JP2006206401A - Abutment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abutment for use in manufacturing a prestressed concrete member with a pretensioning method, which can easily adjust the length between load-bearing walls, and which can be stored in a small space. <P>SOLUTION: The abutment 1 comprises either (1) reaction members 3 composed of a hardened body of a formulation containing at least cement, a very fine pozzolan powder, fine aggregate, water and a water reducing agent, and steel load-bearing walls 2, or (2) reaction members 3 composed of a hardened body of a formulation containing at least cement, a very fine pozzolan powder, fine aggregate, water and a water reducing agent, and load-bearing walls 2 composed of a hardened body of a formulation containing at least cement, a very fine pozzolan powder, fine aggregate, water and a water reducing agent. The reaction members are manufactured by joining columnar members or wall-like members which are 0.5-2 meters long. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an abut used when a prestressed concrete member is manufactured by a pretension method.

  The production of prestressed concrete members by the pretension method is a method in which the PC steel material is pulled, the concrete is driven between them, the PC steel material is loosened after a predetermined compressive strength is obtained, and the prestress is introduced by adhesion between the concrete and the steel material. . In the production of a prestressed concrete member by this pretension method, conventionally, an abutment as shown in FIG. 3 is used as an apparatus used for pulling a PC rope. The abutment 5 shown in FIG. 3 is composed of a load bearing wall 6 and a cylindrical reaction force member 7, and a PC steel material (not shown) is pulled and fixed between the load bearing walls 6 facing an appropriate distance. . And the reaction force member 7 supports the reaction force at the time of pulling and fixing PC steel materials.

In general, since abuts pull and fix a large number of PC ropes, a large compressive force acts on the reaction force member as a reaction force of the tensile force of the PC steel (Non-patent Document 1).
Therefore, conventionally, the reaction force member has been manufactured from iron or steel.
Tetsuo Hashimoto, “Practical Prestressed Concrete Handbook”, Sankai-do Co., Ltd., September 10, 1963, p. 9

  However, in an abut having an iron or steel reaction member, it is difficult to adjust the length between the bearing walls, and it is difficult to manufacture prestressed concrete members having different dimensions (lengths). . There is also a problem that a large space is required for storing the abut.

  The present invention has been made in view of the above-mentioned problems and knowledge of the prior art, and its purpose is to make it possible to easily adjust the length between the bearing walls and reduce the storage space. Is to provide.

  As a result of diligent research, the present inventor has produced a reaction force member with an ultra-high strength cementitious hardened body having ultra-high strength characteristics and the like, and the reaction force member is a columnar member or a wall shape having a length of 0.5 to 2 m It has been found that the above problems can be solved by joining the members, and the present invention has been completed.

That is, the present invention is an abut comprising at least a reaction force member comprising a hardened body of a composition containing cement, pozzolanic fine powder, fine aggregate, water and a water reducing agent, and a steel bearing wall, The reaction force member is an abutment formed by joining columnar members or wall-shaped members having a length of 0.5 to 2 m (Claim 1). The present invention also includes a reaction member comprising a cured product of a composition containing at least cement, pozzolanic fine powder, fine aggregate, water and a water reducing agent, and at least cement, pozzolanic fine powder, fine aggregate, An abut comprising a load bearing wall made of a cured product of a composition containing water and a water reducing agent, wherein the reaction member is a columnar member or a wall member having a length of 0.5 to 2 m. The abut is (claim 2).
In the present invention, the compound contains an inorganic powder having an average particle diameter of 3 to 20 μm (Claim 3), or one or more fibers selected from the group consisting of metal fibers, organic fibers, and carbon fibers (Claims). 4) is preferably included.

  In the abutment of the present invention, it is easy to adjust the length between the bearing walls, and it becomes easy to produce prestressed concrete members having different dimensions (lengths). Further, when the abutment is not used, the reaction force member can be disassembled and stored, so that the storage space can be reduced.

Hereinafter, the present invention will be described in detail.
The abut of the present invention comprises (1) a reaction force member made of a cured product of a composition containing at least cement, fine pozzolanic powder, fine aggregate, water and a water reducing agent, and a steel bearing wall, or ,
(2) At least a reaction member made of a cured product of a composition containing cement, pozzolanic fine powder, fine aggregate, water and a water reducing agent, and at least cement, pozzolanic fine powder, fine aggregate, water and water reduced Consisting of a load bearing wall made of a cured product of a composition containing an agent,
The reaction member is formed by joining columnar members or wall members having a length of 0.5 to 2 m.

First, the material and composition of the cured body constituting the reaction force member and the bearing wall will be described.
Examples of the cement for the hardened body include various Portland cements such as ordinary Portland cement, early-strength Portland cement, medium heat Portland cement, and low heat Portland cement.
In the present invention, when trying to improve the early strength of the cured body, it is preferable to use early-strength Portland cement, and when trying to improve the fluidity of the blend, It is preferred to use low heat Portland cement.

Blaine specific surface area of the cement, preferably ^{2500~5000cm 2 / g, 3000~4500cm 2 /} g is more preferable. If the value is less than 2500 cm ² / g, the hydration reaction becomes inactive and the strength of the cured product decreases, and if it exceeds 5000 cm ² / g, it takes time to grind the cement. Moreover, since the amount of water for obtaining a predetermined fluidity increases, there is a drawback that the strength of the cured body is lowered.

Examples of the pozzolanic fine powder include silica fume, silica dust, fly ash, slag, volcanic ash, silica sol, and precipitated silica.
In general, silica fume and silica dust have a BET specific surface area of 5 to 25 m ² / g and do not need to be pulverized, and thus are suitable as the pozzolanic fine powder of the present invention.
BET specific surface area of the pozzolanic substance fine powder is preferably ^{5~25m 2 / g, 5~18m 2 /} g is more preferable. When the value is less than 5 m ² / g, there are disadvantages such as a decrease in strength of the cured body, and when it exceeds 25 m ² / g, the amount of water for obtaining a predetermined fluidity increases, There are drawbacks such as reduced strength.
The blending amount of the pozzolanic fine powder is 5 to 50 parts by mass, preferably 10 to 40 parts by mass with respect to 100 parts by mass of cement. When the blending amount is out of the range of 5 to 50 parts by mass, the fluidity of the blend is lowered, so that there are disadvantages that it takes time to manufacture the reaction force member and the bearing wall.

As the fine aggregate, river sand, land sand, sea sand, crushed sand, silica sand and the like, or a mixture thereof can be used. In the present invention, it is preferable to use a fine aggregate having a maximum particle size of 2 mm or less, and more preferably a fine aggregate having a maximum particle size of 1.5 mm or less in view of the strength of the cured body. From the viewpoint of fluidity of the blend, it is preferable to use a fine aggregate having a particle content of 75 μm or less of 2.0% by mass or less, and a fine aggregate having a particle content of 75 μm or less of 1.5% by mass or less. It is more preferable to use
The blending amount of the fine aggregate is preferably 50 to 250 parts by weight, preferably 80 to 200 parts by weight with respect to 100 parts by weight of cement, from the viewpoint of the fluidity of the blend and the strength of the hardened body. Is more preferable.

As the water reducing agent, a lignin-based, naphthalenesulfonic acid-based, melamine-based, or polycarboxylic acid-based water reducing agent, an AE water reducing agent, a high-performance water reducing agent, or a high-performance AE water reducing agent can be used. Among these, it is preferable to use a high performance water reducing agent or a high performance AE water reducing agent having a large water reducing effect, and it is more preferable to use a polycarboxylic acid-based high performance water reducing agent or a high performance AE water reducing agent.
The blending amount of the water reducing agent is preferably 0.1 to 4.0 parts by mass, more preferably 0.1 to 2.0 parts by mass in terms of solid content with respect to 100 parts by mass of cement. If the blending amount is less than 0.1 parts by mass, kneading becomes difficult, fluidity is lowered, and there are drawbacks such as time-consuming production of reaction force members and bearing walls. If the blending amount exceeds 4.0 parts by mass, material separation and significant setting delay may occur, and the strength of the cured product may be reduced.
The water reducing agent can be used in a liquid or powder form.

  The amount of water is preferably 10 to 30 parts by mass, more preferably 12 to 25 parts by mass with respect to 100 parts by mass of cement. When the amount of water is less than 10 parts by mass, kneading becomes difficult, fluidity is lowered, and there are drawbacks such as time and effort for producing the reaction force member and the bearing wall. When the amount of water exceeds 30 parts by mass, there is a drawback that the strength of the cured product is lowered.

In the present invention, an inorganic powder having an average particle size of 3 to 20 μm, more preferably an average particle size of 4 to 10 μm, from the viewpoint of improving the fluidity of the compound, the strength development property and durability of the cured product. Is preferably included. Increasing the fluidity of the blend facilitates the production of reaction force members and bearing walls.
Examples of the inorganic powder include slag, limestone powder, feldspar, mullite, alumina powder, quartz powder, fly ash, volcanic ash, silica sol, carbide powder, and nitride powder. Among these, slag, limestone powder, and quartz powder are preferably used in terms of cost and quality stability after curing.
The blending amount of the inorganic powder is preferably 50 parts by mass or less, more preferably 10 to 40 parts by mass with respect to 100 parts by mass of cement, from the viewpoint of fluidity of the blend, strength of the cured body, and the like.

In this invention, it is preferable to mix | blend 1 or more types of fibers chosen from the group which consists of a metal fiber, an organic fiber, and a carbon fiber from a viewpoint which raises the intensity | strength, yield strength, etc. of a hardening body significantly.
Metal fibers are blended from the viewpoint of greatly increasing the bending strength of the cured body, and in particular, when producing a bearing wall with a cured body of the blend, it is possible to blend metal fibers into the blend. preferable.
Examples of metal fibers include steel fibers, stainless fibers, and amorphous fibers. Among these, steel fibers are excellent in strength and are preferable from the viewpoint of cost and availability. The size of the metal fiber is preferably 0.01 to 1.0 mm in diameter and 2 to 30 mm in length from the viewpoint of preventing material separation of the metal fiber in the composition and improving the bending strength of the cured body. Is more preferably 0.05 to 0.5 mm and the length is 5 to 25 mm. The aspect ratio (fiber length / fiber diameter) of the metal fiber is preferably 20 to 200, more preferably 40 to 150.

The shape of the metal fiber is preferably a shape that imparts some physical adhesion (for example, a spiral shape or a waveform) rather than a straight shape. If it is in a spiral shape or the like, the stress is secured while the metal fibers and the matrix are pulled out, so that the bending strength is improved.
Preferable examples of metal fibers include, for example, interfacial adhesion to a matrix of a cementitious hardened body made of steel fibers having a diameter of 0.5 mm or less and a tensile strength of 1 to 3.5 GPa and having a compressive strength of 120 N / mm ^2. The strength (maximum tensile force per unit area of the adhesion surface) is 3 N / mm ² or more. In this example, the metal fiber can be processed into a corrugated or helical shape. Moreover, the groove | channel or processus | protrusion for resisting the motion (longitudinal slip) with respect to a matrix can also be attached on the surrounding surface of the metal fiber of this example. The metal fiber of this example has a metal layer having a Young's modulus smaller than the Young's modulus of the steel fiber on the surface of the steel fiber (for example, one or more selected from zinc, tin, copper, aluminum, etc.) It is good also as what provided.

  The blending amount of the metal fiber is preferably 4% or less, more preferably 0.5 to 3%, and particularly preferably 1 to 3% in terms of volume percentage in the blend. When the blending amount exceeds 4%, the unit water amount increases to ensure fluidity and the like, and even if the blending amount is increased, the reinforcing effect of the metal fiber is not improved. Since it becomes easy to produce what is called a fiber ball in it, it is not preferable.

The organic fiber and the carbon fiber are blended from the viewpoint of increasing the breaking energy of the cured body.
Examples of the organic fiber include vinylon fiber, polypropylene fiber, polyethylene fiber, and aramid fiber. Among these, vinylon fibers and / or polypropylene fibers are preferably used in terms of cost and availability.
Examples of the carbon fiber include PAN-based carbon fiber and pitch-based carbon fiber.
The dimensions of the organic fibers and carbon fibers are preferably 0.005 to 1.0 mm in diameter and 2 to 30 mm in length from the viewpoint of preventing material separation of these fibers in the formulation and improving the fracture energy after curing. More preferably, the diameter is 0.01 to 0.5 mm and the length is 5 to 25 mm. Further, the aspect ratio (fiber length / fiber diameter) of the organic fiber and the carbon fiber is preferably 20 to 200, more preferably 30 to 150.

  The blending amount of the organic fiber and the carbon fiber is preferably 10.0% or less, more preferably 1.0 to 9.0%, particularly preferably 2.0 to 8.0% by volume percentage in the blend. If the blending amount exceeds 10.0%, the unit water amount increases to ensure fluidity and the like, and even if the blending amount is increased, the fiber reinforcing effect is not improved. Since it becomes easy to produce what is called a fiber ball, it is not preferable.

The kneading method of the blend is not particularly limited. For example, (1) materials other than water and a water reducing agent are mixed in advance to prepare a premix material, and the premix material, water and water reduction (2) Prepare a powdery water reducing agent, mix materials other than water in advance to prepare a premix material, and mix the premix material and water with the mixer. (3) A method in which each material is individually fed into a mixer and kneaded, etc. can be employed.
The mixer used for kneading may be of any type used for ordinary concrete kneading. For example, a rocking mixer, a pan type mixer, a biaxial kneading mixer, or the like is used.

The molding and curing of the compound can be performed by a normal concrete molding method and curing method, and casting molding, vibration molding, and the like can be applied, and normal temperature curing, normal pressure steam curing, and the like can be applied.
In the method described in “JIS R 5201 (Cement physical test method) 11. Flow test”, the above-mentioned blend preferably has a value of 230 mm or more measured without performing 15 dropping motions. If the value is less than 230 mm, the fluidity is lowered, and it takes time to manufacture the reaction force member and the bearing wall, which is not preferable.
Further, the cured product of the formulation, 120 N / mm ² or more, preferably 130N / mm ² or more, more preferably it is preferred to express the 140 N / mm ² or more compression strength. If the compressive strength is less than 120 N / mm ² , it is difficult to support the reaction force when the PC tie is pulled and fixed, which is not preferable.
In addition, it is preferable that the cured body of the blend exhibits a bending strength of 20 N / mm ² or more, preferably 23 N / mm ² or more.

Next, the shape of the abutment according to the present invention will be described with reference to FIGS.
FIG. 1 is a side view showing an example of an abut according to the present invention, and FIG. 2 is a cross-sectional view taken along the line AA of FIG. The abutment 1 shown in FIG. 1 is composed of a steel bearing wall 2 and a reaction force member 3 made of a hardened body of a composition containing cement, pozzolanic fine powder, fine aggregate, water, and a water reducing agent. . Each reaction force member 3 is formed by joining five columnar columnar members 3a made of a hardened material of a composition containing cement, pozzolanic fine powder, fine aggregate, water and a water reducing agent.
FIG. 1 shows an example in which five columnar columnar members are joined. In the present invention, the length between the bearing walls 2 can be adjusted as appropriate by changing the number of joined columnar members. It is.
FIG. 1 is an example in which a cylindrical columnar member is joined as a reaction force member. However, in the present invention, a prismatic columnar member can be used instead of the columnar columnar member. Wall-like members can also be used.
Further, FIG. 1 is an example composed of a steel bearing wall. In the present invention, the bearing wall is also composed of a hardened body of a composition containing cement, fine pozzolanic powder, fine aggregate, water and a water reducing agent. can do.

In the present invention, the length of the columnar member or wall-shaped member is preferably 0.5 to 2 m. If the length of the columnar member or the wall-shaped member is less than 0.5 m, the number of columnar members or wall-shaped members constituting the reaction force member increases, and it takes time to assemble the reaction force member. When the length of the columnar member or the wall-shaped member exceeds 2 m, the mass of the columnar member or the wall-shaped member is increased, and it takes time to assemble the reaction force member.
The cross-sectional area of the columnar member or the wall-shaped member (for example, the area of a circle in the case of a columnar columnar member) can be appropriately determined according to the reaction force when the PC steel material is pulled and fixed.

  In the present invention, the method of joining the columnar member or the wall-shaped member is not particularly limited and can be joined with an adhesive or the like. However, considering the labor of assembly and disassembly of the reaction force member, the columnar member or It is preferable to form a through-hole in the wall-shaped member and to join the through-hole through a steel material or the like.

Hereinafter, the present invention will be described by way of examples.
[1. Materials used]
The following materials were used.
(1) Cement; Low heat Portland cement (manufactured by Taiheiyo Cement)
; Blaine specific surface area 3200cm ² / g)
(2) Pozzolanic fine powder; silica fume (BET specific surface area 10 m ² / g)
(3) Inorganic particles: quartz powder (average particle size 7.0 μm)
(4) Fine aggregate: quartz sand (maximum particle size 0.6mm, content of particles less than 75μm 0.3% by mass)
(5) Metal fiber: Steel fiber (diameter: 0.2mm, length: 13mm)
(6) Water reducing agent; polycarboxylic acid-based high-performance water reducing agent (7) Water; tap water

Example 1
100 parts by mass of low heat Portland cement, 32 parts by mass of silica fume, 120 parts by mass of silica sand, 1.0 part by mass of high-performance water reducing agent (solid content with respect to cement), and 22 parts by mass of water were charged into a biaxial mixer and kneaded.
The flow value of the blend was measured in the method described in “JIS R 5201 (Cement physical test method) 11. Flow test” without performing 15 drop motions. As a result, the flow value was 280 mm.
Further, the blend was poured into a mold of φ50 × 100 mm, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The cured body had a compressive strength (average of three) of 210 N / mm ² .
The blend was poured into a 4 × 4 × 16 cm mold, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The bending strength (average value of three pieces) of the cured body was 25 N / mm ² .

Example 2
100 parts by weight of low heat Portland cement, 32 parts by weight of silica fume, 39 parts by weight of quartz powder, 120 parts by weight of silica sand, 1.0 part by weight of high-performance water reducing agent (solid content with respect to cement) and 22 parts by weight of water are put into a biaxial mixer and kneaded. did.
The flow value of the blend was measured in the method described in “JIS R 5201 (Cement physical test method) 11. Flow test” without performing 15 drop motions. As a result, the flow value was 285 mm.
Further, the blend was poured into a mold of φ50 × 100 mm, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The cured body had a compressive strength (average value of 3) of 225 N / mm ² .
The blend was poured into a 4 × 4 × 16 cm mold, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The bending strength (average value of 3 pieces) of the cured body was 27 N / mm ² .

Example 3
Low heat Portland cement 100 parts by weight, silica fume 32 parts by weight, quartz powder 39 parts by weight, silica sand 120 parts by weight, high performance water reducing agent 1.0 part by weight (solid content with respect to cement), water 22 parts by weight, steel fiber (volume in the formulation) 2%) was put into a biaxial mixer and kneaded.
The flow value of the blend was measured in the method described in “JIS R 5201 (Cement physical test method) 11. Flow test” without performing 15 drop motions. As a result, the flow value was 265 mm.
Further, the blend was poured into a mold of φ50 × 100 mm, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The cured body had a compressive strength (average of three) of 230 N / mm ² .
The blend was poured into a 4 × 4 × 16 cm mold, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The bending strength (average value of 3 pieces) of the cured product was 47 N / mm ² .

It is a side view of one example of the abutment of the present invention. It is AA sectional drawing of the abutment of FIG. It is a side view of one example of the conventional abutment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Abut 2 Bearing wall 3 Reaction force member 3a Cylindrical columnar member 4 PC steel material fixing | fixed part 5 Abut 6 Load bearing wall 7 Reaction force member

Claims (4)

  There is an abutment composed of a hardened body of a composition containing at least cement, fine powder of pozzolanic material, fine aggregate, water and a water reducing agent, and a steel bearing wall, and the length of the reaction member is long. An abutment formed by joining columnar members or wall-shaped members of 0.5 to 2 m.   At least a reaction force member composed of a cured product of a composition containing cement, pozzolanic fine powder, fine aggregate, water and water reducing agent, and at least cement, pozzolanic fine powder, fine aggregate, water and water reducing agent An abut comprising a load-bearing wall made of a cured product of the composition, wherein the reaction member is formed by joining columnar members or wall-like members having a length of 0.5 to 2 m.   The abutment according to claim 1 or 2, wherein the blend contains an inorganic powder having an average particle size of 3 to 20 µm.   The abutment according to any one of claims 1 to 3, wherein the blend contains one or more fibers selected from the group consisting of metal fibers, organic fibers, and carbon fibers.

Images