JPH0588334B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a lightweight, high-strength fiber-reinforced concrete structure.

"Prior Art" In recent years, there has been an increasing demand for lightweight and strong structural concrete materials. Among these, as a means of weight reduction, instead of ordinary concrete,
Lightweight concrete has been applied, or a sandwich structure in which honeycomb or foamed polystyrene is sandwiched between lightweight concrete or ordinary concrete has been implemented, but in the case of lightweight concrete, the moisture distribution within the cross section of the member Because the resulting shrinkage stress is greater than that of ordinary concrete, and the tensile strength is lower than that of ordinary concrete, cracks tend to occur on the surface of the slab, and its durability is inferior to that of ordinary concrete.

Furthermore, even if the concrete is made of ordinary concrete, the surface plate of a sandwich structure with honeycomb or styrofoam sandwiched in between has a small thickness, so there is a problem in durability.

Therefore, as a result of intensive research to solve these problems, the present applicant et al. have developed a unidirectional continuous material made of carbon fibers, steel fibers, etc. along the direction in which tensile force is applied in lightweight concrete or ordinary concrete. They came up with the idea that by embedding long fibers, it would be possible to improve the bending strength and provide a lightweight and strong concrete material.

``Problems to be solved by the invention'' However, conventional fiber reinforcement of concrete
Because the structure consists of short reinforcing fibers with a length of about 20 to 40 mm dispersed in concrete in a two-dimensional random manner, the reinforcing efficiency is poor and shrinkage cracks on the surface cannot be completely suppressed. There is a point.

In addition, in the case of structures in which continuous long fibers are buried in one direction in lightweight concrete or ordinary concrete, in the case of bent materials, the long fibers are effectively utilized in the direction of the main force reinforcement, but in the direction of the distribution reinforcement. The problem is that it is not used effectively and costs are high.

"Means for Solving the Problems" The present invention effectively solves the problems described above, and provides a heat insulating material that is lighter than these boards between two boards made of lightweight concrete or ordinary concrete. A plurality of first long fibers, each of which is continuous in one direction, are buried at intervals in the direction of the distribution reinforcement in the direction of the main reinforcement of the board while sandwiching the layers together, and in the direction of the distribution reinforcement of the board, It is characterized in that a plurality of second long fibers, each of which has a lower tensile strength than the first long fibers and which are continuous in one direction, are buried in parallel so as to intersect with the first long fibers.

"Action" According to the present invention, two types of long fibers, the first long fibers arranged in the direction of the main force reinforcement and the second long fibers arranged in the direction of the distribution reinforcement, act on the lightweight concrete. Or, since it is used to reinforce ordinary concrete, fibers can be used effectively against tensile forces, reducing costs.In addition, these long fibers can suppress shrinkage cracks on the board surface. As a result, its durability can be increased and its applicability to weight reduction can be improved.

Further, the fiber-reinforced concrete structure of the present invention has the advantage that the heat insulation effect can be improved due to the heat insulation layer being lighter than a board made of lightweight concrete or ordinary concrete.

"Example" Hereinafter, an example in which the present invention is applied to a deck slab that receives bending moments in two directions in the thickness direction will be described with reference to the drawings.

First, with reference to FIGS. 1 and 2, a fiber-reinforced concrete floor slab (hereinafter simply referred to as floor slab) S of a first embodiment will be described. This floor slab S has a basic structure in which a heat insulating layer C, which is lighter than the boards A and B, is interposed between two lightweight concrete or ordinary concrete boards A and B facing each other. There is.

Next, to explain these details, boards A and B are formed into a rectangular shape mainly made of lightweight concrete or ordinary concrete, and inside them there are bars extending in the direction of the main strength reinforcement of boards A and B (horizontal direction in Figure 1). The first long fibers 1 extend and are parallel to each other at intervals in the direction of the distribution muscle (vertical direction in FIG. 1), and the main fibers extend in the direction of the distribution muscle while intersecting these first long fibers 1. The second long fibers 2 arranged in parallel at intervals in the direction of the fibers are embedded in a mesh shape.

These first and second long fibers 1 and 2 are formed into linear continuous fibers whose lengths are equal to the lengths of the boards A and B in the direction of the main force and the length in the direction of the distribution muscles. In addition, the first long fiber 1 is
It is made of reinforcing fibers having a higher tensile strength than the second long fibers 2. Here, as the material of the first long fiber 1, for example, high-strength reinforcing fiber having extremely high tensile strength and elastic modulus such as carbon fiber, glass fiber, or aramid fiber is used, and the second long fiber As the material of the fiber 2, synthetic fibers such as vinylon, polyethylene, polypropylene, etc. are used. It goes without saying that the mesh size of the lattice of these long fibers 1 and 2 can be changed as appropriate depending on various purposes of use.

In addition, to explain the heat insulation layer C, in this embodiment, it is composed of an air layer formed by a corrugated steel plate (honeycomb plate) 3, and this honeycomb plate 3 protrudes from each top of the corrugation and extends inside the boards A and B. It is integrated into these boards A and B by buried studs 4.

To form this floor slab S, for example, the long fibers 1 and 2 are arranged in a mesh shape in the formwork of the board A to be formed, lightweight concrete or ordinary concrete is poured, and a honeycomb is placed on top of this. plate 3
After arranging the board B, lightweight concrete or ordinary concrete may be cast thereon to integrate the board B with the board A via the honeycomb plate 3.

In the floor slab S with this configuration, the long fibers 1 and 2 arranged in the stress direction of the floor slab S (that is, the main force reinforcement direction and the distribution reinforcement direction) are 100% effective against the bending stress acting on the floor slab S. To counter this, the bending strength of the floor slab S is improved, and cracks on the surfaces of the boards A and B are efficiently suppressed. That is, in this floor slab S, the first long fibers 1 are arranged in the direction of the main force reinforcement, and the second long fibers 2 are arranged in the direction of the distribution reinforcement (long fibers with a lower tensile strength than the first long fibers 1). ), the two types of long fibers are used to reinforce lightweight concrete or ordinary concrete depending on the stress applied, so the fibers can be used effectively against tensile forces.
This makes it possible to reduce costs.

In addition, this product has a multi-layer structure with a sandwiched trench structure in which a heat insulating layer C is sandwiched between boards A and B, so it has the effect of improving heat insulating performance, and it also has the effect of improving heat insulation performance compared to conventional lightweight concrete etc. Compared to a single-structure precast panel, it also has the advantage of being lighter if its overall thickness is about the same.

Next, a floor slab T according to a second embodiment of the present invention will be explained with reference to FIG. 3. This floor slab T is basically the same as the floor slab S of the previous embodiment, but
In this embodiment, the heat insulating layer C is replaced with a honeycomb plate 3, and a polystyrene foam 6 is integrally sandwiched between the boards A and B via a connecting reinforcing bar 7.

In addition, in order to form this floor slab T, the long fibers 1 and 2 are arranged in a mesh shape within the formwork of the board B to be formed, the connecting reinforcing bars 7 are made to protrude, and lightweight concrete or ordinary concrete is poured. do. Next, after placing the Styrofoam 6 on the board B, placing the long fibers 1 and 2 on the Styrofoam 6 and pouring lightweight concrete or ordinary concrete, a floor slab T shown in FIG. 3 etc. is obtained. is formed.

Even in the floor slab T having such a configuration, the long fibers 1 and 2 act 100% effectively against the tensile force in the stress direction, improving the bending strength and efficiently covering the surfaces of the boards A and B. It is possible to suppress cracks in the material and improve its applicability to weight reduction.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above. for example,
Although carbon fibers, glass fibers, and aramid fibers are exemplified as high-strength reinforcing fibers in the above embodiments, other fibers equivalent to these fibers (eg, ceramic fibers, metal fibers, etc.) may also be used. Furthermore, in each of the above embodiments, floor slabs S and T were explained as examples of fiber-reinforced concrete structures, but the present invention is applicable not only to floor slabs but also to other architectural structural members and non-structural members. Of course, it is also possible to do so.

"Effects of the Invention" As explained above, the present invention has two boards made of lightweight concrete or ordinary concrete, in which a heat insulating layer that is lighter than these boards is integrally sandwiched between them, and A plurality of first long fibers each continuous in one direction are buried at intervals in the distribution muscle direction, and
In the direction of the distribution muscles of the board, a plurality of second long fibers that are continuous in one direction and have a lower tensile strength than the first long fibers are buried in parallel with each other, crossing the first long fibers. It has such excellent effects.

(a) Since the two types of long fibers are used to reinforce lightweight concrete or ordinary concrete depending on the stress applied, the fibers can be used effectively against tensile forces.

(b) The two types of long fibers have both the effect of suppressing shrinkage cracks on the surface of the board and the effect of improving tensile strength, and are 100% effective against a specific tensile force, so the amount of fiber used can be reduced. This makes it possible to reduce costs compared to lightweight concrete or ordinary concrete in which short fibers are mixed in the entire cross section.

(c) According to the above, cracks on the surface of lightweight concrete or ordinary concrete can be completely prevented, and the strength can be improved, and the applicability to weight reduction can be improved.

[Brief explanation of drawings]

1 and 2 show a first embodiment of the present invention, FIG. 1 is a plan view, and FIG. 2 is a plan view of FIG.
FIG. 3 is a cross-sectional view taken along a line showing a second embodiment of the present invention. S, T... Lightweight concrete or ordinary concrete floor slab, A, B... Board, C... Heat insulation layer, 1... First long fiber, 2... Second long fiber,
3...honeycomb plate, 4...stud, 6...
... Styrofoam, 7... Connection reinforcing bars.

Claims (1)

[Claims] 1 A heat insulating layer C, which is lighter than these boards A and B, is integrally sandwiched between board A and board B formed of lightweight concrete or ordinary concrete, and in the direction of the main reinforcement of boards A and B. , a plurality of first long fibers 1 that are continuous in one direction are buried at intervals in the direction of the distribution muscles, and a plurality of first long fibers 1 are buried in the direction of the distribution muscles of boards A and B, respectively. A fiber-reinforced concrete structure characterized in that a plurality of second long fibers 2 having low tensile strength and continuous in one direction are buried in parallel in a state where they intersect with the first long fibers 1.