JPH084284Y2 - Concrete structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a concrete structure in which the surface layer of a concrete member is reinforced.

[Problems to be Solved by Conventional Techniques and Inventions] Conventionally, reinforcing materials such as reinforcing bars and wire mesh, which is a small-diameter welded wire mesh, have been used for concrete structures.
However, when a reinforcing bar is used, a large covering is required, so that it is difficult to dispose it on the surface layer of the concrete member, the workability is not sufficient, and it is difficult to reduce the weight. When using a wire mesh,
Although it is possible to reduce the weight to some extent, it is still insufficient. Moreover, when reinforcing bars or wire meshes are used, not only rusting and insufficient durability, but also the effect of reinforcing the surface layer is small and the concrete members are likely to crack.

An object of the present invention is to provide a concrete structure that is lightweight, has excellent reinforcement of the concrete surface layer portion, and can prevent cracking.

[Construction of device] When the reinforcing fibers are knitted into a mesh-shaped mesh weave structure and a reinforcing material integrated with a resin is arranged on the surface layer of concrete, the inventors of the present invention provide a planar surface layer reinforcement. We found that the effect is great and cracks can be effectively prevented,
The present invention has been completed. That is, the present invention solves the above-mentioned problems by the concrete structure in which the reinforcing material is knitted into the mesh-shaped mesh weave structure and the resin-integrated reinforcing material is arranged in the surface layer portion of the concrete member. It is a thing.

Examples of the reinforcing fiber constituting the reinforcing material include polymer fibers such as polyacrylonitrile, phenol resin, rayon, etc., carbon fibers made of petroleum or coal pitch, etc .;
Examples include alkali resistant glass fibers; aromatic polyamide fibers; high strength vinylon fibers; polyether sulfone fibers and the like. At least one kind of the reinforcing fiber is used.

Among these reinforcing fibers, carbon fiber is preferable. In addition,
Carbon fiber means carbonized or graphitized fiber, 1500 ℃
Those that are fired at a high temperature above a certain level are included in the concept of graphitization even when the crystal structure is not graphitized. When carbon fibers are used as the reinforcing fibers, electromagnetic wave shielding properties can be imparted.

The reinforcing fiber is preferably a fiber having a tensile elastic modulus of 5 × 10 ³ kgf / mm ² or more.

The reinforcing fiber is usually composed of about 500 to 30,000 filaments. The diameter of the reinforcing fiber is usually 0.1-10 mm,
It is preferably about 0.5 to 5 mm.

The reinforcing fibers are knitted in a mesh-shaped simulated weave structure. As shown in FIG. 1, the dummy weave design has a characteristic that the warp fiber (1) and the weft fiber (2) are alternately crossed in a form that does not easily shift, and the crimp of the fiber is small. The mesh spacing L of the mesh-shaped dummy weave structure can be appropriately set according to the reinforcing performance,
The mesh interval L = 2 mm or more, particularly L = 8 to 30 mm is preferable. If the mesh interval L is less than 2 mm, the amount of cement mortar filled between the meshes is small and the reinforcing property is insufficient. The reinforcing property can be controlled by adjusting the thickness and strength of the reinforcing fiber used, the mesh interval, and the like. Further, in the mesh-like reinforcing material, the cement mortar matrix can be filled between the warp fiber (1) and the weft fiber (2), so that the adhesive force between the concrete and the reinforcing material is significantly improved. The warp fibers (1) and the weft fibers (2) of the weave texture may be regularly knitted or irregularly knitted. Further, the number of warp fibers and weft fibers is not particularly limited, and can be appropriately set depending on the reinforcing property and the like.

The warp fiber (1) and the weft fiber (2) may be composed of different kinds of fibers. In that case, carbon fiber may be used for one of the warp fiber (1) and the weft fiber (2), and an inexpensive fiber may be used for the other. Further, in order to prevent misalignment of the mesh-shaped simulated weave structure, for example, nylon fibers or polyester fibers may be used for sealing.

The knitted fabric of the above-mentioned dummy weave structure is integrated with a thermosetting resin or a thermoplastic resin. Examples of the resin include thermosetting resins such as epoxy resin, phenol resin, vinyl ester resin, diallyl phthalate resin, unsaturated polyester resin, thermosetting acrylic resin, polyurethane resin and polyimide; polyacetal, polysulfone, polyether sulfone, polyphenylene. Examples include thermoplastic resins such as sulfide, polyphenylene oxide, polyarylate, and aromatic polyamide. The above resins are used alone or in combination of two or more. Of these resins, thermosetting resins, particularly epoxy resins and phenol resins, whose characteristics are less likely to be deteriorated by the alkaline component of cement, are preferable. In addition, when using a thermosetting resin, the hardening | curing agent according to the kind of resin is used. The thermosetting resin can be usually cured at a temperature of room temperature to about 20 ° C.

The amount of resin impregnated into the fibers has a volume content of 30 to 80.
% Is preferable. If the impregnation rate is less than 30%, the integrity of the fiber and the reinforcing effect will be reduced, and if it exceeds 80%, it will be difficult to form a composite and the strength at the intersection will be reduced, and the reinforcing effect will be reduced.

The resin can be impregnated by a conventional method, for example, by immersing the knitted product in a resin solution or applying a resin solution. The resin is dried and cured to form an integrated reinforcing material. Is obtained. The above-mentioned curing is not limited to the cross-linking and curing of the thermosetting resin, and is used to include the solidification of the thermoplastic resin. The reinforcing material may be woven into a mesh shape, then the knitted product may be integrated with a resin, or fibers may be impregnated with the resin in advance and then woven into a mesh shape.

The reinforcing material is lightweight because the knitted mesh-shaped knitted fabric is integrated with the resin, and is excellent in adhesion to cement mortar. Further, it is less deformed by stress in any direction, and is excellent in stress transmission and workability. Further, since it has a small crimped weave structure, the strength of the reinforcing fiber itself can be efficiently exhibited.
In particular, it is remarkably excellent in the adhesive strength at the intersection of the fibers. Therefore, the reinforcing property can be improved with a small amount, and excellent reinforcing property is imparted to the concrete member.

In addition, the reinforcing material may be surface-treated with a silane coupling agent, a titanium coupling agent, or the like in order to enhance affinity with concrete, and further, sand may be attached to the surface or polishing may be performed. The uneven portion may be formed by.

FIG. 2 is a sectional view showing an embodiment of the concrete structure of the present invention.

The concrete structure (13) is made up of concrete members (1
2) and a reinforcing material (11) of the above-mentioned simulated weave structure arranged on the surface layer of the concrete member (12). When the thickness of the concrete member (12) is T, the preferable arrangement position of the reinforcing material (11), that is, the cover C is usually within the range of 0 <C ≦ T × 0.15, and particularly 0 <C ≦ T × 0.10. Is.

The concrete structure (13) as described above has the concrete member (12) due to the surface reinforcement effect of the reinforcing material (11).
To prevent cracks on the surface layer. For example, JIS A 5326 specifies that in a prestressed concrete sheet pile, at a crack moment of 0.78 tonf, the crack width is 0.05 mm or less, but the concrete structure (13) above meets the above conditions. I am fully satisfied.

The reinforcing material (11) may be arranged on at least one surface layer of the concrete member (12). In the concrete member (12), at least the reinforcing material (11) needs to be arranged in the surface layer portion, and a reinforcing bar or other reinforcing material may be arranged together with the reinforcing material (11).

The concrete member (12) is, for example, self-hardening cement such as Portland cement, early-strength Portland cement, alumina cement, rapid-hardening high-strength cement, burnt gypsum, etc .; hydraulic cement such as lime slag cement, blast furnace cement; mixed cement, etc. Can be formed of cement. Further, the cement may contain an aggregate, a setting retarder, a hardening accelerator, a water reducing agent, a coagulant, a thickener, a foaming agent, a waterproofing agent and the like.

[Effects of the Invention] As described above, in the concrete structure of the present invention, since the reinforcing fibers having a specific woven structure are arranged on the surface layer portion of the concrete member, it is lightweight, and the reinforcing property of the concrete surface layer portion is improved. It is excellent and can prevent cracks.

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples.

Example 1 Mesophase pitch was melt-spun, infusibilized, and then fired at a temperature of 1200 ° C. in a nitrogen gas atmosphere, followed by surface treatment and sizing agent application treatment, which consisted of 6000 filaments with a wire diameter of 10 μm. A pitch-based carbon fiber was obtained. Carbon fiber has a tensile strength of 200 kgf / mm ² and a tensile modulus of 18 × 10 ³ kgf
It was / mm ² .

Use 3 of each of the obtained carbon fibers, mesh spacing 20 mm
A knitted fabric was obtained by weaving a woven cloth into a mesh. Bisphenol A type epoxy resin (produced by Yuka Shell Co., Ltd., trade name Epicoat 1001) and dicyandiamide (produced by Nippon Carbide Co.) as a curing agent were dissolved in a mixed solvent of methanol / methyl ethyl ketone to prepare a resin solution of about 50% by weight. . The knitted fabric having the above-mentioned simulated weave structure was dipped in this resin solution, dried and then cured at a temperature of 180 ° C. for 2 hours to obtain a mesh-shaped reinforcing material. The fiber volume content of the reinforcing material is about 40% by volume.

Early strength Portland cement / fine aggregate (maximum diameter of aggregate 20
mm) = 1/2 (weight ratio), and water / early strength Portland cement = 0.26 was prepared as a cement composition.

Then, a prestressed concrete sheet pile test piece having a sectional structure as shown in FIG. 3 was produced. That is,
Prestressed steel stranded wire (SWPR7A, diameter 9.3 mmφ) (22) in both sides of a test piece 2 m long, 500 mm wide, and 80 mm thick
, And deformed rebar D13 (23) were alternately arranged with a cover of 22 mm at intervals of about 120 mm. Further, the mesh-like reinforcing material (21) was arranged on one surface layer of the test piece with a one-ply cover of 3 mm. After placing the cement, steam curing,
A test piece was prepared by introducing prestress in 2 days of material cooling.

Comparative Example 1 A test piece was prepared in the same manner as in Example 1 except that a wire mesh having a wire diameter of 1.6 mm and a mesh interval of 25 mm was used instead of the mesh-shaped reinforcing material.

Comparative Example 2 A test piece was prepared in the same manner as in Example 1 without filling the mesh-shaped reinforcing material.

Example 2 A test piece was produced in the same manner as in Example 1 except that deformed bar D6 was used instead of deformed bar D13.

Comparative Example 3 A test piece was prepared in the same manner as in Comparative Example 1 except that deformed bar D6 was used instead of deformed bar D13.

Comparative Example 4 A test piece was prepared in the same manner as Comparative Example 2 except that deformed bar D6 was used instead of deformed bar D13.

Example 3 In the same manner as in Example 1 without using the prestressed steel twisted wire and deformed bar D13, a test piece in which only the mesh-shaped reinforcing material was arranged was prepared.

Comparative Example 5 A test piece in which only a wire mesh was arranged was prepared in the same manner as in Comparative Example 1 without using the prestressed steel twisted wire and the deformed bar D13.

Bending test of the test piece obtained in each Example and Comparative Example,
The distance between spans was 1 m, and the load was applied with two points at three equal points.
The crack width was measured using a crack meter. Then, when the load corresponding to the crack width of 0.05 mm was examined, the results shown in the table were obtained. The crack width (mm) and load (ton) of the test pieces obtained in Example 3 and Comparative Example 5 were also measured.
Fig. 4 shows the relationship with f).

In the table, PC indicates a stranded wire of prestressed steel, WM indicates a wire mesh, and CF indicates a carbon fiber mesh reinforcing material having a simulated weave structure.

From the table and FIG. 4, in the case where the test piece in which the mesh-like reinforcing material is arranged on the surface layer portion of the concrete member has a smaller crack width than the test piece in which the wire mesh, the deformed bar and the like are arranged and there is no reinforcing bar (Example) Even in 3), the crack width is less than the allowable value specified in JIS A 5326.

JIS A 5326 specifies that the cross-sectional proof stress is at least twice the cracking moment (load 9.4 tonf), but the test pieces obtained in each Example and Comparative Example are specified. It had a proof stress more than the load. Further, the test piece (Example 3) in which the mesh-shaped reinforcing material was arranged on the surface layer portion of the concrete member without disposing the reinforcing bar had sufficient rigidity.

Further, the weight of the reinforcing material was about 4 kg for the deformed bar D13 and 0.6 kg for the wire mesh per 0.1 m of the length of the prestressed concrete sheet pile, whereas it was 0.14 kg for the mesh reinforcing material.

[Brief description of drawings]

FIG. 1 is a structural diagram showing an example of a simulated weave structure of the present invention, and FIG. 2 is a schematic sectional view showing an example of a concrete structure of the present invention. FIG. 3 is a sectional view showing a sectional structure of a prestressed concrete sheet pile test piece in Example 1, and FIG. 4 is a graph showing results of Example 3 and Comparative Example 5. (1) ... warp fiber, (2) ... weft fiber, (11) (2
1) …… Reinforcement material, (12) …… Concrete member, (13)
...... Concrete structure

Claims (2)

[Scope of utility model registration request] 1. A concrete structure characterized in that a reinforcing material, in which reinforcing fibers are knitted into a mesh-shaped woven cloth weave and is integrated with a resin, is arranged in a surface layer portion of a concrete member. 2. The concrete structure according to claim 1, wherein the reinforcing fibers are carbon fibers.