JPH11349388A - Production of concrete panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a concrete panel having sufficient hardness irrespective of the time setting of temporary curing process. SOLUTION: A concrete slurry 7 is placed on a frame mold 1 coated with a releasing agent. Then a temporary curing process is carried out while keeping an exposed surface 7a of the concrete slurry 7 in a maintained state of wet atmosphere by covering the exposed surface 7a of the concrete slurry 7 with a vinyl sheet 9 to make the concrete slurry 7 into a concrete panel 7' having a reduced fluidity. The concrete panel 7' is removed from the frame mold 1, the concrete panel 7' is sprinkled with water and the concrete panel 7' is then cured in a high-temperature high-pressure atmosphere in an autoclave.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a concrete panel, and more particularly to a method for manufacturing a concrete panel by casting a concrete slurry into a formwork and molding.

[0002]

2. Description of the Related Art As a lightweight concrete panel having excellent heat insulating properties, a lightweight cellular concrete panel containing air bubbles is frequently used. In order to manufacture such a concrete panel, after a casting step of casting a concrete slurry into a mold to which a release agent has been applied, the concrete slurry poured into the mold is held at a normal temperature. Perform the curing process. In this temporary curing step, the hydration reaction of the concrete slurry proceeds, and the fluidity of the concrete slurry is reduced to form a concrete panel. Next, the concrete panel is removed from the formwork, and after the concrete panel is steam-cured (having a humidity of 100% or more) in the pre-curing step, the concrete panel is held in a high-temperature and high-pressure atmosphere in an autoclave (pressure steam pot). Perform a curing process. In this curing step, the hydrothermal reaction proceeds in the concrete panel, and the hardening of the concrete panel is promoted.

[0003]

However, the above-mentioned method for manufacturing a concrete panel has the following problems. That is, in the temporary curing step, there is a reaction time required for the fluidity of the concrete slurry to be sufficiently reduced to form a concrete panel. It is considered that the reaction time is preferably short from the viewpoint of productivity, and the time of the temporary curing step is generally set in accordance with the reaction time. However, from the viewpoint of work efficiency, there is a case where a time significantly exceeding the reaction time is set as the temporary curing step. For example, when the above reaction time is about 2 hours, and when the casting step is completed, the work on that day must be stopped and the demolding step must be performed on the next day, the reaction time (2 hours) ).

[0004] In such a case, the exposed surface of the concrete slurry cast in the mold remains exposed to the atmosphere for a long time. For this reason, the moisture in the concrete slurry (concrete panel) evaporates from the exposed surface and the water content decreases, and the release agent is absorbed into the concrete panel by the amount of the lost water. In the curing step, the release agent absorbed in the concrete panel inhibits hardening of the concrete panel due to a hydrothermal reaction. As a result, depending on the setting of the time of the temporary curing step, it is not possible to obtain sufficient hardness in the manufactured concrete panel.

[0005]

According to the present invention, there is provided a method of manufacturing a concrete panel, comprising: casting a concrete slurry into a mold having a release agent applied thereto; A method for manufacturing a concrete panel, comprising: a temporary curing step of holding the concrete slurry in a frame to make the concrete slurry into a concrete panel with reduced fluidity; and a demolding step of demolding the concrete panel from the mold. It is. Particularly, in the temporary curing step, the exposed surface of the concrete slurry is squeezed and maintained in an atmosphere.

In the above manufacturing method, the temporary curing step is performed in a state where the exposed surface of the concrete slurry is kept in a squeezed atmosphere, so that moisture is prevented from evaporating from the exposed surface of the concrete slurry in the temporary curing step. Therefore, the water content in the concrete panel in which the fluidity of the concrete slurry is reduced is secured, and the absorption of the release agent into the concrete panel is suppressed.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are sectional process diagrams for explaining an example of a method for manufacturing a concrete panel according to the present invention. Here, a method for manufacturing a concrete panel according to an embodiment of the present invention will be described with reference to an example of manufacturing a lightweight cellular concrete panel containing air bubbles. Will be described.

First, as shown in FIG. 1A, a mold 1 is prepared, a wire mesh 3 is arranged in the mold 1, and a concrete slurry 7 is poured into the mold 1 by a bucket 5. The casting process is performed. The mold 1 has a rectangular shallow box shape with an open upper surface, and a release agent is applied to the inner wall. The concrete slurry 7 contains air bubbles.

Next, as shown in FIG. 1 (2), a temporary curing step of holding the concrete slurry 7 in the mold 1 at normal temperature is performed. Here, the exposed surface 7a of the concrete slurry 7 (that is, the surface that is not in contact with the mold 1) is covered with a sheet made of a material that does not transmit moisture, such as a vinyl sheet 9. As a result, the water vapor evaporated from the concrete slurry 7 is stopped above the exposed surface 7a covered with the vinyl sheet 7 without diverging into the atmosphere, and the exposed surface 7a is kept in a squeezed atmosphere.
For example, the vinyl sheet 9 may have a sufficient size so that the periphery thereof hangs down on the side circumference of the mold 1 so that the exposed surface 7a is surely covered.

In the temporary curing step, the hydration reaction of the concrete slurry proceeds, and the fluidity of the concrete slurry 7 is reduced to form a concrete panel. Here, at least a time longer than the reaction time necessary for the fluidity of the concrete slurry 7 to sufficiently decrease to form a concrete panel is set as the time of the temporary curing step. For example, when the reaction time is 2 hours, the provisional curing step is set to 2 hours or more.

Next, as shown in FIG. 1 (3), the vinyl sheet (9) is peeled off from the exposed surface 7a of the concrete panel 7 'in which the fluidity of the concrete slurry (7) has been reduced by the temporary curing step. A demolding step of demolding the concrete panel 7 'from the mold 1 is performed. This demolding step is performed, for example, on the day after the casting step is performed. In this case, the temporary curing step described with reference to FIG. 1 (2) is set to a time (for example, 12 hours) that greatly exceeds the reaction time (2 hours).

After performing the steps up to the demolding process as described above, as shown in FIG. 2A, a plurality of demolded concrete panels 7 'are placed on a gantry 11, and these concrete panels 7' are placed. Perform the pre-curing process for '.

Thereafter, as shown in FIG. 2B, these concrete panels 7 'mounted on the gantry 11 are housed in an autoclave (pressure cooker) 15, and the interior of the autoclave 15 is exposed to a high-temperature and high-pressure atmosphere. I do. by this,
The hydrothermal reaction in the concrete panel 7 'is advanced to harden the concrete panel 7'.

According to the above manufacturing method, as described with reference to FIG. 1B, the exposed surface 7a of the concrete slurry 7 is covered with the vinyl sheet 9 so that the exposed surface 7a of the concrete slurry 7 is squeezed to an atmosphere. The temporary curing process is performed while maintaining the condition. For this reason, a large amount of water is prevented from evaporating from the concrete slurry 7 and the exposed surface 7a of the concrete panel whose fluidity has decreased in the temporary curing step. Therefore, the water content in the concrete panel is ensured, and the absorption of the release agent from the inner wall of the formwork 1 into the concrete panel is suppressed.

As a result, even if a time (for example, 12 hours) that is much longer than the reaction time (2 hours) is set as the time for the provisional curing step, a large amount of the water from the exposed surface 7a is generated. The absorption of the release agent into the concrete panel 7 'due to the evaporation of water can be prevented. For this reason, in the curing step described with reference to FIG. 2B, the hydrothermal reaction in the concrete panel 7 'is not inhibited by the release agent regardless of the set time of the temporary curing step. Thus, the concrete panel 7 'can be reliably cured. In addition, from this, the selection range of the set time of the temporary curing process is widened, and it is possible to improve the working efficiency.

In the above-described embodiment, as a method of keeping the exposed surface 7a of the concrete slurry 7 (including concrete panels with reduced fluidity of the concrete slurry) in a temporary curing step, the exposed surface 7a of the concrete slurry 7 is The method of covering with a sheet (vinyl sheet 9) is exemplified. However, the technique is not limited to the exemplified technique. For example, a lid made of a material that does not allow moisture to pass through may be placed on the exposed surface 7a side of the concrete slurry 7. Further, the formwork 1 on which the concrete slurry 7 is cast may be stored in a room kept in a high humidity atmosphere. Further, water vapor may be supplied to the exposed surface 7a of the concrete slurry 7.

Further, in the above embodiment, the case of manufacturing a lightweight cellular concrete panel containing cells has been described. However, the present invention is widely applicable to a method of manufacturing a concrete panel by casting a concrete slurry in a mold and casting the slurry.

[0018]

As described above, according to the method for manufacturing a concrete panel of the present invention, the provisional curing step is performed in a state where the exposed surface of the concrete slurry is squeezed and kept in an atmosphere, thereby reducing the water content in the concrete panel. Thus, absorption of the release agent into the concrete panel can be suppressed. For this reason, even if the setting time of the temporary curing step is long, it is possible to perform the concrete panel processing step (for example, the curing step) without being affected by the release agent after the demolding step. As a result, it is possible to obtain a concrete panel having a sufficient hardness regardless of the time setting of the temporary curing step.

[Brief description of the drawings]

FIG. 1 is a sectional process diagram (part 1) for explaining an example of a method for manufacturing a concrete panel of the present invention.

FIG. 2 is a sectional process view (part 2) for explaining an example of the method for manufacturing a concrete panel of the present invention.

[Explanation of symbols]

1 ... formwork, 7 ... concrete slurry, 7 '... concrete panel, 7a ... exposed surface

Claims (1)

[Claims] 1. A casting step of pouring a concrete slurry into a mold to which a release agent has been applied, and a concrete panel holding the concrete slurry in the mold and reducing the fluidity of the concrete slurry. In the method for producing a concrete panel, a temporary curing step to be performed and a demolding step of removing the concrete panel from the mold are performed. In the temporary curing step, the exposed surface of the concrete slurry is maintained in a squeezed atmosphere. A method of manufacturing a concrete panel.