JP3542977B2 - Method of manufacturing concrete products - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing various concrete products used for constructing a culvert (box culvert or the like), a fire prevention water tank, a common ditch, an underpass, or an assembled garage.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in the case of producing concrete cylindrical products such as box culverts by casting concrete, concrete products are produced by the following formwork and method in order to improve the finished condition of the bottom inner surface of the concrete products. It is known.
[0003]
That is, in the first manufacturing method, the mold is provided with holes at regular intervals in the inner mold at the bottom inner surface thereof and an air chamber which is a hollow frame. Use a cloth with tension applied. Then, concrete is cast in a state where the formwork is installed horizontally, and then the air chamber is continuously sucked by an air ejector driven by a compressor to remove air, excess moisture, and the like, thereby producing a concrete product.
[0004]
Further, in the second manufacturing method, the mold is provided with a water outlet at a constant interval in the inner mold on the bottom inner surface, and a hole provided with a perforated frame to which a filter cloth is applied with tension on the inner surface. use. After placing the formwork horizontally and placing concrete, compaction of concrete while exuding air and excess moisture from the inner surface of the bottom from the outlet using the internal static pressure due to the weight of uncured concrete. And a vacuum cleaner is used to suck up excess water or the like that has oozed out during the compacting operation and accumulated on the inner mold frame with a vacuum cleaner to produce a concrete product.
[0005]
[Problems to be solved by the invention]
However, in the former first manufacturing method, a dedicated air chamber is required for each of the inner molds on the bottom inner surface, and furthermore, the compressor must be operated continuously for a long time by setting an air ejector in this air chamber. It was not suitable for mass production, and construction was troublesome. In the latter second manufacturing method, when a certain amount of leaching water accumulates on the perforated frame, the leaching of more water is suppressed, and the removal of unnecessary air and excess moisture from the inner surface of the concrete product bottom is incomplete. It is easy to be.
[0006]
In addition, when the concrete product to be manufactured is a long product having a length of more than 2 meters, a manufacturing method in which the formwork is installed vertically and concrete is poured is conceivable. In this case, if the formwork is installed on the ground, the upper end of the formwork will be at a height of more than 2 meters, and it will be difficult to secure the work safety by performing the concrete placement work at that position. Therefore, equipment such as pits that are slightly shallower than the length of the formwork is provided so as to lower the casting work position, and work is performed by installing the formwork in the equipment. In such a construction method, excess water and the like emerges at the upper end side of the mold, so that it can be relatively easily discharged. The number of steps is increased as compared with the case where the mold is made horizontal, for example, the mold is taken out and the mold is removed in a state where the mold is horizontal, and as a result, the manufacturing cost is increased.
[0007]
An object of the present invention is to solve such a problem.
[0008]
[Means for Solving the Problems]
This application takes the following measures in order to achieve such an object. That is, a method of manufacturing a concrete product according to the invention of claim 1 of the present application is a method of manufacturing a concrete product by casting concrete in a formwork to manufacture a concrete product. And a plurality of grooves substantially parallel in the width direction of the formwork communicating with the outside of the formwork on the inner surface of the inner formwork that forms the bottom inner surface of the concrete product. Directly formingAt the same time, a compressor for generating airflow in the plurality of grooves from a substantially central portion in the longitudinal direction of the orthogonal grooves at one end of each of the plurality of grooves so as to communicate with each other by grooves orthogonal to each groove. To be able to connectWhen concrete is poured into a formwork in which a plate-like grooved form is provided in which a detachable filter cloth is stretched under tension and the form is arranged, the formwork is fixed in a longitudinal direction thereof. It is characterized in that at least air and excess moisture collected on the inner surface at the bottom by being inclined by the gradient are removed by passing through the filter cloth and leaching into the groove while compacting the concrete in the formwork.
[0009]
With such a configuration, when concrete is poured into the formwork, excess moisture and air that springs out of the uncured concrete at the portion corresponding to the inner surface of the bottom of the concrete product will pass through the filter cloth and form a groove. Intrudes into the groove of the frame. In this case, since the mold is inclined at a predetermined gradient in the longitudinal direction, excess moisture or the like leached into the groove flows toward the lower end of the mold, and the groove communicates with the outside of the mold. As a result, it is discharged outside the formwork. As described above, surplus moisture and the like that infiltrate into the groove via the filter cloth are sequentially and continuously discharged due to the inclination of the mold, so that the processing time can be reduced.
[0010]
In order to increase the efficiency of removing excess moisture and the like, at least in removing air and excess moisture, an airflow is passed through each groove of the grooved frame, and the air and excess moisture are removed by an airflow passing through the groove. Removal is preferred. As described above, by passing the airflow through the groove, the excess moisture or the like that has leaked into the groove is accelerated by the airflow, and the flow rate of the excess moisture or the like increases. Therefore, even if the amount of excess moisture or the like is large, the amount of discharge per unit time increases, and the processing time can be further shortened.
[0011]
Preferably, the formwork has a length of more than 2 meters and up to about 10 meters to facilitate manufacturing efficiency. Approximately 10 meters refers to a length that can be loaded on the longest trailer. Therefore, the length of the trailer may be set within the loading limit, and may be longer than 10 meters. Thus, even if the length of the mold is long, it is possible to efficiently manufacture a concrete product without reducing the efficiency of discharging excess moisture or the like because the mold is inclined. .
[0012]
In order to efficiently remove excess water, etc., the predetermined gradient is5% Is preferable. The predetermined gradient is preferably set at 0.1% to 2%. If the predetermined gradient is set to more than 5%, the poured concrete moves to a lower position in the formwork, that is, flows in the formwork, causing a problem that the concrete falls out of the formwork.
[0013]
In order to generate an even airflow in the groove and to simplify the structure, one end of each of the plurality of grooves is connected to a state where the airflow can pass, and the other end is opened. It is preferable that air flow can be generated in the groove from one connected end.
[0014]
Since the concrete product as described above is long, it is possible to construct a culvert or the like with a reduced number of joints, and it is possible to reduce the time required for joint work. In addition, since the number of joints can be reduced, the amount of members required for joining can be reduced. In addition, since the number of joints is reduced, construction is easy even in a long construction section, and it is possible to reduce problems such as water leakage from the joints.
[0015]
In addition, even if the length of the construction section is long, since the construction section is long, the number of used sections can be reduced, and the time required for loading and unloading during transportation can be reduced. Therefore, the use time of the heavy equipment can be shortened at the time of transportation and construction, and the loss on the heavy equipment can be reduced.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0017]
This embodiment shows a construction example of a box culvert BC having a product length of 4 meters, which is the concrete product shown in FIG.
[0018]
The formwork 100 of this embodiment is used when manufacturing a box culvert BC which is a concrete product. The box culvert BC has a length of, for example, 4 meters.
[0019]
As shown in FIG. 2, a mold 100 used in this embodiment is placed horizontally, and has an outer mold 1, an inner mold body 21, and a groove integrated with the inner mold body 21. It is composed of an inner mold frame 2 composed of an attached frame 22 and an end plate 1h (shown in FIG. 7) for closing both ends. The inner mold frame 2 is attached to the inside of the outer mold frame 1 with a space for forming the bottom plate BC1 and the side wall BC2 of the box culvert BC separated from the outer mold frame 1. The inner frame 2 is formed by combining an inner frame main body 21 and a grooved frame 22. The inner frame 2 has a structure that can be removed from a box culvert BC formed by disassembly or folding. The grooved frame 22 is made of a steel plate which is a magnetic material, and communicates with the outside of the mold frame 100 in substantially parallel with the bottom inner surface of the box culvert BC, that is, the inner surface of the bottom plate BC1 which is formed. A plurality of grooves 22a are provided for discharging air, excess moisture, and the like that spring during and after compaction to the outside. A filter cloth 23 is attached to the grooved frame 22 by applying tension while applying tension to the groove 22a.
[0020]
Specifically, as shown in FIGS. 3 to 5 (the mold 100 is shown in a horizontal state), the grooved frame 22 has a plurality of grooves 22a provided in parallel on its inner surface in the width direction. A hanging member 22b for hanging the grooved frame 22 and moving the grooved frame 22 inside and outside of the inner frame body 21 is provided on the outer surface thereof, and has a depth dimension longer than the product length of the box culvert BC. . The grooves 22a formed in the grooved frame 22 are formed at a predetermined pitch in the width direction of the inner mold frame 2, that is, in the width direction of the inside of the product of the box culvert BC, and have a length extending over the entire length of the grooved frame 22 in the depth direction. ing. The groove 22a has, for example, an isosceles triangle cross section.
[0021]
The grooved frame 22 has a guide wall 22c for guiding the filter cloth 23 at a portion facing the direction of tension applied to the filter cloth 23, that is, at both sides in the width direction. Further, the filter cloth 23 is attached to the grooved frame 22 so that the fixing position of the one edge 23a of the filter cloth 23 can be relatively changed, and the one edge 23a is detachably fixed. A plurality of engaging pillars 22d that engage with through holes 23b provided in one edge 23a of the filter cloth 23 are fixed to the mounting flange 22e at predetermined intervals, and the other edge 23c of the filter cloth 23 is A fixing flange 22f that is detachably fixed is provided to protrude from the guide wall 22c in the width direction of the grooved frame 22. The mounting flange 22e and the fixing flange 22f are respectively joined to the suspension member 22b.
[0022]
The engaging pillar 22d constitutes an engaging means together with the through hole 23b, and has, for example, two locking projections 22da and 22db for preventing the filter cloth 23 from falling off near the upper end thereof. When the filter cloth 23 is engaged, the locking projections 22da and 22db are provided apart from each other, and the fixing position of the filter cloth 23 can be changed by hooking the filter cloth 23 on one of them. ing. The fixing flange 22f is provided downward at an acute angle from the upper end of the guide wall 22c. Further, the grooved frame 22 has a length such that both ends thereof extend from the outer mold frame 1 in the product length direction of the box culvert BC when the outer mold frame 1 is assembled.
[0023]
As described above, since the grooved frame 22 is not provided with a through-hole for allowing air, surplus moisture, and the like to pass through, a decrease in mechanical strength can be suppressed, and thus durability can be improved. . Further, since the grooves 22a are provided at a predetermined pitch, even when cement paste or the like adheres, the adhered state inside the groove 22a can be easily visually checked with the filter cloth 23 removed. In addition, the time required for maintenance work can be reduced.
[0024]
As described above, the filter cloth 23 has the through-hole 23b at one edge 23a, and the plate-like magnet 23 that functions as a surface fixing member for fixing at the other edge 23c. 3 is detachably attached via a hook-and-loop fastener 4. The filter cloth 23 is attached to the inner surface of the grooved frame 22 under tension so as to close the groove 22a. The filter cloth 23 prevents passage of aggregates and other useful cement components in the concrete into the groove 22a, and selectively passes only those for the purpose of removing bubbles, surplus moisture, latencies, and the like. The air permeability or water permeability of the fiber is selected, and the mesh is adjusted. A female fastener 41 is fixed to the other edge 23 c of the filter cloth 23, and a male fastener 42 is fixed to the plate-shaped magnet 3. Accordingly, the plate-shaped magnet 3 is attached to a predetermined position of the filter cloth 23 by engaging the male fastener 42 with the female fastener 41. The plate-like magnet 3 has, for example, substantially the same length as the entire length in the length direction of the filter cloth 23. The plate-like magnet 3 may be one in which a plurality of plate-like magnets shorter than the entire length of the filter cloth 23 are attached at predetermined intervals. In this case, the length of the plate-shaped magnet 3 and the predetermined interval may be set so that the filter cloth 23 does not wrinkle or loose.
[0025]
In the above configuration, the filter cloth 23 is attached to the grooved frame 22 in the following procedure. First, the through hole 23b of one edge 23a of the filter cloth 23 is hung on the engaging column 22d with one of the locking projections 22da, 22db facing down. In the filter cloth 23 in which a part of the filter cloth 23 is being worn due to a plurality of attachments and detachments, the problematic portion is not overlapped with a corner or the like without using, for example, the locking projection 22db which has been used so far. , A locking projection 22da is used. As a result, the distance from the edge of one edge 23a of the filter cloth 23 to the corner when mounted is changed, so that a part of the filter cloth does not contact the corner at the same position as before. Similarly, when the grooved frame 22 is set in the inner frame main body 21, the relative position relationship with the inner frame main body 21 can be changed also for the portion that comes into contact with the inner frame main body 21. Therefore, the damage of the filter cloth 23 in those problem parts can be maintained in a slight state, and the durability can be improved. For this reason, it can be used for a long time, and is economically excellent.
[0026]
In this manner, after one edge 23a of the filter cloth 23 is engaged with the engaging column 22d, the filter cloth 23 is pulled along the inner surface of the grooved frame 22 while being pulled. In this case, the filter cloth 23 is sufficiently pulled so as not to wrinkle or loosen. Then, the other edge 23 c of the filter cloth 23, that is, the edge where the plate-shaped magnet 3 is attached by the hook-and-loop fastener 4 is brought to the fixing flange 22 f of the grooved frame 22. Then, the other edge 23c is pulled downward along the fixing flange 22f to apply tension to the filter cloth 23. The plate-shaped magnet 3 attached to the filter cloth 23 is placed on the fixing flange 22f in a state where tension is applied to the filter cloth 23 without loosening or wrinkling, and the other edge 23c of the filter cloth 23 is fixed by magnetic force.
[0027]
The other edge 23c of the filter cloth 23 is fixed by the magnetic force of the plate-shaped magnet 3 attracted to the grooved frame 22 made of a magnetic material in this manner. Can be fixed by the fixing work. If any looseness or wrinkles occur in the filter cloth 23, the position of the plate-shaped magnet 3 is moved to remove looseness or wrinkles. Even in this case, looseness and wrinkles can be removed only by changing the position of the plate-shaped magnet 3, so that the work can be facilitated.
[0028]
Further, in the filter cloth 23, since the plate-shaped magnet 3 is detachably attached to the filter cloth 23 by the hook-and-loop fastener 4, even if the filter cloth 23 becomes unusable before the plate-shaped magnet 3, Only the plate magnet 3 can be diverted to another filter cloth 23 or a new filter cloth 23. Therefore, the use efficiency can be increased without wasting the relatively expensive plate magnet 3.
[0029]
The grooved frame 22 to which the filter cloth 23 is attached is attached to the inner mold body 21 and discharges water or air that springs out of the cast concrete out of the mold. In the grooved frame 22, since the grooves 22a are formed at a predetermined pitch, the clogging of the filter cloth 23 and the grooves 22a that occur can be suppressed. Even if the groove 22a is clogged, the filter cloth 23 can be easily removed from the grooved frame 22 by removing the plate-shaped magnet 3 from the grooved frame 22, so that the cleaning of the groove 22a can be easily performed. can do.
[0030]
Hereinafter, production of the box culvert BC using the above-described mold 100 will be described with reference to FIGS. The formwork 100 is inclined to a predetermined gradient before concrete is poured, as will be described later. However, in FIGS. 6, 8 and 9, the configuration behind the end face is not shown. ing.
[0031]
First, the mold 100 is assembled on the base plate 6. In this case, as shown in FIG. 6, first, the outer mold 1 and the inner mold body 21 are assembled to form a required shape. That is, the inner frame 2 is set in a state where the grooved frame 22 for forming the inner surface of the bottom of the box culvert BC is removed and its mounting portion is set as an opening. In addition, both ends of the mold 100 are closed by the end plate 1h, and the upper side of the mold 100 is open.
[0032]
The corresponding end of the base plate 6 is lifted by, for example, a crane so that one end side in the longitudinal direction of the formwork 100 assembled in this manner is raised, and the end of the lifted end of the base plate 6 is A gap is formed on the lower surface side, and as shown in FIG. 6, a gradient member 7 having a thickness set corresponding to a predetermined gradient is inserted into the formed gap so that the mold 100 is inclined at a predetermined gradient. . The gradient member 7 may be, for example, a bar member having a wide bottom surface and a triangular cross section, or a square bar having a square cross section. The insertion position of such a gradient member 7 is the outermost position of the suspended end of the base plate 6. When the insertion position is closer to the center of the base plate 6, the gradient is slightly different, but there is no problem because it is within the set range. The predetermined gradient is set to 5% or less, and specifically, is set within a range of 0.1% to 2%. In the case of the form 100 for box culvert BC of 4 meters in this embodiment, when the predetermined slope is 1%, the height of the slope member 7 is about4It may be set to 0 mm. Then, in a state where the mold 100 is inclined in this manner, concrete is first driven into the bottom plate of the mold 100 in which the grooved frame 22 is not incorporated, and a portion in the mold 100 corresponding to the bottom of the box culvert BC Only enough concrete should be filled.
[0033]
The compounding of the concrete cement, each unit amount of water, and the water cement ratio used here is usually adjusted to the following range.
Cement: 300Kg / m^Three~ 500Kg / m^Three
Water; 110 l / m^Three~ 200 l / m^Three
Water cement ratio: 55% to 32%
Next, as shown in FIG. 8, a grooved frame 22 is arranged at a portion of the inner mold frame 2 having an opening, that is, at a portion where the bottom inner surface of the box culvert BC is formed, and is integrally connected to the inner mold body 21. I do. Specifically, the grooved frame 22 to which the filter cloth 23 is attached is installed in the inner mold main body 21 from above the inner mold main body 21. Then, in a state where the grooved frame 22 reaches a predetermined mounting position of the inner mold body 21, a portion extending from the outer mold frame 1 and placed on the angle member 1 a (FIG. 7) of the outer mold frame 1 is removed. After fixing, the grooved frame 22 and the inner frame body 21 are integrated. At the end of the grooved frame 22 that has been attached to the inner frame body 21, the end on the side where the gradient member 7 is inserted, that is, one end in the lifted state, penetrates into the groove 22 a of the grooved frame 22. A compressor (not shown) for generating pressurized air, which supplies a pressurized air flow into all the grooves 22a, is connected to discharge discharged air, excess moisture, and the like. The groove 22a and the compressor are compressed air without opening the groove 22a at the end of the grooved frame 22 extending from the outer mold frame 1 so that the pressurized air does not leak at the end of the groove 22a. Are connected in such a manner that they can be circulated.
[0034]
In this way, concrete is driven into the inside of the mold 100 in which the grooved frame 22 is integrated with the inner mold 2 from the gap between the outer mold 1 and the inner mold 2 as shown by arrows in FIG. Then, as shown in FIG. 9, concrete is sequentially poured into portions of the mold 100 corresponding to the block side walls and the top plate, and completely filled with concrete. During and after the driving, an external vibrator and an internal vibrator such as a rod-shaped vibrator to be inserted into concrete are operated to cause a compaction action by vibration, and a side wall or a top is formed on the bottom of the formwork 100. Excessive moisture in the uncured concrete is collected together with harmful components such as air bubbles and latencies on the inner surface of the bottom of the box culvert BC in contact with the grooved frame 22 due to the large compaction action of the concrete borne by the plate portion due to its own weight.
[0035]
The air, excess moisture, and the like are filtered by the filter cloth 23 by the static pressure in the mold 100 and leak into the grooves 22 a of the grooved frame 22. In this case, since the mold 100 is inclined by the gradient member 7, the excess moisture or the like that has leaked into the groove 22a is transferred to the other end opposite to the one end where the gradient member 7 is inserted by its own weight. Flowing towards. As described above, in a state where there is no airflow in the groove 22a, excess water or the like that has leaked into the groove 22a sequentially flows from the lower end of the groove 22a, and the water flow naturally flows in the groove 22a due to the gradient. Is what happens. This flow is accelerated by the airflow generated in the grooves 22a since the compressed air is sent from the compressor to the respective grooves 22a. Then, due to the synergistic effect of the flow due to its own weight and the airflow, the air, excess moisture, and the like in the groove 22a are efficiently discharged from the other end of the groove 22a. Further, since the air flow is formed in the groove 22a, the air pressure in the groove 22a decreases, and the air flows sequentially into the groove 22a through the filter cloth 23, but the collected air and excess moisture are compressed. Since the air is continuously supplied to each groove 22a, the air is discharged from the other open end of the groove 22a without being stored in the groove 22a. In this case, the excess moisture in the groove 22a flows sufficiently by its own weight, so that the pressure of the pressurized air for forming the air flow may be relatively low. By using such low-pressure pressurized air, it is possible to prevent the uncured concrete under the filter cloth 23 from being shaved by the pressurized air at the end where the pressurized air is supplied. it can.
[0036]
Thereafter, after the concrete has hardened, the gradient member 7 is pulled out from under the base plate 6 to bring the base plate 6 to a horizontal state. After the base plate 6 is returned to the horizontal state in this way, the outer mold frame 1 and the inner mold frame 2 are removed, and the mold removing operation is performed to manufacture the box culvert BC. Since the base plate 6 is horizontal when the mold is removed, the box culvert BC does not slip off from the base plate 6, and the work can be performed safely.
[0037]
As described above, since the concrete is cast by inclining the formwork 100, air, excess moisture, and the like leak into the grooves 22a formed at a predetermined pitch and move parallel to the surface of the concrete. Removed. In this case, the excess moisture or the like flows by its own weight toward the unlifted end of the formwork 100, and is accelerated by the air current generated in the groove 22a, so that the concrete product being manufactured is 4 meters or Even if it is longer than that, it is possible to discharge air, excess moisture, and the like generated from the concrete poured in a short time. Also, in order to make the length equivalent to such a long box culvert BC, compared to the case of combining a short box culvert BC, the man-hour for assembling the mold 100, the man-hour for applying the release agent, the man-hour required for demolding, It is possible to reduce the man-hours for casting. Therefore, the time required for manufacturing can be reduced, and the manufacturing cost can be reduced.
[0038]
Since the box culvert BC manufactured as described above is long, it is possible to construct a culvert or the like with a reduced number of joints, and it is possible to shorten the joining operation time and to make the members necessary for the joining. Can be reduced. As described above, the reduced number of joints facilitates construction even in a long construction section, and can reduce problems such as water leakage from the joints. In addition, even if the construction section is long, the length of one box culvert BC used is long, so that the number of used box culverts BC can be reduced, and the time required for loading and unloading during transportation is reduced. thingButit can. Therefore, during transportation and construction, the use time of the heavy equipment can be reduced, and the loss on the heavy equipment can be reduced.
[0039]
Note that the present invention is not limited to the embodiment described above.
[0040]
In the above embodiment, the base plate 6 is lifted before the concrete is cast, and the slope member 7 is inserted below the base plate 6 to incline the formwork 100. The slope member 7 may be fixed to the lower surface. In the case where such a gradient member 7 is fixed, for example, a gradient member set to have a predetermined gradient of 1% is fixed to the longest base plate for manufacturing a 10-meter concrete product. When a concrete product having a length of 10 meters or less is manufactured, the concrete product can be manufactured in a state where the form is inclined at a predetermined gradient by assembling the form on the base plate.
[0041]
The filter cloth 23 can be basically removed from the grooved frame 22 and may have any mounting structure as long as the filter cloth 23 can be mounted on the grooved frame 22 in a tensioned state. For example, the filter cloth 23 is tightly attached to the inner surface of the grooved frame 22, and both ends in the width direction of the filter cloth 23 are pulled in a direction approaching each other with an elastic rubber belt or the like, thereby attaching the filter cloth 23 with tension. Then, a filter cloth 23 can be removed by removing the rubber belt from both ends.
[0042]
In the above-described embodiment, the engagement pillar 22d is fixed to the mounting flange 22e. However, the engagement pillar 22d may be provided directly on the outer surface of the grooved frame 22. Further, instead of the engaging column 22d, an engaging projection that engages with the through hole 23b may be provided on the surface of the mounting flange 22e so as to be separated in the tension direction of the filter cloth 23. Further, a plurality of through holes 23b may be provided apart from each other in the tension direction of the filter cloth 23.
[0043]
Further, the plate-shaped magnet 3 may be removably attached to the filter cloth 23 by the hook-and-loop fastener 4 even without providing the engaging pillar 22d and instead at this side edge portion. That is, the plate-like magnet 3 is detachably attached to both side edges of the filter cloth 23. By attaching the plate-like magnet 3 to both side edges in this way, one edge portion does not become a fixed attachment position, so that even if the filter cloth 23 is elongated with the passage of time, tension is easily given to form a groove. It can be attached to the frame 22.
[0044]
Although the plate-shaped magnet 3 is described as being detachably attached to the filter cloth 23 by the hook-and-loop fastener 4, the strip-shaped hook-and-loop male member 41 is attached to the other edge 23c of the filter cloth 23, and on the other hand, a grooved frame is provided. A configuration may be adopted in which a female surface fastener 42 having a width greater than the male surface fastener 41 is fixed to the entire surface of the fixing flange 22f of the fixing member 22 with, for example, an adhesive. With this configuration, the male fastener 41 can be engaged with a desired position of the female fastener 42, so that the filter cloth 23 can be easily attached to the grooved frame 22. In this case, the other edge 23c of the filter cloth 23 is sewn into a tubular shape, and a rod serving as a core material is inserted into the sewn into the tubular shape, so that the other edge 23c is pulled substantially uniformly. It may be something to do. In addition, when the engaging means is realized by the surface fastener including the male surface fastener 41 and the surface fastener 42 described above, the surface fastener may be provided with a minimum length that does not cause wrinkles or looseness in the filter cloth 23. For example, a plurality of strip-shaped surface fastener male members 41 having a predetermined length may be attached to the filter cloth 23 at predetermined intervals.
[0045]
Further, the cross-sectional shape of the groove 22a may be trapezoidal, rectangular or semi-circular. Further, as a method of generating an airflow in the groove 22a, a method using depressurized air other than pressurized air may be used.
[0046]
Further, the plurality of grooves 22a are connected at one end thereof to a compressor or the like for generating an airflow from a substantially central portion in the longitudinal direction of the orthogonal grooves so that the grooves 22a communicate with each other by grooves orthogonal to each groove 22a. It may be one obtained.
[0047]
In addition, the configuration of each section is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.
[0048]
【The invention's effect】
As described above, according to the present invention, when concrete is poured into a formwork, excess moisture and air that springs from uncured concrete in a portion corresponding to the inner surface of the bottom of the concrete product are transmitted through the filter cloth to form a groove. The mold intrudes into the groove of the attached frame, but since the mold is inclined at a predetermined gradient in the longitudinal direction, excess moisture or the like that has leaked into the groove flows toward the lower end of the mold, and the groove is formed. By communicating with the outside of the frame, the surplus moisture and the like can be discharged to the outside of the mold. Therefore, surplus moisture and the like can be efficiently discharged without complicating the structure of the mold, and the time required for manufacturing a concrete product can be reduced.
[0049]
In addition, since the concrete product of the present invention is long, it is possible to construct a culvert or the like with a reduced number of joints, and it is possible to shorten the jointing time. In addition, since the number of joints can be reduced, the amount of members required for joining can be reduced. In addition, since the number of joints is reduced, construction is easy even in a long construction section, and problems such as water leakage from the joints can be reduced. In addition, even if the length of the construction section is long, since the construction section is long, the number of used sections can be reduced, and the time required for loading and unloading during transportation can be reduced. Therefore, during transportation and construction, the use time of the heavy equipment can be reduced, and the loss on the heavy equipment can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a box culvert according to an embodiment of the present invention.
FIG. 2 is a front sectional view showing the same embodiment in a horizontal state.
FIG. 3 is a perspective view showing a state in which a filter cloth is attached to a grooved frame constituting the inner mold of the embodiment.
FIG. 4 is a front view showing the main part of the inner mold frame of the embodiment.
FIG. 5 is an enlarged front view showing an attached state of the filter cloth of the embodiment.
FIG. 6 is an explanatory diagram showing a step of the method for manufacturing a box culvert according to the embodiment.
FIG. 7 is a side sectional view showing an inclined state of the formwork of the embodiment.
FIG. 8 is an explanatory diagram showing a step of the method for manufacturing a box culvert in the embodiment.
FIG. 9 is a process explanatory view showing the method for manufacturing the box culvert according to the embodiment.
[Explanation of symbols]
1 ... Outer formwork
2. Inner formwork
22… Groove frame
22a ... groove
23 ... Filter cloth

Claims (3)

A method for producing a concrete product by casting concrete into a formwork, comprising an outer formwork, and an inner formwork that is removably assembled with a space in the outer formwork, On the inner surface of the inner mold for molding the bottom inner surface of the concrete product, a plurality of grooves substantially parallel in the width direction of the mold communicating with the outside of the mold are directly formed, and each groove is formed at one end of each of the plurality of grooves. It is designed to be able to communicate with each other by orthogonal grooves, and to be able to connect a compressor for generating airflow in a plurality of grooves from a substantially central portion in the longitudinal direction of the orthogonal grooves, and to attach a detachable filter cloth. When concrete is poured into a formwork in which a plate-like grooved frame stretched under tension is arranged, the formwork is inclined at a predetermined gradient in the longitudinal direction and gathers on the bottom inner surface. Method for producing a concrete product, characterized in that the removal of air and excess water, and to the filter cloth is transmitted during compacting concrete in formwork is leaching into the groove even without. The method according to claim 1, wherein the formwork has a length of more than 2 meters and up to 10 meters. 3. The method according to claim 1, wherein the predetermined gradient is 5% or less.

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