JPH0523561B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing concrete or mortar in which a corrosion-resistant coating layer is formed on the surface of the concrete or mortar. This invention relates to a method for producing concrete or mortar. (Prior art) Cement concrete and mortar are widely used as inexpensive building materials, but on the other hand, they cannot be used in chemical environments such as acids, salts, seawater, oil, and even carbon dioxide and sulfur dioxide gas. It has the disadvantage of being attacked. In order to compensate for this drawback, it has been conventional practice to coat the surface of concrete with a corrosion-resistant paint. These are called coatings or linings, but this distinction is usually made by 0.2
Coating when creating a thin coating film of ~0.3mm,
It seems that the process of creating a thick coating of 1mm or more is called lining, but the distinction is not always clear. Asphalt, tar, or thermosetting resin paints are generally used as coatings. The most important thing in corrosion-resistant coating of concrete structures is to coat the concrete so that no pinholes remain on the surface, but in practice this is not the case when applying paint to the surface of concrete after it has been formed. is not always easy. That is, since there are many large and small holes on the surface of concrete, it is extremely difficult to coat all the holes, including pinholes, with certainty. Therefore, in the past, the number of applications was increased,
Attempts have been made to solve this problem by performing primer treatment, but this requires considerable effort. For example, in the salt damage guidelines for road bridges (draft) and its commentary (published by the Japan Road Association in February 1980), concrete coatings to prevent salt damage are specified in accordance with the usage conditions of structural members. System A
It is classified into three types: species, B species, and C species. For any of these coating systems, primer treatment with an epoxy resin primer or polyurethane resin primer (first treatment), putty treatment with epoxy resin putty or vinyl ester resin putty (second treatment), epoxy resin paint, polyurethane resin or vinyl ester Intermediate coating with resin paint (third
It requires four steps: (4th treatment) and topcoating with polyurethane resin (4th treatment). Moreover, it is standard to leave an interval of 1 to 10 days between each process. In addition, in order to increase the adhesion between the paint film and concrete and fully demonstrate the corrosion-prevention effect, before painting, remove any harmful effects such as laitance on the concrete surface, formwork release agent, adhering salt, adhering oil and fat, moisture, etc. It is necessary to remove things that cause this. To prepare the surface, the company says it will clean and dry using sander wipes, thinner wipes, brushes, and air blowers. However, such processing is extremely time-consuming and costly. In addition, even after such treatment, there was a problem in that the resulting coating was likely to peel off. In addition to this, polymer-impregnated concrete and resin concrete are methods of imparting corrosion resistance to concrete, but these methods are expensive and unsuitable for general application. (Problems to be Solved by the Invention) This invention involves forming a corrosion-resistant coating on the inner surface of the formwork by applying a coating treatment in advance, and forming concrete or mortar using this formwork. At the same time as the subsequent demolding, a corrosion-resistant coating layer is applied to the surface of the mold, thereby easily producing concrete or mortar with good acid resistance. (Means for Solving the Problems) The first invention of the present application forms a peelable film directly on the inner surface of the mold without using a mold release agent, and on top of this film, asphalt-based, tar, etc. A corrosion-resistant coating is formed on the inner surface of the form by applying one or more types of paint selected from thermosetting resin-based paints or thermosetting resin-based paints, or resin mortar using thermosetting resin. Filling the inside with fluid concrete or mortar, removing the formwork after curing it, and simultaneously peeling off the corrosion-resistant coating along with the peelable coating from the formwork and inverting it onto the surface of the concrete or mortar molded body. It is characterized by: Further, in a second invention, a thermoplastic acrylic resin paint is applied on the peelable film in the first invention to form an acrylic resin film, and an asphalt-based, tar-based or A corrosion-resistant coating is formed on the inner surface of the form by applying one or more types of paint selected from thermosetting resin paints or resin mortar using thermosetting resin, and The feature is that fluid concrete or mortar is filled, the formwork is removed after curing, and at the same time, the corrosion-resistant coating is peeled off from the formwork together with the peelable coating, and the material is inverted onto the surface of the concrete or mortar molded body. That is. This invention will be further explained below. In this invention, first, a peelable paint is directly applied to the inner surface of the mold without applying a mold release agent to form a peelable coating thereon. The strippable paint used here is also known as strippable paint, and is conventionally used to form a continuous strippable film on the surface of the product by applying it to the surface of the product. It is something that Strippable paints are generally applied to the surface of finished products to temporarily protect them from damage or corrosion during transportation or storage, and are then removed after use. Ta. Although the peelable film formed by applying this paint has weak adhesion to the coated surface of the product, it has good continuity as a film, and although it is relatively soft, it is strong and cannot be peeled off. It is possible. In this invention, such a peelable paint is applied to the inner surface of the mold to form a peelable coating thereon. A peelable paint will harden considerably in about one hour after application, depending on the type, but it is preferable to leave it for about two to four hours in order to increase the strength of the coating. The main components of the peelable paint used here are resins such as polyvinyl chloride, polyvinyl-vinyl acetate copolymer, polyvinyl butyral, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and acrylic. These peelable paints are applied to the inner surface of the formwork by spraying, brushing, etc., and then hardened to form a peelable coating thereon. Next, one or more paints selected from rubber asphalt, asphalt epoxy, tar, tar epoxy, or thermosetting resin paints, or resin mortar is applied on top of this to provide corrosion resistance. Form a coating layer. The thermosetting resin used here is selected from unsaturated polyester resins, epoxy resins, furan resins, phenol resins, polyurethane resins, and acrylic resins. Note that there are two types of acrylic resin paints: thermoplastic and thermosetting, and thermosetting acrylic resin paint can be used here. These resins have high watertightness, abrasion resistance, and chemical resistance, as well as high tensile strength and elongation, and are suitable for such uses. These paints can be coated or lined onto the peelable film by applying them onto the peelable film using a trowel, roller, brush, or the like. In addition, the second invention does not form a corrosion-resistant coating layer directly on a peelable coating, but in addition to forming a peelable coating, it also uses heat-resistant acrylic resin, which is a resin with good weather resistance. A plastic acrylic resin paint is applied to form a coating layer, and one or more types selected from asphalt-based, tar-based, or thermosetting resin paints similar to those used in the first invention are applied thereon. Paint or resin mortar using thermosetting resin is applied. In the present invention, the coating formed on the formwork is then reversely coated with concrete or mortar when the mold is removed, and therefore the adhesive strength of each coating to the adjacent surface is stronger the closer it is to the concrete or mortar to be formed. must be selected so that In other words, it is bonded to concrete or mortar to be placed, maximizing the adhesive strength of the coating,
Thereafter, the adhesive strength between each coating is gradually reduced when viewed from the concrete or mortar side, and the minimum adhesive strength is the adhesive strength between the peelable coating and the formwork. No mold release agent is used between the formwork and the peelable coating. This makes it possible to keep the surface of the coating reversed by demolding beautiful. The formwork with the above-mentioned corrosion-resistant coating layer formed on the peelable coating is then assembled, filled with fluid concrete or mortar in a conventional manner, and cured. Filling with concrete or mortar is preferably carried out while the thermosetting resin applied to the inner surface of the form is semi-hardened. Although this depends on the type of resin, it is usually 1 to 3 hours after the paint or resin mortar is applied to the formwork.
As a result, the peelable coating is directly bonded to the corrosion-resistant coating layer with or without the acrylic resin coating, and the corrosion-resistant coating layer is also bonded to concrete or mortar. In the end, the peelable coating, the corrosion-resistant coating layer, and the concrete or mortar are
Alternatively, the peelable coating, the acrylic resin coating, the corrosion-resistant coating layer, and concrete or mortar are bonded together. Concrete or mortar is cured under these conditions. Once curing is complete, remove the formwork. Then, the peelable coating and the corrosion-resistant coating layer, which had been previously formed on the inner surface of the formwork, peel off from the formwork side with or without the acrylic resin coating layer sandwiched between them and turn over to the concrete or mortar side.
As a result, the concrete or mortar surface
The material is coated with a corrosion-resistant coating layer and a peelable coating layer, with or without an intervening acrylic resin coating layer, and at that moment, corrosion-resistant concrete or mortar is completed. The coating layer formed on the surface of the corrosion-resistant concrete or mortar produced according to the present invention is of good quality, and has a very beautiful appearance with no pinholes on the surface. Also,
In the second invention, since there is an acrylic resin coating layer under the peelable coating, this product has particularly excellent weather resistance. This invention will be further explained below by giving experimental examples. (Experiment example) In this experiment, the peelable paint used was Boncoat ST-372 (manufactured by Dainippon Ink & Chemicals, Inc., trade name), whose main component was acrylic, and the resin used was epoxy resin, whose main component was epoxy resin. Unitack #5000-3
(manufactured by Onoda Co., Ltd., trade name) (hereinafter simply referred to as "epoxy resin") was used. Mortar chloride ion permeability test The test was carried out by sandwiching two disk-shaped specimens of 50 mm (diameter) x 5 mm (thickness) between cell containers, placing a 10% NaCl aqueous solution in one of the containers, and testing the chlorine ion permeability with an ion meter. The amount of ion permeation was measured and the diffusion coefficient was calculated. The specimen was created as follows. The formwork was prepared by preparing a vinyl chloride cylinder with an inner diameter of 50 mm and a depth of 5 mm, and applying grease to the edges (rim thickness: 5 mm) and placing it on a glass plate to make it stick. . The mortar has a water-cement ratio of 54.8% and a cement-to-fine aggregate ratio of 1:2.
And so. In addition, fine aggregate with a maximum dimension of 2.5 mm was used. Among these mortars, the one with no treatment on its surface is the basic specimen (hereinafter referred to as "untreated"), and the one with only a peelable coating on the surface of the basic mortar in contact with the glass (hereinafter referred to as "untreated") is the basic specimen. (referred to as “capsular inversion”),
In addition, a 1 mm thick coating of mortar containing a peelable coating and a polymer dispersion having the composition shown in Table 1 is inverted on the surface of the basic mortar (hereinafter referred to as "mortar inversion"); Mortar with a peelable coating according to the present invention and a corrosion-resistant coating layer of 0.5 mm thick epoxy resin formed on the surface of the mortar (hereinafter referred to as "resin inversion"),
Furthermore, the surface of the basic mortar was coated with epoxy resin after curing (hereinafter referred to as "resin post-coating") at a temperature of 20℃ and humidity until 7 days after the material was aged.
Cured in a 90% constant temperature room. The test results were as shown in Table 2. As shown in the same table, the diffusion coefficients for coating inversion, mortar inversion, and resin inversion are extremely small values compared to those without treatment, but the resin post-coating does not completely close the pinholes. This is a relatively large value.

【table】

[Table] Freeze-thaw test for concrete Concrete specimens measuring 10 x 10 x 40 cm were prepared using the composition shown in Table 3.

[Table] A freeze-thaw test of this concrete was conducted according to the JIS draft, and the weight loss rate and relative dynamic elastic modulus were measured. The test specimens are basically those with no surface treatment, which is referred to as "untreated", and the basic concrete with a peelable coating and a polymer dispersion of the composition shown in Table 1 with a thickness of 2~ A 3 mm mortar coating is inverted (hereinafter referred to as "mortar inversion"), and a peelable coating and an epoxy resin coating layer according to the present invention are inverted on the basic concrete surface (hereinafter referred to as "resin inversion"). ), the basic concrete was post-coated with epoxy resin after curing (hereinafter referred to as ``resin post-coating''). The specimen is material code 7.
The molds were cured in a thermostatic room at a temperature of 20°C and a humidity of 90% until the end of the day. In addition, in the case of mortar inversion and resin inversion, the concrete pouring surface should be coated with mortar or epoxy resin containing polymer dispersion on the day after the concrete is poured, and then a peelable paint should be brushed on top of this. It was applied to the same condition as the surface in contact with the formwork. In addition, for resin post-coating, the mold was removed after 6 days of age, and epoxy resin was applied to the surface. The amount of epoxy resin used for resin reversal and resin post-coating was equal to 110 g per specimen. As for the test results, Table 4 shows the change in weight loss rate over time, and Table 5 shows the change in relative dynamic elastic modulus over time.

【table】

[Table] Concrete chemical resistance test In this test, a 10 x 10 x 40 cm concrete specimen was immersed in a 5% solution of hydrochloric acid (JSK8181 reagent special grade) and the weight loss rate was measured. The tests were carried out using concrete with the composition shown in Table 3 in four cases: no treatment, mortar reversal, resin reversal, and resin post-coating. The methods for curing the concrete and post-coating with resin were the same as in the freeze-thaw test for concrete described above. The test results are shown in Table 6 as the weight reduction rate of concrete.

[Table] Example 1 A reinforced concrete U-type 240 was manufactured using a U-shaped steel formwork as follows. First, the formwork release material on the formwork surface was wiped off, and then a peelable paint was brushed on. Boncoat ST-372 was used as the peelable paint and was applied uniformly with a brush at a rate of 50 c.c./m ² . This application is done in two coats.
A second coat was applied 3 hours after the first coat. After the peelable film is formed, 1 part of Unitac #5000-3 and 1 part of dry sand are applied as epoxy resin.
A resin mortar mixed at a ratio of 0.7 was applied to a thickness of 2 mm using a brush. After that, the formwork was assembled, resin mortar was applied, and two hours later, the water-cement ratio was 35.5.
%, unit cement amount 450Kg/m ³ , and fluidized concrete with a slump of 20cm was poured. When the formwork was removed the next day, the coating and resin mortar were reversed onto the surface of the concrete, and a corrosion-resistant coating layer was formed on the entire surface of the concrete that was in contact with the formwork.
Moreover, the surface was a continuous peelable film and had a glossy appearance, and no pinholes were observed on the surface. Example 2 In the wall-column steel formwork shown in the figure, after assembling the steel panel A corresponding to the inner wall, 100 parts of peelable paint (trade name: Strip Paint, Kansai Paint Co., Ltd.) was applied to the inner surface. A mixture of 60 parts of thinner and 3 parts of chromium oxide was thoroughly stirred and then sprayed at a rate of 200 g/m ² using an airless type spraying device, and the peelable coating paint was dried for about 1 hour.
Acrylic resin paint was sprayed on top of it as follows. First, Topcoat type 3 (thermoplastic type) and Type 4 (thermosetting type) manufactured by Onoda Co., Ltd. were used as acrylic resins, and the same amount of thinner was added to each type and stirred. The formwork was divided into three sections in advance, two sections were sprayed with Top Coat Type 3 and Top Coat Type 4 separately, and the remaining one section was left untreated. After 3 hours, a mixture of 100 parts of the main material of epoxy resin (trade name: Onoda Co., Ltd., Unitac #5000-3) and 50 parts of a hardening agent was added on top of the mixture.
It was sprayed at a rate of 800 g/m ² . The subsequent process involves setting reinforcing bars in the predetermined positions in this formwork, then erecting steel formwork B, which corresponds to the outer wall treated in the same manner as steel panel A, and finally installing spacers. The entire formwork was tightened to complete setting the formwork. Concrete was poured from the top of the formwork and compacted using a rod vibrator. The formwork was removed after 7 days, and in all sections, the formwork was easily removed from the interface with the peelable coating and turned over to the concrete side, but there was no damage to the coating, and the coating remained intact. The reversal was extremely good. As a weather resistance test of this resin-coated concrete, 30 x 60 x 12
(cm) in size, a stand was built on the roof of a building facing the sea in Kamakura City, Kanagawa Prefecture, and two pieces of each were exposed outdoors. The remaining one was used as a non-exposed specimen for comparison with the exposed specimen. After three months had elapsed, the condition of the peelable coating on the surface was that in the case of only the epoxy resin and the peelable coating, the surface had lost its luster and peeled off significantly. The product with Topcoat type 3 sandwiched between them showed some yellowing compared to the unexposed product, but was in good condition with no blistering or peeling. Furthermore, the specimens using Topcoat Type 4 showed almost no change in gloss or color. It was perfect with no blisters or peeling. (Effects of the Invention) According to the present invention, a continuous corrosion-resistant coating is formed on the surface of the concrete that was in contact with the formwork at the same time as the formwork is removed, and furthermore, the coating has no pinholes. Since it is beautiful and has strong adhesive strength, concrete or mortar with excellent corrosion resistance and appearance can be easily obtained, and it is thought that this method will be widely used in place of the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the steel formwork of the wall column. A, B...panel.

Claims (1)

[Claims] 1. A peelable film is formed directly on the inner surface of the mold without using a mold release agent, and on top of this film, an asphalt-based, tar-based, or thermosetting resin-based paint is further applied. Apply one or more types of paint or resin mortar using thermosetting resin to form a corrosion-resistant coating on the inner surface of the form, and fill the form with fluid concrete or mortar,
Corrosion-resistant concrete or mortar molding characterized by removing the formwork after curing, peeling off the corrosion-resistant coating together with the peelable coating from the formwork and inverting it to the surface of the concrete or mortar molding. How the body is manufactured. 2 Form a peelable film directly on the inner surface of the mold without using a mold release agent, and apply a thermoplastic acrylic resin paint on top of it to form an acrylic resin film,
On top of this film, one or more paints selected from asphalt-based, tar-based, or thermosetting resin paints, or a resin mortar using thermosetting resin is applied to the inner surface of the formwork. A corrosion-resistant coating is formed, the formwork is filled with fluid concrete or mortar, and after curing, the formwork is removed, and at the same time, the corrosion-resistant coating is peeled off from the formwork together with the peelable coating to form concrete. Or, a method for producing a corrosion-resistant concrete or mortar molded body, which comprises inverting it onto the surface of the mortar molded body.