JPH03219911A - Manufacture of hollow prestressed concrete panel maid of second kind lightweight concrete and formed item thereof - Google Patents

Abstract

PURPOSE:To ensure the bond between prestressing steel and concrete, prevent the sinking of hollow part and deflection at both side parts from developing and obtain a formed item having desired shape and strength by a method wherein ready-mixed concrete is pressingly placed to the extent as to conceal the top surfaces of core bars and successively network matter made of inflexible material is laid on the top surface of the placed ready-mixed concrete and, further, ready-mixed concrete same as that as mentioned above is placed on the network matter and finally the resultant surface is pressurized. CONSTITUTION:Prestressing steels P are disposed in tension to a form bed 11 by fixing its both ends to the bad. Network matter N is set to a network matter feeding device 21 so as to pass its tip on core bars 18 in order to fix to the form bed 11. Under the condition that ready-mixed concrete C is fed to feed hoppers, a movable machine frame 15 is advanced slowly. The ready-mixed concrete C in the first hopper is successively fed on the form bed 11 and, in combination with the movement of the movable machine frame 15, fed between both side forms 16 and among the core bars 18 so to reach the top surfaces of the core bars 18. Successively, the network matter N is fed on the fed ready-mixed concrete C. Further, to the upside of the network matter N, ready-mixed concrete C is fed from the second feed hopper 20. Furthermore, by passing press rollers 23 and press member 24 on the concrete just mentioned above, the top surface of the resultant concrete becomes smooth surface.

Description

Detailed Description of the Invention A1 Objective of the Invention (Field of Industrial Application) This invention relates to a prestressed concrete board for construction and construction, and in particular to a method for manufacturing a hollow prestressed concrete board and a molded product thereof. Regarding.

(Prior Art) As a conventional technique of this type, Japanese Patent Publication No. 52-31248 using ordinary concrete is known.

This method and the apparatus using this method generally include a long formwork vent with a substantially flat top surface and a movable machine frame that runs astride this, and this movable machine frame is attached in the longitudinal direction of the formwork head. A device with a base attached to the movable machine frame and several core rods extending horizontally to the rear is used to pour ready-mixed concrete between the vertical formwork on both sides. Before installation, a prestressed steel material is stretched on the formwork bed with a predetermined tension applied in the longitudinal direction of the formwork bed between the core rods and at predetermined positions on both sides, and near the base of the core rods. Mixed ready-mixed concrete is poured into the mold, pressure is applied from above at the part where the core is, and while the movable machine frame is running, a perforated ready-mixed concrete plate is formed on the form bed. After curing the concrete plate until it develops a predetermined strength,
A hollow prestressed concrete plate is manufactured by releasing the bond between the ends of the Cp material and the formwork bed.

However, when attempting to manufacture this type of hollow prestressed concrete plate using Type 2 lightweight concrete, since Type 2 lightweight concrete lacks fine aggregate content,
In order to have appropriate plasticity, the water-cement ratio in concrete must be increased, and such concrete has a reduced strength.

On the other hand, if the water-cement ratio is decreased, 11
Many voids of 1II+ or more are generated, resulting in a decrease in the strength of the concrete and a weakening of the bond with the prestressing steel.

In addition, increasing the fluidity of fresh concrete can solve the above-mentioned problem of bonding strength with the prestressing steel. Until the concrete hardens, the concrete in the cavity may cave in, or both edges of the forming plate may sag, making forming impossible.

(Problems to be Solved by the Invention) Therefore, the present invention ensures the bonding between the prestressing steel material and concrete, prevents the cavity from collapsing and sagging on both sides, and achieves the desired shape and strength. The purpose is to provide the market with a manufacturing method and molded products obtained by the manufacturing method.

Structure of the Invention (Means for Solving the Problems) In order to achieve the above-mentioned problems, this invention has a long form bed with a flat top surface and a movable frame that runs astride the form bed. , this movable machine frame has vertical side formworks extending in the longitudinal direction of the formwork bed, and between these both side formworks, a base is attached to the movable machine frame, and several middle pieces extending horizontally to the rear are installed. Using a device equipped with a child rod, before placing ready-mixed concrete, prestressing steel is applied to the formwork by applying a predetermined tension in the longitudinal direction of the form bed at predetermined positions between the core rods and on both sides. The concrete is placed on the frame bed, mixed concrete is placed near the base of the core rod, pressure is applied from above at a certain part of the core, and while the traveling machine frame is traveling, it is placed on the form bed. A perforated fresh concrete plate is formed, and after this fresh concrete plate is cured until it develops a predetermined strength, the connection with the formwork bed at both ends of the PC steel material is released to produce a hollow prestressed concrete plate. In the method, a) the composition of the ready-mixed concrete is Type 2 lightweight concrete using structural lightweight concrete aggregate specified in JISA5002, using artificial lightweight aggregate as the coarse aggregate, and fine-grained aggregate. An artificial light-weight fine aggregate and a normal fine aggregate and/or calcareous fine powder in an absolute volume ratio of 5 to 30% to the artificial light-weight aggregate were used, and the water-cement ratio was 32.
45% and add an AE agent to make the slump value 1.5.
Using ready-mixed concrete with a thickness of 5 an to 5 an, first pour the ready-mixed concrete and pressurize it to the extent that it covers the top surface of each core rod, and then pour the concrete onto the top surface with a mesh size of 60 mm x 60 m.
M to 100 na x 100 I of relatively inflexible material are sequentially laid on the surface of the poured concrete in the part where the core rod is located, and furthermore, fresh concrete of the same quality as the poured concrete is also placed on this net material. A method for manufacturing a hollow prestressed concrete plate using type 2 lightweight concrete, characterized in that the concrete plate is poured into concrete and the surface thereof is pressurized by a certain part of the core rod.

Further, in order to achieve the above-mentioned object, in the method for producing a hollow prestressed concrete plate using the above-mentioned Type 2 lightweight concrete, the mesh material has a diameter of 1.5 to 3.
In some cases, the method is characterized in that it uses a mesh material made of 5 mm mild steel wire.

Further, in order to achieve the above-mentioned object, in the method for producing a hollow prestressed concrete plate using the above-mentioned Type 2 lightweight concrete, the mesh material has a diameter of 1.5 to 3.
In some cases, the method is characterized in that it uses a 5 m filament made of hard synthetic resin, or a net material made of a kind of wire material among twisted threads.

In addition, in order to achieve the above-mentioned problem, a hollow prestressed concrete plate, which is a rectangular plate as a whole, has several holes in the longitudinal direction, and tensed prestressed concrete steel is buried between these holes and on both sides. .

In the concrete layer between one side of the board and the several holes, the hole size is 60 mm x 60 mm.
A mesh material of 1100ne x 100n that is relatively hard to bend is buried, and the concrete is Type 2 lightweight concrete using structural lightweight concrete aggregate specified in JISA5002, and artificial lightweight aggregate is used as the coarse aggregate. An AE agent is added to an artificial light aggregate as a fine aggregate, and an ordinary fine aggregate and/or calcareous fine powder in an absolute volume ratio of 5 to 30% to the artificial lightweight aggregate, and slumped. Value 1.5 to 5
It is made of densely poured fresh concrete with a
The hollow prestressed concrete plate is made of Type 2 lightweight concrete, characterized in that the concrete is brought into close contact with the PC steel material and the mesh material and is integrated into the same material.

Further, in order to achieve the above-mentioned object, the material of the mesh material of the hollow prestressed concrete plate using the above-mentioned Type 2 lightweight concrete is formed from a wire rod made of one of mild steel and hard synthetic resin. A hollow prestressed concrete plate using type 2 lightweight concrete according to claim 4 is provided.

(Action of invention) Since there is no effect in the method invention, it will not be explained.

The effects of claims 4 and 5 apply to wall materials or flat roofing materials that are required to have insulation properties equivalent to those of ordinary class 2 lightweight concrete plates, higher load carrying capacity, and freeze-thaw resistance. Use as.

(Example) A method of a typical example of the present invention and an apparatus used in the method will now be described.

A is an example of a hollow prestressed concrete plate forming apparatus used in this method, which includes a long (usually 100 m to 1 som) form bed 11 with a horizontal top surface and a movable machine frame 15 that runs astride this. This movable machine frame 15 has two side formworks 16 extending in the longitudinal direction of the formwork bed 11 and a length of about 5 m to 10 m, and a base 17 is attached to the movable machine frame 15 between the both side formworks. , several core rods 18 extending horizontally rearward are supported and equipped in a cantilevered manner, and furthermore, in front of the bases 17 of the several core rods 18, above the core rods 18 are installed. , a first supply hopper 19 is provided, and a second supply hopper 20 is provided above the core rod 18, and the net material N is supplied between these first and second supply hoppers 19 and 20. A net material supply device 21 is equipped. The movable machine frame 15 also has several pressing rollers installed horizontally in the transverse direction of the form bed as a type of pressing device 22 for pushing downward the fresh concrete placed above the core rod 18 position. 23 and each core rod 18, and between the core rod 18 and both side plates 16, a pressing member 24 is provided which moves up and down.

The movable machine frame 15 may also be equipped with a vertically movable suppressing member 25 that presses the poured concrete between the first supply hopper 19 and the second supply hopper 20.

Next, an example of the composition of concrete used in this method invention will be explained.

If the composition is shown by weight in 1rr13 of mixed concrete, Example: Cement water / Cement Artificial lightweight fine aggregate (Mesarai ordinary fine aggregate (fine sand) Coarse aggregate (Mesalite) Fine sand / Mesalite 540, kg 185, kg 34, 3%)) 589 kg (specific gravity 1.9) 87, kg (specific gravity 2.52) 431, kg (specific gravity 1.65) Approx. 101% (absolute volume ratio) AE agent 180 cc (Vinzol registered trademark) 0. 033% (cement weight ratio).

Next, an example of the net material N used will be described.

The wire rod 25 constituting the net material N is made of mild steel and has a diameter of 2°6 mm.
The wire is woven into a mesh of 70mm+X100an.

Next, prepare a required length of PC steel material P with a diameter of 12°4I for introducing prestress.

A method for implementing the present invention will be specifically described using the above-described apparatus and materials.

First, in the longitudinal direction of the formwork bed 11, the required number of PC steel materials P are stretched between each core rod 18 and at positions on both sides, applying a predetermined tension using hydraulic jacks 13 at required locations, and each PC
Both ends of the steel material P are attached to the front and rear ends 12a, 1 of the formwork bed 11.
Fix it to 2b.

Next, the formwork bed 10 is attached to the net material supply device 21 of the movable machine frame 15.
A net material N having a length that can be laid over the entire length is set in the net material supply device 21, and the tip of the net material N is placed between the first and second supply hoppers 19 and 2.
It is passed over several core rods 18 from between 0 and fixed to the rear end 12b of the formwork bed 11.

Next, fresh concrete C having the composition described above is supplied to the first and second supply hoppers, and the movable machine frame 15 is slowly advanced.

In this way, the ready-mixed concrete C in the first hopper is sequentially supplied onto the form bed 11 on the advancing direction side from the base of the core rod 18, and as the movable machine frame 15 moves, the ready-mixed concrete C between the formwork 16 on both sides and several core rods 18
The amount of ready-mixed concrete C supplied from the first supply hopper 19 is adjusted so that a part of it reaches the upper surface of the core rod 18.

When the movable machine frame 15 is sequentially moved in this way, the pressing members 25 push the mold plates 16 on both sides, each core rod 18, and the PC steel P into the fresh concrete C sufficiently densely, and several cores Net material N is sequentially supplied onto the ready-mixed concrete that has been supplied to the upper side of the rod 18, and ready-mixed concrete C supplied from the second supply hopper 20 is supplied above the net material, and a pressing roller serving as a pressing device is further supplied. 23 and the pressing member 24, the ready-mixed concrete C is transferred to the formwork 12 on both sides.
It is filled around several core rods 18 and the PC steel material P between them, and the upper surface becomes a smooth surface.

As the movable machine frame 15 moves, the formwork 12 on both sides and the core rod 1
8, the ready-mixed concrete formed on the form bed 11 is sequentially removed from the concrete forming machine, and finally a hollow ready-mixed concrete plate is formed on the form bed with the required length of PC steel material P and mesh material N embedded. be done.

The ready-mixed concrete plate on the formwork bed 11 is heated by supplying steam to the passage in the formwork bed 11 for a predetermined period of time, and after curing with the heated steam, PCs fixed to both ends of the formwork bed are heated.
The steel material P is cut, prestress is introduced into the hollow concrete plate by contraction of the PC steel material P, and after a predetermined curing period, a hollow prestressed concrete plate is obtained.

In the above example, the mesh size of the mesh material N is 50me x 50mm as long as the coarse aggregate can easily pass through.
A small one, up to about m, is sometimes used.

The mesh material N may be made of mild steel, or may be made of synthetic resin as long as it does not bend much.

C0 Effects of the Invention Effects of the Method In the method invention described in claim 1, since the composition of the fresh concrete is as described above, it has excellent fluidity during pouring, and the pair of side frame templates 12 It is filled sufficiently densely without leaving any gaps between the core rods, between the PC steel materials, and between the core rod and the PC steel materials, and does not cause roughening of the sliding surface between the core rod and the templates on both sides. In addition, the upper layer of ready-mixed concrete that was supplied and formed on top of the core rod may collapse into the cavity after the core rod is removed due to the insertion of the mesh material, and the shoulders of both sides of the ready-mixed concrete plate that has been separated from the templates on both sides. The concrete hardens without causing any sag phenomenon, and without creating any voids around the prestressing steel material, while maintaining its shape during the curing time until the prestressing steel material is cut.

Therefore, even when the tension of the prestressing steel is released, the hardened concrete and the prestressed steel remain bonded together without separating. It can be definitely introduced.

Furthermore, by using ready-mixed concrete with the above-mentioned composition, fine aggregate is usually mixed in the ready-mixed concrete, albeit in a small amount, within the above range, so that the contact surfaces and surfaces with the formwork bed and both side templates are Also, a dense surface layer is formed without causing roughness.

In short, there are almost no large voids or communicating gaps other than the small closed cells formed by the AE agent, and the specific gravity excluding the cavity formed by the core rod is around 1.6 degrees, and the specific gravity including the cavity is approximately 1. Hollow prestressed concrete plates of 1.3 to slightly lower can be produced.

Furthermore, it has excellent heat insulation properties and freeze-thaw resistance, and can be made into a molded product with high strength in both bending and compression by integrating with the PC steel material and the filling material.

In the method of using mild steel as the netting material according to claim 2, a molded article particularly excellent in compression resistance can be manufactured.

In the method of using a hard synthetic resin netting material as described in claim 3, the effect during molding is no different from that of a mild steel netting material, but the specific gravity of the molded product is even higher. A molded product that is lightweight and whose mesh material does not oxidize even when moisture enters from the outside can be obtained.

When the value of the water-cement ratio is smaller than the range shown in claim 1, the fresh concrete is too hard and voids are formed around the prestressing steel, and when the prestressing steel is cut to introduce stress into the hollow concrete plate, Alternatively, there is a possibility that the concrete and the PC steel material will separate after that, making it impossible to introduce sufficient prestress into the concrete plate.

On the other hand, if the water-cement ratio is larger than the above range, the fresh concrete will be too soft, and during forming, the fresh concrete will deform in the cavity formed by the core rod or at the shoulder on the open side, making it impossible to form. becomes.

Furthermore, even if the water-cement ratio is within the above range, if the slump value is smaller than the above range due to the mixing of the AE agent, the fluidity of the fresh concrete will still be insufficient, and if it is larger than this range, the formed form will be retained. Can not.

Furthermore, if the ratio of normal fine aggregate to lightweight fine aggregate exceeds the above range, the specific gravity of concrete will increase significantly, and if it is less than the above range, the surface roughness phenomenon during forming will become noticeable and the bond with PC steel will deteriorate. The force also becomes weaker, making it difficult to introduce sufficient prestress.

Effects of the invention of the product The hollow prestressed concrete plate according to claims 4 and 5 manufactured by the method according to claims 1 to 3 above has a specific gravity of about 1.6 excluding the hollow portion. It has a specific gravity of about 1.3 when the hollow part is included, which is about half the specific gravity of a precast concrete board made of ordinary concrete. No outbreak.

In addition, because the specific gravity is small, if the concrete plate has the same weight as a conventional prestressed concrete plate, it can be twice as thick, which not only improves the insulation properties but also increases the moment of inertia due to the increased thickness. , the bending strength is improved and the support span can be increased.

In addition, since the bond between the PC steel material and the concrete is strong and sufficient prestress is applied, the concrete plate itself of the present invention has sufficient supporting force, and the conventional supporting structure steel can be reduced. This is a marked difference from Type 2 lightweight concrete, which could not be expected to have much supporting capacity as a building structure.

When the mesh material is made of mild steel, combined with the PC steel material, it has a high bending strength and does not cause cracking or peeling of the concrete.

For netting made of hard synthetic resin,
Furthermore, the specific gravity is low, so even if water that permeates from the surface reaches this net material portion, it will not corrode, and no cracks will occur due to corrosion of the net material.

Effects of Example Next, the results of a strength test of a hollow prestressed concrete plate manufactured by the method of the above example will be shown.

The cross-sectional shape of the molded product in the above example is shown in FIG.
An, 8 cavities 25 with a major axis of 130 mm and a minor axis of 124 nn are provided in the central part at a pitch of 162 mm in the length direction of the plate P
A sample was prepared by inserting 13 C steel materials with a diameter of 12.4 on and applying a prestress of 30 kg/cd.

Other freeze-thaw tests include ATSMC660-75
The experiment was conducted using method A.

However, the values in the table above are at the end of 100 cycles.

[Brief explanation of drawings]

The drawings show things related to the present invention, and FIG. 1 is a vertical cross-sectional schematic side view of an apparatus used in the method invention, FIG. 2 is a vertical cross-sectional front view of the core rod portion of FIG. 1, and FIG. −′ of the molded product
It is a sectional view showing an example. In the figure, 10... Molding device, 11... Formwork bed, 15... Movable machine frame 18...
... Core rod, N ...... Net material, P
・・・・・・・・・PC steel material, C・・・・・・Ready-mixed concrete.

Claims (1)

[Claims] 1) There is a long formwork bed with a flat top surface and a movable machine frame that runs astride this, and this movable machine frame has a vertical frame extending in the longitudinal direction of the formwork bed. Between the formwork on both sides, a device whose base is attached to the movable machine frame and equipped with several core rods extending horizontally to the rear is used. In the predetermined position between the core rods and on both sides,
A prestressed steel material is stretched on the formwork bed with a predetermined tension applied in the longitudinal direction of the formwork bed, mixed ready-mixed concrete is placed near the base of the core rod, and a part of the core is placed upwardly. While applying more pressure and running the traveling machine frame, a perforated fresh concrete plate is formed on the form bed, and after curing this fresh concrete plate until it develops a predetermined strength, the PC steel material is In the method of manufacturing a hollow prestressed concrete plate by releasing the connection with the formwork bed at both ends of the concrete plate, a) the composition of the ready-mixed concrete is Type 2 lightweight concrete using structural lightweight concrete aggregate specified in JISA5002. , artificial lightweight aggregate is used as the coarse aggregate, artificial lightweight fine aggregate is used as the fine aggregate, and normal fine aggregate and/or 5 to 30% by absolute volume ratio of the artificial lightweight aggregate are used.
or calcareous fine powder, using ready-mixed concrete with a water-cement ratio of 32 to 45%, and adding an AE agent to a slump value of 1.5 to 5 cm, b) First, each of the core rods The fresh concrete was placed and pressurized to the extent that the top surface was covered.
A net of 60 mm to 100 mm x 100 mm made of a material that is relatively hard to bend is sequentially laid on the surface of the freshly poured concrete in the area where the core rod is located, and a green cloth of the same quality as the freshly poured concrete is also placed on this net. A method for producing a hollow prestressed concrete plate using type 2 lightweight concrete, comprising: pouring concrete and pressurizing the surface with a certain portion of the core rod. 2) Cavity prestressed concrete using type 2 lightweight concrete as set forth in claim 1, characterized in that the net material is a net material made of mild steel wire with a diameter of 1.5 to 3.5 mm. Method of manufacturing the board. 3) The method uses, as the net material, a net material made of one of hard synthetic resin filaments and twisted yarns having a diameter of 1.5 to 3.5 mm. A method for producing hollow prestressed concrete plates using lightweight concrete. 4) In a hollow prestressed concrete plate that is a rectangular plate as a whole and has several holes in the longitudinal direction, and tensioned steel is embedded between the holes and on both sides, one side of the plate and In the concrete layer between the several holes, the mesh size is 60 mm x 60 mm to 1
A net of 00 mm x 100 mm made of a material that is relatively hard to bend is buried, and the concrete is Type 2 lightweight concrete using structural lightweight concrete aggregate specified in JISA5002, and artificial lightweight aggregate is used as the coarse aggregate. The AE agent is added to an artificial lightweight aggregate as a fine aggregate, and an ordinary fine aggregate and/or calcareous fine powder in an absolute volume ratio of 5 to 30% of the artificial lightweight aggregate. Type 2 lightweight concrete is made by densely pouring fresh concrete with a slump value of 1.5 to 5 cm, and the concrete is brought into close contact with the PC steel material and the mesh material, and is solidified and integrated. Hollow prestressed concrete board using concrete. 5) Cavity prestressed concrete using type 2 lightweight concrete as set forth in claim 4, wherein the material of the mesh material is formed from a wire rod made of one of mild steel and hard synthetic resin. Board.