Components for hydraulic materials

Abstract

To provide a composition for a hydraulic material, capable of forming a dense structure on a surface layer of concrete with a shrinkage reducing effect, thereby enhancing the protective effect of concrete and improving its durability performance.SOLUTION: A composition for a hydraulic material comprises: (A) at least one compound represented by the following general formula (1), R1O-(AO)n-H; and (B) an isothiazoline compound. (In the formula (1), R1 represents a 1-8C alkyl group; AO represents a 2-4C oxyalkylene group; and n represents an integer between 1 and 11).SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a composition for hydraulic materials such as mortar and concrete. [Background technology]

[0002] Hardened concrete is a hydraulic composition formed by the reaction of water and cement. During the hardening process, water is lost due to evaporation or hydration, leading to concrete shrinkage. This shrinkage of hardened concrete causes strain within the structural member, eventually leading to cracks on the member surface, accelerating the deterioration of the concrete structure due to water leakage, and potentially resulting in structural defects.

[0003] To address concrete shrinkage during the hardening process, the use of shrinkage reducing agents has been proposed. For example, Patent Document 1 describes the use of alkylene oxide adducts of lower alcohols having 1 to 4 carbon atoms as a shrinkage reducing agent for cement. Patent Document 2 describes that a shrinkage reducing agent with superior shrinkage reduction effect can be obtained by optimizing the copolymerization ratio of ethylene oxide and propylene oxide in the alkylene oxide adduct of lower alcohol. Furthermore, Patent Document 3 describes that a decrease in the strength of the hardened product can be prevented by improving the dispersion state of the shrinkage reducing agent in the cement slurry and reducing foaming properties. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Special Publication No. 56-51148 [Patent Document 2] Japanese Patent Publication No. 2001-163653 [Patent Document 3] Japanese Patent Publication No. 2003-171155 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0005] The shrinkage-reducing agents for cement proposed so far have primarily aimed to reduce the shrinkage of hardened cement and suppress the decrease in strength of the hardened material. However, they have not provided sufficient curing effect to form a dense structure on the surface of the concrete, resulting in a problem of reduced durability.

[0006] The present invention aims to provide a concrete curing agent that, while having a shrinkage-reducing effect, can form a dense structure on the surface of concrete, thereby enhancing the protective effect of the concrete and improving its durability. [Means for solving the problem]

[0007] As a result of investigating and researching the above-mentioned problems, the inventors have found that by combining a shrinkage-reducing agent of a specific structure with an isothiazolin compound to create a composition for hydraulic materials, and by applying this to a cement-based hardened body, the surface air permeability coefficient of the hardened body can be reduced, thus completing the present invention.

[0008] In other words, the present invention covers the following [1] to [7]. [1] (A) At least one compound represented by the following general formula (1), (B) containing isothiazolin compounds, Hydraulic material composition. R 1 O-(AO) n -H (1) (In formula (1), R 1 (where represents an alkyl group with 1 to 8 carbon atoms, AO represents an oxyalkylene group with 2 to 4 carbon atoms, and n represents an integer from 1 to 11.) [2] The hydraulic material composition according to [1], wherein the (B) isothiazolin compound is a compound represented by the following general formula (2) or the following general formula (3). [ka] (In formula (2), R 2represents a hydrogen atom or an optionally substituted hydrocarbon group, R 3 and R 4 each independently represent a hydrogen atom, a halogen atom, or an optionally substituted hydrocarbon group.) [Chemical formula] (In formula (3), R 5 represents a hydrogen atom or a hydrocarbon group which may have a substituent, R 6 each independently represents an aliphatic group or an aromatic group which may have a substituent. m represents an integer from 0 to 4.) [3] The mass ratio of the component (A) to the component (B) is 90:10 to 99.99:0.01, The composition for hydraulic materials according to [1]. [4] A concrete curing agent comprising the composition for hydraulic materials according to any one of [1] to [3]. [5] A method for curing cement mortar or concrete, characterized in that the concrete curing agent according to [4] is applied to the surface of a cement-based hardened body. [6] A cement-based hardened body containing the composition for hydraulic materials according to any one of [1] to [3]. [[ID=4,0]] [7] A cement-based hardened body in which the concrete curing agent according to [4] is impregnated from the surface to the surface layer. [Advantages of the Invention]

[0009] The composition for hydraulic materials of the present invention can provide a hardened body having increased compressive strength, reduced drying shrinkage, and reduced surface air permeability coefficient in a cement-based hardened body to which it is applied. [[ID=,51]] Further, according to the present invention, the formation of a densified structure in the surface layer portion of a cement-based hardened body to which it is applied It is possible to provide a cured body that is promoted, can be expected to have a reduced surface air permeability coefficient, and can contribute to preventing the deterioration of concrete caused by the intrusion of gas, ions, etc. from the surface layer.

[0010] In addition, cement-based cured bodies usually ensure durability by taking the "cover" distance to the thickness of the member and the reinforcing bars. However, by forming a dense layer on the surface layer of the cured body, sufficient strength improvement can be expected even in the concrete of thin members. That is, by promoting the formation of a densified structure in the surface layer part of the cured body by applying the composition for hydraulic materials of the present invention, it can be expected to lead to a reduction in the construction volume and a reduction in the environmental load.

Mode for Carrying Out the Invention

[0011] The present invention relates to a composition for hydraulic materials containing an alkylene oxide adduct of a lower alcohol and an isothiazoline-based compound, and also relates to a cement-based cured body and a curing method to which this is applied. The inventors of the present invention have found that by blending a composition for hydraulic materials combined with an alkylene oxide adduct of a lower alcohol and an isothiazoline-based compound, it is possible to contribute to the surprising effect that the surface air permeability coefficient becomes small in a cement-based cured body to which the composition for hydraulic materials is applied, that is, it can have a function as a surface densifying agent. Hereinafter, the present invention will be described in more detail.

[0012] [Composition for Hydraulic Materials] <(A) Compound Represented by General Formula (1)> The component (A) constituting the composition for hydraulic materials according to the present invention is a compound (alkylene oxide adduct of a lower alcohol) represented by the following general formula (1). In the present invention, the component (A) has a function as a shrinkage reducing agent, can also improve the separability from the component (B) described later, and can also strengthen the compatibility and even the one-component property of both.

[0013] R 1 O-(AO) n -H (1) (In Formula (1), R1 (where represents an alkyl group with 1 to 8 carbon atoms, AO represents an oxyalkylene group with 2 to 4 carbon atoms, and n represents an integer from 1 to 11.)

[0014] In the above general formula (1), R 1 represents an alkyl group having 1 to 8 carbon atoms, specifically linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, and n-octyl groups; and branched alkyl groups such as isopropyl, sec-butyl, tert-butyl, neopentyl, 1-ethylpropyl, and 2-ethylhexyl groups. Of these, alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, and n-butyl groups, are preferred from the viewpoint of compatibility with component (B).

[0015] Furthermore, in the general formula (1) above, AO represents an oxyalkylene group having 2 to 4 carbon atoms, specifically including an ethylene oxy group, a propylene oxy group, and a butylene oxy group. n is the number of moles of oxyalkylene group AO added, and represents an integer from 1 to 11. If n is 2 or greater, the oxyalkylene groups may be the same or different. If (AO)n consists of two or more alkylene oxy groups, either block addition or random addition may be performed.

[0016] Specific examples of the compound represented by the general formula (1) include polyethylene glycol polypropylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polyethylene glycol polypropylene glycol monoethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol polypropylene glycol monomethyl ether. Examples of polyoxyalkylene alkyl ethers include polypropyl ether, polyethylene glycol monopropyl ether, polyethylene glycol polypropylene glycol monobutyl ether, and polyethylene glycol monobutyl ether.

[0017] <(B) Isothiazoline compounds> Component (B) of the hydraulic material composition according to the present invention is an isothiazolin compound. The above-mentioned isothiazolin compounds can preferably be compounds represented by the following general formula (2) or the following general formula (3). [ka] (In formula (2), R 2 represents a hydrogen atom or an optionally substituted hydrocarbon group, R 3 and R 4 Each of these independently represents a hydrogen atom, a halogen atom, or an optionally substituted hydrocarbon group. [ka] (In formula (3), R 5 This represents a hydrogen atom or a hydrocarbon group which may have substituents. R 6 Each of these independently represents an aliphatic group or an aromatic group that may have substituents. (m is an integer from 0 to 4.)

[0018] In the above general formula (2), R 2 R represents a hydrogen atom or an optionally substituted hydrocarbon group. Also, in the general formula (2) above, 3 and R 4 Each of these independently represents a hydrogen atom, a halogen atom, or an optionally substituted hydrocarbon group. In the above general formula (3), R 5 represents a hydrogen atom or a hydrocarbon group which may have substituents. In general formula (3) above, m is substituent R 6 The number is an integer between 0 and 4, R 6 If multiple instances exist, each independently represents an aliphatic group or aromatic group that may have substituents.

[0019] Examples of the hydrocarbon groups include alkyl groups having 1 to 30 carbon atoms; aromatic groups having 6 to 18 carbon atoms and a benzene ring, such as phenyl groups, alkylphenyl groups, phenyl groups substituted with (alkyl)phenyl groups, and naphthyl groups; and alkenyl groups having 2 to 18 carbon atoms, such as oleyl groups and linoleyl groups. Among these, alkyl groups having 1 to 30 carbon atoms are preferred hydrocarbon groups. Examples of aliphatic groups include alkyl groups having 1 to 30 carbon atoms, and examples of aromatic groups include aromatic groups having 6 to 18 carbon atoms. Examples of alkyl groups with 1 to 30 carbon atoms include methyl, ethyl, and n-propyl groups. Examples include linear alkyl groups such as pyr group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, n-tetradecyl group, n-hexadecyl group, and n-octadecyl group; and branched alkyl groups such as isopropyl group, sec-butyl group, tert-butyl group, neopentyl group, 1-ethylpropyl group, 1-heptyldecyl group, and 2-ethylhexyl group. Of these, alkyl groups having 1 to 8 carbon atoms are preferred. Aromatic groups with 6 to 18 carbon atoms include, specifically, phenyl, naphthyl, tolyl, xylyl, coumenyl, mesityl, and biphenyl groups. Examples of substituents on the hydrocarbon group include halogen atoms and hydroxyl groups.

[0020] Specific examples of isothiazoline compounds represented by the above general formula (2) or general formula (3) include, but are not limited to, 2-methyl-4-isothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 4-chloro-2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 5-chloro-2-n-octyl-4-isothiazolin-3-one, and 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, 1,2-benzoisothiazolin-3-one, and Nn-butyl-1,2-benzoisothiazolin-3-one. Among these, compounds that do not contain chloro atoms are preferred from the viewpoint of pH dependence, and for example, 2-n-octyl-4-isothiazolin-3-one (see structural formula below) is preferred. [ka]

[0021] In the hydraulic material composition according to the present invention, the blending ratio of (A) a compound represented by general formula (1) and (B) an isothiazolinoline compound can be used in the range of A:B = 90 to 10:99.99 to 0.01 by mass ratio, and more preferably in the range of 99:1 to 99.95:0.05.

[0022] In the hydraulic material composition used in the present invention, in addition to (A) the compound represented by general formula (1) and (B) the isothiazolinoline compound, other components commonly used in hydraulic material compositions may also be included. Other possible ingredients include commonly used waterproofing agents, water repellents, defoaming agents, viscosity stabilizers, preservatives, fungicides, disinfectants, rust inhibitors, and anti-leaching agents.

[0023] [Curing methods for cement-based hardened bodies and cement mortar or concrete] In the present invention, the cement-based hardened body is a cement mortar obtained by mixing cement with fine aggregate and water, or a hardened concrete body further containing coarse aggregate, and may also contain one or more admixtures selected from various types. The above-mentioned cements can be any cement that has hydraulic properties, and examples include Portland cement such as ordinary Portland cement and rapid-hardening Portland cement, eco-cement, blended cements such as blast furnace cement and fly ash cement, alumina cement, and ultrafast-setting cements such as "Super Jet Cement" (product name) manufactured by Taiheiyo Cement Corporation and "Jet Cement" (product name) manufactured by Sumitomo Osaka Cement Co., Ltd., and one or more of these can be used. In addition to the above-mentioned cements, admixtures that can be added to the cements include blast furnace slag fine powder, fly ash, silica fume, and calcium carbonate. It may contain fine powders, leavening agents, gypsum, etc.

[0024] The hydraulic material composition of the present invention can be used as a concrete curing agent. That is, a concrete curing agent comprising the hydraulic material composition is also subject to the present invention, and other components that can be incorporated into the hydraulic material composition can also be incorporated into the concrete curing agent in the same manner. By applying the hydraulic material composition (i.e., concrete curing agent) to the surface of a hardened or semi-hardened cement-based hardened body (a hardened cement mortar or concrete), the hydraulic material composition (concrete curing agent) is impregnated from the surface to the surface layer of the hardened body, and a cement-based hardened body of the present invention can be obtained in which a densified structure is formed on the surface layer. Specifically, the hydraulic material composition (concrete curing agent) is applied to the hardened body as a finishing aid during the finishing of the cement-based hardened body, or after the hardened cement-based hardened body has been demolded. The application method for the hydraulic material composition (concrete curing agent) is not particularly limited as long as it can be applied to the surface of a cement-based hardened body. It can be applied by spraying, coating, spraying, or misting, and is preferably a method that allows for uniform application to the surface of the cement-based hardened body, such as coating with a roller, brush, or sprayer.

[0025] When applying the hydraulic material composition according to the present invention to a hardened concrete body as a concrete curing agent, the amount used is not particularly limited, but for example, on the surface of the hardened body, 1 m 2 It can be used in a range of 50 to 300 g per square meter, preferably 100 to 200 g / m². 2 It can be used within the following range: 50g / m 2 Using less may make it difficult to achieve smooth trowel application and prevent moisture loss during finishing, so 300g / m 2 If the amount exceeds a certain limit, it may be considered excessive and could lead to a decrease in adhesive strength. Furthermore, the cement-based hardened materials covered include both mortar and concrete.

[0026] Furthermore, the hydraulic material composition of the present invention can also be used by mixing it with mortar or concrete. When used by mixing, the amount added is preferably 0.1 to 10 parts by mass per 100 parts by mass of cement in the mortar or concrete. [Examples]

[0027] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0028] [Composition for hydraulic materials] The hydraulic material compositions I to VI (combinations of (A) a compound represented by general formula (1) and (B) an isothiazolin compound) used in the following examples and comparative examples are as follows. [Table 1]

[0029] [Manufacturing of fresh concrete for testing] The target values ​​for fresh concrete were a slump of 15 ± 2.5 cm and an air content of 4.5 ± 1.5%. The mix design for the test concrete is shown in Table 2. In a constant temperature room at 20°C and 80%RH, a pan-type mixer with a nominal capacity of 55L was used. First, cement, fine aggregate, and coarse aggregate were added to the mixer and mixed for 30 seconds. Then, mixing water, water-reducing agent, and air-regulating agent were added and mixed for 120 seconds. After that, the mixture was discharged and subjected to the following tests [(1)~(3)]. [Table 2]

[0030] [Concrete evaluation test using a composition for hydraulic materials] The fresh concrete prepared according to the above procedure is poured into formwork of the dimensions used for each test, removed after 24 hours of water injection, and each hydraulic material composition (I-VI) is uniformly applied to the surface of the test specimen as shown in Table 2 (150g / m²). 2 The following steps were taken: After application, the material was cured in the air at a temperature of 20°C and a humidity of 60% until the specified curing age was reached.

[0031] (1) Compression strength test Compressive strength was measured in accordance with JIS A 1108 "Test Method for Compressive Strength of Concrete". Test specimens (φ10cm × 20cm) were used for compressive strength testing, and the specimens were cured at 20°C and 60% RH for up to 28 days. The compressive strength of each specimen was then measured.

[0032] (2) Drying shrinkage test The drying shrinkage test was conducted in accordance with JIS A 1129-2 "Method for measuring length change of mortar and concrete - Part 2: Contact gauge method". For the drying shrinkage test, the test specimens were 30cm x 30cm x 6cm (flat plate specimens). They were demolded 24 hours after casting, and each hydraulic material composition was applied only to the cast surface (top surface), while the other five surfaces were covered with aluminum tape. In the test, a hydraulic material composition was applied to the test surface, which was the top surface of the cast concrete. A gauge plug was then attached, and the length and mass of the test specimen were measured (reference values). The specimen was then cured at 20°C and 60% RH, and the length and mass were measured again after 182 days to determine the change in length and the rate of mass loss.

[0033] (3) Surface air permeability coefficient The surface air permeability coefficient kT value was measured using the torrent method. The test was conducted using a 10cm × 10cm × 40cm specimen, cured at 20°C and 60% RH, and measured at 28 days of age.

[0034] The results obtained are shown in Table 3. [Table 3]

[0035] As shown in Table 3, compared to the uncoated specimen (Comparative Example 1), the application of hydraulic material compositions II to VI resulted in improved compressive strength, reduced length change and mass loss rate (drying shrinkage), and a lower surface air permeability coefficient (Examples 1 to 5), confirming that a high curing effect can be obtained by applying the hydraulic material compositions of the present invention. Note that in the specimen coated with hydraulic material composition I without isothiazolin compounds (Comparative Example 2), improvements were observed in compressive strength, drying shrinkage, and surface air permeability coefficient compared to the uncoated specimen (Comparative Example 1), but the reduction in surface air permeability coefficient was significantly inferior compared to hydraulic material compositions II to VI (Examples 1 to 5).

[0036] As described above, the hydraulic material composition of the present invention, which combines (A) a specific compound represented by general formula (1) and (B) an isothiazolin compound, increases compressive strength and reduces drying shrinkage. Furthermore, it was confirmed that a cured body with a reduced surface air permeability coefficient can be provided.

Claims

1. (A) At least one compound represented by the following general formula (1), (B) Contains an isothiazolin compound represented by the following general formula (2) or general formula (3) in a mass ratio of (A):(B) = 90:10 to 99.99:0.

01. Composition for hydraulic materials. R １ O-(AO) ｎ -+ (1) (In formula (1), R １ (where represents an alkyl group with 1 to 4 carbon atoms, AO represents an oxyalkylene group with 2 to 4 carbon atoms, and n represents an integer from 1 to 8.) 【Chemistry 1】 (In formula (2), R2 represents a hydrogen atom or an alkyl group having 1 to 30 carbon atoms. R3 and R4 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 30 carbon atoms. 【Chemistry 2】 (In formula (3), R5 represents a hydrogen atom or an alkyl group having 1 to 30 carbon atoms. Each R6 independently represents an alkyl group with 1 to 30 carbon atoms or an aromatic group with 6 to 18 carbon atoms. m is an integer from 0 to 4.

2. A concrete curing agent comprising the hydraulic material composition described in claim 1.

3. A method for curing cement mortar or concrete, characterized by applying the concrete curing agent described in claim 2 to the surface of a cement-based hardened body.

4. A cement-based hardened body in which the concrete curing agent described in claim 2 is impregnated from the surface to the surface layer.

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