JPH1182869A - Corrosion protective method of tension anchor body for steel product for prestressed concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corrosion protective method of a tension anchor body for a steel product for prestressed concrete used for a common cable (C.C. box culvert), a bridge beam, and the like. SOLUTION: In this corrosion protective method of a tension anchor body for a steel product for prestressed concrete, a protective cap 6 made of plastic and slightly larger than a tension anchor body 5 is fitted to the tension anchor body 5 for clipping a steel product for prestressed concrete protruded from the end of a specified precast concrete construction, and then resin adhesive material 9 is filled from a filling hole 7 provided at the tip of the protective cap 6. Filling is stopped upon confirming that the resin adhesive filled in a clearance part 10 formed between the tension anchor body 5 and the protective cap 6 overflows out of an air vent hole 8 provided at the base end part of the protective cap 6. Corrosion protection of the whole area of the tension anchor body 5 including a steel end part is performed by outside air cutoff of this resin adhesive material 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PC steel material used for a PC steel material (PC steel wire, PC steel rod, PC steel stranded wire, etc.) used for a precast concrete structure such as a C.C.BOX pipeline or a bridge. The present invention relates to a method for preventing a tension-fixed body from being corroded.

[0002]

2. Description of the Related Art Generally, a steel end protruding from an end face of a PC steel material penetrating a precast concrete structure, such as a C / C / BOX conduit (wire common groove) or a girder of a bridge, is provided with: A tension fixing body (fixing device) is mounted to perform clip fixing. In this case, since the tension fixing body projects from the end face of the structure, corrosion occurs in the tension fixing body formed of a metal member and the end portion of the steel material. Therefore, some anticorrosive means must be applied to the tension fixing body. No. As a conventional method for preventing corrosion, a rust-preventive cap was used.

[0003]

However, in the embodiment in which the rust prevention cap (protection cap) having a simple hollow structure is merely fitted to the tension fixing body at the end of the structure as described above, air is inevitably present inside. Therefore, rust is caused on the tension fixing body and the end portion of the PC steel material in long-term use. It is also known that as a means of preventing corrosion, a tension fixing body is simply covered with mortar or concrete, but this is used for a very long time and rust is generated inside due to cracks and the like. .

Further, an anticorrosion method in which a tension-fixed body at the end of a building is provided on a concrete lid plate having a lid-like shape to be joined to an end face of the building, and is exposed to a receiving hole for fixing, and concrete is injected into the receiving hole for fixing from outside. Although there is a means, it cannot be confirmed from the outside whether or not concrete has been filled over the entire tension fixing body having irregularities.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has been made to solve the above-described problem by simply providing a protective cap for filling a resin-based adhesive material on a tightening fixing body projecting from an end face of a predetermined structure. It is an object of the present invention to provide a method for preventing corrosion of a tension fixing body for PC steel which solves the above.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a plastic fixing cap, which is slightly larger than the tension fixing body, is fitted to a tension fixing body that clips a PC steel projecting from a predetermined precast concrete construction end. The resin-based adhesive is injected from the injection hole at the tip of the protective cap, and the resin-based adhesive filled in the gap formed between the tension fixing member and the protective cap is removed from the air vent hole at the base end of the protective cap. After the overflow of the resin-based adhesive is confirmed, the injection is stopped, and the entire area of the tension fixing body including the end portion of the steel material is protected from corrosion by blocking the outside air of the resin-based adhesive.

[0007] A plastic protection cap slightly larger than the tension fixing body is fitted to a tension fixing body that clips a PC steel projecting from a predetermined precast concrete building end, and then an injection hole at the tip of the protection cap is inserted. More resin-based adhesive is injected, and the resin-based adhesive filled in the gap formed between the tension fixing body and the protective cap is injected after confirming overflow from the air vent hole at the base end of the protective cap. Stopping, blocking the outside air of the resin adhesive to prevent corrosion of the entire tension fixing body including the end portion of the steel material, and providing the protective cap on one surface of a concrete end plate joined to the end surface of the building. The seal is made to face the concave groove.

In this case, the resin-based adhesive is made of ABS resin,
It is a resin-based adhesive having adhesive properties such as PP resin.

As described above, the method of preventing the tension fixing body for PC steel from being corroded is such that a plastic protective cap is fitted to the tension fixing body which is formed by clipping the end of the PC steel projecting from the end face of the precast concrete structure, and the resin cap is contained in the protection cap. When the adhesive is injected and it is confirmed that a part of the filled resin-based adhesive overflows from the air vent hole provided at the base end of the protective cap, the resin-based adhesive injected under pressure is protected by the tension fixing body and the protection. Since the air inside the gap between the caps is filled to every corner and the resin-based adhesive overflows from the air vent hole, the internal air is pushed out, the tension fixing including the end portion of the steel material protruding from the end face of the structure. The entire body is reliably shut off from the outside air,
An anticorrosion effect is exhibited.

In another aspect of the present invention, a separate concrete connection end plate is joined to the end face of the building, and after the protective cap fitted to the tension fixing member is filled with a resin-based adhesive, Since the cap receiving groove provided on one side of the concrete connection end plate is faced and covered to form a sealed shape, the tension fixing body and the protective cap are not exposed from the front position of the connection end plate.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The following is a description of an apparatus for directly implementing the method for directly preventing the corrosion of a tension fixing member for PC steel according to the present invention.

FIGS. 1 to 6 show a precast concrete structure using a PC steel wire as a PC steel strand and a C.C.BOX.
The example used was shown. Reference numeral 1 denotes a precast concrete C / C / BOX which serves as an electric wire common groove, and a plurality of the C / C / BOXs 1 are vertically arranged in a longitudinal direction (not shown).
And a PC steel stranded wire 3 is inserted into a longitudinally tightened sheath hole 2 penetrating an appropriate portion thereof, and a distal end portion of the PC steel stranded wire 3 is buried in a CC, BOX 1 at an end position. It is guided to the outside through the through hole 4a of the plate part 4, and a known tightening and fixing body 5 composed of a grip part 5a and a wedge part 5b is mounted on the protruding line part 3a, and a predetermined vertical tightening operation is performed. The strand 3 is fixed to the grip. At this time, the protruding line portion 3a of the PC steel stranded wire 3 protruding from the tightening fixing body 5 after the tensioning is appropriately cut, and the steel material end portion 3b is left slightly. Reference numeral 6 denotes a slightly larger plastic protective cap fitted to the tightening and fixing member 5 including the exposed steel material end portion 3b. The protective cap 6 has a large-diameter cylindrical portion 6a fitted to the tightening and fixing member 5 and a steel material end. It has a two-stage cylindrical structure having a small-diameter cylindrical portion 6b into which the portion 3b is fitted, and has an injection hole 7 at the tip (cap top) and an air vent 8 at the base end, which also serves as an adhesive outflow. Reference numeral 9 denotes a resin-based adhesive that is filled in a filling gap 10 formed between the tightening and fixing body 5 and the protective cap 6. The resin-based adhesive 9 is, for example, ABS.
It is formed by combining an adhesive resin such as resin, PP resin and a predetermined adhesive. 11 is C ・ C ・ BOX
1 is a concrete connection end plate joined to the end surface of No. 1.

Now, the method for preventing corrosion of the tightened fixing body will be described in detail. First, in forming the C.C.
A number of C.BOXs 1 are vertically arranged as appropriate, and a PC steel stranded wire 3 inserted into the vertically tightened sheath hole 2 is inserted into the C.C.BO at the end position.
X1 is guided outward through the anchor plate portion 4, and the fastening and fixing member 5 is fitted and attached to the protruding line portion 3a, and a known fastening operation (wedge fastening in the drawing) is performed to perform CC. B
The OX1 group is vertically tightened to form a pipeline configuration (see FIG. 3). Note that the protruding line portions 3a are cut at appropriate locations.

Here, anticorrosion means is applied to the tightening and fixing body 5 including the steel material end portion 3b projecting from the end face of the CC box 1.

That is, a slightly larger plastic protection in which a predetermined filling gap 10 is formed between the tightening and fixing body 5 and the entirety of the tightening and fixing body 5 including the steel material end portion 3b on the end surface of the CC box 1. A set in which the cap 6 is fitted so that its base end is fitted into the sheath hole step 12 (see FIG. 5). Thereafter, the resin-based adhesive 9 is injected from the injection hole 7 at the tip of the protective cap 6 using an appropriate injector (not shown) having, for example, a cylinder mechanism.

Next, the viscous resin-based adhesive 9 injected under pressure into the protective cap 6 sequentially flows into the gap 10 between the protective cap 6 and the tightening and fixing member 5 and is present in the protective cap 6. When the air flowing out of the protective cap 6 is confirmed as well as pushing the air to be blown toward the base and confirming that the resin-based adhesive 9 overflows from the air vent hole 8 provided at the base end (confirmation from the outside of the protective cap 6), the air flows into the gap 10. This means that the filling is completed without remaining (see FIG. 6). The injection operation may be stopped after confirming the stage at which the resin-based adhesive 9 flows out from the air vent hole 8. The resin-based adhesive 9 hardens in a short time, and the entire area of the tightening and fixing body 5 including the steel end portion 3b, which is a metal member that is easily corroded, is completely immersed in the resin-based adhesive 9 and is shielded from the outside air, thereby preventing corrosion.

Thereafter, in addition to the above-mentioned use, the C
In the embodiment in which the concrete connection end plate 11 having a constant thickness is joined to the end face of the C.BOX 1, the concrete connection end plate is provided on the protective cap 6 which is in a protruding state after completion of filling of the resin-based adhesive. A hollow cap-receiving groove 13 provided on one side (inside) of the end plate 11 is exposed at the time of joining.
When 1 is attached to CC box 1 in a predetermined manner, protective cap 6 is sealed inside (see FIG. 1). The cap receiving groove 13 has an inner tapered shape so that the protective cap 6 can be easily inserted.

FIGS. 7 and 8A and 8B show another embodiment of the protective cap. In this case, the shape of the protective cap 6 is changed so that the resin-based adhesive 9 can be easily filled into a part of the large-diameter cylindrical portion 6a fitted to the tightening and fixing member 5 and the amount of the resin-based adhesive can be reduced. Therefore, the tapered portion 14 is formed by cutting the protruding corner on the small-diameter cylindrical portion 6b side. At this time,
The inflow of the resin-based adhesive material 9 injected from the injection hole 7 at the tip of the protective cap 6 flows smoothly from the tapered portion 14 to the large-diameter cylindrical portion 6a side and is reliably filled to the end.

Another embodiment shown in FIG. 9 is a type in which a PC steel material is used as a PC steel bar, and a tightening and fixing body at this time is configured as a nut. In this case, a nut 5 'serving as a tightening and fixing body is screwed and clipped to the protruding line portion 3a of the PC steel bar 3' protruding from the end of the predetermined construction 1 '. Thereafter, the protective cap 6 was fitted to the nut 5 'including the steel material end portion 3b', and the resin-based adhesive 9 was injected from the injection hole 7 at the tip of the protective cap 6, and the internal gap 10 was filled. After confirming that the resin-based adhesive material 9 overflows from the air vent hole 8 at the base end, if the injection of the resin-based adhesive material 9 is stopped, the entire nut 5 'of the tightening and fixing body including the steel end portion 3b' is made of resin. It is covered with the system adhesive 9 to prevent corrosion.

[0020]

As described above, according to the method for preventing corrosion of the tension anchoring body for PC steel of the present invention, the PC steel (PC steel wire, PC steel rod, PC steel stranded wire, etc.) projecting from the end of a predetermined construction is used. A slightly larger plastic protective cap is fitted to the tension fixing body to be clipped, and a resin-based adhesive is injected into the gap between the protection cap and the tension fixing body, and overflow from the air vent hole at the base end of the protection cap is confirmed. Since the injection was stopped at the stage where it was done, the air in the protective cap was replaced with resin-based adhesive,
The tightening and fixing member including the end portion of the metallic steel material, which is a factor of corrosion, is completely shut off from the outside air, thus providing reliable corrosion protection. That is, since corrosion prevention for this kind of tension fixing body is made of a combination of a protective cap and a resin-based adhesive, it can be easily performed only at the location of the tension fixing body.

Further, in the embodiment in which the concrete end plate is joined to the end of the construction, it is not necessary to form a cutout hole for the filling and fixing body on the side of the concrete end plate, and the fixing plate has a thickness width of the end plate. The mortar or concrete does not need to be poured into the entire body notch hole, and the on-site kneading of the mortar or concrete is omitted. Moreover, when a resin-based adhesive is used, it can be hardened in one to two hours and can be constructed in a short time without requiring a fixed curing period unlike conventional mortar or concrete.

Further, since the plastic protective cap is used, the resin-based adhesive can be injected even when the tightening and fixing member is wet, which also has the effect of speeding up anticorrosion work.

[Brief description of the drawings]

FIG. 1 shows a PC according to the present invention using a CC / BOX conduit as a construct.
It is explanatory drawing which shows the corrosion prevention method of the tension fixing body of the Example which used steel material as PC steel strand.

FIG. 2 shows a plastic protective cap.
(A) is a side view, (B) is a front view.

FIG. 3 is an explanatory view showing a tightening and fixing body facing an end surface of a CC box.

FIG. 4 is an explanatory view in which a tension fixing member is attached to a PC steel strand inserted into a CC box.

FIG. 5 is an explanatory view in which a plastic protective cap is fitted to the tension fixing member.

FIG. 6 is an explanatory view of filling a gap between the tension fixing member and the protective cap with a resin-based adhesive.

FIG. 7 is an explanatory view of an anticorrosion method using a plastic protective cap of another embodiment.

FIG. 8 shows the plastic protective cap.
(A) is a side view, (B) is a front view.

FIG. 9 is an explanatory view in which a plastic protective cap is fitted to a tightening and fixing body of another embodiment and a resin-based adhesive is filled.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 C ・ C ・ BOX 3 PC stranded wire 3a Protruding wire portion 5 Tightening fixing body 6 Plastic protective cap 7 Injection hole 8 Air vent hole 9 Resin adhesive 10 Gap 11 Concrete connection end plate 13 Cap receiving concave groove

Continuing on the front page (72) Keiichi Kobayashi, Inventor 2-1-1, Kabukicho, Shinjuku-ku, Tokyo Residence within Ken Concrete Industry Co., Ltd. (72) Inventor Jiro Kondo 2-2-115, Kabukicho, Shinjuku-ku, Tokyo Ken-Concrete Industry Co., Ltd. (72) Inventor Motoya Sugiyama 2-2-1-15 Kabukicho, Shinjuku-ku, Tokyo, Japan Residence Ken-Concrete Industry Co., Ltd. (72) Inventor Yasuo Endo 1-10-6 Takaban, Meguro-ku, Tokyo No. Inside Hako Co., Ltd.

Claims (3)

[Claims] 1. A tension anchor for clipping a PC steel projecting to a predetermined precast concrete construction end,
After fitting a plastic protective cap slightly larger than the tension fixing body, a resin-based adhesive is injected through an injection hole at the tip of the protection cap to fill a gap formed between the tension fixing body and the protection cap. After confirming that the resin-based adhesive overflowed from the air vent hole at the base end of the protective cap and stopped the injection, the outside air of the resin-based adhesive was blocked to prevent corrosion of the entire tension-fixing body including the steel end. A method for preventing corrosion of a tension-fixed body for PC steel, characterized by performing the following. 2. A tension anchor for clipping a PC steel projecting to a predetermined precast concrete construction end,
After fitting a plastic protective cap slightly larger than the tension fixing body, a resin-based adhesive is injected through an injection hole at the tip of the protection cap to fill a gap formed between the tension fixing body and the protection cap. After confirming that the resin-based adhesive overflowed from the air vent hole at the base end of the protective cap and stopped the injection, the outside air of the resin-based adhesive was blocked to prevent corrosion of the entire tension-fixing body including the steel end. A method for preventing corrosion of a tension fixing body for PC steel, wherein the protective cap is made to face a cap receiving groove formed on one side of a concrete end plate joined to an end face of a building and is sealed. 3. The resin-based adhesive according to claim 1, wherein said resin-based adhesive is an adhesive resin-based adhesive such as ABS resin or PP resin.
The anticorrosion method of the tension fixing body for PC steel described in the above.