JPH10102773A - Wet curing device for concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a side wall and a surface of an arch part in a wet state by installing a porous conduit on a water-holding sheet making contact with a concrete surface and setting a presser means in a hollow inside of which gas is injected on a back surface of the water-holding sheet. SOLUTION: An air tube 2 is set to match with a sectional shape of a tunnel. Thereafter, the air tube 2 is bulged by putting air in it from an air introducing port 5 in this state. Thereby, the air tube 2 is bulged in a direction to push the tunnel section open by taking reaction force upward from a bottom surface as its both ends come to be in a state they are pressed on the tunnel bottom surface. Thereby, non-woven fabric 3 is adhered on both side walls and a secondary lining concrete surface of the arch part. Thereafter, water is burst out from a nozzle 6 of a porous conduit 4. Thereby, water is extensively permeated by capillarity between the inside of the non-woven fabric 3 and a part between the non-woven fabric 3 and a concrete surface or by dead weight, and wet curing is certainly carried out. Consequently, it is possible to maintain a wet state of the concrete surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete wet curing device for preventing dry cracks mainly occurring in tunnel lining concrete.

[0002]

2. Description of the Related Art In a mountain tunnel method, a shotcrete is applied to the ground while rock bolts are used together to prevent the excavated ground from loosening, and then a lining concrete is further applied on the shot concrete. In general, long-term stability of tunnels is intended.

[0003] In the construction of lining concrete, first, a formwork is installed at a predetermined position, and after confirming that a required winding thickness is secured, concrete is poured and the mold is formed when a certain strength is developed. Remove the frame.

[0004] Here, if the mold is left detached, moisture may evaporate from the exposed concrete surface and dry cracks may occur. For this reason, wet curing of the concrete surface is performed by a method such as watering or laying a water-absorbing curing mat to prevent dry cracks.

[0005]

However, there is a problem that water is evaporated from the side wall portion and the arch portion of the tunnel immediately after watering, and the film is immediately peeled off even when the curing mat is attached. Has occurred,
The only way to prevent dry cracks in such sites is to spray water frequently.

The present invention has been made in view of the above-mentioned circumstances, and provides a concrete moisture curing apparatus capable of maintaining a concrete surface in a wet state without frequently spraying water on a side wall or an arch. The purpose is to:

[0007]

In order to achieve the above object, a concrete wet curing apparatus according to the present invention comprises a water retaining sheet abutting on a concrete surface, a perforated water transmission pipe. At the same time, a holding means filled with a gas inside the hollow is installed on the back of the water retention sheet.

Further, in the concrete wet curing apparatus according to the present invention, the holding means is constituted by an air tube, and the air tube is formed in a horseshoe shape so that the side where the water retention sheet is disposed is outside. .

In the concrete wet curing apparatus according to the present invention, the pressing means takes a reaction force from an appropriate portion, for example, from the bottom of the tunnel or the opposite side wall of the tunnel, or from a supporter installed for the reaction force, and presses the pressing means on the concrete surface. Push into the side.

[0010] Then, the reaction force from the shoring works and the like is transmitted to the water retention sheet via the filling gas in the holding means, and the water retention sheet adheres almost uniformly to the concrete surface over a wide range. Therefore, if water is supplied to the water retention sheet through the perforated conduit in such a state, moisture is uniformly supplied to the entire concrete surface, and thus the concrete surface is
The wet condition is reliably maintained.

Here, when the holding means is constituted by an air tube, and the air tube is formed in a horseshoe shape such that the side where the water retention sheet is disposed is on the outside,
An air tube is set in the tunnel according to the cross-sectional shape of the tunnel, and in such a state, air is introduced into the tube and inflated.

Then, the air tube is in a state in which both ends thereof are pressed against the bottom surface of the tunnel, and the air tube expands in such a direction as to take up an upward reaction force from the bottom surface of the tunnel and expand the cross section of the tunnel. It fits tightly on the concrete surfaces of both sides of the tunnel and the arch.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a concrete wet curing apparatus according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall perspective view and a partially enlarged perspective view showing a concrete wet curing apparatus according to this embodiment. As can be seen from the figure, the concrete wet curing apparatus 1 according to the present embodiment is formed by curving an air tube 2 as a holding means so as to be substantially horseshoe-shaped and arranging a large number of the air tubes 2 so as to retain water on the outside thereof. The non-woven fabric 3 as a sheet is attached, and the air tube 2 and the non-woven fabric 3
And a perforated water pipe 4 is sandwiched between them.

The air tube 2 is adapted to take air in and out through an air inlet 5. The perforated water pipe 4 is provided with a large number of jet holes 6 so that water supplied from a pump (not shown) is jetted to the outside as shown by arrows.

In the concrete wet curing apparatus 1 according to the present embodiment, as shown in FIG.
Is installed so that its horseshoe shape matches the cross-sectional shape of the tunnel 11, and in this state, air is introduced from the air inlet 5 to inflate the air tube 2.

Then, the air tube 2 is in a state where both ends thereof are pressed against the tunnel bottom surface 14, and expands in a direction in which an upward reaction force is taken from the tunnel bottom surface to expand the tunnel cross section, and the nonwoven fabric 3 is expanded. Are pressed against the air tube 2 so that both side wall portions 12,
12 and closely adhere to the secondary lining concrete surface of the arch portion 13.

Next, in such a state, water is jetted from the jet holes 6 of the perforated water pipe 4.

[0019] In this case, the jet water is discharged from the nonwoven fabric 3.
Capillary action within and between the nonwoven fabric and the concrete surface,
Alternatively, the concrete surface is diffused and penetrated into a wide area by its own weight, and the concrete surface in close contact with the nonwoven fabric 3 is surely wet-cured.

As described above, according to the wet curing device for concrete according to the present embodiment, water is supplied to the nonwoven fabric 3 as a water retention sheet through the perforated water conduit 4, and the nonwoven fabric is supplied with water. Since the air tube 2 uniformly presses the concrete surface, the water from the perforated conduit 4 can be supplied to the concrete surface such as the tunnel arch portion and the side wall portion, and the non-woven fabric 3 is always in the concrete. Since it is in contact with the surface, the supplied water does not easily evaporate.

Therefore, the concrete surface at the above-described portion can be surely wet-cured, and cracks due to drying can be prevented.

Further, according to the present embodiment, since the air tube 2 serving as the holding means is formed in a horseshoe shape, it is possible to hold the nonwoven fabric 3 against the arch or the like by taking a reaction force from the bottom of the tunnel. There is no need to construct special supports.

In this embodiment, a nonwoven fabric is used as the water retention sheet. However, it is needless to say that another sheet having a water retention property, such as a normal cloth, may be used instead of the nonwoven fabric.

In the present embodiment, the perforated water pipe 4 is sandwiched between the nonwoven fabric 3 and the air tube 2. However, if the water jetted from the perforated water pipe is absorbed by the nonwoven fabric, the perforated water pipe 4 is perforated. The water pipe may be attached to any part of the nonwoven fabric. For example, it may be attached to the side that comes into contact with concrete, or as shown in FIG. 3, a perforated water pipe 4 may be buried between two nonwoven fabrics 3, 3.

According to these constructions, in addition to the above-described effects, there is no possibility that the water jetted from the perforated water pipe 4 falls without being absorbed by the non-woven fabric 3, and the water for curing is removed from the non-woven fabric 3. Also, there is an effect that it can be absorbed without waste.

Although not particularly mentioned in the present embodiment, it may be considered that the size of the air tube is smaller than the cross-sectional dimension of the tunnel, and the non-woven fabric cannot be pressed against the inner surface of the tunnel even when the tube is inflated. Can be In such a case, as shown in FIG. 4, a pair of elevating jigs 21 and 21 are installed at two places on the tunnel bottom surface 14, and both ends of the air tube 2 are placed on a receiving base 22 of the elevating jig 21. If the end is lifted, the air tube 2 can be pressed tightly against the inner surface of the tunnel even if the cross-sectional dimension of the tunnel is large.

If the lifting jig 21 is used, a sealed air tube through which air cannot enter or exit can be used as the holding means of the present invention.

In this embodiment, the air tube is formed in a horseshoe shape. However, the air tube need not necessarily be formed in a horseshoe shape, and may be formed in a straight shape as shown in FIG. In such a configuration, as shown in the figure, a support 31 is installed on the tunnel bottom surface 14, and the straight tube 32 is pressed against the concrete surface by taking a reaction force from the support 31. In such a configuration, the straight tube 32
Can bring the nonwoven fabric 3 into close contact with the concrete surface 12 and obtain the same effect as described above.

In this embodiment, the gas filled by the holding means is air. However, if a gas having a specific gravity lighter than air is filled instead, the tube rises in the air together with the gas filling. Therefore, in addition to the above-described effects, another effect that the installation work of the tube is facilitated is also achieved.

Further, in this embodiment, an example has been described in which the secondary lining concrete of the tunnel is used to prevent dry cracking, but it is needless to say that the present invention may be used for concrete structures other than the tunnel.

[0031]

As described above, in the concrete wet curing apparatus according to the present invention, the water holding sheet contacting the concrete surface is provided with the perforated water pipe, and the back of the water holding sheet is provided with gas inside the hollow. Is installed, so that the concrete surface can be kept wet without frequent spraying of water on the side walls and arches of tunnels and the like.

[0032]

[Brief description of the drawings]

FIG. 1 is a diagram of a wet curing device for concrete according to the present embodiment, wherein (a) is an overall perspective view and (b) is a partially enlarged perspective view.

FIG. 2 is a diagram showing a usage state of the concrete wet curing device according to the embodiment.

FIG. 3 is a cross-sectional view showing a modified example of a mounting position of a perforated water pipe.

FIG. 4 is a diagram showing another usage state of the wet curing device for concrete according to the embodiment.

FIG. 5 is a view showing a modified example regarding an air tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Moist curing apparatus of concrete 2 Air tube (holding means) 3 Nonwoven fabric (water retention sheet) 4 Perforated water pipe 32 Straight air tube (holding means)

Claims (2)

[Claims] 1. A wetting method for concrete, characterized in that a permeated water pipe is attached to a water retention sheet abutting on a concrete surface, and holding means filled with gas is installed in the back of the water retention sheet. Curing device. 2. The concrete wet curing apparatus according to claim 1, wherein the holding means is formed of an air tube, and the air tube is formed in a horseshoe shape such that a side on which the water retention sheet is disposed is outside.