JP2933959B2 - Anchoring structure of fiber reinforced synthetic resin concrete reinforcing rod - Google Patents

Description

The present invention relates to a prestressed concrete tendon,
The present invention relates to an anchoring structure of a concrete reinforcing rod made of fiber reinforced synthetic resin (hereinafter, referred to as FRP) used as a substitute for reinforcing steel for concrete reinforcement.

"Prior art and problems to be solved by the invention" Cases in which FRP rods are used in recent years to overcome the problems of corrosion and magnetism of steel bars used for prestressed concrete tensile steel, concrete reinforcing bars, etc. However, since the surface of the FRP rod has low friction, various fixing methods have been developed to secure the fixing property of the fixing end portion.

As a fixing method of the conventional FRP concrete reinforcing rod, FR inserted through a sleeve with a tapered inner surface
A wedge fixing method in which a plurality of wedges are fitted into a tapered gap around a P-tension material to fix the material
269962) and by inserting a wedge-shaped FRP tendon with a cut in the fixing end into a sleeve with rough irregularities on the inner surface, and filling it with low-shrink grout. An integrated wedge grout fixing system (Japanese Utility Model Laid-Open No. 1-96926) is known, but in the former, the frictional force between the smooth peripheral surface and the inner surface of the wedge is opposed to the tensile force of the FRP tendon. Therefore, there is a problem that sufficient fixing strength cannot be obtained, and when the frictional force is increased by providing irregularities around the tendon material, there is a problem in uniform fixing along the line circumferential surface, and the fixing efficiency is reduced. It has the drawback of being very low, and in the latter case, the tension member is not joined by the internal pressure depending on the low shrinkage grout in the sleeve, so that the pulling force is transmitted to this, and there is a problem that it breaks at the forked intersection of the cut. Was.

Also, in the sleeve, cut a plurality of cuts at the fixing end, insert a pin in each cut, insert a FRP tendon expanded in a wedge shape, and fill with an epoxy adhesive. Therefore, in the wedge adhesive fixing method of uniting and integrating (Japanese Patent Laid-Open No. 60-203761), there was a problem in the stability of the epoxy adhesive, and it was difficult to obtain sufficient adhesive strength.

In addition, a special wedge fixing method that fixes the FRP tendon material inserted in the sleeve with double inner and outer wedges (Japanese Patent Laid-Open No. 60-26
No. 8370) is also known, but it requires a special tensioning device for pushing the external wedge into the sleeve in the tensioned state of the tensioning material, and is applied to a tensioning material having irregularities in order to directly fix the tensioning material to the wedge. It was very difficult.

Further, a reinforcing fiber is wound around the fixing end of the fiber-reinforced synthetic resin tendon material in a tapered shape to form a wedge, and the wedge-shaped end is fixed by a fiber-wound wedge fixing system (Japanese Patent Laid-Open No.
No. -203763) is also known, but at the factory, complicated processing of winding the fiber around the fiber-reinforced synthetic resin material is required, and at the same time, the strength of the wound fiber layer itself and the adhesive strength of the layer to the tendon are increased. There was anxiety, and there was a drawback that the establishment of a large tension was not reliable.

As an indirect fixation, a wedge fixing method with a cushioning material is also known in which a cushioning material is coated on a fiber-reinforced synthetic resin tendon and fixed with a wedge, but depending on the selection of the cushioning material and the presence of oily water. There was a disadvantage that the fixing efficiency was impaired.

In addition, a fixing sleeve with an increased friction particle layer formed on the inner surface and a FRP tendon material with an increased friction particle layer formed on the surface inserted inside the fixing sleeve are cured with a curable filler filled between them. There is also known a fixing sleeve coupling structure formed by uniting the fixing sleeves.

However, since a general filler such as a synthetic resin is used as the curable filler used in this bonding structure, it has been difficult to obtain a sufficient fixing strength.

[Means for Solving the Problems] In order to solve the above-mentioned conventional problems, the present invention has a fixing sleeve whose inner surface is subjected to a friction increasing surface treatment and whose opening end is reduced in diameter, and which is inserted into the inside thereof. The peripheral surface of the end portion of the FRP toning agent whose surface has been subjected to a friction increasing treatment is hardened in a pressurized state by the expansion hardening of a hydraulic and high-strength grout material having a quick-setting and expanding property filled between them. are sintered, in the high strength grout compressive strength upon curing 600 Kg / cm ² or more,
An object of the present invention is to provide a fixing structure of a fiber-reinforced synthetic resin concrete reinforcing rod made of a hydraulic cement-based glow material adjusted so as to generate an internal pressure of 400 kg / cm ² or more in the fixing sleep.

`` Action '' The hydraulic high-strength grout material filled in the fixing sleeve with quick-setting and expandability expands and hardens in the radial direction of the sleeve because the opening end of the sleeve is reduced in diameter. With the inner surface of the sleeve and the peripheral surface of the FRP rod uniformly compressed with high internal pressure, they are united and united with high strength in a short time.

Reinforcing fiber is wrapped around the fixing end of the FRP rod,
Since the friction-enhancement treatment with improved surface adhesion properties, such as using stranded wires, is performed, it is completely integrated with the high-strength united grout in the compressed state, and the tensile force acting on the FRP rod is transmitted through the united grout. It is transmitted to the sleeve.

On the other hand, since the inner surface of the sleeve has been subjected to friction-enhancing surface treatment such as blasting and grinding, it is integrated with the high-strength united grout in a compressed state, and maintains a uniform bonding force that sufficiently opposes the tensile force As a result, a fixing section having high fixing performance and excellent fixing efficiency can be obtained.

"Example" Hereinafter, the present invention will be described with reference to an example shown in the drawings. The FRP rod 1 used in the fixing structure of the present invention is a synthetic resin rod containing fibers such as carbon, aramid, glass, etc. At the fixing end,
Reinforcement yarn or tape of synthetic resin or the like is spirally wound, hoop-shaped, etc. to form irregularities on the peripheral surface, countless small protrusions on the peripheral surface, or use FRP stranded wire, etc. A friction increasing treatment has been performed to improve the adhesion characteristics.

A fixing sleeve 2 for fixing the fixing end of the FRP rod 1 has an opening at one end or both ends as shown in FIGS.
The ends of the 3 and 3 'are formed in a cylindrical shape whose diameter is reduced to the extent that the FRP rod 1 can be inserted, and the inner peripheral surface thereof is subjected to a blasting treatment, a grinding treatment, etc. for improving the surface adhesion characteristics. A friction-enhancing surface treatment is applied.

The fixing end of the FRP rod 1 is inserted into the fixing sleeve 2, and a gap between the periphery of the FRP rod 1 and the inner surface of the sleeve 2 is filled with a hydraulic high-strength grout material 4 having a quick-setting and expandable property. By hardening, the inner surface of sleeve 2 and FRP
The rod 1 is united with high strength in a state where the peripheral surface is uniformly compressed with a high internal pressure.

Therefore, the FRP rod 1 subjected to the friction-increasing treatment is completely integrated with the high-strength united grout 4 in the compressed state in which the internal pressure is applied in the radial direction in the sleeve 2, and the sleeve subjected to the friction-increasing surface treatment 2 is integrated with the high-strength united grout 4 in a compressed state, and as a result, a uniform bonding force capable of sufficiently resisting the tensile force of the FRP rod 1 is maintained.

1 and 2 show an example in which one FRP rod 1 is fixed. In the example of FIG. 1, an opening 3 having a reduced diameter at one end is shown.
The opening 3 ′ at the other end has the same diameter as the inner diameter of the sleeve and is closed by a cap 6 screwed into a tensioning device connecting screw 5 formed on the outer periphery of the sleeve 2.

In addition, in the example of FIG.
3 'is provided.

FIGS. 3 and 4 show an example in which a plurality of FRP rods 1 are simultaneously fixed to one large-diameter sleeve 2.
A plurality of openings 3 are formed on one end surface of the sleeve 2.

The grout material 4 is preferably injected through the rear end opening 3 'of the sleeve 2 or an injection hole provided at an appropriate position around the sleeve.
It is also possible to insert the rod 1.

The tension can be introduced by screwing a tension rod to the tensioning device connecting screw 5 of the sleeve 2 or by connecting the tension rod with a wedge or a chucking device.
Tension the FRP rod 1 using a jack.

FIG. 5 shows an example in which the FRP rod 1 is fixed as a concrete reinforcing material instead of a reinforcing bar. The sleeve 2 on which the FRP rod 1 is fixed is fixed to the fixing plate 7 and is integrally embedded in the cast concrete. .

The required properties of the grout material 4 for achieving the fixing effect of the present invention include the adhesion strength of the FRP rod 1, the bonding force between the sleeve 2 and the grout material 4, the inner diameter and length of the sleeve 2,
It is determined from various factors such as the coefficient of friction of the inner surface, and can be expressed by the following equation from a mechanical point of view according to the structural principle diagram of the present invention in FIG.

L: FRP rod anchoring length d: FRP rod diameter A _p : FRP rod cross-sectional area l _t : FRP rod outer peripheral length σ _pu : FRP rod tensile strength σ _B : FRP rod adhesion strength D: Sleeve diameter l: Inner circumferential length of sleeve μ: Friction coefficient of sleeve (inner circumferential surface) σ _ep : Grout internal pressure σ _e : Grout restraining force = μ ・ σ _{eP In the} above formula, the diameter d of the FRP rod is now 1.0 cm, and its tension is The strength σ _pu is 160 kg / mm ² , the sleeve diameter is 3.0 cm,
For the case of 2.0 cm, the required fixing length L (cm) is shown in Table 1 when the internal pressure of the sleeve and the internal friction coefficient are changed, respectively.

In the above equation, the bonding strength of the FRP rod σ _B
To about 150Kg / cm ² (experimental value) and its tensile strength to 160Kg
/ mm ² and the diameter d are assumed to be 1.0 cm, the fixing length L is 26 cm from the equation on the right side of the above equation.

When the fixing length L is 26 cm, the grout internal pressure is 200 kg / cm ² or more when the sleeve inner diameter D is 3 cm and the friction coefficient μ = 0.25 from Table 1, and the sleeve inner diameter D is 2 cm and the friction coefficient μ = 0.25. It can be seen that the grout internal pressure at the time of (3) is required to be 300 kg / cm ² or more in design.

When the fixing length L is set to 26 cm in the same manner as described above, the inflation pressure of the grout when the sleeve friction coefficient μ = 0.25 is 200 kg / g.
cm ² or more, and grout inflation pressure when the sleeve friction coefficient mu = 0.5 is found to require the design to 100 Kg / cm ² or more.

The grout strength at this time should be 400 kg / cm ² , 600
It can be set to Kg / cm ² or more.

As described above, in the present invention, the necessary fixing effect can be easily achieved by setting the internal pressure, the expansion pressure, the strength, and the like of the grout material 4 according to the specifications of the fixing specification, and adjusting the blending accordingly. One of the features is that a fixing structure can be obtained.

The grout material 4 used to achieve the present invention is
It must have expandability to apply an internal pressure in the sleeve 2, must have rapid hardening to complete fixing quickly in a short time, and must have high strength to maintain proof strength against high compressive force. If necessary, a cement paste comprising Portland cement, calcium aluminate, gypsum, an expansive cement admixture, a setting retarder, and a high-performance water reducing agent, or a mortar obtained by adding fine sand to this paste is used.

Portland cement in the grout material 4 of the present invention is Portland cement indicated by JISF5210, JISR
Blast furnace cement represented by 5211, silica cement represented by JISR5212, and the like are used, but those which are less strong in strength than those using ordinary Portland cement are not preferred.

Calcium aluminate in the grout material 4 of the present invention refers to CaO (hereinafter abbreviated as C) and Al ₂ O by calcining a calcareous raw material, an alumina raw material, or a halogenated compound by a kiln or melting by an electric furnace. ₃ (hereinafter abbreviated as a) and a compound _{CA, C 3 a, C 17} a 7 or calcium halo aluminate halogen element represented by C ₁₁ a ₇ · CaX ₂ was dissolved (X is Fe, C _{And the} like, and the use of these amorphous materials is preferred.

The mixing ratio of this calcium aluminate is 10 to 10% of clinker powder containing calcium haloaluminate as a main component.
The proportion is 30 to 90 parts by weight of Portland cement with respect to 70 parts by weight, and preferably 50 to 70 parts by weight of Portland cement with respect to 30 to 50 parts by weight of clinker powder. Then, in the case of using a clinker powder based on C ₁₂₁ A ₇ is the ratio of the Portland cement 70 to 97 parts by weight based on the powder 3 to 30 parts by weight (preferably, clinker powder 5-20 80 to 95 parts by weight of Portland cement to parts by weight).

In addition, JIS2511 alumina cement for refractories can also be used.

As the gypsum in the grout material 4 of the present invention, dihydrate / anhydrous / hemihydrate gypsum can be used. However, when a large amount of hemihydrate gypsum is used, the cement composition of the present invention is kneaded with water. Condensation may occur and hinder the fixing operation.

Further, gypsum released during the production of the expandable cement admixture described below can also be used.

The amount of gypsum used for the cement-based grout material 4 of the present invention is 5 to 20 parts by weight based on 100 parts by weight of the mixture of Portland cement and calcium aluminate.

The expandable cement admixture in the grout material 4 of the present invention refers to a quick-lime crystal obtained by appropriately mixing raw materials such as limestone, silica stone, and viscosity, and firing by a kiln or melting by an electric furnace. A clinker made of arit crystals, 30-80
Composition and that an appropriate amount mixed parts by weight gypsum, limestone, properly blended raw material such as alumina raw material and gypsum, a mineral obtained by melting by baking or or an electric furnace by kiln C ₃ A _3. A composition containing CaO ₄ as a main component.

These expandable cement admixtures have a compressive strength of 600K when the high-strength grout material 4 of the present invention is hardened, in consideration of the fixing specifications, in consideration of the thickness of the grout material 4.
It is adjusted so that the internal pressure is at least 400 kg / cm ² within the sleeve 2 at g / cm ² or more.

The setting retarder in the grout material 4 according to the present invention refers to a material which comprises at least one of calcium carbonate, citric acid, gluconic acid and the like, and sets the setting time of the cement material to JISR5201.
Finished by setting test of "Physical Testing Method of Cement" by 10
Add the amount to make it about 30 minutes.

The high performance water reducing agent in the grout material 4 of the present invention is JI
SA6204 “Chemical admixture for concrete” and JISSST402
Powdered and liquid materials conforming to the "Standards for fluidizing agents for concrete" are used, and the amount of addition should be such that the ratio of water to cement-based grout material is 25 to 40 parts by weight. its falling value by J ₁₄ funnel method described in "construction procedure of filling mortar expansive (draft)" Appendix 2 "design and construction guidelines for expanded concrete (draft)" is the amount of 3 to 10 seconds preferable.

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

<Example 1> As a grout material, it was weighed at the compounding ratio shown in Table-2,
The kneading was performed for 90 seconds by a mixer used in JISR5201.

Prerequisite items 1) Fluidity test: J ₁₄ funnel method 2) Breathing test: JISA1123 3) Setting test: JISR5201 4) Compressive strength test: JISA5201 In addition, gluconic acid is used as a setting retarder, and Table 2 is used in advance.
The test was performed according to the setting shown in Table 1 in accordance with the setting time of 10 to 30 minutes.

As a high-performance water reducing agent, "Mighty 100" manufactured by Kao Corporation was used, and the addition amount was 1 part by weight based on the cement grout.

From the results in Table-2, all are excellent in quick-hardening property, expandability,
It can be seen that high compressive strength can be obtained. Particularly, according to Formulations Nos. 2 and 5, excellent fast-curing properties and expansion occur early, so that the fixing work of the FRP rod can be achieved in about 3 to 12 hours. It becomes possible.

<Example 2> Using the same grout material as in Example 1, it was fixed on a sleeve test piece (steel pipe having a length of 200 mm, a diameter of 20 mm, and a thickness of 3.2 mm) shown in FIG. A tensile test (tensile load: 160 kg / mm ² ) of 20 mm in diameter was performed.

 Table 3 shows the results.

From the results in Table 3, it can be seen that 200 to 300 kg / mm ² constraint strength can be obtained in a short period of time.

“Effects of the Invention” As described above, according to the present invention, the following effects can be obtained.

1) It has a fast-setting and expandable hydraulic property filled in the fixing sleeve, and has a compressive strength of 60 when cured.
A high-strength grout material adjusted so that the internal pressure is 400 kg / mm ² or more in the sleeve at 0 kg / mm ² or more,
The open end expands and hardens in the radial direction of the reduced-diameter sleeve, and can be united and integrated in a short time with high strength while the inner surface of the sleeve and the peripheral surface of the FRP rod are uniformly compressed with high internal pressure. .

2) The FRP rod fixing end has been subjected to friction-enhancing treatment to improve the surface adhesion characteristics, and the inner surface of the sleeve has been subjected to friction-enhancing surface treatment such as blasting and grinding. Fully integrated with the united grout that maintains high compressive strength, maintains a uniform bonding force that sufficiently opposes the tensile force acting on the FRP rod, and provides a fixing structure with high fixing performance and excellent fixing efficiency. Can be achieved.

3) The internal pressure, strength, etc. of the grout material can be easily adjusted according to the fixing specifications by the composition of the expandable grout and the filling thickness of the grout material, and since the grout material has a high strength, the high internal pressure is high. And high compressive strength is obtained.

4) Since the grout material has quick-setting properties, a large amount of
It becomes possible to fix the FRP rod.

5) Since it is combined under high internal pressure and high compressive strength,
The fixing of a plurality of FRP rods can be easily performed by using the individual sleeves.

[Brief description of the drawings]

1 to 3 are longitudinal side views each showing a specific example of the fixing structure of the present invention, FIG. 4 is a cross-sectional front view of FIG. 3, and FIG. 5 is used as a reinforcing material alternative to a reinforcing bar by the fixing structure of the present invention. FIG. 6 is a structural principle view of the present invention, and FIG. 7 is a perspective view showing a test body used in Embodiment 2 of the present invention. 1 FRP rod, 2 Fixing sleeve, 3, 3 'Opening, 4 Grout material.

 ────────────────────────────────────────────────── ─── Continued on the front page (73) Patent holder 999999999 Denki Kagaku Kogyo Co., Ltd. 1-4-1, Yurakucho, Chiyoda-ku, Tokyo (72) Inventor Toshiyuki Tachibana 4-40-6 Higashi-Omiya, Omiya-shi, Saitama (72) Inventor Tomoyoshi Chujo 588 Sekido 588, Tama City, Tokyo (72) Inventor Hironobu Nishiyama 4-1-32 Mita, Minato-ku, Tokyo 606 Claire Mita 606 (72) Inventor Kentaro Fujii 4-1096-32 (Minawacho, Narashino City, Chiba Prefecture) 72) Inventor Koji Nakagawa 366 Tomari, Asahi-cho, Shimoshinagawa-gun, Toyama Prefecture (56) References JP-A-63-272850 (JP, A) JP-A-1-154946 (JP, A)

Claims (1)

(57) [Claims] 1. A fixing sleeve having an inner surface subjected to a friction increasing surface treatment and having an opening end reduced in diameter, and a peripheral surface of an end portion of an FRP tendon material subjected to a friction increasing treatment to a surface inserted therein. However, the high-strength hydraulic grout material having a quick-setting and expanding property filled between them is consolidated in a pressurized state by expansion and hardening, and the high-strength grout material has a compressive strength at the time of curing.
In 600 kg / cm ² or more, the internal pressure 4 in the fixing in sleep
An anchoring structure for a fiber reinforced synthetic resin concrete reinforcing rod, comprising a hydraulic cement grout material adjusted so as to generate 00 kg / cm ² or more.