JPH07247187A - Production of colored cement-concrete product - Google Patents

Abstract

PURPOSE:To obtain a colored concrete product having a strong colored coating mainly containing a metal sulfate and stable in color tone in high efficiency by applying an aqueous solution of the metal sulfate on the surface of a concrete article and subjecting to steam aging. CONSTITUTION:An aqueous solution of a metal sulfate is impregnated into and/or applied on the surface of a cement-concrete article. The metal sulfate can be selected from copper sulfate, chromium sulfate, manganese sulfate, iron sulfate, etc. Subsequently, the treated cement-concrete article is subjected to steam aging to obtain a colored concrete product having a colored coating mainly containing the metal sulfate and/or its reaction product on the surface of the cement-concrete article. Further, the coloring is promoted and the colored coating is formed in an early stage by treating the surface of the cement- concrete article with an activating agent, e.g. an alkali aqueous solution (e.g. an aqueous solution of sodium hydroxide) or an aqueous solution of an oxidizing agent (e.g. an aqueous solution of hydrogen peroxide) before or after the impregnation and/or the coating of the metal sulfate aqueous solution.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a colored cement concrete product using a metal sulfate. More specifically, the present invention is a cement mortar, concrete panel, block, pile, tile, artificial stone,
The surface of mortar and / or concrete products such as tank towers is chemically treated to accelerate color development, the generated colored film (layer) does not peel off, and it has excellent long-term weather resistance and stability. And a method for easily and efficiently producing colored cement concrete products.

[0002]

2. Description of the Related Art Cement concrete products are used in large amounts in the fields of construction and civil engineering, but in recent years, due to harmony with nature and growing interest in the landscape, environmentally friendly colored cement concrete products. Has become strongly desired.

Conventionally, as a method for producing a colored cement concrete product, a pigment is mixed with a raw material such as cement at the time of producing the product, and a paint of a predetermined color or an emulsion of the pigment is brushed on the surface of the product. A method of applying by applying or spraying is known. However, the method of mixing with the above-mentioned raw materials not only requires a large amount of pigment, but also has a drawback that the coloring effect cannot be obtained unless expensive white cement is used, and it is difficult to produce a natural hue. Further, in the case of applying the coating material, peeling of the coating film easily occurs, weather resistance is inferior, etc., and since a large amount of organic solvent is used, there is a problem in handling and safety and hygiene. Is difficult to produce a natural color.

In addition to the method described above, JP-A-4
Japanese Unexamined Patent Publication No. 8-68620 proposes a method of coloring and coloring a cement product by applying an aqueous solution of a metal sulfate such as manganese sulfate and iron sulfate. Since this method uses a chemical reaction, the drawbacks of the method can be improved, but it takes a long time for the color tone to stabilize due to changes in color over time, In particular, a cement concrete product which has passed a long time after the production does not develop color, or the color development is insufficient and thus cannot be colored, and there is room for improvement in this method.

According to the research conducted by the present inventors, the details of the coloring and coloring mechanism of the method using the metal sulfate are not clear, but free Ca produced by the hydration reaction of cement in the cement concrete product is not clear. (OH) ₂ reacts with a metal sulfate to form fine crystals of a metal hydroxide and develops color,
Along with calcium sulfate and other reaction products that are produced at the same time, they enter into the minute gaps of the cement concrete in the surface layer of the cement concrete product to densify the surface layer, and the surface of the cement concrete is peculiar to the salt of microcrystalline hydroxide. It is presumed that a colored film layer is formed and colored. In addition, it is presumed that, in the hydroxide of microcrystals, the hydroxyl group is bonded to or substituted with oxygen in air or water and a part of the hydroxide becomes microcrystals of the oxide and is mixed in the surface layer. Also, it takes a long time for the color tone to stabilize. The leaching rate of free Ca (OH) ₂ bleeding from the cement concrete product to the surface layer, the rate of hydroxide formation reaction, the rate of oxide formation. For example, the cement concrete products that have passed a long time after production have a neutralized surface or are too dry. It is presumed that the decrease in color causes no color development or defective color development.

[0006]

In view of the above-mentioned points, the present inventors have aimed to develop a method for producing a colored cement concrete product capable of improving the above-mentioned problems.
Further, intensive studies were conducted for the purpose of improving the poor color development and instability of color tone in the method using the metal sulfate. As a result, when the surface of the cement concrete product is impregnated and / or coated with an aqueous solution of a metal sulfate and then steam-cured, color development is promoted, and the formation of a strong colored film (layer) is promoted at an early stage to obtain a stable color tone. It is possible to form a colored film (layer), the film does not peel off, and it is possible to easily and efficiently produce a colored cement concrete product with excellent long-term weather resistance and stability. Even if cement concrete products that have passed a long period of time and cannot be colored or are poorly colored due to neutralization, drying, etc., they can be colored well, and even the whitening phenomenon of cement concrete products It can be prevented and the above object can be achieved, and the surface of the cement concrete product is treated with an activator before or after the impregnation and / or application of the metal sulfate aqueous solution. And finding the like can be effectively colored, it was led to the present invention.

[0007]

The present invention is directed to the production of a colored cement concrete product in which a colored film containing a metal sulfate and / or a reaction product thereof as a main component is formed on the surface of the cement concrete product. The present invention relates to a method for producing a colored cement concrete product, characterized in that the surface of the cement concrete product is impregnated and / or coated with an aqueous solution of a metal sulfate and then steam-cured. Further, the present invention is
In a method for producing a colored cement concrete product, which comprises forming a colored film containing a metal sulfate and / or a reaction product thereof as a main component on the surface of the cement concrete product, the metal sulfate is formed on the surface of the cement concrete product. The present invention relates to a method for producing a colored cement concrete product, which comprises treating the surface with an activator before or after impregnating and / or applying an aqueous solution of a salt, followed by steam curing. Furthermore, the present invention is
In a method for producing a colored cement concrete product, which comprises forming a colored film containing a metal sulfate and / or a reaction product thereof as a main component on the surface of the cement concrete product, the metal sulfate is formed on the surface of the cement concrete product. The present invention relates to a method for producing a colored cement concrete product, which comprises treating the surface with an aqueous alkali solution or an aqueous oxidizer solution before or after impregnating and / or applying an aqueous salt solution, followed by steam curing.

The cement concrete product to which the present invention can be applied is not particularly limited in kind, shape, size, etc., and examples thereof include cement mortar, concrete panel,
It can be applied to any cement mortar product and cement concrete product including blocks, piles, tiles, artificial stones, tank towers and the like.

In the present invention, the metal sulfate is a water-soluble metal sulfate, preferably 1B group, 6B group of the periodic table.
Water soluble metal sulphates selected from the group consisting of Group 7, Group 7B and Group 8 are used. Specific examples of the metal sulfates include water-soluble metal sulfates such as copper sulfate, chromium sulfate, manganese sulfate, iron sulfate, cobalt sulfate and nickel sulfate. The metal sulfates may be used alone or in combination of two or more.

The metal sulfate is impregnated and / or applied as an aqueous solution to the surface of the cement concrete product. When impregnated and / or applied, a color is developed to form a colored film on the surface of the cement concrete product. The method of impregnation and / or coating is not particularly limited, but a method such as brush coating, spraying, dipping or the like is usually adopted. The operation of impregnation and / or coating may be performed once or repeatedly. Further, the kind of metal sulfate may be partially changed and impregnated and / or applied. Various colored patterns can be formed by these operations.

The concentration of the metal sulfate aqueous solution varies depending on the amount of the metal sulfate impregnated in the cement concrete product and the coating amount, but is in the range of 2% by weight (anhydrous basis) to the saturation concentration or less, preferably 5%. It is appropriately selected and used from the range of 30% by weight in consideration of color tone. Generally, the lower the density, the darker the color tone becomes, and the darker the color tone becomes.
If it is less than wt%, it is hardly colored. In addition, the amount of metal sulfate impregnated into the cement concrete product and the amount applied vary depending on the surface condition of the cement concrete product, the type of metal sulfate, the concentration of the metal sulfate aqueous solution, etc. 1 to 150 g per 1 m ^{2 of} product surface area,
20 to 100 g is preferable. If the amount of impregnation or coating is too small, coloring is not sufficient, and if it is excessively increased, there is no particular change in color tone.

Further, in the present invention, a cement concrete
It is presumed that the whitening phenomenon of the product can also be suppressed because the alkali content in the product is prevented from being eluted from the inside to the surface by the densified surface layer and the colored film.

In the present invention, when the surface of the cement concrete product is treated with an activator before or after the impregnation and / or application of the aqueous solution of metal sulfate, color development is further promoted and the surface is neutralized. The effect of color development can be further enhanced even for a cement concrete product that is too dry, and a strong colored film with a stable color tone can be generated earlier. The treatment with the activator
It may be either before or after the impregnation and / or application of the metal sulfate aqueous solution, but before the impregnation and / or application, the absorption of the metal sulfate aqueous solution into the cement concrete product becomes less and the metal sulfate aqueous solution It is preferable because the amount to be impregnated and / or applied is small. As the activator, an alkaline aqueous solution and an oxidizing agent aqueous solution are preferably used.

As the alkaline aqueous solution of the activator, PH
Is an alkaline aqueous solution having a pH of 8 or more, preferably a pH of 10 or more. If the pH is too low, there is almost no color-promoting effect due to the alkali treatment. Therefore, it is preferable to use an alkaline aqueous solution having a high PH. As a treatment method, a method of impregnating and / or applying on the surface of a cement concrete product is adopted, and, for example, a method such as brush coating, spraying or depping is usually adopted. The operation of impregnation and / or coating may be performed once or repeatedly.

The amount of the impregnated and / or applied alkaline aqueous solution is
Although it varies depending on the surface condition of the cement concrete product, the pH of the alkaline aqueous solution, the viscosity, the drying speed, etc., ^{20 to} 2000 g, preferably 50 to 500 g is suitable per 1 m ^{2 of} the product surface area to be treated. If the impregnation and / or coating amount is too small, the effect of alkali treatment cannot be expected, and if it is too large, the metal sulfate component cannot penetrate into the cement concrete product, which is not preferable.

The alkaline substance used for preparing the alkaline aqueous solution may be any one that is water-soluble and has a pH of the aqueous solution of 8 or more, preferably 10 or more. Specific examples of the alkaline substance include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide, sodium bicarbonate (bi) carbonate, (bi) carbonates of alkali metals such as (bi) potassium carbonate, and sodium metasilicate. , Silicates of alkali metals such as potassium metasilicate, hydroxides of alkaline earth metals such as water glass, calcium hydroxide, magnesium hydroxide and strontium hydroxide, oxidation of alkaline earth metals such as calcium oxide and magnesium oxide The thing etc. can be mentioned. Moreover, these may be a mixture. Sludge and sludge water discharged from the cement concrete factory can also be used. Among the alkaline substances, calcium oxide, calcium hydroxide and the like are one of the components of the cement concrete product and are therefore particularly preferably used.

Further, as an aqueous solution of the oxidant of the activator,
A strongly oxidizing aqueous solution in which a solid or liquid oxidizing agent is dissolved in water is preferably used. Those having weak oxidizing power cannot be expected to have further effects by the activator. The treatment with the aqueous solution of the oxidizing agent is carried out by impregnating and / or applying it on the surface of the cement concrete product. It is usually carried out by a method such as brush coating, spraying or depping.
The operation of impregnation and / or coating may be performed once or repeatedly.

The impregnation and / or coating amount of the aqueous solution of the oxidizing agent is
Cement concrete - DOO product surface condition varies depending on the type and concentration of the oxidizing agent, processing product surface area 1 m ²
20 to 2000 g, preferably 50 to 500 g, is suitable. Further, those having a concentration of 0.5 to 30% by weight are preferably used. If the amount of impregnation and / or coating is too small, the effect cannot be expected, and if it is too large, the metal sulfate component cannot penetrate into the cement concrete product, which is not preferable.

Typical examples of the oxidizing agent include hydrogen peroxide, sodium nitrite, calcium peroxide, bleaching powder, and chlorates such as sodium chlorite, sodium hypochlorite and sodium chlorate. .

In the present invention, the cement concrete product impregnated and / or coated with the aqueous solution of metal sulfate is steam-cured. The steam curing may be performed any time after impregnating and / or applying the aqueous solution of metal sulfate, but it is preferable that the surface of the cement concrete product is in a wet state from the viewpoint of the coloring effect. The temperature of steam curing is 40-9.
The temperature is preferably 0 ° C, preferably 60 to 80 ° C, and the relative humidity is preferably in the range of 60 to 98% in order to form a stable colored film at an early stage. The steam curing time is usually 30 minutes to 24 hours, preferably 40 minutes to 4 hours, although it varies depending on the temperature, the curing atmosphere and the like.

[0021]

EFFECTS OF THE INVENTION According to the present invention, there is no color failure and color development is promoted, the formation of a strong colored film layer can be promoted at an early stage, and a colored film having a stable color tone can be formed. It is possible to easily and efficiently produce a colored cement concrete product which is excellent in long-term weather resistance and stability without being worn out, and also to prevent the whitening phenomenon of the cement concrete product.

[0022]

[Examples] In each example, the accelerated weathering test is conducted according to JIS
According to A1415 "Method of accelerated exposure test for plastic building materials", length 150 mm, width 70 mm, thickness 20
Using a 0 mm sample, the test was carried out under the conditions of a sunshine carbon, a black panel temperature of 63 ± 3 ° C., a humidity of 50% RH, and a spray cycle of 12 minutes in 60 minutes.

Example 1 In a 30 × 30 × 3 cm mold, ordinary Portland cement: sand = 1: 2 (weight ratio), water cement ratio (W / C) =
Pour 0.45 (weight ratio) of cement mortar, cure overnight in moist air, then demold, then overnight moist air, then 9
Cement panels were manufactured by performing air curing for 0 days. 80 g of a 15 wt% iron sulfate aqueous solution on a cement panel
/ M ² spray impregnation, wet panel 60 °
C, steam curing was performed for 1 hour at a relative humidity of 60%. The surface of the panel was colored at the same time as curing started to form a yellowish brown colored film, and a colored cement panel having a yellowish brown film equivalent to accelerated weathering 500 hours in 1 hour of curing was obtained. This colored cement panel maintained the yellowish brown color tone at the time of manufacture even if it was left outdoors for one year or more, and no change in color tone, fading, white flower phenomenon, etc. were observed.

Example 2 The cement panel produced in Example 1 was coated with 80 g / m ^{2 of an} aqueous sodium hydroxide solution of PH12 as an activator, and iron sulfate having a concentration of 15% by weight was applied while the panel surface was wet. The aqueous solution was impregnated by spraying at 80 g / m ² , and the wet panel was steam-cured at 60 ° C. and 60% relative humidity for 50 minutes. The surface of the cement panel develops color at the same time as it is impregnated with an aqueous solution of iron sulfate, and after 50 minutes of curing, accelerated weathering 500
A pigmented cement panel was obtained with a yellowish brown coating that was comparable in time. This colored cement panel maintained the yellowish brown color tone at the time of manufacture even if it was left outdoors for one year or more, and no change in color tone, fading, white flower phenomenon, etc. were observed.

Example 3 The coating and impregnation order of the sodium hydroxide aqueous solution and the iron sulfate aqueous solution of Example 2 was reversed, the iron sulfate aqueous solution was sprayed at 90 g / m ² and impregnated, and then the sodium hydroxide aqueous solution of PH 12 was added to 8 times.
Steam curing was performed in the same manner as in Example 2 except that 0 g / m ^{2 was} applied. The surface of the cement panel develops color immediately after the application of the sodium hydroxide aqueous solution, and the weathering is accelerated in 50 minutes.
A pigmented cement panel with a yellowish brown coating comparable to 0 hours was obtained. This colored cement panel maintained the yellowish brown color tone at the time of manufacture even if it was left outdoors for one year or more, and no change in color tone, fading, white flower phenomenon, etc. were observed.

Example 4 Instead of the sodium hydroxide aqueous solution of PH12 of Example 2, an aqueous solution of hydrogen peroxide having a concentration of 3% by weight was used as an activator.
Steam curing was performed in the same manner as in Example 2 except that 0 g / m ² was used. The surface of the cement panel develops color at the same time as it is impregnated with an aqueous solution of iron sulfate, and after 50 minutes of curing, accelerated weathering 50
A pigmented cement panel with a yellowish brown coating comparable to 0 hours was obtained. The color tone of this colored cement panel was stable even when it was left outdoors for one year or more, and was similar to the yellowish brown color at the time of production. No fading or white flower phenomenon was observed.

Comparative Example 1 An attempt was made to manufacture a colored cement panel in the same manner as in Example 1 except that steam curing in Example 1 was not performed. A thin yellowish brown film was formed on the panel surface as the sprayed iron sulfate aqueous solution was dried, and turned yellowish brown after about 24 hours.
No yellowish brown color comparable to accelerated weathering of 500 hours was reached. After that, when it was left outdoors, the color tone gradually turned to brown and changed to yellow-brown similar to that of Example 1 from half a year to one year.

Example 5 Using a cement panel in which the air curing for 90 days in the production of the cement panel of Example 1 was changed to 180 days, 100 g of an aqueous solution of calcium oxide of PH12 (lime water) was used as an activator. m ² applied, and while the surface of the panel was wet, 80 g of a 20 wt% concentration manganese sulfate aqueous solution was applied.
m ² spray impregnation, wet panel at 80 ° C,
Steam cured for 50 minutes at 98% relative humidity. The surface of the cement panel was colored at the same time as it was impregnated with an aqueous solution of manganese sulfate by spraying to obtain a colored cement panel having a brown film equivalent to accelerated weathering of 500 hours in 50 minutes of curing. This colored cement panel maintained the yellowish brown color tone at the time of manufacture even when it was left outdoors for one year or more, and no fading or white flower phenomenon was observed. It was left warm.

Comparative Example 2 An attempt was made to manufacture a colored cement panel using an aqueous manganese sulfate solution as in Example 5, except that the lime water of Example 5 was not applied and steam curing was not performed. However, the sprayed manganese sulfate aqueous solution penetrated the panel and did not develop color. Then, the operation of spraying a manganese sulfate aqueous solution having a concentration of 20% by weight again at 80 g / m ² was repeated twice, but no color was developed even when the surface of the panel was dried.

Example 6 A cement panel obtained by replacing the air curing for 90 days in the production of the cement panel of Example 1 with 180 days was used, and 100 g of PH12 cement sludge water was used as an activator.
/ M ² applied and the density is 12 while the panel surface is wet.
A weight% aqueous solution of chromium sulfate was impregnated by spraying at 80 g / m ² and the wet panel was steam-cured at 60 ° C. and 60% relative humidity for 50 minutes. The surface of the cement panel develops color at the same time as it is impregnated with an aqueous solution of chromium sulfate by spraying and curing.
A pigmented cement panel with a blue-green coating, which in minutes equals an accelerated weathering of 500 hours, is obtained. Even when the colored cement panel was left outdoors for one year or longer, the blue-green color tone was the same as at the time of production, and no fading or white flower phenomenon was observed.

Example 7 50 g / m ^{2 of an} aqueous solution of sodium chlorate having a concentration of 10 was applied to the cement panel produced in Example 1 as an activator, and chromium sulfate having a concentration of 12% by weight was applied while the panel surface was wet. The aqueous solution was impregnated by spraying at 50 g / m ² , and the wet panel was steam-cured at 60 ° C. and 60% relative humidity for 50 minutes. The surface of the cement panel was colored simultaneously with the impregnation of the aqueous solution of chromium sulfate by spraying, and a colored cement panel having a blue-green film equivalent to accelerated weathering of 500 hours in 50 minutes of curing was obtained. Even when the colored cement panel was left outdoors for one year or longer, the blue-green color tone was as stable as at the time of production, and no fading or white flower phenomenon was observed.

Comparative Example 3 An attempt was made to produce a colored cement panel using an aqueous solution of chromium sulfate as in Example 6 except that the cement sludge water of Example 6 was not applied and steam curing was not performed. However, the sprayed chromium sulfate aqueous solution penetrated the panel and did not develop color. Then, when the operation of spraying a chromium sulfate aqueous solution having a concentration of 12% by weight again at 80 g / m ² was repeated twice, the panel only slightly changed to blue-green.

Example 8 A cement panel obtained by replacing the air curing for 90 days in the production of the cement panel of Example 1 with 180 days was used, and 100 g of an aqueous solution of PH12 water glass was used as an activator.
m ^{2 is} applied, and while the surface of the panel is wet, a copper sulfate aqueous solution having a concentration of 12% by weight is sprayed and impregnated at 70 g / m ² ,
The wet panel was steam aged at 80 ° C. and 60% relative humidity for 50 minutes. The surface of the cement panel was colored at the same time as it was impregnated by spraying with an aqueous solution of copper sulfate, and a colored cement panel having a blue film equivalent to an accelerated weathering resistance of 500 hours in 50 minutes of curing was obtained. Even when the colored cement panel was left outdoors for one year or longer, the blue color tone was the same as that at the time of manufacture, and no fading or white flower phenomenon was observed. It was

Comparative Example 4 An attempt was made to produce a colored cement panel using an aqueous copper sulfate solution as in Example 8 except that the aqueous solution of water glass in Example 5 was not applied and steam curing was not performed. . However, the sprayed copper sulfate aqueous solution penetrated into the panel and did not develop color. Therefore, the copper sulfate aqueous solution having a concentration of 12% by weight was added again to 7
When the operation of spraying 0 g / m ² was repeated twice, the panel only slightly changed to blue.

Example 9 The order of coating and impregnating the aqueous solution of sodium chlorate and the aqueous solution of chromium sulfate in Example 7 was reversed, and 50 g of the aqueous solution of chromium sulfate was used.
/ M ^{2 After} spray impregnation, 50% sodium chlorate solution
Steam curing was performed in the same manner as in Example 7 except that g / m ^{2 was} applied. The surface of the cement panel develops color immediately after the application of the sodium chlorate aqueous solution, and after 50 minutes of curing, accelerated weathering 50
A colored cement panel with a blue-green coating comparable to 0 hours was obtained. This colored cement panel maintained the blue-green color tone at the time of manufacture even if it was left outdoors for one year or more, and no change in color tone, fading, white flower phenomenon, etc. were observed.

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[Procedure amendment]

[Submission date] March 14, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

In the present invention, the metal sulfate is a water-soluble metal sulfate, preferably Group 1B, 6A of the periodic table.
Water soluble metal sulphates selected from the group consisting of Group 7, Group 7A and Group 8 are used. Specific examples of the metal sulfates include water-soluble metal sulfates such as copper sulfate, chromium sulfate, manganese sulfate, iron sulfate, cobalt sulfate and nickel sulfate. The metal sulfates may be used alone or in combination of two or more.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

[0021]

EFFECTS OF THE INVENTION According to the present invention, color development is promoted without defective coloring, and a colored film having a stable color tone can be formed by promptly forming a strong colored film layer, resulting in peeling of the film. Without doing so, it is possible to easily and efficiently produce a colored cement concrete product excellent in long-term weather resistance and stability, and further prevent the whitening phenomenon of the cement concrete product.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

Comparative Example 1 An attempt was made to produce a colored cement panel in the same manner as in Example 1 except that steam curing in Example 1 was not carried out. A thin yellowish brown film was formed on the panel surface as the sprayed iron sulfate aqueous solution was dried, and turned yellowish brown after about 24 hours.
No yellowish brown color comparable to accelerated weathering of 500 hours was reached. After that, when it was left outdoors, the color tone gradually turned to brown and changed to yellow-brown similar to that of Example 1 from half a year to one year.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

Comparative Example 2 An attempt was made to produce a colored cement panel by using an aqueous manganese sulfate solution as in Example 5, except that the lime water of Example 5 was not applied and steam curing was not performed. However, the sprayed manganese sulfate aqueous solution penetrated the panel and did not develop color. Then, the operation of spraying a manganese sulfate aqueous solution having a concentration of 20% by weight again at 80 g / m ² was repeated twice, but no color was developed even when the surface of the panel was dried.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

Comparative Example 3 An attempt was made to produce a colored cement panel using an aqueous solution of chromium sulfate as in Example 6 except that the cement sludge water of Example 6 was not applied and steam curing was not performed. However, the sprayed chromium sulfate aqueous solution penetrated the panel and did not develop color. Then, when the operation of spraying a chromium sulfate aqueous solution having a concentration of 12% by weight again at 80 g / m ² was repeated twice, the panel only slightly changed to blue-green.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

Comparative Example 4 An attempt was made to produce a colored cement panel using an aqueous solution of copper sulfate as in Example 8 except that the aqueous solution of water glass in Example 5 was not applied and steam curing was not performed. . However, the sprayed copper sulfate aqueous solution penetrated into the panel and did not develop color. Therefore, the copper sulfate aqueous solution having a concentration of 12% by weight was added again to 7
When the operation of spraying 0 g / m ² was repeated twice, the panel only slightly changed to blue.

Claims (3)

[Claims] 1. A method for producing a colored cement concrete product, which comprises forming a colored film containing a metal sulfate and / or its reaction product as a main component on the surface of the cement concrete product. A method for producing a colored cement concrete product, which comprises impregnating and / or applying an aqueous solution of a metal sulfate on the surface of the product and then steam curing. 2. A method for producing a colored cement concrete product, which comprises forming a colored film containing a metal sulfate and / or a reaction product thereof as a main component on the surface of the cement concrete product. A method for producing a colored cement concrete product, characterized in that the surface is treated with an activator before or after being impregnated with and / or coated with an aqueous solution of a metal sulfate, and then steam-cured. 3. The colored cement concrete according to claim 2, wherein the activator is an aqueous alkali solution or an aqueous oxidizer solution.
Manufacturing method of products.