JP2011056767A - Method for manufacturing concrete product, film sheet used for the method, and concrete product manufactured by the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a concrete product by which the surface is finished without forming any large crayon-pastel recess by bubble traces when manufacturing the concrete product. <P>SOLUTION: The method for manufacturing high-strength concrete 2 includes: a step of placing high-strength concrete 2 in a mold form 1; a step of vibrating the mold form 1 having the concrete 2 placed therein to degas it; a step of steam-curing the high-strength concrete 2 in the mold form 1; and a step of covering a film sheet 3 where a plurality of small holes 3a are arrayed at predetermined intervals on the surface 2a of the concrete 2 exposed to the opening of the mold form 1. Then, a curing sheet 5 containing moisture is stacked on the film sheet 3 to be cured, bubbles P floating from the concrete 2 are degassed through the small holes 3a of the film sheet 3, and the moisture is entered through the small holes 3a to prevent wrinkling of the surface 2a. Thus, the high-strength concrete 2 is cured to manufacture a high-strength concrete product. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a concrete product manufacturing method for manufacturing various concrete products such as columns, beams, and segments in advance in a factory, a film sheet used in the manufacturing method, and a concrete product manufactured by the manufacturing method.

Conventionally, as a structural PC, there is a concrete product used for a pillar, a beam, or the like of an apartment. For example, there is a concrete product described in Patent Document 1 below.
As such a precast concrete product, for example, a high strength concrete having a high strength of 60 N / mm ² or more is used. This high-strength concrete is manufactured in advance in a factory, transported to a construction site, etc., and installed and constructed.
By the way, when manufacturing high-strength concrete products in a factory, usually, high-strength concrete kneaded is placed in a formwork with openings as in general concrete, and then the formwork is vibrated. Air bubbles are removed by floating the internal bubbles and the bubbles on the boundary surface with the inner wall of the formwork and releasing them to the outside. Then, the concrete in the mold is cured by steam curing for about 4 to 10 hours, for example.

JP-A-5-295789

However, high-strength concrete is higher in viscosity than fluid concrete (strength 21 to 36 N / mm ² ) even in a fluidized state before curing. For this reason, when manufacturing pillars, beams, etc., the concrete filled in the mold did not sufficiently float on the surface even when the concrete was vibrated. Moreover, high-strength concrete has a high viscosity and can only be finished for 4 to 5 hours or more, for example, 10 hours to 24 hours, and after the air bubbles remaining inside are sufficiently discharged to the outside. It was.
In this case, if the surface finish processing is performed before the air bubbles inside the concrete are discharged from the surface to the outside, then the bubbles rise and are discharged to the outside, so that a concave portion of a crepe-like bubble mark is formed on the concrete surface. There was a problem of being formed. In addition, the bubbles continue to rise little by little in the high-strength concrete over a long period of time, and there remains a problem that irregularities consisting of numerous bubble traces are formed on the surface.
For this reason, in order to produce a high-strength concrete product, curing for a long time is necessary until bubbles are not released, which is unsuitable for efficient production in a factory.

High-strength concrete has a very small W / C (water content in the concrete), so the surface that is the finished surface dries quickly, but the moisture content of the concrete underneath does not follow the surface drier. Wrinkles sometimes occurred.
In particular, pillars and beams made of high-strength concrete are not popular because the appearance of the surface where bubbles are released and the recesses of the bubble traces are exposed to the outside after being built in the field is poor. there were. For this reason, conventionally, it has been troublesome because the finishing surface is formed by filling the recesses and irregularities of the bubble marks by thinly applying finishing concrete, paint or the like to the concrete surface after completion of curing.

In order to eliminate the trouble of finishing the concrete surface, it has also been proposed to finish the surface by covering the concrete surface after placing the film sheet during curing. Since air bubbles will rise to the surface later, the surface finish in the area without air bubbles is good, but the problem of creating deep and large crevasse-like air bubble traces due to coalescence of air bubbles floating on the concrete surface Could not improve. In addition, there remains a problem such that air bubbles remain between the concrete surface and the film sheet and the film sheet swells up in a hill shape, and it is necessary to expel and remove the remaining air bubbles.
Therefore, even if the film sheet is coated on the surface after vibration is applied to the formwork on which high-strength concrete is placed, the surface finish is partially improved, but bubbles rise on the concrete surface for a long time. For this reason, it was not possible to eliminate a deep concave portion having a crepes shape on the surface. In addition, there was no change in that it took about 4 to 10 hours for the bubbles to rise and the precast concrete product to be completed.

In view of such circumstances, the present invention provides a method for producing a concrete product in which a concrete product is finished without forming a crevasse-like recess due to air bubble marks on the concrete surface, and a film sheet used in this method and The object is to provide a concrete product produced by the method.
Another object of the present invention is to provide a method for producing a concrete product that does not leave a creped-like recess due to bubble marks on the concrete surface and can finish the concrete product in a short time.

The method for producing a concrete product according to the present invention includes a step of placing concrete in a mold, a step of vibrating and deaerating the mold on which the concrete is placed, and a concrete surface exposed to the opening of the mold. And a step of covering a film sheet in which a plurality of small holes are formed at predetermined intervals, and air bubbles rising from the concrete are degassed through the small holes in the film sheet and cured to produce a concrete product. It is characterized by.
According to the present invention, the concrete placed in the mold is vibrated to degas the internal bubbles, and after curing, covering the film sheet with small holes on the concrete surface, Even if air bubbles inside the concrete rise to the surface, they are released individually as small bubbles from the small holes, so that the bubbles are released outside from the small holes in the state of small bubbles without coalescence and aggregation. No large crevasse-shaped recess is generated on the surface. In addition, a smooth and good finished surface is formed on the concrete surface where there are no small holes in the film sheet. Therefore, it is possible to finish a concrete surface that hardly requires finishing by the film sheet. Even when finishing, fine protrusions corresponding to small holes are formed on the concrete surface, but it corresponds to small holes compared to the case where the film sheet is not covered or the film sheet without holes is covered. Since there are only small protrusions, the concrete surface can be finished by a simpler finishing process.

In addition, the method for producing a concrete product according to the present invention includes a step in which a heater member is embedded inside the concrete surface in the mold to heat the concrete and harden it in layers before coating the film sheet. It is characterized by being added.
According to the present invention, the manufactured concrete product requires a long period of curing, and during that time bubbles rise, but if the heater member is embedded in the vicinity of the surface where the bubbles in the concrete rise and heated, the heater member The chemical reaction and curing by heat proceeds more than the front and back regions adjacent to the layer in which the layer is embedded, and bubbles rising from below can be contained to prevent the surface from rising and discharging. For this reason, bubbles rise only from the layer to the surface where curing has progressed by heating, so that the amount of bubbles is small and the rising is completed in a short time. Therefore, the time required for the bubbles to rise is shortened, so that the curing time can be shortened. Therefore, it is not necessary to perform finishing, and the concrete product can be manufactured in a short time, and the manufacturing efficiency is remarkably improved.
When the heater member is buried in concrete, an arbitrary structure such as a lattice may be adopted. However, when the heater member is taken out before the concrete is hardened, it is preferable to arrange and arrange linear heater members.

Further, a steam curing step is provided between the step of degassing the concrete in the mold by the vibration and the step of heating the concrete with the heater member.
Steam curing can promote the temperature rise and chemical reaction of concrete in the formwork.
Moreover, you may make it add the curing process which installed the curing mat containing a water | moisture content to the film sheet coat | covered on the concrete surface.
When the water content W / C is small, such as high-strength concrete, air bubbles are released from the surface through the small holes in the film sheet, and the surface tends to dry out from the inside. By supplying moisture from the mat through small holes in the film sheet, wrinkles on the concrete surface can be prevented.

The concrete deaeration film sheet according to the present invention has a plurality of small holes arranged at predetermined intervals, and discharges air bubbles floating from the inside of the concrete covered with the surface of the placed concrete to the outside through the small holes. Features.
If such a film sheet is used in a concrete product manufacturing method and covered with a film sheet before curing, bubbles floating from the inside of the concrete are released to the outside in a small dispersed state through small holes. Bubbles gather to form a crepe-shaped concave portion, and a convex portion of a small hole in the film sheet pressure is formed, but can be easily removed after curing. Since the concrete is hardened and formed on a smooth surface in the region without the small holes, the concrete product has a good finished surface.

A concrete product according to the present invention is a concrete product manufactured using any one of the above-described methods for manufacturing a concrete product, and the surface coated with the film sheet has air bubbles rising from the concrete before curing. A plurality of small hole projections discharged to the outside through the plurality of small holes of the film sheet and a smooth surface formed by the region of the film sheet without the small holes are formed.
According to the present invention, the concrete product is finished by covering the surface before curing with a film sheet in close contact so that air bubbles are discharged from a large number of small holes while being small and the surface without small holes becomes a smooth surface. Surface accuracy is improved.
In addition, the concrete product according to the present invention is characterized in that a hardened layer for enclosing air bubbles inside the concrete surface is formed before the region before and after the layer.
In a concrete product, air bubbles are sealed inside the hardened layer so as not to be discharged from the surface, so that there are few bubble marks formed on the surface, and the accuracy of the finished surface is good.

  The method for producing a concrete product according to the present invention covers a film sheet having small holes on the surface of the concrete after curing. Since it is discharged to the outside in a separated state, bubbles do not collect or bubble pools are formed, and no large crevasse-like recesses remain on the surface. Therefore, it is possible to manufacture a concrete product having a concrete surface that requires little finishing by the film sheet. In this case, air bubbles are discharged from the small holes, and fine convex portions corresponding to the small holes are formed on the concrete surface, but compared with the case where the film sheet is not covered or the film sheet without holes is covered, Since it is a small convex part corresponding to a small hole, finishing is not necessary. Even in the case of finishing, the concrete surface can be finished by a simple finishing process that removes small protrusions.

It is a concrete product manufactured with the manufacturing method of the concrete product by a first embodiment of the present invention, and is a perspective view showing the surface of high-strength concrete in a formwork in a state where curing is finished and a film sheet is removed. . It is a top view which shows the film sheet which perforated the small hole used by 1st embodiment of this invention by predetermined spacing. It is a flowchart which shows the manufacturing method of the concrete product by 1st embodiment of this invention. It is a figure which shows the process which laid high-strength concrete in the formwork used with the manufacturing method of the concrete product by 1st embodiment of this invention. It is a figure which shows the process which coat | covered the film sheet and the curing sheet on the surface of high-strength concrete. It is a flowchart which shows the manufacturing method of the concrete product by 2nd embodiment of this invention. In the manufacturing method of the concrete product by 2nd embodiment, it is a longitudinal cross-sectional view in the state where the heater electric wire was embed | buried under the surface inside of the concrete laid in the mold. It is a perspective view which shows the state which embedded the heater electric wire in the concrete in the mold shown in FIG. It is a figure which shows the curing process which covered the film sheet and the curing mat which formed the small hole in the surface of the high strength cement containing the layer which hardened with the heater electric wire.

Hereinafter, a manufacturing method of a high-strength concrete product, a film sheet, and a concrete product according to each embodiment of the present invention will be described with reference to the accompanying drawings.
First, the manufacturing method of the high-strength concrete product by 1st embodiment of this invention, the film sheet used for this, and a concrete product are demonstrated with reference to FIG. 1 thru | or FIG.
The high-strength concrete product manufactured according to the present embodiment is, for example, a pillar or beam having high strength used for high-rise apartments, high-rise buildings, etc., and is a precast concrete product manufactured in advance in a factory. In addition, the concrete product according to the present embodiment is not limited to columns and beams, but various concretes that require high strength properties such as segments used for tunnels, precast blocks used for approach sections of elevated roads in three-dimensional intersections, etc. Includes products.

High-strength concrete used for high-strength concrete products is concrete that is higher in strength than ordinary concrete and has been developed to realize high-rise buildings and large-span buildings. High-strength concrete is intended to set a target strength by blending cement, aggregate, water, admixture, etc., and the water-cement ratio: W / C is set smaller than that of ordinary ordinary concrete. High-strength concrete shall have a strength of 60 N / mm ² or more, for example. In the present embodiment, for example, a material having a strength of 100 N / mm ² or more is used.

FIG. 1 shows a film sheet 3 (see FIG. 2) on a surface 2a of a high-strength concrete 2 that is exposed to an opening of the mold 1 while being filled with high-strength concrete 2 in a box-shaped mold 1 and steam-cured. For example, a column 2A is shown in which the surface is finished by coating.
A film sheet 3 shown in FIG. 2 is a sheet made of synthetic resin such as polyprene for improving the finished surface of the surface 2a of the high-strength concrete 2, and has a large number of small holes 3a arranged in a zigzag pattern, for example. It has the structure which was made. The film sheet 3 is, for example, a sheet shape of length × width 900 mm × 900 mm, and a large number of small holes 3 a are about φ1.5 mm, for example, and are arranged in a staggered manner at intervals of 10 mm or less. In addition, the arrangement | sequence of the small holes 3a in the film sheet 3 is not limited to zigzag form, What is necessary is just to form and arrange | position at arbitrary fine intervals, such as a grid | lattice form and random form.

In the pillar 2A, which is a product of the high-strength concrete 2 obtained from the mold 1, no traces of air bubbles rising from the inside of the concrete are left on the side surface or the bottom surface in contact with the inner surface of the mold 1, and the mold 2 The traces of the small holes 3a of the coated film sheet 3 remain as small convex portions 4 on the surface 2a exposed from the openings. Therefore, as long as the surface 2a of the pillar 2A is constructed on a pillar such as a high-rise building and is not exposed to the outside, finishing of the surface 2a is not necessary. When the surface 2a is exposed to the outside, a finishing process may be performed by applying thin concrete, or the surface may be removed by polishing or cutting.
The PC pillar 2A, which is a concrete product according to the present embodiment, does not generate a crepe-shaped recess due to bubble marks on the surface 2a, but only a small protrusion 4 due to the discharge of bubbles from the small hole 3a of the film sheet 3. Therefore, finishing is not necessarily required.

Next, the concrete product manufacturing method according to the present embodiment will be described with reference to the flowchart shown in FIG.
First, the mold 1 shown in FIG. 4 has a rectangular parallelepiped volume of, for example, length × width × length 900 mm × 900 mm × 3000 mm. Then, the kneaded high-strength concrete 2 before curing is placed and filled in the mold 1 having the opening 1a formed in the upper portion (step 101). As the high-strength concrete 2, for example, a highly viscous material having a strength of 120 N / mm ² is used. Here, air is contained in the high-strength concrete 2 as air bubbles, and since the concrete has a high viscosity, the air bubbles are not released from the surface 2a in a short time like ordinary concrete, and take a long time. The bubbles gradually rise to the surface 2a and are released to the outside air.

In the next step, the high-strength concrete 2 is vibrated together with the mold 1 by a vibrator to forcibly raise the bubbles contained in the concrete 2 and release it to the outside (step 102).
In the third step, the high-strength concrete 2 filled in the mold 1 is steam-cured in high-temperature steam (step 103). Steam curing is performed for about 1 hour in a temperature environment of 50 ° C., for example. As a result, the high-strength concrete 2 is given an appropriate temperature and humidity to exert a chemical reaction and hardening of the concrete. Even at this stage, the bubbles P in the concrete 2 float on the surface 2a and are released. Steam curing for about 1 hour does not yet solidify the high-strength concrete 2 and release the bubbles P.

As the next step, the film sheet 3 with a large number of small holes 3a shown in FIG. 2 is coated on the surface 2a of the high-strength concrete 2 in the mold 1 (step 104). Further, a curing mat 5 containing moisture is placed on the film sheet 3 (step 105). In this state, curing is performed for 3 to 10 hours (step 106).
By covering the film sheet 3 in close contact with the surface 2a of the high-strength concrete 2, the air bubbles P that float from the high-strength concrete 2 escape to the outside as small air bubbles P through the small holes 3a formed in the film sheet 3. It becomes easy. Therefore, air bubbles P are merged between the concrete surface 2a and the film sheet 3 to form a convex curved or hill-shaped space in the film sheet 3, or a large crevasse-shaped recess in the surface 2a. There is no. In addition, it is not necessary to expel the gap where the bubbles P formed between the surface 2a of the concrete 2 and the conventional film sheet without holes are combined. And the surface 2a which contacts the film sheet 3 of the area | region without the small hole 3a becomes a smooth finished surface.

In this way, as the curing time elapses, the bubbles P rising from the inside of the high-strength concrete 2 can be smoothly and sufficiently discharged outside as small bubbles P through the small holes 3a of the film sheet 3. On the other hand, since the curing mat 5 placed on the film sheet 3 contains water, moisture is supplied to the surface 2a of the high-strength concrete 2 through the small holes 3a from which the bubbles P have been removed. Since drying is prevented, even if the water cement ratio W / C is small, it can be prevented that the surface 2a is first dried and wrinkled with respect to the inside of the high-strength concrete 2.
In addition, you may use hot water for the effect promotion as a water | moisture content included in the curing mat 5. FIG.
When the film sheet 3 is removed from the surface 2a of the high-strength concrete 2 after curing, the finished surface of the surface 2a is good and gloss is obtained in the region without the small holes 3a, but in the region of the traces of the small holes 3a, FIG. The convex part 4 as shown in FIG. In this case, since the convex part 4 is a small protrusion corresponding to the small hole 3a, the surface 2a where the convex part 4 remains can be used as a finished surface as it is. On the other hand, in order to form a better finished surface, a thin layer of concrete may be applied to the finished surface using a trowel or the like on the surface 4 where the convex portions 4 remain. Alternatively, the surface 2a including the convex portion 4 may be removed by being shallowly cut (step 107).

As described above, according to the method for producing a concrete product according to the first embodiment, the small air bubbles P are formed from the small holes 3a by covering the film sheet 3 with the small holes 3a in close contact with the surface 2a of the high-strength concrete 2. Can be released individually and sequentially to form the small convex portions 4 corresponding to the small holes 3a, and the finish of the surface 2a can be improved, and finishing can be eliminated.
Further, even if the surface 2a is finished, the processing by applying a thin layer and removing the convex portions 4 is simplified.
In addition, by covering the surface 2a of the high-strength concrete 2 with the film sheet 3 and covering the curing sheet 5 containing water, the air bubbles P are discharged from the small holes 3a to the outside, and a deep large concave portion in the form of a crepe is formed on the surface 2a. In addition, the moisture can be supplied from the curing sheet 5 to the small holes 3a, so that it is possible to prevent the surface 2a from being dried before the inside and generating wrinkles.

Next, the manufacturing method of the high strength concrete product by 2nd embodiment of this invention is demonstrated with reference to FIG. 6 thru | or FIG.
In the manufacturing method of the high-strength concrete product according to the first embodiment described above, since the film sheet 3 provided with the small holes 3a is used, the quality of the manufactured concrete product such as the pillar 2A is improved. The fact that it takes a long time for the air bubbles P to float and discharge in the high-strength concrete 2 is the same as the conventional manufacturing method. Therefore, in the method for producing a concrete product according to the second embodiment, an equivalent high-quality concrete product can be produced in a shorter time than the production method of the first embodiment.

The method for producing a concrete product according to the second embodiment is basically the same as the method for producing a concrete product such as the pillar 2A according to the first embodiment. Therefore, the same steps in the flowchart shown in FIG. 6 will be described using the same reference numerals.
First, the high-strength concrete 2 before hardening kneaded from the opening 1a is placed and filled in the mold 1 having the opening 1a formed in the upper portion shown in FIG. 4 (step 201). As the high-strength concrete 2, a high-strength and high-viscosity material such as 120 N / mm ² is used.
Next, as shown in FIGS. 7 and 8, a linear heater serving as a heater member at a depth of about 30 mm to 100 mm from the surface 2 a with respect to the high-strength concrete 2 filled in the opening 1 a of the mold 1. A plurality of electric wires 7 are embedded and arranged substantially in parallel (step 202). In this case, the heater wires 7 are preferably arranged at intervals of about 8 to 10 cm. Both ends of each heater wire 7 protrude outward from each frame portion of the mold 1.
Note that a plurality of other heater wires 7 may be embedded and arranged in a lattice shape in the direction intersecting the heater wires 7 at substantially the same depth in the high-strength concrete 2.
In this state, the surface 2a of the high-strength concrete 2 placed on the grid-like heater wire 7 is lightly finished.

In the next step, the high-strength concrete 2 is vibrated together with the mold 1 by a vibrator to forcibly raise the bubbles P contained in the concrete 2 and discharge them to the outside (step 203).
Then, the high-strength concrete 2 filled in the mold 1 is steam-cured in high-temperature steam, and the heater wires 7 are energized for 1 to 2 hours at a predetermined temperature, for example, about 34 ° C. to 75 ° C. Heat to a certain degree (step 204).
Steam curing is performed for about 1 hour in a temperature environment of 50 ° C., for example. As a result, an appropriate temperature and humidity are applied to the high-strength concrete 2 to exert the hardening power of the high-strength concrete 2. Even at this stage, the bubbles P in the high-strength concrete 2 float on the surface 2a and are released. In the case of steam curing for about 1 hour, the hardening of the high-strength concrete 2 and the release of bubbles P are not yet sufficient.
On the other hand, by heating the heater wire 7, the layer 8 in the depth region where the heater wire 7 is embedded in the high-strength concrete 2 is slightly lower than the temperature of the heater wire 7, for example, about 23 to 40 ° C. Heated (see FIG. 9). Thereby, in the area | region of the layer 8 of the high strength concrete 2 in which the heater electric wire 7 is arrange | positioned, temperature rises, a chemical reaction is accelerated | stimulated, and hardening will progress from an up-and-down (front and back) area | region.
Therefore, in the high-strength concrete 2 in the mold 1, the bubbles P that rise from the lower side of the layer 8 heated by the heater wire 7 stay in the layer 8 and are prevented from rising to the surface 2 a. Only the air bubbles P contained between the layer 8 and the surface 2a in the high-strength concrete 2 in the mold 1 can float on the surface 2a.

And when predetermined | prescribed 1-2 hours pass, the discharge | release of the bubble P is lose | eliminated, and hardening of the high strength concrete 2 advances, and when it will be in the state which can be finally finished, the heater electric wire 7 is made from the high strength concrete 2. Pull out (step 205). The heater wires 7 are arranged in one direction in the high-strength concrete 2 and the heater wires 7 are linear and separated from each other. Therefore, the heater wires 7 can be pulled out and taken out for each heater wire 7.
Next, the surface 2a of the high-strength concrete 2 after the heater wire 7 is pulled out is lightly finished to cover the surface 2a of the high-strength concrete 2 with the film sheet 3 with small holes 3a shown in FIG. 206). Further, as shown in FIG. 9, a curing mat 5 containing hot water is placed on the film sheet 3 (step 207). In this state, curing is performed for about 1 hour (step 208).
In the second embodiment, after steam curing, the layer 8 slightly heated from the top surface 2a of the block of high-strength concrete 2 in the mold 1 with the heater wire 7 is heated, so that the layer 8 is Curing progresses more than the upper and lower regions, and the viscosity increases. For this reason, most of the bubbles P in the high-strength concrete 2 below the layer 8 are sealed by the layer 8 to prevent the floating, so that only the bubbles P in the high-strength concrete 2 above the layer 8 are on the surface 2. Will surface. And the bubble P which floated on the surface 2 is discharge | released to the open air as the fine bubble P from the small hole 3a of the film sheet 3. FIG.

Therefore, the number of bubbles P released from the surface 2a of the high-strength concrete 2 is extremely small, and since the flying distance is short from the layer 8 to the surface 2a, the release of the bubbles P can be completed in a relatively short time. Even when the high-strength concrete 2 is highly viscous, the rising time of the bubbles P after the heating of the layer 8 by the heater wire 7 can be shortened. Therefore, the curing time for accelerating the hardening and rising the bubbles P is set to the conventional 4-10. The time can be reduced to about 1 hour.
Moreover, as in the first embodiment, the air bubbles P are merged between the concrete surface 2a and the film sheet 3 to form a convex curved space in the film sheet 3, or the surface 2a has a crepes-like recess. Will not form. And it is not necessary to expel the space | gap which the bubble P produced between the surface 2a of the concrete 2 and the conventional film sheet without a hole merged.

Further, since the curing mat 5 placed on the film sheet 3 contains water, moisture is supplied to the surface 2a of the high-strength concrete 2 through the small holes 3a from which the bubbles P have been removed, and the surface 2a is dried. Therefore, even if the water cement ratio W / C is small, it is possible to prevent the surface 2a from being dried first and wrinkled with respect to the inside of the high-strength concrete 2.
When the film sheet 3 is removed from the surface 2a of the high-strength concrete 2 after the curing is finished, the finished surface of the surface 2a is good and gloss is obtained in the region without the small holes 3a, and the region of the traces of the small holes 3a is shown in FIG. The convex part 4 as shown in 1 remains. In this case, since the amount of the bubbles P discharged outside is small even in the region where the small holes 3a are provided, the convex portions 4 formed by the bubble marks passing through the small holes 3a are further reduced, and the finished surface is further improved. Therefore, it is not necessary to finish.
In order to form the finished surface more satisfactorily, the finished surface is finished by applying a thin layer of concrete to the surface 2 where the convex portions 4 remain, using a trowel or the like, or by cutting and removing the convex portions 4. Also good.
In the second embodiment, during the production of the concrete product, the layer 8 which is a part of the high-strength concrete 2 filled in the mold 1 is hardened more than the others, but the other regions are obtained by the curing. However, since the curing proceeds, a concrete product with uniform strength can be obtained throughout.

  As described above, according to the method for producing a concrete product according to the second embodiment, in addition to the effects of the first embodiment, the air bubbles P floating on the surface 2a by the layer 8 formed in the vicinity of the surface 2a of the high-strength concrete 2 Therefore, when the pillar 2A is manufactured as a precast concrete product in a factory, for example, it can be manufactured in about 1 to 1.5 hours. Therefore, concrete products such as the pillars 2A, beams, and segments can be manufactured in a short time in a factory or the like, so that manufacturing efficiency can be significantly improved.

In each of the above-described embodiments, the method for producing a concrete product using high-strength concrete having a strength of 60 N / mm ² or more has been described. However, the present invention is not limited to the above-described high-strength concrete, and is not high-strength ordinary concrete. Needless to say, it can be used for various concrete products including.
For example, the present invention can be applied to a concrete product using a high fluidity concrete having a slump flow of 60 cm or more, for example, a tunnel segment manufactured by placing high fluidity concrete on a mold. Even after high-fluidity concrete is placed on the mold, even if it is vibrated by vibration, the bubbles contained in the high-fluidity concrete cannot be sufficiently removed, so the production method according to the present invention can be applied.

In addition, the concrete product obtained by the production method of the present invention is not limited to columns, beams, segments, etc., which are precast concrete products, and can be applied to various concrete products.
Further, the heater wire 7 is linearly embedded and disposed slightly below the surface 2a in the high-strength concrete 2 of the mold 1, but instead of this method, the high-strength concrete 2 is replaced with the mold 1 When placing in, it is filled to a position slightly lower (about 1 to 10 cm) than the height position of the surface 2a, and a plurality of heater wires 7 are placed and arranged on the upper surface, and then the height is increased on the upper surface. The strength concrete 2 may be placed in two stages so as to be refilled up to the height of the surface 2a and embedded in the heater wire 7.
Further, when the heater wire 7 is embedded in the high-strength concrete 2, it is not always necessary to install the heater wire 7 on the entire surface of the layer 8 of the high-strength concrete 2. For example, the heater wire 7 is divided into an appropriate number such as 1/2. The layer 8 may be formed by being embedded and sequentially heat-treated. In this case, the layer 8 does not need to form the same surface and may be shifted in the vertical direction.

In the second embodiment described above, the heater wire 7 used for heating the high-strength concrete is taken out from the high-strength concrete 2 before it is completely cured. Also good.
In this case, in the second embodiment, the heater electric wire 7 is arranged in a linear shape in order to take out the heater electric wire 7 from the high-strength concrete 2. Any arrangement configuration suitable for forming the layer 8 by heating the high-strength concrete 2 such as forming may be adopted.
Moreover, about the invention which heats some layers 8 in the high-strength concrete 2 using the heater electric wire 7 and advances hardening from another area | region and suppresses the raise of the bubble P by the layer 8, it necessarily coat | covers the film sheet 3. There is no need.

1 Form 2 High-strength concrete 2A Concrete product 2a Surface 3 Film sheet 3a Small hole 4 Recess 5 Curing sheet 7 Heater electric wire 8 Layer P Bubble

Claims (7)

Placing concrete in the formwork;
A step of vibrating and degassing the formwork on which the concrete is placed;
Covering the concrete surface exposed to the opening of the mold with a film sheet in which a plurality of small holes are formed at predetermined intervals,
A method for producing a concrete product, characterized in that air bubbles rising from the concrete are deaerated through a small hole in a film sheet and cured to produce a concrete product.   2. The production of a concrete product according to claim 1, wherein a step of adding a heater member to the inside of the concrete surface in the mold and heating the concrete to form a layer is added before the film sheet is coated. Method.   The method for producing a concrete product according to claim 1 or 2, wherein a steam curing step is provided between the step of degassing the concrete in the mold by the vibration and the step of heating the concrete.   The method for producing a concrete product according to any one of claims 1 to 3, wherein a curing process in which a curing mat containing moisture is installed is added to the film sheet coated on the concrete surface.   A concrete deaeration film sheet in which a plurality of small holes are arranged at predetermined intervals, and air bubbles floating from the inside of the concrete covering the surface of the cast concrete are discharged to the outside through the small holes.   A concrete product manufactured using the method for manufacturing a concrete product according to any one of claims 1 to 4, wherein air bubbles floating from inside the concrete before curing are formed on the surface coated with the film sheet. A concrete product in which convex portions of a plurality of small holes discharged to the outside through small holes in a sheet and a smooth surface formed by a region of a film sheet having no small holes are formed.   The concrete product according to claim 6, wherein a hardened layer for enclosing air bubbles in the concrete is formed inside the concrete surface on which the convex portions are formed before the other regions.

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