KR20080102975A - Composition for high strength concrete for preventing explosive rupture - Google Patents

Abstract

A composition for high-strength concrete for preventing explosive rupture is provided to prevent the explosive rupture of the high-strength concrete when a fire is generated, to control temperature inside the concrete, to increase a residual intensity after the fire breaks out by enhancing unity a force of the concrete structure and to secure safety to the fire of the ultra-high-rise structure. A composition for high-strength concrete comprises a binding material of 100 parts by weight, water 15 - 40 parts by weight and a chemical admixture 0.5-4.0 parts by weight. The binding material 100 parts by weight comprises cement 40 - 95 weight% and a blending material 5 - 60 weight%. The composition for the concrete additionally includes an organic synthetic fiber selected from an olefin group fiber including a polyethylene, a polyamide fiber including a nylon, a polyacryl fiber, a polyester fiber, a polypropylene fiber and a polyvinyl alcohol fiber. The blending material is selected from a group consisting of fly ash, blast furnace slag, silica fume, polymer, pozzolan and metakaolin. The chemical admixture is selected from a group consisting of an AE agent, a water reducing agent, an AE water reducing agent, a fluidifier and a promoter.

Description

Composition for high strength concrete for preventing explosive rupture}

The present invention relates to a composition for high strength concrete for preventing explosion.

Recently, as reinforced concrete structures such as high-rise structures, large bridges, and high-speed railways become super tall, large, and specialized, interest in high-strength concrete is increasing and its use is expected to increase.

In the case of using high-strength concrete for high-rise structures, the cross-section of vertical members such as columns and walls increases in the lower floor due to the increase in the weight of the building, and the horizontal displacement increases due to the increase of the horizontal load (wind, earthquake, etc.) in the higher floor. It can have a serious impact on the safety and usability of the structure, and there is a disadvantage in that the economic efficiency of the structure is reduced due to the reduction of the use area due to the increase of the cross section. In contrast, high-strength concrete is a structural material that is used very effectively in high-rise structures, it has the advantage of burdening high loads and reducing the cross-section according to the increase in strength.

High-strength concrete refers to concrete that is stronger than ordinary concrete, but its meaning varies greatly depending on the times and regions. In Korea, the concrete standard specification defines concrete with strength above 40MPa as high strength concrete.

However, high-strength concrete is manufactured to exhibit great compressive strength and good durability, and in order to satisfy this performance, the internal structure of the concrete structure is very dense compared with general concrete, so that the explosion phenomenon is severe when a fire occurs. That is, the steam pressure is generated inside the concrete structure due to the high temperature generated when the fire occurs, but due to the dense structure of the high-strength concrete, there are few pores that can absorb the vapor pressure, so that the vapor pressure is not effectively discharged. Therefore, when the water vapor pressure exceeds the tensile strength of the concrete, the concrete peels off and falls off along with severe binge drinking.

In addition, when the reinforcing bar is exposed inside the concrete due to such a explosion phenomenon may collapse the structure due to the decrease in the strength of the main structural member.

The present invention is to provide a composition for preventing high-strength concrete that can prevent the explosion phenomenon of high-strength concrete in the event of fire and increase the binding strength of the concrete structure to increase the remaining strength.

According to an aspect of the present invention, for high strength concrete including 15 to 40 parts by weight of water and 0.5 to 4.0 parts by weight of chemical admixtures based on 100 parts by weight of the binder including 40 to 95% by weight of cement and 5 to 60% by weight of admixture The composition, the composition for concrete further comprises an organic synthetic fiber, the content of the organic synthetic fiber is provided with a composition for preventing high-strength concrete is contained so that the content of 0.01 to 5.0 kg per m ^{3 of the} composition for concrete.

The composition for preventing high-strength concrete may further comprise 0.05 to 5.0 wt% steel fiber based on the weight of the concrete.

The steel fibers may have a shape ratio of 2 to 5,000, and the organic synthetic fibers and steel fibers may be mixed in a weight ratio of 1: 0.1 to 1:10.

The organic synthetic fibers may be at least one selected from the group consisting of olefinic fibers including polyethylene, polyamide based fibers including nylon, polyacrylic fibers, polyester fibers, polypropylene fibers and polyvinyl alcohol fibers.

The organic synthetic fibers may have a shape ratio of 10 to 10,000, start melting at 150 degrees Celsius, and have a weight residual ratio of 0 to 20% at 300 degrees Celsius.

The composition for preventing high-strength concrete may further include 0.1 to 5 parts by weight of the fiber dispersant based on 100 parts by weight of the binder.

The admixture may be at least one selected from the group consisting of fly ash, blast furnace slag, silica fume, polymers, pozzolane and metakaolin.

The chemical admixture may be at least one selected from the group consisting of an AE agent, a water reducing agent, an AE water reducing agent, a fluidizing agent, and an accelerator.

Other aspects, features, and advantages other than those described above will become apparent from the following drawings, claims, and detailed description of the invention.

In case of fire, the explosion of high-strength concrete can be prevented, and the temperature inside the concrete can be controlled. In addition, it is possible to increase the binding strength of the concrete structure to increase the residual strength after the fire occurs to ensure the safety of fire of the high-rise structure.

Before describing an embodiment of the composition for high-strength concrete for explosion prevention according to the present invention will be briefly described for the mixing design of concrete.

The mix of concrete refers to the ratio of each material constituting the concrete, that is, the mix ratio of cement, aggregate, water, and mixed materials, and the mix design refers to the required strength, durability, slump, unit weight, water tightness, and workability. The ratio of each material is determined so that concrete can be obtained economically.

In order to briefly examine the sequence of concrete mixing design, first, set the target quality items and target values, select the conditions and materials of the planned blending, and consider the required performance of durability and watertightness by data or test. Determine the binder cost, and calculate the unit quantity, unit cement amount, unit residual aggregate amount, unit coarse aggregate amount, admixture amount and the like sequentially. The test formulation is performed using the compound obtained as described above, and the final amount is determined by calibrating the unit amount of each material with reference to the result. Here, the water-binder ratio means the weight ratio of water to the binder.

Mix design of the concrete is the amount the amount of each of these materials is the process of estimating the amount of the materials used to make the concrete 1m ³ units (e.g., unit water (W), the unit cement amount of (C), the unit coarse goljaeryang (G), unit residual aggregate (S)).

When the design reference strength of the concrete structure is determined, the compounding strength is calculated accordingly. The compounding strength is a premium strength considering the standard deviation of the design reference strength and the concrete strength.

The water-binding ratio is determined so that the structure is mechanically safe and has the required strength, durability, and watertightness. First, the water-binding ratio that can satisfy the compounding strength is determined and whether the value can ensure durability and watertightness. Check and decide.

When water is mixed in concrete, it has a bad effect on dry shrinkage, bleeding and settling, durability, etc. of concrete, while improving the mobility of concrete. Therefore, the goal of calculating the unit quantity should be to reduce the unit quantity within the range to obtain the required workability.

Once the unit quantity is determined, the unit binder mass is calculated by the water-binding ratio.

The maximum size of coarse aggregate is selected in consideration of the type of structure, the minimum size of members, the rebar spacing, etc., and the maximum size of coarse aggregate is selected within the range where workability suitable for the work is obtained and there is no problem in strength, durability, watertightness, etc.

The unit coarse aggregate amount is determined based on the standard value of the apparent volume of unit coarse aggregate.

The concrete slump should be selected as small as possible within the range suitable for the working machine or work method such as a vibrator.

The calculation of air volume depends on the maximum size of the coarse aggregate. The larger the size, the smaller the air volume. The standard specification for building construction defines the air volume range.

Fine aggregate ratio (S / a = S / (G + S)) means the ratio of fine aggregate volume to total aggregate volume. The most expensive of the concrete materials is cement. Therefore, the fine aggregate ratio (S / a) is selected so that the amount of cement paste to the minimum within the range to obtain a suitable workability of concrete.

The test formulation is performed using the compound obtained as described above, and the final amount is determined by calibrating the unit amount of each material with reference to the result.

Hereinafter, embodiments of the high-strength concrete composition for preventing explosion according to the present invention will be described in detail.

The present invention is a composition for high-strength concrete containing 15 to 40 parts by weight of water and 0.5 to 4.0 parts by weight of a chemical admixture with respect to 100 parts by weight of the binder including 40 to 95% by weight of cement and 5 to 60% by weight of admixtures. The composition further includes an organic synthetic fiber, the content of the organic synthetic fiber is to be contained so that the content of 0.01 to 5.0 kg per m ^{3 of the} composition for concrete.

The present invention can prevent the bursting phenomenon by absorbing the water vapor pressure inside the concrete structure by melting the organic synthetic fibers in the concrete during the fire, and can increase the residual strength by increasing the binding force of the concrete structure.

High-strength concrete is manufactured to have great compressive strength and good durability, and in order to satisfy this performance, the internal structure of the concrete structure has a very dense structure. Such a compact structure prevents the release of water vapor pressure generated inside the concrete during a fire, and when the tensile strength of the concrete of water vapor pressure is exceeded, the concrete peels off and falls off with a heavy explosion. Therefore, in the present invention, a space formed by incorporating organic synthetic fibers having low heat resistance into concrete and melting and combusting the organic synthetic fibers due to a high temperature during a fire may absorb water vapor pressure inside the concrete structure to prevent explosion.

In the present invention, the binder has a cohesive force or an adhesive force and is a material used to bond materials, and cement also belongs to this. On the other hand, it is possible to improve the concrete properties by using the admixture as part of the binder together with the cement. "Mixed material" refers to a mixed material that has a high amount of use and needs to consider its own volume in the formulation design.However, it is distinguished from "chemical admixture" which is a mixed material in which the volume is relatively small and its volume can be ignored in the design. do.

In addition, the content of water is determined according to the water-bonding material ratio for expressing high strength concrete with a design strength of 50 MPa or more. In the composition for high-strength concrete for explosion prevention, 15 to 40 parts by weight of water is used for 100 parts by weight of the binder. .

If the content of water is less than 15 parts by weight, the workability is worsened, the workability is lowered, and if it exceeds 40 parts by weight, there is a problem in high strength expression. In general, in order to express high-strength concrete, it has a low water-binding ratio, but in the present invention, it is possible to easily secure workability with a relatively high water-binding ratio.

When the water-binding ratio is determined and the unit quantity is determined within the range in which required laborability can be secured, the binding mass is calculated. In the present invention, the binder is composed of cement and a mixed material, and the amount of the mixed material in the calculated amount of the binder is 5 to 60% by weight, and the remainder is cement.

These admixtures improve the fluidity and workability of the concrete and are filled in the voids between the cement particles to condense the structure of the concrete to improve the performance of the concrete. When the amount of admixture is 5% by weight or more, the desired strength can be obtained due to the void filling effect, and this synergy can be expected until 60% by weight.

As the admixture, fly ash, blast furnace slag, silica fume, polymer and pozzolane, metakaolin and the like can be used. Such admixtures may improve the watertightness of the concrete to enhance strength, or improve the performance of concrete such as the fire resistance of the concrete.

In the present invention, the chemical admixture is used for the purpose of improving the properties of concrete, workability, bleeding, setting time, change of length, durability, suppression of hydration heat and the like. Such chemical admixtures may be used AE agents, water reducing agents, AE water reducing agents, fluidizing agents, accelerators and the like. In addition, various chemical admixtures apparent to those skilled in the art may be used according to the purpose of improving the properties of concrete.

These chemical admixtures may be incorporated alone or in combination, depending on the purpose of improving the properties of the concrete, to be incorporated in 0.5 to 4.0 parts by weight based on 100 parts by weight of the binder. When the amount of miscible admixture is 0.5 parts by weight or more with respect to 100 parts by weight of the binder, it is possible to secure sufficient fluidity in the concrete to obtain a predetermined workability, and to be less than 4.0 parts by weight to limit the fluidity to prevent aggregate separation, and The strength of concrete can be secured.

In the present invention, the organic synthetic fibers can be incorporated into the concrete to prevent the explosion of the concrete in the event of fire and improve the strength of the concrete. Organic synthetic fiber is melted in case of fire and absorbs water vapor pressure inside the concrete structure to prevent it from collapsing. In general, it is uniformly dispersed in concrete to improve the strength by increasing the bonding strength of concrete.

The organic synthetic fibers may be mixed with 0.01 to 5.0kg per 1m ³ of concrete in the concrete according to the unit weight of the formulation of the concrete (kg / m ^3). May exhibit the case of fire by incorporating the amount of the organic synthetic fibers in concrete 1m ³ or more per 0.01kg explosion reducing effect it can be secured by more than a predetermined level by the strength of the concrete to less than 5.0kg. In general, as the strength of high-strength concrete increases, the unit weight of the concrete also increases, and accordingly, the amount of organic synthetic fibers mixed into the concrete may increase according to the increase in the unit weight of the concrete.

As the organic synthetic fiber, olefin fiber including polyethylene, polyamide fiber including nylon, polyacrylic fiber, polyester fiber, polypropylene fiber and polyvinyl alcohol fiber may be used.

Organic synthetic fibers are melted and combusted when a fire occurs to form a predetermined void in concrete, so the ratio of fiber length divided by diameter is 10 to 10,000, and starts to melt at 150 degrees Celsius or higher and then at 300 degrees Celsius or higher. The weight residual ratio is preferably 20% or less. Here, the weight residual ratio means a percentage obtained by dividing the weight of the organic synthetic fiber remaining after the fire by the weight before the fire.

Even when only organic synthetic fibers are mixed into the concrete, the concrete structure can maintain a predetermined strength even if a fire occurs due to remaining fire without being completely burned at about 300 degrees Celsius.

On the other hand, according to an embodiment of the present invention, the composition for preventing high-strength concrete may further comprise 0.05 to 5.0% by weight of steel fibers relative to the weight of the concrete.

Recently, as the structure using high strength concrete increases, the fire resistance performance standard of high strength concrete is strengthened. The recently strengthened fire resistance performance standard stipulates that the temperature of cast iron in columns and beams should be below 538 degrees Celsius and up to 649 degrees Celsius for the time specified in the performance criteria. In order to effectively prevent the explosion of high-strength concrete, a space for absorbing water vapor pressure must be provided in the concrete while the organic synthetic fibers are melted and burned. The above fireproof standards are satisfied in the process of melting and burning the organic synthetic fibers. If possible, steel fibers may be incorporated into the concrete to control the temperature inside the concrete. That is, by mixing the steel fibers in the production of high-strength concrete for explosion prevention, the steel fibers in the concrete absorb the heat energy due to the fire and uniformly distribute the temperature inside the concrete to lower the temperature in the concrete, through which the temperature of the rebar Temperature control inside the concrete is possible to meet the fire resistance standard. In addition, such steel fibers mixed in the concrete can increase the cohesion of the concrete structure in the event of a fire to increase the remaining strength to prevent the collapse of the structure.

As described above, in the present invention, steel fibers may be mixed as necessary to increase the binding force of the concrete to maintain the strength of the concrete. Such steel fibers improve the strength of concrete during the manufacture of concrete and maintain the binding force of the concrete even in the event of a fire, thereby increasing the residual compressive strength ratio of the concrete. In addition, the steel fiber can improve the resistance to cracking and impact resistance when incorporated into concrete. Here, the residual compressive strength ratio of concrete is a percentage obtained by dividing the compressive strength measured after the fire by the design strength before the fire to estimate the safety of the concrete in the event of a fire.

The amount of steel fiber mixed is 0.05% by weight or more with respect to the weight of concrete, so that the residual compressive strength required in the event of a fire and the temperature control effect inside the concrete can be obtained, and by setting it to 5.0% by weight or less, the steel fiber is uniformly dispersed in the concrete. The performance of concrete can be secured by preventing voids from increasing in concrete.

The shape ratio of the steel fiber is related to the tensile strength and the bending strength of the concrete, and the steel fiber having the shape ratio of 2 to 5,000 is mixed and used in the concrete. By maintaining the strength of the concrete by securing the binding force with the concrete by setting the shape ratio of the steel fiber to 2 or more, the fiber-balling of the steel fiber can be prevented by setting it to 5,000 or less.

In the composition for high-strength concrete according to the present invention, it is possible to prepare high-strength concrete by mixing only organic synthetic fibers or to prepare high-strength concrete by mixing steel fibers together with organic synthetic fibers. When the organic synthetic fibers and the steel fibers are mixed together, the ratio of the steel fibers to the organic synthetic fibers may be 1: 0.1 to 10 by weight.

On the other hand, when mixing the glass synthetic fiber or steel fiber as described above in the concrete to prevent the entanglement between the fibers to be uniformly dispersed in the concrete can be exhibited the properties after the concrete is solidified. To this end, 0.1 to 5 parts by weight of the fiber dispersant may be further added to 100 parts by weight of the binder.

The present invention will be described through the following examples and comparative examples. However, the following examples are only for illustrating the present invention, and the present invention is not limited thereto.

(Comparative Example 1)

According to the mixing ratio of Table 1 below, the test specimens were prepared by mixing concrete with a mixing strength of 60 MPa without mixing fly ash (F / A) and silica fume (S / F).

(Comparative Example 2)

According to the mixing ratio of Table 1 below, the fly ash (F / A) was mixed to prepare a specimen by mixing the concrete of the mixing strength of 60MPa.

(Comparative Example 3)

According to the compounding ratio of Table 1 below, the specimen was prepared by the concrete mixture of the compounding strength of 80MPa.

(Comparative Example 4)

According to the weight mix ratio of Table 1 below, the specimen was prepared by the concrete mix of the mixing strength of 100MPa.

Table 1.

 (Examples 1 to 4)

According to Table 2 below, 0.5 kg / m ^{3 of} organic synthetic fibers, 1.67 wt% of steel fibers, a chemical admixture, and a fiber dispersant were mixed and stirred in the same formulation as Comparative Examples 1 to 4, respectively, to prepare specimens. . As the organic synthetic fiber, polypropylene fiber was mixed. Here, the unit weight of the concrete is 2,350kg / m ³ , the unit weight of the steel fiber is considered to be 7,850kg / m ³ .

(Examples 5 to 8)

According to Table 2 below, 0.5 kg / m ^{3 of} organic synthetic fibers, 3.34 wt% of steel fibers, and a chemical admixture were mixed and stirred in the same formulations as Comparative Examples 1 to 4, respectively, to prepare specimens. As the organic synthetic fiber, polypropylene fiber was mixed. Here, the unit weight of the concrete is 2,350kg / m ³ , the unit weight of the steel fiber is considered to be 7,850kg / m ³ .

 (Examples 9 to 12)

According to Table 2 below, in the same formulation as Comparative Examples 1 to 4 above, 1.0 kg / m ^{3 of} organic synthetic fibers, 1.67 wt% of steel fibers, chemical admixtures and fiber dispersants were mixed and stirred to prepare specimens. . As the organic synthetic fiber, polypropylene fiber was mixed. Here, the unit weight of the concrete is 2,350kg / m ³ , the unit weight of the steel fiber is considered to be 7,850kg / m ³ .

(Examples 13 to 16)

According to Table 2 below, for each of the same formulation as Comparative Examples 1 to 4 above, 1.0 kg / m ^{3 of} organic synthetic fibers, 3.34 wt% of steel fibers, and chemical admixtures were mixed and stirred to prepare specimens. As the organic synthetic fiber, polypropylene fiber was mixed. Here, the unit weight of the concrete is 2,350kg / m ³ , the unit weight of the steel fiber is considered to be 7,850kg / m ³ .

Table 2.

division Polypropylene Fiber (kg / m ³ ) Steel fiber (wt%) Examples 1-4 0.5 1.67 Examples 5-8 0.5 3.34 Examples 9-12 1.0 1.67 Examples 13-16 1.0 3.34

Experimental Example 1

Slump and air volume experiments were performed on the concrete blended using the composition for the non-hardened high-strength concrete of Comparative Examples 1 to 4, and the compressive strength after heating and the compressive strength after heating were measured for 28 days. The results are shown in Table 3.

In the measurement method of the physical properties of Experimental Examples 1 to 5, the slump is the test method of slump flow of unconsolidated concrete of KS F 2594, the slump test method of concrete of KS F 2402, and the amount of air is not hardened by KS F 2421 pressure method. The air volume test method and the compressive strength of concrete were measured according to the test method of compressive strength of KS F 2405 concrete. In addition, the occurrence of the explosion was measured according to the fire resistance test method of the building member of KS F 2257-1-7.

Table 3.

Test Items unit Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 slump cm 23.5 23.0 23.0 23.0 Air volume % 4.0 4.0 4.4 4.3 Compressive Strength (28 Days) MPa 60.9 62.3 83.4 101.9 Heat test compressive strength MPa 44.5 44.3 40.9 40.4 Explosion O / X O O O O

As can be seen in Table 3, Comparative Examples 1 to 4 all exhibited proper fluidity when slumped to 23 cm or more. In addition, all of Comparative Examples 1 to 4 exceeded the target compounding strength. On the other hand, in Comparative Examples 1 to 4 it can be seen that the explosion occurs in the concrete during heating.

Experimental Example 2

The concrete blended using the composition for the non-hardened high-strength concrete of Examples 1 to 4 was subjected to a slump and air volume experiment immediately after blending, and the compressive strength after 28 days of age and the compressive strength after heating were measured. The results are shown in Table 4.

Table 4.

Test Items unit Example 1 Example 2 Example 3 Example 4 slump cm 23.0 24.0 23.0 23.0 Air volume % 4.2 3.8 4.3 4.1 Compressive Strength (28 Days) MPa 59.6 60.1 81.7 102.4 Compressive strength after heating test MPa 57.1 57.4 67.7 70.5 Explosion O / X X X X X liquidity good good good good

As can be seen in Table 4, Examples 1 to 4 all exhibited proper fluidity when slumped to 23 cm or more. In addition, in Example 1, the compressive strength is 59.6 MPa, which is lower than the compounding strength, but the difference is 0.4 MPa, which is negligible, and Examples 2 to 4 exceed the target compounding strength. On the other hand, all of Examples 1 to 4 did not cause explosion in the concrete during heating, and compared with Comparative Examples 1 to 4 it can be seen that the compressive strength after the heating test is large, the performance is excellent when a fire occurs.

Experimental Example 3

The slump and air volume experiment was performed immediately after the mixing of the concrete blended using the composition for the high strength concrete of Example 5 to Example 8, and the compressive strength of the 28-day-old age and the compressive strength after heating were measured. The results are shown in Table 5.

Table 5.

Test Items unit Example 5 Example 6 Example 7 Example 8 slump cm 23.5 23.0 22.5 23.5 Air volume % 4.0 3.9 4.6 4.2 Compressive Strength (28 Days) MPa 60.9 62.3 83.4 104.7 Compressive strength after heating test MPa 56.4 58.4 63.9 62.4 Explosion O / X X X X X liquidity good good good good

As can be seen in Table 5, Examples 5 to 8 all exhibited proper fluidity when slumped to 22 cm or more. In addition, in Examples 5 to 8, each exceeds the target compounding strength.

On the other hand, all of Examples 5 to 8 did not cause explosion in the concrete during heating, and compared with Comparative Examples 1 to 4 it can be seen that the excellent compressive strength after the heating test, the performance is excellent when a fire occurs.

Experimental Example 4

The concrete blended using the composition for the non-hardened high strength concrete of Examples 9 to 12 was carried out after blending, slump and air volume experiment, and after hardening, the compressive strength after 28 days of age and the compressive strength after heating were measured. The results are shown in Table 6.

Table 6.

Test Items unit Example 9 Example 10 Example 11 Example 12 slump Cm 23.5 23.5 22.5 22.5 Air volume % 3.9 3.8 4.5 4.4 Compressive Strength (28 Days) MPa 58.9 60.3 81.7 101.9 Compressive strength after heating test MPa 54.4 59.9 64.2 69.2 Explosion O / X X X X X liquidity good good good good

As can be seen in Table 6, Example 9 to Example 12 all exhibited proper fluidity when pouring slump 22 cm or more. In Example 9, the compressive strength was 58.9 MPa, which was lower than the compounding strength, but the difference was negligible as 1.1 MPa. Examples 10 to 12 exceeded the target compounding strength.

On the other hand, all of Examples 9 to 12 did not cause explosion in the concrete during heating, compared with Comparative Examples 1 to 4 it can be seen that the performance is excellent when the fire occurs due to the high compressive strength after the heating test.

Experimental Example 5

The concrete blended using the composition for the non-hardened high-strength concrete of Examples 13 to 16 was subjected to a slump and air volume experiment after blending, and the compressive strength after 28 days of age and the compressive strength after heating were measured. The results are shown in Table 7.

Table 7.

Test Items unit Example 13 Example 14 Example 15 Example 16 slump cm 23.0 23.5 23.0 23.0 Air volume % 3.9 3.7 4.3 4.5 Compressive Strength (28 Days) MPa 57.1 57.1 78.8 101.1 Compressive strength after heating test MPa 49.8 53.0 45.9 61.4 Explosion O / X X X X X liquidity good good good good

As can be seen in Table 7, Examples 13 to 16 all exhibited proper fluidity when slumped to 23 cm or more. Examples 13, 14, and 15 had compressive strengths of 57.1 MPa, 57.1 MPa, and 78.8 MPa, but the difference was negligible as 2.9 MPa, 2.9 MPa, and 1.2 MPa, and Example 16 exceeded the target compounding strength. Doing.

On the other hand, all of Examples 13 to 16 did not cause explosion in the concrete during heating, compared with Comparative Examples 1 to 4 it can be seen that the compression strength after the heating test is large, the performance is excellent when the fire occurs.

Many embodiments other than the above-described embodiments are within the scope of the claims of the present invention.

Claims (9)

For 100 parts by weight of a binder comprising 40 to 95% by weight cement and 5 to 60% by weight admixture, 15 to 40 parts by weight of water, and Chemical admixture is a composition for high strength concrete containing 0.5 to 4.0 parts by weight, The composition for concrete further comprises an organic synthetic fiber, wherein the content of the organic synthetic fiber is contained in an explosion-resistant high-strength concrete composition to be 0.01 to 5.0 kg per 1 m ^{3 of the} concrete composition. The method of claim 1, A composition for preventing high-strength concrete further comprising 0.05 to 5.0% by weight of steel fibers relative to the weight of the concrete. The method of claim 2, The steel fiber is a composition for preventing high-strength concrete, characterized in that the shape ratio of 2 to 5,000. The method of claim 2, The organic synthetic fiber and the steel fiber is a composition for preventing high-strength concrete, characterized in that mixed in a weight ratio of 1: 0.1 to 1:10. The method of claim 1, The organic synthetic fiber is at least one selected from the group consisting of olefin fiber including polyethylene, polyamide fiber including nylon, polyacryl fiber, polyester fiber, polypropylene fiber and polyvinyl alcohol fiber High strength concrete for prevention. The method of claim 1, The organic synthetic fiber has a shape ratio of 10 to 10,000, starting to melt at 150 degrees Celsius, the residual weight of the high-strength concrete composition for explosion prevention, characterized in that the weight residual ratio is 0 to 20% at 300 degrees Celsius. The method of claim 1, Composition for preventing high-strength concrete further comprises 0.1 to 5 parts by weight of the fiber dispersant based on 100 parts by weight of the binder. The method of claim 1, The admixture is a fly ash, blast furnace slag, silica fume, polymer, pozzolanic and metakaolin for at least one selected from the group consisting of meta kaolin composition for preventing high-strength concrete. The method of claim 1, The chemical admixture is a composition for preventing high-strength concrete, characterized in that it comprises at least one selected from the group consisting of AE agent, water reducing agent, AE water reducing agent, fluidizing agent, and accelerator.