JPH04258465A - Roof slab and manufacturing method therefor - Google Patents

Abstract

PURPOSE:To provide a roof slab that is excellent in thermal insulating effect by eliminating surplus water during hardening of concrete and by decreasing thereby contraction coefficient of the hardened concrete. CONSTITUTION:A roof slab 11 is manufactured by providing concrete layer 4 as a part of an integral body of the slab to the surface of a water permeable board 3 that is made up by sticking water permeable layers 8 and 9 to the surface and the under surface of a net 7 formed of hairlines and is made hollow with spaces left in meshes of the net, and the water permeable board 3 of the roof slab is placed on a horizontal form 1 equipped with numerous weepholes 2. Then ready-mixed concrete is poured thereupon.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete roof slab and a method for manufacturing the same.

0002

2. Description of the Related Art Generally, the concrete is exposed on the lower surface of a concrete roof slab, so the insulation effect is low and it tends to be uncomfortable to live in. Moreover, since the top surface of the roof slab is in contact with the atmosphere, it is most susceptible to changes in weather conditions, and if cracks form, rain can leak. As a countermeasure to this problem, hard-mixed concrete is used to prevent excess water from forming during hardening.
However, even in that case, it is difficult to reliably remove excess water, and from a microscopic perspective, water droplets remain inside, making the entire structure spongy, increasing the shrinkage coefficient, and easily causing cracks. . To quickly remove excess water,
It is also possible to provide a large number of drainage holes in the formwork, but in that case, the mortar components in the concrete will also escape, resulting in a decrease in strength.

0003

[Object of the invention] The first invention aims to provide a roof slab with high heat insulation effect, and the second invention aims to promptly remove surplus water during hardening and improve the effectiveness of the resulting concrete. The purpose is to reduce the shrinkage coefficient.

0004

[Structure of the Invention] The first invention is to fix a water-permeable layer to the upper and lower surfaces of a net made of fine wires, and integrally form a concrete layer on the upper side of a hollow-shaped water-permeable plate that leaves spaces within the mesh. This is the roof slab installed.

[0005] The second invention is a hollow-shaped water-permeable structure in which a water-permeable layer is fixed to the upper and lower surfaces of a net made of thin wires on a horizontal formwork having a large number of drainage holes, leaving spaces in the mesh of the mesh. This is a method of manufacturing roof slabs in which a board is placed on top of which fresh concrete is poured.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, which shows a cross section, numeral 1 denotes a formwork made of plywood and provided with a large number of drainage holes 2. When using a plywood board with a thickness of 10 mm as formwork 1, drain hole 2
5 mm in diameter can be arranged in a grid pattern at a pitch of 100 mm. Of course, they may be arranged in a staggered manner. A water-permeable plate 3 is placed on the formwork 1, and a concrete layer 4 is formed thereon. The water-permeable plate 3 has a mesh 7 in the center that combines vertical lines 5 and horizontal lines 6, and water-permeable layers 8 and 9 are fixed to the upper and lower surfaces of the mesh 7, creating spaces 10 that communicate with each other in the mesh of the mesh 7. ing. Vertical line 5 and horizontal line 6 have a diameter of 2 to 3
Using plastic wires of 5 mm in diameter, the pitch is 5~
The net 7 is formed by arranging them in a grid pattern of 10 mm and integrating them by adhesive. As the water-permeable layers 8 and 9, urethane foam with a thickness of 1 to 2 mm and in which fine bubbles are connected is used, and this is adhered to the net 7 to form the water-permeable plate 3 with a thickness of 5 to 7 mm. The concrete layer 4 is combined with the permeable plate 3 to form an integral roof slab 11. The net 7 may be formed by weaving the above-mentioned vertical lines 5 and horizontal lines 6.

[0007] To make the roof slab 11, a formwork 1 is supported horizontally, a permeable plate 3 is laid on it, and ready-mixed concrete is poured on top of it. Then, as the ready-mixed concrete hardens, the internal water drops, quickly enters the space 10 through the upper water-permeable layer 8, and then falls downward through the water-permeable layer 9 and the drain hole 2. In this way, excess water is quickly removed during concrete hardening.

FIG. 2 is a schematic vertical cross-sectional view of a test device for checking the water permeability of a water-permeable formwork, and corresponds to a part of the cross section of a box-shaped container. I in the figure shows the case where a general formwork without holes is used as the formwork 1, and II shows the case where the formwork 1 has a drainage hole 2 with a diameter of 5 mm.
III shows a case where a perforated formwork having a pitch of 00 mm is used, III a perforated formwork having a tapered part with a diameter of 10 mm at the upper end in the upper half, and IV a formwork of the present invention using a water-permeable plate 3. ing. The same amount of fresh concrete was poured into each formwork, and after a certain period of time (6 hours), water permeability, mortar components, and transparent water were measured.The results were as follows (in cc). I
II II
I IV water permeability
3.5 350.0 2
00.0 560.0 Mortar component 0.
5 195.0 155.0
31.0 Clear water 3.
0 155.0 45.
0 529.0

As is clear from the above test results, when a formwork using the water-permeable plate 3 of the present invention is adopted, the amount of water permeation is increased compared to when the formwork 1 is simply provided with a large number of drainage holes 2. Not only does this increase significantly, but the amount of permeation of mortar components also decreases.

0010

[Effect of the invention] According to the first invention, the concrete layer 4
Since the water-permeable plate 3 remains on the lower side, the heat retention effect is increased. In particular, the space 10 inside the water-permeable plate 3 improves heat retention performance. Second
According to the invention, since the water-permeable plate 3 also serves as a part of the formwork,
Excess water in the concrete layer 4 enters the space 10 from the wide upper water permeable layer 8, passes through the lower water permeable layer 9, and is discharged downward from the drain hole 2. This allows excess water to be quickly removed when the concrete hardens, resulting in a solid product and no water droplets remain within the concrete, making it easier to remove the excess water.
The shrinkage coefficient of the sheet is reduced, and the occurrence of cracks can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view when a roof slab is formed using a formwork.

FIG. 2 is a schematic vertical cross-sectional view of the test device.

[Explanation of symbols]

1 Formwork 2 Drain hole 3 Water-permeable board 4 Concrete layer 7 Net 8 Permeable layer 9 Permeable layer 10 Space 11 Roof slab

Claims (2)

[Claims] 1. A roof slab in which a concrete layer is integrally provided on the upper side of a hollow water-permeable plate with a water-permeable layer fixed to the upper and lower surfaces of a mesh made of fine wires, leaving spaces within the mesh. Claim 2: On a horizontal formwork having a large number of drainage holes,
A method for manufacturing a roof slab, in which a hollow water-permeable plate is placed on which a water-permeable layer is fixed to the upper and lower surfaces of a mesh made of fine wires, leaving spaces within the mesh, and ready-mixed concrete is poured onto the board.