JP3869667B2 - Concrete formwork holding device end stop and concrete structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a concrete formwork holding device for fastening and holding a formwork when placing concrete, and more particularly to an end stopper used in the holding device and a concrete structure having this end stop. is there.
[0002]
[Prior art]
As a formwork holding device used at the time of manufacturing a concrete structure, it has a separator (connection rod) and an end stopper (plug) fixed to one end or both ends of the separator, and the external direction of the formwork The mold frame is held by the mold clamp body to be inserted and the end stopper, and when the concrete is placed, the separator and the end stopper are embedded in the concrete structure.
Various types of end stops of such concrete formwork holding devices are known.
For example, as shown in FIG. 8, in Japanese Patent Laid-Open No. 8-135187, an end member 1 is constituted by an exterior member 1a made of ceramics and a metal nut 1b fitted inside the exterior member 1a. The tip of the separator 2 is screwed to 1b. 3 is a formwork, 4 is a bolt as a formwork fastening body.
[0003]
FIG. 9 shows the structure of the end stop 1 by combining a plurality of divided end stops made of ceramics in order to adjust the cover thickness. (A) of the figure is a combination of a plurality of members having the same diameter, and a metal nut 1b is fitted to a split end stopper disposed on the innermost side, and a separator 2 is screwed onto the metal nut 1b. The bolt 4 is screwed into the metal nut 1b from the outside of the mold 3. FIG. 9B shows a structure in which the end stoppers 1 having different diameters are combined.
[0004]
FIG. 10 shows an exterior member 1a constituting the end stop 1, which is formed by mixing a resin with mortar, and a screw cylinder portion 1b is inserted therein. The separator 2 is screwed to one side of the threaded cylinder portion 1b, and the mold fastening body 4 is screwed to the other side through the mold 3 and the concrete 6 is placed. After the concrete is cast, the mold 3 and the mold clamping body 4 are removed, but the outer hole of the screw cylinder portion 1b after the removal is filled with mortar or screwed with a screw cap to close the hole. .
[0005]
[Problems to be solved by the invention]
In each of the above-mentioned conventional ones, even if a part of the end stopper embedded in the concrete structure is formed of ceramics or mortar, the end stopper is screwed in order to screw the separator or the mold fastening body. Since the screw disposed inside is a metal internal screw, even if this metal member is covered with ceramic or mortar mineral, this inorganic part will not deteriorate, but moisture will penetrate into the metal part inside it. Then, rust corrosion occurs and the corrosion spreads to the separator made of metal.
In order to prevent moisture from entering, even if the concrete surface is covered with resin or a cap after removing the formwork, it will deteriorate due to secular change due to long-term use, etc. Corrodes.
When corrosion starts on the end-stop body portion, deterioration such as cracks on the surface of the concrete structure starts, which impairs the durability of the concrete structure.
[0006]
Accordingly, an object of the present invention is to provide an end stop and a concrete structure that do not cause corrosion.
[0007]
[Means for Solving the Problems]
1st of this invention consists of the ceramic sintered compact with which at least one end of a separator is mounted | worn, and the end stop body in which the uneven | corrugated | grooved part was formed in the outer surface part, and the internal thread part formed in the inside of this end stop body In a concrete formwork holding device provided with a formwork tightening body for engaging with a formwork through
The end body is mainly composed of aluminum oxide, zirconia, silicon carbide, or silicon nitride having 90 to 98 W%, and a secondary component as a sintering aid is added to the main component in an amount of 2 to 10 W%, The mixture is crushed and granulated, then molded, and fired at 1500 to 1700 ° C. for 1.5 to 3.00 hours .
[0008]
According to a second aspect of the present invention, concrete is placed in a mold of a concrete mold holding device formed by engaging the end stop and a mold clamp, and the subsequent mold and mold clamp It is characterized by having been removed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of the present invention. Reference numeral 10 denotes an end stopper in the present invention. This end stopper 10 is made of ceramics, and a female thread portion 11 is formed at the center of the inner axial direction when the ceramic is sintered. Further, after the concrete 6 is placed, the end stop 10 has an outer surface in contact with the concrete, for example, a spherical shape in which a central portion in the axial direction bulges, and a part of the end body 10 as necessary. The uneven part which has the notch part 12 for strengthening a rotation stop or tensile force is formed. The tip of the separator 2 is screwed to one end of the female screw portion 11. At this time, the chamfered portion 13 having a slightly larger diameter than the female screw portion 11 so that the tip of the separator 2 can be easily fitted into the female screw. Is provided. The mold fastening body 4 is screwed to the end separator 10 on the side opposite to the separator so as to hold the mold 3.
[0016]
FIG. 2 is a block diagram of the concrete mold holding device. End stoppers 10 configured as shown in FIG. 1 are attached to both ends of the separator 2, respectively, together with the mold clamping bodies 4. 3 is held and concrete is placed between the two molds to form a concrete structure.
In addition, 7 is a crosspiece, 8 is a pipe, 9 is a contact body, these are attached via the nut of the formwork clamping body 4 on the outer side (anti-concrete placement side) of the formwork 3, Support is strengthened. After the concrete is cast and cured for a certain period of time, the nuts of the mold fastening body 4 are removed, the contact body 9, the pipe 8, and the pier 7 are removed, and then the screw between the fastening body 4 and the end stop body 10 is removed. The mold 3 can be dismantled from the concrete structure by releasing the combination.
[0017]
FIG. 3 shows a seal 14 made of a rubber ring or the like interposed between the end stop 10 and the mold 3 when the concrete mold holding apparatus is assembled. By comprising in this way, the adhesiveness of the formwork 3 and the end-stop body 10 is improved, the penetration | invasion of the concrete into the end-stop body 10 at the time of concrete placement is prevented, and damage to the end-stop body by an impact Is to prevent.
After the concrete is placed, the seal 14 is removed as shown in FIG.
The seal 14 is affixed with a one-component adhesive, but as the adhesive, for example, a cyanoacrylate-based instantaneous adhesive is used, and this instantaneous adhesive can quickly perform the bonding operation, Further, there is an advantage that peeling can be easily performed at the time of removal.
[0018]
FIG. 4 shows an example in which the filler 15 is packed into the hole of the female screw portion 11 generated after the mold is disassembled.
In the hole of the female thread portion 11 after the mold form is disassembled, an eyebolt or the like may be screwed and used for performing mortar application work through a lifeline for worker safety, or after manufacturing a concrete structure. When the structure is not used immediately, a filler 15 such as a cap or a mortar is inserted into the outer opening of the female screw portion 11 to prevent intrusion of dust or moisture.
When the filling 15 is a cap, it is preferable to display on the surface thereof whether it is a metric screw or a wit screw, and display the size of the screw, for example, M12 or W12. This is because both the metric screw and the wit screw are used as the female screw portion 11 of the end stopper 10 to be used, so that the discrimination is made easier at a later date.
[0019]
FIG. 5 shows a case where the cylindrical portion of the end stopper 10 is changed in accordance with the fogging. FIG. 5A shows the auxiliary cylinder 10a formed in a cylindrical shape with ceramics by an adhesive. The cover is enlarged by bonding to the tube part. As the adhesive used here, an epoxy resin that cures at room temperature is used, for example, an epoxy resin two-part adhesive, and the main component is an epoxy resin (bisphenol A type epoxy resin intermediate) as a main component. It consists of a filler and a dye, and the curing agent consists of polythiol as a main component and a filler. The two liquids of the main agent and the curing agent are mixed at 50:50, and after application, both are joined and spontaneously cured and bonded in a stationary state. (B) In the figure, the cylindrical portion 10b itself of the end stop 10 is integrally formed long to ensure the cover. At that time, a step 12a different from the notch 12 is provided to provide a strong detent. It can be.
[0020]
In FIG. 6, a partition wall 16 is provided in a hollow portion (female screw portion) of the end stopper 10, and the partition wall 16 is formed integrally with the end stopper and ceramics or by a separate member. By configuring in this way, even if there is water immersion, moisture intrusion to the separator 2 side can be prevented by the partition wall 16, and corrosion of the metal separator 2 can be prevented.
[0021]
FIG. 7 shows an example for strengthening the detent or pulling force.
(A) The figure shows an uneven part 17 provided on the outer peripheral part of the end stop 10.
(B) In the figure, a semicircular uneven portion 17 and a pressure receiving portion 18 are provided. The pressure receiving portion 18 is bonded to the end stopper 10 with an adhesive in the same manner as in FIG.
(C) The concavo-convex portion 17 in the figure is provided in an egg shape (circular weight shape), and one or more of the concavo-convex portions 17 in the diagrams (b) and (c) are provided in the outer peripheral portion of the end stopper. It is done.
Moreover, the end stop 10 of the (d) figure is formed in the polygon.
[0022]
The end stop made of ceramics formed as described above is manufactured as follows.
[0023]
First, in the weighing step, any one of aluminum oxide, zirconia, silicon carbide and silicon nitride is used as the main component of the ceramic sintered body in the present invention. Here, for example, aluminum oxide is used as the main component. In this case, a predetermined amount (in the range of 90 to 98 W%) of Al ₂ O ₃ powder having an average particle diameter of 1 μm or less and a purity of 99.9% or more is weighed, and a subsidiary component as a sintering aid is added. When the amount of aluminum oxide as a main component is 90 W% or less, the strength of the end stop functioning as a connection joint is insufficient, and in particular, the thread of the thread portion is damaged. On the other hand, if it is 98 W% or more, it is necessary to increase the sintering temperature, which is not economically preferable. Therefore, the range of 90 to 98 W% is appropriate for the amount of Al ₂ O ₃ as the main component. MgO, SiO ₂ , and CaO are preferable as the sintering aid as an auxiliary component, and ₂ to 10 W% is added by mixing one or more of them. This subcomponent serves to lower the firing temperature.
[0024]
The weighed raw materials are sent to the mixing and crushing step. In this mixing and crushing step, pure water is added to the starting raw material consisting of the main component and subcomponents weighed in the weighing step, and the mixed crushing is performed for about 10 hours by a ball mill. And sent to the granulation process.
[0025]
In the granulation step, an organic binder such as polyvinyl alcohol and, for example, a polycarboxylic acid ammonium salt as a dispersant are added to the raw material slurry obtained by mixing and grinding, and dried at a temperature of about 150 ° C. with a spray dryer, Spray granulate. As the granulated granule, when its particle size is 30 μm or less, the fluidity is deteriorated, and it becomes difficult to fill the mold and a cavity is generated. On the other hand, when the particle size is 200 μm or more, the strength and toughness as an end stop are lowered, and it becomes difficult to obtain a desired value. Therefore, it is preferable that the material is distributed in a range of about 30 to 200 μm, and that in this distribution range occupies 80% or more.
[0026]
The granules obtained by the granulation step are filled in a desired frame mold as an end stop in the molding step, and are molded by applying pressure with an isostatic hydrostatic molding machine. The molding pressure is about 3 to 10 MPa, preferably 5 MPa. If the pressure is in the range of 3 to 10 MPa or less, chipping or cracking occurs due to insufficient molding pressure, and if it is more than that, it takes too much time until the pressure is released, and the productivity is lowered. The molded product molded in the molding process in which mold cracking is likely to occur is fired for 1.5 to 3.00 hours at a firing holding temperature of 1500 to 1700 ° C., for example, by a gas furnace in the firing process. After firing, the alumina ceramic end body is manufactured by cooling from the firing holding temperature to around 400 ° C. at a temperature drop rate of 50 to 200 ° C./hour.
[0027]
In addition, when an alumina sintered body is used as the main component of the ceramic, the raw material has an advantage that it is less expensive than zirconia or the like, but the toughness is slightly inferior. Therefore, when a material having higher fracture strength is required, a fibrous material may be added to the raw material and sintered. At that time, a fiber addition step is provided next to the above-described mixing and pulverizing step, and the mixed and pulverized powder has long fibers and short fiber whiskers made of, for example, carbon silicon at a volume ratio of about 0.01 to 5.0. What is necessary is just to send to the granulation process, after adding in the range.
[0028]
【The invention's effect】
As described above, according to the present invention, the end stop of the concrete structure is made of ceramics, and the end screw is integrally formed of ceramics up to the internal thread portion. Unlike the case where the female screw portion is made of metal, corrosion does not occur.
In addition, even if an end stop that does not cause corrosion is embedded in concrete, there is no problem of starting corrosion from the end stop, so there is no deterioration phenomenon such as cracking on the surface of the concrete structure. Since the durability of the concrete structure is not impaired, a concrete structure having high durability over a long period of time can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an end stopper showing an embodiment of the present invention.
FIG. 2 is a configuration diagram of a concrete formwork holding device using the end stopper of the present invention.
FIGS. 3A and 3B show another embodiment of the present invention, in which FIG. 3A is a diagram showing a state where a seal is attached, and FIG. 3B is a diagram showing a state after the seal is removed;
FIG. 4 is a configuration diagram of an end stopper showing another embodiment of the present invention.
FIGS. 5A and 5B show another embodiment of the present invention, in which FIG. 5A is an attached state diagram of an auxiliary cylinder, and FIG.
FIG. 6 is a configuration diagram of an end stopper showing another embodiment of the present invention.
FIGS. 7A and 7B show another embodiment of the present invention, in which FIGS. 7A to 7C are respectively modified views of an end-stop body outer shape uneven portion, and FIG. 7D is a polygonal state diagram of the end-stop body.
FIG. 8 is a configuration diagram showing a conventional end stopper.
FIGS. 9A and 9B show another conventional end stopper, in which FIG. 9A is a configuration diagram of an end stopper including a plurality of same-diameter cylindrical bodies, and FIG. 9B is an end stopper having cylindrical bodies of different diameters. FIG.
FIG. 10 is a configuration diagram showing another conventional end stopper.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,10 ... End stop body 2 ... Separator 3 ... Formwork 4 ... Formwork clamping body 6 ... Concrete 7 ... Pier 8 ... Pipe 9 ... Contact body 14 ... Seal 15 ... Filler 16 ... Septum 17 ... Concave and convex part 18 ... Pressure receiver

Claims (2)

An end stop body made of a ceramic sintered body mounted on at least one end of the separator and having an uneven portion formed on the outer surface thereof, and a mold frame is connected via a female screw portion formed inside the end stop body. In a concrete formwork holding device provided with a formwork fastening body for joining,
The end body is mainly composed of aluminum oxide, zirconia, silicon carbide, or silicon nitride having 90 to 98 W%, and a secondary component as a sintering aid is added to the main component in an amount of 2 to 10 W%, An end body of a concrete formwork holding apparatus, which is formed by mixing, crushing, granulating, and molding and firing at 1500 to 1700 ° C. for 1.5 to 3.00 hours . The concrete was placed in the mold of a concrete mold holding device formed by engaging the end stop and the mold clamping body, and the subsequent mold and the mold clamping body were removed. The concrete structure according to claim 1 .

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