Method for removing hardened cement body

Abstract

To provide a method of removing a cement hardened body capable of increasing the reusability of construction materials.SOLUTION: The removal method of a cement hardened body 30 is a method for removing the cement hardened body 30 adhering to a construction material 20 from the construction material 20. The method includes: a drying step of bringing the cement hardened body 30 to an absolutely dry state or a state approximating it by drying the construction material 20 at a drying temperature below the firing temperature of the glaze contained in a surface film 22 of the construction material 20; and a dipping step of dipping the construction material 20 in an acid solution after the drying step.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for removing a cement hardened body.

Background Art

[0002] Conventionally, as one of the techniques for reusing construction members removed from the outer wall, after drying a construction member with a cement hardened body attached thereto at a drying temperature equal to or lower than the firing temperature of the construction member, the construction member is immersed in an acid solution to remove the cement hardened body. A technique has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional technique, as described above, since a construction member with a cement hardened body attached thereto is dried at a drying temperature equal to or lower than the firing temperature of the construction member, for example, when this drying temperature is higher than the firing temperature of the glaze contained in the surface film of the construction member, there is a risk that the surface film will change color due to the heat during drying. Therefore, there was room for improvement from the viewpoint of the reusability of the construction member.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a method for removing a cement hardened body that can enhance the reusability of a construction member.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, the method for removing a cement hardened body according to claim 1 is a method for removing a cement hardened body adhering to a construction member from the construction member, comprising drying the construction member at a drying temperature lower than the firing temperature of the glaze contained in the surface film of the construction member to bring the cement hardened body into an absolutely dry state or an approximate state thereof, and after the drying step, immersing the construction member in an acid solution. including, in the drying step, drying the construction member at a drying temperature of from 100°C to less than 500°C.

[0007] The method for removing a cement hardened body according to claim 2 is the method for removing a cement hardened body according to claim 1, wherein In the drying step, the construction member is dried at a drying temperature of about 100°C for at least 3 hours or more.

[0008] The method for removing a cement hardened body according to claim 3 is Claim 1 or 2 in the method for removing a cement hardened body according to claim 1, wherein In the dipping step, the construction member is dipped in the acid solution at about 50°C to 90°C.

[0009] The method for removing a cement hardened body according to claim 4 is A removal method for removing a cement hardened body adhering to a construction member from the construction member, comprising: a drying step of drying the construction member at a drying temperature lower than the firing temperature of the glaze contained in the surface film of the construction member, thereby bringing the cement hardened body into an absolutely dry state or an approximate state thereof; a dipping step of dipping the construction member in an acid solution after the drying step; and a pre-dipping step of dipping the construction member in an acid solution at room temperature after the drying step and before the dipping step.

Advantages of the Invention

[0011] According to the method for removing a cement hardened body according to claim 1, by drying the construction member at a drying temperature lower than the firing temperature of the glaze contained in the surface film of the construction member, a drying step of bringing the cement hardened body into an absolutely dry state or an approximate state thereof, and after the drying step, an immersion step of immersing the construction member in an acid solution are included. Therefore, compared with the prior art (a technique of drying a construction member at a drying temperature not higher than the firing temperature of the construction member and then immersing it in an acid solution), while effectively removing the cement hardened body from the construction member, discoloration of the surface film of the construction member can be suppressed, and the reusability of the construction member can be enhanced. Further, in the drying step, since the construction member is dried at a drying temperature of from 100°C to less than 500°C, it is possible to surely avoid discoloration of the surface film of the construction member, and the reusability of the construction member can be further enhanced.

[0012] According to the method for removing a cement hardened body according to claim 2, In the drying step, since the construction member is dried at a drying temperature of about 100°C for at least 3 hours or more, it is possible to surely avoid discoloration of the surface film of the construction member while surely bringing the state of the cement hardened body into an absolutely dry state or an approximate state thereof.

[0013] According to the method for removing a cement hardened body according to claim 3, In the dipping step, since the construction member is dipped in an acid solution at about 50°C to 90°C, it is possible to shorten the dipping step while effectively removing the cement hardened body.

[0014] According to the method for removing a cement hardened body described in claim 4, Comprising a drying step of drying the construction member at a drying temperature lower than the firing temperature of the glaze contained in the surface film of the construction member, thereby bringing the cement hardened body into an absolutely dry state or an approximate state thereof, and a dipping step of dipping the construction member in an acid solution after the drying step. Therefore, compared with the prior art (a technique of drying a construction member at a drying temperature equal to or lower than the firing temperature of the construction member and then dipping it in an acid solution), it is possible to effectively remove the cement hardened body from the construction member while suppressing discoloration of the surface film of the construction member, and to enhance the reusability of the construction member. Further, since it further includes a pre-dipping step of dipping the construction member in an acid solution at room temperature after the drying step and before the dipping step, it is possible to promote the removal of the cement hardened body in the dipping step, and further shorten the dipping step.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0017] With reference to the accompanying drawings, embodiments of a method for removing a cement hardened body according to the present invention will be described in detail. First, [I] the basic concept of the embodiment will be described, then [II] the specific content of the embodiment will be described, and finally, [III] modifications to the embodiment will be described. However, the present invention is not limited by the embodiments.

[0018] [I] Basic Concept of the Embodiment First, the basic concept of the embodiment will be described. The embodiment generally relates to a removal method for removing a cement hardened body adhering to a construction member from the construction member.

[0019] Here, the specific structure and type of the "construction member" are arbitrary. For example, it includes exterior materials (such as tile-based exterior materials, brick-based exterior materials, stone-based exterior materials) and interior materials (such as tile-based interior materials, brick-based interior materials, stone-based exterior materials) attached to the framework of a structure (as an example, columns, walls, floors, or ceilings). In the embodiment, it will be described as a tile-based exterior material for walls.

[0020] Also, the specific structure and type of the "structure" are arbitrary. For example, it includes building structures such as office buildings, commercial facilities, public facilities, and apartment buildings like condominiums, as well as civil engineering structures such as tunnels and dams. In the embodiment, it will be described as an office building.

[0021] Also, the "cement hardened body" is used for attaching a construction member to the framework body described later. For example, it includes a base material or / and an adhesive material containing at least cement as a component. In the embodiment, it will be described as including a base material and an adhesive material made of mortar.

[0022] In addition, the specific use of the construction member from which the cement hardened body has been removed by this removal method is arbitrary. For example, it may be reused as an exterior material or an interior material on the frame of the structure to which the construction member was attached or on the frame of a different structure, or it may be used for other purposes other than exterior or interior materials (as an example, a fence material for a flower bed, etc.).

[0023] [II] Specific Contents of the Embodiment Next, the specific contents of the embodiment will be described.

[0024] (Configuration) First, the configuration of the frame of a structure (specifically, an office building) including a construction member to which the method for removing a cement hardened body according to the embodiment is applied will be described.

[0025] FIG. 1 is a diagram conceptually showing the frame according to the embodiment of the present invention, where (a) is a front view and (b) is a cross-sectional view taken along the line A-A.

[0026] In the following description, the X direction in FIG. 1 is the left-right direction of the frame (-X direction is the left direction of the frame, +X direction is the right direction of the frame), the Y direction in FIG. 1 is the front-back direction of the frame (+Y direction is the front direction of the frame, -Y direction is the back direction of the frame), and the Z direction in FIG. 1 is the up-down direction of the frame (+Z direction is the up direction of the frame, -Z direction is the down direction of the frame).

[0027] The frame 1 is a wall (for example, an outer wall, etc.) constituting the structure, and as shown in FIG. 1, it includes a frame body 10, a construction member 20, and a cement hardened body 30.

[0028] (Configuration - Frame Body) The frame body 10 is the basic structure of the frame 1. This frame body 10 is formed of, for example, a long rectangular plate-like body made of concrete (as an example, made of reinforced concrete or prestressed concrete), and as shown in FIG. 1, it is provided such that the longitudinal direction is along the up-down direction and is fixed to an installation target (for example, a floor part, etc.) not shown.

[0029] (Configuration - Construction Member) The building member 20 is composed of, for example, a known tile-based exterior material or the like. As shown in FIG. 1, it is provided to cover the entire outer surface of the building body 10 (the entire front surface in FIG. 1) outside the building body 10, and includes a building member main body 21 and a surface film 22.

[0030] (Configuration - Building Member - Building Member Main Body) The building member main body 21 is the basic structure of the building member 20. This building member main body 21 is composed of, for example, a known tile material (as an example, a rectangular tile material having a tile portion and a joint portion), etc. As shown in FIG. 1, a plurality of them are arranged in parallel substantially along the left - right direction and a plurality of them are arranged in parallel substantially along the up - down direction so as to cover the building body 10.

[0031] Also, regarding the specific configuration of the building member main body 21, in the embodiment, it is configured as follows.

[0032] That is, as shown in FIG. 1, the entire outer surface of the building member main body 21 (the entire front surface in FIG. 1) is formed in a flat shape. However, it is not limited to this, and for example, it may be formed in a non - flat shape. Also, the entire inner surface of the building member main body 21 (the entire rear surface in FIG. 1) is formed in a non - flat shape, specifically, it is formed to have a plurality of convex portions protruding rearward.

[0033] (Configuration - Building Member - Surface Film) The surface film 22 is a film coated with glaze. This surface film 22 is provided on the entire outer surface of the building member main body 21 as shown in FIG. 1(b). Specifically, for example, glaze for exterior tile materials is applied to the entire outer surface of the building member main body 21 and baked to form it.

[0034] Here, the "glaze" refers to a chemical used to enhance the decorativeness and strength of the construction member 20 and to prevent the construction member 20 from getting dirty. Specifically, it is a chemical composed of the RO2 component (e.g., SiO2 component, etc.) that forms the framework of the glaze, the R2O3 component (e.g., Al2O3 component, etc.) that connects with the construction member body 21 and forms part of the framework of the glaze, the RO component (CaO component, MgO component) that partially breaks down the framework of the glaze and lowers the melting temperature, and the R2O component (Na2O component, K2O component, etc.).

[0035] Also, the specific type of the "glaze" is arbitrary. For example, "transparent glaze" which is amorphous, "matte glaze / devitrified glaze" which contains fine crystals not incorporated into the amorphous phase, "crystal glaze" which contains large crystals, "opal glaze" which has multiple amorphous phases, etc. are applicable.

[0036] Also, the above-mentioned various glazes are roughly classified into low-fire glazes and high-fire glazes. Among them, the "low-fire glaze" is a glaze with a relatively low firing temperature (e.g., about 750°C to 1100°C for the firing temperature), and for example, alkali glaze, raster glaze, etc. are applicable. Also, the "high-fire glaze" is a glaze with a firing temperature higher than that of the low-fire glaze (e.g., about 1100°C to 1300°C for the firing temperature), and for example, lime glaze, ash glaze, etc. are applicable.

[0037] Also, the coating amount of the glaze is arbitrary. From the perspective of forming a uniform surface film 22, it is desirable to set it as small as possible. However, since it may vary depending on the type of the glaze, the type of the construction member body 21, etc., for example, it may be set based on experimental results, analysis results, etc.

[0038] (Configuration - Cement Hardened Body) The cement hardened body 30 is for attaching the construction member 20 to the housing body 10. As shown in Fig. 1(b), this cement hardened body 30 is provided between the housing body 10 and the construction member body 21.

[0039] Also, although the specific configuration of the cement hardened body 30 is arbitrary, in the embodiment, as shown in FIG. 1(b), it includes a base portion 31 and an adhering portion 32.

[0040] Among these, the base portion 31 is for leveling the unevenness of the building body 10. This base portion 31 is configured using, for example, a known base material made of mortar, and as shown in FIG. 1(b), it is provided so as to substantially cover the entire outer surface of the building body 10.

[0041] Also, the adhering portion 32 is for attaching the construction member 20 to the base material. This adhering portion 32 is configured using, for example, a known adhering material made of mortar, and as shown in FIG. 1(b), it is provided so as to substantially cover the entire outer surface of the base portion 31.

[0042] (Method for Removing Cement Hardened Body) Next, the method for removing the cement hardened body 30 according to the embodiment will be described.

[0043] FIG. 2 is a diagram showing the preparation step of the method for removing the cement hardened body 30. FIG. 3 is a diagram showing the drying step of the method for removing the cement hardened body 30. FIG. 4 is a diagram showing the pre - immersion step of the method for removing the cement hardened body 30. FIG. 5 is a diagram showing the immersion step of the method for removing the cement hardened body 30, where (a) is a diagram showing the state where the construction member 20 is immersed in the acid solution, and (b) is a diagram showing the state where the construction member 20 is being scrubbed.

[0044] The method for removing the cement hardened body 30 according to the embodiment is a method for removing the cement hardened body 30 adhering to the construction member 20 from the construction member 20, and as shown in FIGS. 2 to 5, it includes a preparation step, a drying step, a pre - immersion step, and an immersion step.

[0045] (Method for Removing Cement Hardened Body - Preparation Step) Returning to FIG. 2, first, the preparation step will be described.

[0046] The preparation process is a process for preparing to remove the cement hardened body 30 from the construction member 20.

[0047] Specifically, first, as shown in FIG. 2, a part of the construction member 20 is cut together with the cement hardened body 30 using a known cutting tool (not shown), and then the cut construction member 20 and the cement hardened body 30 are peeled from the housing body 10 using a known peeling tool (not shown). In this case, for example, in order to enhance the reusability of the construction member 20, it is desirable to cut the construction member 20 such that at least one or more tile portions of the construction member body 21 are included in the cutting region, and to cut the joint portion of the construction member body 21 without cutting the tile portion of the construction member body 21.

[0048] (Method for Removing Cement Hardened Body - Drying Process) Next, the drying process will be described.

[0049] The drying process is a process of drying the construction member 20 at a drying temperature below the firing temperature of the glaze contained in the surface film 22 of the construction member 20 after the preparation process, so as to bring the cement hardened body 30 into an absolutely dry state or an approximate state thereof.

[0050] Here, the reason for drying the construction member 20 until it reaches an absolutely dry state or an approximate state thereof is to remove the moisture inside the cement hardened body 30 adhering to the construction member 20 by this drying, so as to facilitate the penetration of the first acid solution AL1 described later or the second acid solution AL2 described later into the inside of the cement hardened body 30. Note that the "absolutely dry state or an approximate state thereof" corresponds to, for example, a state where the moisture content of the construction member 20 is about 5% or less.

[0051] Also, the reason for drying the construction member 20 at a drying temperature below the firing temperature of the glaze contained in the surface film 22 is that if the construction member 20 is dried at a drying temperature exceeding the firing temperature of the glaze contained in the surface film 22, the glaze may melt again due to the heat during this drying, and thus the surface film 22 may change color (for example, turn white, etc.). Therefore, this is to avoid such problems.

[0052] Also, regarding the details of the processing content of the drying process, as shown in FIG. 3, using a known drying device 41 (for example, a muffle furnace, etc.), the construction member 20 is dried at a drying temperature lower than the firing temperature of the glaze contained in the surface film 22 (specifically, a drying temperature lower than the firing temperature of the construction member 20) for a predetermined time.

[0053] Also, although the specific method of setting the above drying temperature is arbitrary, in the embodiment, in order to prevent discoloration of the surface film 22 even with various types of glazes and effectively dry the cement hardened body 30, it is set to about 100°C to 700°C based on the test results of the first removal confirmation test and the discoloration confirmation test described later.

[0054] However, when the above drying temperature is close to the firing temperature of the glaze (for example, when the above drying temperature = 700°C while the firing temperature of the glaze (specifically, low-fire glaze) = 750°C, etc.), there is a possibility that the surface film 22 of the construction member 20 may discolor. Therefore, in order to surely avoid the discoloration of the surface film 22, it is more preferable to set it to less than 500°C from 100°C based on the test results of the discoloration confirmation test described later.

[0055] Also, although the specific method of setting the above predetermined time is arbitrary, for example, based on the test results of the drying test described later, the construction member 20 may be dried at a drying temperature of about 100°C for at least 3 hours or more. Thereby, while surely avoiding the discoloration of the surface film 22 of the construction member 20, the state of the cement hardened body 30 can be surely made into an absolutely dry state or an approximate state thereof. However, it is not limited to this. For example, when the construction member 20 is at a drying temperature of 100°C or higher, it may be dried for 3 hours or more, or may be dried for less than 3 hours.

[0056] By such a drying process, it becomes possible to make the cement hardened body 30 into an absolutely dry state or an approximate state thereof while avoiding the discoloration of the surface film 22.

[0057] (Method for Removing Cement Hardened Body - Pre-Immersion Step) Next, the pre-immersion step will be described.

[0058] The pre-immersion step is a step of immersing the construction member 20 in a room-temperature acid solution AL1 (hereinafter referred to as the "first acid solution AL1") after the drying step and before the immersion step.

[0059] Here, the reason for performing the pre-immersion step is to shorten the penetration time of the second acid solution AL2, which will be described later, into the cement hardened body 30 by allowing the first acid solution AL1 to penetrate into the interior of the cement hardened body 30 adhering to the construction member 20.

[0060] Also, regarding the details of the processing content of the pre-immersion step, as shown in FIG. 4, the construction member 20 dried in the drying step is put into a first container 42 containing the room-temperature first acid solution AL1, and the construction member 20 is immersed in the first acid solution AL1 for about 20 hours (or a time less than 20 hours or exceeding 20 hours).

[0061] Also, the amount of the first acid solution AL1 contained in the first container 42 is arbitrary as long as the entire cement hardened body 30 can be immersed. However, in the embodiment, as shown in FIG. 4, it may be set to an amount such that both the construction member 20 and the cement hardened body 30 are completely immersed. However, it is not limited to this. For example, it may be set to an amount such that the cement hardened body 30 is completely immersed but a part of the construction member 20 is not immersed in the first acid solution AL1 (note that the amount of the second acid solution AL2 contained in the second container 52, which will be described later, is also substantially the same).

[0062] Regarding the type of acid contained in the first acid solution AL1, it is arbitrary as long as it can react with at least some components of the cement hardened body 30 to dissolve the cement hardened body 30. For example, hydrochloric acid, nitric acid, sulfuric acid, citric acid, hydroiodic acid, perchloric acid, hydrobromic acid, chloric acid, bromic acid, iodic acid, perbromic acid, metaperiodic acid, permanganic acid, thiocyanic acid, aqua regia, malic acid, lactic acid, glycolic acid, oxalic acid, malonic acid, succinic acid, phthalic acid, acetic acid, formic acid, tartaric acid, benzoic acid, propionic acid, butyric acid, valeric acid, etc. can be used (note that the same applies to the type of acid contained in the second acid solution AL2 described later).

[0063] Regarding the method of setting the acid concentration of the first acid solution AL1, it is arbitrary. In the embodiment, it is set to the same concentration as the acid concentration of the second acid solution AL2 described later. However, it is not limited to this. For example, it may be set to a concentration lower than the acid concentration of the second acid solution AL2 described later, or it may be set to a concentration higher than the acid concentration of the second acid solution AL2 described later.

[0064] By such a pre-immersion step, the removal of the cement hardened body 30 in the immersion step can be promoted, and the immersion step can be shortened.

[0065] (Method for removing cement hardened body - Immersion step) Next, the immersion step will be described.

[0066] The immersion step is a step of immersing the construction member 20 in an acid solution AL2 (hereinafter referred to as "second acid solution AL2") after the drying step and the pre-immersion step.

[0067] Specifically, in order to effectively remove the cement hardened body 30, after immersing the construction member 20 pre-immersed by the pre-immersion step in the second acid solution AL2 at a predetermined temperature for a predetermined period, the cement hardened body 30 is removed from the construction member 20 by a predetermined removal method, and this is repeated a plurality of times.

[0068] More specifically, as shown in Fig. 5(a), the construction member 20 is put into the second container 52 containing the second acid solution AL2 heated to about 50°C to 90°C by a known heating device 51 (for example, a gas heating device, etc.), and the construction member 20 is immersed in the second acid solution AL2 for about 15 minutes. Then, as shown in Fig. 5(b), using a known brush 53 or the like, the immersed construction member 20 is scrubbed in the third container 54 containing water W (for example, pure water), thereby removing the dissolved cement hardened body 30 from the construction member 20. Then, based on the test results of the fourth removal confirmation test described later, these series of operations are repeated 4 times (that is, while scrubbing the construction member 20, the construction member 20 is immersed in the second acid solution AL2 for a total of 60 minutes).

[0069] However, it is not limited to this. For example, the above series of operations may be performed 5 times or more. Alternatively, until the cement hardened body 30 is completely removed, after immersing the construction member 20 in the second acid solution AL2 for a period exceeding 15 minutes (or less than 15 minutes), scrubbing the construction member 20 may be repeated a plurality of times. Alternatively, scrubbing the construction member 20 may be omitted, and the construction member 20 may simply be immersed in the second acid solution AL2 for 60 minutes (or a period exceeding 60 minutes).

[0070] Here, the reason for setting the temperature of the second acid solution AL2 to about 50°C to 90°C is as follows. That is, as shown in the test results of the third removal confirmation test described later, when the temperature of the second acid solution AL2 is set to the boiling point or a temperature near it, the acid concentration (specifically, the titration concentration of the acid) of the second acid solution AL2 may decrease as the immersion period elapses, and there is a risk that the acid concentration of the second acid solution AL2 cannot be maintained. Also, when the temperature of the second acid solution AL2 is set to less than 50°C, since the removal effect of the cement hardened body 30 is lower than when the temperature of the second acid solution AL2 is 50°C or higher, there is a risk that it becomes difficult to shorten the immersion process. Therefore, it is to effectively remove the cement hardened body 30 while avoiding these problems.

[0071] Also, the method for setting the acid concentration of the second acid solution AL2 is arbitrary, but in the embodiment, it is set to about 3 wt% to 35 wt% based on the test results of the second removal confirmation test and the third removal confirmation test described later. More specifically, in order to effectively remove the cement hardened body 30, it is preferably set to about 35 wt%.

[0072] Regarding the above-described predetermined removal method, as described above, it has been described as rubbing and washing the construction member 20, but it is not limited thereto. For example, it may be to apply warm air to the construction member 20, immerse the construction member 20 in boiling water, or a combination thereof.

[0073] By such an immersion step, the cement hardened body 30 can be effectively removed.

[0074] By the removal method as described above, compared with the prior art (a technique of drying a construction member at a drying temperature lower than the firing temperature of the construction member and then immersing it in an acid solution), while effectively removing the cement hardened body 30 from the construction member 20, discoloration of the surface film 22 of the construction member 20 can be suppressed, and the reusability of the construction member 20 can be enhanced.

[0075] (Test Results) Next, various test results obtained by the applicant of the present application will be described. Here, the first removal confirmation test to the fourth removal confirmation test, the discoloration confirmation test, and the drying confirmation test will be described.

[0076] (Test Results - First Removal Confirmation Test - Overview) Next, the overview of the first removal confirmation test will be described.

[0077] The first removal confirmation test is a test for confirming the removal amount of the cement hardened body 30 in each test body under various test conditions (specifically, the condition of the presence or absence of a drying step).

[0078] The test method for this first removal confirmation test is optional, but it is as follows. That is, first, the mass of each test piece is measured using a known mass measuring instrument. Next, a drying process (specifically, using the drying device 41, drying the test piece A2 described later at about 100 °C for about 3 hours) is performed only on the test piece A2 described later. Also, each test piece is put into the corresponding second container 52 containing the second acid solution AL2 with an acid concentration of 35% by weight and at 80 °C, and the test piece is immersed for about 15 minutes. Then, after the above immersion, the mass of each test piece is measured again using the mass measuring instrument, and the mass reduction amount indicating the mass difference before and after immersion is calculated.

[0079] Also, the test pieces used in the first removal confirmation test are divided into test piece A1 and test piece A2. Here, test piece A1 and test piece A2 are test pieces made of a tile material with a planar shape of 45 mm × 45 mm for the construction member 20, a cement hardened body 30 attached to the construction member 20, an adhesive material made of mortar with a thickness of about 20 mm, and a base material made of mortar with a thickness of about 20 mm.

[0080] (Test Results - First Removal Confirmation Test - Details of Test Results) Next, the details of the test results of the first removal confirmation test will be described. Figure 6 is a diagram showing the test results of the first removal confirmation test.

[0081] As shown in Figure 6, for test piece A2, it was confirmed that the mass reduction amount was larger than that of test piece A1. In particular, regarding the mass reduction amount of test piece A2, it was confirmed that it was about 4 times the mass reduction amount of test piece A1, even though the immersion time of the second acid solution AL2 in test piece A2 was shorter than the immersion time of the second acid solution AL2 in test piece A1.

[0082] From the above, the effectiveness of performing the drying process was confirmed.

[0083] (Test Results - Discoloration Confirmation Test - Overview) Next, the overview of the discoloration confirmation test will be described.

[0084] The discoloration confirmation test is a test for confirming the presence or absence of discoloration of each test piece when dried at various drying temperatures.

[0085] The test method for this discoloration confirmation test is arbitrary, but it is as follows. That is, first, using the drying device 41 (the drying device 41 with a heating rate of 2.5 to 3.0 °C / min), each test piece is dried at a predetermined drying temperature for a predetermined time. Specifically, for test pieces B1 and B3, they are dried at about 450 °C for 180 minutes after reaching the target temperature, for test pieces B4 and B6, they are dried at about 700 °C for 180 minutes after reaching the target temperature, and for test pieces B7 and B9, they are dried at about 900 °C for 120 minutes after reaching the target temperature. Then, after drying each test piece, the test piece is naturally cooled inside the drying device 41.

[0086] Also, the test pieces used in the discoloration confirmation test are divided into test pieces B1 to B9. Here, test pieces B1 to B9 are floor tiles installed in a building. Also, the colors of test pieces B1, B4, and B7 are red, the colors of test pieces B2, B5, and B8 are blue, and the colors of test pieces B3, B6, and B9 are beige.

[0087] (Test Results - Discoloration Confirmation Test - Details of Test Results) Next, the details of the test results of the discoloration confirmation test will be described. Figure 7 is a diagram showing the test results of the discoloration confirmation test.

[0088] As shown in Figure 7, for test pieces B1 to B6, although no discoloration was confirmed on the surface film 22, for test pieces B7 and B9, discoloration (specifically, whitening of the surface film 22) was confirmed on the surface film 22.

[0089] From the above, the effectiveness of drying the construction member 20 at a drying temperature below the firing temperature of the glaze contained in the surface film 22 of the construction member 20 was confirmed.

[0090] (Test Results - Drying Confirmation Test - Overview) Next, the outline of the drying confirmation test will be described.

[0091] The drying confirmation test is a test for confirming the dry state of the test piece.

[0092] The test method for this drying confirmation test is arbitrary, but it is as follows. That is, first, the mass of the test piece is measured using a known mass measuring device. Next, the test piece is dried at about 100°C using the drying device 41. Then, during the above drying, every time a predetermined time elapses (specifically, every 0.5 hours, 1 hour, 2 hours, 3 hours, 24 hours), the mass of the test piece is measured using a known mass measuring device, and the moisture content for each of the above predetermined times is calculated.

[0093] Also, the test piece used in the drying confirmation test is a test piece configured substantially the same as the test piece A1.

[0094] (Test Results - Drying Confirmation Test - Details of Test Results) Next, the details of the test results of the drying confirmation test will be described. FIG. 8 is a diagram showing the test results of the drying confirmation test.

[0095] As shown in FIG. 8, when the drying time was less than 3 hours, although the moisture content of the test piece was 5% or more, when the drying time was 3 hours or more, it was confirmed that the moisture content of the test piece became less than 5%.

[0096] From the above, the effectiveness of drying the construction member 20 at a drying temperature of about 100°C for at least 3 hours or more was confirmed.

[0097] (Test Results - Second Removal Confirmation Test - Outline) Next, the outline of the second removal confirmation test will be described.

[0098] The second removal confirmation test is a test for confirming the removal amount of the cement hardened body 30 in each test piece under various test conditions (specifically, temperature conditions and acid concentration conditions of the second acid solution AL2).

[0099] The test method for this second removal confirmation test is optional, but it is as follows. That is, first, the mass of each test specimen is measured using a known mass measuring instrument. Next, each test specimen is put into the corresponding second container 52 containing the second acid solution AL2 (specifically, an acid solution containing hydrochloric acid), and the test specimen is immersed for a predetermined period. Then, during and after the immersion, the mass of each test specimen is measured using a mass measuring instrument.

[0100] Here, regarding the setting of the temperature of the second acid solution AL2, for the test specimens C1 and C2 described later, it is set to room temperature, and for the test specimen C3 described later, it is set to 80°C.

[0101] Also, regarding the setting of the acid concentration of the second acid solution AL2, for the test specimen C1 described later, it is set to about 3% by weight (1 mol / L), and for the test specimens C2 and C3 described later, it is set to about 35% by weight (11.38 mol / L).

[0102] Also, the test specimens used in the second removal confirmation test are divided into test specimens C1 to C3. Here, the test specimens C1 to C3 are test specimens configured substantially the same as the test specimen A1.

[0103] (Test Results - Second Removal Confirmation Test - Details of Test Results) Next, the details of the test results of the second removal confirmation test will be described. FIG. 9 is a diagram showing the test results of the second removal confirmation test.

[0104] As shown in FIG. 9, for the test specimens C1 to C3, it was confirmed that the mass decreased as the immersion period elapsed. Also, for the test specimens C2 and C3, it was confirmed that the mass decreased in a shorter immersion period than that of the test specimen C1. In particular, it was confirmed that the dissolution amount until the mass of the mortar in the test specimen C3 reached about 85% was about 72 times the dissolution amount until the mass of the mortar in the test specimen C1 reached about 85%.

[0105] From the above, the effectiveness of immersing the construction member 20 in the second acid solution AL2 with an acid concentration of about 3 wt% to 35 wt% and at about 80°C was confirmed.

[0106] (Test Results - Third Removal Confirmation Test - Overview) Next, the overview of the third removal confirmation test will be described.

[0107] The third removal confirmation test is a test for confirming the removal amount of the cement hardened body 30 in each test specimen under various test conditions (specifically, temperature conditions and acid concentration conditions of the second acid solution AL2).

[0108] The test method for this third removal confirmation test is arbitrary, but it is as follows. That is, first, the mass of each test specimen is measured using a known mass measuring instrument. Next, each test specimen is put into the corresponding second container 52 containing the second acid solution AL2, and the test specimen is immersed for 60 minutes. Then, after the above immersion, the mass of each test specimen is measured again using the mass measuring instrument, the mass reduction amount indicating the mass difference before and after immersion is calculated, and the titration concentration of the second acid solution AL2 in each second container 52 is measured using a known measuring method.

[0109] Here, regarding the setting of the temperature of the second acid solution AL2, for test specimens D1 to D3 described later, it is set to the boiling point temperature of the second acid solution AL2, for test specimens E1 to E3 described later, it is set to 80°C, for test specimens F1 to F3 described later, it is set to 50°C, and for test specimens G1 to G3 described later, it is set to 20°C.

[0110] Also, regarding the setting of the acid concentration of the second acid solution AL2, for test specimens D1, E1, F1, and G1 described later, it is set to 8.75 wt%, for test specimens D2, E2, F2, and G2 described later, it is set to 20 wt%, and for test specimens D3, E3, F3, and G3 described later, it is set to 35 wt%.

[0111] Also, the test specimens used in the third removal confirmation test are divided into test specimens D1 to D3, test specimens E1 to E3, test specimens F1 to F3, and test specimens G1 to G3. Here, test specimens D1 to D3, test specimens E1 to E3, test specimens F1 to F3, and test specimens G1 to G3 are test specimens made of a tile material with a planar shape of 45 mm × 45 mm for the construction member 20, and a cement hardened body 30 attached to the construction member 20, which is an adhesive made of mortar with a thickness of about 20 mm.

[0112] (Test Results - Third Removal Confirmation Test - Details of Test Results) Next, the details of the test results of the third removal confirmation test will be described. FIG. 10 is a diagram showing the test results of the third removal confirmation test. (a) is a diagram showing the relationship between the temperature of the second acid solution AL2 and the mass reduction amount of each test specimen, and (b) is a diagram showing the relationship between the temperature of the second acid solution AL2 and the titration concentration of the second acid solution AL2.

[0113] As shown in FIG. 10(a), for the mass reduction amounts of test specimens D1 to D3, test specimens E1 to E2, and test specimens F1 to F2, it was confirmed that the mass reduction amounts were larger compared to test specimens F3 and test specimens G1 to G3. From the mass reduction amounts of these test specimens D1 to D3, test specimens E1 to E2, and test specimens F1 to F2, it is speculated that if the temperature of the second acid solution AL2 is about 50°C to 90°C, the mass reduction amount will be 15 g or more.

[0114] Also, as shown in Fig. 10(b), the titration concentration of the second acid solution AL2 for the test specimens D1, E1, F1, and G1 is almost the same as the original concentration of 8.75 wt%, and the titration concentration of the second acid solution AL2 for the test specimens D2, E2, F2, and G2 is almost the same as the original concentration of 25 wt%. On the other hand, although the titration concentration of the second acid solution AL2 for the test specimens E3, F3, and G3 was almost the same as the original concentration of 35 wt%, it was confirmed that the titration concentration of the test specimen D3 was significantly lower than 35 wt% due to the evaporation of the components of the second acid solution AL2.

[0115] From the above, the effectiveness of immersing the construction member 20 in the second acid solution AL2 with an acid concentration of 8 wt% to 35 wt% and at about 50°C to 90°C was confirmed.

[0116] (Test Results - Fourth Removal Confirmation Test - Overview) Subsequently, the overview of the fourth removal confirmation test will be described.

[0117] The fourth removal confirmation test is a test for confirming the removal amount of the cement hardened body 30 in each test specimen under various test conditions (specifically, the conditions of the immersion period and the presence or absence of the removal operation of the cement hardened body 30).

[0118] The test method of this fourth removal confirmation test is arbitrary, but it is as follows. That is, first, the mass of each test specimen is measured using a known mass measuring instrument. Next, each test specimen is put into the corresponding second container 52 containing the second acid solution AL2 with an acid concentration of 35 wt% and at 80°C (specifically, an acid solution containing hydrochloric acid), and the test specimen is immersed for a predetermined period (for the test specimen H3 described later, the rubbing and washing of the test specimen H3 described later are performed a total of 4 times during and after the above immersion). Then, after the above immersion, the mass of each test specimen is measured again using the mass measuring instrument, and the mass reduction amount indicating the mass difference before and after immersion is calculated.

[0119] Here, regarding the immersion period of the second acid solution AL2, it is set to 15 minutes for the test piece H1 described later, 60 minutes for the test piece H2 described later, and 15 minutes × 4 times (i.e., a total immersion of 60 minutes) for the test piece H3 described later.

[0120] Also, regarding the test pieces used in the fourth removal confirmation test, they are divided into test piece H1 to test piece H3. Here, test piece H1 to test piece H3 are test pieces configured substantially the same as test piece D1.

[0121] (Test Results - Fourth Removal Confirmation Test - Details of Test Results) Next, the details of the test results of the fourth removal confirmation test will be described. FIG. 11 is a diagram showing the test results of the fourth removal confirmation test.

[0122] As shown in FIG. 11, for test piece H3, it was confirmed that the mass reduction amount was larger compared to test piece H1 and test piece H2. Specifically, it was confirmed that the mass reduction amount of test piece H3 was about 1.5 times that of test piece H2.

[0123] From the above, after immersing the construction member 20 in the second acid solution AL2 for about 15 minutes, the effectiveness of repeatedly removing the cement hardened body 30 from the construction member 20 by a predetermined removal method was confirmed.

[0124] (Effects of Embodiment) As described above, according to the embodiment, by drying the construction member 20 at a drying temperature below the firing temperature of the glaze contained in the surface film 22 of the construction member 20, a drying process for bringing the cement hardened body 30 into a completely dry state or an approximate state thereof, and after the drying process, an immersion process of immersing the construction member 20 in an acid solution are included. Therefore, compared with the prior art (a technique of drying a construction member at a drying temperature below the firing temperature of the construction member and then immersing it in an acid solution), while effectively removing the cement hardened body 30 from the construction member 20, discoloration of the surface film 22 of the construction member 20 can be suppressed, and the reusability of the construction member 20 can be enhanced.

[0125] In the drying process, since the construction member 20 is dried at a drying temperature of 100°C to less than 500°C, discoloration of the surface film 22 of the construction member 20 can be reliably avoided, and the reusability of the construction member 20 can be further enhanced.

[0126] In the drying process, since the construction member 20 is dried at a drying temperature of about 100°C for at least 3 hours or more, while reliably avoiding discoloration of the surface film 22 of the construction member 20, the state of the cement hardened body 30 can be surely made into an absolutely dry state or an approximate state thereof.

[0127] In the immersion process, since the construction member 20 is immersed in an acid solution at about 50°C to 90°C, while effectively removing the cement hardened body 30, the immersion process can be shortened.

[0128] Moreover, since it further includes a pre-immersion process in which the construction member 20 is immersed in an acid solution at room temperature after the drying process and before the immersion process, the removal of the cement hardened body 30 in the immersion process can be promoted, and the immersion process can be further shortened.

[0129] 〔III〕Modifications to the Embodiment As described above, the embodiments of the present invention have been described. However, the specific configurations and means of the present invention can be arbitrarily modified and improved within the scope of the technical idea of each invention described in the claims. Hereinafter, such modifications will be described.

[0130] (Regarding the problems to be solved and the effects of the invention) First, the problems to be solved by the invention and the effects of the invention are not limited to the above-described content. According to the present invention, it is also possible to solve problems not described above or to exhibit effects not described above. Further, it may solve only some of the described problems or exhibit only some of the described effects.

[0131] (Regarding shape, numerical value, structure, time series) Regarding the components exemplified in the embodiments and the drawings, with respect to the shape, numerical values, or the structure or temporal interrelationship of a plurality of components, arbitrary modifications and improvements can be made within the scope of the technical idea of the present invention.

[0132] (Regarding the acid concentration of the acid solution) In the above embodiment, it has been described that the acid concentration of the acid solution (specifically, the first acid solution AL1 and the second acid solution AL2) is set to about 3% by weight to 35% by weight, but it is not limited thereto. For example, when it is acceptable that the period required for removing the cement hardened body 30 is longer compared to the above embodiment, it may be set to less than 3% by weight. Alternatively, it may be set to a concentration exceeding 35% by weight.

[0133] (Regarding the method for removing the cement hardened body) In the above embodiment, it has been described that the method for removing the cement hardened body 30 includes a preparation step and a pre-immersion step, but it is not limited thereto. For example, when the construction member 20 and the cement hardened body 30 have already been removed from the building body 10, the preparation step may be omitted. Alternatively, when the cement hardened body 30 is made of a material that is easily removable from the construction member 20, the pre-immersion step may be omitted.

[0134] Also, in the above embodiment, in the drying step, it has been described that the construction member 20 is dried at a drying temperature of about 100°C to 700°C, but it is not limited thereto. For example, the construction member 20 may be dried at a drying temperature of less than 100°C, and as an example, it may be dried at a drying temperature of about 50°C to 90°C.

[0135] Also, in the above embodiment, in the immersion step, it has been described that the construction member 20 is immersed in an acid solution at about 50°C to 90°C, but it is not limited thereto. For example, the construction member 20 may be immersed in an acid solution at a temperature lower than 50°C, and as an example, it may be immersed in an acid solution at room temperature.

[0136] (Supplementary Note) The method for removing the cement hardened body according to Supplementary Note 1 is a removal method for removing the cement hardened body adhering to a construction member from the construction member. The method includes a drying step of drying the construction member at a drying temperature lower than the firing temperature of the glaze contained in the surface film of the construction member to make the cement hardened body in an absolutely dry state or an approximate state thereof, and an immersion step of immersing the construction member in an acid solution after the drying step.

[0137] The method for removing the cement hardened body according to Supplementary Note 2 is the method for removing the cement hardened body according to Supplementary Note 1, wherein in the drying step, the construction member is dried at the drying temperature of from 100°C to less than 500°C.

[0138] The method for removing the cement hardened body according to Supplementary Note 3 is the method for removing the cement hardened body according to Supplementary Note 2, wherein in the drying step, the construction member is dried at the drying temperature of about 100°C for at least 3 hours or more.

[0139] The method for removing the cement hardened body according to Supplementary Note 4 is the method for removing the cement hardened body according to any one of Supplementary Notes 1 to 3, wherein in the immersion step, the construction member is immersed in the acid solution at about 50°C to 90°C.

[0140] The method for removing the cement hardened body according to Supplementary Note 5 is the method for removing the cement hardened body according to any one of Supplementary Notes 1 to 4, and includes a pre-immersion step of immersing the construction member in the acid solution at room temperature after the drying step and before the immersion step.

[0141] (Effect of Supplementary Note) According to the method for removing a cement hardened body described in Supplementary Note 1, by drying the construction member at a drying temperature lower than the firing temperature of the glaze contained in the surface film of the construction member, a drying step of bringing the cement hardened body into an absolutely dry state or an approximate state thereof, and after the drying step, an immersion step of immersing the construction member in an acid solution are included. Therefore, compared with the prior art (the technique of drying the construction member at a drying temperature equal to or lower than the firing temperature of the construction member and then immersing it in an acid solution), while effectively removing the cement hardened body from the construction member, discoloration of the surface film of the construction member can be suppressed, and the reusability of the construction member can be enhanced.

[0142] According to the method for removing a cement hardened body described in Supplementary Note 2, in the drying step, since the construction member is dried at a drying temperature of from 100°C to less than 500°C, it is possible to surely avoid the occurrence of discoloration of the surface film of the construction member, and the reusability of the construction member can be further enhanced.

[0143] According to the method for removing a cement hardened body described in Supplementary Note 3, in the drying step, since the construction member is dried at a drying temperature of about 100°C for at least 3 hours or more, while surely avoiding the occurrence of discoloration of the surface film of the construction member, the state of the cement hardened body can be surely brought into an absolutely dry state or an approximate state thereof.

[0144] According to the method for removing a cement hardened body described in Supplementary Note 4, in the immersion step, since the construction member is immersed in an acid solution at about 50°C to 90°C, while effectively removing the cement hardened body, the immersion step can be shortened.

[0145] According to the method for removing a cement hardened body described in Supplementary Note 5, further including a pre-immersion step of immersing the construction member in an acid solution at normal temperature after the drying step and before the immersion step, the removal of the cement hardened body in the immersion step can be promoted, and the immersion step can be further shortened.

Explanation of Reference Numerals

[0146] 1 Body 10 Body Main Body 20 Construction Member 21 Construction material body 22 Surface film 30 Cement hardened body 31 Base part 32 Attachment part 41 Drying device 42 First container 51 Heating device 52 Second container 53 Brush 54 Third container AL1 First acid solution AL2 Second acid solution W Water

Claims

1. A removal method for removing a cement hardened body adhering to a construction material from the construction material, comprising: a drying step of drying the construction material at a drying temperature lower than the firing temperature of the glaze contained in the surface film of the construction material, thereby bringing the cement hardened body into an absolutely dry state or an approximate state thereof; an immersion step of immersing the construction material in an acid solution after the drying step; in the drying step, the construction material is dried at the drying temperature of 100°C to less than 500°C; A method for removing a cement hardened body.

2. In the drying step, the construction material is dried at the drying temperature of about 100°C for at least 3 hours or more. The method for removing a cement hardened body according to Claim 1.

3. In the immersion step, the construction material is immersed in the acid solution at about 50°C to 90°C. The method for removing a cement hardened body according to Claim 1 or 2.

4. A removal method for removing a cement hardened body adhering to a construction material from the construction material, comprising: a drying step of drying the construction material at a drying temperature lower than the firing temperature of the glaze contained in the surface film of the construction material, thereby bringing the cement hardened body into an absolutely dry state or an approximate state thereof; an immersion step of immersing the construction material in an acid solution after the drying step; a pre-immersion step of immersing the construction material in an acid solution at room temperature after the drying step and before the immersion step; A method for removing a cement hardened body.

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