JPH11198114A - Method for applying colored concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to easily manufacture a colored concrete structure with the same feeling as a natural stone material by forming a colored coat layer on the surface of a shuttering and casting concrete with the same color as the colored coat layer into the shuttering, when coloring the concrete to be molded using the shuttering. SOLUTION: A colored coat layer is formed in advance of a coating composition which is stable in an acidic and/or a neutral atmosphere and is dissolved in an alkaline atmosphere as a physical property, on the surface of a concrete shuttering. Then concrete with the same color as the colored coats layer is cast into the shuttering. Consequently, alkali which is a water-soluble substance contained in cement works to melt the colored coat later, so that a coloring component penetrates the surface of the uncured concrete. Thus the surface of the concrete structure is colored. Therefore, it is possible to obtain the colored concrete structure free from a change in the concrete surface even when the colored concrete is chipped or cracked as damage or the surface of the concrete is degraded due to its exposure for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying colored concrete using a formwork.

[0002]

2. Description of the Related Art Concrete moldings (hereinafter simply referred to as concrete) have been used in many buildings as structural materials having excellent strength and durability. However, since the appearance of concrete is gray, the concrete is gray. Due to incongruity with the surrounding environment, the demand for colored concrete as a landscape material has been increasing in recent years. Various types of concrete coloring materials are required, from relatively small ones such as color blocks and color flat plates to large-scale civil engineering works such as seawalls and dikes.

Conventionally, as a method of coloring concrete, a method using a color cement, a method using a coloring agent such as a pigment, a method using a colored aggregate, and the like are known.
As a method of coloring the surface of concrete, a method of applying various finish coating materials to the surface has also been used.

[0004]

However, in the method of coloring the concrete itself, although a uniform colored layer is obtained inside, the so-called efflorescence phenomenon occurs on the surface. There is a problem that the aesthetic appearance of the concrete surface is impaired because it differs depending on the type of aggregate, the amount of kneading water and the construction conditions. Further, as a material of the mold, there are wooden, metal, plastic, rubber and the like, but poor curing due to soluble alkali in the wood,
Due to metal rust stains, mold release failure from the mold, etc.
This impairs the appearance of the concrete surface and makes it difficult to reuse the formwork.

[0005] For this reason, the concrete surface after the mold release may be finished and surface-finished by sharpening, washing out, beating, sand plasting, etc., but such a surface treatment significantly increases the cost. It is inevitable to become. On the other hand, the method of painting the surface of concrete with paint is a method that has been practiced for a long time. Deterioration in weather resistance becomes a problem, and furthermore, if the coating layer on the surface is lacked due to some physical action for surface coating, there is a problem that the uncolored concrete surface layer is exposed and the appearance is impaired.

Accordingly, the performance of colored concrete is as follows:
Artificial structures such as buildings, roads, and bridges are required to be in harmony with the environment surrounding colored concrete, such as greenery, waterfronts, topography, and cities. Accordingly, an object of the present invention is to solve the problems of the prior art relating to colored concrete and to provide colored concrete close to natural stone efficiently and economically.

[0007]

The above object is achieved by the present invention described below. That is, in the present invention, in coloring concrete using a mold, a colored coating layer is previously formed on the surface of the mold, and concrete colored in the same color as the colored coating layer is cast on the mold. It is a colored concrete construction method characterized by performing.

[0008]

In the concrete mold forming method, when the concrete is poured into the mold, the surface of the mold is colored in advance so that it is stable in an acidic and / or neutral atmosphere and soluble in water in an alkaline atmosphere. Forming a coating film, placing concrete colored in the same color as the colored coating film layer in this mold, curing, and releasing the mold to give it a surface texture similar to that of natural stone. Concrete structures are easily provided.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. As the mold used in the present invention, any of wooden, metal, plastic, rubber and concrete molds can be used.

In the present invention, a colored coating layer is formed on a surface of the mold in advance by using a coating composition comprising a binder which is stable in an acidic and / or neutral atmosphere and has a property of dissolving in an alkaline atmosphere. When concrete colored in the same color as the colored coating layer is poured into the frame, the colored coating layer is dissolved by the alkali of the water-soluble substance in the cement, and the coloring component penetrates into the uncured concrete surface, In addition to coloring the surface layer of the concrete structure, it also prevents the formwork and the concrete from sticking to each other and improves the releasability after curing.

[0011] The binder used in the above coating composition is
It is sufficient that the coating film obtained thereby is stable in an acidic and / or neutral atmosphere and easily dissolved in water in an alkaline condition. Examples thereof include vinyl acetate, acrylic, urethane, and polyester. And water-soluble resins and mixed systems thereof.

By using colored concrete of the same color as the colored coating film as the concrete to be cast, the concrete surface may be damaged due to chipping or cracking of the colored concrete, or deterioration of the surface due to long-term exposure. It is possible to obtain a colored concrete structure with no change.

As the coloring material, any of pigments, dyes and the like can be used. However, coloring materials having alkali resistance and good affinity with cement are suitable, and general inorganic pigments and organic dyes can be used. In addition to dyes and pigments, special functional powders such as fluorescent pigments and infrared absorbing pigments, and particle diameters of 0.5 to 3 such as colored silica sand
It is also possible to change the function and finish of the concrete surface using aggregates of about mm.

[0014]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the description, parts or% are based on weight. Example 1 Brown concrete [Painting composition 1] Pigment (Bengara, iron black) 8 parts Binder (vinyl acetate emulsion) 60 parts Water 32 parts

The paint of Formulation 1 was applied to the surface of a synthetic resin mold by spraying to a coating thickness of 50 μm and air-dried for 12 to 24 hours. [Concrete mix 1] Portland cement 20 parts Pigment (Bengara, iron black) 2 parts Aggregate 60 parts Water 18 parts The above-mentioned concrete mix 1 is poured into a synthetic resin form having the colored coating film formed thereon. After curing for 3 days, when the mold was removed, both the surface and the inside were colored brown.

Comparative Example 1 Concrete composition 1 was poured into a synthetic resin form without a coating layer, and after curing for 3 days, the form was removed.
Although the inside was colored brown, the surface was whitish and uneven. In addition, a part of the concrete adhered to the mold at the time of release from the mold, the surface of the concrete became rough, and the mold could not be reused.

Example 2 Green Concrete [Painting Formula 2] Pigment (Dipoxide Color Green # 9310) 20 parts Binder (acrylic water-soluble resin) 50 parts Water 30 parts The coating material of Formulation 2 was coated on the surface of a metal mold. Was applied to a thickness of 30 μm by spraying and air-dried for 12 to 24 hours.

[Concrete Mix 2] Portland cement 20 parts Pigment (Dipoxide Color Green # 9310) 4 parts Aggregate 60 parts Water 16 parts Concrete mix 2 is cast on a metal mold on which the colored coating film is formed. After curing for 3 days, the mold was removed and the surface and inside were colored green.

COMPARATIVE EXAMPLE 2 In the paint formulation 2 of Example 2, a paint using an acrylic emulsion resin which forms a stable film in an alkaline atmosphere as a binder is applied to the surface of a metal mold by spraying. Apply 30 μm and air dry for 12-24 hours. Concrete mixture 2 was poured into the mixture, and after curing for 3 days, the mold was removed. As a result, the coating film adhered to the mold, and the concrete surface was not colored.

Comparative Example 3 A commercially available green exterior cement-based spraying material was sprayed on the surface of uncolored concrete to produce a colored concrete. When each of the concrete structures of Example 2 and Comparative Example 3 was exposed outdoors for one year, the appearance of the concrete structure of Example 2 hardly changed, whereas the concrete structure of Comparative Example 3 was changed. The surface was remarkably changed, and the surface texture was inferior.

[0021]

According to the present invention, the colored coating film formed on the mold surface is essentially completely dissolved by the alkaline substance in the concrete milk. By forming a "mixed concrete layer", not only is the strength significantly improved compared to a normal concrete surface, but it is also possible to suppress the occurrence of efflorescence due to exposure. Since the coating film does not dissolve in an acidic and / or neutral atmosphere, the coating film applied to the mold is not washed away due to rainfall during construction outdoors.

Claims (2)

[Claims] 1. In coloring concrete using a mold, a colored coating layer is previously formed on the surface of the mold, and concrete colored in the same color as the colored coating layer is cast on the mold. A colored concrete construction method, characterized in that: 2. The colored concrete application method according to claim 1, wherein a coating film having a property of being stable in an acidic and / or neutral atmosphere and being soluble in an alkaline condition is used as the colored coating layer.