JPH0336791B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a decorative cement product in which a glaze is fused to the surface of a cement molded product. Conventionally, this type of manufacturing method, as disclosed in Japanese Patent Publication No. 56-48464, involves making cement molded products using special aggregates such as porcelain shamotsu.
The surface is glazed and heated to 650-900℃, preferably
A decorative cement product is obtained by firing at a temperature of around 800℃ and curing the glazed cement molded product. In addition, other conventional manufacturing methods are disclosed in Japanese Patent Application Laid-Open No. 59-141476.
As disclosed in the publication, in order to increase the strength of decorative cement products, a cement molded product to which a calcium compound has been added is glazed on the surface,
It is fired at a temperature of 650 to 950℃, preferably around 850℃, and the glazed cement molded product is cured.
Obtain cosmetic cement products. However, these conventional methods require a large amount of energy for firing due to the high firing temperature, resulting in high firing costs. Additionally, since the firing temperature is high, if a general aggregate such as sand is used as the aggregate in a cement molded product, it is difficult to fully develop the strength of the cement molded product through curing after firing. However, it is difficult to obtain decorative cement products with high strength. In addition, when the firing temperature is set to a low temperature of 650℃ or less, the glaze that fuses at that temperature is limited to special glazes such as phosphoric acid-based fritted glazes, and the desired glaze is fused to the decorative cement. Can't get the product. Furthermore, in the conventional method, the surface of the cement molded product is rough, so if you do not take the time to seal the surface of the cement molded product with water glass or cement paste before applying the glaze, the cement molded product will not melt. Pinholes and flakes occur on the surface of the applied glaze,
It is not possible to obtain cosmetic cement products with excellent aesthetic appearance. An object of the present invention is to solve the conventional problems as described above. In the conventional method, the reason why the firing temperature is high is that when a glaze is applied to a cement molded article, the melting temperature of the glaze is higher than when it is applied to ceramics. The inventor studied the above phenomenon and found that the phenomenon of increase in the melting temperature of the glaze applied to the cement molded product is not only affected by the thermal conductivity and wall thickness of the cement molded product, but also due to the increase in the melting temperature of the glaze applied to the cement molded product. It was discovered that the roughness and degree of efflorescence on the surface of the cement molded product greatly affected the surface roughness and efflorescence. Therefore, we replaced part of the cement with fly ash to produce a cement molded product with a smooth surface and less efflorescence, and when we applied glaze to this cement molded product and fired it, the glaze lowered the melting temperature. Then, they were fused at a firing temperature of 650°C or less. In other words, if you use a cement molded product in which part of the cement is replaced with fly ash, even if the firing temperature is below 650℃, you can use not only a special glaze with a low melting temperature, but also a special glaze with a low melting temperature.
Common glazes can also be fused, and a decorative cement product with a desired glaze fused can be obtained. In addition, when the firing temperature is lower than 650℃,
It is clear that the firing energy is reduced and the firing costs are lower. In addition, when the firing temperature is lower than 650℃,
Even if cement molded products are made using common aggregates such as river sand or crushed sand, the strength of the cement molded products can be fully developed through curing after firing, making it possible to create highly strong decorative cement products. Obtainable. Furthermore, if a cement molded product is used in which part of the cement is replaced with fly ash, the surface of the cement molded product is smooth, so there is no need to go through the trouble of sealing the surface, and pinpoles can be placed on the glazed surface. It is possible to obtain a cement product with excellent aesthetic appearance without causing any blistering. That is, the present invention provides cement, flyash,
Aggregate and water are kneaded and molded without adding calcium compounds to form a cement molded product, and the surface of the cement molded product is glazed.
Manufacture of a cosmetic cement product characterized by firing at a temperature of 650°C or less to fuse a glaze to the surface of a cement molded product, and curing the cement molded product with the fused glaze to obtain a cosmetic cement product. It is the law. The fly ash used in the present invention is cinder ash generated with the combustion of coal and EP
A general term for ash. The weight ratio of fly ash is preferably 10 to 100% of the weight of cement.
Japanese Industrial Standard Fly Ash Cement (JIS
R5213-1979) does not need to be less than 30% of the total flyash cement amount, but 30%
Mixing the above ingredients is more effective in lowering the melting temperature of the glaze. The aggregate used in the present invention is not limited to special aggregates such as porcelain shamots, but may be general aggregates such as river sand or crushed sand. Moreover, various admixtures such as an AE agent and a water reducing agent may be added as necessary. For molding cement molded products, pour molding method,
Various concrete forming methods are used, such as extrusion molding, press molding, vacuum dehydration, and centrifugal molding, but press molding, vacuum dehydration, and centrifugal molding produce a dense and smooth surface of the cement molded product. preferable. The glaze used in the present invention is not limited to a special glaze with a low melting temperature, but may be a general glaze such as a silicon salt glass glaze. The most preferred glaze is a fritted glaze, which is made by heating lead glaze or boric acid glaze, melting it, and rapidly cooling it to form a glass. The method of applying glaze to the surface of cement molded products includes:
Various methods are used, such as brushing, spraying, roller coating, and soaking. Firing temperature is below 650℃, but between 500 and 650℃
A range of is preferred. If the firing temperature is lower than 500℃,
Glazes that melt at that temperature are limited to special glazes with poor weather resistance and chemical resistance, such as phosphoric acid-based frit glazes. Furthermore, if the firing temperature is higher than 650°C, a decorative cement product with high strength cannot be obtained. The firing time is preferably 5 to 120 minutes, particularly 15 to 30 minutes. General curing methods such as steam curing, autoclave curing, and water curing are used to cure the cement molded product to which the glaze is fused. In the present invention, the reason why the surface of the cement product mixed with fly ash is smooth is that the fly ash has an appropriate fineness and has a smooth spherical shape, which has a bearing effect that improves the fluidity of fresh concrete. by. In addition, the reason why there is little efflorescence on the surface of cement products mixed with fly ash is that most of the fly ash is fine powder, which prevents the formation of rough capillary spaces in the fresh concrete and prevents lime in the cement product from forming. This is due to the difficulty of transferring to the surface of cement products. Next, an experiment to confirm the effects of the present invention will be described. Experiment 1 Test specimens 1 to 4 were prepared by kneading cement, fly ash, aggregate, and water in the weight parts shown in Table 1 below. In each test piece, the cement used was ordinary Portland cement, the fly ash produced at the Takasago Thermal Power Plant, and the aggregate used crushed sand of 5 mm or less. The amount of water was adjusted so that each fresh concrete had almost the same flow.

[Table] Next, each fresh concrete is molded under a molding pressure of 75Kg/cm ²
The material was press-molded and steam-cured at a temperature of 65°C for 5 hours to obtain a cement molded product. The surface of each cement molded product is sprayed with a glaze made by mixing 100 parts by weight of lead monoborate frit with 1 part by weight of bentonite, and heated in an electric furnace at temperatures of 670, 650, 630, 610 or 590℃ for 15 minutes. Bake for a minute. Each test piece was examined for degree of glaze melting, and the results are shown in Table 2 below.

[Table] ○: The glaze is completely melted ×: The glaze is partially or completely melted As is clear from Table 2 above, when fly ash is mixed into cement molded products, firing temperature
The glaze is completely glazed even at temperatures below 650℃. Furthermore, as the proportion of fly ash mixed in increases, the melting temperature of the glaze decreases. Experiment 2 The test piece was made by kneading 70 parts of cement, 30 parts of fly ash, 200 parts of crushed aggregate sand, and 38 parts of water, press molding at a molding pressure of 75 kg/cm ² , and temperature It was steam-cured at 65°C for 5 hours to form a cement molded product. This cement molded product is made in an electric furnace.
15 at each temperature of 400, 500, 600, 630, 700 or 800℃
Bake for a minute. Thereafter, it was steam-cured again at a temperature of 65° C. for 5 hours, and left in the air after steam-curing. The bending strength of the test pieces was measured 7 days after firing, and the results are shown in Table 3 below. The dimensions of the test piece are 50 x 270 x 15 mm, and the test conditions are a span interval of 200 mm, and a loading rate of 2 mm/min.
It is.

[Table] As is clear from Table 3 above, the firing temperature is approximately
At temperatures below 630°C, the bending strength increases as the firing temperature increases;
When the temperature exceeds 700°C, the bending strength decreases as the firing temperature increases. Experiment 3 The test piece was made of cement 70, similar to that of Experiment 2.
part, 30 parts of fly ash, 200 parts of crushed aggregate sand and water.
38 parts were kneaded, press-molded at a molding pressure of 75 kg/cm ² , and steam-cured at a temperature of 65° C. for 5 hours to obtain a cement molded product. This cement molded product was fired in an electric furnace at a temperature of 630°C for 15 minutes. Then temperature 65℃
After steam curing for 5 hours at a temperature of 183°C and a pressure of 10 atm, the specimens were cured in an autoclave for 2 hours at a temperature of 183°C, steam-cured for 5 hours at a temperature of 65°C, and water-cured for 10 minutes, and left in the air after curing. The bending strength of the test pieces was measured 7 days after firing in the same manner as in Experiment 2, and the results are shown in Table 4 below.

[Table] As is clear from Table 4 above, autoclave curing is most preferable for developing strength. Water curing is effective in a short period of time. Experiment 4 Test pieces 11 to 14 were prepared by kneading the same weight parts of cement, fly ash, crushed aggregate sand, and water as in test pieces 1 to 4 of Experiment 1, and press-molding the mixture at a molding pressure of 75 kg/cm ² and at a temperature of 65 kg/cm 2 . It was steam-cured at ℃ for 5 hours to form a cement molded product. Each cement molded product is heated to temperature in an electric furnace.
It was fired at 630°C for 15 minutes, then steam-cured at 65°C for 5 hours, and left in the air after curing. Test piece 11
-14, the bending strength was measured 7 days after firing in the same manner as in Experiment 3, and the results are shown in Table 5 below.

[Table] As is clear from Table 5 above, when fly ash is mixed into a cement molded product, the initial strength decreases. However, the long-term strength is comparable to that without fly ash. In Experiments 1 to 4, steam curing was performed after molding and before firing, but instead of steam curing, underwater curing or autoclave curing may be performed.
No need for curing. Autoclave curing is particularly preferred for lowering the melting temperature of the glaze and developing strength. Effects of the Invention In the present invention, since the firing temperature is a low temperature of 650° C. or lower, the firing energy is small, the firing cost is low, and there is an exceptional practical effect. Furthermore, even at a low firing temperature, not only a special glaze with a low melting temperature but also a general glaze can be fused, and a decorative cement product with a desired glaze fused can be obtained. In addition, since the firing temperature is low, even if the cement molded product is made using general aggregate, the strength of the cement molded product can be fully developed through curing after firing. You can get the product. Furthermore, since the firing temperature is low, a highly strong decorative cement product can be obtained without adding calcium compounds. Furthermore, since the cement molded product containing fly ash has a smooth surface, there is no need to take the time to seal the surface, and pinholes or flakes do not occur on the glazed surface, resulting in a cosmetic cement product with excellent aesthetic appearance. can be obtained. The cosmetic cement product obtained by the present invention is
Used as a building material.

Claims (1)

[Scope of Claims] 1. Cement, fly ash, aggregate, and water are kneaded and molded without adding a calcium compound to form a cement molded product, and the surface of the cement molded product is glazed,
Manufacture of a cosmetic cement product characterized by firing at a temperature of 650°C or less to fuse a glaze to the surface of a cement molded product, and curing the cement molded product with the fused glaze to obtain a cosmetic cement product. Law. 2 The weight ratio of fly ash to cement is
2. The method for producing a decorative cement product according to claim 1, wherein the ratio is 0.1 to 1. 3. The method for producing a decorative cement product according to claim 1 or 2, characterized in that the firing temperature is 500°C or higher.