JPS601463B2 - How to fix GRC - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for fixing GRC (Glass-woven Totally Reinforced Cement) for fixing window frame mounting brackets and various other materials.

Since GRC can be easily formed into thin but strong molded products, it has begun to be used for various indoor and outdoor equipment such as panels for walls, ceilings, roofs, floors, etc. In order to fix to other structural members such as panels, or to attach window frames, ventilation holes, etc., those members are placed in the formwork in advance and GRC is supplied to integrate them. GR
Bolts were secured through the holes shown in C. However, when using the direct spray method, which is a typical manufacturing method for GRC, these methods have disadvantages such as the formation of cavities, insufficient adhesion, or the shape of the parts that can be used is considerably limited, and the use of very specific parts. If only the village can be embedded in one piece or installed by drilling,
It had drawbacks such as poor workability, poor adhesion, and bolts and nuts that easily appeared on the surface.

The present invention prevents such drawbacks by forming a GRC, and while the GRC is uncured, a desired member is attached to the GRC.
This is a method of fixing a GRC, in which the GRC and the backing material are fixed by placing the GRC on top of the GRC and using tapping screws.

In the present invention, various members are placed on the GRC while the GRC is uncured, so that the surface of the GRC easily conforms to the shape of the various members, and also firmly adheres to the GRC because it is screwed into the GRC with self-tapping screws. It is something that will be done.

In addition, GRC is usually reinforced with chopped strands made by cutting glass strands to the desired length.
By screwing in while the RC is uncured, it can be screwed in as smoothly as if it were screwed into fiberboard such as wood, and the threads drilled in it will not be destroyed by weak force like in ordinary concrete. Extremely high pull-out strengths, typically greater than 200k9, can be generated.

In other words, threads are drilled in the GRC itself by screwing, glass fibers are arranged along the threads, and the GRC around the threads is compressed by screwing, so the threads have high strength after the GRC hardens. It is.

On the other hand, if the screws were placed in the formwork and GRC was sprayed, the arrangement of glass fibers and the GRC near the threads
Since the RC does not compress, the strength of the screw threads is still insufficient, and although it is possible to screw into ordinary concrete by using the self-tapping screws used in the present invention, there are glass fibers. Because there is no concrete, the threads of the concrete will break with a weak force, resulting in a weak tensile strength. Further, according to the present invention, various sections can be easily fixed at various locations on the GRC, and the design of the GRC can be improved. Furthermore, in the case of GRQ using chopped strands, it is also possible to pull out this screwed-in tapping screw and screw it in again. Especially when using a tapping screw with a double helix, it is possible to pull out and screw in this screw. It also has the advantage that the drop in pull-out strength due to one repetition is considerably small, and only the members can be replaced from the GRC after molding.

The present invention will be explained in more detail.

GRC that can be used in the present invention refers to cements such as boltland cement, alumina cement, and magnesia cement reinforced with glass fibers, or cements with fibers other than glass fibers such as gypsum, lime, various aggregates, and asbestos as needed. ,
It is a cement material containing pulp, resin, various additives, etc.

Especially chopped strands with a weight of 10 to 50 are 1 to 8W.
The GRC containing t% has good bonding properties with the tapping screw, and makes the pulling out resistance of the tapping screw extremely high. The materials to be fixed in the present invention include various members such as metal, plastic, and wood, such as picture frames such as window frames, outer frames of panels, linings, mounting hardware, reinforcing strips, and reinforcing frames.

The self-tapping screw of the present invention is a screw that can be threaded, and the height of the thread of a normal screw is generally 10 to 14 mm of the core diameter.
%, whereas the height of the thread is 20% or more of the core diameter. By setting the height to 20% or more in this way, the connection with the ORC becomes strong. However, 5
If it exceeds 0%, it is not preferable because the core becomes weak or screwing becomes difficult. Also, the number of threads is 1 inch (25.
4) 30 or less is preferable because the threads on the GRC side are less likely to collapse. In addition, it is preferable to use a screw with an outer diameter of 2 skins or more in terms of strength, and it is usually recommended to use a screw with 3 to 8 ribs.
It is preferable in terms of strength and resistance to pulling out from GRC.

In particular, among self-tapping screws, self-tapping screws with high and low double helix crests have good screwability and GRC
It is preferable that the pull-out resistance from the core is large, and the height of the high thread is 24 to 50% of that of the core, and the height of the low thread is 10 to 22%.
It is preferable to use self-tapping screws.

When such a double-helical tuft pin screw is used, it is possible to remove the screw after the GRC has hardened and tighten it again to 0 degrees, which has the advantage of widening the range of applications.

The GRC is molded into a desired shape by a manufacturing method such as a premix method or a direct spray method.

In the case of a molded object with a specific shape such as a panel, spraying directly onto the formwork can increase the strength of GRC.
Although preferred in terms of workability, in the case of simply molded objects such as flat plates, corrugated plates, pipes, C-shaped plates, L-shaped plates, and U-shaped tubes, conventional methods such as paper-making methods, extrusion molding methods, and centrifugal molding methods are preferred. Various molding methods from 0 can be used. However, in the case of papermaking methods that tend to result in low density, it is preferable from the viewpoint of drawing resistance to increase the density by high-pressure pressing or the like. The GRC molded in this manner has various parts as described above arranged inside the uncured 5.

It is preferable to bring this into close contact with the GRC by its own weight or by applying pressure. It is preferable to carry out this process immediately after the cement material starts to set, when the GRC is slightly deformed when pressed with a finger, and it is preferably carried out as soon as the GRC flows due to the weight of the member and abnormal deformation occurs. I don't like that. In addition, on the other hand, the G
Even after RC is cured, adhesion tends to be insufficient. For this reason, it is usually preferable to carry out this step during a period in which the desired backing material does not deform under its own weight, and the surface of the GRC is slightly deformed by weak pressure applied by human power and comes into close contact with the member. This is, for example, early strength boltland cement (C/S) containing 5M% of chopped strands of 25%.
/1, W/C=0.3), after mortar thickening,
Within 4 hours, usually between 30 minutes and 2 hours.

In addition, in cases where there is little or no need for deformation of the GRC, such as when the member has a flat surface and the surface of the GRC has been smoothed with a trowel, etc., during the period when the tapping screw in the next process can be screwed in, It is sufficient to arrange the members on the ORC.

Next, the member is fixed to the GRC using self-tapping screws.

Although this step is carried out while the GRC is still uncured, it is preferable to carry it out at the same time as the previous step or when the curing has progressed, as this will give better tightening. For this reason, it is usually preferable to screw in manually or with an electric screwdriver after it has hardened to the extent that it does not deform much even when pressed with fingers.

Depending on the composition of each GRC, this can be done by screwing in while the GRC is uncured and can be screwed in with a self-tapping screw, but it is preferable to do this while the compressive strength of the GRC is 10 kg/or less. This makes it easy to screw in, provides high resistance to pulling out, and allows for sufficient tightening. In particular, it is preferable to harden the cement material after it has started setting, so that it can be easily squeezed in afterwards.
Specifically, in the case of GRC shown in the previous step, it is preferable to carry out the process approximately 2 to 4 hours after mortar kneading.

Next, explanation will be given based on an example.

In each test example, early strength boltland cement (manufactured by Mitsubishi Mining Cement Co., Ltd.) was mixed with C/S = 1/1 and W/C = 0.3, and glass fiber 37 skin length chopped strands (UK) were made by direct spraying. Product name “Cem-” manufactured by Pilkington
A test piece containing 5M% of ``FIL'') was sprayed onto a formwork of length 1, middle 10 ribs and thickness 35 side in a room at 25:00, and the surface was smoothed with a trowel. A cut piece of a sash for a window frame (a H-shaped aluminum piece with a 45 side contact surface with the GRC x 5 ribs, a thickness of 1.2 mm, a height of 15 ribs, and a hole for a screw in the center of the contact surface) and the outside. Type 1 JIS tapping screw (hereinafter referred to as screw A) on the 4th side, manufactured by Nippon Drivit Co., Ltd., product name Hi
- Using S type screws (hereinafter referred to as screws B) with a length of about 25 ribs of concrete, fix the GRC and the cut pieces of the sash, and cure for 7 days at 2000 humidity of 80 to 90%. After removing the mold and leaving it for another 14 days,
A pullout test was conducted by setting a pullout tester on the side of the cut piece of the sash that was not in contact with the GRC.

Unless otherwise specified, tapping screws were screwed in using an electric screwdriver, and concrete nails were screwed in or driven in using a hammer. The results are shown in the table below. *Due to buckling of the two sashes, further strength measurement is not possible (approximately 140 to 1
(Buckling at about 90°C) In this way, the mountain ladder in Book B, ``Hyure''.

It has a much higher pull-out strength than conventional fixing with nails, but in both cases it was impossible to measure the pull-out strength due to deformation of the cut pieces of the sash. . Furthermore, when this self-tapping screw was applied to an uncured molded body of glass fiber reinforced calcium silicate or asbestos slate, a pullout strength of several tens of k9 or less was obtained in all cases. In addition, in the example using screw B, even if the screw is pulled out with a screwdriver several times after the GRC hardens, there is little loss of the thread on the GRC side, and relatively high pullout strength can be maintained. Compared to the JIS tatsupin screw of screw A, the pullout strength was less reduced due to the pullout of the screw.

Claims (1)

[Scope of Claims] 1. A method for fixing GRC, in which a GRC is molded, a desired member is placed on the GRC while the GRC is uncured, and the GRC and the member are fixed using tuft pin screws. 2. Molding the GRC, placing a desired member on the GRC while the GRC is uncured, applying pressure as necessary, and molding the GRC.
2. The method of fixing a GRC according to claim 1, wherein the surface of the C is brought into close contact with the member by partially deforming the surface, and the GRC and the member are fixed with a tuft pin screw. 3. The GRC fixing method according to claim 1 or 2, wherein the GRC and the member are fixed while the GRC compressive strength is 10 kg/cm^2 or less. 4. The method for fixing a GRC according to any one of claims 1 to 3, which fixes using a tuft pin screw having a double helix with different heights. 5. The method for fixing GRC according to any one of claims 1 to 3, wherein the GRC is a GRC containing 1 to 8 wt% of glass chopped strands having a length of 10 to 5 mm.