JP2717332B2 - Prestressed extrusion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved prestressed concrete (hereinafter sometimes abbreviated as PC) member used in the fields of civil engineering and construction, and a method of manufacturing the same.

[0002]

2. Description of the Related Art PC members are used in bridges, paved roads, runways, tanks, reactor vessels, marine structures,
It is used as a material for a wide range of fields, such as towers, gymnasiums, factories, and parking lots. It is also used in the fields of electric poles, sleepers, concrete pipes, handrails and the like as secondary products produced in factories.

[0003] There are two types of PC member manufacturing methods, one is a post-tension system mainly employed in the method of casting concrete in-situ, and the other is a pre-tension system mainly produced by a factory.

[0004] In this pretensioning method, a binding material is tensioned on a tension table before concrete is poured, a formwork is arranged around the binding material to which a tensile force is applied, and concrete is struck. When the compressive strength is reached, the binding material is cut off to form a PC member.

[0005] The concrete slump used in this method uses hard concrete of 0 to 8 cm in order to increase the strength, so that it is difficult to knead, drive, mold and so on. There is a problem in that the shape of the member is limited due to the necessity of forming a mold, and the productivity is extremely low since the production is performed in a batch system.

The concrete used here has a low strength because a general-purpose composition is used, and in order to increase the strength, the thickness of the member must be increased. Therefore, when it comes to large products, PC
Since it is difficult to carry the members on site, restrictions are imposed on the span length and thickness of the product, and a heavy PC member exceeding this will cause a great obstacle in terms of on-site carrying and construction.

On the other hand, there is a precast cement member (PCa member) used as a building material separately from the PC member. Among them are cement extruded members, which are used for building outer walls, partition walls, freezer warehouses, elevator shafts, double floors, roofs and the like.

[0008] The extruded member is manufactured by extruding a mortar containing cement, aggregate and a special additive as a mold using an extruder, cutting it into a predetermined length, and performing autoclave curing or steam curing. is there.

Therefore, the productivity is very high, the mechanical properties are excellent, and it is suitable for the production of a flat plate, a tube or a mold having various shapes having through holes or grooves.

The extruded member has a hollow structure, so that it is lightweight. Further, the mortar used is not a general-purpose composition and is extruded by being compressed at a higher pressure and is completely cured. It is a member having extremely high strength, and has a higher strength than a commercially available PCa material. Such extruded members are excellent in heat insulation, weather resistance, and frost damage resistance, and some of them are designated as fire-resistant and heat-insulated structures, and are widely used as building materials and civil engineering materials.

However, the extruded member is subjected to an unexpected impact load, and if cracks occur, there is a danger of breakage or dropping.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a high-strength prestress extruded member which is hardly cracked by an impact or the like, has no danger of breaking or dropping, is lightweight, has a simple manufacturing process, and has high productivity. For development purposes.

[0013]

According to the present invention, there is provided a fixing device which has a plurality of fixing holes covering both end surfaces in the axial direction of a hydraulic kneaded extruded material having grooves or through holes. A plurality of steel or fiber binding materials are inserted into all or a part of the groove or through-hole through the groove or through-hole of the extruded material and the fixing hole of the fixing device, and are inserted into the end face of the extruded material. Developing a prestressed extruded member characterized by uniformly applying a prestress in the axial direction, and a prestressed extruded member as described above, in which mortar is filled in through holes or grooves of the prestressed extruded member. Solved the above problem.

In the present invention, the extruded member is obtained by extruding a mortar from a nozzle as a mold having a through hole or a groove by an extrusion method, cutting the mortar into an appropriate length, and then curing the mortar by autoclaving or steam curing. Means that the profile was completely completed.

When extruding, the mortar is strongly compressed and extruded, so that the mortar body is more densely packed than in the case of general casting. The strength is high.

In particular, the mortar usually used in the extrusion method contains cement, aggregate, and a thickener and other special additives for improving the formability and physical properties of the product. ing.

Further, a thermally crosslinked melamine resin (Japanese Patent Laid-Open No. 62-182144), a synthetic polymer emulsion (average particle diameter is 100 nm or less, acrylic resin having a three-dimensional network structure inside the particles) is added to the mortar of the present invention. One of the preferred methods is to use a composition in which a reinforcing agent such as a body) and a polyvinyl alcohol resin are blended.

As such an extruded member, a commercially available inorganic hollow extruded member used for an outer wall, a partition wall, a freezing warehouse, an elevator shaft, a double floor, a roof, etc. of a building is used. Is also good.

As the binding material to be passed through the through hole or the groove of this mold material, a PC steel wire used for a PC member, a deformed PC
Examples thereof include steel wires, PC steel strands, PC steel bars, deformed PC steel bars, and high-strength fibers such as carbon fibers and aramid fibers.

As described above, the extruded member has excellent mechanical properties by itself as compared with the conventional PCa member. However, by adding post tension thereto, the extruded member can reduce the bending crack strength which is a disadvantage common to concrete members. Can be significantly improved. By giving the post tension the same degree as that of the conventional PC member (for example, at most 30% of the compressive strength), the physical properties can be improved, and the impact resistance and the suppression of the occurrence of cracks can be greatly improved.

Hereinafter, the present invention will be described in detail with reference to the drawings for a plate-shaped extruded member. FIG. 1 is a cross-sectional view of a through-hole portion of an extrusion member 1 having a plurality of through-holes 2. A multiple- piece PC steel material having threaded portions 5 at both ends in this through hole 2
The Tightened material 4 having to cover the entire surface of both ends of the extruded member 1, and inserted in whole or in part of a plurality of fixing holes fixing member 3 of the fixing hole 33 having a set to leave come collision from both ends (FIG. 2). A nut 6 is fixed to the fixed side of the screw portion 5 with a screwing fixing jig 7 (FIGS. 3 and 4), and the nut 6 is also screwed and tightened on the tightening side to give tension to the binding material 4, thereby extruding the extrusion member 1. Stress. When the tension reaches a predetermined tension, the fixing jig 7 is removed to obtain a prestressed member (FIG. 6). This plan view is a plate-shaped mold member as shown in FIG. 6, and several types of fixing tools 3 can be considered at this time. For example, the fixing tool 3 has a shape as shown in FIG. An upper rib 31 having a surface in contact with the wall portion and having a shape such that prestress is uniformly applied to the entire end face of the molded body;
It includes a lower rib 32, may be provided with the plurality of solid Teiana 33 corresponding to a plurality of through-holes 2 of the molded body.

In the above description, the extruded member has been described as an example having a through hole. However, an extruded member having a groove as shown in FIG. 8 or an extruded member in which a groove and a through hole are mixed may of course be used. Will be easy to understand.

Further, PC is inserted into the through hole or the groove of the extrusion member.
Fixing the binding material of steel, but after setting the binding material for rust prevention and fireproof coating of the steel material, grout cement paste with good fluidity and appropriate expansion property in the space of through holes or grooves. Alternatively, the use of cement mortar is preferred.

[0024]

The PC member tensions the PC steel material and prestresses the concrete member, thereby preliminarily applying a compressive force to the tension side of the concrete member in advance.
The purpose is to improve the tensile strength and bending crack load, which are the weak points of concrete.

According to the present invention, a binding material is passed through a through-hole or a groove of a high-strength cement extruded member having a through-hole or a groove as a concrete member, and a fixing device is set at both ends of the extruded member. To give a prestressed extruded member.

[0026]

[Example] thickness 55mm, width 492mm, length 2200
mm of Autoclaved extruded concrete member (lambda 55, manufactured by Showa Denko building materials) substantially through equal intervals seven a PC steel rod 17mmφ as Tightened material, using the fixing member and the nut, to which 30 Kg / cm ² (cross-sectional area Per) and a tension of 45 Kg / cm ² .

For comparison, a cast-in-cavity prestressed concrete panel cut to the same dimensions was prepared, and a prestressed concrete panel was prepared in the same manner as in the example. These test pieces were subjected to a quadrilateral two-point load in accordance with the simple blush test according to JIS A1414. The span is 2
The bending crack load was measured at 00 cm. Table 1 shows the results.

[0028]

[Table 1]

[0029]

According to the present invention, an extruded member having high productivity and a free shape can be manufactured, and mechanical properties are particularly excellent among PCa members. It has been found that the following effects can be obtained. The weight is reduced by the reduction in the member thickness, and the handleability is improved. By using a material that is superior in bending crack strength, it is possible to cope with a large span structure. Since the bending crack load increases, the occurrence of cracks can be suppressed, and an unexpected impact load can be handled. By selecting the prestress value, it is possible to adapt to the span structure according to the site specification without changing the member thickness.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an extruded member (a panel shape as an example). Hereinafter, the manufacturing process is shown up to FIG.

FIG. 2 shows a fixing device and a binder.

FIG. 3 is fixed by a nut.

FIG. 4 is fixed by a fixing jig and tightened by a nut.

FIG. 5 is a completed (cross-sectional) view of a prestress extruded member.

FIG. 6 is a plan view of FIG. 5;

FIG. 7 is a conceptual diagram of one of the fixing tools.

FIG. 8 is an example of a grooved extrusion member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extrusion member 2 Through hole 3 Fixing tool 31 Upper rib 32 Lower rib 33 Fixing hole 4 Tightening material 5 Screw part 6 Nut 7 Fixing jig

Claims (2)

(57) [Claims] 1. An extruded material of a hydraulic kneaded material having a groove or a through hole , covering both end surfaces in the axial direction , and covering the entire end surface;
Inserting a fixing device having a plurality of fixing holes provided, a plurality of the Tightened material steel or fiber material through the extrusion grooves of the molding material or the through-hole and the fixing hole of the fixing member, the whole or a part of the grooves or the through-hole and prestressing pushing member, characterized in that gave flop restless axially on the end face of the extrusion material. 2. The prestressed extruded member according to claim 1, wherein the mortar is filled in a through hole or a groove of the prestressed extruded member.