JPS632867A - Hybrid type fiber reinforced lightweight concrete structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a lightweight, high-strength hybrid fiber-reinforced lightweight concrete structure used for precast concrete for outer walls of architectural structures, curtain walls, etc.

"Conventional Technology" In recent years, there has been an increasing demand for lightweight and strong structural concrete materials. Among these, as a means of reducing weight, the application of lightweight concrete instead of ordinary ordinary concrete has been implemented, but in the case of lightweight concrete,
The shrinkage stress caused by the humidity distribution within the cross section of the member is greater than that of ordinary concrete, and the tensile strength is also lower than that of ordinary concrete, so cracks tend to occur on the surface of the plate and its durability is inferior to that of ordinary concrete. There is.

Therefore, as a solution to these problems, short fibers such as carbon fibers and steel fibers are randomly mixed into lightweight concrete in three dimensions to increase the bending strength and create lightweight and strong structural concrete. Fiber-reinforced concrete is known as a material.

``Problems to be solved by the invention'' However, conventional fiber-reinforced concrete has a length of 5 to
Because the structure consists of short reinforcing fibers of about 40 mm uniformly dispersed in the concrete in a randomly oriented state (three-dimensional direction), the effectiveness of the fibers against tensile force in a specific direction is low, causing shrinkage cracks on the surface. Since it is not possible to completely suppress this, it is necessary to mix a large amount of short fibers (3 by volume)
5%), which resulted in problems such as high cost and reduced workability.

The present invention has been made in view of the above-mentioned problems, and by mixing short fibers and mesh-like fibers in combination into lightweight concrete, which is the main body of the structure, to create a hybrid fiber-reinforced concrete material, The purpose of this project is to provide a hybrid fiber-reinforced lightweight concrete that can reduce the amount of fibers mixed in, reduce costs, and improve workability.

``Means for Solving the Problems'' In order to solve the above-mentioned problems, the present invention provides a concrete structure in which the structure body receiving the bending moment is made of lightweight concrete with a specific gravity of 0.8 to 1.6. Short fibers made of reinforcing fibers such as carbon fibers, glass fibers, aramid fibers, and synthetic fibers are mixed in a three-dimensional random manner at a volume ratio of 1.0 to 0.2%, and the fibers made of the reinforcing fibers are It is characterized in that the mesh-like fibers are embedded in the structure main body in the direction in which the tensile force is applied at a volume ratio of 0.1 to 0.02%.

"Function" According to the present invention, by replacing a portion of the short fibers mixed three-dimensionally randomly into the concrete structure with mesh-like fibers arranged in the stress direction, the effectiveness ratio of the fibers against bending strength is improved. However, the bending strength is ensured by the small amount of fiber.

"Example" Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a hybrid fiber-reinforced lightweight concrete structure showing one embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view (X-X ray section) showing the first embodiment. It is.

In these figures, the symbol A is a hybrid fiber-reinforced lightweight concrete structure (hereinafter simply referred to as the "structure"), and the interior of the structure body l is made of lightweight concrete with a specific gravity of 0.8 to 1.6. Short fibers cut to a predetermined length 2.2. ... are mixed three-dimensionally randomly at a volume ratio of 1.0 to 0.2%, and near the lower surface in the plate thickness direction, in the width direction (first
It has a structure in which mesh-like fibers 3 extending in the horizontal direction (vertical direction in the figure) and longitudinal direction (horizontal direction in FIG. 1) are buried at a volume ratio of 0.1 to 0.02%.

For example, when high tensile strength is required as the material for the mesh-like fibers 3 in FIGS. Strength-reinforcing fibers are used, and when a very high tensile strength is not required, synthetic fibers such as vinylon, polyethylene, polypropylene, etc. are used. Then, the mesh-like fiber fI113 is made of a different type, for example, a material having a high tensile strength in the direction of the main reinforcement (horizontal direction in FIG. 1) (for example, carbon fiber,
It is preferable to use small aramid fibers (such as vinylon, polyethylene, polypropylene, etc.) in the direction of the distribution muscles, since this allows more effective use of the fibers and further reduces costs. It goes without saying that the size of the lattice of the mesh-like fibers 3 may be changed as appropriate depending on various purposes of use.

The short fibers 2 are intended to improve the shear strength and impact strength of the structure A.1. As the material, a material obtained by cutting the reinforcing fibers used for the mesh-like fibers can be used.

To form this structure A, short fibers 2, 2. Lightweight concrete mixed three-dimensionally at random may be cast in layers, and the mesh-like fibers 3 may be thrown in between.

In the structure A having this configuration, short fibers 2, 2 . By replacing the negative part of ... with mesh fibers 3 arranged in the stress direction (i.e., width direction and longitudinal direction), the mesh fibers 3 can 100% effectively counter the bending stress acting on the structure A. This not only improves the bending strength of the structure A, but also efficiently suppresses cracks on the surface of the structure body 1. In addition, the short fibers 1f2, 2.・・・
- can increase the shear strength and impact strength of structure A.

Therefore, the mesh-like fibers 3 and the short fibers 2.2. ...and act efficiently and effectively against tensile force and shearing force, respectively, so compared to conventional fiber-reinforced concrete structures in which short fibers are mixed in the entire cross section, a small amount of fiber can achieve a specified strength. is ensured, costs can be reduced, and workability can be improved.

Next, second to fifth embodiments will be shown using FIGS. 3 to 6. In these figures, the same elements as those shown in the first embodiment are denoted by the same reference numerals and their explanations will be omitted.

FIG. 3 shows the second embodiment, and is a longitudinal cross section (X--X line cross section) of FIG. 1. In the figure, inside the structure main body l, minor 1a base 2, 2. ... are mixed three-dimensionally at random, and in the width direction (vertical direction in Figure 1) and longitudinal direction (horizontal direction in Figure 1) of this structure main body I near the top and bottom surfaces in the plate thickness direction. It has a structure in which mesh-like fibers 3, 3 extending from the bottom are buried. FIG. 4 shows the third embodiment, and is a longitudinal section (X-X
Linear cross section). In the figure, short fibers 2, 2. ... are mixed in a three-dimensional random manner, and mesh-like fibers 2, 2, . ...is buried in the structure. FIG. 5 shows a fourth embodiment, and is a longitudinal cross section (X-X line cross section) of FIG. 1. In the figure, short fibers 2, 2. ... are mixed in a three-dimensional random manner, and in the width direction of this structure body (vertical direction in Fig. 1) near the lower surface in the plate thickness direction.
It has a structure in which mesh-like fibers 3.3 extending in the longitudinal direction (horizontal direction in FIG. 1) are buried doubly. FIG. 6 shows a fifth embodiment, and is a longitudinal section (YY line view) of FIG. 1. In the figure, short fibers 2, 2. ... are mixed three-dimensionally at random, and extend in the width direction (vertical direction in Fig. 1) and longitudinal direction (horizontal direction in Fig. 1) near the top and bottom surfaces in the plate thickness direction. mesh-like fibers 3.3,
A mesh-like Qga for reinforcement connects these in a truss shape.
3a, 3a, . . . are buried in the structure.

In the second to fifth embodiments described above, the specific gravity of the lightweight concrete is 0.8 to 1.6, and the volume ratio of the short fibers 2 mixed into the structure body 1 is 1.0 to 0. .2%
, and the volume ratio of the embedded mesh-like fibers is 0.1 to
The composition is 0.02%. Therefore, the second
~The fifth embodiment also has the same functions and effects as the first embodiment.

Note that the following combinations of materials for the short fibers 2 and the mesh-like w&p 3 used in the above embodiments are possible.

Note that the material combinations are not limited to those listed in the table above.

Further, in this example, in order to further reduce the weight, a structure may be adopted in which foamed polystyrene, a honeycomb core, etc. are disposed in the middle part of the structure main body 1 in the thickness direction.

The embodiments of the present invention have been described above, but the present invention includes
It is not limited to the above. For example, in each of the above Examples, carbon fiber, glass fiber, aramid fiber, etc. were exemplified as high-strength reinforcing fibers, but carbon fibers equivalent to these fibers (
For example, ceramic fibers, metal fibers, etc.) may be used.

Furthermore, in each of the above embodiments, Structure A was explained as an example of a hybrid fiber-reinforced lightweight concrete structure. Of course, it can also be applied to members.

"Experimental Example" Hereinafter, the relationship between the fiber content ratio and the bending strength when the concrete structure of the present invention is reinforced with aramid short fibers and vinylon mesh fibers will be explained using Appended Tables I to 4.

Here, Table 1 shows the properties of fibers, Table 2 shows the properties of aggregate, Table 3 shows the mixture, experimental results, and calculated values for concrete structures, and Table 4 shows the properties of the aggregate. It is a chart showing the relationship between the fiber mixing ratio pt and the ultimate bending strength σ calculated using the bending ultimate strength formula of the Architectural Institute of Japan/Reinforced Concrete Structure Calculation Standards, assuming that the fibers are tensile reinforcing bars.

The cement used was early strength Portland cement.
The test material regulation was on the 14th, and the test method was in accordance with JISR5201.

In Table 3, the bending strength when only aramid short fibers are mixed is 38°9 to 49.3 at a fiber mixing rate of 0.5%.
kg/am', and in Table 4, Pt is 0.06
% or less, and the effectiveness of the fiber is low. - On the other hand, from Table 3, the ratio between the calculated value and the measured value regarding the amount of increase in bending strength due to the arrangement of vinylon mesh fibers is 0.719 ~
With a value of 0.867, the reinforcing effect of vinylon mesh fibers is quite large.

"Effects of the Invention" As explained above, the present invention provides carbon fiber, glass fiber, Short fibers made of reinforcing fibers such as aramid fibers and synthetic fibers are mixed in a three-dimensional random manner at a volume ratio of 1.0 to 0.2%, and mesh-like fibers made of the reinforcing fibers are mixed in a volume ratio of 0.1 to 0.2%. Since the fibers are buried in the direction in which the tensile force of the structure body is applied at a volume ratio of 0.02%, the effective ratio of the fibers to the bending strength is improved, and the bending strength is ensured by a small amount of fibers, and the fibers' The amount used can be reduced, and compared to lightweight concrete in which only short fibers are randomly mixed in three dimensions, costs can be reduced and workability can be improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional plan view of a hybrid fiber-reinforced lightweight concrete structure of the present invention, FIG. 2 is a cross-sectional view taken along the line X--X of FIG. 1, and FIG. 3 is a cross-sectional view of the first embodiment. FIG. 4 is a cross-sectional view taken along the line X--X in FIG. 1 showing a second embodiment of the present invention, FIG. 4 is a cross-sectional view taken along line X-X in FIG. xx sectional view of FIG. 1 showing the fourth embodiment,
FIG. 6 shows a fifth embodiment of the present invention and is a sectional view taken along the Y-Y line in FIG. 1. A...Hybrid fiber reinforced lightweight concrete structure (structure), ■...Structure body, 2.
...short fiber, 3...mesh-like fiber.

Claims (1)

[Claims] The structure body that receives the bending moment has a specific gravity of 0.8 to 1.
Carbon fiber, glass fiber, aramid fiber,
1.0 to 0.2 short fibers made of reinforcing fibers such as synthetic fibers
The mesh fibers made of the reinforcing fibers are mixed three-dimensionally randomly at a volume ratio of 0.1 to 0.
A hybrid fiber-reinforced lightweight concrete structure characterized by being buried in the direction in which the tensile force of the structure body is applied at a volume ratio of 0.02%.