JPH0647871B2 - Formwork - Google Patents

Description

TECHNICAL FIELD The present invention relates to a mold for placing cement mortar such as cement mortar or concrete slurry.

[Problems to be Solved by the Invention]

When mortar is cast in the mold, bubbles in the mortar collect on the surface of the mold plate, and after demolding, many patters are generated on the surface in contact with the mold plate, especially on the inclined surface. There are problems such as impairing the aesthetics of the product and lowering the durability due to the weakness of the pock.

Various measures have been proposed for this problem. For example, there is a means of providing drain holes at predetermined intervals in a form plate and attaching a porous material made of a fibrous material having air permeability and water permeability to the surface thereof. It is known that this means discharges air bubbles in the mortar to prevent generation of surface pockmarks, and dehydrates surplus water to improve surface strength. However, in this method, the efficiency of exhaust and dehydration is not always sufficiently high, and a large number of drain holes must be formed in the form plate, making it difficult to divert the form plate to another, and its operation is difficult. There was a drawback that the rate was low. Further, the porous material becomes a thick woven fabric having both a filtering function and a water permeable function, which causes a high cost (a material cost of about 1,500 to 2,000 yen / m ² ) and is difficult to use repeatedly, and it is required to reduce the cost. .

The present invention has been made in view of the above circumstances. The purpose is that there is no need to use a special form plate having a large number of drainage holes, the form cost is low, and the efficiency of exhausting air bubbles and dewatering excess water is good, and the surface of the obtained structure is It is an object of the invention to propose a form that is flat and can significantly reduce the generation of pock and improve the surface strength and durability.

[Means for Solving the Problems]

This formwork has a drainage material layer and a filtration material layer laminated in order on the inner surface of the formboard of the formwork for placing cement mortar, and the filtration material layer is substantially composed of solid particles in the cement mortars. Is a layer through which water and air can permeate without passing through, and the drainage material layer is a layer through which water and air that permeate through the filter material layer can flow in a direction parallel to the form plate, and has a large number of irregularities. Consists of sheets, the proportion of the convex area that contacts and supports the filter medium occupies 60 to 90% of the total area, and the bottom of the formwork has a drain hole, or the peripheral part of the formwork is drained. It is characterized by having holes.

The present invention will be described below with reference to the form plate of this form shown in FIG.

A drainage material layer 2 and a filtration material layer 3 are laminated in contact with the inner surface of a form plate 1 such as a plywood or a metal home. FIG. 1-1 shows a resin sheet 4 having convex portions 5 on the inner surface of the form plate 1 and the convex portions 5 on the upper surface, which are bonded together to form a drainage material layer 2 and a filtration material layer 3.
Is a mold formed by adhering to the upper surface of the convex portion 5.

The filter material layer is made of a material through which solid particles in the mortar do not substantially pass and moisture and air can pass. As such a filtering material, for example, a fiber density of 20 to 1 using a synthetic fiber multifilament system of 70 to 500 denier is used.
A plain weave of 00 pieces / 2.54 cm is suitable.

The drainage material layer 2 is a layer of a material through which air and water can flow. In the figure, a plastic sheet having a concavo-convex portion provided with a large number of convex portions 5 bulged on one surface of a thermoplastic resin sheet 4 made of polyethylene, polystyrene, polyvinyl chloride or the like is used.

In addition, as the drainage material, sheets having a large number of irregularities, for example, a sheet of a metal thin plate provided with a large number of convex portions using a steel plate, an aluminum thin plate or the like as a base material, or laminated 2
It is possible to use so-called air packing in which a large number of air bubbles are formed between the sheets, or sheets of mesh-like mesh for drainage made of synthetic resin or metal.

The drainage material is between the form plate and the filtration material, withstands the mortar casting pressure, maintains the discharge gap of moisture and air, and enables the flat casting concrete surface to be plasticized.
The filter material must be kept flat and accurately supported in place. Assuming that the form fiberboard is vertically assembled by using the synthetic fiber woven fabric as the filtering material, the area ratio of the convex portion of the drainage material which contacts the filtering material and supports the filtering material is 60% of the total area.
Must be ~ 90%. If it is less than 60%, it becomes difficult to maintain the filtering material accurately, the drainage gap is crushed, and unevenness is generated on the plastic concrete surface. On the other hand, when it is 90% or more, the volume of the drainage gap becomes small and the functions of drainage and deaeration deteriorate, which is not preferable.

Figure 2-1 shows that a rough polyethylene mesh sheet is used as the drainage layer 2, and the mesh spacing is 0.5.
~ 2mm is suitable.

FIG. 1-2 shows a state in which concrete is poured into a formwork constructed by using the die-cutting plate of FIG. 1 and placed. A mold plate 1 constituting one vertical surface of the mold has an inner surface on which a drainage material layer 2 and a filter material layer 3 are laminated in order, and a drainage hole 6 is formed on the lower end of the formwork board 1. . The concrete slurry 7 injected into the mold comes into contact with the filter material layer 3, and the air collected at the interface permeates the filter material layer 3 and enters the drainage material layer 2. At the same time, excess water in the concrete slurry 7 is pushed to the internal pressure. It permeates through the filter material layer 3 and enters the drainage material layer 2. The air and excess water are discharged from the drainage holes 6 at the lower end of the form plate.

The form plate shown in FIG. 2-2 is one in which the drainage material layer 2 is rotated to the lower end surface of the formwork to provide a drainage gap for drainage, and thus the drainage material layer is continuously used at the peripheral portion of the formwork. When the drainage gap is provided, it is not necessary to open a drainage hole in the form, which is preferable in terms of workability and economy.

In the case of a conventional formwork in which a porous material is arranged on a formwork plate having a large number of drainage holes, one layer functions to separate, transport, and discharge water and air, and therefore its function is insufficient. there were.
In the case of this form, water and air are separated by the filter material layer, which is collected in the drainage material layer and transported and discharged, so that the speed of exhaust and dehydration is significantly improved. Therefore, the concrete structure cast with this formwork has few pockmarks on the surface, and the strength is remarkably improved. Also, the drainage material layer acts as a heat insulating layer,
Effective for curing early concrete.

By selecting the surface shape of the filter material appropriately, the concrete surface can be made into a shape that matches the purpose of use.

[Example (1)] Height h = 50 cm and thickness t = 2 shown in FIGS. 3 (a), (b), and (c).
A mold having a width of 3 cm, a width of 50 cm, and an inclination of 90 °, 45 °, and 30 ° is prepared, and the drainage material layer 2 and the filtration material layer 3 (first 1-1 Type of figure)
9 and 9 were laminated, and a drain hole 6 having a diameter of 5 mm for measuring the dehydration amount was formed at the lower end thereof.

A concrete slurry having the following composition was poured into the mold, and compacted with a vibrator to accelerate exhaust and dehydration, and the amount of dehydration from the dehydration hole during this period was measured. After the concrete was hardened, deframing was performed and the area and surface hardness were examined. In addition, a comparative example experiment was conducted under the same conditions as those of the example using plywood frame plates on both sides.

Amount of patter (ratio of patter area to mold surface area) Tilt angle 30 ° (Comparative example) 8.3% (Experimental example) 0.21% Tilt angle 45 ° (Example) 0.18% Tilt angle 90 ° (Comparative example) 0.66% (Implementation) example) 0.24% surface hardness (measured by Schmidt hammer) tilt angle 30 ° (Comparative example) 293kg / cm ² (example) 372kg / cm ² the inclination angle of 45 ° (example) 382kg / cm ² the inclination angle of 90 ° (comparative example) 290 kg / cm ² (example) 401kg / cm ² ratio inclination angle 30 ° of the dewatering amount for water of dehydration weight concrete slurry (example) 2.3% 45 ° (experiment) 2.8% 90 ° (example) 3.3% [Example (2)] Height h = 50 cm and thickness t = 23c shown in FIGS. 3 (a) and 3 (c)
Prepare a formwork with m, width of 50 cm and inclination of 90 °, 30 °,
The drainage material layer 2 and the filtration material layer 3 (type shown in FIG. 2-1) are laminated on the inner surface of the mold plate (upper side in the case of an inclined surface) on one side, and the industrial double-sided tape is applied at the end of the mold. It was attached using a stapler, and drainage was carried out from the gap at the lower end of the formwork without providing a drainage hole in the formwork plate.

A concrete slurry having the same composition as in Example (1) was poured into this mold, and compacted with a vibrator to accelerate exhaust and dehydration, and the dehydration amount during this period was measured. After the concrete was hardened, it was deframed, and the pock area and surface hardness were examined. Also,
With respect to the 90 ° mold, the concrete slurry was repeatedly injected into the mold without cleaning the surface of the mold, and the number of times it could be converted was checked. As a result, it was confirmed that the mold could be converted many times.

Experimental results Amount of patter (ratio of patter area to mold surface area) Tilt angle 30 ° (Comparative example) 8.3% (Example) 0.22% Tilt angle 90 ° (Comparative example) 0.66% (Example) 0.18% (Diversion (2 0.20%, (3 times) 0.16%,
(4 times) 0.21%) surface hardness (measured by Schmidt hammer) tilt angle 30 ° (Comparative Example) 293kg / cm ² (Example) 368 kg / cm ² the inclination angle of 90 ° (Comparative Example) 290 kg / cm ² (Example ) 406 kg / cm ² [Effects of the Invention] The invention is as described above. This formwork has excellent functions of discharging excess water and degassing air bubbles when pouring concrete, the surface of the plastic concrete structure is flat, the patter is drastically reduced, and strength and durability are at the same time. improves. Further, since it is not necessary to form a large number of drain holes in the form, it can be diverted, and the drainage material and the filtration material can be used in 200-
Since the cost is as low as 300 yen / m ^2, it is possible to significantly reduce the cost of the formwork as compared with the conventional formwork.

[Brief description of drawings]

1-1 and 1-2 are respectively a perspective view showing a partial cross section of a form plate of this form and a cross-sectional view of a state in which concrete slurry is poured into contact with the form plate, FIG. 2-1. Second-
FIG. 2 shows another example of the form plate, and is a perspective view of the form plate and a cross-sectional view of a state where concrete is poured. FIGS. 3 (a), (b), and (c) are cross-sectional views of the molds having the inclination angles of 90 °, 45 °, and 30 ° according to the embodiment, respectively. DESCRIPTION OF SYMBOLS 1 ... Form plate, 2 ... Drainage material layer, 3 ... Filtration material layer, 4 ... Resin sheet, 5 ... Convex part, 6 ... Drainage hole, 7 ... Concrete slurry.

Front page continuation (72) Inventor Shojiro Nakagami 3-12-10 Hakataekimae, Hakata-ku, Fukuoka City, Fukuoka Prefecture Kashima Construction Co., Ltd. Kyushu Branch (56) Reference JP-A-60-181462 (JP, A) 55-126345 (JP, U)

Claims (2)

[Claims] 1. A drainage material layer and a filter material layer are sequentially laminated on the inner surface of a form plate of a mold for placing cement mortar, and solid particles in the cement mortar are substantially provided in the filter material layer. Is a layer through which water and air can permeate without passing through, and the drainage material layer is a layer through which water and air that permeate through the filter material layer can flow in a direction parallel to the form plate, and has a large number of irregularities. A form made of sheets, the proportion of the area of the convex portion contacting and supporting the filter medium occupies 60 to 90% of the total area, and a drain hole is formed at the lower end of the form. 2. A drainage material layer and a filter material layer are sequentially laminated on the inner surface of a form plate of a mold for placing cement mortar, and the filter material layer is substantially composed of solid particles in the cement mortar. Is a layer through which water and air can pass, and the drainage material layer is a layer through which the water and air that have passed through the filter material layer can flow in a direction parallel to the form plate, and which has a large number of irregularities. A mold which is made of a similar material and has a proportion of the area of the convex portion which is in contact with and supported by the filter medium and accounts for 60 to 90% of the total area, and a drainage gap is provided in the peripheral portion of the mold.