KR100907442B1 - Spalling resistance structure of high strength concrete - Google Patents

Abstract

A spalling failure prevention structure of a high-strength concrete member is provided to improve the quality of construction with the simple dry work, to apply the structure to the new or already constructed structure, and to enough secure the fire extinguishing time and the taking shelter hour by delaying that structure is broken down by preventing spalling failure in a fire. A spalling failure prevention structure of a high-strength concrete member is composed of a high-strength concrete member(10), an inorganic insulation layer(30) formed in the outer side of the high-strength concrete member, a fire resistant board(20) adhered to the outer surface of the inorganic insulation layer, a finish board(50) adhered to the outer surface of the inorganic insulation layer, and an air layer. The fire resistant board is formed at the thickness more than 15mm, and has the fire-resistance efficiency in which backside temperature is controlled at 200-450°C for three hours. The inorganic insulation layer is formed as the board type inorganic heat insulating material having glass surface or rock surface in order to have the thermal conductivity less than 00.1kcal /mh°C.

Description

Spalling resistance structure of high strength concrete

The present invention relates to a explosion prevention structure of a concrete member to prevent the explosion phenomenon in the fire to delay the collapse of the structure to ensure sufficient evacuation time and fire suppression time of the internal user.

Recently, high-strength, high-strength concrete has been developed to cope with the recent rise of new buildings. The classification criteria for high-strength concrete vary depending on the classification institution, but generally means that the reference strength is 50 MPa or more on 28 days of age.

On the other hand, in order to maximize the heating effect of the building and to prevent heat loss, it is necessary to provide a separate insulation measure, such as in contact with the outside air in the building construction. Insulation is not only necessary for energy saving but also as a means for eliminating defects such as moisture proof and condensation prevention. In this regard, the Korean Building Law establishes the rules for building facilities and establishes insulation standards for each part of a building that is in direct and indirect contact with the outside air. This rule varies by region, but there are thermal insulation standards of 0.47 W / m² or less in the central region and 0.58 W / m² or less in the southern region.

Since the concrete contains moisture inside, if the concrete is heated by fire and there is a sudden temperature rise, the moisture inside the concrete vaporizes. At this time, the water vapor pressure inside the vaporized concrete exceeds the stress of the concrete and eventually causes severe cracks in the concrete. To the surface peeling or dropping occurs.

When the explosion occurs, the strength of the member due to the loss of the cross section of the concrete member decreases and the strength of the reinforcing steel increases due to the sudden rise of the temperature of the reinforcing bar, and further, the decrease of the strength and the cross section of the cast iron leads to the collapse of the concrete member. Preparing measures to prevent explosion is very important. In particular, the explosion phenomenon is more severe in high-strength concrete of 40Mpa strength or more than general concrete, because the higher the concrete strength, the more densely formed, the lower the internal porosity, and the vaporized water vapor is not effectively discharged due to heat. It is common for the explosion of high-strength concrete to occur within 30 minutes when the concrete is exposed to high temperature. This time is not enough time for internal users to evacuate. In high-rise or large buildings, the collapse of the structure due to the explosion of concrete can cause serious injury. Therefore, preparing for the explosion of concrete is an important task in the related industry.

Some countermeasures have been proposed to counteract the explosion of concrete.

The first is the method of incorporating weak organic fibers into heat during concrete production. This method is a principle to prevent the explosion by dissolving the organic fibers in the concrete in the process of heating the concrete to naturally form voids in the place of the organic fibers to the vaporized vapor is discharged to the outside through these pores. However, this method can be applied only to new building structures, so it cannot be applied to prevent explosion of existing buildings.

The second method is to mix lightweight aggregates such as perlite and fillers with fire and flame retardant properties in cement or gypsum binder and apply them to the structure as fire resistant coatings. However, such a coating method is not only poor workability due to the wet process, but also has a problem that it is difficult to secure its own strength because the hydration product of cement or gypsum used as a binder is destroyed at a high temperature. In other words, the hydrated gypsum hydrated gypsum is pyrolyzed in the range of 100 ~ 200 ℃ and the hydrated product of cement is pyrolysis in the range of 100 ~ 200 ℃ and calcium hydroxide in the range of 400 ~ 600 ℃. Refractory coating material made of gypsum binder loses its properties as a cured body in case of fire, making it difficult to secure its own strength. As a result, fire-resistant cladding made of cement or gypsum binder has some resistance to flame, but it is easy to fall off from the concrete member by the heat without blocking the heat transferred to the concrete member. You will not have a great effect. Furthermore, because the fireproof coating itself has a high water content, the moisture is retained in the fireproof coating layer after construction is absorbed or dried. Therefore, the coating method using the fireproof coating may act as another factor that causes the explosion phenomenon. .

The present invention has been developed to improve the above-mentioned problems, and can be applied to a new structure as well as a structure already constructed, and also to provide a explosion prevention structure of a concrete member that can improve the construction quality by a simple dry operation There is a problem.

The present invention has another technical problem to effectively provide a explosion prevention structure of a concrete member that can effectively prevent the explosion phenomenon in the fire to delay the collapse of the structure to ensure sufficient evacuation time and fire suppression time of the internal user.

The present invention to solve the above technical problem is a high-strength concrete member; A fireproof board attached to the surface of the high strength concrete member; And, an inorganic insulating layer formed on the outside of the fireproof board; provides an explosion-proof structure of the high-strength concrete member, characterized in that it comprises a. Further, it provides an explosion prevention structure of the high-strength concrete member formed in the air layer so as to contact the inorganic insulation layer at any one or more places inside and outside the inorganic insulation layer and finished with a finishing board.

In addition, the present invention is a high-strength concrete member; An inorganic insulating layer formed on the outside of the high-strength concrete member; And a fireproof board attached to the outer surface of the inorganic insulation layer. Furthermore, the air insulation layer is formed to contact the inorganic insulation layer at any one of the inside and the outside of the inorganic insulation layer, and also provides a finish preventing structure of the high strength concrete member as a finishing board.

According to the present invention, the following effects are expected.

First, since the fireproof board and the inorganic insulation layer is coated on the surface of the concrete member, it can be usefully applied to not only new structures but also already constructed structures. Furthermore, the thinning thickness of the fireproof board can maximize the effect of preventing explosion.

Second, because it uses a dry fireproof board can be constructed while securing a certain construction quality by a simple dry operation.

Third, because the explosion-proof structure is completed by the coating of the fireproof board and the inorganic insulation layer, it exhibits the explosion prevention effect in the case of fire and the insulation effect by the inorganic insulation layer in normal times. As a result, the structure to which the present invention is applied has an energy saving effect according to the thermal insulation performance improvement as well as the explosion prevention effect.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.

1 to 5 show an embodiment of the explosion prevention structure of the concrete member according to the present invention, as shown in the present invention, the inorganic insulating layer 30 and the fireproof board 20 in the high-strength concrete member 10 There is a technical feature to covering them together. In other words, the fire resistant board 20 and the inorganic insulation layer 30 are coated on the surface of the high strength concrete member 10 in the laminating order or vice versa, thereby improving the thermal insulation performance as well as the overall fireproofing effect. It was to exercise. As a result, while forming a thin coating of the refractory board 20 on the surface of the high-strength concrete member 10, it is possible to maximize the effect of preventing concrete detonation. As a result of the test through the following test example, it was confirmed that when the thin fireproof board 20 was coated with the inorganic insulating layer 30, the explosion prevention effect appeared. Such explosion prevention structure can be more usefully applied to the high-strength concrete member that the explosion phenomenon is serious.

In the explosion prevention structure according to the present invention, the fireproof board 20 is applicable as long as it is a dry fireproof board used in a conventional fireproof structure. However, considering that the explosion phenomenon occurs at 200 ~ 450 ℃ it is preferable to adopt a fire-resistant board 20 having a fire-resistant performance that is controlled to a temperature of 200 ~ 450 ℃ 3 hours, further exploding to the high-strength concrete member 10 Even if a phenomenon occurs, it is preferable to adopt a fireproof board having a thickness of 15 mm or more so as not to immediately lead to board dropout. In the present invention, a fireproof board made of a fireproof board composition for concrete of the Republic of Korea Patent No. 10-0704056 through the embodiment (fireproof board having an inorganic polymer bonding structure composed of alumino silicate-based binder, alkali silicate curing agent, thermal insulation aggregate, functional additives) Suggest to adopt).

In addition, in the thermally insulated structure according to the present invention, the inorganic insulation layer 30 is preferably formed to have a thermal conductivity of 0.1 kcal / mh ° C. or less, which is the surface of the high strength concrete member 10 according to the formation of the inorganic insulation layer 30. This is to make the heat transfer blocking effect to the inside and the outside more than a certain level. The inorganic insulation layer 30 refers to a heat insulation layer formed of an inorganic material, and is a concept that is in contrast to an organic insulation layer formed of an organic material. Unlike the organic insulation layer, the inorganic insulation layer 30 has a melting point of 500 ° C. or more. Such inorganic insulation layer enables the prevention of the explosion of concrete while adopting a fireproof board of a thin thickness, and furthermore exhibits the thermal insulation performance in ordinary times, so that the structure to which the explosion prevention structure according to the present invention is applied as a thermal insulation structure. The inorganic insulating layer 30 can be simply formed as a board-type inorganic insulating material made of glass or rock wool, and the inorganic insulating material contributes to the improvement of workability because it enables dry construction.

1 and 2 show the explosion prevention structure of the concrete member, which is completed by coating in the stacking order of the inorganic insulation layer 30 and the fireproof board 20 on the surface of the high-strength concrete member 10. Figure 1 (a) is an example of covering the surface of the high-strength concrete member 10 in the order of the inorganic insulation layer 30 and the fireproof board 20, Figure 1 (b) is a fireproof board 20 in Figure 1 (a) As an example in which the finishing board 50 is further attached to the outer surface, the surface of the high-strength concrete member 10 is coated in the order of the inorganic insulating layer 30, the fireproof board 20, and the finishing board 50. As an example in which the air layer 40 of the empty space is further formed inside the inorganic insulation layer 30 in FIG. 1B, the surface of the high-strength concrete member 10 is formed on the air layer 40, the inorganic insulation layer 30, and the fireproof board 20. , And is an example of coating in the order of the finish board (50). The fireproof board 20 and the finishing board 50 can be installed in a wet (glue, etc.) or dry (taker pin, etc.), the finishing board 50 is a gypsum board, magnesium board, usually used as a finishing material Any one of CRC board, calcium silicate board and MDF board can be adopted.

In particular, FIG. 2 shows an example in which the air layer 40 and the inorganic insulation layer 30 are formed at the same time by using a stud. FIG. 2 (a) is an example using a c-type stud 100a, and FIG. 2 (b) is asymmetric. This is an example using the C-shaped stud (100b). The c-shaped stud 100a is a c-shaped cross-section member formed of both flanges 110 and a web 120 as shown in FIG. 2 (a), and the pair of c-shaped studs 100a is spaced apart from each other between the two flanges 110. After arranging the open spaces to face each other, the webs 120 are fixed to the floor and the ceiling, respectively, at positions away from the surface of the high-strength concrete member 10, and face each other in the open spaces between the flanges 100 of the c-shaped studs. When the inorganic insulation layer 30 is formed to interconnect between the pair of C-shaped studs 100a disposed, the air layer 40 of the empty space is naturally as wide as the C-shaped stud 100a is disposed apart from the surface of the high-strength concrete member 10. Is formed. Asymmetric C-shaped stud (100b) is an asymmetric C-shaped cross-section member formed of a leaf 115 by bending only one end of one of the flanges 110 of the two flanges toward the web 120, as shown in Figure 2 (b) A pair of asymmetric C-shaped studs 100b are spaced apart from each other and the open spaces between the two flanges 110 face each other, and then the leaf 115 of the C-shaped studs closely adheres to the surface of the high-strength concrete member 10. When the inorganic insulation layer 30 is formed so as to be fixedly installed and interconnected between a pair of C-shaped studs 100b disposed to face each other in the open space between the flanges 110 of the C-shaped stud 100, the C-shaped studs The air layer 40 of the empty space is naturally formed by the width of the leaf 115.

3 and 4 show the explosion prevention structure of the concrete member completed by coating the stacking order of the fireproof board 20 and the inorganic insulation layer 30 on the surface of the high-strength concrete member 10. Figure 3 (a) is an example of covering the surface of the high-strength concrete member 10 in the order of the fireproof board 20 and the inorganic insulation layer 30, Figure 3 (b) is a finishing board 50 in Figure 3 (a) 4 is an example in which the air layer 40 in the empty space is formed inside the inorganic insulating layer 30 in FIG. 3 (b). In FIG. 4, the air layer 40 and the inorganic insulation layer 30 are formed using the c-shaped stud 100a or the asymmetric C-shaped stud 100b in the same manner as in FIG. 2.

FIG. 5 is an example in which the air layers 40 are formed on both sides (inside and outside) of the inorganic insulation layer 30 as an example of the modified example of FIGS. 2 and 4. It is easy to form the air layer 40 on both sides of the inorganic insulation layer 30 by using a symmetric C-shaped stud 100c. Symmetric C-shaped stud (100c) is a symmetric C-shaped cross-section member formed by the leaf 115, both ends of the flange 110 is bent toward the web 120, such a pair of symmetric C-shaped stud (100c) Spaced apart from each other and the openings between the two flanges 110 are disposed to face each other, and then the leaf 115 of the C-shaped studs are fixed to the surface of the high-strength concrete member and fixedly installed, and both flanges 110 of the C-shaped studs 100c are fixed. When the inorganic insulation layer 30 is formed to interconnect between a pair of C-shaped studs 100 facing each other in the opening space therebetween, the space of the hollow space is naturally formed on both sides by the width of the leaf 115 of the C-shaped stud 100. The air layer 40 is formed.

6 is a comparative example in contrast to the explosion prevention structure of the concrete member according to the present invention, Figure 6 (a) is coated on the surface of the high-strength concrete member 10 in the order of the fireproof board 20 and the finish board 50 6 (b) is an example in which an air layer 40, an inorganic insulation layer 30, and a finishing board 50 are coated on the surface of the high-strength concrete member 10. As in the following test example, it was confirmed that the comparative example of FIG. 6 did not exhibit an explosion effect. From this, it can be said that the thin fireproof board 20 has an advantageous effect on preventing explosion when it is coated with the inorganic insulation layer 30.

[Test Example 1]

In order to confirm that the explosion prevention structure of the concrete member according to the present invention exhibits the actual explosion prevention effect, fire resistance performance was tested using the examples shown in FIGS. 1 to 4 and the comparative example of FIG. 6 as test specimens.

(1) Test method

Six test specimens were prepared by constructing a coating structure as shown in Table 1 on a 60 MPa concrete test specimen having a strength of 200 mm × 200 mm × 300 mm (L × W × H), and tested as shown in FIG. 7. Specifically, the test was conducted by insulating the test specimens with refractory and applying a direct flame such that the surface temperature was 1100 to 1200 ° C., and measuring the final back temperature of each test specimen after 3 hours.

Cover structure of concrete member Example 1 (Fig. 1 (a)) Insulation layer + fireproof board Example 2 (Fig. 1 (b)) Insulation layer + fireproof board + finish board Example 3 (Fig. 2 (a)) Air layer + Insulation layer + Fireproof board + Finish board Example 4 (Fig. 3 (a)) Fireproof Board + Insulation Layer Example 5 (Fig. 3 (b)) Fireproof Board + Insulation Layer + Finish Board Example 6 (Fig. 4 (a)) Fireproof Board + Air Layer + Insulation Layer + Finish Board Comparative Example 1 (Fig. 6 (a)) Fireproof Board + Finish Board Comparative Example 2 (Fig. 6 (b)) Air layer + Insulation layer + Finish board (1) Fireproof board: Fireproof board (fireproof board having inorganic polymer bonding structure composed of alumino silicate-based binder, alkali silicate curing agent, heat insulating aggregate, functional additive) made of fireproof board composition for concrete of Patent 10-0704056 (2) Insulation layer: glass, 75T (heat conductivity 0.043W / mk, wall acid) (3) Air layer: 10T (4) Finish board: magnesium board, 6T

(2) Test result

As a result of the test, the explosion phenomenon did not occur in Examples 1 to 6 as shown in Table 2, but the explosion phenomenon was observed in Comparative Example 1 and Comparative Example 2. The opposite results of this example and the comparative example are evident from the temperature history of the test specimens of FIG. 8. In other words, the explosion usually occurs in the temperature range of 200 ~ 450 ℃ while in order to have a sufficient evacuation time it is required that the explosion does not occur for about 3 hours, as shown in Figure 5 Example 1 to Example 6 All showed the temperature history that the explosion phenomenon does not occur in general such that the temperature gradually increased until the temperature reached 200 ℃ only after 100 minutes after heating and reached below 400 ℃ even after 3 hours. And Comparative Example 2 withstand the explosive phenomena in less than 2 hours, such as showing a rapid temperature rise over 400 ℃ before and after 100 minutes after heating, the results are completely different according to the temperature history difference.

Final back side temperature (℃) Appearance after heating Example 1 (G1 of FIG. 6) 364.5 Good Example 2 (G2 of FIG. 6) 362.6 Good Example 3 (G3 in FIG. 6) 302 Good Example 4 (G4 of FIG. 6) 383.2 Good Example 5 (G5 of FIG. 6) 381.6 Good Example 6 (G6 in FIG. 6) 311.7 Good Comparative Example 1 (F1 of FIG. 6) - Explosion, board dropout Comparative Example 2 (F2 in Fig. 6) - Explosion, board dropout

Although the present invention has been described in detail with reference to the described embodiments, those skilled in the art to which the present invention pertains will be capable of various substitutions, additions and modifications without departing from the technical spirit described above. It is to be understood that such modified embodiments also fall within the protection scope of the present invention as defined by the appended claims below.

1 to 5 show an embodiment of the explosion prevention structure of the concrete member according to the present invention.

FIG. 6 shows a comparative example compared with the embodiment of FIGS. 1 to 4.

Figure 7 shows a test method for testing the explosion prevention performance of the Examples and Comparative Examples according to the present invention.

FIG. 8 shows the temperature history as a test result when the examples of FIGS. 1 to 4 and the comparative example of FIG. 6 are respectively tested according to the test method of FIG. 7.

<Description of the symbols for the main parts of the drawings>

10: high strength concrete member

20: fireproof board

30: inorganic insulation layer

40: air layer

50: finishing board

100a, 100b, 100c: stud

110: flange

120: web

Claims (7)

High strength concrete member 10; An inorganic insulating layer 30 formed outside the high-strength concrete member 10; A fireproof board 20 attached to an outer surface of the inorganic insulation layer 30; Consists of including The fireproof board 20 has a thickness of 15 mm or more and has a fireproof performance controlled at a temperature of 200 to 450 ° C. for 3 hours, The inorganic insulation layer 30 is a thermal explosion prevention structure of a high-strength concrete member, characterized in that formed of a board-shaped inorganic insulation material made of glass or rock surface to have a thermal conductivity of 0.1kcal / mh ℃ or less. In claim 1, The fireproof board 20, the explosion prevention structure of the high-strength concrete member, characterized in that it comprises a; further comprises a finishing board (50) attached to the outer surface. High strength concrete member 10; A fireproof board 20 attached to a surface of the high strength concrete member 10; An inorganic insulating layer 30 formed outside the fireproof board 20; Consists of including The fireproof board 20 has a thickness of 15 mm or more and has a fireproof performance controlled at a temperature of 200 to 450 ° C. for 3 hours, The inorganic insulation layer 30 is a thermal explosion prevention structure of a high-strength concrete member, characterized in that formed of a board-shaped inorganic insulation material made of glass or rock surface to have a thermal conductivity of 0.1kcal / mh ℃ or less. In claim 3, The finishing board 50 attached to the outer surface of the inorganic insulation layer 30; explosion-proof structure of the high-strength concrete member, characterized in that it comprises a further. The method according to any one of claims 1 to 4, The explosion prevention structure of the high-strength concrete member, characterized in that it further comprises; an air layer (40) of the empty space formed in contact with the inorganic insulation layer (30) inside or outside or both sides of the inorganic insulation layer (30). delete delete

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