parts by mass, based on 100 parts by mass of the hydraulic material. When the amount is less than 0.2 parts by mass, initial setting is difficult to be promoted, the strength development property is reduced, the adhesion characteristics at the time of spraying are reduced, and dripping and rebound may increase. This may cause solidified matter to adhere to the inside of the pipe or the nozzle, resulting in a decrease in long-term strength development.

Further, in the present invention, a water reducing agent or a setting retarder may be used in combination.

The water powder ratio (W / P) of the cement concrete of the present invention is preferably 10 to 25%, more preferably 14 to 23%. If it is less than 10%, the viscosity of the cement concrete is so large that the spraying workability and pumpability may be reduced, and if it exceeds 25%, the strength development and initial setting may be adversely affected. In addition, the water in the liquid quick-setting admixture is not considered for the water here.

As a method for preparing the spray material of the present invention, for example, the following method can be mentioned. The quick-setting agent is pumped by a plunger pump or the like to the outside of a double pipe having several holes or grooves in the inner wall surface. Also, cement concrete is pumped inside the double pipe. The quick-setting agent mixed with air and formed into a mist is pressure-fed from the outside of the double pipe to the inside of the double pipe through the hole or groove of the double pipe to join and mix with the cement concrete, and quickly set. Sprayed as cement cement.

[0045]

The present invention will be described below in detail with reference to experimental examples.

Experimental Example 1 Dry cement mortar was prepared by mixing 100 parts by weight of the hydraulic material shown in Table 1 and 200 parts by weight of aggregate. Into this dry cement mortar, 100 parts by mass of hydraulic material, an air entraining agent in parts by mass shown in Table 1, 2 parts by mass of fine powder,
0.1 parts by mass of a viscosity modifier with respect to a total of 100 parts by mass of hydraulic material and fine powder, and 0.5 parts by mass with respect to a total of 100 parts by mass of hydraulic material, aggregate, viscosity modifier and fine powder The fiber of the part and water having a water powder ratio of 20% were mixed to prepare a wet cement mortar. The air content and the unit mass of the obtained wet cement mortar containing no quick-setting agent were measured. Table 1 shows the results. Experimental example 2
Hereinafter, to this wet cement mortar, 5 parts by mass of 100 parts by mass of an aluminate and 15 parts by mass of a carbonate and having a component concentration of 45% in terms of components are added to 100 parts by mass of the hydraulic material. And kneaded for 10 seconds to prepare a quick-setting cement mortar.

(Materials used) Hydraulic material a: Early-strength Portland cement (specific gravity 3.1)
4, a commercial product) 100 parts by mass, 2 parts by mass of calcium aluminates and 2 parts by mass of gypsum Hydraulic material b: ordinary Portland cement, specific gravity 3.1
6. Commercial product Hydraulic material c: Early strength Portland cement (specific gravity 3.1
4, a commercial product) A mixture comprising 100 parts by mass and 2 parts by mass of calcium aluminates Calcium aluminates: main component C ₁₂ A ₇ , amorphous,
Blaine specific surface area 5900 cm ² / g Gypsum: Anhydrite, commercially available Aggregate: Lime sand from Aomi-cho, Niigata, particle size 1.5 mm or less, specific gravity 2.67 Fiber: vinylon fiber, fiber length 6 mm, commercially available viscosity modifier : Methylcellulose, Commercial product Fine powder: Silica fume, specific surface area 7000 cm ² / g or more, Commercial product Aluminate: Potassium aluminate, Commercial product Carbonate: Potassium carbonate, Commercial product Air entraining agent: Modified alkyl carboxylic acid compound-based anionic activity Agents, commercial products

(Measurement method) Air amount: For a wet cement mortar containing no quick-setting agent, JIS A1
It measured according to 128. Unit volume mass: For a wet cement mortar containing no quick-setting agent, measure the mass of the mortar used in the measurement of the amount of air, and divide the mass of the obtained mortar by the volume of the mortar air meter that has been measured in advance. It was calculated by the following.

[0049]

[Table 1]

Experimental Example 2 In a dry cement mortar, 0.05 parts by mass of an air entraining agent with respect to 100 parts by mass of hydraulic material a, 2 parts by mass of fine powder, and 0 parts by mass with respect to 100 parts by mass of the total of hydraulic material and fine powder. .
1 part by mass of the viscosity modifier, and 100 parts by mass of the hydraulic material, the aggregate, the viscosity modifier, and the fine powder with respect to 100 parts by mass of the fibers shown in Table 2 and water having a water powder ratio of 20%. Mix to prepare wet cement mortar, aluminate 1
Of 100 parts by mass and 15 parts by mass of carbonate,
% Of liquid quick-setting agent is added to 100 parts by mass of hydraulic material in terms of component to prepare 5 parts by mass of quick-setting cement mortar, and the amount of air is measured with respect to the obtained wet cement mortar containing no quick-setting agent The procedure was performed in the same manner as in Experimental Example 1 except that the toughness coefficient of the obtained quick-setting cement mortar was measured. Table 2 shows the results.

(Measurement method) Flexural toughness coefficient: For quick setting cement mortar, JS
It measured according to CE-G552. Measuring material age is 28
Day.

[0052]

[Table 2]

Experimental Example 3 In a dry cement mortar, 0.05 parts by mass of an air entraining agent, 100 parts by mass of a fine powder, and 100 parts by mass of the hydraulic material and the fine powder shown in Table 3 were added to 100 parts by mass of the hydraulic material a. On the other hand, 0.1 parts by mass of a viscosity modifier, 0.5 parts by mass of fiber with respect to a total of 100 parts by mass of hydraulic material, aggregate, viscosity modifier, and fine powder, and water powder ratio of 20% Was mixed with water to prepare a wet cement mortar, and the same procedure as in Experimental Example 1 was carried out except that the air amount and the mortar flow of the obtained wet cement mortar containing no quick setting agent were measured. Table 3 shows the results.

(Measurement Method) Mortar Flow: A wet cement mortar containing no quick-setting agent was measured according to JISA5201.

[0055]

[Table 3]

Experimental Example 4 In dry cement mortar, 0.05 parts by mass of an air entraining agent per 100 parts by mass of hydraulic material a, 0 parts by mass of fine powder of 2 parts by mass, and 100 parts by mass of hydraulic material and fine powder .
1 part by mass of the viscosity modifier, and 0.5 with respect to a total of 100 parts by mass of the hydraulic material, the aggregate, the viscosity modifier, and the fine powder.
A wet cement mortar is prepared by mixing parts by mass of fiber and water having a water powder ratio of 20%.
A rapid-setting cement mortar was prepared by adding a liquid quick-setting agent consisting of 15 parts by mass and 15 parts by mass of a carbonate and having a component concentration of 45% to 100 parts by mass of the hydraulic material in terms of components as shown in Table 4 in terms of components. The procedure was performed in the same manner as in Experimental Example 1 except that the amount of air was measured for the obtained wet cement mortar containing no quick setting agent, and the setting properties and prismatic compressive strength of the obtained quick setting cement mortar were measured. Table 4 shows the results.

(Measurement method) Setting properties: A liquid quick-setting agent was mixed at 20 ° C.
28. With regard to the quick-setting cement mortar prepared by kneading for 10 seconds, the time from the quick filling into the mold until the penetration resistance of the proctor reaches 3.5 N / mm ² is the first time.
The time required to reach 0 N / mm ² was defined as the end. Prismatic compression strength: Quick-setting cement mortar prepared after cooling all material temperatures to 5 ° C. in advance
Packing while shaking into the form of cm × 4cm × 16cm,
Cured at 20 ° C until the specified age. Curing is performed at a temperature of 20.
Curing in the air at 60 ° C and 60% humidity.
According to IS R5201.

[0058]

[Table 4]

Experimental Example 5 100 parts by mass of hydraulic material a, 200 parts by mass of aggregate, fine powder 2
Parts by mass, the viscosity modifier shown in Table 5 with respect to a total of 100 parts by mass of the hydraulic material and the fine powder, and 0.5 with respect to a total of 100 parts by mass of the hydraulic material, the aggregate, the viscosity modifier and the fine powder.
A dry cement mortar consisting of parts by mass of fiber was prepared. This dry cement mortar was put into a G4 pump manufactured by PET Co., Germany of a continuous kneading and pressure feeding system. Next, water mixed with an air entrainer in an amount of 0.05 part by mass with respect to 100 parts by mass of the hydraulic material a is mixed with dry cement mortar so as to have a water powder ratio of 20%, and kneaded continuously. Prepare wet cement mortar, inner diameter 25.4mm
Was pumped through 10 m of piping. The discharge capacity at this time was 2.1 m ³ / hr. On the other hand, aluminate 100
5 parts by mass of a liquid quick-setting admixture consisting of 15 parts by mass of a carbonate and 15 parts by mass of a carbonate, and having a component concentration of 45%, is mixed with 100 parts by mass of hydraulic material in terms of a component. A water-soluble cement mortar was prepared and sprayed from a nozzle. The adhesive properties of the resulting quick-setting cement mortar were measured. Table 5 shows the results.

(Measurement method) Adhesion characteristics: 4 m in height x 4 m in width x 5 in length with nozzle fixed
m was sprayed onto the side wall of the m-simulated tunnel for 15 seconds, and the distance from the sprayed side wall to the top of the quick-setting cement mortar adhering thereto was measured to determine the adhesion characteristics.

[0061]

[Table 5]

Experimental Example 6 100 parts by mass of hydraulic material a, 200 parts by mass of aggregate, fine powder 2
Parts by mass, 0.1 part by mass of the viscosity modifier with respect to 100 parts by mass of the hydraulic material and the fine powder, and 0 parts by mass with respect to 100 parts by mass of the hydraulic material, the aggregate, the viscosity modifier and the fine powder. A dry cement mortar composed of 0.5 parts by mass of fibers is prepared, and water mixed with 0.05 parts by mass of an air entraining agent is mixed with 100 parts by mass of the hydraulic material a so as to have a water powder ratio of 20%. To prepare a wet cement mortar,
A quick-setting cement mortar consisting of 100 parts by mass of an aluminate and 15 parts by mass of a carbonate and having a component concentration of 45% and having a component concentration of 45% added to 100 parts by mass of a hydraulic material in terms of components as shown in Table 6 in terms of components. Was carried out in the same manner as in Experimental Example 5 except that the sag and the rebound rate of the obtained quick-setting cement mortar were measured. Table 6 shows the results.

(Measurement Method) Sagging: Quick setting cement mortar was manufactured in an arc shape with an iron plate at a pumping speed of 2.1 m ³ / h for 2 minutes.
The state of being sprayed on the simulated tunnel having a width of 2.5 m was observed. When no dripping occurred, it was evaluated as ○, when slight dripping occurred, as Δ, and when much dripping occurred, as X. Rebound rate: 2.1 m ³ / h of quick setting cement mortar
Was sprayed onto a simulated tunnel 3.5 mm high x 2.5 m wide made of an iron plate at a pumping speed of 2 minutes. Thereafter, (rebound rate) = (mass of quick-setting cement mortar dropped without adhering to the simulated tunnel) / (mass of quick-setting cement mortar sprayed on the simulated tunnel) × 100
(%).

[0064]

[Table 6]

Experimental Example 7 100 parts by mass of hydraulic material a, 200 parts by mass of aggregate, fine powder 2
Parts by mass, 0.1 part by mass of the viscosity modifier with respect to 100 parts by mass of the hydraulic material and the fine powder, and 0 parts by mass with respect to 100 parts by mass of the hydraulic material, the aggregate, the viscosity modifier and the fine powder. A dry cement mortar composed of 0.5 parts by mass of fiber is prepared, and water mixed with 100 parts by mass of hydraulic material and an air entraining agent of parts by mass shown in Table 7 is adjusted to 20% in water powder ratio. A wet cement mortar is prepared by mixing with a dry cement mortar, and 100 parts by mass of an aluminate and 15 parts by mass of a carbonate are used. A quick setting cement mortar was prepared by adding 5 parts by mass in terms of conversion, the pressure was measured for the obtained wet cement mortar not containing the quick setting agent to evaluate the pumping resistance, and the resulting quick setting cement mortar was added. Except that measured freeze-thaw resistance and columnar compressive strength, were conducted in the same manner as in Experimental Example 5. Table 7 shows the results.

(Measurement method) Pressure: A pressure gauge is provided at the outlet of the G4 pump to measure the pressure during the pressure feeding when wet cement mortar containing no quick-setting agent is pumped through a 10 m pipe with an inner diameter of 25.4 mm. did. Freeze-thaw resistance: The obtained quick-setting cement mortar is sprayed on a box form having a length of 50 cm x a width of 50 cm x a thickness of 20 cm, and then cut into a prism having a length of 40 cm x a width of 10 cm x a thickness of 10 cm. The specimen was used. Using this specimen,
The freeze-thaw test was measured according to JSCE-G501. The relative dynamic elastic modulus was measured every 15 cycles, and the number of cycles at which the relative dynamic elastic modulus showed 60% or less was defined as freeze-thaw resistance. Cylindrical compressive strength: The obtained quick setting cement mortar
After spraying on a box form having a size of 0 cm × 50 cm × 20 cm in thickness, a cylinder having a diameter of 5 cm × a height of 10 cm was formed to obtain a specimen. Using this specimen, the compression strength test was conducted according to JIS.
A was measured according to A1108.

[0067]

[Table 7]

Experimental Example 8 100 parts by mass of hydraulic material a, 200 parts by mass of aggregate, fine powder 2
Parts by mass, 0.1 part by mass of the viscosity modifier with respect to 100 parts by mass of the hydraulic material and the fine powder, and 0 parts by mass with respect to 100 parts by mass of the hydraulic material, the aggregate, the viscosity modifier and the fine powder. A dry cement mortar composed of 0.5 parts by mass of fibers is prepared, and water mixed with 0.05 parts by mass of an air entraining agent is mixed with 100 parts by mass of the hydraulic material a so as to have a water powder ratio of 20%. To prepare a wet cement mortar,
A quick-setting cement mortar was prepared by adding 100 parts by mass of an aluminate and 15 parts by mass of a carbonate, and adding 5 parts by mass of a liquid quick setting agent having a component concentration of 45% in terms of components to 100 parts by mass of a hydraulic material. , Except that the mortar pumpability was measured for the resulting cement mortar containing no quick setting agent, and that the obtained quick setting cement mortar was used to measure the clogging state of the nozzle, the amount of dust generated, and the drying shrink resistance, Performed in the same manner as in Experimental Example 5. Table 8 shows the results.

(Measurement method) Mortar pumpability: When wet cement mortar containing no quick-setting agent is pumped and the mortar is continuously discharged from the end of the hose, the discharge is possible, but discontinuous discharge is slightly observed. Was evaluated as "poor", and discontinuous discharge was increased, and pressure resistance was applied, and the hose pulsated. Nozzle clogging condition: After rapidly setting cement mortar was sprayed from the nozzle for 4 minutes, the inside of the nozzle was observed, and when 30% or more of the internal cross-section was closed, x: 10 to 30 of the internal cross-section
% Was closed, and less than 10% of the internal cross section was closed. Amount of dust generated: Rapid-setting cement mortar was formed in an arched form from an iron plate at a pumping speed of 2.1 m ³ / h for 4 minutes.
It was sprayed from the tip of the nozzle onto the side of the simulated tunnel having a size of 5 m × 2.5 m. The amount of dust generated was measured every minute by a digital dust meter at a fixed position 3 m before the nozzle tip. The amount of dust generated was indicated by the average of the measured values obtained. Drying shrinkage resistance: The obtained quick-setting cement mortar is sprayed on a triple mold having a length of 4 cm, a width of 4 cm and a thickness of 16 cm.
The removed specimen was used as a test specimen. Using this specimen, a length change test was performed. Specimens were heated at a temperature of 20 ° C and a humidity of 60%.
Cured in the air under the conditions described above, and the change in length at a given age was measured in accordance with JIS A 1129, dial gauge method, and the resulting product was regarded as dry shrinkage resistance.

[0070]

[Table 8]

[0071]

When the spraying material of the present invention is used, since a large amount of air is mixed in, the mass per unit volume is small, and a cement concrete excellent in pumpability can be prepared. Furthermore, when a liquid quick-setting admixture is used, the amount of dust generated is smaller than that of a powder quick-setting admixture, and a spray material excellent in strength development can be obtained. Further, the quick-setting cement concrete obtained by mixing the cement concrete and the quick-setting admixture is excellent in freeze-thaw resistance since air having an appropriate size and amount is mixed therein. Further, the spray material of the present invention has an effect of reducing dust and rebound.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C04B 24:04 C04B 24:04 22:08 22:08 Z 20:00 20:00 B 24:38 24:38 C 16 : 06 16:06 A 22:10) 22:10) 103: 12 103: 12 103: 30 103: 30 111: 70 111: 70 111: 72 111: 72 F term (reference) 2D055 BA06 DB00 KA08 LA10 4G012 PA10 PA24 PB04 PB05 PB08 PB11 PB16 PB40 PC02 PC06 PE01

Claims (9)

[Claims] 1. A spray material comprising a cement concrete containing a hydraulic material, an aggregate, an air entraining agent, and water, and a quick-setting agent containing an alkali metal aluminate. 2. The spray material according to claim 1, wherein the air content of the cement concrete is 7% or more. 3. The spray material according to claim 1, further comprising fine powder. 4. The spray material according to claim 1, further comprising a viscosity modifier. 5. The method according to claim 1, further comprising a fiber.
5. The spray material according to one of the four items. 6. The fine powder has a particle size of 3000 cm in Blaine value.
The spray material according to claim 3, which is not less than ² / g. 7. The spray material according to claim 1, wherein the quick-setting agent further comprises an alkali metal carbonate. 8. The quick-setting agent according to claim 1, wherein the quick-setting agent is a liquid quick-setting agent.
The spray material according to any one of the preceding claims. 9. A cement concrete containing a hydraulic material, an aggregate, an air entraining agent, and water is pumped, and a quick-setting agent containing an alkali metal aluminate is mixed and mixed during the pumping. A spraying method comprising preparing and spraying quick setting cement concrete.