JP2016199458A - Cement hardened body removal method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cement hardened body removal method which enables the cement hardened body adhered to an adhered building material to be easily removed and furthermore enables the labor, time and cost required for the removal to be reduced and the possibility of breakage of the adhered building material to be reduced.SOLUTION: The cement hardened body removal method is a method for removing a mortar 3 from an adhered building material 4 to which the mortar 3 is adhered, and includes a removal step of placing the adhered building material 4 under a cement hardened body removal environment for removing mortar 3 from adhered building material 4. For example, the cement hardened body removal environment includes an acid environment comprising an acid solution 6 into which at least a portion of the mortar 3 adhered to the adhered building material 4 can be immersed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for removing a cured cement body.

  Conventionally, a structure in which bricks are attached to a concrete frame forming an outer wall of a building via a base mortar, a tension mortar, or the like (hereinafter referred to as a hardened cement body) is used (for example, see Patent Document 1). ). Here, in the renovation work of a building, a method of once removing a brick from such a building and reattaching the removed brick to the wall after completion of the renovation work is performed. According to such a method, it is possible not only to maintain the original design, but also to fire the brick as compared with the method of using the newly fired brick and the method of pasting the brick-like print on the wall surface. Costs and print creation costs can be reduced.

  However, when the brick is once removed in the above-described renovation work, the above-mentioned cement cured body may adhere to the back side surface of the removed brick. In order to reuse the brick, this cement cured body Had to be removed from the back side of the brick. Specifically, this removal method is a technique in which a skilled person removes the hardened cement adhering to the back side of the brick by cutting it one by one using a tool such as a polishing machine. .

JP-A-11-210116

  However, the above-described method of cutting and removing each piece using a tool not only requires skill but also may require a lot of labor, time, and cost. It was. Further, since the cutting operation is performed using a polishing machine or the like, there is a possibility that the brick itself is damaged. Accordingly, it is possible to easily remove the hardened cement adhering to the brick, reduce the labor, time and cost required for the removal, and reduce the possibility of the brick being damaged. There was a need for a method that could do this.

  The present invention has been made in view of the above, and it is possible to easily remove the hardened cement adhering to the adhering building material (corresponding to the above brick), and the labor, time, and time required for the removal. An object of the present invention is to provide a method for removing a hardened cement body that can reduce the cost and can reduce the possibility of damage to an attached building material.

  In order to solve the above-described problems and achieve the object, the method of removing a hardened cement body according to claim 1 is a method of removing the hardened cement body from the attached building material to which the hardened cement body has adhered. And a removing step of disposing the adhered building material under a cement cured body removing environment for removing the cement cured body from the adhered building material.

  The method for removing a hardened cement body according to claim 2 is the method for removing a hardened cement body according to claim 1, wherein the environment for removing the hardened cement body immerses at least a part of the hardened cement body adhering to the attached building material. Includes an acid environment with possible acid solutions.

The method for removing a cured cement body according to claim 3 is the method for removing a cured cement body according to claim 2, wherein the adhering building material is immersed in the acid solution so as to satisfy the following formula (1) in the acid environment. To do.
Σ [i = 1 ton] (v _i L _i / X) [mol / g] ≧ 5.0 × 10 ⁻³ [mol / g] (1)
(here,
i: number of times the acid solution is exchanged or added,
n: total number of exchange or addition of acid solution,
M _i : hydrogen molar concentration [mol / L] of the acid solution in the i th exchange or addition,
L _i : Volume of acid solution [L] at the i th exchange or addition,
X: Weight of cured cement adhering to adhering building material [g])

The method for removing a hardened cement body according to claim 4 is the method for removing a hardened cement body according to claim 3, wherein the hydrogen molar concentration M _i of the acid solution in the i-th exchange or addition is expressed by the following formula (2): Fulfill.
M _i [mol / L] ≦ 100 / M _w [mol / L] (2)
(here,
M _w : molecular weight of the acid substance)

  The method for removing a hardened cement body according to claim 5 is the method for removing a hardened cement body according to any one of claims 2 to 4, wherein after the removing step, the surface of the adhering building material is washed and the adhering material is removed. A cleaning step of removing residual salt of the acid solution adhering to the surface of the building material.

  The method for removing a hardened cement body according to claim 6 is the method for removing a hardened cement body according to any one of claims 2 to 5, wherein the acid solution attached to a surface of the attached building material after the removing step. A detection step of detecting residual salts of

  The method for removing a hardened cement body according to claim 7 is the method for removing a hardened cement body according to any one of claims 1 to 6, wherein the environment for removing the hardened cement body is the cement hardened material attached to the attached building material. A heating environment including heating means capable of heating at least a part of the body is included.

The method for removing a hardened cement body according to an eighth aspect is the method for removing a hardened cement body according to the seventh aspect, wherein the attached building material is heated so as to satisfy the following formula (3) in the heating environment.
500 [° C.] ≦ T ≦ Ts [° C.] (3)
(here,
T: Heating temperature [° C]
Ts: Firing temperature of attached building materials [° C.])

  According to the method for removing a hardened cement body according to claim 1, the hardened cement body is removed by an extremely simple method of placing the adhering building material under a cement hardened body removal environment, and a manual operation by a person having skill in the art. It is possible to easily remove the hardened cement adhering to the adhering building material without needing it, and it is possible to reduce the labor, time and cost required for the removal, and possible damage to the adhering building material. Can be reduced.

  According to the method for removing a hardened cement body according to claim 2, since at least a part of the hardened cement body is immersed in the acid solution, the hardened cement body can be removed by dissolving in the acid solution, and the cement can be obtained very easily. It becomes possible to remove the cured body.

According to the method for removing a hardened cement body according to claim 3, the adhering building material is immersed in an acid solution so as to satisfy the following formula (1), so that the hardened cement body can be removed manually. It becomes possible to dissolve the cured body.
Σ [i = 1 ton] (M _i L _i / X) [mol / g] ≧ 5.0 × 10 ⁻³ [mol / g] (1)
(here,
i: number of times the acid solution is exchanged or added,
n: total number of exchange or addition of acid solution,
M _i : hydrogen molar concentration [mol / L] of the acid solution in the i th exchange or addition,
L _i : Volume of acid solution [L] at the i th exchange or addition,
X: Weight of cured cement adhering to adhering building material [g])

According to the method for removing a hardened cement body according to claim 4, the attached building material is immersed in the acid solution so that the hydrogen molar concentration M _i of the acid solution in the i-th exchange or addition satisfies the following formula (2). Therefore, the hardened cement body can be removed using an acid solution that does not correspond to a deleterious substance, and safe and easy removal is possible.
M _i [mol / L] ≦ 100 / M _w [mol / L] (2)
(here,
M _w : molecular weight of the acid substance)

  According to the method for removing a hardened cement body according to claim 5, after the removing step, the surface of the adhered building material is washed and the residual salt of the acid solution adhered to the surface of the adhered building material is removed. It is possible to prevent the residual salt from inhibiting the adhesion to the wall surface when reused.

  According to the method for removing a hardened cement body according to claim 6, since the residual salt of the acid solution adhering to the surface of the attached building material is detected after the removing step, the residual salt can be removed by confirming the presence or absence of the residual salt. Further, it becomes possible to further prevent the residual salt from inhibiting the adhesion to the wall surface when the attached building material is reused for the wall surface.

  According to the method for removing a hardened cement body according to claim 7, since at least a part of the hardened cement body is heated, the hardened cement body can be weakened by a composition change due to heating, and the hardened cement body can be very easily performed. Can be removed.

According to the method for removing a hardened cement body according to claim 8, since the attached building material is heated so as to satisfy the following formula (3), the hardened cement body can be weakened until it can be easily removed by manual work. The hardened cement can be removed very easily, and the temperature can be kept at a level that does not affect the attached building material. This can be prevented.
500 [° C.] ≦ T ≦ Ts [° C.] (3)
(here,
T: Heating temperature [° C]
Ts: Firing temperature of attached building materials [° C.])

It is sectional drawing which shows the wall surface of the building which concerns on Embodiment 1 of this invention. It is a figure which shows the adhesion building material in the removal process of the cement hardening body removal method which concerns on Embodiment 1 of this invention. It is a figure which shows the result of the experiment A. It is a figure which shows the result of the hydrochloric acid in Experiment B, Comprising: Fig.4 (a) is a photograph which shows the mortar block after 40 days immersion, FIG.4 (b) is the hydrogen substance amount [mol / g] of hydrochloric acid per 1 g of mortar. It is a table | surface which shows. It is a figure which shows the result of hydrochloric acid in Experiment B, Comprising: It is a figure which shows the solubility [%] of a mortar block. FIG. 6A is a diagram showing the results of nitric acid in Experiment B, FIG. 6A is a photograph showing a mortar block after immersion for 40 days, and FIG. 6B is a hydrogen substance amount of nitric acid per 1 g of mortar [mol / g]. It is a table | surface which shows. It is a figure which shows the result of the sulfuric acid in Experiment B, Comprising: Fig.7 (a) is a photograph which shows the mortar block after 40-day immersion, FIG.7 (b) is the hydrogen substance amount [mol / g] of the sulfuric acid per mortar. It is a table | surface which shows. FIG. 8A is a diagram showing the results of citric acid in Experiment B, FIG. 8A is a photograph showing a mortar block after immersion for 40 days, and FIG. 8B is a hydrogen substance amount of citric acid per 1 g of mortar [mol / g]. FIG. 6 is a diagram showing the results of Experiment C. It is a table | surface which shows the adhesion conditions of calcium chloride. It is a graph which shows the adhesive strength [N / mm < ² >] of sticking M. FIG. It is a graph which shows the interface fracture rate [%] of sticking M. It is a graph which shows the adhesive strength [N / mm < ² >] of exterior MS * EP. It is a graph which shows the interface fracture rate [%] of exterior MS and EP. It is a graph which shows the adhesive strength [N / mm < ² >] of MS for interior use. It is a graph which shows the interface fracture rate [%] of interior MS. It is a table | surface which shows the outline | summary of the test body of experiment D-2. It is a table | surface which shows the adhesiveness confirmation test result regarding washing | cleaning process (i). It is a table | surface which shows the adhesiveness confirmation test result regarding a cleaning process (ii). It is a table | surface which shows the conditions of the washing | cleaning regarding experiment D-3. It is a graph which shows the test result (hydrochloric acid immersion) of experiment D-3. It is a graph which shows the test result (calcium chloride immersion) of experiment D-3. It is a list of the test body regarding experiment D-4. It is a graph which shows the chlorine ion density | concentration measurement result regarding Experiment D-4 (water immersion after hydrochloric acid immersion, no replacement of water). It is a graph which shows the chlorine ion density | concentration measurement result (Experiment D-4 water immersion after calcium chloride immersion, no replacement of water). It is a graph which shows the chlorine ion density | concentration measurement result regarding Experiment D-4 (with water immersion after hydrochloric acid immersion, and the replacement of water). It is a graph which shows the chlorine ion density | concentration measurement result (Experiment D-4 water immersion after calcium chloride immersion, with water replacement). It is a figure which shows the adhesion building material in the removal process of the cement hardening body removal method which concerns on Embodiment 2 of this invention. It is a figure which shows the result of experiment F. FIG.

  Hereinafter, an embodiment of a method for removing a hardened cement according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited by this embodiment.

[Basic concept of the embodiment]
First, the basic concept of the embodiment will be described. Each embodiment generally relates to a method for removing a hardened cement body, which removes the hardened cement body from an attached building material to which the hardened cement body has adhered. The “adhesive building material” is a concept that includes various building materials to which a hardened cement body has adhered. For example, in each embodiment, it is assumed that the building material is a brick that is attached to the outer peripheral surface of a building. explain. In addition, the use of the attached building material from which the hardened cement body has been removed by this method of removing the hardened cement body is arbitrary. For example, it can be reused in the same building or a different building from which the attached building material was originally attached. They may be used for other purposes. However, in each embodiment, it demonstrates supposing the case where it reuses for the same building.

[Specific contents of the embodiment]
Next, specific contents of the embodiment will be described.

(Embodiment 1)
First, the first embodiment will be described. This Embodiment 1 is a form regarding the method of removing a cement hardening body from an adhesion building material roughly by immersing an adhesion building material in an acid solution.

(Constitution)
First, the structure of the building 1 to which the hardened cement body removal method according to the first embodiment is applied will be described. FIG. 1 is a cross-sectional view showing a wall surface of a building 1 according to the first embodiment. As shown in FIG. 1, the wall surface of the building 1 includes a frame 2, a mortar 3, and an attached building material 4. In the present embodiment, the “wall surface” of the building 1 is described as being an outer wall, but the same structure can be applied to a pillar, a beam, an inner wall, or the like without being limited to the outer wall.

(Configuration-enclosure)
The frame 2 is a concrete structure that constitutes the wall surface of the building 1. The housing 2 is composed of, for example, a wall, a pillar, or the like of the building 1 and is a portion to which the attached building material 4 is attached. In the first embodiment, the case 2 is described as being made of concrete. However, the present invention is not limited to this, and the case 2 of any material can be applied. Further, the shape and size of the housing 2 are also arbitrary.

(Composition-Mortar)
The mortar 3 is a known cement hardened body interposed between the housing 2 and the attached building material 4. The mortar 3 is generally configured to include a base mortar 3a and a tension mortar 3b.

  The ground mortar 3a is a mortar for performing unevenness correction of the housing 2. The foundation mortar 3a is a mortar that is directly applied to the outer surface of the casing 2, and improves the design at the time of finishing by correcting the unevenness of the casing 2. In addition, since the well-known thing can be employ | adopted about the thickness and specific kind of the base mortar 3a, detailed description is abbreviate | omitted.

  The sticking mortar 3b is a mortar for sticking the adhering building material 4 to the base mortar 3a. This sticking mortar 3b is a mortar that is applied to the surface of the base mortar 3a, and a mortar having sufficient adhesive strength to bond the attached building material 4 to the base mortar 3a is applied. In addition, since the well-known thing can be employ | adopted about the thickness and specific kind of the tension mortar 3b, detailed description is abbreviate | omitted.

(Configuration-Adhering building materials)
The attached building material 4 is a building material attached to the outer surface of the housing 2. A plurality of the adhering building materials 4 are arranged in the vertical and horizontal directions along the wall surface, and are adhered to the outside of the tensioning mortar 3b. Here, although the shape and material of each adhesion building material 4 are arbitrary, in this Embodiment 1, although demonstrated as what is a well-known brick of a substantially rectangular parallelepiped shape, various building materials (tile etc.) other than a brick are demonstrated. ) Can be used. Moreover, although the shape of this adhesion | attachment building material 4 is arbitrary, in this Embodiment 1, the surface (henceforth front side surface) of the side exposed outside is flat among the surfaces of the adhesion | attachment building material 4 shown in FIG. A plurality of groove portions 4a are formed on the surface (hereinafter referred to as the back side surface) of the attached building material 4 that is attached to the attaching mortar 3b. This groove part 4a is for increasing the adhesive force of the adhesion building material 4 with respect to the tensioning mortar 3b by producing a anchoring effect between the adhesion building material 4 and the tensioning mortar 3b. The mortar 3b has a tension. In addition, when it is not necessary to particularly distinguish these front side surfaces and back side surfaces, they are simply referred to as “surface” of the attached building material 4 and will be described below.

(Cemented body removal method)
Next, the method for removing a hardened cement body according to the first embodiment will be described.

(Cement hardened body removal method-attached building material acquisition process)
First, the adhesion building material acquisition process which acquires the adhesion building material 4 to which the cement hardening body adhered is performed. The “cured cement” is a cement-based material attached to the attached building material 4 and is a concept including the mortar 3 such as the base mortar 3a and the tension mortar 3b in the first embodiment. Here, although the specific method of acquiring the adhesion building material 4 in this way is arbitrary, in this Embodiment 1, by cutting | disconnecting the base | substrate mortar 3a and the tension mortar 3b with a wire saw along a wall surface , Will be described as being acquired. It should be noted that the method is not limited to such a method of intentionally removing, and the attached building material 4 that is accidentally removed due to, for example, seismic motion or aging of the wall surface may be acquired.

(Cement cured body removal method-removal process)
Next, the removal process which arrange | positions the adhesion building material 4 under the cement hardening body removal environment which removes a cement hardening body from the adhesion building material 4 is implemented. FIG. 2 is a diagram showing the attached building material 4 during the removing step of the method for removing a hardened cement body according to the first embodiment. The “hardened cement body removal environment” is an environment in which the hardened cement body can be removed from the attached building material 4, and in the first embodiment, at least a part of the mortar 3 attached to the attached building material 4 is immersed. An acid environment with possible acid solution 6.

  Thus, the specific method of immersing the adhering building material 4 in the acid solution 6 is arbitrary, but in the present embodiment 1, as shown in FIG. 2, the inside of the container 5 is filled with the acid solution 6, A plurality of attached building materials 4 are immersed in the acid solution 6. In addition, although the number of adhesion | attachment building materials 4 is arbitrary, in FIG. 2, what put three adhesion | attachment building materials 4 with respect to one container 5 is illustrated.

Below, the principle which can remove the mortar 3 from the adhesion | attachment building material 4 by immersing in the acid solution 6 is demonstrated. That is, since the mortar 3 contains Ca (OH) ₂ or CaCO ₃ and the attached building material 4 is usually a substance having high acid resistance, when the mortar 3 and the attached building material 4 are immersed in the acid solution 6 at the same time, the Ca (OH) ₂ is neutralized and CaCO ₃ is dissolved in the acid solution 6 by the weak acid release reaction, and only the mortar 3 is dissolved. Thus, only the adhesion | attachment building material 4 can be taken out because the mortar 3 melt | dissolves. Note that it is not always necessary to dissolve the entire mortar 3, and it is sufficient to dissolve only a part of the mortar 3. That is, by dissolving only a part, the volume of the mortar 3 can be reduced, and the contact surface between the mortar 3 and the attached building material 4 can be weakened. Can be easily peeled off.

  Here, the amount of the acid solution 6 is arbitrary as long as at least a part of the mortar 3 can be immersed, and the adhering building material 4 may not be immersed in the acid solution 6, but Embodiment 1 , An excessive amount of acid solution 6 is used so that both the adherent building material 4 and the mortar 3 are completely immersed.

  Moreover, the kind of acid of the acid solution 6 is arbitrary as long as it can react with at least a part of the components of the mortar 3 to dissolve the mortar 3, and examples thereof include hydrochloric acid, nitric acid, sulfuric acid, citric acid, and iodide. Hydroacid, 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 and the like can be used. Hereinafter, the case where hydrochloric acid is used as the acid solution 6 will be described as an example.

(Cemented body removal method-cleaning process)
The cleaning step is a step of cleaning the surface of the attached building material 4 after the removing step and removing the residual salt of the acid solution 6 attached to the surface (particularly the back side surface) of the attached building material 4. That is, a residual salt (for example, calcium chloride when hydrochloric acid is used for the acid solution 6) from the reaction between the acid solution 6 and the mortar 3 is attached to the surface of the attached building material 4, and this residual salt is If the attached building material 4 is reused on the wall surface while adhering, there is a possibility that it will float from the wall surface due to poor adhesion or the like. Therefore, in order to remove the residual salt from the surface of the attached building material 4, the cleaning process is performed. Here, the specific method of cleaning is arbitrary, and for example, cleaning may be performed by rubbing the attached building material 4 with a brush or the like while exposing the attached building material 4 to running water, but more preferably, the attached building material 4 may be immersed in water. . Details of this point will be described in an experiment D-4 of an example described later.

(Cement cured body removal method-detection process)
The detection step is a step of detecting the residual salt of the acid solution 6 attached to the surface of the attached building material 4. That is, since the above-mentioned calcium chloride, which is a residual salt of hydrochloric acid, is colorless and transparent, it cannot be easily confirmed by visual inspection or the like whether or not calcium chloride has been reliably removed even after the attached building material 4 has been washed. . Therefore, by performing such a detection step, it can be confirmed whether or not the residual salt (calcium chloride) attached to the attached building material 4 can be removed from the attached building material 4 in the above-described cleaning step.

  A specific method for such detection is arbitrary, but in the first embodiment, a method of spraying an aqueous silver nitrate solution is employed. Specifically, the presence or absence of calcium chloride is confirmed by spraying a silver nitrate aqueous solution by spraying or the like on the adhered building material 4 after washing, and confirming the presence or absence of a white precipitate generated based on the reaction between the silver nitrate aqueous solution and calcium chloride. Check. In addition, such a method is only an example, and other methods include, for example, immersing the attached building material 4 in a predetermined volume of water, and using a known salinity meter, a detection tube, or the like to measure the salt concentration of the soaked water. There are a method of confirming by using the method, a method of confirming the surface chlorine concentration by fluorescent X-ray analysis, and the like. By performing the detection step in this manner, it is possible to confirm the presence or absence of calcium chloride, and it is possible to prevent forgetting to wash or to improve the washing method.

(Example)
Then, the Example of the cement hardening body removal method which concerns on this Embodiment 1 is demonstrated. This example relates to an experiment for specifying optimum conditions for removing a hardened cement in the method of removing a hardened cement.

(About Experiment A)
First, Experiment A was performed to confirm the relationship between the number of days immersed in the acid solution 6 and the remaining amount of mortar 3. This experiment A is an experiment in which a 25 mm cubic mortar block is immersed in four types of hydrochloric acid having different hydrogen molar concentrations for 40 days, and the amount of change of the mortar 3 due to the immersion is confirmed. FIG. 3 is a diagram showing the results of Experiment A. In FIG. 3, the horizontal axis indicates the number of days of immersion [days], and the vertical axis indicates the residual amount [g] of the mortar 3. The hydrogen molar concentrations [mol / L] of the four types of hydrochloric acid used were 0.1 [mol / L], 0.5 [mol / L], 1.0 [mol / L], and 2.0, respectively. [mol / L] and the amount of hydrochloric acid is 200 mL in all cases.

  As shown in FIG. 3, in any hydrogen molar concentration hydrochloric acid, it can be seen that the residual amount of mortar 3 decreases exponentially as the day increases and hardly changes on the 40th day. . It can also be seen that the amount of change and the rate of change of the mortar 3 increase as the acid with a higher hydrogen molar concentration is used.

(About Experiment B)
Subsequently, Experiment B was performed in order to examine the characteristics of each type of acid. In this experiment B, 25 mm cubic mortar blocks were immersed in hydrochloric acid, nitric acid, sulfuric acid, and citric acid, which are four different types of acids, for 40 days, respectively, and the transition of the state of the mortar block was confirmed. FIG. 4 is a diagram showing the results of hydrochloric acid in Experiment B. FIG. 4 (a) is a photograph showing a mortar block after immersion for 40 days, and FIG. 4 (b) is a hydrogen substance amount of hydrochloric acid per 1 g of mortar [ mol / g]. In addition, the vertical axis | shaft in Fig.4 (a) is hydrogen molar concentration [mol / L] of an acid, and a horizontal axis is the solution amount [mL] of the acid to immerse. Further, the table shown in FIG. 4B shows the items “0.1 [mol / L]”, “0.5 [mol / L]”, “ 1.0 [mol / L] ”,“ 2.0 [mol / L] ”and items“ 50 mL ”,“ 100 mL ”,“ 200 mL ”, and“ 500 mL ”in the column indicating the amount of acid solution [mL] The amount of hydrogen substance [mol / g] of acid per gram of mortar is stored as information corresponding to the combination of each item of the matrix. In addition, each mortar block of FIG. 4A and the information corresponding to the combination of each item of the matrix of FIG. 4B are shown by the positional relationship corresponding to each other. The explanation of FIG. 4 is the same in FIGS. 6 to 9 described later except for the type of acid.

  FIG. 5 is a diagram showing the results of hydrochloric acid in Experiment B and showing the solubility [%] of the mortar block. Each item in the matrix in FIG. 5 corresponds to each item in the matrix in FIG. As information corresponding to the combination of each item in the matrix of FIG. 5, the solubility [%] of the mortar block on the 40th day after immersion is stored. Here, the “solubility” is obtained by dividing the weight reduction amount of the mortar block after the immersion by the weight of the mortar block before the immersion and expressing it as a percentage.

  As shown in FIGS. 4 and 5, the mortar block can be dissolved by immersing the mortar block in hydrochloric acid. In addition, as the solution amount or hydrogen molar concentration of hydrochloric acid is increased, it is possible to dissolve more mortar blocks. In particular, when the hydrogen molar concentration is 2.0 mol / L when the solution amount is 500 mL, the solution amount is 500 mL. When the hydrogen molar concentration was 1.0 mol / L, and when the solution amount was 200 mL and the hydrogen molar concentration was 2.0 mol / L, the mortar block was 100% dissolved.

  FIG. 6A is a diagram showing the results of nitric acid in Experiment B, FIG. 6A is a photograph showing a mortar block after immersion for 40 days, and FIG. 6B is a hydrogen substance amount of nitric acid per 1 g of mortar [mol / g]. It is a table | surface which shows. FIG. 7 is a diagram showing the results of sulfuric acid in Experiment B, in which FIG. 7 (a) is a photograph showing a mortar block after immersion for 40 days, and FIG. 7 (b) is a hydrogen substance amount of sulfuric acid per 1 g of mortar [ mol / g]. FIG. 8 is a diagram showing the results of citric acid in Experiment B, FIG. 8 (a) is a photograph showing a mortar block after immersion for 40 days, and FIG. 8 (b) is a hydrogen substance of citric acid per gram of mortar. It is a table | surface which shows quantity [mol / g]. As shown in FIGS. 6 to 8, it can be seen that even when nitric acid, sulfuric acid, or citric acid is used, the mortar block can be dissolved similarly to hydrochloric acid. However, when sulfuric acid is used, the calcium sulfate generated as precipitates, and when citric acid is used, calcium citrate or calcium hydrogen citrate covers the surface of the mortar 3 as precipitates. And the reaction between the mortar 3 and the reaction may be delayed.

(About Experiment C)
Subsequently, an experiment C was performed in order to specify conditions under which the mortar 3 was easily peeled off from the attached building material 4. In Experiment C, a 25 mm cubic mortar block was immersed for 40 days in acid solutions 6 having different hydrogen molar concentrations and different solution amounts, and then the remaining mortar block was taken out and struck with a pick and a hammer for destruction. This is an experiment to count the number of hits required to destroy. FIG. 9 is a diagram showing the results of Experiment C. Here, when the mortar 3 remaining on the back side surface of the attached building material 4 is removed by blow, the number of blows required for removal is less than the reference number in consideration of work efficiency and the possibility of damage to the attached building material 4 main body. Is preferred. The “reference number” can be arbitrarily determined based on, for example, the strength of the attached building material 4. For example, in the first embodiment, the reference number is 10 times.

Here, referring to FIG. 9, the acid that can be dissolved to the extent that the mortar 3 can be removed by hitting less than the standard number of times is the acid of the item that is hatched, and these acids are all shown in FIG. 5. Is an acid in which 50% or more of the mortar 3 is dissolved. The corresponding items in FIG. 5 are similarly hatched. That is, in order to suppress the number of hits to the reference number (10 times) or less, it is necessary to dissolve 50% or more of the mortar 3 with an acid. Here, referring to FIG. 4B, the amount of hydrogen substance of acid per mortar of an acid in which 50% or more of mortar 3 is dissolved (corresponding items are hatched in the same manner as in FIG. 5). It can be seen that (ML / X [mol / g]) is larger than 5.0 × 10 ⁻³ [mol / g]. Therefore, the following formula (1) is established as a suitable condition for removing the mortar 3 from the attached building material 4.
ML / X [mol / g] ≧ 5.0 × 10 ⁻³ [mol / g] (1)
(here,
M: hydrogen molar concentration of the acid solution 6 [mol / L],
L: Volume of acid solution 6 [L],
X: Weight of mortar 3 adhering to adhering building material 4 [g])

In each experiment described above, the mortar 3 is immersed in the acid solution 6 only once. However, by replacing the acid solution 6 a plurality of times, the mortar 3 is immersed in a different acid solution 6 a plurality of times. Alternatively, the acid solution 6 may be continuously added by flowing the acid solution 6 into the container 5. Therefore, in consideration of such exchange and addition, the following formula (1) ′ is established based on the above formula (1).
Σ [i = 1 ton] (M _i L _i / X) [mol / g] ≧ 5.0 × 10 ⁻³ [mol / g] (1) ′
(here,
i: number of times the acid solution 6 is exchanged or added,
n: total number of times the acid solution 6 is exchanged or added,
M _i : Hydrogen molar concentration [mol / L] of the acid solution 6 in the i-th exchange or addition,
L _i : Volume [L] of the acid solution 6 in the i th exchange or addition,
X: Weight of mortar 3 adhering to adhering building material 4 [g])

Here, the higher the hydrogen molar concentration of the acid solution 6 is, the easier it is to satisfy the above formula (1) and (1) ′, but the hydrogen molar concentration of the acid solution 6 is large and the deleterious conditions (10 wt% ), It becomes difficult to handle safely when working. Therefore, in order to use the acid solution 6 that does not correspond to the deleterious condition (10 wt%), it is preferable to use the acid solution 6 that satisfies the following conditions.
M _i [mol / L] ≦ 100 / M _w [mol / L] (2)
(here,
M _w : molecular weight of the acid substance)

(About Experiment D)
Subsequently, in order to investigate the influence of the residual salt of the acid solution 6 on the adhesion to the wall surface when the attached building material 4 is reused, Experiment D was performed. In this experiment D, the residual salt is generally adhered to the back side of the tile, which is the attached building material 4, and then the tile is adhered to the concrete plate with an adhesive or mortar. This is an experiment for measuring strength and interface fracture rate.

Specifically, first, calcium chloride was adhered to the back side of a new tile by various methods to prepare tiles having different calcium chloride adhesion amounts. FIG. 10 is a table showing the adhesion conditions of calcium chloride. Here, “brush coating” is a brush that is sufficiently dipped in a calcium chloride aqueous solution, applied to the tile back side from end to end, and dried. The number of times in the table indicates the number of repetitions. “Immersion” means that the tile is immersed in an aqueous calcium chloride solution for 24 hours. “Wipe off” refers to a tile that is dipped in a calcium chloride aqueous solution and then taken out, and the surface solution is lightly wiped with a waste cloth. In the “cleaning treatment”, the tiles are washed with tap water immediately after being immersed in the calcium chloride aqueous solution, and then washed thoroughly with gold scourer. The “back side adhesion amount” is obtained by measuring the initial weight and the dry weight after calcium chloride adhesion for the levels A to F, and converting the difference into the weight per 1 cm ² of the tile back side. Here, the amount of calcium chloride remaining on the back side surface of the tile is A>B>C>D>E> F (= 0). Level E assumes a state in which the adhered calcium chloride is sufficiently removed by washing.

  Next, each level of tile was bonded to a 300 × 300 × 60 mm concrete plate with one type of mortar and two types of tile adhesives. As the mortar, a pre-prepared mortar for tile attachment (hereinafter referred to as “tension M”) was used by mixing with water in a manufacturer's standard composition. The elastic adhesive for tiles includes a modified silicone / epoxy resin elastic adhesive for exterior (hereinafter referred to as “MS / EP for exterior”) and a modified silicone resin elastic adhesive for interior (hereinafter referred to as “MS for interior”). 2 types) were used. After the tile adhesion, it was cured for 2 weeks in an environment of 23 ° C. and 50% RH.

  Next, as a tensile test, a 40 mm square tensile test attachment was bonded to the surface of the tile with an epoxy resin, and after curing, a cutter was put on the four sides of the attachment to the ground. Then, a tensile test was performed at a speed of 3 mm / min using a universal testing machine. At this time, the obtained maximum load value was divided by the adhesion area to calculate the adhesion strength. Further, the fracture surface of the test specimen was observed, and the “interfacial fracture rate between the tile and the adhesive or mortar” serving as a criterion for judging the adhesiveness from the adhesion area was recorded. The number of test bodies was 10 and the average value was calculated.

The results of Experiment D are shown in FIGS. FIG. 11 is a graph showing the adhesive strength [N / mm ² ] of the sticking M, and FIG. 12 is a graph showing the interface fracture rate [%] of the sticking M. FIG. 13 is a graph showing the adhesive strength [N / mm ² ] of the exterior MS / EP, and FIG. 14 is a graph showing the interfacial fracture rate [%] of the exterior MS / EP. FIG. 15 is a graph showing the adhesive strength [N / mm ² ] of the interior MS, and FIG. 16 is a graph showing the interface fracture rate [%] of the interior MS. In addition, the error bar in FIG. 11, FIG. 13, and FIG. 15 represents the range from the maximum value to the minimum value of the adhesive strength in the tensile test.

As shown in FIG. 11, with respect to the sticking M, an average adhesive strength of 1.0 N / mm ² or more was shown at all levels. Note that A and B, which have a large amount of calcium chloride attached, had slightly lower adhesive strength and a slightly higher interface fracture rate than other levels. In addition, there was a situation in which interface fracture occurred on the uneven protrusions on the back foot of the tile.

Further, as shown in FIG. 13, for the exterior MS / EP, the adhesion strength is highest for F without calcium chloride adhering, and the other is an average adhesion of 0.6 N / mm ² or more regardless of the adhesion amount. The strength was confirmed. However, as shown in FIG. 14, A and B with a large amount of calcium chloride adhered resulted in a high interfacial fracture rate.

  In addition, as shown in FIG. 15, with respect to the interior MS, there was a tendency for the adhesive strength to be lower as the amount of calcium chloride adhered was larger. Further, as shown in FIG. 16, except for the cleaned E, if the calcium chloride is adhered to the back side surface of the tile regardless of the amount of adhesion, the interfacial fracture rate was high.

  As shown in FIGS. 11 to 16 above, the sticking M is considered to have little influence on the adhesion due to the adhesion of calcium chloride from the results of the adhesive strength and the interface fracture rate. In addition, MS / EP for exterior use has a tendency to increase the interface fracture rate when there is much adhesion of calcium chloride, and there is a slight effect, but the adhesion can be secured by suppressing the amount of calcium chloride adhesion or washing. It is considered possible. The interior MS is more susceptible to adhesion inhibition due to residual salt than the sticking M and exterior MS / EP, but it is considered that the adhesion can be secured by sufficient cleaning. From the above, it is considered that adhesiveness can be secured by removing residual salts mainly composed of calcium chloride attached to the tiles by washing or the like. Therefore, by performing the cleaning process for cleaning the attached building material 4 as in the present embodiment, when the attached building material 4 is reused on the wall surface, the residual salt is prevented from inhibiting the adhesion to the wall surface. Is possible.

(About Experiment D-2)
Subsequently, Experiment D-2 was performed in order to identify a suitable cleaning process for residual salts mainly composed of calcium chloride attached to the attached building material 4. That is, it has been found that a salt containing calcium chloride as a main component remains on the back surface of the tile from which the mortar has been removed by acid dipping, which adversely affects adhesiveness when tiled. Therefore, in Experiment D-2, two types of cleaning methods for washing away this salt (washing the tile surface with water (hereinafter referred to as cleaning process (i) and water immersion cleaning of the tile (hereinafter referred to as cleaning process (ii))). And conducted an experiment to compare the adhesion of the tiles after each cleaning process.

Specifically, in the experiment D-2, first, the test specimen was immersed in 1 mol / L hydrochloric acid (a solution amount having a substance amount of 1.0 × 10 ⁻² mol or more per 1 g of mortar) for a predetermined period. After removing the mortar adhering to the tile, the mortar was removed from the acid solution, and the cleaning process (i) or the cleaning process (ii) was performed. In the washing process (i), specifically, washing was performed by rubbing with SUS gold scrubbing while running with tap water. In addition, the cleaning process (ii) is specifically performed by immersing in the same amount of water as the used hydrochloric acid for 21 days, replacing water on the 7th and 14th days, and washing the tiles with running water after immersion in water. Went.

  Next, the washed tile is dried, and then tiled on a concrete flat plate using three types of tile tensioning materials (the above-mentioned “Tension M”, “Exterior MS / EP”, “Interior MS”). Tensioned. FIG. 17 is a table showing an outline of the test specimen of Experiment D-2. As shown in FIG. 17, dismantling tiles taken from eight types of actual buildings were used as test specimens.

  The test specimen was cured for 2 weeks or more at 23 ± 2 ° C. and (50 ± 10) RH% after the construction, and then a tensile test jig was attached with an epoxy resin, and 3 mm / min using a universal testing machine. A tensile test was performed at a speed to calculate the tensile strength. After observing the fracture surface, the fracture position / breakage area ratio, which is a reference for judging the quality of the adhesion from the adhesion area, was recorded. The number of test specimens of the tensile test was 5 for the cleaning process (i) and 6 for the cleaning process (ii), and the average value was calculated for the tensile strength and the fracture area ratio. FIG. 18 is a table showing the adhesion confirmation test result regarding the cleaning process (i), and FIG. 19 is a table showing the adhesion confirmation test result regarding the cleaning process (ii).

In the tables of FIG. 18 and FIG. 19, the adhesive strength after the tensile test, the interface fracture rate (interface between the tile and the pasting material), and the main fracture locations are shown, respectively. In the cleaning process (i), a certain adhesive strength was confirmed in each of the pasting materials. However, in the exterior MS / EP and interior MS, the tile-side thin layer cohesive failure or tile in some tile specimens And the interface fracture of the adhesive was seen. On the other hand, in the cleaning process (ii), both the exterior MS / EP and interior MS are almost cohesive failure of the adhesive, and the adhesive strength is higher than the result of the cleaning process (i), and the better adhesion. Was confirmed. With regard to the sticking M, the interfacial fracture rate was high in the tile test body G of the cleaning process (ii), but both the cleaning process (i) and the cleaning process (ii) were 1 N / mm ^{2 to 2} N / mm ² or more. The adhesive strength was confirmed.

  From the above, it can be seen that the tile cleaning method in which mortar is removed by immersion in hydrochloric acid is more effective in ensuring adhesion than immersing the tile in water for a certain period of time, rather than only washing the tile surface with running water. It was.

(Experiment D-3)
Subsequently, Experiment D-3 was performed in order to confirm whether a difference in the adhesiveness of the tiles was caused by a specific method of washing. In this experiment D-3, in order to remove the salt remaining on the back surface of the tile from which the mortar was removed by acid dipping, washing was performed under various conditions, and the salt remaining on the washed tile was measured and compared. It is.

  FIG. 20 is a table showing cleaning conditions related to Experiment D-3. The test was performed by immersing 50 2-chome (Type I / glazed) tiles in hydrochloric acid and calcium chloride aqueous solution prepared at 1 mol / L for 1 day to simulate the adhesion of residual salt. After immersion, “wet” (wet after removing the solution) The two types of tile test specimens were washed, each of which was left as it was) and “dry” (the state after the solution was taken out and dried as it was). Here, three types of cleaning methods, “water immersion”, “running water cleaning”, and “rubbing cleaning” of the tile specimen were examined. About "water immersion", immersion was performed for 7 days with the amount of water immersion per tile specimen being 100 ml and 300 ml. For “running water washing”, washing with water from the faucet and with a commercially available shower head attached to the faucet, washing in the shower mode, and washing in the high pressure mode were performed. The running time was examined for 2 seconds and 10 seconds. For “rubbing”, the tile specimen was washed by three methods, scrubbing, sponge and hand, and the number of rubbing was examined for 2 times and 5 times for each.

  And about the tile test body after washing | cleaning, the chlorine content in hydrochloric acid and calcium chloride which remain | survives on a tile back surface was measured by performing the fluorescent X-ray analysis of the back surface of a tile, and the washing | cleaning condition was evaluated. FIG. 21 is a graph showing the test result of Experiment D-3 (hydrochloric acid immersion), and FIG. 22 is a graph showing the test result of Experiment D-3 (calcium chloride immersion). Here, as shown in FIG. 21, for the tile specimen immersed in hydrochloric acid, the proportion of chlorine in the elements detected from the back surface of the tile specimen after washing is 1 mass% or less, which depends on the difference in washing method. There was no big difference. On the other hand, as shown in FIG. 22, for the tile specimen immersed in calcium chloride, the ratio of chlorine shown in the elements detected from the back of the tile after washing is the lowest after the water immersion, and the ratio of chlorine is 1 mass% or less. It turned out that it was able to wash effectively. The reason for this is that the salt has penetrated into the tile by immersing the tile in the solution, and it cannot be removed sufficiently only by cleaning the surface, and the salt that has penetrated into the interior by immersing in the water is eluted into the water, It is thought that it can be removed. In addition, since hydrochloric acid has high volatility, it is considered that the salt adhering to the tile volatilized and was not detected regardless of the cleaning conditions.

(Experiment D-4)
Subsequently, Experiment D-4 was conducted in order to examine the conditions under which the salt content penetrating into the tile can be sufficiently removed by water immersion. That is, the above-described Experiment D-2 and Experiment D- are the most effective methods for cleaning a tile from which mortar has been removed by acid immersion, by immersing the treated tile in water and removing residual salts. Therefore, detailed conditions for water immersion were examined.

  Here, since it is considered that the amount of salt permeating into the tile varies depending on the water absorption rate of the tile, four types of tiles (test sample) having different water absorption rates were used as the test samples. FIG. 23 is a list of specimens related to Experiment D-4. As shown in FIG. 23, the specimens have water absorption categories of JIS A-5209 of class I (water absorption of 3.0% or less), class II (water absorption of 10.0% or less), and class III (water absorption). Experiments were performed using tiles with a rate of 50.0% or less. For Type II, two types of tiles were used. The size of each tile specimen was cut to be the same as the surface area of 50 2-chome tiles, and all specimens were made the same size (however, the tile edge surface was not included in the surface area). The test specimens were immersed in an aqueous solution of calcium chloride and hydrochloric acid prepared at 1 mol / L for 28 days, and the tiles taken out after soaking were “wet” (the state in which the solution was left wet) and “dried” (the solution was taken out). Thereafter, the tile test bodies of two levels in a state of being dried as they were were immersed in water. The immersion amount of water was set to 150 ml to 500 ml per tile specimen depending on the test conditions. In addition, the water in which the test specimen is immersed has two conditions of “with replacement” and “without replacement”. With regard to “with replacement”, 24 hours after the test specimen is immersed in water, 7 The water was replaced with new water every day, and “no replacement” was a condition in which the water was not replaced after the test specimen was immersed in water. The test was carried out with the number of test specimens in each specification as one.

  And in order to evaluate the situation where the salt which penetrate | infiltrated the inside of a tile elutes in water after such water immersion start, the measurement of the chlorine ion concentration of the water which has immersed the test body was performed regularly. A chlorine ion detector tube was used to measure the chlorine ion concentration. The chlorine ion concentration was measured after immersing the test specimen in water, 1 minute, 1 hour, 3 hours, 6 hours, 24 hours, and then every 7 days until 28 days. However, the chlorine ion concentration of the test piece with “replacement with water” was measured immediately before the water replacement.

  And about the test body 28 days after water immersion, in order to confirm the residual condition of the salt content on the back surface of a tile test body, material analysis is performed by fluorescent X-ray analysis, and the tile test body before solution immersion and the tile test body after solution immersion Comparison was made with the amount of salt adhering to.

  FIG. 24 is a graph showing the measurement results of chlorine ion concentration related to Experiment D-4 (water immersion after immersion in hydrochloric acid, no replacement of water), and FIG. 25 is the measurement result of chlorine ion concentration related to Experiment D-4 (water after immersion in calcium chloride). FIG. 26 is a graph showing the results of measurement of chloride ion concentration (Experimental D-4 water immersion, with water replacement), and FIG. 27 is related to Experiment D-4. It is a graph which shows a chlorine ion density | concentration measurement result (The water immersion after calcium chloride immersion and the replacement of water are possible).

  As shown in FIGS. 24 to 27, in the tile specimen C having the smallest water absorption rate, the chlorine content eluted by water immersion was low. Further, the tile specimen S having the largest water absorption rate eluted a large amount of chlorine by water immersion, and the result was that the chlorine content almost absorbed by solution immersion was eluted within 7 days after water immersion. Thus, although there is a difference in the period until the chlorine content is completely eluted due to the difference in water absorption rate, regardless of the difference in water absorption rate, by immersing the tile in water for at least 7 days, It can be seen that the slope of the solution becomes smaller and the solution is almost saturated. Therefore, in order to completely elute chlorine ions that have penetrated into the interior of the tile, it is considered preferable to immerse the tile in water for at least 7 days.

  In particular, type I tile specimens having a low water absorption rate hardly absorb chlorine when immersed in a solution, and the amount of eluted chlorine is small. Therefore, it is considered that chlorine ions can be sufficiently eluted by immersion in water for one day. In addition, type III tile specimens with high water absorption absorb a lot of chlorine when immersed in the solution, but the rate of elution when immersed in water is high, so as in the case of class I tile specimens, soak in water for one day. It is considered that chlorine ions can be sufficiently eluted.

  In addition, it is clear from FIG.17 and FIG.19 of experiment D-2 mentioned above that the tile after water immersion has fully ensured adhesiveness. That is, tiles immersed in water (building names A to F) having a water absorption classification of Class I and tiles immersed in water of Class II (building names G and H) have sufficient adhesion as is apparent from FIG. It can be seen that it is secured. In addition, although the water absorption classification is not shown for the tiles with water class III, in view of FIG. 24 to FIG. 27, the class III has eluted chlorine ions as well as the class I and class II. It is considered that the same level of adhesion as Class II and Class II can be secured.

  Further, comparing FIG. 24 to FIG. 27, it became clear that there is almost no influence on the elution rate of the chlorine content due to the presence or absence of water change. However, if the chlorine ion concentration during water immersion is high without replacing water, salt may remain on the surface of the tile after water immersion, so water is replaced during water immersion. It is desirable that the surface be washed with running water after immersion in water.

In addition, as a method for confirming the residual of calcium chloride on the tile back surface, which is a factor for inhibiting tile adhesion, (I) a method for confirming the formation of white precipitate by spraying silver nitrate on the tile back surface (hereinafter referred to as AgNO ₃ spray method). ), (II) A method in which the tile to be checked is immersed in a predetermined volume of water, and the salt concentration of the immersed water is measured using a detector tube for chloride ions (hereinafter referred to as detector tube method), and (III) A method of confirming the residual chlorine content on the back of the tile by XRF analysis may be considered.

Here, it has been found from the examination so far that it is important to sufficiently remove the salt penetrating into the tile in order to ensure the adhesiveness of the tile after removing the mortar by acid immersion. The method that can confirm the removal of the salt penetrating into the inside is the “detector tube method”, and it can be confirmed at a lower cost than other methods.
Furthermore, even if the water absorption rate of the tile is not known, it can be confirmed whether the salt has been removed to an extent suitable for adhesion by immersing in water while measuring the salt concentration as needed by the detector tube method.

(About Experiment E)
Subsequently, Experiment E was performed in order to confirm the presence or absence of residual salt of the acid solution 6 attached to the attached building material 4. In this experiment E, the residue attached to the tile is roughly determined by spraying a silver nitrate aqueous solution onto the tile which is the attached building material 4 and confirming the presence or absence of white precipitate generated based on the reaction between the silver nitrate aqueous solution and calcium chloride. This is an experiment to confirm the presence of salt (calcium chloride).

  Specifically, an aqueous solution of silver nitrate having a concentration of 0.1% was sprayed on the back side of each tile of levels A to F in Experiment D, and the presence or absence of white precipitation was confirmed. As a result, white precipitates can be visually observed on the tiles of levels A to D, and it can be confirmed that residual salts are attached. White tiles cannot be visually observed on the tiles of levels E and F, and the amount of residual salt attached is extremely high. It was confirmed that there was little or no residual salt attached. In this way, it is possible to prevent the adhesion of the residual salt from being inhibited by visualizing the presence or absence of the residual salt and performing the above-described washing process until no white precipitate can be detected.

(Effect of Embodiment 1)
As described above, according to the method for removing a hardened cement body according to the first embodiment, the mortar 3 is removed by an extremely simple method in which the attached building material 4 is arranged in the environment for removing the hardened cement body. It is possible to easily remove the mortar 3 adhering to the adhering building material 4 without the need for manual work, and to reduce the labor, time and cost required for the removal, and the adhering building material. 4 can be reduced.

  Moreover, since at least a part of the mortar 3 is immersed in the acid solution 6, the mortar 3 can be dissolved in the acid solution 6 and removed, and the mortar 3 can be removed very easily.

Moreover, since the adhesion | attachment building material 4 is immersed in the acid solution 6 so that following formula (1) may be satisfy | filled, it becomes possible to dissolve the mortar 3 to such an extent that the mortar 3 can be removed manually.
Σ [i = 1 ton] (M _i L _i / X) [mol / g] ≧ 5.0 × 10 ⁻³ [mol / g] (1)
(here,
i: number of times the acid solution 6 is exchanged or added,
n: total number of times the acid solution 6 is exchanged or added,
M _i : Hydrogen molar concentration [mol / L] of the acid solution 6 in the i-th exchange or addition,
L _i : Volume [L] of the acid solution 6 in the i th exchange or addition,
X: Weight of mortar 3 adhering to adhering building material 4 [g])

Moreover, since the adhesion | attachment building material 4 is immersed in the acid solution 6 so that hydrogen molar concentration M _i of the acid solution 6 in the i-th exchange or addition may satisfy | fill following formula (2), the acid solution 6 which does not correspond to a deleterious substance It is possible to remove the mortar 3 using, and safe and easy removal is possible.
M _i [mol / L] ≦ 100 / M _w [mol / L] (2)
(here,
M _w : molecular weight of the acid substance)

  Further, after the removal step, the surface of the adhered building material 4 is washed and the residual salt of the acid solution 6 adhered to the surface of the adhered building material 4 is removed. Therefore, when the adhered building material 4 is reused on the wall surface, It is possible to prevent the adhesion to the wall surface from being hindered.

  Moreover, since the residual salt of the acid solution 6 adhering to the surface of the adhesion | attachment building material 4 is detected after a removal process, the presence or absence of a residual salt can be confirmed and residual salt can be removed, and when the adhesion | attachment building material 4 is reused for a wall surface Furthermore, it is possible to further prevent the residual salt from inhibiting the adhesion to the wall surface.

(Embodiment 2)
Next, the second embodiment will be described. This Embodiment 2 is a form regarding the method of removing a cement hardening body from the adhesion building material 4 by heating the adhesion building material 4 roughly. In addition, about the structure of the building 1 to which the cement hardening body removal method which concerns on this Embodiment 2 is applied, since it is the same as that of Embodiment 1, detailed description is abbreviate | omitted.

(Cemented body removal method)
Hereinafter, a method for removing a hardened cement body according to the second embodiment will be described.

(Cement hardened body removal method-attached building material acquisition process)
First, the adhesion building material acquisition process which acquires the adhesion building material 4 to which the cement hardening body adhered is performed. In addition, since this adhesion building material acquisition process can be implemented similarly to Embodiment 1, detailed description is abbreviate | omitted.

(Cement cured body removal method-removal process)
Next, the removal process which arrange | positions the adhesion building material 4 in the cement hardening body removal environment which removes the cement hardening body adhering to the adhesion building material 4 from the adhesion building material 4 is implemented. FIG. 28 is a diagram showing the attached building material 4 during the removing step of the method for removing a hardened cement body according to the second embodiment. The “hardened cement body removal environment” is an environment in which the hardened cement body can be removed from the attached building material 4, and in the second embodiment, at least a part of the hardened cement body attached to the attached building material 4 is used. It is a heating environment provided with the heating means which can be heated.

  Thus, although the specific method of heating the adhesion building material 4 is arbitrary, in this Embodiment 2, as shown in FIG. 28, the some adhesion building material 4 is arrange | positioned side by side inside the heating furnace 7, Heat for a predetermined time in the heating furnace 7. The heating furnace 7 is a heating means capable of heating at least a part of the hardened cement body adhering to the adhering building material 4. In addition, although the number of adhesion | attachment building materials 4 is arbitrary, in FIG. 2, what put three adhesion | attachment building materials 4 with respect to one heating furnace 7 is illustrated.

Below, the principle which can remove the mortar 3 from the adhesion | attachment building material 4 by heating is demonstrated. That is, since the mortar 3 is heated to a high temperature and the internal component composition changes and becomes brittle, the mortar 3 is easily peeled off from the attached building material 4. An example of a specific change in the component composition of the mortar 3 is shown below. First, the cement content in the mortar 3 contains Ca (OH) ₂ and CaCO _{3. The} composition of this Ca (OH) ₂ changes depending on the temperature, and expansion and contraction occur. The reaction when the temperature of the heating furnace 7 in this Ca (OH) ₂ is changed from 450 ° C. to 500 ° C. is shown in the following formula (α). The reaction when the temperature of the heating furnace 7 is increased to about 750 ° C. in the CaCO ₃ is represented by the following formula (β).
Ca (OH) ₂ → CaO + H ₂ O (α)
CaCO ₃ → CaO + CO ₂ (β)

As shown in the above formulas (α) and (β), Ca (OH) ₂ in the mortar 3 shrinks as CaO with heating, and CaCO ₃ becomes CaO with heating. It is considered that the mortar 3 is weakened due to the shrinkage, which causes fine cracks in the mortar 3.

  Here, the specific means of heating is arbitrary, and is not limited to the heating furnace 7 as in the second embodiment, and any means can be applied as long as the mortar 3 can be heated. For example, the mortar 3 is not limited to surrounding the mortar 3 as in the heating furnace 7, and the mortar 3 may be heated by a direct fire. Moreover, the direction of the adhesion building material 4 is arbitrary, but more effectively, the adhesion building material 4 is arranged and heated so that the mortar 3 is in contact with the hottest surface (heating surface) in the heating furnace 7. Preferably it is done.

(Example)
Then, the Example of the cement hardening body removal method which concerns on this Embodiment 2 is demonstrated. This example relates to an experiment for specifying optimum conditions for removing a hardened cement in the method of removing a hardened cement.

(About Experiment F)
First, Experiment F was performed in order to confirm the optimal temperature of the heating furnace 7 for removing the mortar 3. In this experiment F, the adhering building material 4 to which the mortar 3 is adhered is accommodated in the heating furnace 7 and heated for 80 minutes, the heated adhering building material 4 is taken out of the heating furnace 7 and hit with a hammer. This is an experiment to measure the number of hits required for removal. In addition, said experiment was done about each when the temperature of the heating furnace 7 is 200 degreeC, 300 degreeC, 500 degreeC, 700 degreeC, 900 degreeC, 1050 degreeC, and 1150 degreeC. FIG. 29 is a diagram illustrating the results of Experiment F. In FIG. Here, when the mortar 3 remaining on the back side surface of the attached building material 4 is removed by blow, the number of blows required for removal is less than the reference number in consideration of work efficiency and the possibility of damage to the attached building material 4 main body. Is preferred. This “reference number” can be arbitrarily determined based on, for example, the strength of the attached building material 4. For example, in the second embodiment, the reference number is assumed to be ten.

Here, referring to FIG. 29, the mortar 3 can be removed by hitting less than the reference number when the heating temperature of the heating furnace 7 is changed from 500 ° C. to 1150 ° C. That is, in order to keep the number of strikes below the reference number (10 times), it is necessary to set the temperature of the heating furnace 7 to 500 ° C. or higher. Therefore, the temperature of the heating furnace 7 is preferably set to 500 ° C. or more. However, if the temperature is too high, the attached building material 4 itself may crack and become brittle, or the attached building material 4 may be discolored. This is not preferable. In particular, if the adhesion building material 4 is heated at a temperature equal to or higher than the firing temperature (for example, 1200 ° C. in the case of tiles), the adhesion building material 4 may be remarkably cracked or discolored. It is preferable to heat. Therefore, based on the above, it is preferable to heat the attached building material 4 so as to satisfy the following formula (3). In addition, it is more preferable if it is the temperature (700 degreeC or more) which can peel by hand, without using a hammer.
500 [° C.] ≦ T ≦ Ts [° C.] (3)
T: Heating temperature [° C]
Ts: Firing temperature of attached building materials [° C.])

(Effect of Embodiment 2)
Thus, according to the method for removing a hardened cement body of the second embodiment, since at least a part of the mortar 3 is heated, the mortar 3 can be weakened by a composition change caused by heating, and the mortar can be very easily performed. 3 can be removed.

Moreover, since the adhesion | attachment building material 4 is heated so that following formula (3) may be satisfy | filled, the mortar 3 can be weakened to the state which can be easily removed by manual work, and the mortar 3 can be removed very easily. At the same time, the temperature can be suppressed to a level that does not affect the attached building material 4, and it is possible to prevent the attached building material 4 from being weakened or discolored by heating.
500 [° C.] ≦ T ≦ Ts [° C.] (3)
(here,
T: Heating temperature [° C]
Ts: Firing temperature of adherent building material 4 [° C.])

[Modifications to Embodiment]
While the first and second embodiments according to the present invention have been described above, the specific configuration and means of the present invention are arbitrarily modified and modified within the scope of the technical idea of each invention described in the claims. It can be improved. Hereinafter, such a modification will be described.

(About problems to be solved and 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 contents, and may vary depending on the implementation environment and details of the configuration of the invention. May be solved, or only some of the effects described above may be achieved. For example, when the hardened cement body that adheres to the attached building material 4 cannot be easily removed by the method of removing the hardened cement body according to the first and second embodiments, the labor, time, and cost required for the removal are reduced. Even if this is not possible, the problem of the present invention is solved when the hardened cement can be removed by a technique different from the conventional technique.

(About dimensions and materials)
The dimensions, shapes, ratios, materials, etc. of the respective parts of the building 1, the mortar 3, and the attached building material 4 described in the detailed description of the invention and the drawings are merely examples, and other arbitrary dimensions, shapes, ratios, materials, etc. It can be.

(Correlation between each embodiment)
The features shown in each embodiment may be interchanged with each other, or one feature may be added to the other. Further, only one of the methods according to each embodiment may be performed, or both may be performed. For example, the mortar 3 is heated as in the second embodiment, and most of the mortar 3 is removed from the attached building material 4 and then the remaining mortar 3 is removed as a finish with the acid solution 6 as in the first embodiment. You may do it. Further, the acid environment and the heating environment may be properly used according to the material of the attached building material 4. For example, when the adhering building material 4 is a material that can be discolored by heating, the mortar 3 is removed with an acid solution 6, and when the adhering building material 4 is a material that can be discolored by an acid, the mortar 3 is removed by heating. Also good. Further, the acid environment and the heating environment may be properly used depending on the thickness and surface area of the mortar 3 attached to the attached building material 4. For example, when the thickness of the mortar 3 is small (for example, less than 10 mm) or the surface area of the mortar 3 is small (for example, less than 10 m ² ), it can be removed with only an acid without heating. The mortar 3 may be removed only with the solution 6.

(Range of acid immersion and heating)
In each embodiment, it was placed in an acid environment or a heating environment including the adhering building material 4, but only the mortar 3 adhering to the adhering building material 4 may be disposed in these environments. In particular, when there is a possibility that the adhering building material 4 is discolored by acid or heating, it is preferable to place only the mortar 3 in an acid environment or a heating environment so that the adhering building material 4 is not immersed or heated in the acid. . Specifically, for example, the attached building material 4 may be placed in an acid environment or a heating environment after being wrapped or protected.

(Appendix)
The method for removing a hardened cement body according to Supplementary Note 1 is a method for removing the hardened cement body from the attached building material to which the hardened cement body has adhered, and removes the hardened cement body from the attached building material. The removal process which arrange | positions the said adhesion | attachment building material under an environment is included.

  The method for removing a hardened cement body according to appendix 2 is the method for removing a hardened cement body according to appendix 1, wherein the environment for removing the hardened cement body is an acid solution capable of immersing at least a part of the hardened cement body adhering to the attached building material. Including an acid environment.

The method for removing a hardened cement body according to appendix 3 is the method for removing a hardened cementitious body according to appendix 2, wherein the attached building material is immersed in the acid solution so as to satisfy the following formula (1) in the acid environment.
Σ [i = 1 ton] (M _i L _i / X) [mol / g] ≧ 5.0 × 10 ⁻³ [mol / g] (1)
(here,
i: number of times the acid solution is exchanged or added,
n: total number of exchange or addition of acid solution,
M _i : hydrogen molar concentration [mol / L] of the acid solution in the i th exchange or addition,
L _i : Volume of acid solution [L] at the i th exchange or addition,
X: Weight of cured cement adhering to adhering building material [g])

The cement hardened body removal method of appendix 4 is the cement cemented body removal method of appendix 3, wherein the hydrogen molar concentration M _i of the acid solution in the i th exchange or addition satisfies the following formula (2).
M _i [mol / L] ≦ 100 / M _w [mol / L] (2)
(here,
M _w : molecular weight of the acid substance)

  The method for removing a hardened cement body according to appendix 5 is the method for removing a hardened cement body according to any one of appendices 2 to 4, wherein after the removing step, the surface of the adhering building material is washed to the surface of the adhering building material. A cleaning step of removing the residual salt of the acid solution adhering thereto;

  The method for removing a hardened cement body according to appendix 6 is the method for removing a hardened cement body according to any one of appendices 2 to 5, wherein the residual salt of the acid solution attached to the surface of the attached building material is removed after the removing step. A detection step of detecting.

  The method for removing a hardened cement body according to appendix 7, in the method for removing a hardened cement body according to any one of appendices 1 to 6, wherein the environment for removing the hardened cement body is at least one of the hardened cement body adhered to the attached building material. A heating environment including heating means capable of heating the part is included.

The method for removing a hardened cement body according to appendix 8 is the method for removing a hardened cementitious body according to appendix 7, wherein the attached building material is heated so as to satisfy the following formula (3) in the heating environment.
500 [° C.] ≦ T ≦ Ts [° C.] (3)
(here,
T: Heating temperature [° C]
Ts: Firing temperature of attached building materials [° C.])

(Additional effects)
According to the method for removing hardened cement according to appendix 1, the hardened cement is removed by an extremely simple method of placing the adhering building material in the environment for removing the hardened cement, and requires manual work by a person having skill. It is possible to easily remove the hardened cement adhering to the adhering building material, and it is possible to reduce the labor, time and cost required for the removal, and possible damage to the adhering building material. It becomes possible to reduce.

  According to the method for removing a hardened cement according to appendix 2, since at least a part of the hardened cement is immersed in an acid solution, the hardened cement can be removed by dissolving it in an acid solution. Can be removed.

According to the method for removing a hardened cement according to Supplementary Note 3, since the adhered building material is immersed in an acid solution so as to satisfy the following formula (1), the hardened cemented body should be able to be removed manually. Can be dissolved.
Σ [i = 1 ton] (M _i L _i / X) [mol / g] ≧ 5.0 × 10 ⁻³ [mol / g] (1)
(here,
i: number of times the acid solution is exchanged or added,
n: total number of exchange or addition of acid solution,
M _i : hydrogen molar concentration [mol / L] of the acid solution in the i th exchange or addition,
L _i : Volume of acid solution [L] at the i th exchange or addition,
X: Weight of cured cement adhering to adhering building material [g])

According to Note 4 hardened cement removal method according hydrogen molar concentration M _i of the acid solution in the i-th replacement or addition, to satisfy the following formula (2), since dipping the attached building material in an acid solution, The hardened cement body can be removed using an acid solution that does not correspond to a deleterious substance, and safe and easy removal is possible.
M _i [mol / L] ≦ 100 / M _w [mol / L] (2)
(here,
M _w : molecular weight of the acid substance)

  According to the method for removing a hardened cement body described in appendix 5, after the removing step, the surface of the attached building material is washed and the residual salt of the acid solution adhering to the surface of the attached building material is removed. It is possible to prevent the residual salt from inhibiting the adhesion to the wall surface when used.

  According to the method for removing a hardened cement body according to appendix 6, since the residual salt of the acid solution adhering to the surface of the attached building material is detected after the removing step, the presence of residual salt can be confirmed and the residual salt can be removed. It becomes possible to further prevent the residual salt from inhibiting the adhesion to the wall surface when the building material is reused on the wall surface.

  According to the method for removing a hardened cement according to appendix 7, since at least a part of the hardened cement is heated, the hardened cement can be weakened by a change in composition due to heating, and the hardened cement can be removed very easily. It becomes possible to do.

According to the method for removing a hardened cement according to appendix 8, since the attached building material is heated so as to satisfy the following formula (3), the hardened cement can be weakened until it can be easily removed manually. It is possible to remove the hardened cement body very easily, and it can be suppressed to a temperature that does not affect the attached building material, and the attached building material becomes weak or discolored by heating. It becomes possible to prevent.
500 [° C.] ≦ T ≦ Ts [° C.] (3)
(here,
T: Heating temperature [° C]
Ts: Firing temperature of attached building materials [° C.])

DESCRIPTION OF SYMBOLS 1 Building 2 Housing 3 Mortar 3a Ground mortar 3b Tension mortar 4 Adhesive building material 4a Groove part 5 Container 6 Acid solution 7 Heating furnace

Claims (8)

A method for removing a hardened cement body, which removes the hardened cement body from an attached building material to which the hardened cement body has adhered,
Under the cement hardened body removal environment that removes the cement hardened body from the attached building material, including a removing step of placing the attached building material,
Cement cured body removal method. The hardened cement body removal environment includes an acid environment including an acid solution capable of immersing at least a part of the hardened cement body attached to the attached building material.
The method for removing a hardened cement body according to claim 1. In the acid environment, the adhering building material is immersed in the acid solution so as to satisfy the following formula (1).
The method for removing a hardened cement body according to claim 2.
Σ [i = 1 ton] (M _i L _i / X) [mol / g] ≧ 5.0 × 10 ⁻³ [mol / g] (1)
(here,
i: number of times the acid solution is exchanged or added,
n: total number of exchange or addition of acid solution,
M _i : hydrogen molar concentration [mol / L] of the acid solution in the i th exchange or addition,
L _i : Volume of acid solution [L] at the i th exchange or addition,
X: Weight of cured cement adhering to adhering building material [g]) The hydrogen molar concentration M _i of the acid solution in the i-th exchange or addition satisfies the following formula (2):
The method for removing a hardened cement body according to claim 3.
M _i [mol / L] ≦ 100 / M _w [mol / L] (2)
(here,
M _w : molecular weight of the acid substance) After the removal step, including a cleaning step of cleaning the surface of the attached building material and removing residual salt of the acid solution attached to the surface of the attached building material.
The method for removing a hardened cement body according to any one of claims 2 to 4. After the removal step, including a detection step of detecting residual salt of the acid solution attached to the surface of the attached building material,
The method for removing a hardened cement body according to any one of claims 2 to 5. The hardened cement body removal environment includes a heating environment including heating means capable of heating at least a part of the hardened cement body attached to the attached building material.
The method for removing a hardened cement body according to any one of claims 1 to 6. In the heating environment, the attached building material is heated so as to satisfy the following formula (3).
The method for removing a hardened cement body according to claim 7.
500 [° C.] ≦ T ≦ Ts [° C.] (3)
(here,
T: Heating temperature [° C]
Ts: Firing temperature of attached building materials [° C.])

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