JPH068527B2 - Permanent formwork - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a permanent formwork for protecting a reinforced concrete structure from the action of harmful substances such as chlorine in seawater, and particularly to a plurality of cement forms. Chloride ions to a reinforced concrete structure that is a "implanted formwork" that is formed by forming an impermeable film between each of the material plates and is piled up, especially at the coast or near the river mouth. The present invention relates to a permanent formwork capable of semi-permanently preventing the intrusion of the like and protecting the reinforced concrete structure from destruction.

[Prior Art] In a reinforced concrete structure installed in the ocean or a coastal area, the rebars affected by the action of chlorine ions in seawater corrode. This corrosion causes the reinforcing bars to expand and cracks in the concrete. As a result of inviting a larger amount of chloride ions, the expansion of occlude due to corrosion of the reinforcing bar further progresses, the durability of the reinforcing bar decreases, and the concrete structure is destroyed. Therefore, in order to prevent such a state, various measures have been conventionally taken for the purpose of preventing or delaying invasion of chlorine ions in seawater, and there are also the following measures. That is, (i) the formation of an organic film on the surface of the concrete to be poured, (ii) the use of a cement-based permanent formwork at the time of placing the concrete, resulting in an increase in the overburden thickness on the reinforcing bar. The intended method, etc.

A permanent formwork is used as a formwork during concrete pouring, but it has the purpose of protecting the concrete for a long period of time by being integrated with the concrete without being removed from the mold even after the concrete hardens. It is what is said.

[Problems to be solved by the invention: Object of the present invention] The prior art of (i) has poor weather resistance when it is present on the surface of concrete on which a simple organic coating is cast,
Alternatively, since the physical resistance to the action of seawater is particularly weak, the film is damaged in a short period of time, so that it is possible to prevent the invasion of harmful substances such as chlorine ions in seawater for a long period of time. There is a problem or a drawback that it does not exist.

The conventional technique of (ii), because the cement-based permanent formwork is not impermeable to water from a microscopic point of view, it merely brings about the effect of thickening the “fog” on the reinforcing bars in the concrete. , Therefore, the effect of delaying the intrusion of chlorine ions etc. in seawater for a short period of time can be obtained, but it is not permanent, and eventually the reinforcing bar is eroded, and the poured concrete will eventually be destroyed. There is a problem that is.

[Means for Solving Problems: Configuration of the Present Invention] As a result of intensive research to solve the problems of the above-mentioned conventional techniques, chlorine is formed by forming an impermeable film in the permanent mold. The inventors have found that it is possible to prevent ions from entering reinforced concrete, and have completed the present invention.

The permanent formwork according to the present invention is a so-called "driving formwork", which is characterized in that a plurality of cement-based material plates are superposed, and an impermeable film is formed between the respective plates. is there.

Next, as one embodiment thereof, a pair or more of the respective overlapping surfaces of the cement-based material plates have an uneven shape with respect to the surfaces, and the pair of matching surfaces are substantially fitted to each other. That is what you do.

In still another embodiment, the concave-convex shapes that are fitted to each other are expressed in terms of the recess, where the shortest distance between the perpendicular to the plate surface and the deep portion of the side end line of the recess passing through the center of the recess. Similarly, the shape is such that it is larger than the shortest distance to the shallow portion, that is, the deep portion in the concave portion is laterally sculpted.

Hereinafter, the present invention will be described in more detail. First, as the order, the above-mentioned constitution of the permanent mold of the present invention will be added, and then the method for producing the permanent mold of the present invention will be described. Of the method of manufacturing and constructing a reinforced concrete structure using a formwork, the concrete construction part will be described.

First, cement, which is a cement-based material, is an inorganic glue.
Various cements such as Portland, blast furnace, fly ash, etc. are included, and the permanent formwork of the present invention includes mortar or concrete using one or more of these, and materials mixed with fibers such as alkali resistance. .

Further, in the present invention, various adhesives can be used as the film forming material as the material of the water impermeable film formed on the mating surface of each cement-based material plate. Of these, synthetic resin-based paints are preferably used in consideration of water tightness. For example, polyamide, polyester, polyethylene, polypropylene, epoxy, methacryl, polyvinyl acetate resin and the like.

Since the watertightness of the film formed on the permanent mold according to the present invention is lowered when it is too thin, it is desirable that the film be 0.1 [mm] or more.

Further, the permanent formwork of the present invention is a stack of a plurality of cementitious material plates having the impermeable coating sandwiched between the mating surfaces, but this number may be any number of two or more, and many The higher the number, the higher the quality. It is possible to select the number of sheets depending on the situation of the construction site and the economical efficiency.

Further, as described above, it is more preferable that at least one of these overlapping surfaces has an uneven shape with respect to the surfaces. This is to prevent separation from the portion of the water impermeable film. .

Furthermore, the deep portion of the concave-convex concave portion is, so to speak, a very large resistance to the peeling force.

Furthermore, the permanent formwork of the present invention preferably has an uneven shape, that is, an irregular shape, on the surface that contacts the cast concrete. This is because the irregular shape strengthens the adhesion between the permanent formwork and the cast concrete.

The permanent mold of the present invention can have a synthetic resin film formed on the surface in contact with concrete or on the outer surface. This is because it is possible to prevent chlorine ions from entering the seawater for a longer period of time.

Next, a method for manufacturing the permanent mold of the present invention will be described. It can be extruded or pressed. The reason for the extrusion molding method is that the surface of the cement-based material plate produced by the extrusion molding method is uniform and smooth. In the extrusion molding method, since a material having a low water-cement ratio is used, excess water does not float on the surface after molding. Therefore, it is possible to form a film without peeling of the surface.

In the extrusion molding method, it is possible to arbitrarily produce a cement board having an irregular shape, for example, a corrugated shape at right angles to the extrusion method. In particular, it is suitable for manufacturing a deformed mold by adding a reinforcing material such as alkali resistant fiber.

On the other hand, in the pressure molding method, it is possible to further reduce the water-cement ratio, so if the amount of cement used is the same, if the form plate with even greater strength is used, or if the strength is the same, It is possible to manufacture thinner and lighter formwork plates.

However, although the extrusion molding method is highly efficient for continuous molding, it is difficult to make discontinuous holes in the mold surface, and the pressure molding method has discontinuous holes or deep recesses. Although the above-mentioned "deformed shape" is possible, continuous molding is somewhat inconvenient and has advantages and disadvantages. Therefore, it is desirable to select a manufacturing method according to the desired shape.

The impermeable film is formed by applying the film material to be formed on one surface of the hardened plate and one of the cement-based material plates,
It is possible to manufacture by adhering and cementing one of the cement-based material plates. At this time, it is also possible to apply the coating material to one surface of both cement-based material plates and then bond the surfaces coated with the coating material to each other.

In order to form a film between the cement-based material plate and the cement-based material plate, in addition to the above method, for example, after forming a film on the surface of one or both of the cement-based material plate with a paint or the like, this and the other or There is a method of bonding the cement-based material plates to each other by pressure bonding or an adhesive material.

In the present invention, as the film forming material, an adhesive that cures at room temperature or a relatively low temperature, or a material that melts at a relatively low temperature and solidifies after cooling can be used. For example, as the adhesive material, epoxy resin type, polyester type,
Polyamide, polyvinyl alcohol, acrylic resin or the like is used, and asphalt can be used as a material that is melted and then cooled and solidified. In particular, tar epoxy can be preferably used. Natural and synthetic rubber latex can also be used.

Next, a method of placing concrete using the permanent formwork of the present invention will be described.

When concrete is cast using the permanent formwork of the present invention to construct a marine or coastal reinforced concrete structure, it is desirable that the permanent formwork and the concrete are integrated. In the present invention, the surface of the permanent formwork which comes into contact with concrete can be made uneven as shown in FIG. By this measure, the concrete and the permanent formwork can be integrated. Further, as shown in FIG. 3, the cemented material plate can have an uneven bonding surface.
By this measure, the permanent formwork can be made stronger.

The permanent formwork of the present invention is laid on the surface of the structure which is in contact with seawater or the surface of which the influence of seawater such as floating seawater floats when constructing the structure by placing concrete. After laying the permanent formwork, perform the specified work and place concrete.
After hardening of the concrete, the reinforced concrete and the permanent formwork are integrated so that the permanent formwork blocks the invasion of chlorine ions in seawater into the concrete and permanently protects the reinforced concrete.

[Operation of the present invention] Since the permanent formwork of the present invention is one in which a water-impermeable control film is formed between each of a plurality of cement-based material plates, it is used for concrete pouring and As a "formwork",
In the case of integration, since the water impermeable film is protected between the cement-based material plates, it is impacted by the aggregate when driving concrete into the concrete, or the sand in seawater waves remains after the construction. Since it is not damaged by coarse particles or coarse suspended matter, this impermeable layer can prevent invasion of chlorine ions and other harmful substances in seawater for a long period of time. In particular, in the aspect in which the mating surface of the cement-based material plate is provided with irregularities, and the surface in contact with the cast concrete is irregularly shaped, each surface hardly peels off, so that the above-mentioned action is almost permanent. It is possible to prevent the reinforcing bars in the reinforced concrete from being corroded by chlorine ions, etc., thereby making the life of the concrete semi-permanent.

〔Example〕

Common matters for each of the following examples and comparative examples are as follows.

"Combination of cement material board" Cement (ordinary Portland) 60 [weight ratio] Sand (fine silica sand) 37 [weight ratio] Reinforcing fiber (alkali resistant glass fiber) 3 [weight ratio] Thickener 1 [weight ratio] Water 29 [weight ratio] [Mixing of concrete for casting] Cement (ordinary Portland) 318 [kg / m ³ ] Fine aggregate 740 [kg / m ³ ] Coarse aggregate 1,072 [kg / m ³ ] Water 176 [ kg / m ³ ] Air-entrained admixture 0.6 [kg / m ³ ] When placing concrete, length 1,000 [mm], width 600 [m
m] and a depth of 300 mm, a permanent formwork was placed on the bottom of the steel formwork, and was placed on it.

A water permeability test and an adhesive strength test were performed using the specimens collected from the respective examples and comparative examples.

The water permeability test was carried out according to the test method of JIS A 1404 cement waterproofing material for construction, and the adhesion test was carried out by the Kenken-type adhesion test.

(Example 1) Using a cement-based material plate formed by an extrusion molding method using mortar kneaded with the above-mentioned cement-based material plate, the shape shown in Fig. 1 has a length of 1,000 [mm] and a width of 600
A permanent mold having a thickness of [mm] and a thickness of 500 [mm] was produced. The film forming material is tar epoxy, and the film thickness is 0.5 [mm].

FIG. 1 is an end view of the permanent formwork 1 of this example, which is formed by stacking flat cementitious material plates 2 and 2 ′ and sandwiching a water impermeable film 3 on the mating surfaces. The results of the adhesion test are shown in Table 1 below, in comparison with other examples. Since the cement-based material plate used is a flat plate, the adhesive force is 13.4 [Kgf /
cm ² ], but the water permeability was 0 [cm / sec], which was a very good result.

(Example 2) In this example, the material is the same as in Example 1, but the permanent formwork of this example uses a modified cementitious material plate on the side in contact with the cast concrete. FIG. 2 shows an end view of the permanent mold 5 manufactured by an extrusion molding method, and 6 is a deformed cement-based material plate.

The other symbols are the same as those in the first embodiment.

The uneven surface, that is, the surface in contact with the concrete to be placed, is installed on the bottom of the steel form frame of 1,000 [mm] in length, 600 [mm] in width, and 300 [mm] in depth, and concrete is placed from the top. . After demolding this one day later, cure it indoors for 40 days,
It was submitted to the test. As shown in Table 1 below, in this example, a modified cementitious material plate was used on the side of the cast concrete, and the adhesive strength was strong and the water impermeability was the highest.

(Embodiment 3) Also in this embodiment, the material is the same as in Embodiments 1 and 2, but the permanent formwork 10 of this embodiment has a cement-based material plate 11 having an uneven shape that fits with each other at the mating surfaces. , 13 is formed by sandwiching a water-impermeable film 12 between them. The size is also Example 1
In the same manner as above, this permanent formwork was placed on the bottom of the steel formwork, and concrete was placed on it. The adhesive force was 13.2, which was slightly weak, but the water permeability coefficient was 0 [cm / sec], which was extremely good.
This permanent mold is characterized in that the cement-based material plates 11 and 13 of the mold itself have large peel resistance.

(Embodiment 4) As shown in the perspective view of FIG. 4 (a), the permanent formwork 15 of this embodiment has a cement-based material having a mating surface with an uneven surface for fitting with each other.
A water-impermeable film 17 is sandwiched between 17 and 16, and the upper side, which comes into contact with the cement-based material-casting concrete, is formed in a deformed shape. Further, on the front side and the rear side of the same permanent mold, these concave and convex shapes and irregular groove shapes are formed with the directions of inclination being opposite. This shape is made by pressure molding method, first the lower cement-based material plate and the upper cement-based material plate are made separately, and the above-mentioned impermeable film is interposed between them, and this adhesive It can be formed by bonding the upper and lower plates together at the mating surfaces. As another manufacturing method, the lower cement-based material plate is made by a pressure molding method, and the mortar containing alkali-resistant fibers is poured immediately after kneading after forming a water-impermeable film in the concave portion of the upper surface, and the upper surface thereof Is pressure-molded so that In this method, since the mortar spreads through the impermeable film all the way to the concave part of the lower cementitious material plate, the lower cementitious material plate adheres to each other, and the peeling resistance is even greater. There is an advantage to be. As shown in Table 1 of the comparative table described later, the permanent mold of this example has a very strong adhesive force and the highest water impermeability. In addition, as described above, the concave and convex shapes and the slanting of the irregular groove shape are formed to be opposite to each other, so that the resistance force against the peeling force in the straight upward direction is very large, and in any of the obliquely upward directions. Even so, the peeling resistance is large, and the resistance to circumferential force is also large.

(Comparative Example) A hardened body of concrete alone was prepared in the same manner as in each of the above Examples, and simultaneously a water permeability test and an adhesion test were performed.
The test results are compared with the test results of the above-mentioned respective examples, and the first
These are shown in the table.

In addition, in the adhesive force test, the concrete part was broken in Examples 2 and 4 and the comparative example, and the boundary between the permanent formwork and the concrete was broken in Examples 1 and 3.

[Effects of the Present Invention] (1) The permanent formwork of the present invention is effective for preventing the influence of seawater such as the surface of reinforced concrete that comes into contact with seawater and the surface that is splashed with seawater when constructing a concrete structure in the ocean or coastal area. When used as a formwork in places, it prevents the entry of chlorine ions in seawater into the concrete and protects the reinforcing bars from corrosion due to chloride ions, which makes the life of the concrete structure permanent.

(2) Since the permanent formwork of the present invention is closely protected by the cement-based material plate before and after the main water-impermeable coating, sand in seawater can be used when the concrete is poured, or even after construction. Since the impermeable film is not damaged by suspended matter such as dust and coarse dust, the effect of almost completely meeting the purpose of semi-permanently protecting reinforced concrete is remarkable.

(3) In particular, among the permanent molds of the present invention, the cemented material plate has a mating surface with an uneven shape, is bonded through a water-impermeable film, and has a deformed surface in contact with the cast concrete. It has a large force, is extremely impermeable to water, and withstands peeling force in any direction, so that it is possible to semipermanently prevent harmful substances such as chlorine ions from entering concrete. Therefore, it brings great effects not seen in the prior art, such as being suitable for coastal construction in the open ocean where rough waves are pulled and pulled and complicated repeated loads are applied.

[Brief description of drawings]

FIG. 1 is an end view of a permanent formwork according to the present invention in which a water-impermeable film is formed between two flat plates of cement-based material, and FIG. FIG. 3 is an end view of the permanent formwork of the present invention using the cement-based material plate described above. FIG. 3 is an end view of the cement-based material plate in which the mating surface of the cement-based material plate is formed in an uneven shape and a water-impermeable film is attached. FIG. 4 (a) is a perspective view of the permanent formwork of the present invention, in which the cemented material plate has a mating surface with an uneven shape to hold a water-impermeable film, and the surface of the cast concrete has a deformed shape. FIG. 4 (b) is a sectional view taken along the line BB of FIG. 4 (a). 1,5,10,15 ... Permanent formwork, 2,2 ', 6,11,13,16,18,18' ... Cement-based material plate, 3,12,17 ... Impermeable coating

Claims (3)

[Claims] 1. A "pour-in form" for pouring concrete, which is formed by stacking a plurality of cement-based material plates and forms an impermeable film between each of the plurality of cement-based material plates. Permanent formwork characterized by that. 2. The permanent formwork according to claim 1, wherein at least one pair of the superposed surfaces of the plurality of cementitious material plates has a concavo-convex shape that substantially fits each other. . 3. The concave portion of the concave-convex surface to be fitted is a groove or a hole, and the shape of the cross section perpendicular to the mold surface and transverse to the longitudinal direction of the concave portion is at least one of them. The shortest distance between the vertical line passing through the center of the cross section of the recess and perpendicular to the mold surface and the deep part of the side end line of the cross section of the recess is larger than the shortest distance to the shallow part on the same vertical surface. The permanent formwork according to claim 1 or 2 having the following shape.