KR100807244B1 - Inorganic binder composition having high fire resistance and fire resistant board using it - Google Patents

Abstract

A high fire resistant inorganic binder composition is provided to secure the structure stability and the fire-resistance of high strength concrete at high temperature caused by fire, thereby preventing the sectional loss and explosive spalling of the concrete structure. A high fire resistant inorganic binder composition comprises 5-20 wt.% of fly ash, 5-20 wt.% of meta-kaolin, 35-70 wt.% of fine aggregate, 5-15 wt.% of an alkali stimulant and 5-10 wt.% of an alkali silicate solution. The composition further comprises at least one selected from the group consisting of an aqueous polymer dispersion, an organic fiber, anhydrite, calcium oxide and slack lime. A fire-resistant board is prepared by using the composition.

Description

Inorganic binder composition having high fire resistance and fire resistant board using it}

1 is a schematic diagram for explaining a process of spraying the highly refractory inorganic binder composition of the present invention.

2 is a view showing an example of a cross section of the structure to which the method of jointing the column surface or the wall surface of the fireproof board using the high refractory inorganic binder composition of the present invention.

Figure 3 is a schematic diagram for explaining the attachment of the refractory board of the present invention to stainless steel fittings.

Figure 4 is a schematic diagram for explaining the direct adhesion of the present invention by applying the composition of the present invention between the structure and the fireproof board of the present invention as an example of the method of attaching the fireproof board.

5 is an electron micrograph showing the microstructure of the surface of the composition of the present invention.

6 is a graph showing the change in compressive strength with temperature after curing of the composition of the present invention.

The present invention relates to an amorphous composition of a highly refractory inorganic binder suitable for protecting a structure from cross-sectional loss caused by explosion of a building column constructed of high-strength concrete, and an orthopedic lightweight fireproof board made of the composition.

In Korea, ALC or gypsum board is mainly used as the finishing material of the fireproof structure constituting the fire prevention section of a building, and calcium silicate board is used in foreign countries. However, ALC or gypsum board is very weak to moisture, and its strength is low, so it is easy to break and the cross section is increased to satisfy the fire resistance time required by regulations. In the case of calcium silicate board, It has a problem of high production cost due to restriction on use and import.

In addition, these products were used in fireproof compartments such as general strength concrete walls, and when high-strength concrete is applied, it is not suitable to satisfy the fire resistance of 3 hours. High-strength concrete is mainly applied to pillars of high-rise or columnar composite buildings, and has the advantage of high durability due to its compact structure and reduction of the cross-section of the pillars, but efficient use of space, but vulnerable to high temperatures such as fire, falling, pop-out and explosion. Cross section loss such as In particular, the explosive phenomena of high-strength concrete are suddenly exposed to high temperature during a fire, and when the temperature of the surface layer rises rapidly, water vapor is generated inside the concrete, condensation of the generated water vapor is concentrated, and water vapor pressure is formed on the surface layer, or a member subjected to compression or tension. This is due to thermal stress caused by constraining the expansion and contraction of the member due to the high temperature. In addition, when the explosion occurs, not only the fireproof time set by the building code is satisfied, but also seriously affect the structural safety. In spite of these problems, the concrete member was recognized as a fireproof structure, so the countermeasure was neglected and the fireproofing method was not applied.

The main object of the present invention is to solve the above problems and to provide a high refractory inorganic binder composition for securing the structural safety and fire resistance of high-strength concrete by high temperature such as fire.

Another object of the present invention is to provide a fireproof board made of a high refractory inorganic binder composition.

Another object of the present invention is to provide a method of applying the inorganic binder composition or the fireproof board of the present invention to a member such as a pillar or a beam.

Fly ash, metakaolin, fine aggregate, alkali stimulant, alkali silicate solution as an essential ingredient in the study of the present inventors for achieving the above object, and an amorphous composition using a light fine aggregate, aqueous polymer dispersion, organic fibers, etc. It is found that when the spraying construction or the lightweight board using the composition is applied and applied to concrete structures, it is possible to prevent the explosion by the fire of the members that need fireproof performance of high strength concrete structures and underground tunnels, and to ensure the fireproof performance. The invention was completed.

Therefore, according to the present invention, a high fire resistance containing 5 to 20% by weight of fly ash, 5 to 20% by weight of metakaolin, 35 to 70% by weight of fine aggregate, 5 to 15% by weight of alkali stimulant and 5 to 10% by weight of alkali silicate solution An inorganic binder composition is provided.

The inorganic binder composition of the present invention may further contain one or a mixture of two or more selected from the group consisting of aqueous polymer dispersion, organic fibers, anhydrous gypsum, quicklime and slaked lime.

Preferably, the inorganic binder composition of the present invention is based on the above-mentioned fly ash, metakaolin, fine aggregate, alkaline stimulant, and 100% by weight of the basic compound consisting of alkali silicate solution. 0.5 to 2.0% by weight of organic fibers, 1-3% by weight of anhydrous gypsum, 1-3% by weight of quicklime, and 1-3% by weight of calcined lime.

Hereinafter, the present invention will be described in more detail.

In the highly refractory inorganic binder composition of the present invention, the content of fly ash, metakaolin and fine aggregate is preferably 5 to 20% by weight, 5 to 20% by weight and 35 to 70% by weight, for the following reasons.

Fly ash hardly exhibits the potential hydrophobicity to hydrate itself, but can be coagulated and cured using strong alkali solution and alkali silicate solution as fly ash stimulant. When the content of the fly ash in the present composition is less than 5% by weight, the workability during the preparation of the inorganic binder refractory board is greatly reduced. When the content of the fly ash exceeds 20% by weight, the alkali activation reaction does not sufficiently occur, and thus the effect of improving the strength is low.

Metakaolin in the present composition has a superior effect than the case of incorporating silica fume, which is a conventionally used filler as a microfiller, and is an economical admixture because it is cheaper. When the content of metakaolin is less than 5% by weight, the inorganic binder is refractory. The workability during the manufacture of the board is greatly reduced, and if it exceeds 20% by weight the surface structure of the composition is not dense, the effect of improving the strength is low.

In the present composition, fine aggregates serve to fill the inorganic binder, and when the amount is less than 35% by weight, the amount of the binder increases, and when the amount exceeds 70% by weight, the strength and workability decrease.

In the composition of the present invention, as a fine aggregate, a lightweight fine aggregate having a specific gravity of 1.5 or less, a diameter of 5 mm or less, a specific gravity of 1.5 or more, a heavy fine aggregate having a diameter of 5 mm or more, or a mixture thereof can be used. Preference is given to using in amounts. Light weight aggregate is effective to control the density of the composition, and because of its high absorption rate, the construction property decreases according to the moisture absorption of the aggregate when compounding, so the light weight aggregate having less absorption rate is advantageous, and the weight of the composition is reduced by using the light weight aggregate. Can be. In the case of lightweight fine aggregates, commercially available lightweight fine aggregates can be used. When using lightweight aggregates that are fired by firing glass sludge, the surface of the aggregate is coated and the absorption rate is less than 5%. The density of the composition can be adjusted according to the mixing ratio without deterioration of the properties.

In the composition of the present invention, as the alkali stimulant, a potassium hydroxide or sodium hydroxide solution having a pH of 12 to 14 and a concentration of 3 to 12 mol (molar number of mol (mol) / volume of solution (L)) is preferable. As the alkali silicate solution, a sodium silicate, lithium silicate or potassium silicate solution having a silicon dioxide content of 20 to 30% by weight and a viscosity of 15 to 200 cP or more is preferable.

In this composition, the mixing ratio of the alkaline stimulant and the sodium silicate solution is 5 to 15% by weight of the alkaline stimulant and 5 to 10% by weight of the sodium silicate solution. If the amount of the alkali stimulant is less than 5% by weight, the ion supply of OH- required for the alkali activation reaction is reduced, and the strength-improving effect is low. If the amount exceeds 15% by weight, the finishing performance of the whitening phenomenon is reduced. In addition, when the amount of alkali silicate solution used is less than 5% by weight, it is difficult to express early strength, and when it exceeds 10% by weight, workability during manufacturing of the inorganic binder refractory board is greatly reduced.

 In addition, the present invention may further contain an aqueous polymer dispersion, organic fibers, anhydrous gypsum, quicklime, slaked lime and the like in order to improve physical properties in the high refractory inorganic binder composition.

The aqueous polymer dispersion can control the viscosity of the composition, improve the flowability and improve workability, and after curing, it is filled between the gaps of the composition to make the interior tight. This improves the durability of the test body and the composition due to the penetration of carbon dioxide. In addition, when exposed to a fire, it melts in the filled interior to form voids, thereby relieving expansion due to steam pressure and heat, which causes explosion such as cross-sectional damage, thereby reducing thermal stress, thereby preventing explosion that is likely to occur in high-strength concrete. The above characteristics are similar to the heat dissipation and stress relaxation mechanism of PP fiber. Examples of the polymer that can be used in such an aqueous polymer dispersion include styrene butadiene rubber (hereinafter referred to as SBR), polyacrylic acid ester (hereinafter referred to as PAE), ethylene vinyl alcohol (hereinafter referred to as EVA), methylcellulose (hereinafter referred to as MS), and the like. The preferred content of the aqueous polymer dispersion is 5 to 10% by weight with respect to 100% by weight of the basic blend of the present composition.

Organic fibers may be added to improve the explosion protection effect in a fire, and examples of such organic fibers include polypropylene (hereinafter referred to as PP) fibers and polyvinyl alcohol (hereinafter referred to as PVA) fibers. PP fibers are particularly preferable. . The preferred content of the organic fibers is 0.5 to 2.0% by weight with respect to 100% by weight of the basic compound of the present composition.

In addition, the preferred content of anhydrous gypsum, quicklime and hydrated lime is 1 to 3% by weight with respect to 100% by weight of the basic blend of the present composition.

The high refractory inorganic binder composition according to the present invention may be used for spraying, or the composition may be molded and cured by inserting a metal lath or the like to manufacture a regular refractory board.

As described above, in order for the fly ash to be mixed with the alkali stimulant and cured, an alkaline stimulant must be added to supply OH- ions in a sufficient amount. That is, the stimulant breaks out irregular three-dimensional chain bonds and elutes the modified ions such as Ca2 + and Al3 + entrapped inside, and the initial strength expression of the composition depends mainly on pH. It is a major factor in determining physical and chemical characteristics. These alkali activation reactions occur better at high temperatures and are more dense bonds between particles, resulting in better physical and chemical properties at higher temperatures.

Curing by alkali activation is different from the hydration reaction of cement and the decomposition of hydrate at high temperature requiring high fire resistance. In the case of cement hydrate, CSH-based hydrate, ethrinzite, monosulfate, calcium hydroxide (Ca (OH) ₂ ) is produced, and chemically bound water is dehydrated as the temperature increases. In particular, the calcium hydroxide is dehydrated in the range of about 450 ~ 550 ℃ and thereby the strength of the cement hardened body is reduced. However, the cured product by the alkali activation reaction does not form calcium hydroxide, so the decrease in strength is small even at a high temperature of about 500 ° C.

Unlike the gypsum board or calcium silicate board using natural raw materials, the high refractory inorganic binder refractory board that can be prepared using the present composition uses fly ash, which is an industrial by-product, and is economically advantageous because it does not undergo high temperature firing reaction. In addition, since a large amount of fly ash is generated as an industrial by-product in Korea, it can actively respond to the development of products for the replacement of natural resources and high value-added. Moreover, since alumina silicate is a main component, it can be said that the conditions favorable for manufacture of a highly refractory inorganic binder refractory board were provided.

As described above, the composition according to the present invention and the refractory board using the same have excellent fire resistance because the alkali reaction of the fly ash has a ceramic bond rather than a hydration reaction, and thus has thermal stability.

The composition of the present invention can be directly sprayed and attached to the concrete structure or to manufacture by attaching a fireproof board.

When manufacturing and attaching fireproof board, it is divided into two methods. The former is a method of directly attaching a fireproof board to a structure with a stainless steel fitting or a composition of the present invention. The latter is made of a fireproof board and integrated with concrete pouring. To attach.

1 illustrates a method of spraying with the composition of the present invention. The spraying method shown in the present invention is installed in the surface layer of the concrete structure 14 by installing a stainless steel wire 13 with a fitting iron 12 and a spacing of 1 to 2 cm by the concrete anchor 11 of the present invention as a spray gun 15 It is shown to spray the inorganic binder composition (1).

Figure 2 illustrates a method of constructing a fireproof board made of the composition of the present invention on the wall. In the illustrated method, after installing the anchor 11 to the concrete structure 14, the fittings 12 are mounted, and the fireproof board 10 is made of the composition of the present invention by using a stainless steel screw piece or a nut 16 or the like. End the joint 17.

In order to prevent explosion of the refractory board resulting from the lowering of the fireproof performance of the fitting hardware 12 and the explosion due to the rapid temperature rise of the dropped part, the stainless steel is more preferable than the galvanized iron which is commonly used as a material of the fitting.

3 is a plan view showing a method for attaching the stainless steel fittings 12 and the fireproof board 10 of the present invention with a stainless steel screw piece or nut 16.

4 shows the use of the fittings 12 and the composition 1 of the invention between them to attach the fire resistant board 10 of the invention to a high strength concrete structure 14. In the construction method of the present invention, the method of manufacturing a fireproof board in the form of formwork and integrating it when placing concrete has advantages in that it is not necessary to attach a fitting or a separate attachment and can be integrally constructed.

Hereinafter, embodiments of the present invention will be described in detail, and the scope of the present invention is not limited to these embodiments.

Example 1

Potassium hydroxide solution was used as alkali stimulant, and sodium silicate solution was selected as KS No. 3 standard sodium silicate solution to prepare an inorganic binder composition. The potassium hydroxide solution used was 12 moles and pH was 14.

After 12% by weight of fly ash, 12% by weight of metakaolin, and 60% by weight of fine aggregate aggregate, dry and mix, and then add 12 moles of potassium hydroxide solution 8% by weight and 8% by weight of liquid sodium silicate. Bibling for a second to prepare a high refractory inorganic binder composition. As shown in FIG. 1, the prepared composition was sprayed onto a concrete surface on which stainless steel meshes and fittings were installed, and then smoothly finished.

Example 2

The same procedure as in Example 1 was repeated except that 12 wt% of potassium hydroxide solution and 4 wt% of liquid sodium silicate were used.

[Comparative Example]

Using a composition containing 26% by weight of cement, 62% by weight of aggregate and 12% by weight of mixed water, the surface was sprayed on the concrete surface in the same manner as in Example 1, and then smoothly finished.

The compressive strength (MPa) according to the temperature change was measured at 3 days and 7 days after the construction of Examples 1 and 2 and Comparative Example 1, the measurement results are shown in Table 1.

Rebirth (Sun) Temperature (℃) Compressive strength (MPa) Comparative example Example 1 Example 2  3 20 19.1 30.2 15.8 200 32.3 49.3 54.7 400 25.0 34.2 40.1 600 16.7 27.4 34.1 800 6.3 16.4 23.4  7 20 24.9 31.9 21.4 200 35.3 51.1 55.9 400 25.2 35.3 45.0 600 17.6 30.0 36.7 800 8.4 18.6 23.7  28 20 39.5 47.1 30.1 200 45.5 52.8 58.9 400 42.9 41.0 49.8 600 25.2 33.5 41.1 800 13.9 21.4 29.4

As can be seen from the results of Table 1, the composition of the highly refractory inorganic binder of the present invention can improve the fire resistance of the high-strength concrete structure and can prevent the explosion of the concrete structure caused by the water vapor pressure and thermal stress of the initial fire. have. In recent years, as the construction of high-rise buildings and underground structures becomes more frequent, the risk of fire is also increasing. By applying the composition of the present invention, fire safety can be improved. At present, since the composition of the inorganic binder refractory material for securing safety against fire is mainly made of cement as a binder, it is difficult to secure fire resistance performance over the existing cement binder. In addition, gypsum board or calcium silicate board is mainly used when the refractory method using the fireproof board is applied, but gypsum board or calcium silicate board is weak in moisture and easily broken.

The present invention is excellent in usability because it can prevent the breakdown resulting from the rapid drop in strength and the lack of strength of the existing refractory board at a temperature of more than 500 ℃ of the cement binder, the composition can be used in the form or irregular form. In addition, when the high refractory inorganic binder fireproof board according to the present invention is applied, the fireproof performance is excellent compared to the existing gypsum board, so that the coating thickness of the member can be reduced or the number of sheets attached at the time of construction can be reduced. Since it can be secured, it is excellent in utilization, construction convenience and economic efficiency.

Since the above invention has a wide range of applications, it is possible to secure related new technologies, increase domestic technical skills in accordance with development and commercialization of related products, and secure world-class leading technologies by developing unique domestic technologies.

Claims (6)

5 ~ 20% by weight of fly ash, 5 ~ 20% by weight of metakaolin, 35 ~ 70% by weight of fine aggregate, 5 ~ 15% by weight of alkali stimulant, and 5-10% by weight of alkali silicate solution Composition. The high refractory inorganic binder composition according to claim 1, further comprising one or two or more mixtures selected from the group consisting of aqueous polymer dispersions, organic fibers, anhydrous gypsum, quicklime and hydrated lime. According to claim 2, based on 100% by weight of the base compound consisting of fly ash, metakaolin, fine aggregate, alkali stimulant and alkali silicate solution, 5-10% by weight of aqueous polymer dispersion, 0.5-2.0% by weight of organic fiber, anhydrous A high refractory inorganic binder composition, characterized in that it further comprises 1 to 3% by weight of gypsum, 1 to 3% by weight of quicklime, and 1 to 3% by weight of slaked lime. The method of claim 1, wherein the alkali stimulant is a potassium hydroxide or sodium hydroxide solution having a pH of 12 to 14 and a concentration of 3 to 12 molar concentrations (moles of solute / volume of solution (L)). High refractory inorganic binder composition. The high refractory inorganic binder composition according to claim 1, wherein the alkali silicate solution is a sodium silicate, lithium silicate or potassium silicate solution having a silicon dioxide content of 20 to 30% by weight and a viscosity of 15 to 200 cP. Fireproof board using the composition of any one of the claims 1 to 5.

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