JP2021031333A - Diagnostic tool for degradation of concrete structure - Google Patents

Abstract

To provide a diagnostic tool for degradation of a concrete structure that is excellent in hardness and production stability and is prevented from being cracked.SOLUTION: This invention relates to a diagnostic tool for degradation of a concrete structure, the concrete structure comprising a tabular mortar panel having: a principal face exposed to the environment in which the concrete structure is placed; and a rear face being a sticking face for the concrete structure or a structure existing in the vicinity thereof. The mortar panel comprises a hardened body of a mortar composition containing a quick-hardening material and cement. The quick-hardening material comprises calcium aluminate and a 1-10C carboxylate salt.SELECTED DRAWING: Figure 1

Description

The present invention relates to a deterioration diagnostic tool for concrete structures.

So far, various developments have been made on deterioration diagnosis technology for concrete structures.
As this kind of technique, for example, the technique described in Patent Document 1 is generally known. Patent Document 1 describes a destructive inspection method for coring and analyzing concrete from a concrete structure.

However, it is necessary to partially destroy the concrete structure by the coring work. In addition, a simpler method is required.
Currently, the development of a non-destructive inspection method is in progress. For example, in Patent Document 2, a concrete structure is installed by attaching a mortar panel to a concrete structure with a liquid epoxy adhesive, peeling it off after a certain period of time, collecting it, and measuring the amount of salt. A method for evaluating the amount of salt in the concrete area has been proposed.

Japanese Unexamined Patent Publication No. 2010-23583 Japanese Unexamined Patent Publication No. 2014-105136

However, as a result of examination by the present inventor, it has been found that the mortar panel described in Patent Document 2 has room for improvement in terms of strength, production stability, and crack prevention.

Generally, the mortar panel is obtained by curing the mortar composition by steam curing.
According to the inventor's knowledge, it has been found that the surface of the mortar panel may be cracked depending on the conditions such as the temperature and humidity of steam curing.

Therefore, as a curing method, we proceeded with the study of a method using a hardened material instead of steam curing.
Calcium aluminate is usually used for cement hardeners.
However, calcium aluminate has shown a result that the pot life is short and the production stability is lowered.
When it was examined to use a carboxylic acid in combination with calcium aluminate, it was possible to extend the pot life relatively, but the rapid hardness was insufficient, and there was a risk that the strength would decrease.
As a result of further studies, by using a salt of carboxylic acid in combination with calcium aluminate instead of carboxylic acid, it is possible to shorten the gel time, that is, to increase the rapid hardness while making the pot life relatively long. found.

Further diligent research based on these findings revealed that by using a salt of a carboxylic acid having 1 or more and 10 or less carbon atoms in combination with calcium aluminate, it is difficult to harden (that is, the pot life is long) just by mixing with water. , We found that it is possible to realize a mortar panel with excellent strength and manufacturing stability and suppressed cracking by using a hardened material that can rapidly harden cement when mixed with cement (highly hardened). The invention was completed.

According to the present invention
A concrete structure composed of a plate-shaped mortar panel having a main surface exposed to the environment in which the concrete structure is placed and a back surface serving as a sticking surface to the structure existing in or near the concrete structure. It is a deterioration diagnosis tool for things
The mortar panel is composed of a cured product of a mortar composition containing a hardener and cement.
The hardened material contains calcium aluminate and a salt of a carboxylic acid having 1 or more and 10 or less carbon atoms.
Deterioration diagnostic tools for concrete structures are provided.

According to the present invention, there is provided a deterioration diagnosis tool for a concrete structure which is excellent in strength and manufacturing stability and in which cracks are suppressed.

(A) is a perspective view schematically showing an example of the deterioration diagnosis tool of the present embodiment, and (b) is a cross-sectional view taken along the line AA of FIG. 1 (a). It is a figure for demonstrating the deterioration diagnosis method of the concrete structure using the deterioration diagnosis tool. (A) is a side view schematically showing a modified example of the deterioration diagnosis tool of the present embodiment, and (b) is a top view of the back surface side of (a). It is a perspective view which shows an example of the formwork used for manufacturing a mortar panel schematically. It is a schematic diagram which shows an example of the package which contains the deterioration diagnosis tool in a packaging bag.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by the same reference numerals, and description thereof will be omitted as appropriate. Further, the figure is a schematic view and does not match the actual dimensional ratio. In this embodiment, the front-back, left-right, up-down directions are defined and described as shown in the figure. However, this is provided for convenience in order to briefly explain the relative relationships of the components. Therefore, it does not limit the direction in which the product according to the present invention is manufactured or used.

The outline of the deterioration diagnosis tool of the concrete structure of this embodiment will be described.

FIG. 1A is a perspective view schematically showing an example of a deterioration diagnosis tool, and FIG. 1B is a cross-sectional view taken along the line AA of FIG. 1A.

The deterioration diagnosis tool 100 of FIG. 1 includes a plate-shaped mortar panel 10 and an adhesion layer 20 provided on the back surface 14 of the mortar panel 10.

The mortar panel 10 has a main surface 12 that is exposed to the environment in which the concrete structure is placed, and a back surface 14 that serves as a sticking surface to the concrete structure or a structure existing in the vicinity thereof.

The adhesion layer 20 is composed of an adhesive surface on which both sides can be adhered, and has a main surface 22 that adheres to the back surface 14 of the mortar panel 10 and a back surface 24 that adheres to the structure.

By using the deterioration diagnosis tool 100 of the present embodiment, the adhesion stability to the concrete structure can be improved and the deterioration of the adherend can be suppressed, so that the deterioration diagnosis of the concrete structure can be stably performed. Further, at the time of deterioration diagnosis, the work of attaching and collecting the deterioration diagnosis tool 100 becomes easy.

FIG. 2 is a diagram for explaining a deterioration diagnosis method of a concrete structure using a deterioration diagnosis tool.

The outline of the deterioration diagnosis method is, for example, to attach and fix the deterioration diagnosis tool 100 to the surface of the concrete structure 200 or the structure 210 of FIG. 2, collect and analyze after a certain measurement period.

Deterioration diagnosis targets concrete structures that are maintained for a long period of time, such as roads, railroads, bridges, civil engineering structures, buildings, port facilities, plants, and electric power facilities. It is possible to evaluate the degree of deterioration of concrete structures exposed to salt-damaged environments such as near the coast, near the bay, and in the ocean.

The place where the deterioration diagnosis tool 100 is installed may be the surface of the concrete structure 200 or the surface of the structure 210 (for example, a soil research type scattered salt collector or the like) existing in the vicinity of the concrete structure 200. The installation surface should be a flat surface without curved surfaces, steps, or uneven parts. On the installation surface, moisture and dirt may be removed by cleaning before the deterioration diagnosis tool 100 is attached.

Explaining the case where the concrete structure 200 is a bridge as a specific installation location, examples of the concrete structure 200 include a bridge girder 202, a pier floor plate 204, a pier wall surface 206, and the like. The deterioration diagnosis tool 100 may be installed on the wall surface of the structure 210 existing in the vicinity of the concrete structure 200. Alternatively, any part of the concrete structure 200 may be installed on the sea side and the mountain side, respectively. The number of installations in the survey target is not particularly limited, but may be a plurality (for example, 3 or more).

The fixed period may be, for example, about one month, but may be about several months to one year.

In the analysis, the chloride ion amount and / or the neutralization depth of the deterioration diagnosis tool 100 after environmental exposure can be measured, and the degree of deterioration of the installed concrete structure 200 can be estimated accurately.

<Deterioration Diagnosis Tool 100>
The mortar panel 10 constituting the deterioration diagnosis tool 100 can be used without any particular limitation if it has a plate shape, but the shape of the back surface 14 when viewed from the vertical direction may be a substantially square shape or a substantially rectangular shape. Good. It is possible to suppress manufacturing variations between lots.

The thickness of the mortar panel 10 is, for example, 3 mm to 20 mm, preferably 4 mm to 15 mm, and more preferably 5 mm to 10 mm. By setting it to the above lower limit value or more, it can be used even for a long measurement period. On the other hand, if it is set to the above upper limit or less, it can be installed even in a narrow place, so that it is possible to evaluate in a state close to the actual environment.

In the present specification, "~" means that an upper limit value and a lower limit value are included unless otherwise specified.

Area of the main surface 12 and the back surface 14 of the mortar panel 10, for ^example, 5 cm 2 100 cm ^2, preferably may be 10 cm ² to 50 cm ^2. By setting it to the above lower limit value or more, the analysis accuracy is improved. In addition, manufacturing stability can be improved. On the other hand, when the value is not more than the above upper limit value, the handleability is improved.

Compressive strength of mortar panel 10, for ^{example, 15N / mm 2 ~30N / mm} 2, is preferably ^{16N / mm 2 ~28N / mm 2} , more preferably at ^{17N / mm 2 ~25N / mm 2} . By setting it to the above lower limit value or more, damage to the mortar panel 10 at the time of recovery can be suppressed. On the other hand, when the value is not more than the above upper limit value, the mortar panel 10 can be easily pulverized during analysis such as measurement of the amount of chloride ions, and the measurement sample can be easily prepared.
The compressive strength of the mortar panel 10 is measured according to JIS A 1108.

The apparent diffusion coefficient of chloride ions in the mortar panel 10 is, for example, 10 cm ² / year or more and 50 cm ² / year or less, preferably 20 cm ² / year or more and 45 cm ² / year or less. This makes it possible to stably evaluate the state of the concrete structure.
The apparent diffusion coefficient of chloride ions in the mortar panel 10 is JSCE-G 572-2018.

The adhesion layer 20 installed on the back surface 14 of the mortar panel 10 may be in the form of a sheet, and may be composed of a double-sided tape having adhesive surfaces on both sides thereof.

The adhesive layer 20 may include an adhesive layer made of an adhesive. The adhesive layer may be provided on at least each of the main surface 22 and the back surface 24, and may be composed of a single layer or a plurality of layers. The adhesion layer 20 may have a base material such as a non-woven fabric or an acrylic foam between the plurality of adhesive layers.

As the pressure-sensitive adhesive, a known pressure-sensitive adhesive material is used. For example, an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, or the like is used. Among these, acrylic adhesives are used from the viewpoint of adhesiveness and durability to concrete structures.

The adhesion layer 20 may be composed of a single mortar panel 10 in the in-plane direction when viewed from a direction perpendicular to the back surface 14, or may be composed of a plurality of sheets.

The shape of the adhesion layer 20 may be a shape that follows the outer shape of the mortar panel 10 when viewed from a direction perpendicular to the back surface 14, and may be, for example, a substantially square shape or a substantially rectangular shape.

The thickness of the adhesion layer 20 is, for example, 0.3 mm to 3.0 mm, preferably 0.4 mm to 2.5 mm, and more preferably 0.5 mm to 2.0 mm. By setting it to the above lower limit value or more, it can be used even for a long measurement period. On the other hand, if it is set to the above upper limit or less, it can be installed even in a narrow place, so that it is possible to evaluate in a state close to the actual environment.

The adhesion layer 20 may cover the entire back surface 14 of the mortar panel 10, or may partially cover the back surface 14. That is, when viewed from a direction perpendicular to the back surface 14 of the mortar panel 10, a portion to which the adhesion layer 20 is not attached may be formed at least in a part of the peripheral region of the back surface 14. Further, there may be a region in which the adhesion layer 20 is not formed all around the peripheral region of the back surface 14.
As a result, when the mortar panel 10 is attached to the concrete structure 200 via the adhesion layer 20, a gap is formed between the concrete structure 200 and the mortar panel 10, so that the mortar panel 10 can be peeled off. It will be easy. Therefore, the workability of the deterioration diagnosis tool 100 can be improved.

When viewed from a direction perpendicular to the back surface 14 of the mortar panel 10, the covering area of the adhesion layer 20 covering the back surface 14 is, for example, 85% to 95%, preferably 85% to 95%, based on the total area of the back surface 14. It is 87% to 93%. By setting it to the above lower limit value or more, it can be used even for a long measurement period. On the other hand, when the value is not more than the above upper limit value, the mortar panel 10 can be easily removed after the measurement period has elapsed.

3A and 3B are schematic views of a modified example of the deterioration diagnosis tool 100, where FIG. 3A is a side view of the deterioration diagnosis tool 100 and FIG. 3B is a top view of the back surface side.

The deterioration diagnosis tool 100 may include a peelable layer 50 on the back surface 24 of the adhesion layer 20.
By peeling the release layer 50 (cover film) from the adhesion layer 20 (double-sided tape) on the back surface 24 side, the deterioration diagnosis tool 100 can be installed. Therefore, the workability of the deterioration diagnosis tool 100 can be improved.
The back surface 24 of the adhesion layer 20 is a surface located on the opposite side of the main surface 22 which is in close contact with the back surface of the mortar panel 10. Further, by protecting the adhesive surface of the adhesive layer 20 with the release layer 50, it is possible to prevent the adhesive surface (back surface 24) from being contaminated before use.

The release layer 50 is made of a known material, but may be made of, for example, silicone-treated flat paper (release paper), polyester, or the like.

Further, in the deterioration diagnosis tool 100, it is sufficient that the main surface 12 of the deterioration diagnosis tool 100, which is an exposed surface, is exposed, and even if the shielding layer 30 is provided on another surface, for example, the side surface 16 of the deterioration diagnosis tool 100. Good.
For example, all four side surfaces 16 of the mortar panel 10 having a substantially square or rectangular shape may be covered with the shielding layer 30.

The shielding layer 30 may be any one that shields chloride ions or carbon dioxide, and a metal sealing tape in which an adhesive layer is laminated on the metal layer, for example, aluminum tape may be used. The entire side surface 16 may be covered with aluminum tape. As a result, the deterioration diagnosis tool 100 capable of stable evaluation can be realized by setting the environmental exposure surface as one surface (main surface 12).

As shown in FIG. 3A, a label 40 may be formed on the shielding layer 30. The label 40 may be printed or written, or may be engraved. The engraved label 40 is excellent in recognizability even after a long measurement period. For example, a stamped aluminum tape can be used for the shielding layer 30.

The label 40 may indicate various information such as a lot number and a date of manufacture. Alternatively, it may include initial information such as the mass of the initial mortar panel 10 before installation. As a result, the deterioration diagnosis tool 100 having excellent traceability is obtained.

The mortar panel 10 may be composed of a cured product of a mortar composition containing cement and a hardened material.

Hereinafter, the raw materials and additives of the mortar composition will be described.
The mortar composition according to the present embodiment contains hard materials, cement, fine aggregates, and water as raw materials.

The hardened material of the present embodiment contains calcium aluminate and a salt of a carboxylic acid having 1 or more and 10 or less carbon atoms.
By using a salt of a carboxylic acid having 1 to 10 carbon atoms in combination with calcium aluminate, it is difficult to harden by simply mixing it with water (that is, it has a long pot life), but when it is mixed with cement, the cement suddenly becomes hard. It is possible to produce a hardened material that can be hardened (highly hardened). Therefore, the production stability and strength of the mortar composition can be improved.

(Calcium aluminumate)
_{Calcium aluminate is a general term for substances having hydration activity, which contain aluminum oxide (Al 2} O ₃ ) and calcium oxide (CaO) as main components in the technical field of hydraulic materials. Here, the "main component" means that the total content of aluminum oxide and calcium oxide in the entire calcium aluminate is, for example, 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. means.

As the calcium aluminate, either crystalline or amorphous can be used. From the viewpoint of further enhancing the rapid hardness, an amorphous substance, for example, an amorphous calcium aluminate produced by quenching after melting is preferable.

CaO / _Al 2 _{O 3} molar ratio in the calcium aluminate is preferably 1.0 to 3.0, more preferably 1.7 to 2.5. By appropriately adjusting this molar ratio, the rapid hardness can be further increased, and the initial strength of the obtained cement composition can be further increased.

The content of impurities ( _{components other than CaO and Al 2} O ₃ ) in the calcium aluminate is preferably 15% by mass or less, more preferably 10% by mass or less. When the impurities are 15% by mass or less, the rapid hardness can be further enhanced, and the initial strength of the obtained cement composition can be further enhanced.
Here, typical examples of impurities include silicon oxide, magnesium oxide, and sulfur oxide. Other organic, alkali metal oxides, alkaline earth metal oxides, titanium oxide, iron oxide, alkali metal halides, alkaline earth metal halides, alkali metal sulfates, some of these are CaO, Al ₂ O _3, or the Examples of impurities include those substituted or solid-dissolved in. Of course, impurities are not limited to these.

The vitrification rate of calcium aluminate is preferably 70% or more, more preferably 90% or more in terms of reaction activity. By making this value appropriate, the initial strength of the obtained cement composition can be further increased.
The vitrification rate is determined by measuring the main peak area S of crystalline minerals in advance by powder X-ray diffraction method for the measurement sample, then heating at 1000 ° C. for 2 hours, and then slowly cooling at a cooling rate of (1 to 10 ° C.) / min. _{Then, the main peak area S 0} of the crystalline mineral after heating by the powder X-ray diffraction method is obtained, and the vitrification rate χ is calculated by using the values of _{these S 0 and S and using the following formula.}
Vitrification rate χ (%) = 100 × (1-S / S ₀ )

The particle size of the calcium aluminate, in terms of initial strength development is preferably more than Blaine specific surface area ^{3000cm 2 / g, 5000cm 2 /} g or more is more preferable. The upper limit is, for example, 9000 cm ² / g or less. By increasing this value moderately, the rapid hardness can be further increased, and the initial strength of the obtained cement composition can be further increased. Further, by appropriately reducing this value, the pot life can be further extended.

Alumina cement can be mentioned as a specific example of calcium aluminate. That is, commercially available alumina cement or the like may be used as a calcium aluminate raw material for producing a hardened material.
Specific examples of alumina cement include alumina cement No. 1 and alumina cement No. 2. These can be purchased from Denka Co., Ltd. and AGC Co., Ltd.

In the hardened material of the present embodiment, only one type of calcium aluminate may be used, or two or more types of calcium aluminate having different properties / physical properties may be used in combination.

(Salt of carboxylic acid having 1 or more and 10 or less carbon atoms)
In the present specification, the salt of a carboxylic acid having 1 or more and 10 or less carbon atoms means a compound in which the proton of the carboxy group of the carboxylic acid having 1 or more and 10 or less carbon atoms is substituted with a cation. In other words, a salt of a carboxylic acid having 1 or more and 10 or less carbon atoms is obtained by preparing a carboxylic acid having 1 or more and 10 or less carbon atoms as a starting material and reacting (neutralizing reaction) with an appropriate basic substance or the like. Is something that can be done.
The number of carbon atoms is more preferably 1 or more and 8 or less, still more preferably 1 or more and 5 or less, particularly preferably 1 or more and 3 or less, and particularly preferably 1 or 2.

The carboxylic acid having 1 or more and 10 or less carbon atoms may be a monocarboxylic acid or a polycarboxylic acid (for example, a dicarboxylic acid or a tricarboxylic acid). From the viewpoint of cost and the like, a monocarboxylic acid is preferable.

The "carboxylic acid having 1 or more and 10 or less carbon atoms" in the salt of a carboxylic acid having 1 or more and 10 carbon atoms includes formic acid, acetic acid, propionic acid, butyric acid, valeric acid, oxalic acid, succinic acid, adipic acid, and hydroxycarboxylic acid. (Carboxylic acid having a hydroxy group) and the like can be mentioned. Of these, formic acid or acetic acid is preferable from the viewpoint of availability, cost, effect, and the like.
It is preferable that the carboxylic acid having 1 or more and 10 or less carbon atoms is not a hydroxycarboxylic acid from the viewpoint of particularly increasing the fast-hardening property and particularly extending the pot life of the quick-hardening agent.

The carboxylic acid salt is preferably a metal salt of a carboxylic acid. Specifically, the carboxylic acid salt can be a lithium salt, a sodium salt, a potassium salt, a magnesium salt, a calcium salt, a barium salt, or the like of a carboxylic acid. Among these, the carboxylate is preferably a calcium salt of a carboxylic acid.

As another viewpoint, the carboxylic acid salt is preferably a salt of a carboxylic acid having a relatively small number of carbon atoms, as described above. More specifically, the carboxylic acid salt is preferably a salt of formic acid or a salt of acetic acid, more preferably a metal salt of formic acid or a metal salt of acetic acid.
According to the findings of the present inventors, a salt of a carboxylic acid having a relatively small number of carbon atoms such as formic acid and acetic acid can be used as a hardener as compared with a known salt of a carboxylic acid having a large number of carbon atoms (more than 10 carbon atoms). It tends to be used for a long time and has excellent rapid hardness when mixed with cement.

The most preferred carboxylate is calcium acetate or calcium formate.

The amount of the carboxylate may be appropriately adjusted in consideration of the desired balance such as pot life and rapid hardness.
From the viewpoint of the balance between the length of pot life before mixing with cement and the rapid hardness after mixing with cement, the amount of carboxylate is preferably 0. It is 1 part by mass or more and 50 parts by mass or less, more preferably 0.1 part by mass or more and 25 parts by mass or less, and further preferably 0.15 parts by mass or more and 10 parts by mass or less.
The hardened material of the present embodiment may contain only one type of carboxylate or two or more types. In the latter case, it is preferable that the total amount of the two or more kinds of carboxylates is within the above numerical range.

(plaster)
The hardened material of the present embodiment may preferably further contain gypsum. The inclusion of gypsum facilitates the design of longer pot life before mixing with cement.

The plaster that can be used is not particularly limited. In addition, the combined use of different types of gypsum is not excluded.
Examples of gypsum include hemihydrate gypsum and anhydrous gypsum. Anhydrous gypsum is preferable in terms of strength development. More specific examples of anhydrous gypsum include phosphoric acid by-product anhydrous gypsum and natural anhydrous gypsum.
As for the pH when the gypsum is immersed in water, a weak alkaline to acidic pH of 8 or less is preferable. When this pH is appropriately low, the solubility of the gypsum component can be lowered, and the initial strength development can be further enhanced. The pH here is the pH of a diluted slurry of gypsum / ion-exchanged water = 1 g / 100 g at 20 ° C. measured by an ion-exchange electrode or the like. The pH is more preferably 3 or more and 8 or less, and further preferably 5 or more and 7 or less.

The particle size of the gypsum, and the initial strength development, in terms of longer pot life, preferably 3000 cm ² / g or more in Blaine specific surface area value, 5000 cm ² / g or more is more preferable. From the viewpoint of longer pot life, this value is preferably from 30000cm ² / g, more preferably at most 20000 cm ² / g.

The amount of gypsum is preferably 50 parts by mass or more and 250 parts by mass or less, and more preferably 70 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of calcium aluminate.
By setting the amount of gypsum to 50 parts by mass or more, a longer pot life can be obtained. Further, by setting the amount of gypsum to 250 parts by mass or less, the initial strength of the cured product (concrete) obtained by mixing the hardener and cement can be increased.

(Other ingredients)
The hardened material of the present embodiment may contain any component other than the above as long as the desired effect is not significantly impaired.
As an example, the hardened material of the present embodiment does not correspond to a relatively small amount of an organic acid or a salt thereof (a salt of a carboxylic acid having 1 or more and 10 or less carbon atoms) for the purpose of fine-tuning the pot life and the quick-hardening property. Things), carbonates, heavy metal carbonates, calcium hydroxide, alkali hydroxides, sulfates, sulfites, etc. may be included. Of course, the hardened material of the present embodiment does not have to contain these components.

The hardened material of the present embodiment usually does not contain a hydraulic cement component other than calcium aluminate (other than alumina cement) such as Portland cement.

In the hardened material of the present embodiment, usually, (1) first, a coagulation adjusting agent (optional) and a hardened material are added to water to prepare a first liquid, and (2) the first liquid. May be used in the procedure of mixing with water-kneaded cement (second liquid).

As the cement, known ordinary cement, blast furnace cement and the like can be used.

As the fine aggregate, siliceous fine aggregate (silk sand, standard sand for cement strength, etc.), alumina fine aggregate, etc. can be used. Silica-based aggregates and alumina-based aggregates hardly react with cement and chloride ions. Therefore, the stability of deterioration diagnosis using the mortar panel can be improved.

The fine aggregate may be configured not to contain a limestone-based aggregate. When a limestone-based aggregate is used, calcium aluminate monocarbonate hydrate and calcium aluminate hemicarbonate hydrate are produced, which may reduce the stability of deterioration diagnosis using a mortar panel.

The water is not particularly limited, but tap water or the like may be used.

The water / cement ratio (W / C ratio) may be adjusted appropriately, but may be, for example, 30% to 70%. By setting it to the above lower limit value or more, the density of the mortar panel becomes appropriate, and by setting it to the above upper limit value or less, excessive porosity can be suppressed.

The ratio of cement to fine aggregate may be, for example, 1: 0.5 to 1: 4 in terms of mass ratio. By setting the ratio of the fine aggregate to 0.5 or more, it is possible to manufacture a uniform mortar panel. In addition, the fineness of the mortar panel can be adjusted appropriately. On the other hand, by setting the ratio of the fine aggregate to 4 or less, a uniform mortar panel can be manufactured, and deterioration diagnosis stability using the mortar panel can be improved.

The mortar composition may contain additives such as a water reducing agent, a thickener, and an antifoaming agent, if necessary. These may be used alone or in combination of two or more. Further, other additives such as a dispersant, a curing accelerator, and a retarding agent may be contained as long as the object of the present invention is not impaired.

The water reducing agent is not particularly limited, but a polyalkylallyl sulfonate-based water reducing agent, an aromatic aminosulfonate-based water reducing agent, a melamine formalin resin sulfonate-based water reducing agent, and the like can be used.
Examples of the polyalkylallyl sulfonate-based water reducing agent include salts of methylnaphthalene sulfonic acid formalin condensate, naphthalene sulfonic acid formalin condensate, anthracene sulfonic acid formalin condensate and the like.
In addition, general water reducing agents such as lignin sulfonate-based water reducing agent, polyol-based water reducing agent, and oxycarboxylic acid salt-based water reducing agent may be used. These may be used alone or in combination of two or more.

The water reducing agent may be contained, for example, 0.05 parts by mass to 2.0 parts by mass with respect to 100 parts by mass of cement. By adding the water reducing agent, it is possible to prevent the mortar from deteriorating and forming a porous structure with large variations.

The thickener is not particularly limited, and examples thereof include methyl cellulose type, polyethylene glycol and ethylene oxide type, acrylic type such as polyacrylic amide, and polyvinyl alcohol type, and are already commercially available as an inseparable admixture in water. You can use what you have. The thickener may be contained, for example, 0.05 parts by mass to 2.0 parts by mass with respect to 100 parts by mass of cement.

The defoaming agent is not particularly limited, but is an oxyalkylene defoaming agent (polyether defoaming agent), a silicone defoaming agent, an alcohol defoaming agent, a mineral oil defoaming agent, a fatty acid defoaming agent, and a fatty acid. Ester-based defoamers and the like can be used. The defoaming agent may be contained, for example, 0.05 parts by mass to 2.0 parts by mass with respect to 100 parts by mass of cement.

By appropriately controlling the blending ratio of the water reducing agent, the thickener and the defoaming agent, it becomes possible to realize a mortar panel in which the variation of the porous structure is suppressed.

By adjusting the raw materials (cement, water, fine aggregate), additives, and W / C ratio, a mortar panel with a higher chloride ion diffusion coefficient than concrete can be realized. This makes it possible to efficiently take in flying salt, and enables analysis and deterioration diagnosis in a short period of time.

The mortar composition can be obtained by a method of mixing the above-mentioned materials (raw materials and additives). The mixing method is not particularly limited, but each material may be mixed at the time of construction, or a part or all of them may be mixed in advance. A mixing device may be used for kneading the materials. Set the rotation speed, kneading time, and material charging order at the time of kneading as appropriate.

As the mixing device, a known device can be used, and examples thereof include a tilting mixer, an omni mixer, a proshare mixer, a Henschel mixer, a V-type mixer, and a Nauter mixer.

<Manufacturing method of mortar panel>
The mortar panel 10 according to the present embodiment can be obtained by curing the above mortar composition.
The method for producing the mortar panel is not particularly limited, and may include, for example, a step of pouring the mortar composition into the mold and a step of curing the mortar composition.

FIG. 4 is a perspective view schematically showing an example of a mold 60 used for manufacturing a mortar panel.

The mold 60 of FIG. 4 is a mold for molding a mortar panel, and the molding space 66 in the mold 60 is filled with a mortar composition to form a mortar panel 10 having a main surface 12, a back surface 14, and a side surface 16. Can be molded. The molding space 66 may have a structure that matches the three-dimensional shape of the mortar panel 10, and may be formed of, for example, a substantially square or a substantially rectangular parallelepiped.

The molding space 66 of the mold 60 may be composed of the volume of one mortar panel, or may be composed of the volume of a plurality of mortar panels. The molding space 66 may be partitioned by a plurality of partition plates 64. The partitioned individual molding spaces 66 are composed of the volume of one mortar panel.

The mold 60 may be made of a metal material, and a steel material may be used as the metal material from the viewpoint of durability and manufacturing stability during repeated use.

The formwork 60 may be composed of one or more metal members. A plurality of metal members are fixed by a fixing jig to form a formwork 60. Since the mold can be removed by removing the fixing jig, the mold can be easily removed.

The partition plate 64 may be fixed to the mold 60, may be provided integrally with the mold 60, or may be a removable movable plate. By forming the formwork 60 with a movable plate, it becomes easy to remove the mold.

The mortar composition is poured using the above mold 60. The mortar composition is poured from the upper surface opening of the mold 60 which does not have a frame corresponding to one surface of the side surface 16 of the mortar panel 10 to fill the molding space 66. Anything protruding from the top opening may be removed using an instrument such as a squeegee. Further, the mortar composition at the upper surface opening portion may be smoothed.

The mold 60 may be vibrated using a vibrating device. The mold 60 may be vibrated at the time of pouring the mortar composition or after pouring. As a result, variation between lots can be suppressed.

Next, the mortar composition can be cured by allowing the mold 60 filled with the mortar composition to stand at room temperature for a predetermined time. As the curing conditions, for example, the mixture may be allowed to stand at 15 ° C. to 25 ° C. and a relative humidity of 70% to 85% for 3 hours to 5 hours.

After that, the mold 60 is demolded to obtain one or a plurality of mortar panels 10.

A plurality of mortar panels 10 may be obtained by cutting from one mortar bar with a diamond cutter. From the viewpoint of suppressing the variation between lots in the mortar panel 10, a method of forming a plurality of mortar panels 10 from one mold 60 using a partition plate 64 is preferable.

The adhesion layer 20 is attached to the obtained mortar panel 10 to obtain a deterioration diagnosis tool 100.
The deterioration diagnosis tool 100 may be stored in a packaging bag. A plurality of mortar panels 10 having less variation in various characteristics may be selected and stored in the same packaging bag.

FIG. 5 shows a schematic view of a package 300 in which the deterioration diagnosis tool 100 is housed in the packaging bag 310.

The package 300 of FIG. 5 includes one or more deterioration diagnosis tools 100 and a packaging bag 310 for accommodating the deterioration diagnosis tool 100.

The packaging bag 310 may contain, for example, three deterioration diagnostic tools 100. The plurality of deterioration diagnosis tools 100 may be housed in a laminated state in the packaging bag 310. A release layer 50 provided on the back surface 24 of the adhesion layer 20 between the mortar panels 10 can exert the function of a cushioning material. By laminating, it is possible to prevent the mortar panels 10 from coming into contact with each other and being damaged.

The packaging bag 310 may be an aluminum pouch made of an aluminum laminated film. The aluminum laminated film may be a laminated film in which an aluminum layer and a resin layer are laminated. In addition to aluminum and resin, the packaging bag 310 may contain other materials for the purpose of enhancing the gas barrier property and lowering the water vapor permeability.

The thickness of the packaging bag 310 is not particularly limited, but is 50 μm or more and 300 μm or less, more preferably 80 μm or more and 250 μm or less, and further preferably 100 μm or more and 200 μm or less. By setting the value to the above lower limit or more, the mechanical strength and gas barrier property of the packaging bag 310 can be improved. By setting the value to the upper limit or less, the handleability of the packaging bag 310 is improved.

As the form of the packaging bag 310, for example, a standing pouch, a two-way sticker, a three-way sticker, a four-way sticker, or the like is used.

The inside of the packaging bag 310 may be degassed or maintained in an inert gas atmosphere.

The packaging bag 310 may be provided with a chuck 320 that can be opened and closed. The deterioration diagnosis tool 100 taken out from the packaging bag 310 can be housed in the packaging bag 310 again after the measurement period has elapsed.

Further, the packaging bag 310 with the chuck 320 may be provided with a writable sticker (label) on the surface. As a result, the deterioration diagnosis tool 100 can be easily identified even at the time of collection.

The package 300 is packed in a box such as a cardboard box or a plastic case. That is, the packing box includes a plurality of packages 300 and a box for accommodating the packages 300. Thereby, the transport efficiency of the package 300 can be improved.

In the packing box, at least a part around the package 300 may be covered with a cushioning material. As the cushioning material, a known cushioning material such as a bubble wrap sheet or paper can be used.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than the above can be adopted. Further, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the description of these Examples.

<Preparation of hard material>
Based on the raw material ratios in Table 1 below, salts of calcium aluminate, gypsum and carboxylic acid are mixed using a Prosheer mixer (WB type, manufactured by Pacific Machinery & Engineering Co., Ltd.) to obtain hardened materials A to E. It was.

Each of the obtained hard materials A to E, 0.375 g of a coagulation adjuster (Denka Setter D-100, manufactured by Denka Co., Ltd.) and 474 g of water were sufficiently kneaded to prepare the first liquids A to E. ..

<Preparation of mortar composition>
(Test Example 1)
The obtained first liquid A 3 g, cement (Denka, ordinary cement) 628.0 g, water reducing agent (Daiichi Kogyo Seiyaku Co., Ltd., Cellflow 110P, polyalkylallyl sulfonate-based water reducing agent) 2.4 g, increased. 3.4 g of a thickener (MH4000P2 manufactured by Shin-Etsu Chemical Industry Co., Ltd., methylcellulose-based thickener) and 3.4 g of a defoaming agent (SN Deformer 14HP manufactured by San Nopco Co., Ltd., polyether-based defoaming agent) were weighed and mixed.
To these mixtures, add 1350.0 g of standard sand ((one company) Cement Association, standard sand for cement strength test) and 376.8 g of water (tap water) (water / cement ratio: 60%), and use a mixer. The mixture was kneaded to obtain a mortar composition A.

(Test Examples 2-5)
Mortar compositions B to E were obtained in the same manner as in the mortar composition A except that the first liquids B to E were used instead of the first liquid A.

(Test Example 6)
Cement (Denka, ordinary cement) 628.0 g, thickener (Shin-Etsu Chemical, MH4000P2, methylcellulose thickener) 3.4 g, defoamer (Sannopco, SN deformer 14HP, polyether) 3.4 g of antifoaming agent) was weighed and mixed. To these mixtures, add 1350.0 g of standard sand ((one company) Cement Association, standard sand for cement strength test) and 376.8 g of water (tap water) (water / cement ratio: 60%), and use a mixer. The mixture was kneaded to obtain a mortar composition F.

<Making a mortar panel>
(Example 1)
A mold 60 of FIG. 4 having a plurality of molding spaces 66 partitioned by a movable partition plate 64 is prepared.
Using a table vibrator, the mortar composition A immediately after preparation was poured into each of the molding spaces 66 of the mold 60 while vibrating the mold 60 under the following conditions.
Vibration condition of table vibrator:
・ Time: 6 minutes ・ Vibration motor rotation speed: 2800 ± 50 rpm
・ Shaking table: Total amplitude 0.8 ± 0.05mm

After the pouring, the mold 60 was allowed to stand in a room at 25 ° C. and a relative humidity of 80% for 3 hours starting immediately after the preparation of the mortar composition A.
After standing, the fixing jig of the mold 60 was removed, and the mold 60 was removed to obtain a plate-shaped mortar panel A.
The mortar panel A had a substantially rectangular shape having a thickness of about 5 mm × a length of about 4 cm × a width of about 4 cm.

(Examples 2 and 3)
Plate-shaped mortar panels B and C were obtained in the same manner as in Example 1 except that the mortar compositions B and C were used instead of the mortar composition A.

(Comparative Examples 1 and 2)
Plate-shaped mortar panels D and E were obtained in the same manner as in Example 1 except that the mortar compositions D and E were used instead of the mortar composition A.

(Comparative Example 3)
A plate-shaped mortar panel F was formed in the same manner as in Example 1 except that the mortar composition F was used instead of the mortar composition A and the following steam curing was performed instead of allowing the mortar composition F to stand indoors. Obtained.

The mold was allowed to stand in a constant temperature and humidity chamber at 20 ° C. and a relative humidity of 80%, and steam curing was performed under the following conditions.
Conditions for steam curing:
-Hold at 20 ° C for 4 hours.
-The temperature is raised from 20 ° C. to 80 ° C. over 1 hour.
-Hold at 80 ° C. for 8 hours.
・ By natural cooling, the temperature drops to 20 ° C.

The obtained mortar panel was evaluated for the following evaluation items. The results are shown in Table 2.
In Table 2, "-" indicates that the evaluation was not performed.

(Strength)
The mortar composition was poured into the mold 60, and the strength at the stage where the curing had not yet sufficiently progressed was measured by touch. Then, it was evaluated in the following three stages.
⊚: The shape did not change even when the mold was removed, and the cement composition did not dent even when pressed with a finger.
◯: The shape did not change even when the mold was removed, but it was slightly dented when the cement composition was pressed with a finger. Alternatively, the shape did not change even when the mold was removed, but it was in a dented state when the cement composition was pressed with a finger.
X: The shape was lost when the mold was removed.

It was found that the mortar panels of Examples 1 to 3 showed superior results in initial hardness as compared with Comparative Example 2. It is presumed that when the hardened material E of Comparative Example 2 is used, the gel time (the time from mixing the hardened material with cement until the mixture loses fluidity) becomes relatively long.

(Manufacturing stability)
A predetermined amount of mortar composition was sequentially poured into three molds 60. The mortar panels obtained from the first and last molds 60 were evaluated for variations in density and mass.
The case where the variation in density and mass of the mortar panel was suppressed and there was no problem in practical use was evaluated as ◯, and the case where the variation in density and mass of the mortar panel was large and could not be used in practical use was evaluated as x.

It was found that the mortar panels of Examples 1 to 3 showed excellent production stability as compared with Comparative Example 1. Further, since the mortar composition D used in Comparative Example 1 was cured in a relatively short time, the filling workability in the mold was lower than that in Examples 1 to 3.
When the hardened material D of Comparative Example 1 is used, the liquid prepared by mixing the hardened material with water or a coagulation regulator is allowed to stand, and the pot life until the formation of solid content (coarse particles) is observed. It is presumed that it will be relatively short.

(Surface condition of mortar panel: crack / discoloration)
The surface appearance of the obtained mortar panel was visually observed to confirm the condition.
In the mortar panel, the case where no crack or discoloration occurred was evaluated as ◯, and the case where at least one of the crack or discoloration occurred was evaluated as x.

It was found that the mortar panels of Examples 1 to 3 showed results in which cracks and discoloration were suppressed on the surface as compared with Comparative Example 3. In the case of the steam curing of Comparative Example 3, it is presumed that the surface may be discolored by the steam generated by the boiler or the like, and that the surface may be cracked depending on the humidity and temperature conditions of the steam.
Further, the mortar panels of Examples 1 to 3 could be cured in a shorter time than that of Comparative Example 3.

<Making a deterioration diagnosis tool>
Deterioration diagnosis tools were prepared using the mortar panels A to C of Examples 1 to 3.
First, an acrylic adhesive double-sided tape (manufactured by 3M, 4485, tape thickness: 0.5 mm, with release paper on one side) was cut into a length of 3.8 cm and a width of 3.8 cm. The adhesive surface of the cut tape was attached to the back surface of the mortar panel as shown in FIG. 1 (a).
Subsequently, the adhesive surfaces of the aluminum seal were attached to all four side surfaces of the mortar panel as shown in FIG. 3 (b). From the above, deterioration diagnosis tools A to C were obtained.

The release paper was peeled off from the obtained double-sided tapes of the deterioration diagnosis tools A to C, and the adhesive surface was adhered to the flat surface of the outdoor concrete structure. To analyze the total amount of chloride ions contained in each mortar panel by exposing the deterioration diagnostic tools A to C for several months (1 month or more and less than 1 year), and then collecting and analyzing them. Was made. In addition, it was found that cracking of the mortar panel was suppressed from the time of installation to the time of recovery, and the installation durability was excellent.
Therefore, by using the deterioration diagnosis tool of the example, it is possible to stably estimate the condition of the concrete in the vicinity where the deterioration diagnosis tool is fixed.

10 Mortar panel 12 Main surface 14 Back surface 16 Side surface 20 Adhesive layer 22 Main surface 24 Back surface 30 Shielding layer 40 Label 50 Peeling layer 60 Formwork 64 Partition plate 66 Molding space 100 Deterioration diagnosis tool 200 Concrete structure 202 girder 204 Pier floor plate 210 Structure Body 300 Package 310 Packaging bag 320 Chuck

Claims (9)

A concrete structure composed of a plate-shaped mortar panel having a main surface exposed to the environment in which the concrete structure is placed and a back surface serving as a sticking surface to the structure existing in or near the concrete structure. It is a deterioration diagnosis tool for things
The mortar panel is composed of a cured product of a mortar composition containing a hardener and cement.
The hardened material contains calcium aluminate and a salt of a carboxylic acid having 1 or more and 10 or less carbon atoms.
Deterioration diagnostic tool for concrete structures. The deterioration diagnosis tool for a concrete structure according to claim 1.
In the hardened material, the salt of the carboxylic acid contains a metal salt of the carboxylic acid.
Deterioration diagnostic tool for concrete structures. The deterioration diagnosis tool for a concrete structure according to claim 1 or 2.
The fastest hardwood, CaO / _Al 2 _{O 3} molar ratio in said calcium aluminate is 1.0 to 3.0, degradation diagnostic tools of the concrete structure. The deterioration diagnosis tool for a concrete structure according to any one of claims 1 to 3.
A tool for diagnosing deterioration of concrete structures in which the hardened material contains gypsum. The deterioration diagnosis tool for a concrete structure according to any one of claims 1 to 4.
A tool for diagnosing deterioration of a concrete structure in which the amount of the salt of the carboxylic acid in the hardened material is 0.1 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the calcium aluminate. The deterioration diagnosis tool for a concrete structure according to any one of claims 1 to 5.
A deterioration diagnosis tool for a concrete structure provided with an adhesion layer on the back surface of the mortar panel. The deterioration diagnosis tool for a concrete structure according to any one of claims 1 to 6.
Is measured according to JIS A 1108, the compressive strength of the mortar panel is 15N / mm ² or more 30 N / mm ² or less, the deterioration diagnostic tools of the concrete structure. The deterioration diagnosis tool for a concrete structure according to any one of claims 1 to 7.
A deterioration diagnosis tool for concrete structures in which the thickness of the mortar panel is 3 mm or more and 20 mm or less. The deterioration diagnosis tool for a concrete structure according to any one of claims 1 to 8.
A shielding layer that shields chloride ions or carbon dioxide is provided on the side surface of the mortar panel.
Deterioration diagnostic tool for concrete structures.

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