JPH038782A - Production of glazed cement product - Google Patents

Abstract

PURPOSE:To prevent cracking and destruction by coating the exterior surface of plain cement product of thin hollow shape with glaze, calcining and packing cement or concrete to the hollow part. CONSTITUTION:Cement is blended with fine aggregate, water and an admixture to give mortar or concrete, which is subjected to cast molding and cured to give a plain cement product 1 of thin hollow shape. Then glaze is applied to adjoining two faces 2 on the exterior surface of the product 1, the product is calcined and cured to fuse the glaze to the exterior surface 2. Then plural reinforcing bars 4 are arranged in the hollow part of the product 1, if necessary and mortar or concrete is packed into the hollow part to give a lump or thick glazed (reinforced) cement product of collapsed shape.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for manufacturing a glazed cement product in which a glaze is fused to the surface of a solid cement product in the form of a lump or a thick wall.

<Prior art> In this type of manufacturing method for glazed cement products, mortar or concrete is poured into a lumpy or thick solid shape to form a reinforcing bar or unreinforced cement product in the desired shape. .

Next, a glaze is applied to the surface of this cement product, and the cement product with the glazed surface is fired at a temperature of about 500 to 900°C to fuse the glaze to the surface of the cement product.
A glazed cement product having a solid shape of a lump or a thick wall is obtained.

<Problems to be Solved by the Invention> However, the glazed cement products obtained by the above manufacturing method often have cracks or destruction.

Further, when the glazed cement product is a reinforced cement product with embedded reinforcing bars, the reinforcing bars in the glazed cement product often deteriorate and the yield point of the reinforcing bars decreases.

That is, in the above-mentioned manufacturing method, it is difficult to obtain a solid-shaped reinforcing bar or unreinforced glazed cement product in the form of a block or thick wall that is free from cracks and fractures.

Furthermore, it is difficult to obtain a solid-shaped glazed reinforcing bar cement product in the form of a lump or a thick wall in which the yield point of the reinforcing bar is not lowered.

An object of the present invention is to solve the conventional problems as described above.

Causes of problems In the above manufacturing method, the following are possible causes of cracks and destruction of glazed cement products.

When firing a glazed cement product, the surface of the cement product will rise quickly and the internal temperature will rise slowly, resulting in a large temperature difference between the surface and the inside.
A large difference occurs between the amount of thermal expansion on the surface and the amount of thermal expansion inside.

In addition, when cement products are fired, the moisture inside them evaporates and expands, but with cement products that are lumpy or thick-walled, it is difficult for the moisture inside them to escape to the outside, and the moisture generated inside the cement products is difficult to escape. Large expansion pressures are generated.

In particular, when a cement product is cast and molded, the moisture content of the cement product is high, so the expansion pressure due to the water vapor generated inside is extremely high.

When the glazed cement product is a reinforced cement product with embedded reinforcing bars, the thermal expansion characteristics of the reinforcing bars and mortar or concrete are different, so there is a difference between the thermal tension of the reinforcing bars and the amount of thermal expansion of the mortar or concrete.

The reinforcing steel expands in proportion to temperature until it reaches a temperature of 800-900°C.

On the other hand, the thermal expansion characteristics of mortar or concrete vary depending on the type and blending ratio of the materials, but in terms of boat fishing, mortar or concrete can The amount of expansion is small, but the transformation temperature of quartz contained in quartzite and sandstone is 550-6.
When the temperature reaches 00°C, the amount of expansion increases rapidly and does not expand in proportion to the temperature. Furthermore, when andesite or basalt is used as aggregate, the amount of expansion is smaller than that of reinforcing steel.

In particular, mortar or concrete is resistant to compression, but
Since it is weak in tension, if the reinforcing steel expands more than the mortar or concrete, tensile stress will be generated in the mortar or concrete, making it prone to cracking.

Furthermore, in the above manufacturing method, the following is considered to be the primary reason why the reinforcing bars in the glazed cement product deteriorate and the yield point of the reinforcing bars decreases.

The reinforcing bars in cement products are heated to a high temperature during firing of the cement product, and then gradually cooled down, so that the reinforcing bars are annealed.

Means for Solving the Problems> The present invention involves first manufacturing a thin-walled, hollow, unreinforced glazed cement product, and then placing reinforcing bars in the hollow portion of the thin-walled, hollow, unreinforced glazed cement product. Alternatively, it is not placed and filled with mortar or concrete to obtain a lumpy or thick-walled, solid-shaped reinforcing bar or unreinforced glazed cement product.

That is, in the present invention, mortar or concrete is formed into a thin-walled, hollow shape to form a thin-walled, hollow, unreinforced cement product.

Glaze is applied to the outer surface of the cement product, and the cement product with the glaze applied to the outer surface is fired to fuse the glaze to the outer surface of the cement product.Then, the hollow part of the cement product is filled with mortar or concrete to form a block or This is a method for producing a glazed cement product, which is characterized by obtaining a thick-walled, solid-shaped glazed cement product.

Furthermore, the present invention involves forming mortar or concrete into a thin hollow shape to form a thin hollow unreinforced cement product, applying a glaze to the outer surface of the cement product, and firing the cement product with the glaze applied to the outer surface. Then, the glaze is fused to the outer surface of the cement product, and then reinforcing bars are placed in the hollow part of the cement product and filled with mortar or concrete to obtain a glazed reinforced cement product with a solid shape in the form of a lump or thick wall. This is a method for manufacturing glazed cement products characterized by the following.

Effect> In the manufacturing method of the present invention, since the cement product to be fired is thin-walled and hollow, the temperature difference between the surface and the inside of the cement product is small, and the difference in thermal expansion between the surface and the inside of the cement product is small. small.

Moreover, since the cement product to be fired is unreinforced, there is no difference in the amount of thermal expansion between reinforcing steel and mortar or concrete.

Furthermore, since the cement product to be fired is thin and hollow, the water vapor generated inside the cement product can easily escape to the outside during firing, and the expansion pressure generated by the water vapor inside the cement product is small.

In the production method of the present invention, when producing a glazed reinforced cement product with embedded reinforcing bars, the fired cement product is unreinforced, so there is no difference in the amount of thermal expansion between the reinforcing bars and mortar or concrete.

In addition, the cement products to be fired are unreinforced, and the reinforcing bars are
Since the reinforcing bars are placed in the hollow part of the cement product after the cement product is fired, the reinforcing bars are not heated to a high temperature and the reinforcing bars are not annealed.

<Effects of the Invention> In the manufacturing method of the present invention, the difference in the amount of thermal expansion between the surface and the inside of the cement product to be fired is small, and furthermore, there is no difference in the amount of thermal expansion between reinforcing bars and mortar or concrete. Moreover, since the expansion pressure generated by the water vapor generated inside the cement product is small, it is possible to obtain a glazed cement product in the form of a block or thick solid without cracking or destruction.

Further, in the manufacturing method of the present invention, since the reinforcing bars are not annealed, a glazed reinforcing bar cement product in the form of a lump or a thick solid material whose yield point is not lowered can be obtained.

<Example> The manufacturing method of this example involves pouring and molding a mortar prepared by kneading 100 parts by weight of cement, 300 parts by weight of crushed fine aggregate, 35 parts by weight of water, and 1 part by weight of an admixture. forming a box-shaped, thin-walled, hollow unreinforced cement product l;
Which cement product 1 is steam cured at a temperature of 70°C for 3 hours.

Note that 1. The above mortar may be concrete containing coarse aggregate, and the above steam curing may be autoclave curing, air curing, or underwater curing.

Next, the cement product 1 is coated with a glaze on two adjacent outer surfaces 2, fired at a temperature of 850° C. for 1 hour, slowly cooled, and then cured in water for 1 day.

Note that this curing may be steam curing or autoclave curing.

That is, a box-shaped, thin-walled, hollow, unreinforced cement product 1 with glaze fused to two adjacent outer surfaces 2 is manufactured.

Thereafter, a plurality of reinforcing bars 4 are placed in the hollow part 3 of the cement product 1, as shown in FIG. A mortar 5 in which 1 part by weight of the agent was kneaded was packed.

Note that this filling mortar 5 may be concrete containing coarse aggregate.

That is, a glazed reinforcing cement product l having a substantially rectangular solid shape with glaze fused to two adjacent surfaces 2 is manufactured.

As shown in Fig. 3, the solid-shaped glazed reinforcing cement product l obtained by the manufacturing method of this example is produced in large numbers along the stepped part of the drainage ditch between the sidewalk and the roadway S. are arranged, and two adjacent surfaces 2 of the surfaces fused with glaze, that is, the decorative surfaces 2 of the glazed surfaces, are placed at exposed positions visible to pedestrians and people in cars, and used as boundary blocks.

Moreover, a large number of blocks are arranged along the periphery of a raised flower bed, and the decorative surface 2 is placed in an exposed position, and used as a curbstone block.

In the manufacturing method of this example, since the filling mortar 5 contains an expanding material, the adhesion between the cement product 1 and the filling mortar 5 is good.

In the manufacturing method of this example, the reinforcing bars 4 are arranged in the hollow part 3 of the cement product 1, but the reinforcing bars 4 may not be arranged if they are not necessary for the sake of strength.

In addition, a hollow cement product 1 was formed into a box shape, and the hollow part 3 of the cement product 1 was filled with mortar 5 to form a solid glazed cement product l into a substantially rectangular parallelepiped shape. As shown in the figure, a thin-walled hollow cement product 11 is formed into a flat cylindrical shape, and the hollow part 13 of the center hole of the cement product 11 is filled with mortar or concrete with or without reinforcing bars. The solid-shaped glazed cement product 1 may be made into a thick plate shape.

Moreover, although the decorative surface 2 to which the glaze is fused is formed on a part of the outer surface of the cement product 1, it may be formed on the entire outer surface of the cement product.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an intermediate cement product obtained by a manufacturing method according to an embodiment of the present invention. FIG. 2 is a perspective view of the final glazed reinforced cement product obtained by the rolling manufacturing method. FIG. 3 is a sectional view showing an example of use of the glazed reinforced cement product. FIG. 4 is a perspective view of an intermediate cement product obtained by a manufacturing method of another example. l: Cement product 2: External surface 2 Surface 3: Hollow part
4: Rebar 5: Filled mortar

Claims (1)

[Scope of Claims] 1 Mortar or concrete is formed into a thin-walled hollow shape to form a thin-walled hollow unreinforced cement product, the outer surface of the cement product is glazed, and the glaze is applied to the outer surface of the cement product. It is characterized by firing to fuse the glaze to the outer surface of the cement product, and then filling the hollow part of the cement product with mortar or concrete to obtain a glazed cement product in the form of a block or thick solid. Method of manufacturing glazed cement products. 2. Mortar or concrete is formed into a thin-walled, hollow shape to form a thin-walled, hollow, unreinforced cement product, the outer surface of the cement product is glazed, and the glazed cement product is fired to remove the glaze. It is characterized by being fused to the outer surface of the cement product, and then placing reinforcing bars in the hollow part of the cement product and filling it with mortar or concrete to obtain a glazed reinforced cement product with a solid shape in the form of a lump or thick wall. Method of manufacturing glazed cement products.