JP2019094664A - Method for removing cement-based member containing fibrous material - Google Patents

Abstract

To simply remove a cement-based member containing a fibrous material.SOLUTION: A method for removing a cement-based member containing a fibrous material includes: a chipped part forming step of forming a chipped part in the cement-based member containing the fibrous material, which is provided on a surface of a base material; a freezing expansion material filling step of filling the chipped part with a freezing expansion material; a freezing expansion step of freezing the freezing expansion material thereby expanding the same; and a removal step of removing the cement-based member containing the fibrous material, from the base material, after the freezing expansion step.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of removing a fibrous material-containing cement-based member.

  In existing buildings, etc., the asbestos fire-resistant coating (an example of a fibrous material-containing cement-based member) containing asbestos (asbestos) on the surface of the base is used as a fire-resistant coating on a metal base (for example, H-shaped steel) It has been applied. When the asbestos refractory coating is removed from the substrate, it is gradually removed using a tool such as a peeler (scraper) (see, for example, Patent Document 1).

JP, 2009-84049, A

  The asbestos refractory coating is a composite of asbestos fibers and cement, and the asbestos fibers are tightly intertwined with the cement. Therefore, it is difficult to remove the asbestos-resistant coating (the fibrous material-containing cement-based member) from the base material, which requires time and labor. In addition, in order to reduce the burden on the worker, for example, when an electric chipper is used, there is a problem that sound or vibration is generated.

  This invention is made in view of this subject, Comprising: The place made into the objective is to make it easy to peel off a fibrous material containing cement-based member, and to remove it simply.

In order to achieve such an object, the method for removing a fibrous material-containing cement-based member of the present invention comprises: forming a scraping portion in a fibrous material-containing cement-based member provided on the surface of a substrate; A freeze expansion material filling process of filling a freeze expansion material into a scraped part, a freeze expansion process of freezing and expanding the freeze expansion material, and the freeze expansion process after the freeze expansion process, the fibrous material-containing cement system member And removing the material.
According to the method for removing such a fibrous material-containing cement-based member, the fibrous material-containing cement-based member can be easily peeled off and can be easily removed.

In the method of removing a fibrous material-containing cement-based member, the removing step is preferably performed after the freeze-expanding material that has been frozen in the freeze-expanding step is melted.
According to such a method for removing a fibrous material-containing cement-based member, the fibrous material-containing cement-based member can be more easily removed.

In the method for removing a fibrous material-containing cement-based member, it is preferable that the scraping portion reaches an interface between the base and the fibrous-material-containing cement-based member.
According to such a method for removing a fibrous material-containing cement-based member, the fibrous material-containing cement-based member at the interface portion with the base material can be wetted with the freeze expansion material.

In the method of removing a fibrous material-containing cement-based member, it is desirable that the freeze-expanding material permeates the inside of the fibrous material-containing cement-based member.
According to such a method for removing a fibrous material-containing cement-based member, the fibrous material-containing cement-based member may be exfoliated at the interface between the fibrous material-containing cement-based member and the base material by the expansion deformation of the freeze expansion material. It can cause cracking.

In the method for removing a fibrous material-containing cement-based member, it is preferable that the freeze-expanding material permeates the interface between the base material and the fibrous-material-containing cement based member.
According to such a method for removing a fibrous substance-containing cement-based member, the fibrous substance-containing cement-based member can be easily peeled off at the interface with the base material.

  According to the present invention, it is possible to easily remove the fibrous material-containing cement-based member.

It is sectional drawing which shows the structure of the steel frame beam 10 which gave the fireproof coating 30 on the surface. It is a flowchart of the fireproof coating removal method of this embodiment. It is sectional drawing which shows the state in each process. It is sectional drawing which shows the state in each process. It is sectional drawing which shows the state in each process. It is sectional drawing which shows the state in each process. It is sectional drawing which shows the state in each process. FIG. 4A is a perspective view of the tool 100, and FIG. 4B is a conceptual view showing a use state of the tool 100. As shown in FIG. FIG. 5A is an explanatory view of a cut of a large-sized test body, and FIG. 5B is an explanatory view of a cut of a small-sized test body.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiment, the case of removing the asbestos fireproof coating (fibrous material-containing cement-based member) applied to the surface of the steel frame beam (base material) will be described.

=== Embodiments ===
<< About the composition of steel frame beams >>
FIG. 1: is sectional drawing which shows an example of a structure of the steel frame beam 10 which gave the fireproof coating 30 to the surface.

  As shown in FIG. 1, the steel frame beam 10 (corresponding to a base material) of the present embodiment is an H-shaped steel provided below the slab 20, and has plate-like upper flanges spaced apart from each other and facing each other. It has a plate-like web 16 connecting the upper and lower flanges 12 and 14 and the upper and lower flanges 12 and 14 at the center in the width direction. The fireproof coating 30 is provided by spraying etc. on each surface except the connection surface (upper surface of the upper flange 12) with the slab 20 among this steel frame beam 10. As shown in FIG. The fireproof coating 30 of the present embodiment is an asbestos fireproof coating containing asbestos (asbestos), and is a composite of asbestos fibers and cement. That is, the fireproof coating 30 corresponds to the fibrous material-containing cement-based member.

  When removing such a fireproof coating 30 from the steel girder 10, a worker generally inserts a sharp removal tool such as a peeler (scraper) into the surface of the fireproof coating 30 and moves the removal tool therefrom. The fireproof coating 30 is gradually peeled off and removed. However, since the fireproof coating 30 is composed of cement and asbestos closely intertwined with each other, it is difficult to remove by the method as described above, and it takes time and labor, and the working efficiency is poor. Moreover, when tools, such as an electric chipper, are used, there existed a problem which a sound and a vibration generate | occur | produce at the time of work.

  So, in this embodiment, it is made easy to peel off the fireproof coating 30, and it is made to be able to remove it simply.

<< About the fireproof coating removal method >>
FIG. 2: is a flowchart of the fireproof coating removal method of this embodiment, and FIG. 3A-FIG. 3E are sectional drawings which show the state in each process.

  In the present embodiment, as described later, the fireproof coating 30 is cut to form a cut (groove 32). Therefore, first, the location where a cut is to be made in the fireproof coating 30 is identified (FIG. 2: S10). It is desirable that the cut is made at a place where the refractory coating 30 can be removed by a block. In addition, it is desirable that the intervals of the incisions be determined by performing evaluations as in the examples described later. The broken line in FIG. 3A virtually shows an example of a cut portion (boundary portion of a block) in the present embodiment. It is good to show a place with a marker etc. in the part which makes a cut.

  Next, the fireproof coating 30 is cut in the depth direction using a cutting tool (for example, a circular cutter or a scratching tool) (FIG. 2: S11). Thus, as shown in FIG. 3B, the groove 32 (corresponding to a scraped portion) is formed in the fireproof coating 30. In the present embodiment, the groove 32 is formed to reach the surface of the steel frame beam 10 (in other words, the interface between the fireproof coating 30 and the steel frame beam 10). The cutting tool used for this cutting may be selected according to the hardness of the fireproof coating 30. For example, if the hardness is lower than a predetermined value (if it is soft), the fireproof coating 30 is pushed off using a circular cutter (round saw), and if the hardness is higher than a predetermined value (if it is hard), the fireproof coating is used using a scratching tool. You may scratch (tear) 30 and so on. As described above, the groove 32 can be easily formed by appropriately selecting the cutting tool used when forming the cutting portion on the fireproof coating 30 according to the hardness of the fireproof coating 30, thereby improving the work efficiency. be able to.

  After forming the grooves 32, as shown in FIG. 3C, the grooves 32 are filled with water (FIG. 2: S12). Water is a liquid at normal temperature and has a characteristic that its volume expands when it is frozen (when it changes from liquid to solid). That is, water corresponds to a freeze expansion material, and step S12 of filling the groove 32 with water corresponds to a freeze expansion material filling process. In the present embodiment, when the groove 32 is filled with water, the tool 100 shown in FIGS. 4A and 4B is used. FIG. 4A is a perspective view of the tool 100, and FIG. 4B is a conceptual view showing a use state of the tool 100. As shown in FIG. Here, as shown in the figure, the front and back direction is defined.

  The tool 100 is a scraper-shaped tool, and has a blade portion 110 and a grip portion 120.

  The tip end side (front side) of the blade portion 110 is formed in a thin plate shape. Moreover, the injection port 111 is provided in the end surface of the front side of the blade part 110 slender along the longitudinal direction.

  The gripping portion 120 is a portion gripped by the operator and is provided on the rear side of the blade portion 110. A supply port 121 is provided on the rear end surface of the grip portion 120.

  Further, in the inside of the tool 100, a flow path (not shown) for communicating the injection port 111 and the supply port 121 is provided.

  When filling the groove 32 with water, as shown in FIG. 4B, the tip portion of the blade portion 110 of the tool 100 is inserted along the groove 32. Then, water is supplied to the supply port 121 of the tool 100 by a pump (not shown) or the like. Thus, water is injected from the injection port 111 of the blade portion 110 and injected into the groove 32. By using such a scraper-shaped tool 100, the wide range of the groove 32 can be filled with water, and the working efficiency can be enhanced.

  The tool 100 can also be used as a cutting tool for forming the grooves 32 when the hardness of the fireproof coating 30 is low (if it is soft).

  In the present embodiment, when the groove 32 is filled with water, the tip end of the blade portion 110 of the tool 100 is inserted into the groove 32, but may not be inserted. For example, water may be injected or sprayed from the vicinity of the opening of the groove 32 to fill the groove 32 with water. Also in this case, since the groove 32 is formed, the groove 32 can be wetted to the interface with the steel frame beam 10. Further, the tool for filling the groove 32 with water is not limited to the tool 100. For example, in the same shape as the tool 100, a plurality of circular injection ports may be arranged at the tip. Also, for example, the groove 32 may be filled with water using a syringe-shaped tool.

  The water filled in the groove 32 penetrates into the interior of the fireproof coating 30. In particular, in the present embodiment, since the grooves 32 reach the interface between the fireproof coating 30 and the steel frame beam 10, water reliably penetrates the inside of the fireproof coating 30 at this interface portion. Thereby, the fireproof coating 30 around the groove 32 (in particular, the interface with the steel frame beam 10) is wetted. Although water is used to wet the fireproof coating 30 in the present embodiment, the present invention is not limited to water, and it may be a liquid that expands when frozen. For example, an aqueous solution such as an aqueous glycolic acid solution described later may be used.

  When the water sufficiently penetrates the fireproof coating 30, as shown in FIG. 3D, the coolant is sprayed or allowed to flow to freeze the water (FIG. 2: S13). In the present embodiment, liquid nitrogen is used as the refrigerant. Then leave it for several hours. When the water contained in the fireproof coating 30 is frozen by liquid nitrogen, the volume of water (in other words, the volume of the fireproof coating 30) expands, so interphase peeling (interfacial peeling) occurs at the interface between the fireproof coating 30 and the steel frame beam 10.

  Thereby, as shown to FIG. 3E, the fireproof coating 30 can be removed as a block (block) from the steel frame beam 10 (FIG. 2: S14). If the fireproof coating 30 does not peel off naturally, the fireproof coating 30 may be removed by inserting a removal tool (such as a peeler) into the groove 32. In the present embodiment, since the water contained in the fireproof coating 30 is expanded in the above-described step S13 and the peeling is easily generated at the interface with the steel frame beam 10, the removal tool is inserted into the cutting portion and the amount is small. The fireproof coating 30 can be peeled off from the steel frame beam 10 only by applying a force. Thus, in the present embodiment, the fireproof coating 30 can be easily removed. In addition, it is desirable to carry out the work of removing the fireproof coating 30 using a removal tool after waiting for the frozen water (fireproof coating 30) to melt. Thereby, the fireproof coating 30 can be removed more easily.

  As described above, in the fireproof coating removing method according to the present embodiment, the groove 32 is formed in the fireproof coating 30 provided on the surface of the steel frame beam 10 (cutting portion forming process), and Step S12 of filling (freeze-expanding material filling step), step S13 of freezing and expanding water (freeze-expansion step), and step S14 of removing the fireproof coating 30 from the steel frame beam 10 (removing step) There is. Thereby, the fireproof coating 30 can be easily exfoliated as a lump, and the improvement of working efficiency can be aimed at. Also, noise and vibration can be minimized.

<Example>
As an Example of this invention, the evaluation experiment about the removability of asbestos by water and liquid nitrogen was done.

(Formwork)
Two types of molds with different sizes and shapes are used. Formwork A: 300 mm × 300 mm rectangular formwork Formwork B: 140 mm diameter circular formwork

(Test body)
Each of the above-described molds was placed on a steel plate, and simulated asbestos having the following composition was poured into the molds so as to have a thickness of 50 mm to prepare a test body. The following base treatment materials were used for base treatment.
[Blending of simulated asbestos]
Pacific material Funen seal (wet material) (20 kg / bag) + cement 5% added, 17 to 25 kg of fresh water is added to 20 kg of funen seal, and it is stirred well.
[Base treatment material]
Acrylic emulsion solution (applied to mold with brush, curing from milky white to clear)

  In the following description, a test body (see FIG. 5A) manufactured using the mold frame A is referred to as a large-sized test body, and a test body manufactured using the mold frame B (see FIG. 5B) is referred to as a small test body.

  The test body was allowed to develop strength for 28 days in a constant temperature and humidity chamber (20 ° C., 65%), and then dried further until constant weight was achieved if constant weight was not reached.

  And the notch | incision (groove) was provided in each produced test body. FIG. 5A is an explanatory view of a cut of a large-sized test body. As shown in the figure, cuts were made with a saw or a rotary cutter so as to be 30 mm square and 50 mm square squares. This incision was formed to reach the steel plate surface (the interface between the simulated asbestos and the steel plate). Moreover, FIG. 5B is explanatory drawing of the notch | incision of a small test body. In the case of the small-sized test piece, as shown in FIG. 5B, a cut reaching the steel plate surface was made.

  Moreover, the test body (a large sized test body, a small sized test body) which does not provide a notch | incision was also produced as a comparative example.

(Test method)
-A frame was attached around the test body (simulated asbestos), and the following chemical solution 1 (water) or chemical solution 2 (glycolic acid aqueous solution) was poured from above the test body. In addition, 450 to 500 g was poured into the large-sized test body, and 150 g was poured into the small-sized test body.
Chemical solution 1 · · Water + surfactant (Capstone FS-30) 0.1 wt%
Chemical solution 2 · · Water + surfactant (Capstone FS-30) 0.1 wt% + glycolic acid 15 wt%
After the chemical solution penetrates the test body sufficiently, the liquid nitrogen is further poured and left for about 1 hour.

(Test results)
[In case of no cut (comparative example)]
-Although the chemical | medical solution penetrated to the depth of about 20-30 mm from the surface of simulated asbestos, it did not penetrate to a steel plate interface (50 mm).

  -In the large sized test body and small sized test body which the chemical | medical solution 2 was made to permeate, the crack (crack) had arisen in the position of the penetration depth (about 20 mm from the surface) of the chemical | medical solution. It is considered that this crack is caused by the volume expansion of the permeation portion of the chemical solution due to freezing of the chemical solution and the generation of stress between the portion to which the chemical solution does not permeate. On the other hand, in the large-sized test body to which the chemical solution 1 was infiltrated, no crack was generated at the penetration depth. In the small-sized test body to which the chemical solution 1 was infiltrated, a crack was generated at the penetration depth. It is considered that the lack of cracks in the large-sized test body to which the chemical solution 1 was infiltrated is due to insufficient cooling.

  In all cases, there was no change in the interface with the steel plate (peeling at the interface was not possible).

[When there is a cut]
The small test body to which the chemical solution 1 was infiltrated was exfoliated at the interface between the steel plate and the simulated asbestos, and could be easily removed. The small-sized test body to which the chemical solution 2 was infiltrated was inferior to the case of the chemical solution 1 in peelability.

  The large-sized test body to which the chemical solution 1 was infiltrated was exfoliated at the interface with the steel plate in the area where the small square grid (30 × 30 mm) was inserted, and could be easily removed. In the area | region which put the big square (50x50 mm), it was a mode that peeling did not advance a little.

  From this result, it was confirmed that the penetration of the chemical solution can be accelerated by making a cut in simulated asbestos, and it becomes easy to peel off at the interface with the steel plate. In particular, in the case of the chemical solution 1 (water), the permeation was remarkable and the peeling was easy.

  The reason why the drug solution 2 (glycolic acid aqueous solution) penetrates more slowly than the drug solution 1 (water) is considered to be that the drug solution 2 reacts with the cement component of the simulated asbestos and is accompanied by foaming. For this reason, it is thought that the releasability in the test object cut to the square is not better than in the case of the chemical solution 1.

=== Other Embodiments ===
The above embodiments are for the purpose of facilitating the understanding of the present invention, and are not for the purpose of limiting the present invention. It goes without saying that the present invention can be modified and improved without departing from the gist thereof, and that the present invention includes the equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<About steel frame beam 10>
In the above-mentioned embodiment, although the object (base material) in which fireproof coating 30 is provided was made steel frame beam 10, it does not restrict to this. For example, a pillar, a ceiling or a wall may be used. Moreover, although the steel frame beam 10 of the above-mentioned embodiment was H-shaped steel, it may be I-shaped steel or T-shaped steel. Moreover, a base material is not restricted to steel materials, For example, the member using metal materials, such as stainless steel and aluminum alloy, may be used.

<About fireproof coating 30>
In the foregoing embodiment, the fireproof coating 30 is formed by spraying, but may be a fireproof coating applied by a method other than spraying.

  Moreover, in the above-mentioned embodiment, although the fireproof coating 30 contained asbestos (asbestos), you may contain fibrous substances other than asbestos. For example, rock wool, glass fibers, metal fibers and the like may be contained.

  In addition, the removal method of the present embodiment may be applied to members for applications other than fireproof coating (for example, members provided for sound insulation).

<About the groove 32>
In the above-mentioned embodiment, although the linear groove 32 was formed in the fireproof coating 30, it does not restrict to this. For example, a plurality of circular drillings (corresponding to a cutting portion) may be formed in the fireproof coating 30 using a drill or the like. Also in this case, it is desirable to form holes up to the interface between the fireproof coating 30 and the steel frame beam 10. Then, a nozzle or the like may be inserted into each hole to be filled with water (water may be infiltrated into the refractory coating 30), and the water may be frozen and expanded with liquid nitrogen. By doing this, the fireproof coating 30 and the steel frame beam 10 can be peeled off at the interface, and the fireproof coating 30 can be easily removed.

  Moreover, although the groove 32 reaches the surface of the steel frame beam 10 (the interface of the fireproof coating 30 and the steel frame beam 10) in the above-mentioned embodiment, it is not restricted to this, the groove 32 is the steel frame beam 10 and the fireproof coating 30 It does not have to reach the interface. Also in this case, the thickness of the fireproof coating 30 at the portion where the groove 32 is provided is reduced, so that water can more easily penetrate to the interface with the steel frame beam 10 as compared with the portion where the groove 32 is not provided. Moreover, even if water does not penetrate to the interface with the steel frame beam 10, by freezing and expanding the water, a crack can be generated at a position near the interface, and the removability of the fireproof coating 30 is enhanced. Can.

10 steel frame beams (base material)
12 upper flange 14 lower flange 16 web 30 fireproof coating (fiber material-containing cement-based member)
32 groove (cutting part)
DESCRIPTION OF SYMBOLS 100 tool 110 blade part 111 injection port 120 holding part 121 supply port

Claims (5)

A cutting portion forming step of forming a cutting portion on a fibrous material-containing cement-based member provided on the surface of a base material,
A freeze expansion material filling step of filling the cut portion with a freeze expansion material;
Freeze expansion step of freezing and expanding the freeze expansion material;
A removal step of removing the fibrous material-containing cement-based member from the base material after the freezing and expanding step;
A method of removing a fibrous material-containing cement-based member, comprising: A method of removing a fibrous material-containing cement-based member according to claim 1, wherein
The method for removing a fibrous material-containing cement-based member according to claim 1, wherein the removing step is performed after the freeze-expanding material frozen in the freezing and expanding step is melted. A method of removing a fibrous material-containing cement-based member according to claim 1 or 2,
The method for removing a fibrous material-containing cement-based member, wherein the scraping portion reaches an interface between the base material and the fibrous material-containing cement-based member. A method for removing a fibrous material-containing cement-based member according to any one of claims 1 to 3, wherein
The method for removing a fibrous material-containing cement-based member, wherein the freeze expansion material penetrates into the inside of the fibrous material-containing cement-based member. A method of removing a fibrous material-containing cement-based member according to any one of claims 1 to 4, wherein
The method for removing a fibrous material-containing cement-based member, wherein the freeze expansion material penetrates the interface between the base material and the fibrous material-containing cement-based member.