JPS63179732A - Concrete molded form and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a concrete molded body in which frost damage, salt damage, chemical deterioration, carbonation, etc. are suppressed, and a method for producing the same.

[Conventional technology]

Concrete molded bodies are known as highly durable materials, but recently there has been a strong demand for improved durability against freezing damage, salt damage, chemical deterioration, carbonation, etc. in offshore development, nuclear facilities, cold regions, etc. There is.

Countermeasures for these include making the concrete itself highly watertight, laminating sheet materials such as synthetic resin or rubber on the surface of the hardened concrete molding, and applying paints such as epoxy resin or asphalt. Corrosion-resistant coatings such as coatings are applied. In this conventional method, the adhesion between the coating material and the concrete is inhibited by excess water in the early stage of concrete hardening, water absorbed from rain, etc., and free lime and impurities that float during the hardening process, resulting in large concrete molded bodies. For special structures with complicated shapes, it is difficult to deal with peeling and lifting of coating materials.

[Problems to be solved by the present invention]

However, since corrosion-resistant coating materials such as synthetic resins, rubber, and asphalt have high water-impermeability and almost no air permeability, uncured mortar and concrete covered with coating materials are slow to dry due to extremely slow drying of moisture. However, it had the disadvantage of requiring a long time and prolonging the process.

Furthermore, moisture remaining in hardened concrete and mortar repeatedly expands, contracts, and generates water vapor due to changes in ambient temperature, causing peeling of the coating layer and poor adhesion of the coating layer. The coating layer tends to peel off due to the embossment of free lime and impurities that occur during the hardening process of concrete and mortar.

For these reasons, concrete coating treatment is carried out only on essential parts, and there is a major problem in that the coating layer must be periodically repaired to prevent lifting or peeling.

[Means for solving problems]

That is, the present invention is a concrete molded body characterized by having an air permeable resin film as an outer skin layer through a fiber layer, and a breathable resin film integrally formed as an outer skin layer of the concrete molded body through a fiber layer. The present invention provides a method for producing a concrete molded body, which is characterized by providing a resin film.

The breathable resin membrane used in the present invention has recently been developed for use as a main material in cutting-edge technology such as lithium batteries, uranium 67 fluoride separation membranes, gas separation membranes, and reverse osmosis membranes, or as a main material for water-repellent products such as diapers. Resin membranes are attracting attention as materials that do not leak or get stuffy.These breathable resin membranes are known to be made of polyolefins such as polyethylene, polypropylene, polyproethylene, polyamide, polyurethane, etc.The water-blocking properties of these membranes are Normally, water pressure resistant (J Engineering S L-
1092, A method, static soil properties) 500smH, 0 or more. In addition, breathability is moisture permeability ABTM E 96-6
Normally 100-10000 f/y/, ATM, 24 hr. Like general resin films, this breathable resin film has poor adhesion to cement-based hydraulic materials such as concrete and mortar, and is extremely thin, so it cannot be used with large particles such as gravel or sand when using concrete or mortar. In a state where aggregate is mixed, it is difficult to completely adhere to the breathable resin film having a smooth surface, and there is a drawback that it is easily damaged.

In the present invention, in order to further enhance the effect, it is preferable that the fiber layer is integrally formed on both the front and back surfaces of the breathable resin film by dotting, and more preferably within a range that does not impair the air permeability of the breathable resin film. It is desirable that the entire surface be bonded to the surface. The fibers on both the front and back sides may be of the same quality or of different types; for example, the side in contact with the concrete layer is made of coarse nonwoven fabric, and the surface side is made of a nonwoven fabric with a rough texture, taking into consideration the adhesion of concrete. A woven fabric such as plain weave may also be used in consideration of this.

The fiber layer used in the present invention is made of resin such as polyester or polyamide, polyacrylic, polyethylene, polypropylene, ethylene vinyl acetate copolymer, metal such as iron, aluminum, copper, or oxide such as alumina or silica. , woven fabrics or non-woven fabrics made of inorganic fibers such as glass or carbon fibers, or single or blended fabrics of knitted or woven fabrics are used.

The thickness and shape of the fiber layers on both the front and back sides are selected depending on the fluidity and moisture content of the concrete being poured, but if the fiber layer used on the back side is too thick and too fine, it will function as a filter for the concrete and the fibers will Since sufficient interlocking of concrete cannot be obtained, the fiber layer used in the present invention is preferably thin and coarse in order to reinforce the breathable resin film and maintain the air permeability of the film.

The fibrous layer is thermally welded or bonded in advance while being partially embedded in the breathable resin film, and it is necessary to ensure that the air permeability of this membrane removal is not impeded.

In addition, by interposing one of the fiber layers on both the front and back surfaces between the breathable resin membrane and the concrete, the concrete penetrates into the fiber layer and good adhesion is not only obtained, but also the surface The presence of the fiber layer prevents the membrane from tearing due to impact during concrete pouring, vibration or centrifugal force during the molding process, or absorbs the difference in linear expansion coefficient between the concrete cured material and the membrane that occurs after concrete hardens. Effects are also given.

In addition, in the case of uncured concrete covered with a breathable resin film made by laminating a fiber layer, a moderate amount of water is released into the atmosphere through the film, so the effect on the curing time is extremely small, and the concrete hardens. The curing period is rarely extended. Furthermore, since the release of water is determined by the moisture permeability of the membrane, the dry-out phenomenon of concrete can also be prevented.

Furthermore, moisture from rain or underground water is blocked by the surface film, so it is not absorbed by the concrete, and the concrete hardens and dries without interruption.

The concrete molded body provided with the outer skin layer in which the fiber layer and the breathable resin membrane of the present invention are integrally formed can be used for bridge piers, utility poles, railway sleepers, humid pipes, etc., and has durability, weather resistance, chemical resistance, etc. It can be applied to protect the surface of all concrete molded bodies that require In the case of pipes, when applying to the inner circumferential surface of the pipe, once the centrifugal forming is completed, the outer skin of the present invention is immediately attached to the inner circumferential surface and the formwork is rotated again to form concrete. can be closely integrated with.

Examples of concrete molded bodies according to the present invention are shown in the accompanying drawings. Figure 1 shows a cross-sectional view of a concrete well used as a bridge pier, in which an outer skin layer A is provided on the outer peripheral surface of a concrete pipe (4). It is being (1) shows the breathable resin film, (2) shows the fiber layer on the surface side, and (3)
indicates the fiber layer on the back side. If this well is used as a bridge pier, it will prevent the concrete from deteriorating due to seawater, improving durability and weather resistance.

In addition, Figure 2 shows concrete sleepers.A
is an outer skin layer provided on the entire surface, (1) is an air-permeable resin film, (2) is a fiber layer on the front side, and (3) is a fiber layer on the back side. ) are closely attached to the concrete (4) through the fiber layer, and sleepers coated with the skin A in this way can be used in cold regions or on coastlines to prevent concrete damage due to frost damage or salt damage. It can prevent deterioration and improve durability and weather resistance. Figure 3 shows
Concrete pipe (4) showing a cross-sectional view of a humid pipe
A film A is provided on the inner circumferential surface of the film, and (1) is an air-permeable resin film, and (2) and (3) are fiber layers.

The fibrous layer (3) on the back side of this one is tightly attached to the concrete surface by centrifugal force, and the inner surface of the pipe is covered with a breathable resin film reinforced by the fibrous layer (2). It is possible to prevent deterioration of concrete due to organic substances and chemicals contained in concrete, and has the effect of improving durability. FIG. 4 shows an enlarged sectional view of the outer skin sheet A.

[Function] In the outer skin layer A used in the present invention, in which the fiber layers on both the front and back sides and the breathable resin film are integrally molded, the fiber layer (3) on the back side strengthens the adhesion with the concrete molded body, and The breathable resin film reinforced on both sides has a water-blocking property against liquids, such as water, but has a moisture-permeable effect against gases, that is, water vapor.

〔Example〕

The present invention will be explained below with reference to Examples.

Example 1 A cylindrical formwork with an inner diameter of 75 mm and a depth of 150 m was made with a polypropylene non-woven fabric (60~0.35+ ma) heat-welded on the inner surface and a polyvinyl chloride woven fabric on the surface to form a vent with a thickness of 50 μm. polyethylene film (moisture permeability 16
00~. 11t0.24h4, water pressure resistance 2000■H, 0
After setting the cement mortar (s/6-3,
Hip = 60%, cement: Portland cement, sand: silica sand No. 4) was poured.

After curing indoors for 24 hours, the chickens were raised, and the bottom and top of the film were coated with asphalt to obtain test specimens. This was left indoors and weight changes were measured over time.

Comparative Example 1 An example in which the fiber layer and the breathable resin film are integrally formed without an outer skin.

Comparative Example 2 In place of the breathable polyethylene film in Example 1, a non-breathable polyethylene film with a thickness of 50 μm (moisture permeability 89 inches, l atm, 24 hr) was used.
A test specimen was obtained using the following, and the same test as in Example 1 was conducted. The weight change over time is shown graphically in FIG. 4, and other results are shown in Table 1.

Example 2 In Example 1, instead of using the polypropylene nonwoven fabric on the back side, a polyester nonwoven fabric (with a thickness of 60 to about 1
A test specimen was obtained using the following test sample, and the same test as in Example 1 was conducted. The weight change over time is t! compared to Example 1! It was the same. Other results are shown in Table 1.

Comparative Example 3 In Example 1, a test piece was obtained without using any nonwoven fabric, and the same test as in Example 1 was conducted. Other results are shown in Table 1, and the water-blocking properties were good, but the adhesive strength was poor.

Table 1 Hata A double-sided tape of 3 iy x 3 cwt was pasted on the surface of the test piece, a clamp of the same size was attached thereto, and the tensile strength was calculated from the tensile fracture strength when pulled in the vertical direction at 1QQ5420°C.

[Effects of the present invention]

The concrete molded body of the present invention is reinforced with a fibrous layer on the surface through a fiber layer as an outer skin layer, and is coated with a breathable resin film, so it prevents deterioration of concrete due to frost damage, salt damage, chemicals, etc., and is durable. In addition to the effect of improving hardness and weather resistance, the resin film is also breathable, and since the resin film is integrated with the concrete via the fiber layer on the back side, it prevents peeling and lifting of the resin film. It produces special effects such as no generation and excellent adhesive durability.

In addition, in the installation of the concrete molded body of the present invention, excess moisture in the poured concrete is appropriately dissipated to the outside through the breathable resin membrane, so compared to the case of an impermeable resin membrane, It has very little effect on the hardening time of concrete, and has the effect of shortening the hardening and curing period of concrete.

Furthermore, since the amount of water dissipated from the concrete IJ-container is regulated by the breathable resin film, it is effective in preventing the dry-out phenomenon of concrete that is often observed when the concrete does not have a resin film.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a concrete well, FIG. 2 is a perspective view of a concrete sleeper, FIG. 3 is a sectional view of a humid pipe, and FIG. 4 is an enlarged sectional view of a skin sheet A. FIG. 5 is a diagram showing changes in weight over time in Examples and Comparative Examples. (1)...Breathable resin membrane (21, (3)...Fibre layer (4)...Concrete patent Applicant: Mitsui Toatsu Chemical Co., Ltd. and one other attorney: Miki Donaka Mura, patent attorney; Man-°"1 ・ 1 1,・'nee・ Figure 1 Figure 3 Figure 4 Figure 5 Number of days in a day □

Claims (2)

[Claims] (1) A concrete molded body characterized by having a breathable resin film integrally formed with fiber layers on both the front and back surfaces as an outer skin layer. (2) A concrete molded article characterized in that a sheet-like material integrally formed with a breathable resin film having fiber layers on both the front and back sides is laid on the inner surface of a concrete molding form, and then concrete is poured. manufacturing method.