JP3229262B2 - Method for exposing, reinforcing, repairing, and removing expansive agent of existing concrete buildings covered with mortar layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of exposing a skeleton covered with a mortar layer of an existing concrete building, and removing an expanding agent used to crush the mortar so as to expose the skeleton. A method, a method for reinforcing the building, and a method for repairing the building.

[0002]

2. Description of the Related Art Conventionally, as a decorative material or a tile, which covers a frame such as a pillar or a wall of an existing concrete building,
After the mortar layer as a base material for wallpaper etc. is renewed due to aging, seismic reinforcement of the building, repair of the building, etc., the mortar layer is removed from the skeleton to expose the skeleton, and then the skeleton is exposed. Is covered with a new mortar layer and a concrete layer.

In order to crush the mortar layer covering the skeleton, the mortar layer is provided with a plurality of holes penetrating therethrough, each hole is filled with an expanding agent, and the mortar layer is crushed from the skeleton. It is conceivable to do this by removing the pieces. The swelling agent filled in each hole exerts an expansion pressure on the peripheral wall surface of each hole due to the volume expansion over time, causing a large number of cracks in the portions between the holes, and separating the portions from the frame. Make

According to this, the crushing action of the mortar layer by the swelling agent proceeds gradually with little noise and almost no vibration. For this reason, without causing mental or physical distress to residents and users of the building in operation, and without affecting the operation and operation of precision equipment and facilities in the building, The skeleton can be exposed.

[0005] The mortar layer to be removed is not actually uniform in thickness, but includes a thick portion and a thin portion. For this reason, among the holes penetrating the mortar layer, there are holes extending further into the inside of the skeleton through the mortar layer, that is, holes reaching the inside of the skeleton, and the holes filled in such holes are provided. The swelling agent remains on the skeleton after removal of the mortar layer.

The swelling agent, by its nature, continuously expands in the presence of moisture, so that the mortar layer is renewed, the building is reinforced, and the building is repaired while the swelling agent remains in the skeleton. When covering the skeleton with new mortar, concrete, etc. for the expansion action of the expanding agent,
There is a possibility that crushing of a part of the skeleton and separation between the skeleton and the new mortar or concrete layer accompanying the crushing may occur.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to expose an existing concrete building without leaving an expanding agent used for crushing a mortar layer covering the building of the concrete building in the building. It is to provide a way to do it.
Another object of the present invention is to provide a method for removing the swelling agent.

Still another object of the present invention is to provide a method for reinforcing the body without leaving the expanding agent in the body and a method for repairing the body.

[0009]

According to the present invention, in order to expose a skeleton of an existing concrete building covered with a mortar layer, an expanding agent is provided in a plurality of holes provided in the mortar layer and penetrating therethrough. Is filled, and the mortar layer is crushed by volume expansion of the swelling agent over time, and after crushed pieces of the mortar layer are removed from the skeleton, the mortar layer remains in the hole reaching the inside of the skeleton among the plurality of holes. The swelling agent is removed.
The formation of the holes can be performed by subjecting the mortar layer to ultrasonic cutting. The removal of the swelling agent remaining in the hole reaching the skeleton is performed by spraying a large number of fine particles on this, or by rubbing with a wire brush, or by digging out a part of the skeleton that defines the hole reaching the skeleton. Can be performed.

[0010] The present invention also relates to a method of reinforcing and repairing the existing concrete building, wherein after exposing the frame, the frame is further covered with a reinforcing material and a new mortar layer.

[0011]

According to the present invention, the mortar layer covering the building is crushed, and the mortar layer is crushed by removing the crushed pieces and opening the hole on the surface of the building to crush the mortar layer. By removing the used swelling agent, a skeleton in which the swelling agent does not remain can be exposed. Also, by covering the skeleton with a new layer of concrete or mortar to reinforce the skeleton where the expanding agent does not remain, or by covering the skeleton with a new mortar layer to repair the skeleton. In the case where the expanding agent remains, it is possible to avoid breakage of the skeleton due to the expansion action of the remaining expanding agent, and separation of the skeleton from the new concrete layer or mortar layer, whereby the reinforcement and The repair can be completed.

Further, when the ultrasonic cutting method is applied to the formation of the hole filled with the expanding agent, the generation of noise and vibration accompanying the formation of the hole can be suppressed to a very low level. The swelling agent remaining in the hole reaching the skeleton has a peeling action or a shaving action of a large number of fine particles,
Alternatively, it can be completely removed by exerting a scraping action of a wire brush or by hollowing out the expanding agent together with a part of the frame.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a concrete skeleton 12 composed of pillars and walls forming a part of an existing concrete building 10 (only a part thereof is shown).
To remove the mortar layer 14 covering FIG. 2 (FIG. 2), the mortar layer 14 is provided with a plurality of holes 16 therethrough.

The mortar layer 14 is used for renewal or renewal due to its aging, or for seismic reinforcement described later.
Alternatively, it is removed from the frame 12 for repair.

The thickness of the mortar layer 14 applied to the surface of the frame 12 is not constant, and has a thin portion and a thick portion. Further, it is practically impossible to accurately measure the thickness of the mortar layer 14. Therefore, the hole 16 extending from the surface of the mortar layer 14 toward the skeleton 12 is formed by uniformly piercing the mortar layer 14 at a preset depth. Therefore, the hole 16 penetrating the thin portion of the mortar layer 14 reaches the inside of the frame 12. That is, a portion 18 (FIG. 2) of the hole 16 extends from the surface of the frame 12 toward the inside thereof.

The holes 16 can be formed all at once or sequentially at portions where the mortar layer 14 is to be removed. Further, the plurality of holes 16 are formed in consideration of a range or a distance limit to which the inflation pressure of the inflation agent 20 is effective, that is, a range or a distance limit in which a crack may occur, as described later. The interval, size, etc. can be set.

The holes 16 can be formed by subjecting the mortar layer 14 to ultrasonic cutting. That is, a spindle having a tip provided with a grindstone is rotated around its axis to apply the cutting force of the grindstone to the mortar layer 14, and the spindle is ultrasonically vibrated during this time to form the spindle. be able to.

The direction in which the ultrasonic vibration is applied is the axial direction of the spindle. The frequency and amplitude of the ultrasonic wave at this time are set to, for example, 20 kHz and 55 μm, respectively. By the application of the ultrasonic vibration, the cutting resistance of the grinding wheel is greatly reduced, so that the noise level and the vibration generated when the hole 16 is formed are extremely small. In particular,
At a distance of several meters, the cutting sound or the grinding sound is inaudible and almost vibration-free.

As a device for forming the hole 16, for example, a "hand-held rotary tool" described in Japanese Utility Model Registration No. 3019063 can be used. In this tool, a horn is attached to a tip of an ultrasonic vibrator rotatably supported in an outer case, and a grindstone is attached to a tip of the horn. When the ultrasonic vibrator is driven to rotate around its axis, the horn and the grindstone rotate around these axes. Further, by operating the ultrasonic vibrator, ultrasonic vibration can be generated in the axial direction of the horn. By pressing the whetstone against the surface of the mortar layer 14 to rotate the whetstone and apply ultrasonic vibration to the whetstone, almost no noise and vibration are generated.
A hole 16 can be formed. Of course, it is also possible to form the holes 16 using a device such as a drilling without ultrasonic vibration, for example, a diamond core drill.

After the holes 16 are formed, each hole is filled with a swelling agent 20. The swelling agent 20 is preferably a mixture of water and a drug mainly composed of an inorganic compound mainly composed of quicklime and silicate (for example, “Blystar” manufactured by Onoda Co., Ltd.) Reacts with water (hydration reaction) so that its volume expands with time.

Other examples of the expanding agent include those of calcined dolomite, magnesia, ordinary Portland cement-blast furnace slag-bauxite-gypsum, alumina cement-lime-gypsum, and the like.

Due to the volume expansion of the expanding agent 20 in each hole 16 over time, the peripheral wall surface of each hole 16 receives an expansion pressure in a direction (radial direction) perpendicular to this. Due to this inflation pressure, a portion between the holes 16 of the mortar layer 14 rises, and a number of cracks (not shown) are formed in the portion from one hole 16 to the other hole 16 opposed thereto. As a result, the mortar layer 14 is crushed and peels off from the surface of the frame 12.

Since the volume expansion of the expanding agent 20 in each hole 16 progresses slowly and almost without vibration, the mortar layer 14 can be crushed gently and almost without vibration. Therefore, during this time, building 1
0 does not cause mental or physical distress due to noise or vibration to residents and users of the building even when the building is in service, and does not operate or operate precision equipment or facilities in the building. An adverse effect on operation can be avoided.

Thereafter, a portion surrounded by the crack, that is, a crushed piece of the mortar layer 14 is removed from the surface of the frame 12. The removal of the crushed pieces is completed by waiting for natural crushing of the crushed pieces from the surface of the frame 12, or by applying a relatively small external force to the crushed pieces and dropping them.

As shown in FIG. 2, after the crushed pieces of the mortar layer 14 have been removed, an opening is formed on the surface of the
Part of the hole filled with 0 (hereinafter simply referred to as “hole”)
18 appears. The actual depth of the hole 18 is about 1-2 mm, and the expanding agent 20 that has substantially stopped expanding in the hole 18 is usually in a dry state and presents a powder.
This powder has the ability to expand again in the presence of moisture or in the presence of moisture in a mortar or concrete layer that is newly provided for the renewal, seismic reinforcement, repair, etc. of the mortar 14. Thus, the swelling agent 20 is then removed from the holes 18 according to the present invention, thereby completing the exposure of the skeleton 12.

The powdery expanding agent 20 in the hole 18 is
It can be removed by spraying a large number of fine particles using compressed air as a carrier medium. According to this, the collision of the fine particles with the air against the expanding agent 20 causes the expanding agent 20
Is scraped off and blown away from the frame 12, and is completely removed from the hole 18 (see FIG. 3). It is desirable to collect the scraped expanding agent 20.

As the fine particles, those made of sand, calcium bicarbonate or the like can be used. In particular, since the calcium bicarbonate is of the same quality as one component of the concrete, even if it may remain in the
2 does not harm and is relatively lightweight (specific gravity: 1.2
Because of 3), there are advantages such as easy recovery together with the compressed air.

An example of the particle size of the fine particles made of calcium bicarbonate can be set to 300 μm. Further, the blowing pressure of the compressed air, that is, the injection pressure and the injection amount when using the fine particles can be set to, for example, 5 kg / cm ² and 4001 / min, respectively.

Removal of the swelling agent 20 in the hole 18 can also be accomplished by scraping it with a manual or electric wire brush (not shown). Alternatively, the swelling agent 20 can be removed by piercing the swelling agent 20 through the hole 18 using a sharp tool such as a pick.

Alternatively, the swelling agent 20 can be removed from the frame 12 by digging out a concrete portion defining the hole 18. The concrete portion includes a hole 22 (FIG. 2) coaxial with the hole 18 and having a larger diameter than the hole 18 and a depth greater than the hole 18.
By drilling into the hole, it can be substantially dug out. The hole 22 can also be drilled with almost no noise and almost no vibration by applying the ultrasonic cutting to the body 12, or by using the diamond core drill.

After the swelling agent 20 has been removed, mortar is sprayed on the opening surface of the hole 18, painted, or disposed at a distance from the opening surface to define a space between the opening surface and the mortar. By casting in a mold (not shown), a new mortar layer 24 that fills each hole 18 and covers the opening surface (the surface of the frame 12) can be formed (FIG. 4).

As a result, the old mortar layer 14 is renewed or repaired with the mortar layer 24. Further, the new mortar layer 24 is a decorative plate (not shown) for renewal or, as shown in FIG. 5, a base layer for a later-described reinforcing material for earthquake-resistant reinforcement. New mortar layer 24
Is set to an appropriate or desired thickness dimension according to its use.

In the above seismic reinforcement, a new mortar layer 2
FRP sheet 26, which is a reinforcing material, is attached to cover 4 (for example, when frame 12 is a wall) or the above-described FR
A P sheet, a steel plate or the like is wound (for example, when the skeleton 12 is a pillar).

The FRP sheet is composed of a large number of FRP fibers which are aligned in one direction on a plane and adhered to each other. The FRP sheet is attached to the wall by, for example, a nut screwed into each of a plurality of anchor bolts (not shown) implanted in the skeleton 12 in advance, and is preferably orthogonal to the direction in which the FRP fiber extends. This is performed by pressing at least one of the left and right ends or the upper and lower ends of the FRP against the wall. In the FRP sheet wound around the pillar,
For example, both overlapping end portions are bonded with an adhesive, for example, and in the case of a steel plate wound around the column, the butt end portions are welded, for example.

Referring now to FIG. 6, as another example of a reinforcement, there is shown a so-called extra concrete layer 28 which has been struck to increase the thickness dimension of the frame 12. This concrete layer 28 is also assembled with a formwork (not shown) at a distance from the surface of the skeleton 12, and the formwork and the skeleton 1 are assembled.
2 and can be formed by casting concrete between them. In the illustrated example, prior to installing the formwork, a plurality of anchor members 30 projecting horizontally from the skeleton are implanted in the skeleton 12, and a plurality of horizontal streaks 32 placed on each anchor member 30 are provided. In addition, a vertical streak 34 extending perpendicular to each anchor member 30 is arranged. These anchor members 30, the horizontal stripes 32 and the vertical stripes 34 are embedded in the concrete layer 28.

Since the swelling agent 20 in each hole 18 has been completely removed, the expansion of the remaining swelling agent caused by absorbing the water in the new mortar layer 24 or the concrete layer 28 when the swelling agent is not removed is performed. Accordingly, no breakage or breakage of the new mortar layer 24 or the concrete layer 28 or separation of these layers 24 and 28 from the frame 12 occurs.

[Brief description of the drawings]

FIG. 1 is a front view of a part of a skeleton of a concrete building.

FIG. 2 is a schematic cross-sectional view taken along line 2-2 of FIG.

FIG. 3 is a cross-sectional view, similar to FIG. 2, of the skeleton after the swelling agent has been removed from the holes in the skeleton.

FIG. 4 is a schematic cross-sectional view of a skeleton in a state covered with a mortar layer formed after removing an expanding agent.

FIG. 5 is a cross-sectional view similar to FIG. 4 of a skeleton in a state in which a mortar layer formed after removing an expanding agent is used as a base layer and the periphery thereof is covered with an FRP sheet as a reinforcing material.

FIG. 6 is a view of the skeleton in a state of being covered with a reinforcing concrete layer which is a reinforcing material formed after removing the expanding agent.
It is sectional drawing similar to.

[Description of Signs] 10 Existing concrete building 12 Building 14 (Old) Mortar layer 16, 18 holes 20 Expanding agent 22 Large diameter hole 24 (New) Mortar layer 26 FRP sheet (Reinforcing material) 28 Additional concrete layer ( Reinforcement)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-125472 (JP, A) JP-A-9-165923 (JP, A) JP-A-58-54164 (JP, A) 118771 (JP, U) Actually open 63-59961 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) E04G 23/02-23/08 B02C 19/18

Claims (8)

(57) [Claims] 1. A method of exposing a skeleton of an existing concrete building covered with a mortar layer, the method comprising exposing a plurality of holes provided in the mortar layer to penetrate the mortar layer to crush the mortar layer. A method of exposing a skeleton, comprising: filling a swelling agent; removing crushed pieces of the mortar layer from the skeleton; and removing an swelling agent remaining in a hole reaching the inside of the skeleton among the plurality of holes. 2. The method according to claim 1, wherein said holes are formed by subjecting said mortar layer to ultrasonic cutting. 3. removing the expanding agent by spraying a large number of fine particles on the expanding agent remaining in the hole reaching the skeleton.
The method of claim 1. 4. The method according to claim 1, wherein the expanding agent remaining in the hole reaching the body is removed by scraping the expanding agent with a wire brush. 5. The method of claim 1, wherein the swelling agent is removed by drilling a portion of the skeleton defining a hole reaching the skeleton. 6. A method for reinforcing an existing concrete building having a skeleton covered with a mortar layer, wherein the plurality of holes provided in the mortar layer to penetrate the mortar layer to crush the mortar layer. After filling the swelling agent and removing the crushed pieces of the mortar layer from the skeleton, removing the swelling agent remaining in the holes reaching the inside of the skeleton among the plurality of holes, and thereafter covering the skeleton with a reinforcing material , How to reinforce existing concrete buildings. 7. A method for repairing an existing concrete building having a skeleton covered with a mortar layer, wherein the plurality of holes provided in the mortar layer and penetrating the mortar layer to crush the mortar layer. After filling the swelling agent and removing the crushed pieces of the mortar layer from the skeleton, removing the swelling agent remaining in the holes reaching the inside of the skeleton from among the plurality of holes, and thereafter, replacing the skeleton with a new mortar layer For repairing existing concrete buildings. 8. An expanding agent formed in the mortar layer for crushing a mortar layer covering a skeleton of an existing concrete building and remaining in a hole reaching the inside of the skeleton among a plurality of holes filled with an expanding agent. And removing a whole or a part of the crushed pieces of the mortar layer, and then spraying a large number of fine particles on an expanding agent remaining in a hole reaching the main body.