JPH0335276B2 - - Google Patents

Description

[Detailed description of the invention]

B. Field of Industrial Application The present invention relates to an improvement in a method for producing a glazed concrete molded body. B. Prior Art Conventionally, glazed concrete molded bodies have been attracting attention as building materials, especially for exterior materials, because they are durable and beautiful. The method for manufacturing the glazed concrete molded body is to first pour a concrete mixture into a formwork,
Vibration molding is performed, and the mold is removed and dried to create a hardened base concrete. Next, a glaze is applied to the surface of the cured concrete. Generally, the surface of a cured concrete has many pores, and if the glaze is applied as is, pinholes will be formed from the pores on the surface and penetrate through the glazed layer.
When this material is used as an exterior material, there are drawbacks such as rainwater entering through the pinholes or differences in color appearing in the pinholes, which impairs the aesthetic appearance. Therefore, in order to prevent the formation of pinholes, work has been carried out to fill in the pores on the surface of the hardened concrete body, that is, sealing work. As a sealing material, a mixture of cement and fine mineral powder or glaze itself is used. After sealing, glazing was applied to produce glazed concrete molded bodies. C. Problems to be Solved by the Invention However, in the past, this sealing work was done manually, and it was not possible to completely seal the large number of pores dispersed on the surface of the hardened concrete. A drawback of glazing was that pinholes could not be completely eliminated. D. Means for Solving the Problems In order to solve the above-mentioned drawbacks, the inventors of the present invention conducted research on a method for producing a hardened concrete body without pores on the surface, and as a result, the present inventors developed a method of vibration-molding a mortar mixture with a special composition. As a result, the present invention was completed based on the knowledge that no pores are formed on the surface of the mortar in contact with the formwork, and that by glazing this surface, a glazed concrete molded body without pinholes can be obtained. That is, the present invention has a water-cement ratio (W/C) of 50 to
A mortar mixture of 100% and a sand-cement ratio (S/C) of 160 to 420% is poured into a formwork, compacted by vibration, floating water is discharged, and the surface mortar is formed, after which a lining concrete is formed on top of it. The present invention provides a method for producing a glazed concrete molded body, characterized in that the surface layer mortar is glazed after being removed from the mold and dried. The present invention will be explained in detail below. In the present invention, commonly used mortar raw materials can be used as they are for producing the mortar mixture. In other words, the cement used is Portland cement, mixed cement, etc., and the sand used was river sand, sea sand, etc.
Examples include crushed sand, artificial light bones, sandstone, anti-firestone, etc. Examples of raw materials for producing the lining concrete mixture include cement and sand, which are the raw materials for the mortar mixture described above, and examples of the coarse aggregate include river gravel, crushed stone, artificial lightweight aggregate, and the like. In addition, it is possible to appropriately mix admixture materials used in general concrete, such as strength extenders, high-performance water reducing agents, thickeners, antifoaming agents, fibers, etc., into the concrete mixture. . Next, the blending ratio of these raw materials will be described. In the case of a mortar mixture, the blending ratio of cement is preferably such that at least when vibration compaction is performed, the space between the sands is filled with cement.
It is necessary to add a relatively large amount of kneading water so that air bubbles in the mortar mixture can be easily removed during vibration compaction. Specifically shown in numerical values, W/C = 50 to 100%,
S/C=160-420%, preferably W/C=
60-80%, S/C=200-300%. If W/C is less than 50% and S/C is less than 160%, compaction will not be sufficient, and if W/C is more than 100% and S/C is more than 420%, it will be due to poor mix. The cement particles are not sufficiently distributed between the sands and there is too much water, which weakens the strength and makes it impractical. The blending ratio of raw materials in the concrete kneaded product is determined depending on the strength required for the glazed concrete molded body, and is not particularly limited. Next, the manufacturing method will be described. After mixing sand, cement, and water in the above ratio, they are poured into a mold, and the mold is vibrated with a vibrator to compact the mortar mixture. Floating water and cement paste that float to the surface due to vibration are removed from within the formwork. The surface mortar is formed by the above operations. Usually, the thickness of surface mortar is 3~
5 mm is preferred. On the other hand, a concrete mixture for lining is prepared in advance, and the mixture is poured onto the formed surface mortar and compacted by applying appropriate vibrations or the like. After curing and hardening the mortar-concrete unit in a conventional manner as described above, it is removed from the mold and dried to obtain a molded body. The mortar surface of the molded body is glazed by a conventional method. In this way, a glazed concrete molded body having a beautiful glazed surface without pinholes is obtained. Hereinafter, the present invention will be explained with reference to Examples. E. Examples Examples and Comparative Examples Mortar and concrete mixtures were kneaded using the raw materials and mixing ratios shown in Tables 1 and 2, respectively. Mortar mixture prepared in advance 100×
The mixture was poured into a 100 x 4 cm mold to a thickness of 5 mm, and after vibrating compaction for 1 minute, floating water was removed and a surface mortar was formed. Then, immediately

【table】

【table】

[Table] A concrete mixture was poured onto the rutar so that the total thickness of the molded product was 4 cm, and vibration compaction was performed for 15 seconds to obtain an integrated mortar and concrete product. After the integrated product was cured in the air for 24 hours, it was demolded and dried at 200° C. for 12 hours to obtain a molded product. A slip of glaze (manufactured by Nippon Horo Glaze Co., Ltd., trade name "7321") was sprayed onto the mortar surface of the molded body, and then heated in an electric furnace at 900°C for 5 hours to obtain a glazed concrete molded body. Table 1 shows the observation results of the glazed surface of the obtained molded body. F. Effects of the invention In the conventional manufacturing method of glazed concrete molded bodies, in which the surface is sealed and glazed after concrete is formed, it was not possible to completely prevent pinholes from forming on the surface. By vibrating and compacting the blended mortar to form a surface mortar, and then glazing the mortar surface, a glazed concrete molded body with no pinholes, improved waterproof performance, and no uneven color on the glazed surface can be obtained. can get.

Claims (1)

[Claims] 1 Water cement ratio 50~100%, sand cement ratio 160~
Pour the 420% mortar mixture into the formwork, compact it by vibration, drain the floating water, form the surface mortar, form the lining concrete on top of it, remove the mold and dry it, then glaze the surface mortar. A method for producing a glazed concrete molded body, characterized by: