WO2001085641A1 - Concrete being resistant to rupture - Google Patents

Concrete being resistant to rupture Download PDF

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Publication number
WO2001085641A1
WO2001085641A1 PCT/JP2000/002972 JP0002972W WO0185641A1 WO 2001085641 A1 WO2001085641 A1 WO 2001085641A1 JP 0002972 W JP0002972 W JP 0002972W WO 0185641 A1 WO0185641 A1 WO 0185641A1
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WO
WIPO (PCT)
Prior art keywords
explosion
fiber
fibers
concrete
resistant concrete
Prior art date
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PCT/JP2000/002972
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French (fr)
Japanese (ja)
Inventor
Toshio Yonezawa
Akio Kodaira
Hideo Fujinaka
Kenrou Mitsui
Nobuyuki Yamazaki
Akira Nishida
Takeshi Morita
Original Assignee
Takenaka Corporation
Shimizu Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Takenaka Corporation, Shimizu Corporation filed Critical Takenaka Corporation
Priority to DE10085471T priority Critical patent/DE10085471T1/en
Priority to GB0226053A priority patent/GB2379928A/en
Priority to PCT/JP2000/002972 priority patent/WO2001085641A1/en
Priority to FR0005956A priority patent/FR2808795A1/en
Publication of WO2001085641A1 publication Critical patent/WO2001085641A1/en
Priority to NO20025314A priority patent/NO20025314D0/en
Priority to DK200201717A priority patent/DK200201717A/en
Priority to SE0203314A priority patent/SE0203314L/en

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B16/00—Use of organic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of organic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
    • C04B16/04—Macromolecular compounds
    • C04B16/06—Macromolecular compounds fibrous
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/20—Resistance against chemical, physical or biological attack
    • C04B2111/28—Fire resistance, i.e. materials resistant to accidental fires or high temperatures
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
    • C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
    • C04B2201/52—High compression strength concretes, i.e. with a compression strength higher than about 55 N/mm2, e.g. reactive powder concrete [RPC]

Definitions

  • the present invention relates to concrete excellent in explosion resistance in a fire that can be used for structures that may be subject to fire, such as buildings and tunnels. Background art
  • Higher-strength concrete can be obtained by reducing the ratio of water to the binder in concrete, that is, cement, slag, fly ash, silica film, and other materials that undergo hydration in concrete.
  • Increasing the strength of concrete can benefit in various ways, such as reducing the cross-sectional dimensions of building columns and increasing the height of buildings.
  • the surface concrete can easily explode due to water vapor pressure, thermal stress, etc. in a high-temperature environment such as a fire, which may cause various problems. It is known that there is.
  • the following technologies are known to suppress the explosion of buildings using such high-strength concrete.
  • Japanese Patent Publication No. 57-201 126 It describes acetate of 2 O mm, thickness of 1 to 25 denier, or an extruded plate containing 0.5 to 2.0% of rayon fiber by weight of cement asbestos. There is disclosure that a hole is formed and explosion is prevented by allowing water vapor to escape from this portion.
  • Japanese Patent Laid-Open No. No. 1284 describes a method to prevent explosion by mixing hollow polypropylene fibers and letting steam escape from the pores of the fibers.
  • Japanese Patent Publication No. Sho 62-121197 Describes a method for preventing explosion by securing 1 to 5 ⁇ pores in an asbestos cement having a porosity of 30 to 60% by mixing pearlite or pulp to 10% or more of the voids. ing.
  • the method of mixing filler such as fiber into concrete is suitable for high-strength concrete. Although it can be used, mixing an effective amount that has the effect of suppressing explosion will reduce the fluidity of concrete, making it difficult to cast into the formwork at the construction site.
  • high-strength concrete achieves high strength by reducing the ratio of the amount of water to binders such as cement. As the ratio of water binder decreases, the plastic viscosity increases and the workability deteriorates.Therefore, the development of a surfactant as a dispersant for high-strength cement and the use of ultrafine particles with vitreous silica force The required fluidity is secured by using silica fume. Therefore, it is not possible to mix a large amount of fibers with the aim of ensuring resistance to explosion, and to reduce the flowability.
  • the inventors of the present invention have focused on the fact that the technique of mixing fibers made of an organic material is effective in preventing explosion and has high economical efficiency. After examining various effective means applied to high-strength concrete, the present invention was completed.
  • the present inventors examined conventionally known organic fiber materials and found that there was a great difference in the explosion prevention effect due to the difference in the amount of evaporation when the fiber was heated to 500 ° C. Based on the results, the present inventors have found that the above object can be achieved by using a specific material that can form voids efficiently under high temperature conditions.
  • the explosion-resistant concrete of the present invention is made of an organic material having a weight retention of 30% or less when heated to 500 ° C., having a diameter of 5 to 200 ⁇ 111 and a length of 5 to 40 mm.
  • the organic fiber of the present invention is characterized by containing from 0.02 to 0.3% by volume of the organic fiber and having a water binder ratio of 35% or less.
  • Figures 1A to 1C are model diagrams showing effective concrete columns and fiber holes for explosion resistance studies.
  • Figure 2 is a graph showing the relationship between the diameter of the effective concrete column and the amount of fiber mixed into the concrete for each fiber diameter.
  • Figure 3 is a graph showing the relationship between the fiber mixing ratio and fluidity of explosion-resistant concrete mixed with organic fibers.
  • Figure 4 is a graph showing the relationship between the weight loss rate of explosion-resistant concrete containing organic fibers and the fiber mixing rate.
  • FIG. 5 is a graph of a standard heating curve used for heating a test piece in the fire resistance test of 7 of the following Examples. BEST MODE FOR CARRYING OUT THE INVENTION
  • an organic fiber to be added to concrete a fiber formed of an organic material having a weight retention of 30% or less when heated to 500 ° C. is used.
  • an organic material having a low melting point is considered to be preferable.
  • the present inventors have studied and found that an organic material does not necessarily exhibit excellent explosion resistance simply by having a low melting point, and explosion resistance is related to the residual weight ratio when heated to 500 ° C. I found something to do.
  • the weight retention rate of various organic fibers when heated at 500 ° C is from 10% to 20%.
  • the residual weight ratio at the time of heating at 500 ° C. exceeds 30%, the formation of water vapor escape holes due to the evaporation of the fibers is insufficient, and the explosion resistance decreases.
  • the residual weight ratio at the time of heating to 500 ° C is 30% or less, large holes having a volume equivalent to the fiber volume before evaporation are formed due to the evaporation of the fibers, and the holes escape the water vapor. Since it functions well as a hole, it exhibits favorable explosion resistance.
  • each fiber present in the concrete matrix quickly forms effective pores after heating, the amount of fiber used can be reduced. Since the amount of fiber used is small, the effect on the fluidity of concrete is small, and high-strength concrete with good workability can be economically realized.
  • organic materials constituting these organic fibers natural organic materials, semi-synthetic organic materials, or synthetic organic materials that are decomposed or melted by heating in a fire to cause a sharp decrease in volume are used. Used.
  • the residual weight ratio of polypropylene and polyvinyl alcohol is 1 4% and 18%, which meet the requirements of the present invention.
  • polyvinyl chloride and acrylic fibers are not suitable as the fibers of the present invention because the residual weight ratio exceeds 30%.
  • the natural organic material, the semi-synthetic organic material, or the synthetic organic material constituting the organic fiber of the present invention may be melted or evaporated by heating to cause a rapid decrease in volume, In particular, the residual weight ratio when heated to 500 ° C must be 30% or less. Therefore, it is necessary to select from known synthetic resins, natural fibers, synthetic fibers, semi-synthetic fibers and the like in consideration of the above conditions.
  • Preferred examples of the material include a polypropylene-based material, a polyvinyl alcohol-based material, and a vinylidene-based material.
  • the shape of the organic fiber is directly related to the shape of the pore formed by evaporation of the organic fiber.
  • the effect of the pores that is, the effect of the water vapor vent hole, which provides resistance to explosion during heating, differs depending on the fiber diameter, the amount of fiber mixed in, and the concrete strength, etc. studied here.
  • the state of the fibers (diameter d f ) dispersed in the concrete is modeled as a state in which the fibers are uniformly covered with the cover concrete and distributed in parallel as shown in Fig. 1A.
  • water vapor from a cylindrical concrete part (hereinafter referred to as an “effective concrete column”) approximated by a hexagon as shown in Fig. 1B escapes. become.
  • This movement of water vapor is indicated by an arrow in FIG. 1C.
  • the pores formed by the fibers allow water vapor from the area of the cover concrete to escape from the holes.
  • Figure 2 is a graph showing the relationship between the effective concrete column diameter d c (mm) and the amount of fiber mixed into the concrete V f (volume%) for each fiber diameter.
  • Figure From Fig. 2 it can be seen that the diameter of the effective concrete column decreases as the fiber mixing ratio increases, and that the diameter of the effective concrete column decreases as the fiber diameter decreases.
  • the smaller the diameter of the effective concrete pillar the narrower the area where water vapor is collected in one fiber hole, and thus the more effective the explosion prevention effect. It will be big. In other words, it is clear that the higher the fiber mixing ratio and the smaller the fiber diameter, the more effective it is in preventing explosion.
  • the rate at which water vapor is collected in one fiber hole depends on the strength of the concrete, that is, the density of the tissue. Therefore, the diameter of the effective concrete column required to prevent explosion decreases as the strength increases.
  • the present inventors conducted a loading heating experiment on a reinforced concrete column. For 3 hours, the amount of fiber required to maintain 1/3 of the strength (normal maximum value of long-term load) is determined by using polypropylene fibers with a fiber diameter of 20 m and concrete with different compressive strength. And evaluated.
  • the compressive strength of concrete is 800 kgf / cm 2
  • the necessary fiber content is 0.01 to 0.02% by volume
  • the compressive strength of concrete is 1 000 kgf Zcm 2
  • the diameter of the effective concrete column required explosion prevention, 2. 0 2. about 5 mm in case the compressive strength of the concrete is SOO kg fZcm 2, compression of the concrete
  • the strength is l OOO kgf Zcm 2 , it is estimated to be around 1. Omm.
  • the model diagram in FIG. 1 A to FIG 1 C It is necessary to set the diameter (d c ) of the effective concrete column shown to be within the range of 2. Omm or less.
  • the fiber diameter is between 5 and 200 m. Less than 5 ⁇ ⁇ When it exceeds 200 tm, it is difficult to exhibit sufficient explosion resistance to high-density concrete.
  • the length of the fiber is preferably 5 to 4 O mm. If it is less than 5 mm, the effect of preventing explosion will be insufficient, and if the fiber length exceeds 4 Omm, the dispersion of fibers will be poor and it will be difficult to obtain uniform concrete.
  • These organic fibers are mixed into concrete so that they are substantially uniformly dispersed without agglomeration. These organic fibers are not added all at once, but rather in small portions continuously or in small portions during the kneading phase of the concrete material using a mixing device. It is preferably added to the material.
  • 0 mixed amount of fiber needed for explosion prevention of high-strength concrete Ichiboku is the volume of the concrete. 0 2 to 0.3 volume 0/0, i.e., 1 111 3 per Li 0. 2 with 3 liters is there.
  • the organic fiber of the present invention occur quickly evaporates at high temperatures, even in the case of using the fiber easily forms an effective air gap, 0. 0 2 volume% Sunawachi 0. Explosion prevention is less than 2? Zm 3 If the effect is insufficient and 0.3% by volume, that is, 3 liters Zm 3 or more is mixed, the fluidity of the concrete is reduced, and neither is preferable.
  • the organic fiber according to the present invention is flexible, and has little effect on its fluidity even when dispersed in concrete. By dispersing this fiber into concrete as a filler, water vapor generated in the event of a fire in the event of a fire escapes to the outside, effectively preventing explosion of the concrete.
  • Concrete water binder ratio In the case of ordinary concrete exceeding 35%, the effect of explosion occurring in concrete at the time of fire is a level that does not cause a problem.
  • the present invention can be said to be particularly useful when applied to high-strength concrete having a water binder ratio of 35% or less.
  • Fine aggregate mountain sand (specific gravity 2.55, water absorption 1.54%) and hard sandstone
  • Admixture powdered silica film (specific gravity 2.2, specific surface area 14m 2 Zg,
  • Admixture Polycarboxylate-based high-performance A E water reducer (trade name: Tupole HP-11, Takemoto Yushi Co., Ltd.)
  • Organic fiber A polypropylene fiber having a diameter of 20 ⁇ , a length of 19mm, and a weight retention rate of 14% when heated to 500 ° C was used.
  • the organic fibers were mixed in the concrete prepared above under the conditions of 0.05% by volume, 0.10% by volume, 0.20% by volume, and 0.30% by volume.
  • a 100 litter pan type forced remixer was used. The amount of each kneading was 60 liters. After sand, cement, and silica foam were kneaded for 15 seconds, water and an admixture were added, kneaded and mixed for 1 minute, and then coarse aggregate was added. The mixing time after the addition of the coarse aggregate was 2 minutes, and the fibers were mixed during the first 30 seconds.
  • the concrete containing 0.05% by volume of organic fiber was used in Example 1, the concrete containing 0.1% by volume was used in Example 2, and the concrete containing 0.2% by volume was used in Examples 3 and 0. . 3% by volume was used as Example 4.
  • Example 1 the fiber to be mixed was replaced with the organic fiber, and an acrylic fiber having a diameter of 17 m, a length of 20 mm, and a residual weight of 76% when heated to 500 ° C was used. Concrete was produced in the same manner as in Example 1 except that the amounts were 0%, 0.05% by volume, 0.1% by volume, 0.2% by volume, and 0.3% by volume. 2 to 6. Similarly to Example 1, the concretes of Comparative Examples 2 to 6 were subjected to the (6) concrete fluidity test and (7) fire resistance test. The results are shown in Table 2. Table 2
  • the present invention has an effect that explosion can be effectively suppressed without lowering fluidity, and an economical high-strength explosion-resistant concrete can be provided.

Abstract

A concrete being resistant to rupture, characterized in that it contains 0.02 to 0.3 vol % of an organic fiber comprising an organic material which shows a residual weight percentage of 30 % or less after a heat treatment at 500°C and having a diameter of 5 to 200 νm and a length of 5 to 40 mm, and has a ratio of water to binding materials of 35 % or less.

Description

明細書  Specification
耐爆裂性コンクリート 技術分野  Explosion-resistant concrete
本発明は建築物やトンネル等、 火災を受ける可能性のある構造物に使用可能 な、 火災時の耐爆裂性に優れたコンクリートに関する。 背景技術  The present invention relates to concrete excellent in explosion resistance in a fire that can be used for structures that may be subject to fire, such as buildings and tunnels. Background art
コンクリートにおける結合材、 即ち、 セメント、 スラグ、 フライアッシュ、 シリカフユ一ム等、 コンクリート中で水和反応する材料、 と水との比率を小さ くすると、 高強度のコンクリートが得られる。 コンクリートの強度を高くする ことにより、 建造物の柱の断面寸法の縮小、 建築物の高層化など、 さまざまの 点で利益を得ることが出来る。 しかしながら、 水の含有量を低下させてコンク リートを高強度化すると、 火災時等高温環境下で、 水蒸気圧や熱応力等により 表面のコンクリートが爆裂し易くなリ、 種々の問題を生ずる可能性のあること が知られている。 このような高強度コンクリートを用いた建築物の爆裂を抑制 するために、 次の技術が知られている。  Higher-strength concrete can be obtained by reducing the ratio of water to the binder in concrete, that is, cement, slag, fly ash, silica film, and other materials that undergo hydration in concrete. Increasing the strength of concrete can benefit in various ways, such as reducing the cross-sectional dimensions of building columns and increasing the height of buildings. However, if the water content is reduced to increase the strength of the concrete, the surface concrete can easily explode due to water vapor pressure, thermal stress, etc. in a high-temperature environment such as a fire, which may cause various problems. It is known that there is. The following technologies are known to suppress the explosion of buildings using such high-strength concrete.
特開平 9一 1 3 5 3 1号には柱の周囲の、 火災を直接受ける表面近傍に強度 の低いコンクリートを使用して爆裂を抑制するとともに、 中央部には高強度コ ンクリートを利用して、 外力と火災に対して高い抵抗性を保持する構造物が記 載されている。  In Japanese Patent Application Laid-Open No. 9-113531, low-strength concrete is used around pillars and in the vicinity of the surface directly subject to fire to suppress explosion, and high-strength concrete is used in the center. Structures that maintain high resistance to external forces and fire are described.
また、 構造体に用いるコンクリートそのものではないが、 建物の内外装用の パネルなどに使用する高強度の押出し成型板として、 例えば、 特公昭 5 7 _ 2 0 1 2 6号には、 長さ 5〜2 O mm、 太さ 1〜2 5デニールのアセテート、 ま たはレーヨン繊維をセメントアスベスト重量の 0 . 5〜2 . 0 %混入した押出 し成型板が記載され、 火災時に繊維が蒸発して細孔を形成し、 この部分から水 蒸気を逃すことにより爆裂を防止する旨の開示がある。 さらに、 特開昭 5 9— 1 2 8 4号には、 中空のポリプロピレン繊維を混入し、 この繊維の孔から蒸気 を逃すことにより、 爆裂を防止する方法が記載され、 同様に特公昭 6 2— 1 2 1 9 7号には、 パーライトやパルプを混合することにより、 空隙率 3 0〜 6 0 %のアスペストセメント中の 1〜 5 πιの細孔を空隙の 1 0 %以上確保し、 爆 裂を防止する方法が記載されている。 Although it is not concrete used for structures, it is a high-strength extruded plate used for interior and exterior panels of buildings.For example, Japanese Patent Publication No. 57-201 126 It describes acetate of 2 O mm, thickness of 1 to 25 denier, or an extruded plate containing 0.5 to 2.0% of rayon fiber by weight of cement asbestos. There is disclosure that a hole is formed and explosion is prevented by allowing water vapor to escape from this portion. Furthermore, Japanese Patent Laid-Open No. No. 1284 describes a method to prevent explosion by mixing hollow polypropylene fibers and letting steam escape from the pores of the fibers. Similarly, Japanese Patent Publication No. Sho 62-121197 Describes a method for preventing explosion by securing 1 to 5 πι pores in an asbestos cement having a porosity of 30 to 60% by mixing pearlite or pulp to 10% or more of the voids. ing.
これらは、 いずれもコンクリートの耐爆裂性にある程度の効果を有する。 し かし、 特開平 9— 1 3 5 3 1のように、 高強度コンクリート部材の表面に低強 度のコンクリートを使用する方法は、 建築物の柱等の断面積を必然的に大きく せざるを得ず、 高強度コンクリートを利用する効果を減じてしまうことになリ 、 さらに、 少なくとも二種類のコンクリートを使用することで、 複雑な施工法 となり、 著しくコストが高くなるという問題があった。  These all have some effect on the explosion resistance of concrete. However, the method of using low-strength concrete for the surface of high-strength concrete members, as disclosed in Japanese Patent Application Laid-Open No. 9-113531, inevitably increases the cross-sectional area of pillars and the like in buildings. However, the effect of using high-strength concrete is reduced, and the use of at least two types of concrete results in a complicated construction method and a significant increase in cost.
また、 特公昭 5 7 - 2 0 1 2 6号や特開昭 5 9 - 1 2 8 4号等のように、 コ ンクリートに繊維などの充填材を混入する方法は、 高強度のコンクリートに適 用可能であるが、 爆裂を抑制する効果がある有効量を混入するとコンクリート の流動性が低下し、 施工現場で型枠中に打設するのが困難になる。  In addition, the method of mixing filler such as fiber into concrete, such as Japanese Patent Publication No. 57-212 and Japanese Patent Publication No. 59-12884, is suitable for high-strength concrete. Although it can be used, mixing an effective amount that has the effect of suppressing explosion will reduce the fluidity of concrete, making it difficult to cast into the formwork at the construction site.
特公昭 6 2 - 1 2 1 9 7号のようにアスベストセメント中に空隙を確保する 技術を高強度コンクリートに適用した場合、 多量の空隙を形成することにより 必然的に強度が低下してしまい、 高強度コンクリートの本質的な目的が達成で きなくなる。  When the technology to secure voids in asbestos cement is applied to high-strength concrete as in Japanese Patent Publication No. 62-119, the strength is inevitably reduced by forming a large amount of voids. The essential purpose of high strength concrete cannot be achieved.
もともと、 高強度コンクリートは、 セメント等の結合材に対する水の量の比 率を小さくして高い強度を達成している。 水結合材比の低下とともに、 塑性粘 度が大きくなリ、 作業性が低下することから、 高強度セメント用の分散剤とし ての界面活性剤の開発や、 ガラス質シリ力の超微粒子であるシリカフュームの 利用等により所要の流動性を確保しているものである。 したがって、 爆裂に対 する抵抗性を確保する目的で繊維を多量に混入して、 流動性が低下することは Originally, high-strength concrete achieves high strength by reducing the ratio of the amount of water to binders such as cement. As the ratio of water binder decreases, the plastic viscosity increases and the workability deteriorates.Therefore, the development of a surfactant as a dispersant for high-strength cement and the use of ultrafine particles with vitreous silica force The required fluidity is secured by using silica fume. Therefore, it is not possible to mix a large amount of fibers with the aim of ensuring resistance to explosion, and to reduce the flowability.
、 実用上好ましくない。 繊維の混入が爆裂防止に有効であるとしても、 高強度 コンクリートの流動性の低下は最小限に抑制できなければならない。 上記のように高強度コンクリートの爆裂を防止しょうとする現状の技術は、 各々、 ある程度の効果を有する反面、 高強度コンクリートに適用した場合には 種々の課題を有している。 本発明は、 このような現状を考慮し、 流動性を低下 させることなく、 爆裂を抑制することができ、 経済性の高い高強度コンクリ一 トを提供するものである。 発明の開示 It is not preferable for practical use. Even if fiber incorporation is effective in preventing explosion, the reduction in fluidity of high-strength concrete must be minimized. The current technologies for preventing explosion of high-strength concrete as described above each have a certain effect, but have various problems when applied to high-strength concrete. The present invention has been made in view of such a current situation, and provides a high-strength concrete which can suppress explosion without lowering fluidity and has high economic efficiency. Disclosure of the invention
本願発明者らは、 上記問題に鑑みて、 有機材料からなる繊維を混入する技術 が爆裂防止に有効であり、 かつ、 経済性が高い点に着目し、 流動性の低下を抑 制し、 高強度コンクリートに適用する効果的な手段を種々検討のうえ、 本発明 を完成した。  In view of the above problems, the inventors of the present invention have focused on the fact that the technique of mixing fibers made of an organic material is effective in preventing explosion and has high economical efficiency. After examining various effective means applied to high-strength concrete, the present invention was completed.
繊維を混入した時の流動性の低下を抑制するためには、 少量の繊維で、 爆裂 を防止することが有効である。 すなわち、 爆裂防止効果の高い繊維を使うこと が有効である。 本発明者らは、 従来知られている有機繊維材料を検討し、 繊維 を 5 0 0 °Cに加熱した時の蒸発量の違いによって爆裂防止効果に大きな違いが あることを見出した。 その結果に基づき本発明者らは、 高温度条件下において 効率よく空隙を形成しうる特定の材料を用いることによリ前記目的を達成しう ることを見出した。  In order to suppress the decrease in fluidity when fibers are mixed, it is effective to prevent explosion with a small amount of fibers. In other words, it is effective to use fibers having a high explosion prevention effect. The present inventors examined conventionally known organic fiber materials and found that there was a great difference in the explosion prevention effect due to the difference in the amount of evaporation when the fiber was heated to 500 ° C. Based on the results, the present inventors have found that the above object can be achieved by using a specific material that can form voids efficiently under high temperature conditions.
本発明の耐爆裂性コンクリートは、 5 0 0 °Cに加熱した時の重量残存率が 3 0 %以下である有機材料よりなる、 直径5〜2 0 0 ^ 111、 長さ 5〜4 0 mmの 有機繊維を 0 . 0 2〜0 . 3容量％を含有し、 水結合材比が 3 5 %以下である ことを特徴とする。  The explosion-resistant concrete of the present invention is made of an organic material having a weight retention of 30% or less when heated to 500 ° C., having a diameter of 5 to 200 ^ 111 and a length of 5 to 40 mm. The organic fiber of the present invention is characterized by containing from 0.02 to 0.3% by volume of the organic fiber and having a water binder ratio of 35% or less.
5 0 0 °Cに加熱した時の重量残存率 （非蒸発量） が 3 0 %以下の、 重量残存 率が小さい有機材料からなる有機繊維を用いることにより、 繊維の添加量が少 量であっても速やかに減容して有効な空孔を形成しうるため、 コンクリートの 流動性を低下させない程度の有機繊維の添加量によっても有効な爆裂防止性を 達成しうる。 図面の簡単な説明 By using organic fibers made of an organic material having a low weight retention rate of less than 30% by weight retention (non-evaporation) when heated to 500 ° C, the amount of added fibers is small. Even though the volume can be quickly reduced to form effective voids, effective explosion prevention can be achieved even with the added amount of organic fibers that does not decrease the fluidity of concrete. BRIEF DESCRIPTION OF THE FIGURES
図 1 A〜図 1 Cは耐爆裂性検討のための有効コンクリ一ト柱と繊維孔を示 すモデル図である。  Figures 1A to 1C are model diagrams showing effective concrete columns and fiber holes for explosion resistance studies.
図 2は有効コンクリート柱の直径と繊維のコンクリート中への混入量との 関係を、 繊維の直径ごとに示したグラフである。  Figure 2 is a graph showing the relationship between the diameter of the effective concrete column and the amount of fiber mixed into the concrete for each fiber diameter.
図 3は有機繊維を混入した耐爆裂性コンクリートの繊維の混入率と流動性 の関係を示すグラフである。  Figure 3 is a graph showing the relationship between the fiber mixing ratio and fluidity of explosion-resistant concrete mixed with organic fibers.
図 4は有機繊維を混入した耐爆裂性コンクリ一トの重量減少率と繊維の混 入率の関係を示すグラフである。  Figure 4 is a graph showing the relationship between the weight loss rate of explosion-resistant concrete containing organic fibers and the fiber mixing rate.
図 5は下記実施例中 7の耐火試験において試験体を加熱する際に用いられ た標準加熱曲線グラフである。 発明を実施するための最良の形態  FIG. 5 is a graph of a standard heating curve used for heating a test piece in the fire resistance test of 7 of the following Examples. BEST MODE FOR CARRYING OUT THE INVENTION
本発明において、 コンクリートに添加する有機繊維としては、 5 0 0 °Cに加 熱した時の重量残存率が 3 0 %以下である有機材料により形成されたものが用 いられる。  In the present invention, as an organic fiber to be added to concrete, a fiber formed of an organic material having a weight retention of 30% or less when heated to 500 ° C. is used.
通常、 耐爆裂性コンクリートに加熱時に水蒸気を逃がして爆裂を防止するた めの空孔を形成する材料としては、 融点の低 、有機材料が好ましいとされてい る。 しかし本発明者らは検討の結果、 有機材料は単に融点が低いのみでは優れ た耐爆裂性を必ずしも発現しないこと、 耐爆裂性は 5 0 0 °Cに加熱した時の重 量残存率に関連することを見いだした。  Generally, as a material for forming pores for preventing explosion by releasing steam when heated in explosion-resistant concrete, an organic material having a low melting point is considered to be preferable. However, the present inventors have studied and found that an organic material does not necessarily exhibit excellent explosion resistance simply by having a low melting point, and explosion resistance is related to the residual weight ratio when heated to 500 ° C. I found something to do.
各種有機繊維の 5 0 0 °C加熱時の重量残存率には、 1 0〜2 0 %のものから The weight retention rate of various organic fibers when heated at 500 ° C is from 10% to 20%.
8 0 %程度のものまで、 各種ある。 重量残存率の大きい繊維を使用した場合に は、 火災時に、 繊維の蒸発によって形成される爆裂防止用のコンクリート中の 水蒸気の逃し穴が十分形成されないため、 爆裂防止に対する繊維の効果は、 大 きくそこなわれてしまう。 これに対して、 5 0 0 °Cに加熱した時の重量残存率 の小さい繊維は、 火災時によく蒸発し、 効果的に水蒸気の逃し穴を形成するこ とができるので、 少ない繊維で有効に爆裂を防止できることになる。 There are various types up to about 80%. When fibers with a high weight retention rate are used, the effect of the fibers on explosion prevention is significant because, in the event of a fire, water vapor escape holes in the concrete for preventing explosion formed by evaporation of the fibers are not sufficiently formed. I will be lost there. On the other hand, the residual weight ratio when heated to 500 ° C Smaller fibers evaporate well in a fire and can effectively form a water vapor vent, so fewer fibers can effectively prevent explosion.
5 0 0 °Cに加熱した時の重量残存率が 3 0 %を上回る場合には繊維の蒸発に よる水蒸気逃し穴の形成が不十分で耐爆裂性が低下する。 5 0 0 °Cに加熱した 時の重量残存率が 3 0 %以下の場合には、 繊維の蒸発により蒸発前の繊維体積 に匹敵する容積の大きな空孔が形成され、 その空孔が水蒸気逃し穴としてよく 機能するので、 好ましい耐爆裂性を発現する。  If the residual weight ratio at the time of heating at 500 ° C. exceeds 30%, the formation of water vapor escape holes due to the evaporation of the fibers is insufficient, and the explosion resistance decreases. When the residual weight ratio at the time of heating to 500 ° C is 30% or less, large holes having a volume equivalent to the fiber volume before evaporation are formed due to the evaporation of the fibers, and the holes escape the water vapor. Since it functions well as a hole, it exhibits favorable explosion resistance.
このように、 コンクリ一トマトリックス中に存在する各繊維が加熱後は効果 的な空孔を速やかに形成するため、 繊維使用量を少なくすることができる。 繊 維使用量が少ないため、 コンクリートの流動性に及ぼす影響も小さくなリ、 施 ェ性のよい高強度コンクリートを経済的に実現できることになる。  As described above, since each fiber present in the concrete matrix quickly forms effective pores after heating, the amount of fiber used can be reduced. Since the amount of fiber used is small, the effect on the fluidity of concrete is small, and high-strength concrete with good workability can be economically realized.
これらの有機繊維を構成する有機材料としては、 火災時の加熱によリ分解又 は溶融して体積の急激な減少を起こす、 天然有機材料、 半合成有機材料、 ある いは合成の有機材料が用いられる。  As organic materials constituting these organic fibers, natural organic materials, semi-synthetic organic materials, or synthetic organic materials that are decomposed or melted by heating in a fire to cause a sharp decrease in volume are used. Used.
次に、 5 0 0 °Cに加熱した時の重量残存率の測定方法について説明する。 まず、 有機繊維の気乾質量を測定して 6〜7 m gを秤量し、 示差走査熱分析 法により測定を行う。 具体的な測定条件としては、 示差走査熱量天秤 （商品名 T A S 2 0 0、 理学電気社製） を用いて、 アルミナ製サンプルホルダ一にて、 温度上昇率： 5 . 0 °C/分、 測定時間間隔： 0 . 6秒にて測定する。 Next, a method of measuring the weight residual ratio when heated to 500 ° C. will be described. First, measure the dry weight of the organic fiber, weigh 6 to 7 mg , and measure by differential scanning calorimetry. As specific measurement conditions, using a differential scanning calorimeter (trade name: TAS 200, manufactured by Rigaku Denki Co., Ltd.), using an alumina sample holder, temperature rise rate: 5.0 ° C / min, measurement Time interval: Measure at 0.6 seconds.
有機材料との関係でいえば、 比較的溶融温度の低い繊維であるポリプロピレ ン、 ポリ塩化ビニル、 ポリビニルアルコール、 アクリル繊維等を前記条件で測 定すると、 ポリプロピレン、 ポリビニルアルコールはそれぞれ重量残存率が 1 4 %、 1 8 %であり、 本発明の要件に適合する。 しかし、 ポリ塩化ビニル、 ァ クリル繊維は重量残存率が 3 0 %を超えるため、 本発明の繊維としては適さな い。  Speaking of the relationship with organic materials, when fibers such as polypropylene, polyvinyl chloride, polyvinyl alcohol, and acrylic fibers, which are relatively low in melting temperature, are measured under the above conditions, the residual weight ratio of polypropylene and polyvinyl alcohol is 1 4% and 18%, which meet the requirements of the present invention. However, polyvinyl chloride and acrylic fibers are not suitable as the fibers of the present invention because the residual weight ratio exceeds 30%.
本発明の有機繊維を構成する天然有機材料、 半合成有機材料あるいは合成の 有機材料としては、 加熱によリ溶融又は蒸発して急激な体積の減少が起こリ、 特に 500°Cに加熱した時の重量残存率が 30%以下であることを要する。 そ のため、 公知の合成樹脂類、 天然繊維、 合成繊維及び半合成繊維などから前記 の条件を考慮して選択する必要がある。 好ましい材料の例としては、 ポリプロ ピレン系、 ポリビニルアルコール系、 ビニリデン系などの材料が挙げられる。 次に、 有機繊維の形状について検討するために、 本発明者らはコンクリート モデルを用いて評価を行った。 有機繊維の形状は有機繊維の蒸発によリ形成さ れる空孔の形状に直接関連する。 その空孔、 即ち、 加熱時の耐爆裂性をもたら す水蒸気逃し穴の作用の効果は、 ここで検討する繊維の径、 さらには、 繊維の 混入量、 コンクリートの強度等によって違いを生じる。 The natural organic material, the semi-synthetic organic material, or the synthetic organic material constituting the organic fiber of the present invention may be melted or evaporated by heating to cause a rapid decrease in volume, In particular, the residual weight ratio when heated to 500 ° C must be 30% or less. Therefore, it is necessary to select from known synthetic resins, natural fibers, synthetic fibers, semi-synthetic fibers and the like in consideration of the above conditions. Preferred examples of the material include a polypropylene-based material, a polyvinyl alcohol-based material, and a vinylidene-based material. Next, in order to examine the shape of the organic fiber, the present inventors evaluated using a concrete model. The shape of the organic fiber is directly related to the shape of the pore formed by evaporation of the organic fiber. The effect of the pores, that is, the effect of the water vapor vent hole, which provides resistance to explosion during heating, differs depending on the fiber diameter, the amount of fiber mixed in, and the concrete strength, etc. studied here.
コンクリート中に分散した繊維 （直径 df) の状態を、 図 1 Aに示すように かぶりコンクリート部で均一に被覆され、 平行に分布している状態、 とモデル 化する。 1本の繊維によって火災時に形成される穴には、 図 1 Bに示すような 六角形で近似される筒状のコンクリート部分 （以下 "有効コンクリート柱" と 呼ぶ） からの水蒸気が逃げてくることになる。 この水蒸気の移動を図 1 Cに矢 印で示す。 このように、 繊維によって形成された空孔は、 かぶりコンクリート 部の領域からの水蒸気を穴から外に逃がすことになる。 The state of the fibers (diameter d f ) dispersed in the concrete is modeled as a state in which the fibers are uniformly covered with the cover concrete and distributed in parallel as shown in Fig. 1A. In the hole formed by a single fiber in the event of a fire, water vapor from a cylindrical concrete part (hereinafter referred to as an “effective concrete column”) approximated by a hexagon as shown in Fig. 1B escapes. become. This movement of water vapor is indicated by an arrow in FIG. 1C. In this way, the pores formed by the fibers allow water vapor from the area of the cover concrete to escape from the holes.
六角形の有効コンクリート柱の直径を d。 （mm) 、 繊維の直径を df (m m) 、 繊維の混入量を Vf (cm3 /m3 ) とすると、 dc、 dい Vrの間には 、 下記式 （1 ) の関係があることが算定される。 Hexagon effective concrete column diameter d. (Mm), the diameter of the fiber is d f (mm), and the amount of mixed fiber is V f (cm 3 / m 3 ), the relationship between d c and d or V r is given by the following equation (1): It is calculated that there is.
d„ 式 ( 1 )
Figure imgf000008_0001
d „formula (1)
Figure imgf000008_0001
式 （ 1 ) の dcと Vf の関係を Vf を混入率 （％) に変換し、 繊維の直径をパ ラメ一ターにして、 プロットすると図 2のようになる。 The relationship between d c and V f in Eq. (1) is converted to a mixing ratio (%) of V f, and the diameter of the fiber is set as a parameter.
図 2は有効コンクリート柱の直径 dc (mm) と繊維のコンクリート中への 混入量 Vf (体積％) との関係を、 繊維の直径ごとに示したグラフである。 図 2より、 繊維の混入率が多くなる程、 有効コンクリート柱の直径が小さくなる こと、 及び、 繊維の直径が小さくなる程、 有効コンクリート柱の直径が小さく なることがわかる。 図 1 A〜図 1 Cにモデル図を用いて説明したように、 有効 コンクリ一ト柱の直径が小さい程、 繊維の穴 1つで水蒸気を集めてくる領域が 狭く、 従って、 爆裂防止効果が大きいことになる。 すなわち、 繊維の混入率が 多い程、 繊維の直径が小さい程、 爆裂防止に効果的なことがわかる。 Figure 2 is a graph showing the relationship between the effective concrete column diameter d c (mm) and the amount of fiber mixed into the concrete V f (volume%) for each fiber diameter. Figure From Fig. 2, it can be seen that the diameter of the effective concrete column decreases as the fiber mixing ratio increases, and that the diameter of the effective concrete column decreases as the fiber diameter decreases. As explained using the model diagrams in Figs. 1A to 1C, the smaller the diameter of the effective concrete pillar, the narrower the area where water vapor is collected in one fiber hole, and thus the more effective the explosion prevention effect. It will be big. In other words, it is clear that the higher the fiber mixing ratio and the smaller the fiber diameter, the more effective it is in preventing explosion.
1つの繊維穴に水蒸気を集める速度は、 コンクリートの強度、 すなわち、 組 織の緻密さによって異なる。 そのため、 爆裂防止に必要な有効コンクリート柱 の直径は、 強度が大きくなる程小さくなる。 The rate at which water vapor is collected in one fiber hole depends on the strength of the concrete, that is, the density of the tissue. Therefore, the diameter of the effective concrete column required to prevent explosion decreases as the strength increases.
本発明者らは鉄筋コンクリート柱の載荷加熱実験を行った。 3時間、 強度の 1/3の力を保持 （通常の長期荷重の最大値） するのに必要な繊維の量を、 繊 維径が 20 mのポリプロピレン繊維を用いて、 圧縮強度の異なるコンクリー トに混入して評価した。 コンクリートの圧縮強度 800 k g f /cm2の場合 には、 必要な繊維混入量は 0. 0 1〜 0. 02容量％、 コンクリ一トの圧縮強 度 1 000 k g f Zcm2の場合には、 0. 05容量％程度であった。 これを 図 2のグラフに当てはめて検討するに、 爆裂防止に必要な有効コンクリート柱 の直径は、 コンクリートの圧縮強度が S O O k g fZcm2の場合で 2. 0〜 2. 5 mm程度、 コンクリートの圧縮強度が l O O O k g f Zcm2の場合で 1. Omm前後と推定される。 The present inventors conducted a loading heating experiment on a reinforced concrete column. For 3 hours, the amount of fiber required to maintain 1/3 of the strength (normal maximum value of long-term load) is determined by using polypropylene fibers with a fiber diameter of 20 m and concrete with different compressive strength. And evaluated. When the compressive strength of concrete is 800 kgf / cm 2 , the necessary fiber content is 0.01 to 0.02% by volume, and when the compressive strength of concrete is 1 000 kgf Zcm 2 , it is 0. It was about 05% by volume. To consider fitting it in the graph of FIG. 2, the diameter of the effective concrete column required explosion prevention, 2. 0 2. about 5 mm in case the compressive strength of the concrete is SOO kg fZcm 2, compression of the concrete When the strength is l OOO kgf Zcm 2 , it is estimated to be around 1. Omm.
本発明においては、 高強度コンクリートの耐爆裂性向上の観点から、 少なく ともコンクリートの圧縮強度が 800 k g f Zcm2程度以上であることを考 慮して、 図 1 A〜図 1 Cにモデル図で示した有効コンクリート柱の直径 （dc ) が 2. Omm以下の領域にあるよう設定することが必要であることがわかる 爆裂防止に適した繊維の直径を有効コンクリート柱の直径を考慮して選択す れば、 繊維の直径は 5〜200 mであることが好ましい。 5 ^ πι未満である と水蒸気の経路として好ましい空孔を形成し難く、 2 0 0 t mを超えると高密 度コンクリートに対して十分な耐爆裂性を発現し難い。 In the present invention, from the viewpoint of improving resistance to spalling of high strength concrete, to consider that the compressive strength of at least the concrete is 800 kgf ZCM 2 about above, the model diagram in FIG. 1 A to FIG 1 C It is necessary to set the diameter (d c ) of the effective concrete column shown to be within the range of 2. Omm or less. Select the fiber diameter suitable for preventing explosion considering the diameter of the effective concrete column. Preferably, the fiber diameter is between 5 and 200 m. Less than 5 ^ πι When it exceeds 200 tm, it is difficult to exhibit sufficient explosion resistance to high-density concrete.
また、 繊維の長さは、 5〜4 O mmであることが好ましい。 5 mm未満であ ると爆裂防止効果が不十分であり、 繊維長が 4 O mmを上回るようになると、 繊維の分散が悪くなリ、 均一なコンクリートを得難い。  Further, the length of the fiber is preferably 5 to 4 O mm. If it is less than 5 mm, the effect of preventing explosion will be insufficient, and if the fiber length exceeds 4 Omm, the dispersion of fibers will be poor and it will be difficult to obtain uniform concrete.
これらの有機繊維は、 コンクリート中で凝集することなく、 それぞれが均一 に分散が可能であれば、 モノフィラメントでもストランド状の繊維でも使用す ることができる。  As long as these organic fibers can be uniformly dispersed without agglomeration in concrete, either monofilaments or strand fibers can be used.
これらの有機繊維は、 凝集することなく、 それぞれ実質的に均一に分散する ようコンクリート中に混入される。 これらの有機繊維は、 一度に全量添加され るのではなく、 連続的に少しずつ、 または適用量を分割し、 混合装置を用いる コンクリ一ト材料の練り混ぜ段階の間に少しずつ、 コンクリ一ト材料中に添加 されることが好ましい。  These organic fibers are mixed into concrete so that they are substantially uniformly dispersed without agglomeration. These organic fibers are not added all at once, but rather in small portions continuously or in small portions during the kneading phase of the concrete material using a mixing device. It is preferably added to the material.
高強度コンクリ一卜の爆裂防止に必要な繊維の混入量はコンクリートの体積 に対して 0 . 0 2〜0 . 3容量0 /0、 すなわち、 1 1113当たリ 0 . 2〜 3リットルで ある。 本発明の有機繊維の如く、 高温で速やかに蒸発がおこり、 有効な空隙を 形成しやすい繊維を用いた場合でも、 0 . 0 2容量％すなゎち0 . 2リットル Zm 3未満では爆裂防止効果が不十分であり、 0 . 3容量％すなわち 3リットル Zm3 以上混入すると、 コンクリ トの流動性が低下するため、 いずれも好ましくな い。 0 mixed amount of fiber needed for explosion prevention of high-strength concrete Ichiboku is the volume of the concrete. 0 2 to 0.3 volume 0/0, i.e., 1 111 3 per Li 0. 2 with 3 liters is there. As the organic fiber of the present invention, occur quickly evaporates at high temperatures, even in the case of using the fiber easily forms an effective air gap, 0. 0 2 volume% Sunawachi 0. Explosion prevention is less than 2? Zm 3 If the effect is insufficient and 0.3% by volume, that is, 3 liters Zm 3 or more is mixed, the fluidity of the concrete is reduced, and neither is preferable.
このように本発明の耐爆裂性コンクリートにおいては、 混入した繊維の熱収 縮、 蒸発により連続した空隙が形成され、 そこを次々に水蒸気が伝わることに よリ効率的に水蒸気を外に逃がして爆裂を防止することができる。  Thus, in the explosion-resistant concrete of the present invention, continuous voids are formed by heat shrinkage and evaporation of the mixed fibers, and the steam is transmitted one after another to efficiently escape the steam. Explosion can be prevented.
本発明に係る有機繊維は柔軟性であり、 コンクリート中に分散されても、 そ の流動性に与える影響は少ない。 この繊維を充填材としてコンクリートに分散 することにより、 火災時に発生するコンクリート中の水蒸気を外部へ逃がすこ とで、 コンクリートの爆裂を効果的に防止する。 コンクリートの水結合材比が 35 %を上回る通常のコンクリートの場合には火災時にコンクリートに生ずる 爆裂の影響が問題にならないレベルである。 この発明は、 水結合材比が 35% 以下の高強度コンクリートに適用して特に有用であるといえる。 実施例 The organic fiber according to the present invention is flexible, and has little effect on its fluidity even when dispersed in concrete. By dispersing this fiber into concrete as a filler, water vapor generated in the event of a fire in the event of a fire escapes to the outside, effectively preventing explosion of the concrete. Concrete water binder ratio In the case of ordinary concrete exceeding 35%, the effect of explosion occurring in concrete at the time of fire is a level that does not cause a problem. The present invention can be said to be particularly useful when applied to high-strength concrete having a water binder ratio of 35% or less. Example
以下に、 実施例を挙げて本発明を具体的に説明するが、 本発明はこの実施例に 制限されるものではない。 Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.
実施例 1〜 2  Examples 1-2
1. コンクリートの材料  1. Concrete material
セメント ：普通ポルトランドセメント  Cement: ordinary Portland cement
細骨材 ：山砂 （比重 2. 55、 吸水率 1. 54%) と硬質砂岩  Fine aggregate: mountain sand (specific gravity 2.55, water absorption 1.54%) and hard sandstone
砕砂 （比重 2. 65、 吸水率 1. 26%) を 6 ： 4に混合 粗骨材 ：硬質砂岩砕石 （比重 2. 6、 吸水率 1. 1 2%)  Crushed sand (specific gravity 2.65, water absorption 1.26%) mixed in 6: 4 Coarse aggregate: Hard sandstone crushed stone (specific gravity 2.6, water absorption 1.12%)
混和材 ：粉体シリカフユ一ム （比重 2. 2、 比表面積 14m2Zg、 Admixture: powdered silica film (specific gravity 2.2, specific surface area 14m 2 Zg,
S i 02含有量 94%) S i 0 2 content 94%)
混和剤 ：ポリカルボン酸塩系高性能 A E減水剤 （商品名：チューポール H P 一 1 1、 竹本油脂社製）  Admixture: Polycarboxylate-based high-performance A E water reducer (trade name: Tupole HP-11, Takemoto Yushi Co., Ltd.)
2. コンクリートの調合  2. Mixing concrete
下記表 1に示す水結合材比が 25 %の高強度コンクリートを基材として実験 した。  The experiment was performed using high-strength concrete with a water binder ratio of 25% as shown in Table 1 below.
表 1  table 1
Figure imgf000011_0001
Figure imgf000011_0001
3. 有機繊維 ポリプロピレン繊維で、 直径 20 πι、 長さ 1 9mm、 500 °Cに加熱した 時の重量残存率が 14%のものを用いた。 3. Organic fiber A polypropylene fiber having a diameter of 20πι, a length of 19mm, and a weight retention rate of 14% when heated to 500 ° C was used.
4. 繊維の混入量  4. Fiber content
前記有機繊維を前記で調製したコンクリート中に 0. 05容量％、 0. 1 0 容量％、 0. 20容量％、 0. 30容量％の条件で混入した。  The organic fibers were mixed in the concrete prepared above under the conditions of 0.05% by volume, 0.10% by volume, 0.20% by volume, and 0.30% by volume.
5. コンクリートの製造  5. Manufacture of concrete
1 00リツトルパン型強制練リミキサーを使用した。 1回の練り量を 60リツトルと した。 砂、 セメント、 シリカフユ一ムを 1 5秒空練りした後、 水と混和剤を投 入し 1分練混ぜた後、 粗骨材を投入した。 粗骨材投入後の練混ぜ時間を 2分と し、 最初の 30秒の間で繊維を混入した。 得られたコンクリートのうち、 有機 繊維の混入量が 0. 05容量％のものを実施例 1、 0. 1容量％のものを実施 例 2、 0. 2容量％のものを実施例 3、 0. 3容量％のものを実施例 4とした  A 100 litter pan type forced remixer was used. The amount of each kneading was 60 liters. After sand, cement, and silica foam were kneaded for 15 seconds, water and an admixture were added, kneaded and mixed for 1 minute, and then coarse aggregate was added. The mixing time after the addition of the coarse aggregate was 2 minutes, and the fibers were mixed during the first 30 seconds. In the obtained concrete, the concrete containing 0.05% by volume of organic fiber was used in Example 1, the concrete containing 0.1% by volume was used in Example 2, and the concrete containing 0.2% by volume was used in Examples 3 and 0. . 3% by volume was used as Example 4.
6. コンクリートの流動性試験 6. Concrete flowability test
コンクリートのスランプフローを、 特許登録第 2 58 97 57号に記載の方 法により測定し、 繊維の混入が流動性に及ぼす影響を検討した。 スランプフロ —の高いものが流動性が良い。 結果を下記表 2に示した。 また、 有機繊維を全 く混入しなかったものをコントロール （比較例 1 ) として、 同様の測定を行つ た結果も表 2に併記した。 この流動性と繊維の混入率との関係を図 3のグラフ に示した。  The slump flow of concrete was measured by the method described in Patent Registration No. 2 589 757, and the effect of fiber mixing on fluidity was examined. Higher slump flow has better fluidity. The results are shown in Table 2 below. Table 2 also shows the results of the same measurement, with the control containing no organic fiber as a control (Comparative Example 1). The relationship between the fluidity and the fiber mixing ratio is shown in the graph of FIG.
7. 耐火試験  7. Fire test
水蒸気が蒸発しないよう、 封かん状態で養生した ø 1 5 X 30 cm試験体の 封かんを解いて図 5に示した標準加熱曲線に従って加熱し、 加熱前後の試験体 の重量を測定した。 この試験では、 爆裂したものは重量が軽くなリ、 加熱前後 の重量の差が大きくなる。 従って、 重量変化 （重量減少率） の数値が小さいも のを耐爆裂性に優れていると評価した。 結果を下記表 2に示した。 この重量減 少率と繊維の混入率との関係を図 4のグラフに示した。 比較例 2〜 6 The ø15 × 30 cm test specimen, which was cured in a sealed state, was unsealed and heated according to the standard heating curve shown in Fig. 5, so that the water vapor did not evaporate, and the weight of the test specimen before and after heating was measured. In this test, the explosion has a lighter weight, and the difference in weight before and after heating increases. Therefore, those with a small value of weight change (weight loss rate) were evaluated as having excellent explosion resistance. The results are shown in Table 2 below. The relationship between the weight reduction rate and the fiber mixing rate is shown in the graph of FIG. Comparative Examples 2 to 6
前記実施例 1において、 混入する繊維を前記有機繊維に換えて、 直径 1 7 m、 長さ 20mm、 500 °Cに加熱した時の重量残存率が 7 6%のアクリル繊 維を使用し、 混入量を 0%、 0. 05容量％、 0. 1容量％、 0. 2容量％、 0. 3容量％とした他は、 実施例 1と同様にしてコンクリートを製造し、 それ ぞれ比較例 2〜 6とした。 比較例 2〜 6のコンクリートについても、 実施例 1 と同様に、 前記 （6) コンクリートの流動性試験及び （7) 耐火試験を行った 。 結果を表 2に示した。 表 2  In Example 1, the fiber to be mixed was replaced with the organic fiber, and an acrylic fiber having a diameter of 17 m, a length of 20 mm, and a residual weight of 76% when heated to 500 ° C was used. Concrete was produced in the same manner as in Example 1 except that the amounts were 0%, 0.05% by volume, 0.1% by volume, 0.2% by volume, and 0.3% by volume. 2 to 6. Similarly to Example 1, the concretes of Comparative Examples 2 to 6 were subjected to the (6) concrete fluidity test and (7) fire resistance test. The results are shown in Table 2. Table 2
Figure imgf000013_0001
上記表 2及び図 3のグラフより、 実施例 1〜4では、 繊維を混入しないコン クリート （図 3で繊維混入量 =0の値） に比較して流動性の低下は少なく、 実 用上問題のないレベルであることがわかる。
Figure imgf000013_0001
From the graphs in Table 2 and Fig. 3 above, in Examples 1 to 4, the decrease in fluidity was small compared to the concrete without fiber mixing (fiber mixing amount = 0 in Fig. 3), which was a practical problem. It can be seen that there is no level.
また、 表 2及び図 4のグラフに明らかなように、 耐火試験においては、 実施 例 1〜4の重量変化が、 繊維を混入しないコンクリート （図 4で繊維混入量 = 0の値） に比較して著しく低下しており、 有機繊維 0. 05容量％の混入量で 、 十分に爆裂を防止する効果があることがわかる。 Also, as is clear from the graphs in Table 2 and Fig. 4, in the fire resistance test, the weight change of Examples 1 to 4 was compared with that of concrete without fiber (the value of fiber content = 0 in Fig. 4). Significantly decreased, and the content of organic fiber was 0.05% by volume. However, it can be seen that there is a sufficient effect of preventing explosion.
一方、 本発明の範囲外の有機繊維を混入した比較例 3〜 6では、 耐火試験に おける重量変化は無混入と変わらず、 爆裂防止効果が認められなかった。 産業上の利用可能性  On the other hand, in Comparative Examples 3 to 6 in which organic fibers outside the scope of the present invention were mixed, the change in weight in the fire resistance test was the same as that in the case of no mixing, and no explosion preventing effect was observed. Industrial applicability
本発明は上述のように、 流動性を低下させることなく、 爆裂を効果的に抑制 することができ、 経済性の高い高強度の耐爆裂性コンクリートを提供しうると いう効果を奏する。  As described above, the present invention has an effect that explosion can be effectively suppressed without lowering fluidity, and an economical high-strength explosion-resistant concrete can be provided.

Claims

請求の範囲 The scope of the claims
1. 500°Cに加熱した時の重量残存率が加熱前の 30%以下で、 直径 5〜 200 μπι、 長さ 5〜40 mmである有機繊維を 0. 02〜0. 3容量％含有 し、 水：結合材比が 35%以下であることを特徴とする、 耐爆裂性コンクリ一 卜。 1. Contains 0.02 to 0.3% by volume of organic fiber with a diameter of 5 to 200 μπι and a length of 5 to 40 mm with a weight retention rate of 30% or less before heating at 500 ° C. An explosion-resistant concrete characterized by having a water: binder ratio of 35% or less.
2. 前記有機繊維を構成する有機材料が、 ポリプロピレン、 ポリビニルアル コ一ルからなる群より選択される 1種以上であることを特徴とする、 請求項 1 に記載の耐爆裂性コンクリート。  2. The explosion-resistant concrete according to claim 1, wherein the organic material constituting the organic fiber is at least one selected from the group consisting of polypropylene and polyvinyl alcohol.
3. 前記有機繊維がモノフィラメントであることを特徴とする、 請求項 2に 記載の耐爆裂性コンクリート。  3. The explosion-resistant concrete according to claim 2, wherein the organic fibers are monofilaments.
4. 前記有機繊維がモノフィラメントであることを特徴とする、 請求項 1に 記載の耐爆裂性コンクリート。  4. The explosion-resistant concrete according to claim 1, wherein the organic fibers are monofilaments.
5. 前記有機繊維がポリプロピレンからなることを特徴とする、 請求項 4に 記載の耐爆裂性コンクリート。  5. The explosion-resistant concrete according to claim 4, wherein the organic fibers are made of polypropylene.
6. 前記有機繊維がコンクリ一ト中で実質的に均一に分散していることを特 徴とする、 請求項 1に記載の耐爆裂性コンクリート。  6. The explosion-resistant concrete according to claim 1, characterized in that the organic fibers are substantially uniformly dispersed in the concrete.
7. 500°Cに加熱した時の重量残存率が加熱前の 30%以下で、 直径 5〜 7.The residual weight ratio when heated to 500 ° C is 30% or less before heating, and the diameter is 5 ~
200 μπι、 長さ 5〜4 Ommであり、 コンクリート中で実質的に均一に分散 しているストランド状繊維を 0. 02〜0. 3容量％含有し、 水：結合材比が200 μπι, 5 to 4 Omm in length, containing 0.02 to 0.3% by volume of strand-like fibers that are substantially uniformly dispersed in concrete.
35%以下であることを特徴とする、 耐爆裂性コンクリート。 Explosion-resistant concrete characterized by being 35% or less.
8. 前記ストランド状繊維が有機材料からなることを特徴とする、 請求項 7 に記載の耐爆裂性コンクリ一ト。  8. The explosion-resistant concrete according to claim 7, wherein the strand fibers are made of an organic material.
9. 前記ストランド状繊維を構成する有機材料が、 ポリプロピレン、 ポリビ ニルアルコールからなる群よリ選択される 1種以上であることを特徴とする、 請求項 8に記載の耐爆裂性コンクリート。 9. The explosion-resistant concrete according to claim 8, wherein the organic material constituting the strand fibers is at least one selected from the group consisting of polypropylene and polyvinyl alcohol.
1 0. 前記ストランド状繊維を構成する有機材料が、 ポリプロピレン、 ポリ ビニルアルコールからなる群よリ選択される 1種以上であることを特徴とする 、 請求項 7に記載の耐爆裂性コンクリート。 10. The explosion-resistant concrete according to claim 7, wherein the organic material constituting the strand fibers is at least one selected from the group consisting of polypropylene and polyvinyl alcohol.
1 1. 前記ストランド状繊維を成す材料が実質的にモノフィラメント材料で あることを特徴とする、 請求項 7に記載の耐爆裂性コンクリ一ト。  1 1. The explosion-resistant concrete according to claim 7, wherein the material forming the strand-like fibers is substantially a monofilament material.
1 2. 前記ストランド状繊維が有機材料を含有することを特徴とする、 請求 項 1 1に記載の耐爆裂性コンクリート。  12. The explosion-resistant concrete according to claim 11, wherein the strand fibers contain an organic material.
1 3. 前記ストランド状繊維が、 ポリプロピレン、 ポリビニルアルコールか らなる群より選択される 1種以上を含有することを特徴とする、 請求頊 1 1に 記載の耐爆裂性コンクリート。  13. The explosion-resistant concrete according to claim 11, wherein the strand-like fibers contain at least one selected from the group consisting of polypropylene and polyvinyl alcohol. 13.
14. (a) 500°Cに加熱した時の重量残存率が加熱前の 30 %以下で、 直径 5〜200 ; mである繊維を加える工程；および  14. (a) adding a fiber having a weight retention rate of 30% or less before heating at 500 ° C and a diameter of 5 to 200; m; and
(b)セメントに前記繊維、 骨材、 水および結合材を、 前記繊維が実質的に 均一に分散するよう所要量を連続的にまたは分割して段階的に加え、 かつ水： 結合材比が 3 5%以下となるように混合する工程、 を含むことを特徴とする 、 耐爆裂性コンクリート作成方法。  (b) adding the fiber, aggregate, water and binder to cement continuously or stepwise in required amounts so that the fibers are substantially uniformly dispersed, and the water: binder ratio is A method for producing explosion-resistant concrete, characterized by including a step of mixing so as to be 35% or less.
1 5. 前記繊維を加える工程において、 加える前記繊維の長さが実質的に 4 0mm以下であることを特徴とする、 請求項 14に記載の耐爆裂性コンクリ一 ト作成方法。  15. The method according to claim 14, wherein, in the step of adding the fibers, the length of the fibers to be added is substantially 40 mm or less.
1 6. 前記繊維を加える工程において、 加える前記繊維の長さが実質的に 5 mm以上であることを特徴とする、 請求項 1 4に記載の耐爆裂性コンクリート 作成方法。  16. The method for producing explosion-resistant concrete according to claim 14, wherein, in the step of adding the fiber, the length of the fiber to be added is substantially 5 mm or more.
1 7. 前記繊維を加える工程において、 加える前記繊維が有機材料からなる ことを特徴とする、 請求頊 14に記載の耐爆裂性コンクリート作成方法。  17. The method for producing explosion-resistant concrete according to claim 14, wherein in the step of adding the fiber, the fiber to be added is made of an organic material.
1 8. 前記繊維を加える工程において、 加える前記繊維がポリプロピレン、 ポリビニルアルコールからなる群より選択される材料からなることを特徴とす る、 請求項 1 4に記載の耐爆裂性コンクリ一ト作成方法。 18. The method of claim 14, wherein in the step of adding the fiber, the fiber to be added is made of a material selected from the group consisting of polypropylene and polyvinyl alcohol. .
1 9. 前記繊維を加える工程において、 加える前記繊維の長さが実質的に 5 mm以上 40mm以下であることを特徴とする、 請求項 1 8に記載の耐爆裂性 コンクリート作成方法。 19. The method for producing explosion-resistant concrete according to claim 18, wherein, in the step of adding the fiber, the length of the fiber to be added is substantially 5 mm or more and 40 mm or less.
20. 前記繊維を加える工程において、 加える前記繊維が有機材料からなる ことを特徴とする、 請求項 1 9に記載の耐爆裂性コンクリート作成方法。  20. The method for producing explosion-resistant concrete according to claim 19, wherein in the step of adding the fiber, the fiber to be added is made of an organic material.
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FR0005956A FR2808795A1 (en) 2000-05-10 2000-05-10 Concrete resistant to rupture useful for buildings and tunnels contains an organic fiber having a specified residual weight percentage after heat treatment at a specified temperature and has specified diameter and specified length
NO20025314A NO20025314D0 (en) 2000-05-10 2002-11-06 Concrete that does not peel during fire
DK200201717A DK200201717A (en) 2000-05-10 2002-11-08 Concrete with improved resistance to peeling
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