JPH10324553A - Spraying material and spraying method using the material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a spraying material capable of being applied with the generation of dust reduced as compared with the case when a powdery accelerator is mixed with cement concrete and excellent in initial and long-range strength development by mixing a cement concrete contg. cement and gypsum with a slurry contg. the powdery accelerator to constitute the spraying material. SOLUTION: A cement concrete contg. 100 pts.wt. of cement and 1-25 pts.wt. of gypsum is mixed with a slurry consisting of 100 pts.wt. of accelerator and 5-300 pts.wt. of water to constitute the spraying material. In this case, 100 pts.wt. of cement is preferably mixed with 2-25 pts.wt. of the slurry, expressed in terms of solid. Further, alkali metal aluminate, alkali metal carbonate, etc., are jointly used as a setting accelerator to promote the setting of the cement concrete.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spraying material to be sprayed on an exposed ground surface in a tunnel such as a road, a railway, and a headrace, and a spraying method using the same.

[0002]

2. Description of the Related Art Conventionally, a method of spraying quick-setting concrete in which a quick-setting agent is mixed with concrete has been performed in order to prevent collapse of an exposed ground such as a tunnel excavation (Japanese Patent Publication No. Sho 6).
0-4149). In this construction method, usually, in a measuring and mixing plant installed at the excavation work site, cement, aggregate, and water are mixed to prepare shotcrete, transported by an agitator truck, pumped by a concrete pump, and provided on the way. This is a method of mixing with a quick-setting agent pumped from the other side by a confluent pipe and spraying it as a quick-setting sprayable concrete on the ground surface to a predetermined thickness. Calcium aluminate, alkali aluminate,
And simple mixtures such as alkali carbonates and the like (JP-A-64-51351, JP-B-56-274).
No. 57, Japanese Patent Application Laid-Open No. 61-26538, Japanese Patent Application Laid-Open
Publication No. 3-210050).

[0003]

However, since the quick-setting agent used in the quick-setting spray concrete is in powder form, the quick-setting agent and the quick-setting agent are pneumatically fed, mixed, and discharged from the tip of the spray nozzle. When this is done, there is a problem that the powder is scattered in the air in a powder state without being mixed well, and the amount of dust increases. For this reason, the working environment is deteriorated, and there is a risk of rough skin and pneumoconiosis. Also, a method is known in which a quick-setting agent slurry containing calcium aluminate, gypsum and water as main components is pressure-fed and mixed and mixed with concrete (Japanese Patent Publication No. 57-10058 and Japanese Patent Publication No. 57-10059). Gazette).

[0004] However, in the method using the quick-setting agent slurry, although the amount of dust is small, at least 30 to 6 to obtain the quick-setting agent slurry by a batch method.
It is necessary to add a setting retarder so as not to cause the 0th-percentile gelation. In this case, there is a problem that the initial strength development, which is a characteristic of the quick-setting agent, may be reduced.
Also, the concentration of the quick-setting agent slurry, the quality of the kneading water at the construction site,
In addition, there is a problem that the kneading time depends on the material and the material, and it is difficult to adjust the kneading time. As a result of various studies on the above problems, the present inventors have obtained knowledge that can solve the above problems by using a specific spraying material, and have completed the present invention.

[0005]

That is, the present invention relates to a cement concrete containing cement and gypsum,
A spray material characterized by being mixed with a quick-setting agent slurry containing a powdery quick-setting agent, and the spraying material further comprising a setting accelerator. A spray retarder, a setting retarder, a water reducing agent, a thickener, a fibrous substance, and one or more admixtures selected from the group consisting of ultrafine powders. The spray material is characterized in that the fine aggregate ratio of cement concrete is 70% or more, and the maximum size of the coarse aggregate is 10 mm or less. Then, at a position before the confluence point where the cement concrete is merged and mixed, the quick-setting agent slurry is air-poured by compressed air, and then the air-pressed quick-setting slurry and cement concrete are merged and mixed. Spraying method wherein the quick-setting slurry and compressed air are mixed within 5 m from the confluence of the cement concrete and the quick-setting slurry fed by air. The spraying method is characterized in that the binder and the cement are mixed within 2 minutes after the binder and water are mixed to form the binder.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the present invention, cement mortar, dry cement mortar, concrete, and dry concrete are collectively referred to as cement concrete.

As the cement used in the present invention, there are various portland cements which are usually commercially available, such as ordinary, fast, moderate heat and ultra fast, and various types of cement obtained by mixing these portland cements with fly ash or blast furnace slag. Examples thereof include mixed cement and fluorocement containing fluorocalcium aluminate, which may be used after pulverized. Of these, ordinary Portland cement is preferred because of its good pumpability after kneading cement concrete. When using the early-strength Portland cement, the slump is greatly reduced, and the pumping property after kneading the cement concrete may be reduced.

[0008] The gypsum used in the present invention is used for improving strength development. Examples of the gypsum include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum, and one or more of these may be used in combination. Among them, anhydrous gypsum is preferred from the viewpoint of strength development. The particle size of the gypsum is generally good for use in cement, for example, preferably about 3000 cm ² / g in Blaine value, and more preferably finely powdered to exceed 3000 cm ² / g.

The amount of gypsum used is preferably 1 to 25 parts by weight, more preferably 5 to 20 parts by weight, and most preferably 7 to 15 parts by weight based on 100 parts by weight of cement. 1
When the amount is less than 25 parts by weight, the long-term strength development is small. When the amount exceeds 25 parts by weight, the initial setting is delayed, and the adhesion to the ground may be reduced.

Further, gypsum is preferably used in combination with calcium aluminate as a powder quick-setting agent described later, in order to further improve the long-term strength development. The amount of gypsum used in combination with calcium aluminate,
20 to 100 parts by weight of calcium aluminate
200 parts by weight is preferable, and 50 to 150 parts by weight is more preferable. If it is less than 20 parts by weight, the long-term strength development is small,
If it exceeds 200 parts by weight, the initial setting is delayed, and the adhesion to the ground may be reduced.

When cement concrete is mixed with a powder quick setting agent, the total amount of gypsum mixed with gypsum mixed with cement concrete and gypsum mixed with powdered quick setting agent is 100 parts by weight of cement. And 1
It is preferably from 25 to 25 parts by weight, more preferably from 5 to 20 parts by weight. If it is less than 1 part by weight, the strength developability is small, and if it exceeds 25 parts by weight, the cement concrete may expand and break.

The quick-setting agent slurry used in the present invention is a slurry containing a powdery quick-setting agent and water, and is a slurry obtained by mixing a powdery quick-setting agent and water.

[0013] The powdery quick setting agent is one which causes the setting of cement concrete at an early stage. As the powder quick-setting agent, calcium aluminate is preferred from the viewpoint of improving the initial setting and strength development.

The calcium aluminate used in the present invention is a mixture of a CaO raw material, an Al ₂ O ₃ raw material, and the like.
It is obtained by heat treatment such as firing in a kiln or melting in an electric furnace, and is a quick-setting component that causes the setting of cement concrete at an early stage. As a mineral component of calcium aluminate, CaO is C, Al ₂ O ₃
When A is used, a product obtained by pulverizing a heat-treated calcium aluminate represented by C ₃ A, C ₁₂ A ₇ , CA, and CA ₂ or the like may be mentioned, and one or more of these may be used in combination. . Further, as other mineral components, calcium aluminate in which alkali metals such as sodium, potassium and lithium are partially dissolved can be used. Among these, amorphous calcium aluminate obtained by quenching a heat-treated product corresponding to the C ₁₂ A ₇ composition is preferable in terms of reaction activity. Also, calcium aluminosilicate containing three components of CaO, Al ₂ O ₃ and SiO ₂ , and C ₁₁ A in which one CaO of C ₁₂ A ₇ is replaced by a halide such as CaF _2.
7. CaX ₂ (X is a halogen such as fluorine) and C
C ₄ A containing three components of aO, Al ₂ O ₃ , and SO _3
3. SO ₃ can be used similarly to calcium aluminate. Furthermore, alumina cement can be used as well. The particle size of the calcium aluminate, in terms of quick-setting property and the initial strength development, preferably 3000 cm ² / g or more in Blaine value, 4000 cm ² / g or more is more preferable. 300
If it is less than 0 cm ² / g, quick setting property and initial strength expression property may be reduced.

The amount of calcium aluminate used is preferably 2 to 20 parts by weight, more preferably 5 to 15 parts by weight, and most preferably 7 to 10 parts by weight based on 100 parts by weight of cement. If it is less than 2 parts by weight, it is difficult to promote the initial setting, and if it exceeds 20 parts by weight, the long-term strength development may be impaired.

It is preferable to use a gypsum and / or a setting accelerator in addition to calcium aluminate in addition to calcium aluminate in order to improve initial setting and strength development.

The setting accelerator used in the present invention refers to an agent which accelerates the setting of cement concrete. Examples of the setting accelerator include alkali metal aluminates, alkali metal carbonates, alkali metal hydroxides, slaked lime, And sulfates. The alkali metal aluminate promotes the initial setting of the cement. Examples of the alkali metal aluminate include lithium aluminate, sodium aluminate, and potassium aluminate, and one or more of these may be used in combination. Among them, sodium aluminate is preferred from the viewpoint of promoting initial setting.
The alkali metal carbonate promotes the initial setting and the initial strength of the cement. Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, and the like, and one or more of these may be used in combination. Among them, sodium carbonate is preferred in terms of initial strength development. When an alkali metal aluminate and an alkali metal carbonate are used in combination, initial coagulation is promoted, and the initial strength expression is further improved. The alkali metal hydroxide promotes the initial setting of the cement. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide, and one or more of these may be used in combination. Calcium hydroxide may be used from the viewpoint of promoting initial setting. Sulfates promote the initial setting of the cement. Examples of the sulfate include sulfates such as sodium sulfate, potassium sulfate, magnesium sulfate, and aluminum sulfate, and those excluding gypsum such as double salts such as alum, and one or more of these may be used in combination. You may. Among these, aluminum sulfate is preferred from the viewpoints of improving coagulation force and developing strength. Among the setting accelerators, alkali metal aluminates and / or alkali metal carbonates are preferable in terms of accelerating the initial setting.

The amount of the setting accelerator used is preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of calcium aluminate. If the amount is less than 0.5 part by weight, there is no effect. If the amount exceeds 20 parts by weight, the long-term strength development may be reduced.

The amount of use of these powdery quick setting agents is preferably 2 to 25 parts by weight with respect to 100 parts by weight of cement.
5-20 parts by weight are more preferred, and 7-15 parts by weight are most preferred. If it is less than 2 parts by weight, it is difficult to promote initial setting,
If it exceeds 25 parts by weight, the long-term strength development may be impaired.

The quick-setting agent slurry used in the present invention is a mixture of a powdery quick-setting agent and water, and is used by being mixed with cement concrete. The amount of water used in the quick-setting agent slurry is not particularly limited, but is preferably 5 to 300 parts by weight, more preferably 10 to 200 parts by weight, per 100 parts by weight of the powdery quick-setting agent. If the amount is less than 5 parts by weight, there is no effect of reducing the amount of dust, and if it exceeds 300 parts by weight, the amount of water with respect to the cement concrete increases, which may hinder the strength development.

The amount of the quick-setting agent slurry used is 10 cements.
The amount is preferably 2 to 25 parts by weight, more preferably 5 to 20 parts by weight, and most preferably 7 to 15 parts by weight based on 0 part by weight in terms of solid content. If it is less than 2 parts by weight, it is difficult to promote the initial setting, and if it exceeds 25 parts by weight, there is a possibility that long-term strength development may be impaired.

In the present invention, if necessary, one or more admixtures selected from the group consisting of a setting retarder, a water reducing agent, a thickener, a fibrous substance, and an ultrafine powder may be used. .

The setting retarder used in the present invention refers to an agent which retards the setting of cement. As a setting retarder,
Examples include organic acids, alkali carbonates, and phosphates. Examples of the organic acids include citric acid, tartaric acid, gluconic acid, malic acid, and lactic acid, and sodium salts and potassium salts thereof, and one or more of these may be used in combination. Among them, citric acid is preferred because it hardly inhibits the strength expression. Examples of the phosphate include monosodium phosphate, disodium phosphate, trisodium phosphate, sodium tripolyphosphate, sodium hexametaphosphate, sodium pyrophosphate, and sodium tetrapolyphosphate, and one or more of these. May be used in combination. Further, a potassium salt may be used instead of the sodium salt. Among these, sodium tripolyphosphate is preferred because it hardly inhibits the strength expression. Among the setting retarders, in terms of good strength development after delay,
Mixtures of organic acids and alkali carbonates are preferred. In this case, the mixing ratio of the organic acid and the alkali carbonate is preferably 10 to 700 parts by weight, more preferably 20 to 500 parts by weight, based on 100 parts by weight of the alkali carbonate.
If the amount is less than 10 parts by weight, there is no effect. If the amount is more than 700 parts by weight, curing is excessively delayed and curing may be poor.

The amount of the setting retarder to be used is preferably 0.01 to 5 parts by weight based on 100 parts by weight of cement, and is preferably 0.0 to 5 parts by weight.
5 to 3 parts by weight are more preferred. If the amount is less than 0.01 part by weight, it is difficult to suppress the setting of the cement, and if it exceeds 5 parts by weight, the strength development may be impaired.

The water reducing agent used in the present invention is a water reducing agent used for improving the fluidity of cement concrete and the dispersion stability of the quick-setting agent slurry, and may be any of a liquid or a powder. Examples of the water reducing agent include polyol derivatives, lignin sulfonic acid salts and derivatives thereof, and high-performance water reducing agents, and one or more of these may be used in combination. Among these, a high-performance water reducing agent is preferred in terms of high strength development and dispersion stability. The amount of the quick-setting agent, the amount of dust generated, and the rebound rate can be extremely reduced by the high-performance water reducing agent. Examples of the high-performance water reducing agent include a formalin condensate of an alkylallyl sulfonate, a formalin condensate of a naphthalene sulfonate, a formalin condensate of a melamine sulfonate, and a polycarboxylic acid polymer compound. Any of powdery materials can be used, and one or more of these may be used in combination. Among these, a formalin condensate of a naphthalene sulfonate, a formalin condensate of a melamine sulfonate, and a polycarboxylic acid-based polymer compound are preferable from the viewpoint of great effect.

The amount of the high-performance water reducing agent to be used is preferably 0.05 to 5 parts by weight, more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of cement in terms of solid content. If the amount is less than 0.05 part by weight, the effect is not obtained. If the amount exceeds 5 parts by weight, the strength development may be impaired.

The thickener used in the present invention is one that gives viscosity to cement concrete, prevents dripping immediately after spraying, reduces rebound rate, and suppresses dust generation. As the thickener, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, and celluloses such as hydroxyethylethylcellulose, alginic acid,
Polysaccharides such as sodium alginate, β-1,3 glucan, pullulan, guar gum, casein, and welan gum; vinyl acetate such as vinyl acetate, ethylene, vinyl chloride, methacrylic acid, acrylic acid, sodium acrylate, and unsaturated carboxylic acid. Copolymers and copolymers thereof, and emulsions such as those obtained by saponifying a vinyl acetate polymer or a copolymer thereof and modifying it to a polyvinyl alcohol skeleton, and the like, and one or more of these may be used in combination. Good. Among these, it is difficult to inhibit the initial setting,
Cellulose is preferred.

The amount of the thickener to be used is preferably 0.005 to 0.5 part by weight, preferably 0.1 to 0.5 part by weight, per 100 parts by weight of cement.
The amount is more preferably from 0.5 to 0.1 part by weight. If the amount is less than 0.005 parts by weight, the viscosity of the cement concrete is small, and dripping occurs when spraying, and the rebound rate increases. If the amount exceeds 0.5 parts by weight, the viscosity of the cement concrete increases, and the viscosity of the cement concrete increases. There is a possibility that the pumpability may be affected.

The fibrous substance used in the present invention has the effect of improving the impact resistance and elasticity of cement concrete.
Both inorganic and organic substances can be used. Examples of the inorganic fibrous substance include glass fiber, carbon fiber, rock wool, asbestos, ceramic fiber, and metal fiber, and examples of the organic fibrous substance include vinylon fiber, polyethylene fiber, polypropylene fiber, and polyacryl fiber. , Cellulose fibers, polyvinyl alcohol fibers, polyamide fibers, pulp, hemp, wood wool, and wood chips. Among these, metal fibers and vinylon fibers are preferable in terms of economy. The length of the fibrous material should be
50 mm or less is preferable, and 30 mm or less is more preferable. If it exceeds 50 mm, the pumping tube may be closed during the pumping.

The amount of the fibrous substance used is preferably 0.5 to 10 parts by weight, and more preferably 1 to 5 parts by weight based on 100 parts by weight of cement.
Parts by weight are more preferred. If the amount is less than 0.5 part by weight, there is no effect. If the amount exceeds 10 parts by weight, the strength development is impaired, and the effect may be lost.

The ultrafine powder used in the present invention has an average particle size of 1
0 μm or less, cement unit amount, dust amount,
And to reduce the rebound rate and improve the pumpability of cement concrete. Ultra fine powder includes fine slag, fine fly ash, bentonite, kaolin,
Fine calcium carbonate, silica fume and the like may be mentioned, and one or more of these may be used in combination. Among these, silica fume is preferable in terms of strength development.

The use amount of the ultrafine powder is preferably 1 to 50 parts by weight, more preferably 2 to 30 parts by weight, based on 100 parts by weight of cement. If the amount is less than 1 part by weight, there is no effect, and if it exceeds 50 parts by weight, the setting and the curing may be delayed.

The aggregate such as fine aggregate and coarse aggregate used in the present invention preferably has a low water absorption and a high aggregate strength, but is not particularly limited. The coarse aggregate includes river gravel, mountain gravel, lime gravel, and the like. Examples of the fine aggregate include river sand, mountain sand, lime sand, and silica sand.

The fine aggregate ratio is preferably 70% or more.
85% is more preferred. If it is less than 70%, the rebound rate and the amount of dust increase, and if it exceeds 85%, cement concrete adheres to the pumping pipe, and the pumpability may decrease. The maximum dimension of the aggregate is preferably 10 mm or less. 10
If it exceeds mm, the rebound rate may increase.

An AE agent or a foaming agent may be added to mix air bubbles to reduce the amount of dust.

The amount of water used in cement concrete is preferably 35 to 65 parts by weight, more preferably 40 to 55 parts by weight, based on 100 parts by weight of cement. If the amount is less than 35 parts by weight, the cement concrete cannot be sufficiently mixed. If the amount exceeds 65 parts by weight, strength development is low and the amount of the quick-setting agent slurry may be increased.

In the spraying method used in the present invention, cement concrete can be sprayed in view of required physical properties, economy and workability. As a spraying method, cement concrete and quick-setting agent slurry are separately pumped,
A spraying method of spraying a quick-setting sprayed cement concrete mixed and mixed is preferable, and a dry spraying method or a wet spraying method can be used. Among them, the wet spraying method is preferable because the amount of generated dust is small. As a dry spraying method, cement, gypsum, and aggregate are mixed and pneumatically fed.
There is a method in which two Y-shaped tubes are connected, water is added from one side, and then the quick-setting agent slurry is added in that order and sprayed in a wet state. As a wet spraying method, there is a method of mixing and kneading cement, gypsum, aggregate, and water, kneading the mixture, sending the mixture under air pressure, and adding a quick-setting agent slurry from one side of a Y-shaped pipe and spraying the mixture. No. As described above, by mixing the powdery quick-setting agent with the cement concrete as the quick-setting agent slurry, the amount of dust and the rebound rate can be reduced, and the working environment can be improved.

The preparation of the quick-setting agent slurry containing calcium aluminate exhibiting a quick-setting property should be carried out in such a manner that when the quick-setting agent slurry is left for a while after preparation, it is not hardened in the slurry for several minutes to tens of minutes. It is preferred to use a set retarder. However, when the curing is delayed for a long period of time, the quick-setting agent slurry is less likely to exhibit the original quick-setting effect, and the initial setting and the strength development of the quick-setting sprayed cement concrete may be reduced. Therefore, in order to sufficiently exhibit the quick-setting effect of the quick-setting agent slurry, it is preferable that the powdery quick-setting agent is mixed with cement concrete within 2 minutes after the quick-setting agent slurry is formed. More preferably, it is mixed with concrete. If it exceeds 2 minutes, the quick-setting force may be reduced.

For this purpose, it is preferred that the powdery quick-setting agent is made into a quick-setting agent slurry immediately before being mixed and mixed with cement concrete, and then this quick-setting agent slurry is mixed and mixed with cement concrete. As a method for preparing a quick-setting agent slurry by mixing and mixing a powdery quick-setting agent and water, a method in which a powdery quick-setting agent is pneumatically fed and water is added on the way, or a method in which a powdery quick-setting agent is added via a line mixer. A method in which a kneading agent and water are continuously kneaded and pumped is used. When the powdery quick-setting admixture and the water for slurrying the quick-setting admixture are mixed and mixed, the pressure for pumping the water is not particularly limited.
In addition, at the confluence of the powdery quick-setting agent and water, it is preferable to mix and mix the water in the form of a mist or a shower, since the mixing property of the quick-setting agent slurry is improved.

Among these, in that they are easily mixed with water,
A method of pumping a quick-setting agent slurry obtained by continuously kneading a powdery quick-setting agent and water via a line mixer is preferable. In this method, it is preferable that compressed air is blown in during the pumping of the quick-setting agent slurry, air-fed and mixed with the cement concrete. The position where the quick-setting agent slurry and the compressed air are mixed and mixed is 5 minutes from the converging point of the cement and concrete and the quick-setting agent slurry pneumatically fed.
m, and more preferably 0.1 to 2 m before. If it is less than 0.1 m, when the cement concrete enters the pipe on the quick binder slurry side due to fluctuations in the pumping pressure, etc., the discharge port of the compressed air will be closed. If it exceeds 5 m, the pumpability will be reduced and the pumping pipe will be blocked. There is a possibility that.

The admixture can be mixed on either the cement concrete side or the quick setting agent slurry side, and may be used on only one side or on both sides. However, it is possible to improve strength, prevent rebound and set control. In view of this, it is preferable to add it to the cement concrete side. However, the setting retarder is preferably mixed with the setting agent slurry when the setting time of the setting agent slurry must be extended. The setting accelerator is usually preferably mixed with the quick setting agent slurry. In addition, setting accelerator, setting retarder, thickener,
The ultrafine powder and the ultrafine powder may be independently added to the powdery quick setting agent side or the cement concrete side, or may be previously mixed with water mixed with the cement concrete or the powdery quick setting agent. There is no problem as long as the quick-setting sprayed concrete containing these materials is finally sprayed.

In the spraying method of the present invention, a conventional spraying equipment can be used. The spraying equipment is not particularly limited as long as spraying is sufficiently performed. For example, “Aliber 280” (trade name of Aliver Co., Ltd.) is used for pumping cement concrete, and is quickly set for pumping powdery quick-setting agent. An agent feeding device "Natom Cleat" or the like can be used. Examples of a pump for continuously kneading the powdery quick-setting admixture and water include “Ankomat Pump” (trade name, manufactured by Putzmeister Co., Ltd.). Usually, the pumping pressure of cement concrete is 2 to 10 kg /
cm ² is preferred. The pressure of the compressed air of the quick setting agent should be 0.1 to 3 kg / cm ² higher than the pressure of the cement concrete so that the inside of the pressing tube is not blocked when the cement concrete enters the pressing tube of the quick setting slurry. Is preferred. Further, the pumping speed of the quick-setting sprayed cement concrete is 4 to 20 m ³ / h. Further, at the junction of the quick-setting agent slurry and the cement concrete, the junction may have a pipe shape or a structure in which the inner wall of the pipe is likely to be in a turbulent state or a helical structure in order to improve the mixing property.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

Example 1 A unit amount of each material was 400 kg / m of cement.^Three, Water 20
0kg / m^Three, Fine aggregate 1406kg / m^Three, And coarse aggregate
357kg / m^ThreeAnd 100 parts by weight of cement
And mix 10 parts by weight of gypsum to make shotcrete
And feed speed 4m ^Three / H, pumping pressure 4kg / cm^Two Article
Under the circumstances, concrete pumping machine "Ariba-280"
did. On the other hand, this shotcrete
100 parts by weight of minate, 100 parts by weight of gypsum, and
100 parts by weight of calcium aluminate and gypsum
To the amount of water shown in Table 1
Was prepared. This adjusted quick-setting agent slurry is
To 100 parts by weight of solids
So that one of the Y-tubes provided on the way
Kneading continuously with the product name “Ankomat Pump”
Air by blowing compressed accelerator slurry
It was sent to give quick setting sprayed concrete. This quick-setting spray
The concrete was evaluated. Table 1 shows the results. What
Note that in the comparative example, a quick-setting additive
Spraying the powdery quick setting agent without using slurry
Mixed with the plate. (Materials used) Cement a: ordinary Portland cement, commercial product, blur
3200cm^Two/ G, specific gravity 3.16 Cement b: early strength Portland cement, commercial product, blur
Value 4000cm^Two/ G, specific gravity 3.14 Fine aggregate: river sand from Himekawa, Niigata, surface water rate 4.0%, specific gravity
2.61 coarse aggregate: gravel from Himekawa river, Niigata prefecture, surface dry condition, specific gravity 2.6
5. Maximum dimension 10mm Gypsum I: Anhydrous gypsum ground product, Blaine value 5800
cm^Two/ G calcium aluminate A: main component C₁₂A₇, Amorphous,
Brain value 6000cm ^Two/ G (Measurement method) Dust amount: 4 m for quick setting sprayed concrete^Three/ H pumping speed
3.5 minutes high in the shape of an arch made of iron plate for 30 minutes
m, a 2.5 m wide simulated tunnel. Every 10 minutes
The amount of dust was measured at a fixed position of 3 m from the spray location and obtained.
The average of the measured values is shown.

[0045]

[Table 1]

Example 2 Cement a 400 kg / m^Three, Water 200kg / m^Three, Thin
Aggregate 1406kg / m ^Three, And 357 kg / m of coarse aggregate^Three
Gypsum per 100 parts by weight of cement a
Mix parts by weight to make shotcrete, pumping speed 4m
^Three / H, pumping pressure 4kg / cm^Two Under the conditions of
Pneumatic pumping was carried out using a heat pump "Ariba-280".
On the other hand, the amount shown in Table 2 is based on 100 parts by weight of cement a.
Powder quick-setting agent 100 made of calcium aluminate
Put water to 50 parts by weight with respect to parts by weight.
Continuous kneading with Star brand name "Ankomat Pump"
Thus, a quick setting slurry was prepared. This quick setting slurry
Pump and then the quick-setting slurry and spray concrete.
At a position 1m before the confluence of the plate, the pumping pressure is 5kg / c
m^Two Of the quick-setting binder slurry by blowing compressed air
did. Then, a Y-tube is provided in the middle, and from one side of the Y-tube.
The quick-setting agent slurry is prepared by mixing powdery quick-setting agent and water.
Combine with sprayed concrete within 15 seconds after slurrying
The mixture was flow-mixed to give quick-setting sprayed concrete. This quick setting
The shotcrete was evaluated. The results are shown in Table 2.
You. (Materials used) Calcium aluminate B: sodium aluminosilicate
System, commercial product, Brain value 5900cm^Two/ G (Measurement method) Compressive strength: Spray the prepared quick-setting concrete
Was. 1 hour old 25cm wide x 25cm long pull-out
Using the formwork specimen, remove the pin from the surface of the pullout formwork.
Cover with quick-setting sprayed concrete, and pin from the back of the formwork
And determine the pull-out strength at that time.
Degree) = (Pull-out strength) × 4 / (Specimen contact area)
The compression strength was calculated from. 50cm width after 1 day
Diameter 5 collected from a mold 50 cm long x 20 cm thick
Measure a test specimen of cm × 10cm length with a 20-ton pressure machine
Then, the compressive strength was determined.

[0047]

[Table 2]

Example 3 A powdery quick setting agent consisting of 100 parts by weight of calcium aluminate A and the amount of gypsum shown in Table 3 was mixed with cement a100
The procedure was performed in the same manner as in Example 2 except that a quick-setting agent slurry was prepared so as to be 10 parts by weight to obtain a quick-setting sprayable concrete. Table 3 shows the results. (Materials used) Gypsum II: Ground water gypsum, 350 Blaine value
0 cm ² / g

[0049]

[Table 3]

Example 4 To 100 parts by weight of cement a was used as gypsum in the amount shown in Table 4 to make a shotcrete, and a powder quick-setting agent consisting of 100 parts by weight of calcium aluminate A and 100 parts by weight of gypsum I was added to the cement. Example 2 was carried out in the same manner as in Example 2 except that a quick-setting binder slurry was prepared so as to be 10 parts by weight with respect to 100 parts by weight of a to obtain quick-setting sprayable concrete. Table 4 shows the results.

[0051]

[Table 4]

Example 5 100 parts by weight of calcium aluminate A and gypsum I1
100 parts by weight of a powdery quick-setting admixture was added to cement a100
A quick-setting agent slurry is prepared so as to be 10 parts by weight with respect to a part by weight, and the mixing position where the quick-setting agent slurry and the compressed air meet is mixed with the quick-setting agent slurry sent by air and the sprayed concrete. The procedure was performed in the same manner as in Example 2 except that the point was set to a position at a distance before shown in Table 5 from the point. Table 5 shows the results. (Measurement method) Pumpability: Quick-setting sprayed concrete was sprayed at a pumping speed of 4 m ³ / h and a pumping pressure of 4 kg / cm ² for 30 minutes using a pumping tube, and the pressure in the pumping tube was measured. In the case where the pressure in the pressure feeding pipe is 4.0 to 5.5 kg / cm ² , even when the pressure in the pressure feeding pipe becomes 6.0 kg / cm ² or more, the pressure in the pressure feeding pipe is increased. 0-5.5
The case where the pressure / pressure was reduced to 4.0 kg / cm ² and the case where the pressure / pressure did not reach 4.0 to 5.5 kg / cm ² even when an impact was applied to the pressure / feed tube was rated as x.

[0053]

[Table 5]

Example 6 100 parts by weight of calcium aluminate A and gypsum I1
100 parts by weight of a powdery quick-setting admixture was added to cement a100
The amount of water used in the slurry is 10 parts by weight based on parts by weight, and the amount of water used in the binder is 100 parts by weight of the powder quick-setting agent so that the amount is as shown in Table 6. The same operation as in Example 2 was carried out except that the slurry was prepared to give quick-setting sprayed concrete. Table 6 shows the results.

[0055]

[Table 6]

Example 7 100 parts by weight of calcium aluminate A and gypsum I1
100 parts by weight of a powdery quick-setting admixture was added to cement a100
The procedure was performed in the same manner as in Example 2 except that a quick-setting agent slurry was prepared so as to have the amount shown in Table 7 with respect to parts by weight to obtain a quick-setting sprayable concrete. Table 7 shows the results.

[0057]

[Table 7]

Example 8 100 parts by weight of calcium aluminate A, gypsum I1
100 parts by weight and a powdery quick-setting admixture comprising the setting accelerator in the amount shown in Table 8 were added to 100 parts by weight of cement a to 10 parts by weight.
The procedure was performed in the same manner as in Example 2 except that a quick-setting agent slurry was prepared so as to be in parts by weight to obtain a quick-setting sprayable concrete. Table 8 shows the results. (Materials used) Setting accelerator: Commercial sodium aluminate Setting accelerator: Commercial aluminum sulfate Setting accelerator: Commercial sodium carbonate Setting accelerator: Commercial sodium hydroxide Setting accelerator: Commercial hydrated lime

[0059]

[Table 8]

Example 9 A powder consisting of 100 parts by weight of calcium aluminate A and 100 parts by weight of gypsum I was mixed with 100 parts by weight of cement a and 10 parts by weight of gypsum and the setting retarder in the amount shown in Table 9 to give a shotcrete. The same procedure as in Example 2 was carried out except that a quick-setting agent slurry was prepared so that the quick-setting agent was 10 parts by weight with respect to 100 parts by weight of the cement a to obtain quick-setting sprayable concrete. Table 9 shows the results. (Materials used) Setting retarder: 1 by weight ratio of citric acid and potassium carbonate
Mixture of 1 Setting retarder: Commercial citric acid Setting retarder: Commercial sodium tripolyphosphate

[0061]

[Table 9]

Example 10 100 parts by weight of cement a and 10 parts by weight of gypsum and a water reducing agent in the amount shown in Table 10 were mixed to give a shotcrete, and a powdery mixture consisting of 100 parts by weight of calcium aluminate A and 100 parts by weight of gypsum I Quick setting agent, cement a
The procedure was performed in the same manner as in Example 2 except that a quick-setting agent slurry was prepared so as to be 10 parts by weight with respect to 100 parts by weight to obtain a quick-setting sprayable concrete. Table 10 shows the results. (Materials used) Water reducing agent a: Commercially available polycarboxylic acid polymer compound Water reducing agent a: Commercially available naphthalene sulfonate type formalin condensate (Measurement method) Slump: According to JIS A1101.

[0063]

[Table 10]

Example 11 100 parts by weight of cement a and 10 parts by weight of gypsum and a thickener in an amount shown in Table 11 were mixed to give shotcrete, and a powder consisting of 100 parts by weight of calcium aluminate A and 100 parts by weight of gypsum I A quick setting agent, cement a
The procedure was performed in the same manner as in Example 2 except that a quick-setting agent slurry was prepared so as to be 10 parts by weight with respect to 100 parts by weight to obtain a quick-setting sprayable concrete. Table 11 shows the results. (Materials used) Thickener i: Methylcellulose Thickener ii: Hydroxypropylmethylcellulose (Measurement method) Drip: Rapid setting sprayed concrete at a pumping speed of 4 m ³ / h for 1 minute, height 3.5 m, width 2. It was sprayed on the 5m mock tunnel, and was evaluated as ◎ if there was no dripping immediately after spraying, ○ if a little dripping was observed, and × if dripping was considerable.

[0065]

[Table 11]

Example 12 100 parts by weight of cement a and 10 parts by weight of gypsum and a fibrous substance in an amount shown in Table 12 were mixed to give a shotcrete, and a powder consisting of 100 parts by weight of calcium aluminate A and 100 parts by weight of gypsum I The same procedure as in Example 2 was carried out except that a quick-setting agent slurry was prepared so that the quick-setting agent was 10 parts by weight with respect to 100 parts by weight of the cement a to obtain quick-setting sprayable concrete. Table 12 shows the results. (Materials used) Fibrous substance a: Vinylon fiber, fiber length 10 mm Fibrous substance b: Steel fiber, fiber length 30 mm (Evaluation method) Impact resistance: Shotcrete after 1 hour of material age is width 20
cm, length 20cm, thickness 1cm into the mold,
The bottom was removed, placed on flat sand, and a sphere weighing 100 g was dropped from a height of 50 cm. If the number of falls is less than 5 times and cracked and destroyed, ×; cracked but not broken ○; if not cracked ◎
And

[0067]

[Table 12]

Example 13 A mixture of 10 parts by weight of gypsum and 100 parts by weight of ultrafine powder shown in Table 13 was mixed with 100 parts by weight of cement a to give a shotcrete, and a powder consisting of 100 parts by weight of calcium aluminate A and 100 parts by weight of gypsum I Quick setting agent, cement a
The procedure was performed in the same manner as in Example 2 except that a quick-setting agent slurry was prepared so as to be 10 parts by weight with respect to 100 parts by weight to obtain a quick-setting sprayable concrete. Table 13 shows the results. (Materials used) Ultrafine powder α: Commercial silica fume, average particle size 10 μm or less Ultrafine powder β: Commercial metakaolin, average particle size 10 μm or less (Measurement method) Rebound rate: Rapid-setting sprayed concrete at a pumping speed of 4 m ³ / h. It was sprayed on a simulated tunnel 3.5 m high and 2.5 m wide for a minute. After spraying, measure the amount of quick-setting spray concrete that fell without adhering, and (rebound rate) = (weight of quick-setting spray concrete that did not adhere to the simulated tunnel during spraying) / Calculated from the formula of (weight of quick-setting spray concrete used for spraying) × 100 (%).

[0069]

[Table 13]

Example 14 The amount of cement and water was kept constant, the amount of fine aggregate as shown in Table 14 was used as shotcrete, and a powder quick-setting agent consisting of 100 parts by weight of calcium aluminate A and 100 parts by weight of gypsum I was used. For 100 parts by weight of cement a, 10
The procedure was performed in the same manner as in Example 2 except that a quick-setting agent slurry was prepared so as to be in parts by weight to obtain a quick-setting sprayable concrete. Table 14 shows the results.

[0071]

[Table 14]

Example 15 Shotcrete was prepared using the coarse aggregate having the maximum size shown in Table 15 and a powder quick-setting agent consisting of 100 parts by weight of calcium aluminate A and 100 parts by weight of gypsum I was added to 100 parts by weight of cement a. Example 2 was carried out in the same manner as in Example 2 except that a quick-setting agent slurry was prepared so as to be 10 parts by weight to obtain a quick-setting sprayable concrete. Table 15 shows the results.

[0073]

[Table 15]

Example 16 The procedure was carried out except that the time from mixing the powdery quick-setting agent and water to form the quick-setting agent slurry until the quick-setting agent slurry was combined with the sprayed concrete was set to the time shown in Table 16. The procedure was as in Example 2. In addition, the time until the merging and mixing was changed by changing the length of the pressure feeding tube until the quick-setting agent slurry was mixed with the compressed air. Table 16 shows the results.

[0075]

[Table 16]

Example 17 Cement a 400 kg / m ³ , fine aggregate ratio 80%, and
The amount of water was as shown in Table 17 with respect to 100 parts by weight of cement a, and 10 parts by weight of gypsum and 1.0 part by weight of a water reducing agent were mixed with 100 parts by weight of cement to form sprayed concrete, and calcium was added. A powder quick setting agent consisting of 100 parts by weight of aluminate A and 100 parts by weight of gypsum I, and a quick setting agent slurry was prepared so as to be 10 parts by weight with respect to 100 parts by weight of cement a to obtain quick setting sprayable concrete. Other than that, it carried out similarly to Example 2. Table 17 shows the results.
Shown in

[0077]

[Table 17]

Example 18 Thickener i was mixed with water used for the quick-setting agent slurry in an amount of 0.05 part by weight with respect to 100 parts by weight of cement a, and 100 parts by weight of calcium aluminate A and gypsum I100 A powdery quick setting agent consisting of parts by weight was added to cement a1.
The procedure was performed in the same manner as in Example 2 except that a quick-setting agent slurry was prepared so as to be 10 parts by weight with respect to 00 parts by weight to obtain a quick-setting sprayable concrete. As a result, the amount of dust is 0.
It was 2 mg / m ³ .

Example 19 A water reducing agent (a) was mixed with 100 parts by weight of cement a to 1.0 part by weight in terms of solid content, and 100 parts by weight of calcium aluminate A was mixed with water used for the quick-setting agent slurry. Example 2 except that a powdery quick setting agent consisting of 100 parts by weight of gypsum and gypsum I was used to prepare a quick setting agent slurry so as to be 10 parts by weight with respect to 100 parts by weight of cement a to obtain a quick setting sprayable concrete. The same was done. As a result, 1
The time intensity is 2.5 N / mm ² , and the three-hour intensity is 3.6 N /
mm ² , 1-day strength is 15.7 N / mm ² , 7-day strength is 2
8.8 N / mm ² and 28-day strength of 48.0 N / mm
^{Was 2} .

Example 20 Ultrafine powder α was mixed with water used for the quick-setting agent slurry in an amount of 10 parts by weight based on 100 parts by weight of cement a.
100 parts by weight of calcium aluminate A and gypsum I1
100 parts by weight of a powdery quick-setting admixture was added to cement a100
The procedure was performed in the same manner as in Example 2 except that a quick-setting binder slurry was prepared so as to be 10 parts by weight with respect to parts by weight to obtain a quick-setting sprayable concrete. As a result, the rebound rate was 8.4%.

[0081]

According to the spraying method of the present invention, the amount of dust can be reduced as compared with the case where the powdery quick setting agent is mixed with cement concrete. Also, in the early and long term,
Since high strength development can be expected, spraying thickness can be reduced, construction cost can be reduced, and safety can be improved because high strength can be obtained immediately after spraying. Furthermore, by adding water during the pneumatic feeding of the powder quick-setting agent, or by continuously mixing the powder quick-setting agent and water to form a quick-setting material slurry, Since it mixes with cement concrete within 2 minutes after contact with water, quick-setting sprayable cement concrete can be sprayed without impairing the properties of the quick-setting agent. In the blowing, even if only the quick-setting admixture is pumped without cement concrete being pumped, the amount of dust is small, so that dust generation during construction can be suppressed.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 22:14 20:00) 103: 12 (72) Inventor Masahiro Iwasaki 2209 Aomi, Omi-cho, Nishikubiki-gun, Niigata Denki Kagaku Kogyo Co., Ltd. (72) Inventor Akira Watanabe 2209 Aomi, Aomi-cho, Nishikubiki-gun, Niigata Prefecture Inside the Aomi Plant of Denki Kagaku Kogyo Co., Ltd. Inside

Claims (8)

[Claims] 1. A spray material comprising a mixture of cement concrete containing cement and gypsum, and a quick-setting agent slurry containing a powdery quick-setting agent. 2. The spray material according to claim 1, further comprising a setting accelerator. 3. A setting retarder, a water reducing agent, a thickener,
The spraying material according to claim 1, comprising one or more admixtures selected from the group consisting of a fibrous substance and an ultrafine powder. 4. The fine aggregate ratio of cement concrete is 70.
% Or more. 5. The spray material according to claim 1, wherein the maximum size of the coarse aggregate is 10 mm or less. 6. A method in which a quick-setting agent slurry is pneumatically fed by compressed air at a position before a converging point where the cementing concrete is merged with the cement concrete, and then the air-pressed quick-setting agent slurry and the cement concrete are merged and mixed. The method for spraying a spray material according to any one of claims 1 to 5, characterized in that: 7. The spraying method according to claim 6, wherein the quick-setting agent slurry and the compressed air are mixed within 5 m from the junction of the cement concrete and the quick-setting agent slurry fed by air. 8. The quick-setting agent slurry and cement concrete are mixed within 2 minutes after mixing the powdery quick-setting agent and water to form a quick-setting agent slurry.
Or the spraying method according to 7.