JPH0322282B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention provides gravel exposed on one side of a product,
This invention relates to a method for manufacturing concrete products that have a rough surface because coarse-grained sand slightly protrudes from the mortar consisting of cement and sand.

(Prior art) The conventional method of creating a rough surface in concrete is to spread a retarder to delay the solidification of cement at the bottom of a pour molding form, and then to place a concrete material containing decorative gravel on top of the retarder. After pouring regular concrete material on top of it, let it cure and harden as appropriate.
Once the mold is opened and demolded, the surface mortar (cement and sand) that has not solidified due to the permeation of the retarder is washed away with water and a brush, commonly known as the washing-out method.

Instead of directly laying the retardant on the bottom of the formwork, a method has also been announced in which a sheet coated with the retardant is placed.

(Problems to be solved by the invention) This invention mass-produces rough-surfaced concrete products that do not require height differences such as the washing-out method described above, using an immediate demolding method without the conventional elaborate hardening delay treatment. A new manufacturing method was developed.

(Means for Solving the Problems) This invention packs hardened concrete into a mold that can be turned upside down in an instant demolding molding device, and places a mold on the top surface of the packed concrete up to the depth of the mortar that is to be removed. Water containing acid or a coagulation retardant is sprayed or sprinkled so that it permeates almost uniformly, and then a surface pallet covering the top of the concrete is immediately placed face down, and the formed concrete placed on the surface pallet is removed by inversion and demolding. This is a method for producing a rough surface concrete product, which is characterized in that the surface pallet is removed, and after curing, the surface pallet is peeled to remove the unsolidified upper layer mortar from the surface of the formed concrete.

(Function) This invention also has the same basic principle of delaying the hardening of the concrete surface layer mortar as the conventional one. However, the method has changed significantly; in other words, the application target is the concrete surface that comes into contact with the surface pallet of the inverted instant demolding molding equipment, which was previously completely unthinkable, and the main ingredient of the solidification retarder is water, and this is applied to the formwork. Instead of laying it on the bottom of the concrete, spray or spread it on the surface of the formed concrete. Immediately turn the surface pallet face down on the watered surface and pour the water-containing surface cement and fine-grained sand onto the surface pallet. This invention introduced a new technique for making concrete rough surfaces, such as peeling off the surface pallets and removing surface mortar after curing.

The hardened concrete packed into the formwork is usually made almost homogeneous by vibration and pressure, and the upper surface of the concrete that appears at the concrete inlet of the formwork is made smooth by a press plate. The water removed to the top surface permeates to a depth of several millimeters, that is, the thickness of the mortar to be removed, giving it fluidity. Before the mortar that has gained fluidity settles due to gravity, it is applied to a face pallet and inverted to remove the mold, so the mortar is caught on the inner surface of the face pallet. When the pallet is cured in this state and properly cured, when the surface pallet is peeled off as usual, the mortar on the inner surface that could not be cured by the setting retarder is removed from the product.

(Example) FIG. 1 shows a schematic cross-sectional view of a place where hardened concrete C is packed into a mold M of an instant demolding molding device. Unlike poured concrete, mortar consisting of cement and fine-grained sand is packed between two layers of gravel or coarse-grained sand. Hard-mixed concrete has many voids remaining. When pouring concrete, divide it into two layers, with the lower part using the normal mix and the upper part using concrete with a mix of decorative gravel with a lot of voids, or by minimizing vibration and pressure after the mix is poured. The number of voids may be increased artificially.

Since the mortar component 2 of the hardened concrete C has a low moisture content, it often acts as a bridge between the gravel 1 and cannot move. Therefore, when water is added to this, fluidity is obtained.

In this invention, water that has a solidification retarding effect is sprayed or sprinkled on the upper surface of the concrete in the formwork.
The amount is small enough to provide fluidity to the upper layer of mortar (cement and fine sand), which is several mm thick.
FIG. 2 shows the state in which the immediate pallet p is placed face down. 2' indicates the mortar content consisting of cement and fine sand containing the given water.

After the surface pallet P is turned upside down, the formwork M is immediately turned over and the concrete is removed from the mold as usual. FIG. 3 shows the internal state of demolded concrete C when it is carried out on a surface pallet P. The surface mortar portion 2' containing sufficient water has settled and accumulated on the pallet P. Gravel and part of coarse sand 1 are soaked there.

This is then sent to a curing facility or elsewhere, and when it has properly hardened, the surface pallet P is peeled off from the product C.
As shown in the figure, the unsolidified mortar 2' remains on the pallet P as cement and fine-grained sand, and the surface side of the concrete product that has lost it is covered with gravel and coarse-grained sand 1. It sticks out and has the rough surface I was looking for.

In the experiment, the mortar component 2' lost moisture during curing and turned into powder when the surface pallet was peeled off.

The composition of the concrete of the above example is shown below.

White cement 6.4Kg Ordinary cement 0.7Kg Granite sand (5mm) 3.6Kg Granite sand (2.5mm) 12.0Kg Granite sand (2.5mm or less) 9.6Kg Black mist (2mm) 8.4Kg Water 1.7Kg The resulting rough surface will have powder on it when the surface pallet is removed, but it can be easily brushed off with a brush or washed with water.
It can be finished neatly. At this stage, the concrete has not yet hardened sufficiently, so if you scrub it vigorously with a brush as in the washing method, there is a risk that mortar that does not need to be removed may be removed. In such cases, spray water containing the above-mentioned coagulation retarder,
Before spreading, the resin-containing water is sprayed a little harder to penetrate deeper, and then the water containing the retarder, which prevents the resin and cement from solidifying, is removed.

In addition, the range of application by engineers is wide, such as adding a coloring agent to the sprayed water and leaving some of it on the product side to obtain a colored rough surface.

(Effects of the invention) Because the mortar in hardened concrete lacks moisture, it forms a bridge between the gaps between the gravel. According to this invention, water is applied to the surface layer to a thickness of several millimeters, and the surface layer is immediately removed. If you flip the palette face down,
The mortar that has gained fluidity is placed on the surface pallet. Because the water contains acid or a coagulation retarder, the cement does not solidify during curing, and the surface pallet peels off and falls off the product surface, leaving a rough surface with gravel and coarse sand remaining as fine protrusions. Become a face.

In this way, the present invention has opened the way for the first time to roughen the surface of a product in which the surface pallet of the inverted instant demolding molding method is turned upside down. Since it only adds one step of spraying and sprinkling water to the conventional process of the above-mentioned highly productive forming method using hardened concrete, it is more efficient than all conventional rough surface forming methods. Low cost.

[Brief explanation of the drawing]

Each figure is an explanatory view of one embodiment of this invention.
The figure shows the state in which water was sprayed or sprinkled on the top surface and the surface pallet P was immediately turned upside down, Figure 3 shows the state in which the mold was reversed and the product was removed from the mold, and Figure 4 shows the surface pallet P after being properly cured. This figure shows the state in which the pallet P has been peeled off. 1... Gravel or coarse sand, 2... Mortar content,
2'... Mortar containing water.

Claims (1)

[Claims] 1. Pack hardened concrete into a formwork that can be turned upside down in an instant demolding molding device, and add acid or a setting retarder to the top surface of the packed concrete so that it penetrates almost uniformly to the depth of the mortar that is to be removed. Spray or sprinkle water on it, and immediately
The surface pallet covering the top surface of the concrete is placed face down, and the molded concrete placed on the surface pallet is removed by inversion demolding. After curing, the surface pallet is peeled off and the unsolidified upper layer mortar is removed from the surface of the molded concrete. A manufacturing method for rough concrete products that is characterized by the removal of