JP2007216667A - Paint for retarding cement setting, method for treating concrete surface, and method for manufacturing concrete structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inorganic paint for retarding cement setting which is capable of easily forming an environmentally excellent coated film despite of any shapes, the film having both of excellent adhesivity hard to break or transfer by casting concrete and cement setting retardation properties, and a method for treating a concrete surface comprising using the same and a method for manufacturing a concrete structure. <P>SOLUTION: The inorganic paint capable of forming a coated film having cement setting retardation properties comprises a cement setting retarder, an aqueous solution of an alkali silicate such as sodium silicate and/or potassium silicate imparting adhesivity and capability of forming a coated film, filler and water, and optionally a thickener for retaining filler dispersibility. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention relates to an inorganic paint for delaying cementation, which can be used when placing concrete, and can efficiently expose the aggregate to a predetermined portion of the obtained concrete surface by washing with water. The present invention relates to a processing method and a method for manufacturing a concrete structure using the processing method.

The method of exposing a part of the aggregate to the surface of the hardened concrete is used for forming the appearance of the concrete, preventing the slippage of the concrete road surface, and strengthening the adhesion of the concrete joint surface.
As a treating agent used in such a method, for example, Patent Documents 1 to 5 propose surface treating agents containing a cement setting retarder and a thickener. The surface treatment agent is applied to a concrete casting mold, and after the concrete is removed from the mold, the concrete surface is washed with water to expose the aggregate.
However, since these surface treatment agents have low adhesive strength with the formwork, it is difficult for the surface treatment agent to flow together with the concrete during the concrete pouring and to keep the treatment agent on the portion to be surface treated. Not only can the surface treatment of the portion not be performed, but also a problem that a part of the treatment agent flows in a portion where it is not necessary to perform such a surface treatment and color unevenness and spots occur on the concrete surface.
Therefore, in Patent Documents 6 to 12, a cement setting delay that can prevent a setting delay component from flowing by impregnating or applying a cement setting delay component to a paper towel, a cloth towel, a plastic sheet, a metal foil, and a nonwoven fabric in advance. There has been proposed a sheet and a method for treating a concrete surface in which the sheet is affixed to a formwork and concrete is driven.
Japanese Patent No. 2601368 JP-A-4-163104 JP-A-6-47725 Japanese Patent Laid-Open No. 7-206496 JP 2001-106583 A Japanese Patent Publication No.54-14120 JP-A-9-183634 JP 11-278896 A JP 11-291212 A JP 11-320522 A JP 2001-107558 A Japanese Patent No. 3285192

However, since the cement setting retarding sheet needs to be cut in advance according to the shape of a predetermined portion for treating the concrete surface, particularly when a large number of reinforcing bars or embedded members protrude from the concrete processing surface. This complicates the cutting and cutting operation of the sheet.
In addition, conventional concrete surface treatment agents and cement setting delay sheets often use organic adhesives, volatile or non-volatile organic solvents, etc. for coating film formation or sheet adhesion. This is not desirable. Furthermore, the conventional concrete surface treatment agent and cement setting delay sheet have a problem that it is difficult to control the thickness (depth) to be treated from the concrete surface, and the concrete surface treatment range is easily limited.

Therefore, the problem of the present invention is that it is excellent in environment without using an organic adhesive or an organic solvent, which has both excellent adhesiveness which is difficult to move or break by placing concrete and cement setting delay. Another object of the present invention is to provide an inorganic paint for delaying cement setting, which can easily form a coating film in any shape.
Another problem of the present invention is that mortar containing uncured cement at a predetermined location on the concrete surface can be accurately removed regardless of the shape, and color unevenness, spots, etc. are sufficiently generated on the surface other than the predetermined location. An object of the present invention is to provide an environmentally superior method of treating a concrete surface that can be suppressed and can also control the thickness (depth) of mortar removed from the surface.
Another object of the present invention is to use the above-mentioned inorganic paint for delaying cementation of the present invention to easily combine two or more hardened concretes with strong adhesive strength and environmental friendliness. Another object of the present invention is to provide a method for producing a concrete structure that can be obtained by a simple method.

According to the present invention, a paint capable of forming a coating film having a cement setting retarding property, comprising a cement setting retarding agent, an alkali silicate aqueous solution that imparts adhesiveness and film forming ability, a filler, and water An inorganic paint for setting delay is provided.
Further, according to the present invention, the step (A) of forming the coating film by applying the cement setting retarding inorganic coating at least once to a predetermined portion of the concrete casting mold, and the mold on which the coating film is formed. Step (B) in which concrete is placed and hardened in a frame, the mold is removed, the coating film component on the concrete surface and the mortar of the uncured cement part are washed with water, and bones are formed at predetermined locations on the surface of the hardened concrete. There is provided a method for treating a concrete surface comprising the step (C) of exposing the material.
Furthermore, according to the present invention, another concrete is formed using the step (A), the step (B), the step (C), and the predetermined location where the aggregate is exposed in the step (C) as a joining surface. There is provided a method for producing a concrete structure including a step (D) of placing and hardening and connecting at least two hardened concretes.

The inorganic paint for delaying cement setting of the present invention includes a cement setting retarder, an aqueous alkali silicate solution that imparts adhesiveness and film-forming ability, a filler, and water. In particular, the cement setting retarder itself is water-soluble. The alkali silicate aqueous solution exhibits air-curing properties without using an organic adhesive or an organic solvent, and has strong adhesiveness to a surface having any angle, such as a concrete casting formwork. On the other hand, the cement setting retarder is gradually added to the water of the surface layer so as to delay the hydration of the cement in the concrete surface layer part by contacting the water in the concrete by contacting with the concrete to be poured. Because it can be released, it has excellent adhesiveness that is difficult to move or break by placing concrete and cement setting delay, and is also environmentally superior. , It can be easily formed in any shape.
Therefore, the inorganic paint for delaying cement setting of the present invention exposes a part of the aggregate to the desired surface of the hardened concrete so that the appearance of the concrete, anti-slip of the concrete road surface, adhesion of the jointed surface of the concrete can be obtained. It is useful for the surface treatment of various concrete for the purpose of reinforcement and the manufacturing method of concrete structures.

The method for treating a concrete surface of the present invention includes the above steps (A) to (C), and in particular, using the inorganic paint for delaying cementation of the present invention in step (A), adhesion, cementation retarding property And because it forms a coating film excellent in environmental properties, it is possible to accurately remove mortar containing uncured cement at a predetermined location on the concrete surface in any shape, and there is uneven color or spots on the surface other than the predetermined location. It is possible to sufficiently suppress the occurrence, and in addition, the thickness (depth) of the mortar removed from the concrete surface can be controlled by controlling the number of times of applying the inorganic paint for delaying cementation of the present invention in the step (A). It can be done easily.
The method for producing a concrete structure of the present invention includes the above steps (A) to (D), and in particular, using the inorganic paint for delaying cementation of the present invention in step (A), adhesion, cementation delaying. Forming a coating film excellent in environmental properties and environmental properties, exposing the aggregate to a predetermined location by steps (B) and (C), and using the exposed aggregate as a joint surface in step (D) to perform other hardening Since it can be connected to concrete, it is possible to easily obtain a connected concrete structure in which two or more hardened concretes have strong adhesive strength and are environmentally friendly.

Hereinafter, the present invention will be described in more detail.
An inorganic paint for retarding cement setting of the present invention (hereinafter sometimes simply referred to as an inorganic paint) includes a cement retarder, an aqueous alkali silicate solution that imparts adhesiveness and film-forming ability, and a filler. Including water. Here, the inorganic coating material intends a coating material that does not substantially contain an organic adhesive or an organic solvent.
The cement setting retarder is a component that, when the inorganic coating material of the present invention is brought into contact with the concrete surface, retards the hardening of the concrete on the surface in contact with the other non-contact surface.
As such cement setting retarders, for example, usual cement setting retarders such as perfluorinated salts, saccharides, oxycarboxylic acids, oxycarboxylates and the like can be used. In view of a long delay holding time, use of oxycarboxylates such as sodium gluconate is preferred.

The alkali silicate aqueous solution is a component that exhibits adhesion to the surface of a formwork or a concrete surface and a film-forming ability on the surface of the inorganic paint of the present invention, and exhibits air-curing properties. It is a water-soluble component that can be washed with water after forming the coating film.
Examples of such an aqueous alkali silicate solution include an aqueous solution of sodium silicate and / or potassium silicate. Specifically, a sodium silicate aqueous solution is preferably a Na ₂ O · nSiO ₂ aqueous solution generally called water glass. Here, n is preferably 2 or more, particularly 3 or more, but the upper limit thereof is not particularly limited as long as it is a range showing water solubility, and is usually about 4. As the potassium silicate aqueous solution, a K ₂ O · nSiO ₂ aqueous solution is preferable. Here, n is preferably 2 or more, particularly 3 or more, but the upper limit thereof is not particularly limited as long as it is a range showing water solubility, and is usually about 4. Among these alkali silicate aqueous solutions, the use of Na ₂ O · nSiO ₂ water glass is particularly preferable in terms of excellent adhesion, coating film forming ability, and economic efficiency.

In the inorganic paint of the present invention, the filler is a component that imparts ease of application of the paint and is necessary for adjusting the thickness of the coating film after application, and is usually an inorganic substance such as mineral powder. Powder can be used.
Examples of such fillers include limestone powder, bentonite, silica stone powder, and crushed stone powder. The filler preferably has a large specific surface area for coating properties, dispersibility, and separation resistance of the paint, and it is usually desirable to use a filler having a specific surface area of 4000 cm ² / g or more.
The particle size of the filler is usually a particle size passing through 200 mesh, preferably a particle size passing through a mesh of 325 or more, but is not particularly limited as long as it can be dispersed in the inorganic paint of the present invention.

The inorganic paint of the present invention can be made into a paint by fluidizing the above components with water. The water is not particularly limited, and tap water can be used.
The inorganic paint of the present invention preferably contains a thickener in order to maintain the dispersibility of the filler in an aqueous solution state.
Examples of the thickener include a cellulose thickener, an acrylic thickener, a glycol thickener, and the like. From the viewpoint that the dispersibility of the filler can be easily controlled, Use is preferred.

In the inorganic paint of the present invention, the content ratio of each of the above components and the optional components described later achieves the desired effect of the present invention so that the total amount of each component to be contained is 100% by weight with respect to the total amount of the paint. Therefore, it can select suitably.
The content ratio of the cement setting retarder can be appropriately selected so as to obtain the desired effect, and is not particularly limited. For example, it is usually 0.5 to 20.0% by weight, preferably 1.0 to 15.0% by weight, based on the total amount of the inorganic paint. If the ratio is small, the desired cement setting retarding action may be insufficient. On the other hand, if the ratio is large, the retarder flows together with the concrete to drive the concrete, and There may be uneven color and spots on the concrete surface.

The content ratio of the aqueous alkali silicate solution is not particularly limited as long as it can form a film with good adhesion by coating. For example, alkali silicates such as sodium silicate and / or potassium silicate (SiO ₂ amount + Na ₂ O amount) and / or (SiO ₂ amount + K ₂ O amount) The amount is usually 2.0 to 20.0% by weight, preferably 4.0 to 13.5% by weight. When the ratio is small, it becomes difficult to impart desired adhesiveness and film-forming ability to the obtained coating film, whereas when the ratio is large, the adhesion of the resulting coating film is too strong, There is a risk that the surface treatment effect may be reduced because the release of the retarder is hindered in the concrete.
Moreover, the content rate of the said alkali silicate aqueous solution is 5.0-30.0 weight% normally with respect to the coating-material whole quantity, Preferably it is 10.0-30.0 weight%. When the ratio is small, it becomes difficult to impart desired adhesiveness and film-forming ability to the obtained coating film. On the other hand, when the ratio is large, the adhesion of the resulting coating film is too strong. In addition, the release of the retarder to the concrete may be hindered and the surface treatment effect may be reduced.

The content rate of the said filler is 20.0-70.0 weight% normally with respect to the coating-material whole quantity, Preferably it is 30.0-65.0 weight%. If the ratio is less than 20.0% by weight, there is a risk of deterioration in workability such as a large amount of sagging when the resulting paint is applied, and further, it becomes difficult to ensure the desired film thickness and the desired cement setting delaying action. Is difficult to obtain. On the other hand, if it exceeds 70.0% by weight, the paint becomes hard and difficult to apply.
The water content in the paint of the present invention includes the amount of water contained in the alkali silicate aqueous solution and the liquid cement setting retarder. The amount of water added at the time of mixing each of the above components can be determined by appropriately selecting an amount such that the amount of the alkali silicate and the amount of the filler are in the above-mentioned ratio, for example, in a state where the obtained paint can be applied. .

  When the inorganic paint of the present invention contains a thickener, the content of the thickener can be appropriately selected according to the type of the thickener so that the desired filler dispersibility is good. 0.002 to 2.0% by weight, preferably 0.005 to 1.0% by weight. If the ratio is less than 0.002% by weight, it is difficult to obtain the desired effect of containing a thickener. On the other hand, if it exceeds 2.0% by weight, the viscosity of the paint itself increases, and the paint is uniformly applied. May become complicated.

In addition to the above-described components, the inorganic coating material of the present invention may further contain various additives and the like in order to obtain other effects as long as the desired effects of the present invention are not impaired.
Examples of the additive include, but are not limited to, pigments, pigments, dyes, and inks. By adding these additives, the surface of the concrete to be treated is colored, and the treatment range at the time of washing with water can be easily understood.
The various additives as such optional components can be appropriately selected so that the desired effect is obtained, but in order to obtain the desired effect of the present invention, the total amount of the additive is It is preferable to make it contain so that it may not exceed 10 weight% with respect to the coating-material whole quantity.

  The method for treating a concrete surface of the present invention comprises a step (A) of forming the coating film by applying the above-described inorganic coating composition of the present invention at least once to a predetermined portion of a concrete casting mold, and forming the coating film. Placing the concrete in the mold, and removing the mold (B), and removing the mold, washing the coating component on the concrete surface and the mortar of the uncured cement part with water, at a predetermined location on the surface of the hardened concrete In addition to the steps (A) to (C), the method for producing a concrete structure of the present invention includes a step (C) for exposing the aggregate, and further includes a predetermined surface where the aggregate is exposed. And (D) including placing and solidifying another concrete and connecting at least two hardened concretes.

In the step (A), the formwork can be a formwork of a desired form because the inorganic paint of the present invention can be easily applied in any shape and inclined portion, for example, in concrete. It may be a formwork having holes or the like through which reinforcing bars or steel frames are arranged.
In step (A), the location where the inorganic paint of the present invention is applied is not particularly limited as long as it delays the cement setting on the concrete surface and forms the inner surface of the mold corresponding to the predetermined location where the exposure of the aggregate is desired. Moreover, it is also possible to apply | coat directly on the concrete upper surface etc. in which a formwork does not exist.
The number of times of application can be appropriately selected according to the desired depth of the concrete surface to be treated and the control of the cement setting delay period.

The casting of the concrete cast in the step (B) can be performed when the inorganic coating material of the present invention forms a coating film in the step (A) and is in a cured state. The film formation time varies depending on the environmental temperature, humidity and the like, but is usually about 30 to 120 minutes.
In the step (B), the curing period of the concrete can be appropriately selected according to the type, shape, size, etc. of the concrete, and may be a period that can be cured to the extent that the desired strength of the concrete can be secured.

  In the step (C), washing with water can be performed by, for example, a high-pressure water washing machine or a brush. At this time, the inorganic coating material of the present invention does not substantially contain an organic adhesive, and further does not substantially contain an organic solvent, and contains the above-mentioned water-soluble alkali silicate aqueous solution as an adhesive component. Therefore, it is environmentally friendly, and furthermore, the coating film component and the uncured cement part can be easily removed.

  The step (D) can be performed by providing a formwork or the like by a known concrete connection technique using the predetermined location where the aggregate is exposed as a joint surface. At this time, various concrete structures can be manufactured by applying the inorganic coating material of the present invention to a newly formed concrete formwork and further repeating the steps (A) to (D).

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these.
Examples 1-15 and Comparative Examples 1-2
(Preparation of inorganic paint for delaying cementation)
Each component having the composition shown in Table 1 was mixed by a grout mixer to prepare an inorganic paint for delaying cement setting. In addition, each component in Table 1 and its abbreviation are as follows.
W: tap water,
GR: Oxycarboxylates cement setting retarder (trade name sodium gluconate (25K) M, crystal, manufactured by Fuso Chemical Industries),
FR: Sulfur fluoride salt cement retarder (trade name: Leo retard, liquid, manufactured by Pozzolith Products)
WG1: Water glass No. 1 (trade name J sodium silicate No. 1, molar ratio (Na ₂ O / SiO ₂ ) = 2.15, moisture content 52.5%, manufactured by Nippon Chemical Industry Co., Ltd.)
WG2: Water glass No. 2 (trade name J sodium silicate No. 2, molar ratio (Na ₂ O / SiO ₂ ) = 2.60, moisture content 59.5%, manufactured by Nippon Chemical Industry Co., Ltd.)
WG3: Water glass No. 3 (trade name J sodium silicate No. 3, molar ratio (Na ₂ O / SiO ₂ ) = 3.18, moisture content 61.5%, manufactured by Nippon Chemical Industry Co., Ltd.)
F200: Limestone fine powder (Trade name: Industrial Tancar 200 mesh, manufactured by Yoshizawa Lime Industry)
F325: Limestone fine powder (trade name industrial tancal 325 mesh, manufactured by Yoshizawa Lime Industry)
B: Bentonite (product name Asama, manufactured by Hojun Co.)
SV: Cellulosic thickener (trade name SFCA2000, manufactured by Shin-Etsu Chemical Co., Ltd.)

(Performance confirmation test of inorganic paint for cement setting delay)
In order to confirm the performance of each paint prepared as described above, the following tests and measurements were performed. The results are shown in Table 2. In addition, Example 14 and Example 15 are the examples which used what was prepared in Example 1 as a coating material, and made the number of application layers into 2 layers and 3 layers, respectively.
(1) Coating workability test A polished steel plate test plate specified in `` Standard test plate for testing JIS K5600-1-4 '' is installed in the vertical direction, paint is applied on it, and paint is easy to adhere. The presence or absence of sagging was judged. The ease of application was evaluated in three stages: excellent, good and impossible.
(2) Coating thickness The coating thickness was applied in accordance with “Test plate coating (brush coating) JIS K5600-1-5”.
(3) Drying time of coating film It was performed according to “Surface drying property (Barotini method) JIS K5600-3-2”.
(4) Adhesive strength of the coating film on the steel sheet It was performed in accordance with “Adhesion (pull-off method) JIS K5600-5-7”.
(5) Thickness of concrete washed out Prepared paint is applied once to the vertical surface of the steel formwork, and after the paint has dried, the concrete is driven in. After curing the concrete at 20 ° C for one day, demolding is performed. The concrete surface mortar in contact with the paint was washed out with a high-pressure water washer, and the average depth of the mortar washed from the concrete surface was measured as the concrete washout thickness.
(6) Number of days allowed for washing out The number of days allowed for washing out was confirmed as the maximum number of days that the mortar on the concrete surface in contact with the paint can be washed out with a high-pressure water washer.
(7) Effect of the washed-out portion on the adjacent portion The presence of phenomena such as aggregate exposure and uneven color on the concrete surface adjacent to the washed-out portion was visually observed.
(8) using a beating joint surface of the bending strength concrete achievement rate flexural strength 6.34N / mm ² of, when fabricating a height 100 mm, width 100 mm, prismatic specimen length 200 mm, 1 single vertical end faces thereof Was treated with a test paint as a vertical joint surface, and after 8 days of age, the same concrete was used for jointing to produce a prismatic specimen having a height of 100 mm, a width of 100 mm, and a length of 400 mm. This specimen with a vertical joint surface at the center was subjected to air curing at 20 ° C. for 28 days, and then the bending strength of the joint surface was measured according to “Concrete bending strength test method JIS A 1106”. The ratio between the measured bending strength and the bending strength of the concrete was defined as the achievement rate of the bending strength of the joint surface.

Claims (7)

A paint capable of forming a coating film having a cement setting retarding property,
Cement setting retarder, an inorganic paint for delaying cement setting, including an aqueous alkali silicate solution that imparts adhesion and film-forming ability, a filler, and water. The cement setting retarder is selected from the group consisting of fluorinated salts, sugars, oxycarboxylic acids, oxycarboxylates or a mixture of two or more thereof, and the aqueous alkali silicate solution is sodium silicate and / or silicic acid The inorganic paint for cement setting delay according to claim 1, which is an aqueous solution of potassium, the filler is an inorganic powder having a specific surface area of 4000 cm ² / g or more, and the water is tap water.   The inorganic paint for cement setting delay according to claim 1 or 2, further comprising a thickener for maintaining dispersibility of the filler.   The ratio of the alkali silicate aqueous solution is 2.0 to 20.0% by weight in terms of the amount of alkali silicate contained with respect to the total amount of the inorganic paint for cement setting delay, and the ratio of the filler is 20 The inorganic paint for delaying cementation settling according to claim 1 or 2, which is 0.0 to 70.0% by weight.   The ratio of the alkali silicate aqueous solution is 2.0 to 20.0% by weight in terms of the amount of alkali silicate contained with respect to the total amount of the inorganic paint for cement setting delay, and the ratio of the filler is 20 The inorganic paint for cement setting delay according to claim 3, wherein the content is 0.0 to 70.0% by weight, and the proportion of the thickener is 0.002 to 2.0% by weight. Applying the inorganic paint for delaying cementation according to any one of claims 1 to 5 to a predetermined part of a concrete casting form, and forming a coating film (A);
Placing concrete in the formwork in which the coating film is formed, and solidifying (B),
Removing the mold, washing the coating component on the concrete surface and the mortar of the uncured cement portion with water, and exposing the aggregate to a predetermined location on the surface of the hardened concrete (C). . Applying the inorganic paint for delaying cementation according to any one of claims 1 to 5 to a predetermined part of a concrete casting form, and forming a coating film (A);
Placing the concrete in the formwork on which the coating film is formed and curing (B);
Removing the mold, washing the mortar of the coating film component and uncured cement portion on the concrete surface with water, exposing the aggregate to a predetermined portion of the surface of the hardened concrete (C), and
A method for producing a concrete structure, which includes a step (D) of placing and hardening another concrete using a predetermined portion where the aggregate is exposed as a joining surface and connecting at least two hardened concretes.