JP2000297600A - Concrete spraying method and spraying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concrete spraying method and a spraying device spraying concrete evenly to the natural ground and lowering a dropping amount of concrete due to a rebound. SOLUTION: Concrete is conveyed to a piston pump 1 junction pipe 3, and then, compressed air is supplied to a branch pipe for the junction pipe 3 so as to pneumatically convey concrete to a junction pipe 6, while a pneumatically conveyed quick binder is supplied to a branch pipe for the junction pipe 6 so as to be mixed with the concrete, and then, the concrete is sprayed from a spraying nozzle 9. In this method, a pressure of the compressed air fed to the branch pipe for the junction pipe 3 is adjusted to 3-6 kg/cm2, while a total amount of the compressed air fed to the junction pipe 3 and to the junction pipe 6 is adjusted to 8-15 m3/minute on an atmospheric pressure conversion basis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of spraying concrete for, for example, reinforcing a ground and stabilizing an excavated surface in tunnel excavation work, and a spraying apparatus used for the method.

[0002]

2. Description of the Related Art Conventionally, as a method of spraying concrete, compressed air sent from a compressor is supplied into a transport pipe for transporting concrete sent by a piston pump or the like, and concrete is pneumatically transported. After mixing concrete and quick-setting material, a method of spraying concrete from a spray nozzle is common.

[0003]

However, in the above-mentioned conventional method, the amount of air used for spraying is not sufficiently considered, and the method is usually carried out using the maximum amount of air obtained by a compressor. ing. The method of using the maximum amount of air in this way is effective for spraying concrete without clogging in the transport pipe, but the amount of compressed air used tends to be excessive, and the concrete transport speed However, when the concrete blown out from the spray nozzle collides with the ground due to the spraying, the amount of concrete falling due to rebound increases, and the spraying efficiency is significantly reduced.

[0004] In recent years, a method has been adopted in which steel fibers are added to concrete to increase the strength of the sprayed concrete by the strength of the steel fibers, thereby reducing the total amount of the sprayed concrete. In this case, during the pneumatic transportation of the steel fiber concrete in the transport pipe, the effect of the difference in specific gravity, particle size, and shape of the steel fiber and the concrete, mortar component and aggregate components such as sand and gravel in the concrete or concrete are affected. Due to the separation, the quick-setting material does not act uniformly on the entire material, and as a result, among the concrete sprayed on the ground, especially the steel fibers with a large specific gravity and a large difference in shape fall a lot due to rebound As a result, there is a problem that the composition of the original steel fiber concrete and the composition of the steel fiber concrete after spraying are greatly different. Furthermore, since such a steel fiber is expensive, there is a problem that the construction cost is large.

The main object of the present invention is to reduce the amount of falling of the sprayed concrete due to rebound, and in the case of steel fiber concrete, to reduce the amount of steel fiber falling in view of such conventional problems. It is assumed that.

[0006]

The method for spraying concrete according to the present invention, which has been accomplished to achieve the above object, will be described with reference to FIG.
Is transported to the junction pipe 3 via the transport pipe 2 by the
Compressed air sent from the compressor 4 is supplied to the branch pipe, and the concrete is pneumatically transported to the junction pipe 6 via the transport pipe 5, and pneumatically transported to the branch pipe of the junction pipe 6 from the quick-set material supply equipment 7. After supplying the quick setting material and mixing the concrete and the quick setting material, the quick setting material is transported through the transport pipe 8 and sprayed.
In the method of spraying more concrete on the spray surface, the pressure of the compressed air supplied to the branch pipe of the junction pipe 3 is 3 to
It is characterized in that it is adjusted to be within the range of 6 kg / cm ² .

Further, in the concrete spraying apparatus of the present invention, concrete is transported by a piston pump 1 to a transport pipe 2.
And the compressed air sent from the compressor 4 is supplied to the branch pipe of the merge pipe 3 to pneumatically transport the concrete to the merge pipe 6 via the transport pipe 5.
After supplying the quick-setting material pneumatically transported from the quick-setting material supply equipment 7 to the branch pipe of the merging pipe 6 to mix the concrete and the quick-setting material, the concrete is rapidly transported through the transport pipe 8 and sprayed from the spray nozzle 9. A compressed air transport pipe 1 that connects a compressor 4 and a branch pipe of a junction pipe 3
Between 0, a flow meter 11 for compressed air, a valve 12 for adjusting the flow rate thereof, and a pressure gauge 13 provided between the valve 12 and a branch pipe of the merging pipe 3 are provided. . The valve 12 is adjusted so that the pressure indicated by the pressure gauge 13 is in the range of 3 to 6 kg / cm ² during operation of the apparatus.

In the present invention, the total amount of compressed air supplied to the merge pipe 3 and the merge pipe 6 is 8 to 15 m in terms of atmospheric pressure.
It is preferable to adjust so as to be within the range of ³ / min,
Further, it is preferable to use the transport pipe 5 having an inner diameter of 55 to 105 mm and a length of 7 m or less, and to use the transport pipe 8 having an inner diameter of 55 to 105 mm and a length of 3 m or less.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an example of the configuration of a concrete spraying apparatus according to the present invention.

As shown in FIG. 1, concrete for spraying (or steel fiber concrete) is kneaded and mixed by a commercially available mixer, supplied to a piston pump 1, and transported in a transport pipe 2 by the piston pump 1. , To the junction pipe 3. That is, only the concrete is sent into the transport pipe 2.

The air compressed by the compressor 4 is sent to the confluence pipe 3 via the compressed air transport pipe 10 and merges with the concrete. Here, a flow meter 11 for measuring the amount of air, a valve 12 for adjusting the increase / decrease thereof, and a valve 12
A pressure gauge 13 for measuring the pressure of the compressed air is provided between the pressure gauge and the junction pipe 3.

The concrete to which the compressed air is supplied in the merging pipe 3 is sent to the merging pipe 6 while speeding up and dispersing in the transport pipe 5 by the expansion and flow of the compressed air.

The quick-set material is sent to the junction pipe 6 by the quick-set material supply device 7 through the quick-set material transport pipe 14. Compressed air is supplied from the compressor 4 to the quick-setting material supply device 7, and the quick-setting material is pneumatically transported by the compressed air. Therefore, compressed air is also sent into the quick-set material transport pipe 14 together with the quick-set material. The amount of compressed air sent to the quick-set material supply device 7 is measured by a flow meter 16 provided in the middle of a compressed air transport pipe 15 connecting the compressor 4 and the quick-set material supply device 7, and the amount is measured by a valve 17. Will be adjusted.

In the joining pipe 6, the pneumatically transported concrete and the pneumatically transported quick-setting material are combined, and the quick-setting material is added to the concrete.

The concrete to which the quick-setting material has been added is transported in the transport pipe 8 while being mixed with the quick-setting material by the expansion and flow of the compressed air, and discharged from the spray nozzle 9.
It is sprayed on the ground, which is the spraying surface.

In the concrete spraying method of the present invention, the pressure of the compressed air supplied to the branch pipe of the junction pipe 3 is 3 to 6 kg / cm ² , more preferably 4 to 5 kg / cm.
It is adjusted to be within the range of ² . The adjustment of the pressure of the compressed air is performed such that the pressure indicated by the pressure gauge 13 is within the above range in the apparatus shown in FIG.

Since the pressure gauge 13 is located in the middle of the compressed air transport pipe 10 and is further provided between the valve 12 for adjusting the increase and decrease of the compressed air amount and the branch pipe of the junction pipe 3,
The indicated value of the pressure gauge 13 indicates the pressure of the compressed air supplied to the branch pipe of the junction pipe 3 and indicates the state of transport of the concrete from the junction pipe 3 to the spray nozzle 9. That is, when the amount of the compressed air is small and the transport speed of the concrete is low, that is, when the concrete is closed in the pipe, the indicated value of the pressure gauge 13 becomes high. Conversely, when the amount of compressed air is large and the transport speed of the concrete is high, that is, when the concrete is flowing easily in the pipe, the indicated value of the pressure gauge 13 becomes low.

Therefore, when the opening degree of the valve 12 is reduced and the amount of compressed air is reduced, the transport speed of concrete is reduced, and the indicated value of the pressure gauge 13 is increased. At this time, if the indicated value of the pressure gauge 13 is higher than 6 kg / cm ² , the transport speed of the concrete is too slow, and the concrete is hardly sufficiently dispersed in the compressed air, and the concrete is intermittently solidified from the spray nozzle 9. And it is easy to be discharged. In such a state, the spraying speed of the concrete is too slow, so that the concrete cannot be sprayed smoothly on the ground and the thickness of the sprayed concrete cannot be kept uniform. Also,
Since the transport speed near the pipe wall of the transport pipe decreases, the paste component attached to the pipe wall falls without reaching the ground. If the opening of the valve 12 is further reduced, the concrete blocks in the transport pipe or the merge pipe.

On the other hand, when the opening degree of the valve 12 is increased and the amount of compressed air is increased, the transport speed of concrete is increased and the indicated value of the pressure gauge 13 is reduced. At this time, if the indicated value of the pressure gauge 13 is lower than 3 kg / cm ² , the transport speed of the concrete is too fast, and the speed at which the concrete discharged from the spray nozzle 9 collides with the ground is too fast, and the concrete drops due to rebound. The amount increases sharply. Further, in the case of steel fiber concrete, the steel fiber is separated from the cement component in the transport pipe, and does not adhere to the concrete even by the addition of the quick setting material, and falls to increase the amount of rebound.

Therefore, as in the present invention, the pressure of the compressed air supplied to the branch pipe of the merging pipe 3, that is, the pressure indicated by the pressure gauge 13 is adjusted to be in the range of 3 to 6 kg / cm ^2. As a result, the concrete transport speed can be maintained within an appropriate range, the concrete can be sufficiently dispersed in the compressed air to be sprayed smoothly on the ground, and the drop amount due to rebound is suppressed to a low level. Can be.

Further, in the present invention, the total amount of compressed air supplied to the merging pipe 3 and the merging pipe 6 is 8 to 8 in terms of atmospheric pressure.
It is preferable to adjust so as to be within a range of 15 m ³ / min, and more preferably to adjust within a range of 8 to 13.5 m ³ / min.

When the concrete has fluidity suitable for spraying (slump value is about 8 to 15 cm), the pressure of the compressed air supplied to the branch pipe of the merging pipe 3 is 3 to
By adjusting so as to be within the range of 6 kg / cm ² , the above-mentioned effects can be sufficiently exerted.

However, if the fluidity of the concrete is too good, the pressure of the compressed air supplied to the branch pipe of the merging pipe 3 decreases, and if the pressure is adjusted to a low value close to 3 kg / cm ² at this time, The amount of compressed air may be too high and the concrete transport speed may exceed a reasonable range. On the other hand, when the concrete is too hard, the pressure of the compressed air supplied to the branch pipe of the junction pipe 3 increases, and at this time, the pressure of 6 kg
When adjusted to a high value close to / cm ² , the amount of compressed air may be too small and the transport speed of concrete may fall below an appropriate range.

Even in such a case, the total amount of compressed air supplied to the merging pipe 3 and the merging pipe 6 should be 8 to 8 in terms of atmospheric pressure.
By adjusting the flow rate within the range of 15 m ³ / min, it is possible to maintain the transport speed of the concrete within an appropriate range, and the above-mentioned effects can be sufficiently obtained even for concrete having a wider range of fluidity. Can be demonstrated. That is, when a relatively soft concrete having a high fluidity (for example, a slump value of 18 cm or more) is used, the total amount of compressed air is adjusted to a low value close to 8 m ³ / min in terms of atmospheric pressure, and By inducing the pressure of the compressed air supplied to the branch pipe to a high value close to 6 kg / cm ² ,
Concrete transportation speed can be reduced to an appropriate range. Conversely, when using relatively hard concrete having a low fluidity (for example, a slump value of less than 8 cm), the total amount of compressed air is adjusted to a high value close to 15 m ³ / min. Transport speed can be increased to an appropriate range.

In the present invention, the transport pipe 5 has an inner diameter of 55 to 105 mm and a length of 7 m or less, and the transport pipe 8 has an inner diameter of 55 to 105 mm.
It is preferable to use one having a length of 3 m or less. If the inner diameter and the length of the transport pipe 5 and the transport pipe 8 are out of this range, the pressure of the compressed air supplied to the branch pipe of the merge pipe 3 and the total amount of the compressed air are adjusted to the appropriate ranges described above. Becomes difficult.

Specifically, if the inner diameters of the transport pipe 5 and the transport pipe 8 are smaller than 55 mm, the transport resistance of the concrete is too large, and if concrete having low fluidity is used, the transport pipe may be blocked in the transport pipe. Only relatively soft, highly fluid concrete can be used. Conversely, if the inner diameters of the transport pipes 5 and 8 are larger than 105 mm, the volume ratio of air in the transport pipes increases, the loss of quick-setting material increases, and a large amount of compressed air is required. It is necessary to increase the size, which increases the cost of the apparatus.

When the length of the transport pipe 5 exceeds 7 m,
The transport resistance of the concrete increases, and in particular, when low-flow concrete is used, it may be blocked in the transport pipe, and only relatively soft high-flow concrete can be used. When the length of the transport pipe 8 exceeds 3 m, the transport resistance of the concrete increases, and the time required for the concrete to be discharged from the spray nozzle 9 increases. The concrete is easily clogged.

The transport pipe 5 and the transport pipe 8 as shown in FIG. 1 are not essential, and the merging pipe 3, the merging pipe 6 and the spray nozzle 9 can be directly connected. In this case, the “transportation pipe 5” and “transportation pipe 8” referred to in the specification of the present application refer to the portion from the junction of the junction pipe 3 to the junction of the junction pipe 6 and the junction of the junction pipe 6 respectively. Spray nozzle 9
Up to the point.

[0030] As described above, the present invention provides a transport pipe for transporting concrete sent by a piston pump.
In a method in which compressed air for transporting concrete and compressed air for supplying a quick-setting material are supplied in two stages and the concrete is blown from a spray nozzle, the compressed air has not been sufficiently considered. By stipulating the pressure, the total amount of compressed air, the pipe diameter, and the pipe length, the concrete can be sprayed satisfactorily, and it is now possible to cope with concrete with a wider range of fluidity. .

As the piston pump 1 used in the present invention, a commercially available piston pump can be used. As a typical example, the concrete discharge capacity is about 25 m ³ / h at the maximum, and the concrete discharge amount can be adjusted by the piston speed. Things are used.

The spray nozzle 9 is generally a tapered tube whose diameter is reduced as it goes toward the outlet, and the taper angle may be about 0.5 degrees. The diameter of the outlet of the spray nozzle 9 is preferably about 50 mm.

The quick-setting material supply device 7 can use a device that dehumidifies the compressed air supplied from the compressor 4 with an attached air dryer or aftercooler, and pneumatically transports the quick-setting material using the dehumidified compressed air. The amount of compressed air used for supplying the quick-setting material is preferably approximately 3 to 5 m ³ / min in terms of atmospheric pressure. This air volume is
In the apparatus of FIG. 1, the flow rate is measured by the flow meter 16 on the compressed air supply side. In addition, as the quick-set material transport pipe 14,
For example, a hose having a diameter of 3 / 4B or 1B can be used.

The amount of the quick setting material is preferably not more than 10% by weight based on the amount of cement in concrete. Examples of such quick-setting materials include those which are already known in the form of a powder and include, for example, calcium aluminates and aluminum salts (such as sodium aluminate and aluminum sulfate) and carbonate as main components, and mixtures thereof. And the like. As the flow meter 11 and the flow meter 16, commercially available ones can be used, and it is preferable that the indicated value is not affected by the drain contained in the compressed air.

[0035]

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

(Examples 1 to 3 and Comparative Examples 1 and 2) A concrete spraying apparatus shown in FIG. 1 was assembled. The inner diameters of the transport pipes 5 and 8 are 65 mm, and the transport pipe 2 is 1 mm.
5 m, the transport pipe 5 was 3 m, and the transport pipe 8 was 1 m. Also,
The spray nozzle 9 has an inlet diameter of 65 mm to an outlet diameter of 50 m.
m was used.

For the concrete used for spraying, the unit amount of each material was 450 kg / m ³ of cement and 203 kg of water.
/ M ³ , fine aggregate 1187 kg / m ³ , coarse aggregate 512 kg
/ M ³ and the steel fibers 78.5Kg / m ^3, was further assumed that the water-reducing agent were added 0.8 parts by weight to 100 parts by weight of cement. The slump value of this concrete is 18c
m. The quick-setting material is cement 100 in concrete.
8 parts by weight were used per part by weight. Details of the materials used are shown below.

[Materials Used] Cement: Ordinary Portland cement (Brain value: 32)
00 cm ² / g, specific gravity 3.16) Fine aggregate: river sand from Himekawa, Niigata (Surface water rate 4.0%, specific gravity 2.61) Coarse aggregate: gravel from Himekawa, Niigata (surface dry, specific gravity 2) .6
5, Maximum dimension 10mm) Quick setting material: Calcium aluminate quick setting material, commercial product Water reducing agent: Polycarboxylic acid-based high-performance water reducing agent, commercial product Steel fiber: Commercial product (specific gravity 7.8, length 30mm)

Using the above spraying apparatus and concrete, the flow rate of the compressed air was adjusted by the valves 12 and 17 to spray the concrete, and the concrete drop rate and the like were evaluated by the following method. Table 1 shows the results.

[Evaluation Method] (Concrete Drop Rate) Concrete was sprayed at a speed of 8 m ³ / h for 10 minutes into a 5 m-high simulated tunnel made of an iron plate in an arch shape. Then, the concrete falling rate was calculated by the following equation. Concrete drop rate = (weight of concrete dropped without adhering to simulated tunnel) / (weight of concrete sprayed on simulated tunnel) x 100 (%)

(Steel fiber drop rate) The entire amount of steel fiber was taken out of the dropped concrete by using a magnet, the cement mortar component adhering to the steel fiber was washed off with water, and the water was dried to determine the weight of the dropped steel fiber. Calculated. afterwards,
The steel fiber drop rate was calculated by the following equation. Steel fiber drop rate = (weight of steel fiber recovered from dropped concrete) / (weight of steel fiber in sprayed concrete) × 100 (%)

(Transportability) The transport condition of concrete was observed. If the confluence pipe or transport pipe is not clogged, ○, if it seems to be clogged and concrete is intermittently discharged,
If the junction pipe or transport pipe is clogged and cannot be sprayed,
And

(Finished surface of sprayed concrete) The case where the thickness of the concrete was uniform and smooth was evaluated as ○, and the case where the finished surface of the concrete was uneven was evaluated as ×.

[0044]

[Table 1]

(Examples 4 to 6 and Comparative Example 3) For the shotcrete, the unit amount of each material was 650 kg / cement of cement.
m ³ , water 228 kg / m ³ , fine aggregate 1020 kg / m
^3. Coarse aggregate 441 kg / m ³ and steel fiber 78.5 kg /
m ³ and 0.8 parts by weight of a water reducing agent added to 100 parts by weight of cement.

Since the concrete has extremely high fluidity, the fluidity was evaluated not by the slump value but by the slump flow value. The measurement of the slump flow value is described in “Foundation,
Published by the Coastal Development Technology Center and the Fishing Port and Fishing Village Construction Technology Research Institute, underwater non-separable concrete manual, Appendix 1
The spread of the concrete was measured at two points in the perpendicular direction according to “Test of underwater non-separable concrete, slump flow test”. As a result, the slump flow value was 65 cm.

As the quick setting material, a mixture of 75 parts by weight of calcium aluminate and 25 parts by weight of aluminum sulfate was used, and 8 parts by weight was used for 100 parts by weight of cement in concrete.

With the spraying device used in the above embodiment,
The above-mentioned concrete was sprayed by adjusting the flow rate of the compressed air by the valve 12 and the valve 17, and the same evaluation as above was performed. Table 2 shows the results.

[0049]

[Table 2]

(Examples 7 to 9) Concrete was sprayed in the same manner as in Examples 4 to 6 and Comparative Example 3 except that the length of the transport pipe 5 was changed as shown in Table 3, and the same as above. An evaluation was performed. Table 3 shows the results.

[0051]

[Table 3]

(Examples 10 to 12 and Comparative Example 4) Except that the length of the transport pipe 8 was changed as shown in Table 4, Examples 4 to 12 were used.
6 and Comparative Example 3 were sprayed with concrete, and the same evaluation as above was performed. Table 4 shows the results.

[0053]

[Table 4]

[0054]

As described above, according to the present invention, the following effects can be obtained. (1) The pressure of the compressed air supplied to the branch pipe of the merging pipe 3 is 3
By adjusting to within the range of ~ 6 kg / cm ² , the concrete transport speed can be maintained within an appropriate range, and the concrete can be sufficiently dispersed in the compressed air and sprayed smoothly onto the ground. In addition, the amount of concrete falling due to rebound can be reduced. In addition, it is possible to prevent troubles due to blockage at the time of spraying and to reduce spraying cost.

(2) In particular, when the total amount of the compressed air supplied to the merging pipe 3 and the merging pipe 6 is adjusted within the range of 8 to 15 m ³ / minute in terms of the atmospheric pressure, the fluidity in a wider range is improved. It is possible to maintain the concrete transport speed within an appropriate range even for concrete having
The effect of can be fully exhibited.

(3) In particular, when steel fiber concrete is used as the shot concrete, the falling rate of the steel fiber can be reduced, and the shot concrete can be constructed closer to the design, and the construction cost can be reduced. It can be kept low.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one configuration example of a concrete spraying apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piston pump 2 Transport pipe 3 Merging pipe 4 Compressor 5 Transport pipe 6 Merging pipe 7 Quick binder supply device 8 Transport pipe 9 Blowing nozzle 10 Compressed air transport pipe 11 Flow meter 12 Valve 13 Pressure gauge 14 Rapid cement transport pipe 15 Compression Pneumatic transport pipe 16 Flow meter 17 Valve

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kenji Hatta 2209 Aomi, Aomi-cho, Nishikubiki-gun, Niigata F-term in the Aomi Plant of Denki Kagaku Kogyo Co., Ltd. 2D055 DB02 KA02 KA08

Claims (7)

[Claims] 1. Concrete is transported by a piston pump (1) via a transport pipe (2) to a junction pipe (3), and compressed air sent from a compressor (4) is supplied to a branch pipe of the junction pipe (3). The concrete is pneumatically transported to the junction pipe (6) via the transport pipe (5), and the junction pipe (6)
After supplying the quick-setting material which is pneumatically transported from the quick-setting material supply equipment (7) to the branch pipe and mixing the concrete and the quick-setting material, the concrete is transferred through the transport pipe (8) and sprayed through the spray nozzle (9). The pressure of the compressed air supplied to the branch pipe of the junction pipe (3) is 3 to 6 kg.
A method for spraying concrete, wherein the method is adjusted to fall within the range of / cm ² . 2. The method according to claim 1, wherein the total amount of compressed air supplied to the merging pipe (3) and the merging pipe (6) is adjusted to fall within a range of 8 to 15 m ³ / min in terms of an atmospheric pressure. Claim 1
The method for spraying concrete described in 1. 3. The transport pipe (5) has an inner diameter of 55-10.
The concrete pipe according to claim 1 or 2, wherein a pipe having a length of 5 mm or less and a length of 7 m or less is used, and the transport pipe (8) has an inner diameter of 55 to 105 mm and a length of 3 m or less. Spray method. 4. The concrete is transported by a piston pump (1) through a transport pipe (2) to a junction pipe (3), and compressed air sent from a compressor (4) is supplied to a branch pipe of the junction pipe (3). The concrete is pneumatically transported to the junction pipe (6) via the transport pipe (5), and the junction pipe (6)
After supplying the quick-setting material which is pneumatically transported from the quick-setting material supply equipment (7) to the branch pipe and mixing the concrete and the quick-setting material, the concrete is transferred through the transport pipe (8) and sprayed through the spray nozzle (9). A compressed air flow meter (1) between a compressor (4) and a compressed air transport pipe (10) connecting a branch pipe of a junction pipe (3).
1) and a valve (12) for adjusting the amount thereof, and a pressure gauge (1) between the valve (12) and the branch pipe of the merge pipe (3).
3) A concrete spraying apparatus characterized in that 3) is provided. 5. The valve according to claim 4, wherein the valve (12) is adjusted so that the indicated pressure of the pressure gauge (13) falls within a range of 3 to 6 kg / cm ² . Concrete spraying equipment. 6. A means for adjusting the flow rate of compressed air for transporting the quick-setting material, the adjusting means cooperating with the valve (12) and the merging pipe (3) and the merging pipe (6). 6) The total amount of the compressed air supplied is 8 to 15 m ³ /
The concrete spraying apparatus according to claim 4, wherein the apparatus is adjusted so as to be within a range of minutes. 7. An inner diameter of the transport pipe (5) and the transport pipe (8) is 55 to 105 mm, a length of the transport pipe (5) is 7 m or less, and a length of the transport pipe (8) is 3 m or less. The concrete spraying device according to any one of claims 4 to 6, characterized in that: