JPH04296512A - Fiber reinforced material - Google Patents

Abstract

PURPOSE:To provide a fiber reinforced concrete rod having a high strength corresponding to its cross-section and being bearable with a large breaking loads even when the rod has a large diameter. CONSTITUTION:A fiber reinforced material 1 is constructed such that high strength such as carbon fiber or aramid fiber is aligned in one direction and then made into a rod-shape by allowing resin to be impregnated therein, and multiple circumferential grooves 2a-2c provided in the material end part, and further the depth of the circumferential grooves 2a-2c is made successively deeper to the material end part.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforcing material which is buried within a concrete structure and used as a reinforcing material particularly against tensile forces.

0002

[Prior Art] Recently, in concrete structures,
Various fiber materials are often used as reinforcing materials in place of steel. For example, high-strength fibers such as carbon fibers and aramid fibers are aligned in one direction using the pultrusion method, impregnated with resin, and made into rod shapes. Fiber reinforcement materials are known. Such fiber reinforcement materials exhibit durability and toughness that far exceed those of steel materials, so they are attracting attention as reinforcement materials for concrete.

[0003] However, this fiber material has a smooth surface and has difficulty adhering to concrete. For this reason, fiber reinforcing materials such as braiding multiple long fibers in the form of a braid are recommended.
The surface layer is made uneven, and this method is used to improve adhesion.

0004

[Problem to be Solved by the Invention] However, in conventional fiber reinforcement materials, the acting external force generally exhibits a behavior in which it is gradually transmitted from the fibers located in the surface layer to the fibers in the center, and therefore, the external force is generated. The stress is smaller in the center than in the surface layer, so that the fibers in the surface layer may break even before the fibers in the center reach their breaking limit. In other words, even if the outer diameter is increased in order to improve the breaking limit of the reinforcing material, the fibers in the surface layer will quickly break before the set breaking load, and the outer diameter of the reinforcing material will simply increase. Even if the diameter was increased, the fibers in the center did not contribute to improving the strength. In other words, the outer diameter dimension, that is, the cross-sectional area, does not correlate proportionally with the improvement of strength performance and has a limit, making it impossible to fully demonstrate the inherent strength performance of the fiber material. .

[0005] At present, the outer diameter of the fiber material is about 10 mm, which is the limit at which the inherent strength performance of the fiber material can be exhibited in a relatively wasteful manner. In order to obtain a fiber reinforcement material with higher strength, a large number of single wires with an outer diameter of about 5 mm are twisted together, but in such a twisted structure, gaps are created between the single wires. Unavoidable, the outer diameter becomes extremely large, and
It was not possible to fully demonstrate the strength of the fibers.

The present invention was made in view of the above background, and it is possible to exhibit strength performance commensurate with the cross-sectional area even when the diameter is increased, and it is possible to significantly improve the breaking load. The purpose is to provide a high-strength fiber reinforcing material.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a fiber reinforcing material formed into a rod shape by impregnating high-strength fibers such as carbon fibers and aramid fibers with a resin, in which tensile force is input. The material is characterized in that a plurality of concave and convex portions are arranged in parallel at intervals in the direction of the material axis.

[0008] Furthermore, the depth of the recesses arranged in parallel is gradually increased toward the end of the material.

[0009]

[Operation] Regarding the operation of the present invention, a flange is defined between adjacent concave and convex portions, and this flange receives an input tensile force. The external force received by the flange generates stress at the bottom of the recess, that is, at the center deeper than the surface layer of the fiber reinforcement, and the generated stress can be directly borne by the center of the fiber reinforcement. . In addition, since the depth of the recess is deeper on the material end side, stress is generated in the center of the fiber reinforcement material on the material end side, and the fiber reinforcement material gradually increases from the material end side along the material axis direction. The burden of generated stress can be distributed toward the surface layer side of the fiber reinforcement material, and the stress distribution generated in the fiber reinforcement material can be made uniform over the entire cross section.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a partially cutaway side view showing a preferred embodiment of the fiber reinforcement material according to the present invention.

This fiber reinforcing material 1 is made into a rod shape by aligning high-strength fibers such as carbon fibers and aramid fibers in one direction by the pultrusion method and impregnating them with resin. Basically, uneven portions, specifically circumferential grooves 2a to 2c, are provided in multiple stages on the circumferential surface of the material end, and the depths of these circumferential grooves 2a to 2c are sequentially set toward the material end. A configuration with deeper grooves is adopted, and in this embodiment, the circumferential grooves 2a to 2c are provided in three stages.

[0012] The circumferential grooves 2a to 2c are formed using the fiber reinforcing material 1.
It is formed by an appropriate method such as cutting the peripheral surface with a lathe.

FIG. 2 shows an example in which the material shown in FIG. 1 is applied to a concrete structure as a tendon material, and also schematically shows the stress distribution in each part.

This application example uses a cylindrical fixing sleeve 3.
This is an example in which a fixing sleeve 3 is placed on the end of the fiber reinforcing material 1, and a grouting material 4 such as resin or mortar is filled in the gap therebetween. Of course, during fixing, a tensile force T is applied to the fiber reinforcing material 1. In this case, due to the action of the tensile force T, the fixing nut 5 meshed with the outer circumferential threaded portion of the fixing sleeve 3 comes into contact with the concrete body 6, and the fixing sleeve 3 is locked to the concrete body 6.

According to such a structure, in the fiber reinforcing material 1, the spaces between adjacent circumferential grooves 2a to 2c provided in multiple stages form flanges 12a to 12c, and the flanges 12a to 12c
is subjected to the tensile force T, and stress is generated at the bottoms of the circumferential grooves 2a to 2c, that is, at the center portions 20a to 20c of the fiber reinforcing material 1. That is, the tensile force T received by the flanges 12a to 12c is applied to the bottoms of the circumferential grooves 2a to 2c,
That is, the central portions 20a to 20 deeper than the surface layer of the fiber reinforcing material 1
c, and the generated stress can be directly borne by the central portions 20a to 20c of the fiber reinforcing material 1. Moreover, since the depth of the circumferential grooves 2a to 2c is deeper on the material end side, the central part of the fiber reinforcement material 1 is formed on the material end side.
While generating stress at 0a to 20c, the stress generated in the fiber reinforcement material 1 can be gradually distributed from the material end side toward the surface layer side of the fiber reinforcement material 1 along the material axis direction, thereby reducing the stress generated in the fiber reinforcement material 1. The distribution can be made uniform over the entire cross section. Therefore, even if the diameter is increased, strength performance commensurate with the cross-sectional area can be exhibited, the breaking load can be significantly increased, and high strength can be obtained.

Further, according to the above structure, conventional methods such as a twisted structure for obtaining high strength are unnecessary, and labor can be saved in manufacturing and constructing an ultra-high strength member.

Although the application example shown in FIG. 2 is constructed with the fixing sleeve 3 interposed, the present invention is not limited to this. That is, it may be directly buried in the concrete frame 6 without using the fixing sleeve 3, or may be combined with anchor bars as appropriate, and it goes without saying that similar effects can be achieved in such applications.

[0018] In the above embodiment, the uneven portion is formed by a circumferential groove cut from the surface of the fiber material.
The surface of the fibrous material may be provided with a fibrous material such as carbon fiber in multiple stages in the circumferential direction and in the axial direction of the material to form an uneven portion. be effective.

[0019]

Effects of the Invention As explained in detail in the embodiments above, according to the fiber reinforcing material of the present invention, a flange is formed between adjacent uneven portions, and the tensile force inputted by the flange is received. It turns out. The external force received by the flange generates stress at the bottom of the recess, that is, at the center deeper than the surface layer of the fiber reinforcement, and the generated stress can be directly borne by the center of the fiber reinforcement. . In addition, since the depth of the recess is deeper on the material end side, stress is generated in the center of the fiber reinforcement material on the material end side, and the fiber reinforcement material gradually increases from the material end side along the material axis direction. The burden of generated stress can be distributed toward the surface layer side of the fiber reinforcement material, and the stress distribution generated in the fiber reinforcement material can be made uniform over the entire cross section. Therefore, even if the diameter of the fiber reinforcing material is increased, strength performance commensurate with its cross-sectional area can be exhibited, the breaking load can be significantly increased, and high strength can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of application of the tension material shown in FIG. 1 and explaining its stress distribution.

[Explanation of symbols]

1 Fiber reinforcement material 2 Circumferential groove

Claims (2)

[Claims] Claim 1: In a fiber reinforcement material made of high-strength fibers such as carbon fibers or aramid fibers impregnated with resin and formed into a rod shape, a plurality of fiber reinforcements are provided at intervals in the axial direction of the material in the part where tensile force is input. A fiber reinforcement material characterized by having uneven parts arranged side by side. 2. The fiber reinforcing material according to claim 1, wherein the depths of the recesses arranged in parallel are gradually increased toward the end of the material.