JP2007132082A - Construction method of fireproof coated structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method of a fireproof coated structure for protecting various structures, buildings, and the like from a fire or the like to prevent explosion. <P>SOLUTION: Either one of a process of applying a primer to the juxtaposed surfaces of concrete segments or steel segments, and a process of fixing wire mesh at predetermined spaces, is performed first, or both processes are simultaneously performed. A fireproof coating material with a heat absorbing substance mixed in an inorganic binder is then sprayed or applied, and a net is pressed and embedded to carry out finishing construction. A spray gun 15 is supplied with air from an air compressor 14 through an air hose 5. Water 13 is fed by a water pump 10 and water hoses 11, 12 and mixed with the fireproof coating material 7 (powder) by a mortar mixer 8, and the kneaded fireproof coating material is supplied to the spray gun 15 through a mortar pump 9 and a mortar force-feed hose 6. The fireproof coating material mixed with air is then sprayed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a construction method of a fireproof covering structure capable of protecting various structures and buildings from a fire or the like and preventing explosion.

In shield tunnels that omit secondary construction, it is assumed that the segment will be exposed to flames in the event of a fire, resulting in high temperatures. When concrete is placed in a high-temperature environment, high-strength concrete having a high compressive strength, such as an RC segment, is more likely to cause an explosion phenomenon than ordinary concrete.
The reason for this is that, as the water-cement ratio becomes smaller, the concrete becomes denser, so it tends to explode, and as the water content, heating rate, and wall thickness increase, it is considered that the explosion tends to explode. Although it contains a lot of moisture inside, the tissue is not so dense, so even when placed in a high temperature environment, the moisture gradually escapes as the temperature rises. Therefore, there is almost no risk of explosion due to moisture, and there is almost no fireproof coating on the surface.
On the other hand, since the structure of high-strength concrete is very dense, when it is placed in a high-temperature environment, it is difficult for moisture to escape or the rate at which it escapes is slow. For this reason, there is a risk of explosion due to moisture, and it is necessary to apply a fireproof coating to the surface. However, no fireproof covering material that can sufficiently prevent explosion has been found at this stage.

Therefore, the present applicants have found a fireproof covering material and a fireproof covering structure disclosed in Patent Document 1 aimed at effectively preventing explosion of high-strength concrete.
Even when this fireproof covering structure is placed in a high-temperature environment such as a fire, the temperature of the high-strength concrete that is the base does not rise so much, and therefore, explosion of the high-strength concrete can be prevented.
Japanese Patent Laid-Open No. 11-116357

  However, in the fireproof coating material of Patent Document 1, since the coating thickness is limited, a fireproof coating layer having a sufficient thickness cannot be formed, and the movement of the high-strength concrete base cannot be followed. There was a possibility of causing.

  Therefore, the present invention provides a construction method for a fireproof coating structure that can control the thickness of the fireproof coating layer formed on the surface of various structures and buildings, and can prevent explosions by protecting from fire and the like. The purpose is to do.

  The present invention has been proposed in view of the above, and includes any one of a step of applying a primer to a surface on which a concrete segment or a steel segment is juxtaposed and a step of fixing a wire mesh across a predetermined space. After performing the process first or both processes at the same time, spray or paint a fireproof coating material containing an endothermic substance on the inorganic binder, press the net and embed it, then finish the construction. The present invention relates to a construction method of a featured fireproof covering structure.

  The present invention also proposes a construction method for a fireproof coating structure including a step of attaching a spacer with an anchor after applying a primer in the above construction method and fixing a wire mesh to the spacer.

  Further, according to the present invention, in the construction method described above, the fireproof coating material is composed of 100 parts by weight of an inorganic binder, 15 to 500 parts by weight of an endothermic substance, 10 to 200 parts by weight of an inorganic lightweight aggregate, and an organic lightweight aggregate 2. A construction method of a fireproof covering structure consisting of ˜20 parts by weight is also proposed.

  The construction method of the fireproof covering structure of the present invention can control the thickness of the fireproof covering layer formed on the surface of various structures and buildings, and can protect against fire and prevent explosion. Moreover, since it follows the movement of the foundation such as high-strength concrete, it does not cause peeling or dropping, and the durability is extremely high.

  The material used for this invention is demonstrated below.

[Wire mesh]
The wire mesh is intended to drop the fireproof coating material by being installed in the fireproof coating layer. For example, a commercially available product may be used, and the material and shape are not specified. The opening size of the wire mesh may be 50 mm × 50 mm to 150 mm × 150 mm, but preferably 100 mm × 100 mm is excellent in strength, spraying efficiency and bonding performance.

〔spacer〕
The spacer is for separating the wire mesh from the base with a predetermined space, and the thickness is determined by the construction thickness of the covering material, but is determined to be at the center of the construction thickness. In addition, this spacer is devised so that the wire mesh can be easily installed, and it is desirable that the spacer can be installed by one-handed work without deforming the wire mesh. As shown in FIG. The thing of the structure which has a shape which can be easily fastened so that there may be no burden is used suitably. An example of this suitable spacer is shown in FIG. The spacer 1 has a rising portion 1b formed substantially vertically from a rectangular fixed portion 1a, and an L-shaped portion 1c and an arc-shaped peak portion 1d extend in a branched shape at the upper end of the rising portion 1b. It is a shape, and the length (vertical width) of the rising portion 1b is the thickness of the space. And the fixing | fixed part 1a is distribute | arranged so that target bases, such as concrete, may be arranged, the L-shaped part 1c is located inside the wire mesh 2 (downward), and the arc-shaped peak part 1d is located outside the wire mesh 2 (upper). The wire mesh 2 is arranged so as to be sandwiched between the L-shaped part 1c and the arc-shaped peak part 1d from above and below (see also FIG. 7).

〔anchor〕
The anchor is for fixing the spacer to the ground, and there is no specification of the material and shape. The anchor may also serve as the spacer, that is, a spacer combined anchor.
FIG. 2 shows a state where the spacer 1 of FIG. 1 is attached using an anchor. The spacer 1 was placed along the concrete 4 and the anchor 3 was driven to attach the wire mesh 2.

〔Primer〕
The primer is for improving the adhesion between the base and the fireproof coating material, and a dedicated primer, a water absorption adjusting material, water, or the like is used. In the case where the ground is a concrete in which concrete segments are arranged side by side, a water absorption adjusting material and water are used, and in the case where the ground is a ground in which steel segments are arranged side by side, a resin mixed mortar and a resin primer are used.
More specifically, as the dedicated primer, SBR resin mortar “Fujikawa no Resin Mol” (manufactured by Fujikawa Construction Materials Co., Ltd.) and acrylic resin “Tika Mortar Dedicated Primer” (manufactured by Fujikawa Construction Materials Industry Co., Ltd.) are preferably used. For example, ethylene vinyl acetate resin “Sealex” (manufactured by Fujikawa Construction Materials Co., Ltd.) is preferably used.

  The step of applying the primer and the step of fixing the wire mesh may be performed either first or simultaneously. For example, after applying a primer first, you may fix a wire mesh with the said spacer and an anchor, and after fixing a wire mesh previously, you may make it apply a primer.

(Fireproof coating)
The fireproof coating material is kneaded with water by a mixer and sprayed with air from the tip of a hose by a pressure feed pump. Spraying is performed in two steps of undercoating and topcoating, but can be applied once depending on the coating thickness, and can also be applied with a trowel.
Although the specific composition of this fireproof covering material is mentioned later, the thing of the said patent document 1 can be used suitably, for example.

〔Net〕
The net is embedded in the surface of the fire-resistant coating material by pressing it with a trowel or the like (because it lies down), and the surface layer part of the fire-resistant coating layer is provided with integrity, flexibility, and rubber elasticity. Prevention of peeling of the coating material, prevention of cracks, and prevention of scattering of the fireproof coating material by stepping stones and the like are achieved.
The material and shape of the net are not specified and may be appropriately selected from a glass fiber net, an aramid fiber net, a vinylon fiber net, a carbon fiber net, and the like. In particular, a net having a mass of 40 to 250 g / m ² and a tensile strength of 100 kgf / mm ² or more is preferred from the record of use.

[Specific composition of fireproof coating]
Below, the fireproof covering material used for this invention is demonstrated.
As a suitable blend, it is composed of 100 parts by weight of an inorganic binder, 15 to 500 parts by weight of an endothermic substance, 10 to 200 parts by weight of an inorganic lightweight aggregate, and 2 to 20 parts by weight of an organic lightweight aggregate.

The inorganic binder is selected from hydraulic lime, natural cement, Portland cement, alumina cement, lime mixed cement, ettringite, mixed Portland cement, high sulfate slag cement, etc. The hydraulic cement is an essential component.
In addition to the hydraulic cement, a pneumatic cement selected from gypsum, dolomite, magnesia cement, and the like can be appropriately added and used.

The endothermic substance is defined as a substance that undergoes thermal decomposition and generates water in a high heat environment. Examples of substances that lose weight when heated from 100 ° C to 600 ° C include (1) aluminum oxide hydrates such as aluminum hydroxide, gibbite mineral, boehmite and diaspor, and (2) orthopyroxene , Zeolite materials such as hulandite and mordenite, (3) silica-alumina materials such as allophane, halloysite, non-foamed or foamed meteorite, (4) magnesia materials such as brucite and attapulgite, and (5) satin white. , Other substances such as ettringite, dolomite, boric acid. Of these, aluminum hydroxide is a particularly suitable endothermic substance because the proportion of OH groups in the total molecular weight of the molecular structure is larger than other substances and the production volume is high. This is because it is easy to do and safe.
This endothermic substance is blended in the range of 15 to 500 weights as described above, but when the amount is less than 15 parts by weight, the degree of slowing of the steel material temperature rise due to endotherm is small and the fire resistance is poor. When the amount exceeds 500 parts by weight, the amount of the binder is relatively reduced, and the strength required for practical use cannot be obtained.

The inorganic lightweight aggregate is a foamed or expanded material of natural minerals, such as expanded vermiculite, pearlite, expanded shale, pumice, shirasu balloon, etc., silica gel foamed materials, and various slags are granulated and foamed. Artificial lightweight aggregates such as those obtained by granulating and foaming glass scrap, and those obtained by granulating and foaming clay powder. Among these expanded or foamed substances, those which have not been vitrified so far as they are crystallized and have a low bulk specific gravity are preferable. For example, expanded vermiculite, perlite, pumice, and shirasu balloon are desirable.
This inorganic lightweight aggregate is blended in the range of 10 to 200 parts by weight as described above, but when it is less than 10 parts by weight, workability and fire resistance are inferior, and when it exceeds 200 parts by weight, mortar Strength cannot be obtained.

As the organic light-weight aggregate, synthetic resin or rubber foam is used, and examples thereof include polystyrene, polyethylene, polyethylene-vinyl acetate copolymer, polypropylene, polyurethane, polyvinyl chloride, polyvinylidene chloride, natural There are foams such as rubber and synthetic rubber. In addition, if it is lightweight, it does not necessarily need to be foamed, and a fibrous or non-woven material can also be employed.
This organic lightweight aggregate becomes more effective when the one having a particle size range of 0.3 to 2.5 mm is used. This is because workability and smoothness are improved when an organic lightweight aggregate in this range is used. When this organic lightweight aggregate has a particle size of less than 0.3 mm, the amount of water for obtaining a predetermined flow value increases and workability is reduced. On the contrary, the surface smoothness is lowered when a material larger than 2.5 mm is used.
The organic lightweight aggregate is blended in the range of 2 to 20 parts by weight as described above. When the fireproof coating is heated, the amount of heat received by the heating is used for changes such as melting of the organic lightweight aggregate, and the temperature rise of the fireproof coating is suppressed by the amount of heat used for the change and When the amount of the organic light-weight aggregate is less than 2 parts by weight, the above-mentioned action cannot be sufficiently exerted, so that the fire resistance is inferior. When the amount exceeds 20 parts by weight, the proportion of the material having less strength increases. Therefore, the strength of the mortar cannot be obtained.

  In addition, it is not limited to these components, The following components can be added suitably as needed. For example, powders such as refractory clay, refractory oxide, silica sand, and lime can be used as the filler. In addition, as a crack prevention or viscosity adjusting material, fibrous materials such as glass fiber, rock wool fiber, and pulp fiber, and surfactants can be employed. In addition, cellulosic water-soluble resins, liquid synthetic resin emulsions, or synthetic resin powders that become emulsions when mixed with water can be used as anti-sagging materials, anti-separation materials, and viscosity modifiers, which inhibit fire resistance. Therefore, an appropriate amount can be blended within a range where there is no problem in mechanical strength and adhesion.

  FIG. 3 shows a schematic view of forming a fireproof coating structure on the inner wall surface of the tunnel by the construction method of the present invention. FIG. 4 is an enlarged sectional view of a part of the formed fireproof coating structure. It is.

In FIG. 3, a primer (not shown) is already applied to the surface of the concrete 4, and the wire mesh 2 is fixed via the spacer 1 (anchor is not shown).
Air from the air compressor 14 is supplied to the spray gun 15 via the air hose 5. Further, the water 13 is fed by the water pump 10 and the water hoses 11 and 12, mixed with the fireproof coating material 7 (powder) and the mortar mixer 8, and the kneaded fireproof coating material is used for the mortar pump 9 and the mortar pressure feeding hose 6. To the spray gun 15. And the fireproof coating material kneaded with air is sprayed.

FIG. 4 shows a state where the net 17 is pressed and embedded on the surface with a trowel after the fireproof coating material is sprayed.
That is, the fireproof covering structure constructed according to the present invention has a primer 19 coated on the surface of the concrete 4 and the wire mesh 2 is fixed by the anchor 3 via the spacer 1 as shown in FIG. The fire-resistant coating material 18 is sprayed so that the wire mesh 2 is positioned in the layer of the fire-resistant coating material 18 to be formed, and the net 17 is embedded in the surface thereof and finished.

  As described above, the primer may be before or after fixing the wire mesh. For example, before fixing the wire mesh, the primer 19 can be applied with the brush 21 as shown in FIG. It is. After fixing the wire mesh, for example, the primer 19 may be sprayed from the outside of the wire mesh 2 using a sprayer 22 as shown in FIG.

  FIG. 7 shows a state in which the wire mesh 2 is installed using the spacer 1 in FIG. 1, but unlike FIG. 1, a state in which the attachment target surface is the upper surface is shown. Also in this case, the L-shaped portion 1c of the spacer 1 is mounted on the inner side (upper side) of the wire mesh 2 and the arc-shaped peak portion 1d is mounted on the outer side (lower side) of the wire mesh 2, so that the wire mesh 2 is L-shaped. Since it arrange | positions so that it may pinch | interpose between the shape part 1c and the arc-shaped peak part 1d, it can fix stably.

  FIG. 8 shows a state of spraying the fireproof coating material in the tunnel construction. An operator on the work carriage 20 applies the fireproof coating material 18 supplied by the mortar pressure hose 6 with the spray gun 15. Spraying and forming a fireproof coating layer on the upper and lower sides of the wire mesh 2.

  FIG. 9 shows a state in which the net 17 is laid down after the fire-resistant coating material 18 is sprayed, and the surface of the sprayed fire-resistant coating material 18 is not dried, and the surface of the net 17 using a trowel 23 is used. Bury (slay down).

  The construction example of the present invention is shown below.

<Construction Example 1>
Used for construction of box culvert fireproof coating material, Ninomiya-cho, Haga-gun, Tochigi Prefecture. Construction was performed on July 20, 2004, and construction time was used for construction of 16m ² in construction from 8 am to 5 pm. The materials, construction equipment, and construction procedures used in the construction are as shown in Table 1.

[Results of Construction Example 1]
There was the following evaluation from the person concerned.
There is no sag and rebound of the refractory material when spraying and there is little loss. In finishing, a net is installed on the surface of the refractory material, so it is smooth and very beautiful.
After one year, there were no cracks, no refractory material peeling or dropping, and no other abnormalities were observed.

<Comparative construction example 1>
Except not using a wire mesh and a spacer, the fireproof coating material construction was performed with the same material, construction equipment, and construction procedure as in the above-mentioned construction example 1. In this case, since the coating thickness is limited, the fireproof coating layer could not be formed with a predetermined thickness. Moreover, uniform coating thickness was not obtained.

[Results of Comparative Construction Example 1]
There was the following evaluation from the person concerned.
Compared to the construction example 1, the fireproof material sag and rebounded at the time of spraying compared with the construction example 1.

<Construction Example 2>
Used for construction of fireproof covering materials for buried tunnels in Kanazawa-ku, Yokohama City. Construction was performed on October 14, 2004, and construction time was 8 m ² for construction from 8 am to 5 pm. The materials, construction equipment, and construction procedures used for construction are as shown in Table 2.

[Results of Construction Example 2]
After one month, there were no cracks, no refractory material was peeled off, and no other abnormalities were observed.

<Comparison construction example 2>
Except not using a wire mesh and a spacer, the fireproof covering material construction was performed by the completely same material, construction equipment, and construction procedure as the said construction example 2. In this case, since the coating thickness is limited, the fireproof coating layer could not be formed with a predetermined thickness. Moreover, uniform coating thickness was not obtained.

[Results of Comparative Construction Example 2]
There was the following evaluation from the person concerned.
In comparison, sagging and rebounding of the refractory material was confirmed at the time of spraying as compared to Construction Example 2.

<Construction Example 3>
Ikebukuro Minami, Tokyo, used for shield tunnel fireproofing construction, construction period is from August 22, 2005 to August 26, 2005, construction time is 8m to 5pm, 180m ² Used for construction. The work was completed within the construction period from material delivery to concrete ground treatment, wire mesh installation, refractory material construction, and clean-up. The materials, construction equipment, and construction procedures used for construction are as shown in Table 3.

[Results of Construction Example 3]
In the confirmation after one month, there were no cracks, no refractory material peeling or dropping, and no other abnormalities were found.

<Comparison example 3>
Except not using a wire mesh and a spacer, the fireproof covering material construction was performed by the completely same material, construction equipment, and construction procedure as the said construction example 3. In this case, since the coating thickness is limited, the fireproof coating layer could not be formed with a predetermined thickness. Moreover, uniform coating thickness was not obtained.

[Results of Comparative Construction Example 3]
There was the following evaluation from the person concerned.
In comparison, sagging and rebounding of the refractory material was confirmed at the time of spraying as compared to the construction example 3.

By installing the wire mesh in this way, if an unexpected accident occurs, for example, even if an accident such as a major earthquake or car collision occurs and physical force is applied and the fireproof coating layer peels from the ground, The wire mesh can hold the fireproof coating layer and prevent falling.
Moreover, the anchor holding the wire mesh of the example has a holding power of three times or more even when considering the dynamic wind pressure condition, the weight of the refractory material in a wet state, and the weight of the wire mesh and the spacer.
The above can be confirmed as follows.
Under dynamic wind pressure conditions (244.9 kg / m ² = 81.63 kg / m ² × safety factor 3), the fireproof coating weight in the wet state (40 kgf / m ² ) and the weight of the mounting bracket (0.5 kgf / m ² ) Is added to a load of 285.4 kgf / m ² . However, since the fixing clip and the anchor are installed every 0.25 m ² (0.5 m × 0.5 m), the load applied to one anchor is 285.4 kgf / m ² × 0.25 m ² = 71. 4kgf. Here, since the anchor pull-out strength is 250 kgf or more, there is a holding force (pull-out resistance) that is three times or more.

<Workability test>
The fireproof coating materials of Formulation Examples 1 to 3 and Comparative Formulation Examples 1 to 3 having the compositions shown in Table 4 were prepared, workability tests were performed, and the results are also shown in Table 4.
1. Pump pumpability;
○… Can be installed without clogging or overloading ×… There is clogging or overloading, and there is a problem in construction. Sprayability, sagging;
○… No sagging ×: Many sagging occurs, causing problems in construction Sprayability, rebound;
○: Less material rebound ×: Many material rebound, causing problems in construction Finishability, net laying down;
○… Sinking can be done easily △… Slightly difficult to sink, and it takes time for construction ×… Sinking is difficult, and there is a problem in construction. Finishability, solderability;
○… It can be pressed smoothly. ×… It cannot be pressed smoothly.

[Results of workability test]

<Dynamic wind pressure test>
Durability against vehicle compression and suction (wind pressure test)
A vehicle traveling in a tunnel acts like a piston in a cavity in the tunnel.
The vehicle pushes the pressure wave forward in the direction of travel, air suction acts behind, and the fireproof coating may peel off and fall off. A test was conducted.

[Results of dynamic wind pressure test]
Table 5 shows the results of the dynamic wind pressure test in the fireproof coating material component.

・ Consideration The weight of refractory material sprayed on 1m ² (maximum thickness 40mm) is assumed to be 1.0g / cm ³ specific gravity.
1.0 × 0.04 (m ³ ) = 40.0 (kgf) = 392 (N),
The required bond strength is
392 (N) / 1 × 10 ⁶ (mm ² ) = 0.000392 (N / mm ² ).
Since the adhesion strength of the Thai mortar after dynamic wind pressure was 0.43 N / mm ² , it was confirmed that the adhesion strength was 1096 times.
Further, even when the safety factor of 3 was considered, the adhesive strength was 365 times.

<Pulling strength test of pin against concrete substrate>
Test method;
Specimen: W / C = 55%, concrete using quarrying and river sand with a unit water volume of about 170 kg / m ³ , according to the method stipulated in JIS A 5304 “Concrete for paving”, about 300 × 300 × 50 The dimensions were struck and demolded after curing for 24 hours in a test room. Thereafter, water curing was performed for 6 days, and what was cured in the test room until the material age was 28 days was used as a test base.
Test: An anchor pin was struck onto a test substrate by a predetermined method, and a pulling load was applied using a Kenken hydraulic tensile tester to obtain a maximum load.
Table 6 shows the results of the pulling strength test for the above fireproof coating material components.

[Results of pullout strength test]

・ Consideration There was sufficient pulling strength against the load considering the fireproof coating material, wire mesh, spacer, and dynamic wind pressure conditions.

<Bending test>
A bend test was performed when the openings of the wire mesh were # 50, # 100, # 150 and no wire mesh, and the supportability of the fireproof coating was compared.
Test method;
Test specimen: The test specimen was No. 2 (700 × 600) according to JIS A 1408 “Bending and impact test method for building boards”. The diameter of the wire mesh was 1.6 mm, and the test was performed without # 50, # 100, # 150 and no wire mesh. Spacers were arranged at intervals of 500 mm. For preparing the test body, a 12 mm thick plywood was cut into a size of 600 × 700 mm and prepared. A stainless mesh was placed, and a wire mesh was attached with a spacer. After attaching the wire mesh, the kneaded tie mortar was applied to a thickness of 15 mm, and after confirming the tightness of the tie mortar, it was applied again to a thickness of 15 mm. General curing (temperature 20 ° C. ± 2 ° C., humidity 65% ± 10%) was performed until the age of 28 days.
Test method: A universal testing machine (Shimadzu 1000 kN) was used, and bending was performed at three points, and the loading speed was 10 mm / min (100 N / min or more, or a maximum load in 1 to 3 minutes). The bending displacement was set to 100 mm and the state of the fireproof coating material was observed. Table 7 shows the bending test results for the above fireproof coating material components.

[Result of bending test]

・ Consideration It was confirmed that the installation of a wire mesh can prevent the dropout.

  It is applied to various structures and buildings where there is concern about explosion of concrete in a fire.

It is a perspective view which shows one Example of the spacer used suitably for this invention. It is a sectional side view which shows the condition which attached the wire mesh using the spacer of FIG. It is a schematic diagram for forming a fireproof covering structure. It is sectional drawing of a fireproof covering structure. It is a primer application condition figure. It is a primer application condition figure. It is a wire mesh installation method figure. It is a spraying situation figure of a fireproof covering material. It is a situation figure of the net lying down.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spacer 1a Fixed part 1b Standing part 1c L-shaped part 1d Arc-shaped mountain part 2 Wire mesh 3 Anchor 4 Concrete
5 Air hose 6 Mortar pressure feeding hose 7 Mortar (fireproof coating)
8 Mortar mixer 9 Mortar pump 10 Water pump 11 Water hose
12 Water hose 13 Water 14 Air compressor 15 Spray gun
17 Net 18 Fireproof coating material 19 Primer 20 Working cart
21 Brush 22 Sprayer 23 Iron

Claims (3)

  After performing either one or both of the steps of applying a primer to the surface on which concrete segments or steel segments are arranged side by side and fixing the wire mesh across a predetermined space A method for constructing a fire-resistant covering structure, characterized in that a fire-resistant covering material formed by mixing an endothermic substance is sprayed or applied to an inorganic binder, and a net is pressed to embed, followed by a finish construction.   The method for constructing a fireproof covering structure according to claim 1, wherein after applying the primer, the spacer is attached with an anchor, and the wire mesh is fixed to the spacer.   The fireproof covering material is composed of 100 parts by weight of an inorganic binder, 15 to 500 parts by weight of an endothermic substance, 10 to 200 parts by weight of an inorganic lightweight aggregate, and 2 to 20 parts by weight of an organic lightweight aggregate. The construction method of the fireproof covering structure of Claim 1 or 2.

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