JP7295678B2 - Rock wool spraying method - Google Patents

Description

The present invention relates to a rock wool spraying method.

A rock wool spraying method using rock wool, cement, and water is used for the purpose of imparting fire resistance, fire resistance, sound absorption, heat insulation, etc. to structural members. A dry construction method, a wet construction method, and a semi-dry construction method are known as the rock wool spraying method. The dry construction method and the semi-dry construction method have an advantage over the wet construction method in that the bulk density of the coating material layer (rock wool composition layer) formed by the rock wool spraying method can be reduced.
In the dry method, a mixture (cotton blend) of rock wool and cement that is pneumatically fed in a pressure feed pipe is sprayed from the blended cotton jet at the tip of the cotton blend pipe of a spray gun (spray nozzle). Rock wool, cement, and water are combined and mixed by injecting water from the water injection port at the tip of the water pipe arranged near the center of the cotton blend injection port of the gun, that is, at the central axis of the cotton blend pipe. It is a construction method in which the resulting combined mixture (rock wool composition) is formed as a coating material layer on the surface of the structure.

In addition, the semi-dry method is a rock wool spraying method that uses only rock wool instead of mixed cotton in the dry method, and cement slurry that is a mixture of water and cement instead of water (see, for example, Patent Document 1). ).
Although the semi-dry construction method generates less dust than the dry construction method, it cannot be said that the dust can be sufficiently suppressed.
Therefore, instead of a spray gun (center gun) in which the cement slurry injection port is arranged in the central axis of the rock wool pipe, a spray gun (center gun) in which the cement slurry injection port is arranged near the periphery of the rock wool It has been proposed to use a ring gun (see Patent Document 2, for example).

However, there is a problem that the ring gun is heavier than the center gun. In the case of the semi-dry construction method, the worker holds the spray gun to which the rock wool pressure hose and the cement slurry pressure hose are connected, and locks it to the pillar, beam, wall, etc. while adjusting the distance and direction to be appropriate. Since the work of spraying the wool composition is carried out over a day, the semi-dry rock wool spraying method using a ring gun is much more labor intensive than the case of using a center gun.

Japanese Patent Application Laid-Open No. 2002-348978 Japanese Utility Model Publication No. 02-033897

Therefore, although it is a semi-dry method using a center gun, there is a demand for a rock wool spraying method that generates less dust during the spraying operation. In addition, when the amount of water is too large for the amount of rock wool, the cement slurry pressure may increase, and there is a risk of bursting or falling off of the cement slurry pumping hose that pumps the cement slurry to the center gun. I found out I had a sexual problem.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a semi-dry rock wool spraying method that is less likely to generate dust during spraying, reduces work load during spraying, and is highly safe.

As a result of intensive studies by the present inventors, semi-dry rock wool spraying using a center gun was applied to a total of 100 parts by mass of cement and water in a rock wool composition formed as a coating material layer. The above problem is solved by adjusting the content ratio to 25 to 66 parts by mass and the content ratio of water to 1 part by mass of rock wool in the rock wool composition to be 1.35 to 3 parts by mass. The present invention was completed by finding that

That is, the present invention provides the following <1> to <4>.
<1> A rock wool pipeline having a rock wool injection port at its tip and a cement slurry pipeline having a cement slurry injection port at its tip, wherein the cement slurry injection port is the rock wool pipeline Rock wool and cement slurry are separately sent to a spray gun arranged substantially on the central axis of the rock wool, and the rock wool supplied to the rock wool pipeline is jetted from the rock wool jet port, and the By injecting the cement slurry supplied to the cement slurry pipe from the cement slurry injection port, the rock wool and the cement slurry are mixed together and sprayed onto the object to be sprayed, thereby forming a rock wool composition. A rock wool spraying method for forming a coating material layer consisting of
The content of rock wool with respect to a total of 100 parts by mass of cement and water in the rock wool composition is 25 to 66 parts by mass, and the content of water with respect to 1 part by mass of rock wool in the rock wool composition is , characterized by spraying so as to be 1.35 to 3 parts by mass,
Rock wool spraying method.

<2> The rock wool spraying method according to <1>, wherein the injection amount of the cement slurry is 1 to 15 kg/min.
<3> Rock wool spraying according to <1> or <2>, wherein the content of rock wool relative to 1 part by mass of cement in the rock wool composition is 0.8 to 20 parts by mass. Construction method.
<4> The rock according to any one of <1> to <3>, which is sprayed so that the content of rock wool relative to 1 part by mass of cement in the rock wool composition is 1.6 to 15 parts by mass. Wool spraying method.

Although the rock wool spraying method of the present invention is a semi-dry method that imposes a small work load during the spraying operation, dust is less likely to occur during the spraying operation and is highly safe.

1 is a conceptual cross-sectional view of an example of a spray gun (center gun) used in the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows an example of the spraying apparatus used for the rock wool spraying construction method of this invention. FIG. 3 is a cross-sectional view for explaining the internal structure of a fixed quantity supply device for rock wool included in the spraying device 20;

The rock wool spraying method of the present invention comprises a rock wool pipeline having a rock wool injection port at its tip and a cement slurry pipeline having a cement slurry injection port at its tip, and the cement slurry injection port is , Rock wool and cement slurry are separately sent to a spray gun arranged substantially on the central axis of the rock wool pipeline, and the rock wool supplied to the rock wool pipeline is sprayed with the rock wool jet. The cement slurry supplied to the cement slurry pipe is jetted from the nozzle, and the cement slurry supplied to the cement slurry pipe is jetted from the cement slurry jet port, so that the rock wool and the cement slurry are merged and mixed to be sprayed onto the target object. A rock wool spraying method of spraying to form a coating material layer composed of a rock wool composition, wherein the rock wool content is 25 with respect to a total of 100 parts by mass of cement and water in the rock wool composition. 66 parts by mass, and the content of water per 1 part by mass of rock wool in the rock wool composition is 1.35 to 3 parts by mass.

(Rock wool composition)
The rock wool composition is a composition formed as a coating material layer containing rock wool, cement and water. It shall refer to the value when it is sprayed on the object. By appropriately adjusting the solid content concentration of the cement slurry to be pumped to the spray gun, the injection amount of rock wool, the injection amount of cement slurry, etc., the content ratio and content of each component in the rock wool composition can be adjusted to the desired value. can be a range.

When the content of rock wool is less than 25 parts by mass with respect to the total of 100 parts by mass of cement and water in the rock wool composition, a spraying device such as that used for spraying rock wool for fireproof coating materials is used, the pressure of the cement slurry increases and there is a risk that the cement slurry pumping hose will burst or come off. Moreover, when the content of rock wool exceeds 66 parts by mass with respect to the total of 100 parts by mass of cement and water in the rock wool composition, the amount of dust during spraying increases.
The content of rock wool relative to the total 100 parts by mass of cement and water in the rock wool composition is 30 to 66 parts by mass in order to reduce the pressure of the cement slurry and reduce the amount of dust during spraying. It is preferably 35 to 66 parts by mass, and particularly preferably 40 to 66 parts by mass.

Further, when the content of water relative to 1 part by mass of rock wool in the rock wool composition is less than 1.35 parts by mass, the amount of dust generated during spraying increases, and when it exceeds 3 parts by mass, the cement slurry There is a risk that the pressure of the cement slurry will increase and the cement slurry pumping hose will burst or fall off.
The content of water in the rock wool composition is preferably 1.35 to 2.8 parts by mass, more preferably 1.55 to 2.7 parts by mass, based on 1 part by mass of rock wool.

In addition, the content of rock wool relative to 1 part by mass of cement in the rock wool composition is preferably 0.7 parts by mass or more, from the viewpoint of the absolute dry bulk density and heat insulating properties of the coating material layer made of the rock wool composition. More preferably 0.8 parts by mass or more, still more preferably 1 part by mass or more, still more preferably 1.2 parts by mass or more, still more preferably 1.5 parts by mass or more, still more preferably 1.6 parts by mass or more, particularly preferably is 1.9 parts by mass or more, and from the viewpoint of the shape retention performance of the coating material layer, it is preferably 20 parts by mass or less, more preferably 18 parts by mass or less, even more preferably 15 parts by mass or less, and particularly preferably 14 parts by mass. Part by mass or less.

In addition, the content of cement with respect to a total of 100 parts by mass of cement and water in the rock wool composition is preferably 1 part by mass or more, more preferably 2.5 parts by mass, from the viewpoint of the shape retention performance of the coating material layer. Above, more preferably 3 parts by mass or more, particularly preferably 4 parts by mass or more, and from the viewpoint of the absolute dry bulk density and heat insulation of the coating material layer made of the rock wool composition, preferably 60 parts by mass or less, More preferably 55 parts by mass or less, still more preferably 50 parts by mass or less, still more preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less.

In addition, the content of water with respect to a total of 100 parts by mass of rock wool and cement in the rock wool composition is preferably 50 mass from the viewpoint of the absolute dry bulk density and heat insulation of the coating material layer made of the rock wool composition. parts or more, more preferably 70 parts by mass or more, still more preferably 90 parts by mass or more, particularly preferably 105 parts by mass or more, and from the viewpoint of the shape retention performance of the coating material layer, preferably 300 parts by mass or less, and more It is preferably 280 parts by mass or less, more preferably 260 parts by mass or less, and particularly preferably 240 parts by mass or less.

In addition, the content of rock wool relative to a total of 100 parts by mass of rock wool and cement in the rock wool composition is preferably 35 from the viewpoint of the absolute dry bulk density and heat insulating properties of the covering material layer made of the rock wool composition. Part by mass or more, more preferably 45 parts by mass or more, still more preferably 55 parts by mass or more, particularly preferably 65 parts by mass or more, and from the viewpoint of the shape retention performance of the coating material layer, preferably 97.5 parts by mass Below, more preferably 95 parts by mass or less, particularly preferably 94 parts by mass or less.

In addition, the content of cement with respect to a total of 100 parts by mass of rock wool and cement in the rock wool composition is preferably 2.5 parts by mass or more, more preferably 5 parts by mass, from the viewpoint of the shape retention performance of the coating material layer. parts or more, particularly preferably 6 parts by mass or more, and preferably 65 parts by mass or less, more preferably 55 parts by mass or less from the viewpoint of the absolute dry bulk density and heat insulating properties of the coating material layer made of the rock wool composition. , more preferably 45 parts by mass or less, particularly preferably 35 parts by mass or less.

(spray gun)
The spray gun used in the present invention comprises a rock wool conduit having a rock wool injection port at the tip and a cement slurry conduit having a cement slurry injection port at the tip, and the cement slurry injection port is It is a spray gun arranged substantially on the central axis of the rock wool pipe, that is, a center gun. A representative example of such a center gun is the gun for spraying shown in FIGS. , or the inorganic fiber spray gun shown in FIG. 2 of Japanese Utility Model Publication No. 59-024384.

Here, the spray gun used in the present invention will be specifically described with reference to the accompanying drawings as necessary.
FIG. 1 is a conceptual cross-sectional view of an example of a spray gun (center gun) used in the present invention.
As shown in FIG. 1, the center gun 1 includes a rock wool conduit 2 having a rock wool injection port 22 at its tip and a cement slurry conduit 31 having a cement slurry injection port 3 at its tip. A cement slurry injection port 3 is arranged on the central axis 13 of the rock wool conduit.
The rock wool pipe 2 is a straight pipe, and the cement slurry pipe 31 is a bent pipe, both of which are preferably cylindrical. A part of the cement slurry pipe 31 (a region including the end opposite to the cement slurry injection port 3) protrudes to the outside from a pipe through-hole provided in the wall surface of the rock wool pipe 2. .
In addition, part of the cement slurry pipe 31 (the region including the cement slurry injection port 3 and the bent portion) is arranged along the central axis 13 of the rock wool pipe, and the cement slurry is mixed with rock wool. They are jetted in substantially the same direction. In addition, the cement slurry injection port 3 is housed in the rock wool pipeline 2 in a recessed state so as not to protrude from the tip of the rock wool pipeline 2 .

Further, the cement slurry pipe line 31 is provided with a cement slurry inlet at the end opposite to the cement slurry injection port 3, and the cement slurry inlet is connected to a cement slurry pumping hose. The rock wool conduit 2 is provided with a rock wool inlet at the end opposite to the rock wool injection port 22, and the rock wool inlet is connected to a rock wool pumping hose. The rock wool supplied from the rock wool inlet to the rock wool conduit 2 is injected from the rock wool injection outlet 22, and the cement slurry supplied from the cement slurry inlet to the cement slurry conduit 31 is injected from the cement slurry injection outlet. By jetting from 3, the rock wool and the cement slurry are merged and mixed. By spraying this merged mixture (rock wool composition) onto an object to be sprayed, it is possible to form a coating material layer made of the rock wool composition.

Here, in the present invention, rock wool refers to a material (mineral fiber) obtained by rapidly cooling a material mainly composed of rock, blast furnace slag, or the like melted in a melting furnace. For example, it also includes slag wool manufactured from materials mainly composed of blast furnace slag. As the rock wool used in the present invention, since a rock wool composition layer having low thermal conductivity and excellent shape retention performance is easily formed, it is possible to use a lumpy (granular) like rock wool granular cotton used in sprayed rock wool. things are preferred.
The injection amount of rock wool injected from the spray gun is preferably 0.5 to 10 kg/min, more preferably 0.5 to 10 kg/min, in order to reduce the amount of dust during spraying even in work that can be safely and efficiently performed with a small work load. is 1.5 to 7.5 kg/min, particularly preferably 3 to 5 kg/min.

The cement slurry used in the present invention contains cement and water as main components. The cement slurry contains, in addition to cement and water, alkali silicate, blast furnace slag powder, fly ash, metakaolin, silica fume, volcanic ash, igneous rock powder, igneous rock powder, and sewage sludge, in addition to cement and water. SiO ₂ -containing inorganic powders such as slag burnt powders and molten slag powders of municipal waste; alkali hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide; other admixtures and the like can be added. In addition, you may use only 1 type among these and may use it in combination of 2 or more types. Examples of alkali silicates include sodium metasilicate, sodium orthosilicate, lithium silicate, and potassium silicate.
The slurry concentration (solid content concentration) of the cement slurry used in the present invention is preferably 1 to 60% by mass, more preferably 2.5 to 60% by mass, still more preferably 3 to 55% by mass, still more preferably 4 to 50% by mass. % by mass, more preferably 4 to 40% by mass, particularly preferably 4 to 30% by mass. Here, when the solid content contained in the cement slurry is only cement, the slurry concentration is the cement concentration. When the slurry concentration (solid content concentration) is within the above range, the amount of dust generated can be suppressed while suppressing the pressure of the cement slurry during spraying, the shape retention performance of the coating material layer is excellent, and the coating material layer per unit time The amount of formation of is sufficient, and the workload can be suppressed. In addition, the absolute dry bulk density and heat insulating properties of the covering material layer are also improved.

In addition, in the present invention, the injection amount of the cement slurry injected from the spray gun is an efficient, safe and small amount of dust using a spraying device used for spraying rock wool for refractory coating materials. It is preferably 1 to 15 kg/min because it can be applied in a short time, and more preferably 2 to 14 kg/min because the work load during spraying can be reduced.
By setting the injection amount of cement slurry to 1 kg/min or more, the amount of dust during spraying can be reduced without suppressing the injection amount of rock wool per unit time. Therefore, it is possible to increase the amount of coating material layer formed per unit time while suppressing the amount of dust, thereby improving the construction efficiency, shortening the spraying work time, and reducing the work load.
In addition, by setting the cement slurry injection amount to 15 kg/min or less, the pressure of the cement slurry can be suppressed even when using a spraying apparatus used for spraying rock wool for fireproof coating materials, for example. can. Safety can be improved without increasing the workload such as increasing the size of the spray gun or the inner diameter of each hose.

In the rock wool spraying method of the present invention, the content of rock wool with respect to a total of 100 parts by mass of cement and water in the rock wool composition is 25 to 66 parts by mass, and 1 part by mass of rock wool in the rock wool composition Except for spraying so that the content of water is 1.35 to 3 parts by mass, it may be carried out in the same manner as the semi-dry rock wool spraying method using a general center gun.
For example, the spraying device whose schematic diagram is shown in FIG. 2 can be preferably used.
The spraying device 20 shown in FIG. 2 includes the center gun 1 shown in FIG. 9, a cement slurry pump 7, a cement slurry pumping hose 6, a suction hose 14, a cement slurry storage tank 8, and the like. In addition to these, a cement slurry preparation mixer may be provided (not shown).

The rock wool 11 to be fed into the hopper portion of the rock wool constant supply device 10 is packed in a thick plastic bag in a state in which granular cotton as shown in FIG. After being unwound in the provided dissolving section, it is sent by a feeder to a rock wool pumping pipe provided in the rock wool constant supply device 10 . The loosened rock wool 5 is supplied to the rock wool conduit 2 of the center gun 1 through a rock wool pressure-feeding hose 9 connected to the rock wool pressure-feeding pipe by an air current generated by a blower 12 connected to this pressure-feeding pipe. , through the rock wool conduit 2 and jetted from the rock wool jet port 22 .

In addition, the cement slurry is prepared by the cement slurry preparation mixer and then put into the cement slurry reservoir 8, or prepared by the cement slurry preparation mixer in the cement slurry reservoir 8. It is stored in the slurry storage tank 8 .
In addition, the tip of the suction hose 14 connected to the cement slurry pump 7 is put in the cement slurry in the cement slurry storage tank 8, and the operation of the cement slurry pump 7 causes the inside of the cement slurry storage tank 8 to Cement slurry is sent to the cement slurry pressure-feeding hose 6 .
That is, when the cement slurry pump 7 is operated, the cement slurry in the cement slurry storage tank 8 is pumped through the suction hose 14 to the cement slurry pumping hose 6, and further connected to the cement slurry pumping hose 6. It is injected from the cement slurry injection port 3 through the cement slurry pipe line of the center gun 1 . The cement slurry 4 sprayed in this manner is joined and mixed with the loosened rock wool 5 sprayed from the rock wool spray port 22, and the surface of the sprayed object such as a wall, ceiling, pillar, beam, etc. The substrate) is formed with a coating material layer (rock wool composition layer) composed of a rock wool composition containing rock wool, cement, and water as main components.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples.

(Test Nos. 1 to 17, 19 to 32)
Cement and water are mixed to prepare a cement slurry, and a general method using an apparatus equipped with a center gun (a center gun manufactured by Shinwa Co., Ltd. (nozzle hole diameter: 3 mm, diffusion tip angle: 20°)) shown in the schematic diagram of FIG. The cement slurry was sprayed onto the wall surface together with rock wool by a semi-dry rock wool spraying method to form a coating material layer (rock wool composition layer) composed of a rock wool composition, and an evaluation test was performed. Table 1 shows the compounding conditions at this time, Table 2 shows the spraying conditions, and Table 3 shows the evaluation test results. The following materials were used. In the spraying, the distance between the center gun (rock wool injection port) and the wall surface was set to 50 cm.
(Test No. 18)
A commercially available ring gun (slurry gun (K) manufactured by Shinwa Co., Ltd. (number of cement slurry injection ports: 8)) was used instead of the center gun, and a compressor was connected to the ring gun to introduce compressed air into the cement slurry injection port. The evaluation test was performed in the same manner as above, except that the cement slurry was diffused.

(Material used)
・Cement: Ordinary Portland cement, symbol: C
・Rock wool: Rock wool granulated cotton manufactured by Taiheiyo Materials Co., Ltd. “Taiheiyo Mineral Fiber Granular Cotton” (trade name), symbol: RW
・Water: tap water, symbol: W

(Evaluation test)
Cement slurry pressure was measured, work load was evaluated, and the amount of dust generated during spraying was measured. Moreover, while measuring the absolute dry bulk density of the formed rock wool composition layer, the shape retention property was confirmed.
Table 3 shows the results of the evaluation test.

・Pressure of cement slurry A pressure gauge was placed in the pumping path of the cement slurry to measure the pressure.
If the pressure of the cement slurry exceeds 1.0 MPa, the cement slurry pumping hose may burst or come off. evaluation) was set as "bad" (symbol: x), and when the pressure of the cement slurry was 1.0 MPa or less, the evaluation of safety (evaluation of cement slurry pressure) was set as "good" (symbol: ○).
In addition, when the pressure of the cement slurry exceeded 1.0 MPa and the safety evaluation (evaluation of the cement slurry pressure) was "bad", the spraying work was stopped, so the work load was evaluated, the amount of dust was measured, Measurement of absolute dry bulk density and evaluation of shape retention were not conducted.

・Work load Compared to the general semi-dry rock wool spraying method using a center gun, the work load is considered to be large (symbol: ×), and the general semi-dry method using a center gun When the work load was considered to be less than the same level as the rock wool spraying method of the dry method, it was evaluated as "low load" (symbol: ○).

・Measurement of dust amount By sucking the work environment air during the spraying work under the construction conditions shown in Table 2 using a Makita rechargeable cleaner (model: CL107FD), floating dust is removed with a Makita dust bag (model: A-48511), and the amount of dust was easily measured by measuring the weight of the collected dust. Working environment air was sucked for 90 seconds using a rechargeable cleaner at a position 50 cm away from the spraying position (spraying operator) (a position 100 cm away from the wall). After collection, the weight of the dust bag was measured to the nearest 0.01 g, and the increment from the mass of the dust bag measured before collection was taken as the amount of dust. The average value of three measurements made under the same conditions with different dust bags was taken as the amount of dust.
If the average amount of dust collected in 90 seconds is 0.10 g or less, it is "excellent (small amount of dust)" (symbol: ◎). much)” (symbol: x).

Bone-dry bulk density After measuring the spray thickness t (cm) of the rock wool composition layer sprayed on the wall under the construction conditions shown in Table 2, cut it into a cylindrical shape with a diameter of 8 cm with a bulk density measuring cutter. The rock wool composition layer was cut and dried in an oven at 110° C. to constant weight. Using the mass w (g) after drying, the absolute dry bulk density ρ (g/cm ³ ) was calculated according to the following formula (1). The average value of three measurements under one condition was taken as the absolute dry bulk density.

(Number 1)
ρ (g/cm ³ ) = w/(A x t) (1)
(Here, A is the cross-sectional area of the sample, 4×4×π (cm ² ))

The absolute dry bulk density ρ of the rock wool composition is “slightly good” (symbol: Δ) when it is more than 0.50 g/cm ³ and 0.80 g/cm ³ or less, and more than 0.40 g/cm ³ and 0.50 g/cm ³ . Below is "good" (symbol: ○), 0.26 g/cm ³ to 0.40 g/cm ³ is "excellent" (symbol: ◎), 0.26 g/cm ³ or less is "best" (symbol: ◎ ◎).

・Shape Retention After spraying a rock wool composition onto a mold of 200 mm × 200 mm × 30 mm by a spraying method under the construction conditions shown in Table 2 and holding it with a trowel, curing it until it reaches a constant weight, the mold Then, an air blower was used to apply an external pressure (wind speed of 5 m/s or 10 m/s) in the vertical direction to the sprayed material for 10 minutes.
After blowing air, check the outer shape of the sprayed material. If the outer shape is not deformed even when the air is blown at a wind speed of 10 m/s, the shape retention performance is "excellent" (symbol: ◎). However, if no deformation is observed in the sprayed material at a wind speed of 5m/s, the shape retention performance is "good" (symbol: ○), and deformation is observed in the sprayed material at a wind speed of 5m/s. In some cases, it was evaluated as “slightly good” (symbol: △).

・Comprehensive evaluation If the evaluation of safety (evaluation of cement slurry pressure) is "poor" (symbol: ×), if the evaluation of work load is "large load" (symbol: ×), or if the evaluation of dust amount is " In the case of "insufficient dust suppression (a large amount of dust)" (symbol: x), the comprehensive evaluation was evaluated as "insufficient" (symbol: x).
In addition, the evaluation of safety (evaluation of cement slurry pressure) was “good” (symbol: ○), the evaluation of work load was “low load” (symbol: ○), and the evaluation of dust amount was “excellent” (the amount of dust was low). small)” (symbol: ◎), and the evaluation of absolute dry bulk density is “slightly good” (symbol: △) or the evaluation of shape retention is “slightly good” (symbol: △) , and the overall evaluation was evaluated as "slightly good" (symbol: △).
In addition, the evaluation of safety (evaluation of cement slurry pressure) was “good” (symbol: ○), the evaluation of work load was “low load” (symbol: ○), and the evaluation of dust amount was “excellent (small amount of dust”). )” (symbol: ◎), the evaluation of absolute dry bulk density is “good” (symbol: ○), and the evaluation of shape retention is “excellent” (symbol: ◎), comprehensive evaluation evaluated as "good" (symbol: ○).
In addition, the evaluation of safety (evaluation of cement slurry pressure) was “good” (symbol: ○), the evaluation of work load was “low load” (symbol: ○), and the evaluation of dust amount was “excellent (small amount of dust”). )” (symbol: ◎) If the evaluation of absolute dry bulk density is “excellent” (symbol: ◎) and the evaluation of shape retention is “excellent” (symbol: ◎), the overall evaluation is It was evaluated as "excellent" (symbol: ⊚).
In addition, the evaluation of safety (evaluation of cement slurry pressure) was “good” (symbol: ○), the evaluation of work load was “low load” (symbol: ○), and the evaluation of dust amount was “excellent (small amount of dust”). )” (symbol: ◎) If the evaluation of absolute dry bulk density is “best” (symbol: ◎) and the evaluation of shape retention is “excellent” (symbol: ◎), comprehensive evaluation evaluated as “best” (symbol: ⊙).

1 Center gun 2 Rock wool pipe 3 Cement slurry injection port 4 Cement slurry 5 Thawed rock wool 6 Cement slurry pumping hose 7 Cement slurry pump 8 Cement slurry storage tank 9 Rock wool pumping hose 10 Fixed quantity supply for rock wool Device 11 Rock wool 12 Blower 13 Central axis 14 of rock wool pipeline Suction hose 20 Spray device 22 Rock wool injection port 31 Cement slurry pipeline

Claims (4)

A rock wool pipeline having a rock wool injection port at its tip and a cement slurry pipeline having a cement slurry injection port at its tip, wherein the cement slurry injection port is located substantially at the center of the rock wool pipeline. Rock wool and cement slurry are separately sent to a spray gun arranged on the shaft, and the rock wool supplied to the rock wool pipeline is jetted from the rock wool injection port, and the cement slurry is sprayed. By injecting the cement slurry supplied to the pipeline from the cement slurry injection port, the rock wool and the cement slurry are mixed together and sprayed onto the object to be sprayed to form a coating made of the rock wool composition. A rock wool spraying method for forming a material layer,
The injection amount of the cement slurry is 1 to 15 kg/min, the content of rock wool with respect to a total of 100 parts by mass of cement and water in the rock wool composition is 25 to 66 parts by mass, and the rock wool The water content ratio of 1 part by mass of rock wool in the composition is 1.35 to 3 parts by mass.
Rock wool spraying method. The rock wool spraying method according to claim 1 , wherein the rock wool composition is sprayed so that the content of rock wool is 0.8 to 20 parts by mass with respect to 1 part by mass of cement. The rock wool spraying method according to claim 1 or 2, wherein the rock wool composition is sprayed so that the content of rock wool per 1 part by mass of cement is 1.5 to 18 parts by mass. Rock wool spraying according to any one of claims 1 to 3, wherein the rock wool composition is sprayed so that the content of rock wool per 1 part by mass of cement is 1.6 to 15 parts by mass. Construction method.

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