JP6758135B2 - Processing method of joint surface - Google Patents

Description

The present invention relates to a method for treating a joint surface.

Conventionally, when constructing a large-scale concrete structure, the area for placing concrete is divided into a plurality of areas, and the entire concrete structure is constructed by sequentially connecting concrete through the joint surface. It is done.

Here, by forming irregularities on the surface of the joint surface, the adhesion between the existing concrete and the new concrete is strengthened. As an example, a curing retarder is applied to the joint surface, and then high-pressure water is sprayed to remove the latency and expose the uneven surface (see, for example, Patent Document 1). Here, the uneven surface means a surface having irregularities having a size of about several mm according to the size of the coarse aggregate of concrete.

JP-A-61-92261

However, in the method of removing latency using high-pressure water, a large amount of alkaline water is generated, which may contaminate surrounding rivers and dams. Therefore, it is desired to reduce the amount of waste water generated. Similarly, it is desired to efficiently remove the breathing water generated immediately after the concrete is placed.

Therefore, an object of the present invention is to provide a method for treating a joint surface capable of efficiently removing breathing water and latency in the joint of concrete through a horizontal joint surface.

The present invention is a method for treating a joint surface of a concrete structure to be joined in the vertical direction, wherein the joint surface of the placed concrete is covered with a water-absorbent sheet that adsorbs concrete-derived particles. In the covering step, the jointing surface is in contact with the water absorbing surface of the water absorbing sheet, and the covering step is performed at the time when breathing water is generated from the concrete, including a peeling step of peeling the water absorbing sheet from the joint surface. , Provide a method for processing a joint surface.

According to this treatment method, the water-absorbent sheet can absorb and retain the breathing water and adsorb the latency or the particles underlying the latency. Therefore, this should be applied at the time when the breathing water is generated from the concrete. With, breathing water and latency can be removed at the same time. Therefore, in the concrete jointing through the horizontal jointing surface, the amount of waste water generated can be suppressed to a small amount, and breathing water and latency can be efficiently removed.

In this treatment method, it is preferable that the covering step is performed so that the joint surface and the water-absorbent sheet have an uneven shape. In this case, the shear strength of the concrete structure can be significantly improved by forming irregularities on the joint surface.

The water-absorbent sheet may include a template having an uneven shape and a sheet body provided on one side of the template and having the water-absorbing surface. In this case, by pressing the water-absorbent sheet against the concrete, the uneven shape can be easily formed on the concrete surface, so that the workability is improved.

At this time, it is preferable that the template has a through hole in a portion other than the portion that becomes the bottom portion of the uneven shape in the covering step. If the water-absorbent sheet cannot completely absorb the breathing water, the overflowing water will flow through the through holes on the surface of the template and collect at the bottom. In the peeling step, the breathing water is removed together with the water-absorbent sheet. Therefore, a water-absorbent sheet having this template is particularly preferable when there is a large amount of breathing water.

The peeling step is preferably performed before starting the curing of the concrete. After peeling off the water-absorbent sheet, another curing sheet can be used during the curing period. Further, by performing the peeling step before the start of curing, it is possible to prevent the concrete from biting the water-absorbent sheet and hardening.

Further, the present invention is a method for treating a joint surface of a concrete structure to be joined in the vertical direction, which includes a covering step of covering the joint surface of the placed concrete with an impermeable sheet and an impermeable sheet. The covering step includes a peeling step of peeling the concrete from the joint surface, and the covering step is performed so that the joint surface comes into contact with the impermeable sheet and the joint surface and the impermeable sheet have an uneven shape. The covering step is performed at a time when breathing water is generated from the concrete, and the impermeable sheet provides a method for treating a joint surface having through holes in a portion other than the bottom portion of the uneven shape in the covering step.

According to this treatment method, the breathing water and the latency or the particles that are the basis of the latency contained in the breathing water overflow to the surface of the impermeable sheet through the through holes of the impermeable sheet, and the impermeable sheet. It will collect on the bottom of the uneven shape of. In the peeling step, these are removed together with the impermeable sheet. Therefore, by applying the impermeable sheet at the time when the breathing water is generated from the concrete, the breathing water and the latency can be removed at the same time. Therefore, in the concrete jointing through the horizontal jointing surface, the amount of waste water generated can be suppressed to a small amount, and breathing water and latency can be efficiently removed.

Also in this treatment method, it is preferable that the peeling step is performed before starting the curing of the concrete.

It is possible to provide a method for treating a joint surface capable of efficiently removing breathing water and latency in the jointing of concrete through a horizontal joint surface.

(A) is a cross-sectional view of the water-absorbent sheet according to the first embodiment. (B) is a figure which shows the processing method which concerns on 1st Embodiment. It is a figure which shows the processing method which concerns on 2nd Embodiment. It is sectional drawing of the water absorption sheet which concerns on 3rd Embodiment. (A) is a perspective view of the water-absorbent sheet according to the fourth embodiment. (B) is a cross-sectional view of the water-absorbent sheet according to the fourth embodiment. It is a figure which shows the action of the water absorption sheet which concerns on 4th Embodiment. (A) is a perspective view of the water-absorbent sheet according to the fifth embodiment. (B) is a cross-sectional view of the water-absorbent sheet according to the fifth embodiment. It is a figure which shows the action of the water absorption sheet which concerns on 5th Embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same parts or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

<First Embodiment>
As a first embodiment, a method of treating a joint surface using a water-absorbent sheet will be described. The water-absorbent sheet 1A shown in FIG. 1 (A) is a sheet made of a non-woven fabric. As the water-absorbent sheet 1A, one having water absorption and capable of adsorbing concrete-derived particles, particularly latency, is used. The water-absorbent sheet 1A is preferably an organic non-woven fabric having a positive charge that easily attracts a negatively charged latency electrostatically.

As shown in FIG. 1 (B), after placing the concrete 3 in the formwork 2, the surface of the concrete 3 is covered with the water-absorbent sheet 1A (covering step). The surface covered with the water-absorbent sheet 1A is the surface on which concrete is planned to be laid. This covering step is performed at a time when breathing water is generated from the concrete 3.

The generated breathing water is absorbed and held by the water absorbing sheet 1A. Excess breathing water collects on the surface of the water-absorbent sheet 1A. At the same time, the generated latency and the particles that form the basis of the latency are adsorbed on the water-absorbent sheet 1A. Here, "adsorption" is a concept including that particles are physically entangled with the water-absorbent sheet 1A, electrostatically attracted, and the like.

The water-absorbent sheet 1A is peeled off from the joint surface (peeling step) when the breathing water is sufficiently discharged. After that, the concrete curing period begins. During the curing period, it is preferable to use another curing sheet for curing while increasing water retention.

Here, as a judgment of the time when the breathing ends, for example, the correlation between the N-type penetration resistance value obtained in the N-type penetration test and the coagulation characteristic obtained in the coagulation test is investigated in advance, and the N-type of concrete 3 is determined. This can be done by confirming the first condensation from the penetration resistance value.

According to this method of treating the joint surface, the water-absorbent sheet 1A can absorb and retain the breathing water and adsorb the latency or the particles that are the basis of the latency, so that the breathing water and the latency are removed at the same time. be able to. Therefore, in the concrete jointing through the horizontal jointing surface, the amount of waste water generated can be suppressed to a small amount, and breathing water and latency can be efficiently removed.

Further, conventionally, a curing retarder may be used to remove the latency, but according to the treatment method of the present embodiment, the latency can be removed together with breathing water, so that it is not always necessary to use the curing retarder. Absent.

Further, by performing the peeling step before the start of curing, it is possible to prevent the concrete 3 from biting the water-absorbent sheet 1A and hardening.

<Second embodiment>
As a second embodiment, a method of treating the joint surface using another water-absorbent sheet will be described. As shown in FIG. 2, the difference from the first embodiment is that when the concrete 3 is covered with the water-absorbent sheet 1B, the joint surface and the water-absorbent sheet 1B are covered so as to have an uneven shape in cross section. Is.

After placing the concrete 3, the surface of the concrete 3 to be the joint surface is dug by running a plurality of parallel grooves in parallel using a rake, a trowel, etc., and unevenness is formed so as to have a zigzag cross-sectional view. .. The depth of the groove is about 2 to 3 cm. At this time, the direction in which the groove extends is preferably a direction orthogonal to the water path of the water that infiltrates the concrete structure after completion. In FIG. 2, it is assumed that water can infiltrate in the left-right direction shown. Then, the water-absorbent sheet 1B is brought into close contact so as to follow the uneven shape.

As another method, the surface of the water-absorbent sheet 1B and the surface of the concrete 3 may be formed at the same time by first covering the surface of the concrete 3 with the water-absorbent sheet 1B and pressing the surface of the concrete 3 with a trowel or the like.

According to this treatment method, the same effect as that of the first embodiment is obtained, and since the joint surface is formed with an uneven shape in centimeter units, the concrete 3 and the concrete 3 are joined to the concrete 3. Adhesion with concrete is improved, and the shear strength of the concrete structure after completion can be significantly improved. Further, when the direction in which the groove extends is orthogonal to the water path of the water entering the concrete structure, the water stopping property is also improved.

Further, even when the latency cannot be sufficiently removed only by the peeling process, the convex portion formed on the joint surface is a weak part in the structure, so that the latency remaining in the portion is small. It can be removed with energy and contributes to labor saving.

<Third embodiment>
As a third embodiment, a method of treating the joint surface using another water-absorbent sheet will be described. The difference from the second embodiment is that, as shown in FIG. 3, the water-absorbent sheet 1C includes a sheet body 11a (1A) having water absorption and a template 11b having an uneven shape. is there.

The template 11b is a folding screen-shaped plate made of rigid metal or resin, and has a zigzag shape in a cross-sectional view. A sheet body 11a is provided so as to line the template 11b.

The sheet body 11a, which is the water absorbing surface, is turned downward so as to come into contact with the concrete 3 to cover the concrete 3. At this time, since the template 11b has rigidity, it is not necessary to form a groove on the concrete surface in advance, and by pressing the water-absorbent sheet 1C against the concrete 3, an uneven shape can be easily formed on the concrete surface. Can be formed. Therefore, according to this processing method, workability is improved.

<Fourth Embodiment>
As a fourth embodiment, a method of treating the joint surface using another water-absorbent sheet will be described. The difference from the third embodiment is that, as shown in FIGS. 4A and 4B, the template 11c in the water-absorbent sheet 1D has a large number of through holes 11d.

The template 11c has a plurality of through holes 11d at the top of a portion of the water-absorbent sheet 1D that becomes a convex portion when viewed from the template 11c side. As shown in FIG. 4A, in each convex portion, a plurality of through holes 11d are provided at equal intervals in the direction in which the convex portion extends.

Even when this water-absorbent sheet 1D is used, the uneven shape can be easily formed on the concrete surface by pressing the water-absorbent sheet 1D against the placed concrete 3.

The through hole 11d is useful when the sheet body 11a has too much breathing water to absorb. That is, as shown in FIG. 5, when the breathing water W exceeds the water absorption limit of the water absorption sheet 1D, the breathing water W springs up from the through hole 11d and flows on the surface of the template 11c, and the template. It will accumulate on the bottom 11e of the unevenness of 11c. In the peeling step, the breathing water W is removed together with the water-absorbent sheet 1D. Therefore, the water-absorbent sheet 1D having the template 11c is particularly preferable when there is a large amount of breathing water.

Although FIG. 4 shows an embodiment in which the through hole 11d is provided at the top of the convex portion of the template 11c, the through hole 11d does not necessarily have to be provided at the top, except for the portion that becomes the bottom 11e. It suffices if it is provided in the portion.

<Fifth Embodiment>
As a fifth embodiment, a method for treating the joint surface using the impermeable sheet will be described. As shown in FIGS. 6A and 6B, the impermeable sheet 1E is a folding screen-shaped plate made of a rigid metal or resin, and has a zigzag shape in a cross-sectional view. .. The height difference between the top and bottom of the zigzag is about 2 to 3 cm.

The impermeable sheet 1E has a plurality of through holes 11d at the top of a portion that becomes a convex portion when viewed from one surface side. No through hole is provided in the bottom portion when viewed from the same side. As shown in FIG. 6A, in each convex portion, a plurality of through holes 11d are provided at equal intervals in the direction in which the convex portion extends.

At the time of use, the concrete 3 is covered with the surface of the cast concrete 3 so that the convex portion provided with the through hole 11d is at a high position (covering step). At this time, since the impermeable sheet 1E has rigidity, it is not necessary to form a groove on the concrete surface in advance, and by pressing the impermeable sheet 1E against the concrete 3, the impermeable sheet 1E can be easily pressed against the concrete surface. An uneven shape can be formed. The surface covered with the impermeable sheet 1E is the surface on which concrete is planned to be laid. This covering process is performed when breathing water is generated from the concrete.

As shown in FIG. 7, the generated breathing water W and the latency or the particles underlying the latency overflow through the through hole 11d to the surface of the impermeable sheet 1E and collect in the bottom 11e of the impermeable sheet 1E. ..

The impermeable sheet 1E is peeled off from the joint surface (peeling step) when the breathing water W is sufficiently discharged. After that, the concrete curing period begins. During the curing period, it is preferable to use another curing sheet for curing while increasing water retention.

According to this treatment method, the breathing water W and the latency or the particles which are the basis of the latency contained in the breathing water W overflow to the surface of the impermeable sheet through the through holes 11d of the impermeable sheet 1E. It will accumulate on the uneven bottom portion 11e of the impermeable sheet 1E. In the peeling step, these are removed together with the impermeable sheet 1E. Therefore, the breathing water W and the latency can be removed at the same time. Therefore, in the concrete jointing through the horizontal jointing surface, the amount of waste water generated can be suppressed to a small amount, and breathing water and latency can be efficiently removed.

In the above embodiment, the impermeable sheet has a rigidity, but a flexible sheet having no rigidity may be used. In this case, a rake, a trowel, or the like may be used to dig a plurality of parallel grooves on the surface of the concrete in parallel to make irregularities so as to have a zigzag cross-sectional view, and then cover the concrete surface with an impermeable sheet. .. Alternatively, as another method, the surface of the concrete may be covered with a flexible impermeable sheet first, and then pressed with a trowel or the like to form an uneven shape.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the fifth embodiment, the impermeable sheet is made of a single material having rigidity. As the impermeable sheet, the impermeable sheet 1E is made of a flexible material. , And this may be attached to the template 11c used in the fourth embodiment.

Further, in the above embodiment, the water-absorbent sheet or the impermeable sheet is peeled off before entering the curing period, but in some cases, the water-absorbent sheet or the impermeable sheet may be left laid even during the curing period. You may.

1A, 1B, 1C, 1D ... water-absorbent sheet, 1E ... impermeable sheet, 2 ... concrete formwork, 3 ... concrete, 11a ... sheet body, 11b, 11c ... template, 11d ... through hole, 11e ... bottom, W ... Breathing water.

Claims (3)

It is a method of treating the joint surface of a concrete structure that is connected in the vertical direction.
A step of covering the joint surface of the placed concrete with a water-absorbent sheet that adsorbs the particles derived from the concrete, and
Including a peeling step of peeling the water-absorbent sheet from the joint surface.
In the covering step, the joint surface is in contact with the water absorption surface of the water absorption sheet.
The covering step is performed at a time when breathing water is generated from the concrete, and the joint surface and the water-absorbent sheet are formed to have an uneven shape.
The water-absorbent sheet is a method for treating a joint surface, comprising a template having an uneven shape and a sheet body provided on one surface of the template and having the water-absorbing surface. The method for treating a joint surface according to claim 1, wherein the template has a through hole in a portion other than the portion that becomes the bottom portion of the uneven shape in the covering step. The method for treating a joint surface according to claim 1 or 2, wherein the peeling step is performed before starting the curing of the concrete.

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