JPH0655367B2 - Concrete board for formwork and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a concrete board for a formwork having an aggregate layer formed on the surface thereof and a manufacturing method.

<Prior Art> As is well known, various concrete boards have been proposed, and when this concrete board is joined to another concrete skeleton, that is, it is used as a formwork for forming a concrete skeleton into a desired shape. When used as an embedded formwork or abandoned formwork that is not removed even after the hardened concrete for structure is hardened, a connecting tool, a reinforcing bar and the like are extended from the concrete board.

On the other hand, in general, concrete may have voids when it is cured depending on the construction conditions such as the grain size of the aggregate and the squeezing condition. Since the voids prevent the formation of solid concrete and reduce the durability and strength, and the airtightness and watertightness, the above voids must be avoided. On the other hand, on the other hand, there is one in which a void is formed between the aggregates and water permeability is imparted to the concrete by utilizing this void.

<Problems to be Solved by the Invention> When joining a concrete board to another frame, a connector was used, or a reinforcing bar or the like extended from the concrete board was used to join the frame to the frame. In that case, the construction is troublesome, and the reinforcing bars and the like extending from the concrete board are an obstacle to handling and carrying.

Further, breathing occurs when concrete is poured into the surface, breathing water floats on the surface, and the density near the surface layer of the concrete decreases, so that the shrinkage on the surface layer side becomes large during drying and warpage is likely to occur. In particular, in the case of a plate having a thin cross section, the effect of breathing is remarkable.

<Means for Solving the Problems> The present invention has been proposed in view of the above, and on the surface of an uncured concrete layer cast to a required thickness, a binder is prepared on the surface while being adjusted to a required particle size. By continuing to attach the aggregate, the aggregate layer having a continuous void between the aggregate is integrally formed, the concrete layer and the aggregate layer are cured, and the aggregate layer is exposed. A concrete board for a mold and a method for producing the same, in which the aggregate layer is used as a joint surface of a concrete skeleton.

In addition, on the surface of the uncured concrete layer that is cast in a thin wall, the aggregate with the required grain size adjusted according to the cast state of the concrete and the binder adhered to the surface is placed between the aggregates. While adjusting the amount of aggregate to absorb breathing water in the formed continuous voids, it is spliced and integrated,
A concrete board for a formwork, in which shrinkage is suppressed by curing the concrete layer and the aggregate layer, and a method for producing the concrete board.

Further, it is a concrete board for formwork in which a connecting jig having a slip-out preventing means is provided at a predetermined position of an uncured concrete layer, and the connecting jig is integrated with at least the concrete layer, and a manufacturing method thereof.

<Operation> Aggregates are interconnected by a connecting material to form an aggregate layer having continuous voids between the aggregates, and a part of the aggregate is embedded in the concrete layer to form a concrete layer. Become one. Then, the surface of the aggregate layer becomes extremely rough, and the post-cast concrete that is poured to form the concrete skeleton into the continuous voids of the aggregate layer can flow in. Therefore, the post-cast concrete and the aggregate layer are firmly bonded.

<Examples> Hereinafter, the present invention will be described with reference to Examples of the drawings.

An outline of the concrete board 1 for a formwork according to the present invention will be described. A first step of forming a concrete layer 2 by pouring concrete and an aggregate by staking the aggregate while the concrete layer 2 is in an uncured state. Second step of forming the layer 3 and third step of curing the concrete layer 2 and the aggregate layer 3
It is manufactured consistently in the manufacturing factory through the process.

In the first step, for example, a concrete frame or a special concrete mixed with fine aggregate or sand is cast into a mold for production (not shown) to have a required thickness, and the concrete layer 2
Make up.

In the second step, while the concrete layer 2 in the first step is in an uncured state, cement paste as a binder, on the surface of the aggregate prepared to have a required particle size (for example, crushed stone No. 6),
A special pace and the like are attached, and this aggregate is spliced to the concrete layer 2 described above. In the second step, since the concrete layer 2 is in an uncured state, a part of the aggregate is embedded in the concrete layer 2, and the aggregates are bonded to each other by the binder to form the aggregate layer 3, Voids are formed between the aggregates. Then, the voids communicate with each other to form a continuous void.
Incidentally, the non-rough surface portion 2'where the aggregate layer 3 is not provided may be left around the concrete board 1 or a required portion.

In the third step, the concrete layer 2 and the aggregate layer 3 are dehydrated by vibration or centrifugal force, and if necessary heated and cured. By this curing, the concrete layer 2 and the aggregate layer 3 are hardened and firmly bonded.

The concrete board 1 for a formwork of the present invention, which is produced in a factory through the above-described steps, has the aggregate exposed to the surface, the surface being extremely rough, and having continuous voids.

Next, a case of constructing a concrete structure using the concrete board 1 for formwork as described above will be described.
For example, as shown in FIG. 2, in the case where the concrete structure 4 is plate-shaped, the bottoms in which the molds 5 and 5 made of veneer plywood or the like, which are removed after the driven-in concrete has been hardened, are arranged to face each other. In addition, the concrete board 1 according to the present invention so that the aggregate layer 3 is on the upper side (the inner side as the formwork).
Is laid, and then structural concrete 6 is placed and cured. In addition, as shown in FIG. 3, when the concrete structure 4 is a long rod-shaped member such as a beam, the concrete board 1 is assembled in a generally square groove shape with the aggregate layer 3 inside. The outer surface is supported and the structural concrete 6 is placed inside for curing. In addition, reinforcing bars may be provided inside the structural concrete 6 or prestressed concrete may be used.

In the concrete structure 4 as described above, there is an aggregate layer 3 at the joint between the formwork concrete board 1 and the structural concrete 6, and the aggregate layer 3 has an extremely rough surface and continuous voids. Are innumerable. Therefore,
The joint surface becomes extremely rough and the post-cast structural concrete 6 flows into the deep part of the continuous voids and hardens, so that the formability concrete board 1 and the structural concrete 6 have excellent jointability. Further, according to the concrete board for formwork 1 as described above, the concrete board for formwork 1 becomes a so-called discarded formwork that does not need to be removed, so that the construction is significantly facilitated. Further, since it is possible to suppress the consumption of wood resources such as plywood, it is possible to contribute to the protection of the natural environment.

On the other hand, when the concrete board 1 is made thin, warpage and shrinkage are likely to occur. That is, breathing occurs during curing of concrete, and unnecessary moisture floats on the surface as breathing water. Due to this breathing, the density near the surface layer of the concrete decreases, and the shrinkage on the surface side increases during drying, causing warpage. As the concrete board 1 becomes thinner, this shrinkage is more seriously affected by breathing.

When manufacturing concrete products, even in the case of the same standard products, the water-cement ratio, fine aggregate ratio, aggregate-cement ratio, drying time, etc. can be changed in the working environment in the summer when the temperature is high and humidity and the winter when the temperature is low. Have changed accordingly. Then, the changed concrete has different breathing occurrence states.

It is generally known that so-called porous concrete having continuous voids has less shrinkage during drying than ordinary concrete or lightweight concrete. Further, the difference in the grain size of the aggregate affects the shrinkage strain, and the shrinkage strain becomes smaller as the maximum size of the aggregate becomes larger. On the other hand, the shrinkage strain decreases as the aggregate-cement ratio increases.

Therefore, the present invention, when producing a thin concrete board 1 for formwork that is likely to warp or shrinkage, after the concrete is cast into a thin wall, the concrete is in the uncured state, and the concrete is in the cast state, That is, water-cement ratio, fine aggregate ratio, aggregate-cement ratio, corresponding to the floating state of breathing water caused by changes in drying time, the aggregate with the required particle size is prepared and the binder is attached to the surface. The aggregate amount is adjusted to absorb the breathing water in continuous voids formed between the aggregates, and the aggregates are spliced and integrated. Therefore, the breathing water can be absorbed in the continuous voids formed in the aggregate layer 3 and the adverse effect of the breathing water can be removed, and the warpage and shrinkage of the concrete due to the interference between the aggregates whose content has been adjusted. Curing can be performed while suppressing the above.

According to the present invention as described above, despite being thin,
It is possible to provide a high-quality concrete board 1 without warpage or shrinkage. Also, the concrete board 1
Has an extremely rough surface and has an aggregate layer 3 having continuous voids, and therefore has very good bondability with post-cast concrete forming a concrete structure.

Such a thin formwork concrete board 1 can be used as an embedded formwork of a concrete structure or the like.

Further, a connecting jig may be provided on the concrete board 1 for formwork of the present invention. That is, the concrete layer 2 is formed by pouring concrete to a required thickness, and while the concrete layer 2 is in an uncured state, the concrete layer 2 is prepared to have a required particle size and bonded to the surface. The aggregate to which the aggregate has been adhered is spliced to integrally form the aggregate layer 3 having continuous voids between the aggregates. In addition, a disconnection preventing means 7, for example, a connecting jig 9 having a flange portion 8 is provided at a predetermined position of the uncured concrete layer 2.
As shown in FIG. 6, this connecting jig 9 is provided with flange portions 8 at both ends of a tubular portion 10 and threaded portions 11 formed on the inner surface of the tubular portion 10.
It is located inside and has screw holes communicating from the concrete layer 2 to the aggregate layer 3. Accordingly, when the concrete layer 2 and the aggregate layer 3 are cured, the flange portion 8 of the connecting jig 9 is firmly fixed in the concrete layer 2, and the flange portions 8 at both ends substantially fix the concrete board 1 for formwork. It does not fall off even with external force in one or two directions acting at a right angle. Moreover, this connecting jig 9
Since it does not project from the concrete board 1 for formwork, it does not interfere with transportation or storage and is easy to handle. In the illustrated embodiment, the connecting jig 9 is embedded in the peripheral non-rough surface portion 2'where the aggregate layer 3 is not provided.
The connecting jig 9 may be embedded from the concrete layer 2 to the aggregate layer 3. In this case, since the connecting jig 9 also acts as a reinforcing material that assists the connection between the concrete layer 2 and the aggregate layer 3, a stronger connection can be obtained.

FIG. 7 shows another embodiment of the connecting jig 9, in which the slip-out preventing means 7 is located in the concrete layer 2 and screw holes are opened in the aggregate layer 3.

FIGS. 8 to 9 show a concrete board 1 for formwork provided with another connecting jig 9, and a screw portion 11 is provided inside.
The so-called P-con 12 made of a truncated cone-shaped synthetic resin having the above is used as the connecting jig 9.

In the concrete board 1 for a mold, concrete is cast to a required thickness to form a concrete layer 2, and while the concrete layer 2 is in an uncured state, a required grain size is obtained on the surface of the concrete layer 2. The aggregate layer 3 having the continuous voids between the aggregates is integrally formed by continuously joining the aggregates to the surface of which the binding material is adhered. P-con 12 having screw part 11
While the large diameter portion 12a is projected to the aggregate layer 3 side,
A taper hole 13 in which the small-diameter portion 12b is provided so as to be depressed in the concrete layer 2 or the P-con 12 can be fitted.
It is configured by locating a plug member for forming the. In addition, in this concrete board 1 for formwork,
The second inclined surface 12 ′ serves as the slip-out preventing means 7.

When the concrete board 1 for formwork as described above is used, as shown in FIG. 8, the concrete tie 14 is supported by screwing the foam tie 14 onto the P-con 12 fitted in the tapered hole 13. Work. Further, as shown in FIG. 9, while engaging the locking piece 16a of the special washer 16 that is bent in a substantially Z-shape with the flange portion 15a of the H steel 15,
The bolt 18 inserted into the through hole 17 formed in the fastening piece 16b of the washer 16 is screwed to the P-con 12 to support the work. Then, concrete is appropriately poured and after curing, the foam tie 14, the bolt 18, the H steel 15 and the like are removed, and the front end portion of the tapered hole 13 is filled with mortar or the like.

According to the concrete board for formwork 1 having the connecting jig 9 as described above, not only the bondability between the rough surface of the aggregate layer 3 and the post-cast concrete due to the continuous voids is improved, but also the joining is performed by the connecting jig 9. The strength can be improved. Further, the connecting jig 9 facilitates the positioning, and also facilitates the support work until the post-cast concrete is cured.

<Effects of the Invention> According to the present invention, the aggregate layer and the concrete layer are integrated, and the aggregate layer has a very rough surface and has continuous voids. If it is used as a joint surface with the post-cast concrete, the post-cast concrete flows into the continuous voids and is hardened, and in addition to the extremely rough joint surface, the bondability is very good.

In addition, since the aggregate is spliced into the uncured concrete layer to absorb the breathing water of the uncured concrete and interfere with each other to prevent warpage and shrinkage of the concrete layer, the concrete layer can be made thin. Even if there is, warpage and shrinkage are extremely small.

Further, it is possible to provide a connecting jig, and the connecting jig can further improve the bonding strength. Moreover, the connection jig facilitates positioning and support, and the workability is significantly improved. In addition, the connecting jig does not interfere with storage and transportation, and is easy to handle.

[Brief description of drawings]

Drawing shows an embodiment of the present invention, Fig. 1 is a perspective sectional view of a concrete board for formwork, Fig. 2 is a perspective sectional view of a concrete structure, and Fig. 3 is a perspective sectional view of another concrete structure, 4 is a perspective sectional view of a thin concrete board, FIG. 5 is a perspective view of a concrete board for a formwork provided with a connecting jig, FIG. 6 is a sectional view taken along line VI-VI of FIG. 5, and FIG. 9 to 9 are sectional views of a concrete board for formwork provided with another connecting jig. 1 ... Concrete board for formwork, 2 ... Concrete layer,
3 ... Aggregate layer, 7 ... Removal prevention means, 9 ... Connection jig.

Claims (6)

[Claims] 1. A concrete board for a formwork, which is used in a formwork for forming a concrete structure and is not removed even after the post-cast concrete is hardened, which concrete is cast in a required thickness in an uncured state. On the surface of the layer, the aggregate having the required grain size adjusted and the binder attached to the surface is spliced to integrally form an aggregate layer having continuous voids between the aggregates, and the concrete layer and the bone A concrete board for formwork, characterized by curing the aggregate layer to expose the aggregate layer, and using the aggregate layer as a joint surface of a concrete skeleton. 2. A method for producing a concrete board for a formwork, which is used in a formwork for forming a concrete structure and is not removed even after the post-cast concrete is hardened, which is an uncured cast in a required thickness. On the surface of the concrete layer in the state, the aggregate having the required grain size and having the binder adhered to the surface is spliced to integrally form an aggregate layer having continuous voids between the aggregates, A method for manufacturing a concrete board for a formwork, which comprises curing a layer and an aggregate layer. 3. A concrete board for a formwork, which is used for a formwork for forming a concrete structure and is not removed even after the post-cast concrete is hardened, the surface of an uncured concrete layer cast in a thin wall. To
The amount of aggregate is adjusted so as to absorb the breathing water in the continuous voids formed between the aggregates, which is adjusted to the required grain size according to the concrete pouring condition and the surface of which the binder is attached. A concrete board for a formwork, characterized in that the concrete layer and the aggregate layer are cured so as to suppress shrinkage. 4. A method for producing a concrete board for a formwork, which is used for a formwork for forming a concrete structure and is not removed even after the post-cast concrete is hardened, wherein the concrete is uncured in a thin wall. On the surface of the layer,
The amount of aggregate is adjusted so as to absorb the breathing water in the continuous voids formed between the aggregates, which is adjusted to the required grain size according to the concrete pouring condition and the surface of which the binder is attached. A method for producing a concrete board for a formwork, which comprises piecing together while adjusting the above, and curing the concrete layer and the aggregate layer. 5. The concrete board for formwork according to claim 1, wherein a connecting jig having a slip-out preventing means is provided at a predetermined position of the uncured concrete layer, and the connecting jig is integrated with at least the concrete layer. 6. The method for producing a concrete board for a formwork according to claim 2, wherein a connecting jig having a removal preventing means is provided at a predetermined position of the uncured concrete layer to cure the concrete layer and the aggregate layer.