JPH05156737A - Concrete construction by use of surface material - Google Patents

Abstract

PURPOSE:To lessen weight by reduction of the thickness of a member to correspond to a span structure, by utilizing a prestressed extruded member as a molding frame and burying it as it is as a surface member. CONSTITUTION:A fastening member 4 is inserted into pierced holes 2 of a mold member and protruding from the fixing hole of the fixture 3 attached to the both ends of the mold member. Next, nuts 6 are pushed in screws 5 to provide a posttension to the fastening member 4 for a prestressed extruded member. The prestressed extruded members 1 are laid down on a beam 7 of steel frame. And concrete is placed thereon to make a slab. In this way, the necessary volume for a support I can be reduced and the prestressed extruded member 1, utilized as a mold member after the concrete is cured, can be used for the surface member as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to concrete pouring using a formwork, particularly reinforced concrete (R
The present invention relates to a concrete construction method in which a prestressed extruded member is used as a mold and is directly embedded as a surface material in the construction method C and the steel frame reinforced concrete (SRC) construction method.

[0002]

2. Description of the Related Art In the RC and SRC frame construction methods for civil engineering and construction, the form material is used to fix the form frame, and then concrete is poured and the form frame is demolded after a certain curing time. The skeleton and the SRC skeleton were formed.

Usually, RC skeletons are fixed in a concrete frame by using a material for a mold, and then concrete is poured into the RC skeleton after concrete strength is exerted, except in a special case where concrete is directly cast on the ground. It is formed by demolding the frame.

The formwork is a temporary container, ie, a mold, for making concrete which will be a structure of a building, and retains necessary water during setting and hardening of the placed concrete to keep it from the influence of outside air. Has a role to protect.

The formwork consists of a weir board in contact with the concrete surface and horizontal flap material, vertical flap material, joists, large pulls, supports such as pillars, separators, foam ties, wood cones, etc. for supporting the concrete. It was necessary to assemble this before pouring, and to remove it after the concrete hardened, which made the work on the construction site complicated, resulting in poor labor productivity.

[0006] Concrete formwork is used in the construction site to form walls, columns, floors (the floor may be the ceiling from below), beams, etc. The floor construction method will be described below. ..

Reinforced concrete slabs are used in most cases as flooring materials for buildings other than Japanese houses, but these are roughly classified into cast-in-place concrete slabs and precast slabs.

In the cast-in-place concrete slab, after assembling the formwork, the reinforcing bars are arranged, the concrete is placed, and the formwork is fixed by supporting work until the concrete is hardened and the strength is exhibited. After a certain curing period, a slab can be made except for the formwork, but the surface needs to be finished.

On the other hand, a precast plate (P
This construction was attempted because if the (Ca plate) can be brought to the site and used as a floor material as it is, the formwork and supporting work will be eliminated, and the construction period can be shortened, labor can be streamlined, and productivity can be improved.

However, when using only PCa plate material,
After installation, PCa boards cannot be handled with each other due to misalignment or equipment piping, so that the location of use is limited, joint noise, water leakage, bending for horizontal force transmission, shear resistance to joints, etc. There was a problem. Furthermore, in order to meet the requirements for fire resistance and strength stipulated by the Building Standards Law, it becomes necessary to thicken the PCa plate, which in turn increases the weight of the PCa plate as a unit, limiting the span length and increasing the span. The PCa plate was not only heavy and poor in handleability, but also increased in manufacturing cost, construction cost, etc.

In recent years, in order to take advantage of the PCa board, a structure (deck plate construction method) has been tried in which a cast-in-place concrete construction method is applied using a steel deck plate used in a steel frame.

Generally, in the construction of a fireproof structure using deck plates, spraying a mixture of rockwool and cement on the exposed surface of the deck plates in order to meet the construction management standard value specified by the Minister of Construction. Is being done.

Since this work is carried out at the construction site while workers of other industries are working, not only is the work site confused, but environmental deterioration due to dust scattering during the spraying work is inevitable.

Therefore, a half slab method (also referred to as a synthetic slab structure or a half PCa plate method), which takes advantage of the advantages of precast and cast-in-place concrete, is being adopted while making up for such problems. The half slab method is a method of precasting the lower part and combining the upper part with cast-in-place concrete to complete the floor slab.

In this case, the points to be considered are
It can be mentioned that the precast plate (PCa plate) and the cast-in-place concrete are integrated, and the mechanical strength against various loads applied to the PCa plate generated when pouring fresh concrete is satisfied.

Since this method eliminates (or significantly reduces) formwork and supporting work, there is an advantage that the productivity of on-site construction is remarkably improved, the construction period is shortened, and labor is saved on site.
Also, unlike the PCa board construction method, there is a high degree of freedom in design support, which is advantageous in terms of cost.

However, since the PCa plate conventionally used in the half slab method is produced by a normal batch method, the productivity is poor, and the manufacturing technique of a large member to cope with a large span is difficult, and the There was also a problem with mechanical performance.

On the other hand, there are inorganic hollow extrusion moldings used for outer walls of buildings, partition walls, frozen warehouses, elevator shafts, double floors and the like. Since this member is manufactured by an extrusion method using a special compounding material, it has excellent physical and mechanical properties, extremely high productivity, and its shape can be freely selected.

Furthermore, since this molding material has a hollow structure, it is lightweight and strong, and also has sound insulation properties, and many of them have been designated as fireproof structures and sound insulation structures, and are widely used as building materials and civil engineering materials. .. Examples of commercially available products include Lambda [Showa Denko Kenzai Co., Ltd.] and Mace [Mitsubishi Cement Kenzai Co., Ltd.].

The extruded member is superior in bending and compressive strength to the commercially available PCa material for half slabs.
If a member cracks due to an unexpected impact load, it is assumed that the PCa plate may fall, and it cannot be put to practical use under the current conditions.

[0021]

An object of the present invention is to develop a new concrete construction method which overcomes the problems of conventional construction methods such as cast-in-place concrete slab construction method, PCa board construction method, deck plate construction method and half slab construction method.

[0022]

According to the present invention, a steel material or a fibrous material is inserted into all or part of a groove or a through hole as a binding material in an extruded material of a hydraulically hardened kneaded product having a groove or a through hole. The concrete is characterized in that it is formed into an extruded member by prestressing it in the axial direction by post-tensioning, and the extruded member is used as a formwork to cast concrete, and is embedded as it is as a surface material, and this extruded member is used as a surface material. The problem was solved by developing a construction method.

In the present invention, an extruded member having a groove or a through hole is indispensable, and a binding material is inserted into all or a part of the groove or the through hole of the extruded member manufactured or commercially available for this purpose so that the extruded member has an axial direction. It uses a prestressed extruded member with post-tension.

This prestressed extruded member is shown in FIG.
A structure as shown in is acceptable. The extruded member 1 is obtained by extruding mortar mixed with cement, aggregate and the like from a nozzle as a mold material having a through hole or groove by an extrusion method, cut into an appropriate length and cured, and further cured by autoclave or steam. It is the mold material 1 which is completely cured by the above.

This member is superior in mechanical properties such as very high bending and compressive strength to conventional PCa members, and is also excellent in corrosion resistance and waterproofness. Furthermore, the adhesion performance with concrete is good. Moreover, the member can be made thin and large in size.

Further improvement can be made by adding various additives to the mortar for increasing the strength. For example, a cement produced by adding an aggregate, various additives, and a heat-crosslinking melamine resin to the mixture, molding it, and then heat-treating it (JP-A-62-182)
144), a system in which a certain amount of a synthetic polymer emulsion is mixed with a powder composition composed of cement, aggregate and various additives (the synthetic polymer emulsion here is a normal emulsion). Although it may be used, an acrylic resin dispersion having a small particle size, that is, an average particle size of 100 nm or less and a dense three-dimensional mesh network structure is preferable.) And those containing bhopal resin.

The flexural and compressive strength of the composition molded body containing these additives is 3 to 4 that of conventional concrete and mortar.
It is possible to significantly reduce the thickness of the material compared to conventional products, and it is a completely non-combustible material and has excellent durability such as neutralization, waterproofing, and freeze-thawing.

As the binding material 4 to be inserted into the through hole 2 or groove of the mold material, PC used for binding material of PC material is used.
Steel wire, deformed PC steel wire, PC stranded wire, PC steel rod, deformed P
Examples include C steel rods, high-strength fibers such as carbon fibers and aramid fibers.

A binding material (a PC steel rod with a screw 5 cut at both ends) 4 is inserted into a through hole 2 (a groove when the groove is a groove) of the mold material 1, and a fixing hole for a fixing tool 3 attached to both ends of the mold material. Then, a nut 6 is screwed into the screw 5 to apply a post tension to the binding material 4 to form a prestressed extruding member. By doing so, the extruded member is further strengthened.

Providing post-tension in this way not only further improves the bending crack strength, which is a characteristic of the extruded member, but it should be noted that impact resistance of the extruded member, that is, panel drop due to cracks, etc. It is in the point that the danger was greatly improved.

In this case, in order to improve the adhesiveness between the extruded member and the cast-in-place concrete, it is preferable to provide a sheer cotter or the like on the surface of the extruded member which comes into contact with the concrete to be cast, as shown in FIG. 3, because the adhesiveness is improved.

Since this prestressed extruded member has high mechanical properties, it can be used as a form material and concrete can be poured as it is to form a floor structure.

That is, if the prestressed extruded member 1 is spread on the steel beam 7 as shown in FIG. 4 and concrete is cast on the beam as shown in FIG. 5 to form a slab, the amount of supporting work required is also increased. The prestressed extruded member used as a mold material after being reduced and the concrete is hardened becomes a surface material (ceiling material) as it is, and the man-hour for removing the mold is not necessary. In addition, the work of blowing rock wool, which causes confusion and environmental pollution at the site, such as deck plates, can be omitted.

[0034]

The present invention is based on the finding that mechanical properties are improved by prestressing an extruded member having high productivity and capable of producing a free shape by post tension.

If the prestressed extruded member is used as a surface material for concrete, it goes without saying that the effects of labor saving, rationalization and improvement of productivity can be obtained.

Although only the floor construction method has been described for the sake of convenience of description, it goes without saying that it can be similarly used for walls, columns, beams and the like. In the case of pillars, beams, etc., the panel of the prestressed extruded member may be used as a form or a form of the surface part of the exposed surface to surround the periphery, and concrete may be poured into the interior to form columns or beams. However, it is also possible to use the prestressed extruded member on the column as a beam member for exposing.

[0037]

[Example] Thickness 55 mm, width 492 mm, length 5000
mm autoclave cured extruded concrete member (Lambda 55, Showa Denko Kenzai), 17 mmφ as binding material
7 PC steel rods at approximately equal intervals are passed through, and a fixing tool and a nut are used to apply a tension of 30 Kg / cm ² (per cross-sectional area) to prepare a pre-stressed extruded member, 4 m ×
A 5 m slab was formed. For comparison with this, the number of man-hours by the cast-in-place concrete slab method of the same area was compared.

When the method of the present invention was used, it took only 2.3 man-hours to assemble the mold and no demolding was required, whereas in the cast-in-place concrete slab method, 3.2 man-hours were required to assemble the mold. It took a total of 4.4 man-hours to remove the mold, 1.2 man-hours.

[0039]

EFFECTS OF THE INVENTION By using a hydraulically kneaded product extruded member which is prestressed in the cast-in-place concrete method as a surface finishing material, it is possible to obtain excellent mechanical properties, especially bending crack strength. It has become possible to reduce the weight and support the span structure. In addition, by applying post tension, safety and reliability during and after construction were greatly improved. There is no need for a construction method that uses a mold material such as plywood or metal, which has been conventionally used at the time of placing concrete, and therefore a mold removing work is unnecessary. Since the support work can be largely omitted, a wide working space under the floor can be secured, and the mechanization and efficiency of the work can be promoted. It could be used as a surface finishing material because of its various physical properties, especially the surface condition of high density and dense, and smooth surface. Labor saving has been achieved by improving the work environment, significantly shortening the construction period, and significantly reducing the construction man-hours.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a prestressed extruded concrete member.

FIG. 2 is a plan view of a prestressed extruding member.

FIG. 3 is a cross-sectional view of an extruded member whose surface is shear-cottered.

[Fig. 4] Fig. 4 shows an installation situation of a form made of a prestressed extruded member before placing concrete.

FIG. 5 shows a cross-sectional view of a synthetic slab using a prestressed extruded member.

[Explanation of symbols]

 1 Extruded Member 2 Through Hole 3 Fixing Tool 4 Tightening Material 5 Screw Thread 6 Nut 7 Beam 8 Concrete

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location E04B 5/43 A 9127-2E E04G 21/12 104 E 7228-2E

Claims (2)

[Claims] 1. A steel material or a fibrous material as a binding material is inserted into all or part of a groove or a through hole as an binding material to an extruded material of a hydraulically kneaded product having a groove or a through hole, and a pre-tension is preformed by post tension in the axial direction. Apply stress to form an extruded member, place concrete using this extruded member as a mold,
A concrete construction method characterized by embedding as it is as a surface material and using this extruded member as a surface material. 2. The concrete construction method using a surface material as a formwork according to claim 1, which is a prestressed extruded member having an uneven surface for placing concrete.