JP5889058B2 - Cement-based cured body and cement mortar or concrete curing method - Google Patents

Description

  The present invention relates to a cement-based cured body using a curing agent for concrete containing a fatty acid ester mixture and an alkoxysilane derivative, and a method for curing cement mortar or concrete using the curing agent. Cement-based hardened body and cement mortar or concrete curing method aimed at preventing moisture from entering and escaping from the surface after casting, reducing drying shrinkage and improving durability, and preventing deterioration over a long period of time About.

In order for the cement-based hardened body to have a dense structure capable of exhibiting the required strength and durability, it is necessary to carry out sufficient curing at the initial stage of the hydration progress process to reduce shrinkage. For this reason, “JASS 5” of the Architectural Institute of Japan defines the curing period, method, and amount of drying shrinkage, and wet curing is indispensable in order to prevent rapid drying after placing the cement-based cured body.
Curing methods include a method of supplying moisture to concrete (such as underwater curing, submerged curing, watering curing, and compressing curing) and a method of preventing moisture dissipation (such as film curing and sheet curing). Underwater curing and submerged curing are the most effective wet curing, but are often difficult to perform with actual structures. On the other hand, film curing is a method in which a film curing agent is sprayed or applied on a concrete surface to form a film on the surface, thereby preventing evaporation of moisture to the outside and promoting hydration.

As the film curing agent, there are a solvent type in which a polymer or a wax is dissolved in an organic solvent, and an aqueous type in which the polymer or wax is emulsified in water, and various curing agents have been proposed (Patent Documents 1 to 3).
As a typical curing agent, there is a paraffin-based curing agent (Patent Document 2 or the like), and the paraffin-based curing agent is excellent in a curing effect that prevents evaporation of moisture in concrete or mortar and has high safety. In addition, there is no bleeding, and the finishing work of high-strength concrete with high viscosity is facilitated, and there is an effect of suppressing plastic cracks.

  In addition, it is important for the cement-based cured body not only to be dried immediately after being cast, but also to prevent drying after a long period of time. This is because if the cured body is dried over a long period of time, the member will be distorted due to shrinkage, eventually causing cracks on the member surface, promoting deterioration of the concrete structure due to water leakage, etc., which may lead to structural defects. Because there is. In addition to deterioration due to drying, for example, deterioration phenomena of cement-based hardened bodies such as alkali-aggregate reaction and salt damage can be mentioned, but these deterioration phenomena are promoted by moisture intrusion into the hardened body.

  As a measure for preventing the deterioration phenomenon, for example, Patent Document 4 proposes a water repellent composition using a fatty acid ester. In Patent Document 5, an emulsion of a saturated fatty acid ester is applied as a drying inhibitor. Various durability improvers made of silane compounds have also been proposed. For example, Patent Document 6 proposes a molded article in which an alkylpolysiloxane having water repellency is internally added, and Patent Document 7 proposes a method of impregnating a concrete surface with alkylalkoxysilane to impart water repellency. Has been. Further, as a surface impregnating agent for reducing drying shrinkage and preventing moisture from entering, Patent Document 8 proposes a mixture of an organoalkoxysilane and a glycol ether surfactant. Patent Document 9 proposes a polyalkylene oxide derivative of tetraalkoxysilane as an agent that maintains waterproofness for a long period of time and reduces drying shrinkage.

Japanese Patent Laid-Open No. 5-208879 Japanese Patent Laid-Open No. 11-21184 JP 2004-244255 A Japanese Patent Laid-Open No. 7-69696 JP 2008-273765 A JP 58-2252 A Japanese Patent Laid-Open No. 2-16186 Japanese Patent Laid-Open No. 3-93680 International Publication No. 04/108628 Pamphlet

However, when the above-mentioned conventional paraffin-based curing agent is applied with a finishing material after the curing agent is applied, the adhesion strength is reduced, and there is a concern that the finishing material may be peeled, cracked, floated, or the like. Therefore, when the finishing material is applied after the application of the paraffinic curing agent, it is necessary to remove the curing agent by ground polishing by sanding or high-pressure cleaning.
In addition, the concrete durability improvers using fatty acid ester compounds and alkoxysilanes that have been proposed so far are, as shown in the above-mentioned literature, an increase in compressive strength and water repellency by suppressing drying of the cured product. The main purpose was granting. However, although these technologies are excellent in the ability to prevent deterioration in a short period of time after placement, there is still room for improvement in securing long-term durability over 28 days of age, such as a decrease in waterproofing effect over time. there were. In addition to the long life of civil engineering structures in recent years, there is also a great demand for shrinkage reduction as a means of preventing cracks in concrete.
In addition, in terms of enhancing the functionality of the paint-type curing agent applied to the surface of the cured body, conventionally, only the surface modification of the coating film has been focused, and the cured body itself is impregnated from the surface layer of the concrete. There is still room for improvement in the technology for modifying physical properties.
The present invention sufficiently exhibits the strength of the cement-based cured body due to the curing effect, is excellent in water absorption prevention and shrinkage reduction, has resistance to the occurrence of cracks on the surface, and further invades carbon dioxide and chloride ions. An object of the present invention is to provide a cement-based cured body, a cement mortar, and a curing method for concrete, which can be suppressed and concrete deterioration due to these can be reduced.

  As a result of studying the above-mentioned problems and conducting research, the present inventors applied a curing agent containing a fatty acid ester mixture having a specific configuration and an alkoxysilane derivative to a cement-based hardened body, thereby causing concrete shrinkage after hardening. It was found that the strength development of the hardened concrete is suppressed, and the reduction of drying shrinkage and water absorption prevention that occur after use over time can be maintained over a long period of time.

That is, the present invention includes a fatty acid ester mixture (A) represented by the following general formula (1), an alkoxysilane, a hydrolyzate thereof or a polycondensate thereof, and a polyoxy represented by the following general formula (2). The present invention relates to a hardened cementitious material obtained by impregnating a surface layer with a curing agent for concrete containing an alkoxysilane derivative (B) obtained by reacting an alkylene compound.
R ¹ CO—O—R ² (1)
(In the formula, R ¹ CO represents a fatty acid residue having 12 to 24 carbon atoms, and the proportion of long-chain saturated fatty acid residues having 16 to 24 carbon atoms in the total fatty acid residues is 3 to 40% by mass, The proportion of long-chain monounsaturated fatty acid residues having 16 to 24 carbon atoms is 30 to 50% by mass, the proportion of long-chain diunsaturated fatty acid residues having 16 to 24 carbon atoms is 20 to 40% by mass, and a percentage ratio of 0 mass% of long chain tri-unsaturated fatty acid residues of carbon atoms 16 to 24, R ² is 1 to 8 carbon atoms
Represents an alkyl group. )
R ³ O— (AO) _n —H (2)
(In the formula, R ³ represents a hydrocarbon group having 1 to 18 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents an integer of 1 to 20).

The present invention also includes a fatty acid ester mixture (A) represented by the following general formula (1), an alkoxysilane, a hydrolyzate thereof or a polycondensate thereof, and a polyoxyalkylene represented by the following general formula (2). The present invention relates to a method for curing cement mortar or concrete, characterized in that a concrete curing agent containing an alkoxysilane derivative (B) obtained by reacting a compound is applied to the surface of a cement-based cured body.
R ¹ CO—O—R ² (1)
(In the formula, R ¹ CO represents a fatty acid residue having 12 to 24 carbon atoms, and the proportion of long-chain saturated fatty acid residues having 16 to 24 carbon atoms in the total fatty acid residues is 3 to 40% by mass, The proportion of long-chain monounsaturated fatty acid residues having 16 to 24 carbon atoms is 30 to 50% by mass, the proportion of long-chain diunsaturated fatty acid residues having 16 to 24 carbon atoms is 20 to 40% by mass, and a percentage ratio of 0 mass% of long chain tri-unsaturated fatty acid residues of carbon atoms 16 to 24, R ² is 1 to 8 carbon atoms
Represents an alkyl group. )
R ³ O— (AO) _n —H (2)
(In the formula, R ³ represents a hydrocarbon group having 1 to 18 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents an integer of 1 to 20).

In the curing method of the cement-based cured body and the cement mortar or concrete, in the fatty acid ester mixture (A) represented by the general formula (1), R ¹ CO is a C 18 carbon atom in the total fatty acid residue. The proportion of long-chain saturated fatty acid residues is less than 10% by mass, the proportion of long-chain monounsaturated fatty acid residues having 18 carbon atoms is 30-50% by mass, and the long-chain diunsaturated fatty acid residues having 18 carbon atoms Is more preferably 20 to 40% by mass.

ADVANTAGE OF THE INVENTION According to this invention, it can provide the cement-type hardened | cured material which has high compressive strength, drying shrinkage was reduced, and also the prevention of drying and waterproofing were maintained over a long period of time. And according to this invention, since it becomes a hardening body which also suppressed the penetration | invasion of the carbon dioxide gas and chloride ion from the surface, the hardening body which can contribute to the concrete deterioration prevention by these penetration | invasion can be provided.
In addition, by applying the cement mortar or concrete curing method of the present invention, at the initial stage of application, the cured body is prevented from drying, strength development is promoted, shrinkage is reduced, and the cured body is prevented from drying over a long period of time. Waterproofness can be maintained.

FIG. 1 is a view showing a front view (FIG. 1 (A)) of a test plate used in a water absorption waterproof performance test and a side view (FIG. 1 (B)) in which a glass instrument is installed. FIG. 2 is a front view (FIG. 2 (A)), a side view (FIG. 2 (B)), and a perspective view (FIG. 2 (FIG. 2 (B))) of a test plate installation frame for leaving the test plate used in the water absorption waterproof performance test outdoors. C)).

The present invention is characterized in that a concrete curing agent containing a fatty acid ester mixture having a specific configuration and an alkoxysilane derivative is applied to a cement-based cured body.
Hereinafter, the present invention will be described in more detail.

[Curing agent for concrete]
<(A) Fatty acid ester mixture represented by the general formula (1)>
In the present invention, the (A) fatty acid ester used in the concrete curing agent is a fatty acid ester represented by the following general formula (1).
R ¹ CO—O—R ² (1)
(In the formula, R ¹ CO represents a fatty acid residue having 12 to 24 carbon atoms, and the proportion of long-chain saturated fatty acid residues having 16 to 24 carbon atoms in the total fatty acid residues is 3 to 40% by mass, The proportion of long-chain monounsaturated fatty acid residues having 16 to 24 carbon atoms is 30 to 50% by mass, the proportion of long-chain diunsaturated fatty acid residues having 16 to 24 carbon atoms is 20 to 40% by mass, and a percentage ratio of 0 mass% of long chain tri-unsaturated fatty acid residues of carbon atoms 16 to 24, R ² is 1 to 8 carbon atoms
Represents an alkyl group. )

In the above R ¹ CO, the fatty acid residue having 12 to 24 carbon atoms has 12 to 12 carbon atoms.
Examples include 24 long-chain saturated fatty acid residues, long-chain mono-, long-chain di-, or long-chain tri-unsaturated fatty acid residues having 12 to 24 carbon atoms. From the viewpoint of water absorption prevention and shrinkage reduction, the above R ¹
More preferably, CO is a long-chain saturated fatty acid residue having 16 to 24 carbon atoms and a long-chain mono-, long-chain di-, or long-chain triunsaturated fatty acid having 16 to 24 carbon atoms in the total fatty acid residues. It is preferable to contain many residues.
Examples of long-chain saturated fatty acid residues having 12 to 24 carbon atoms include fatty acid residues derived from lauric acid, myristic acid, pentasilic acid, palmitic acid, margaric acid, octadecanoic acid, nonadecanoic acid, arachidic acid, behenic acid and lignoceric acid Groups.
Examples of long-chain monounsaturated fatty acid residues having 12 to 24 carbon atoms include fatty acid residues derived from myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, gadoleic acid, eicosenoic acid, erucic acid, nervonic acid, etc. Groups.
Examples of the long-chain diunsaturated fatty acid residue having 12 to 24 carbon atoms include fatty acid residues derived from linoleic acid, eicosadienoic acid, docosadienoic acid, and the like. Examples of the long-chain triunsaturated fatty acid residue having 12 to 24 carbon atoms include fatty acid residues derived from linolenic acid, pinolenic acid, eleostearic acid, mead acid, dihomo-γ-linolenic acid, eicosatrienoic acid, and the like. Can be mentioned.

In particular, the R ¹ CO is more preferably the proportion of long-chain monounsaturated fatty acid residues having less than 10% by mass of long-chain saturated fatty acid residues having 18 carbon atoms and 18 carbon atoms in the total fatty acid residues. The proportion is preferably 30 to 50% by mass, and the proportion of long-chain diunsaturated fatty acid residues having 18 carbon atoms is preferably 20 to 40% by mass.

In the above R ² , the alkyl group having 1 to 8 carbon atoms includes a methyl group, an ethyl group, n
A linear alkyl group which is a -propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-nonyl group or n-octyl group; isopropyl group, isobutyl group, sec-butyl group, tert-butyl group , Branched chain alkyl groups such as neopentyl group, 1-ethylpropyl group and 2-ethylhexyl group.
Among them, methyl group, n-butyl group, isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, n-octyl group and 2-ethylhexyl group are preferable, and isobutyl group, sec-butyl group and tert-butyl group are preferable. Most preferred.

<(B) Alkoxysilane Derivative>
In the present invention, the (B) alkoxysilane derivative used in the curing agent for concrete reacts an alkoxysilane, a hydrolyzate thereof or a polycondensate thereof with a polyoxyalkylene compound represented by the following general formula (2). Can be obtained.
R ³ O— (AO) _n —H (2)
(In the formula, R ³ represents a hydrocarbon group having 1 to 18 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents an integer of 1 to 20).

Examples of the alkoxysilane include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, and tetrabutoxysilane; methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyl Trialkoxysilanes such as tributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane; dimethyldimethoxysilane, dimethyldi Dialkoxysilanes such as ethoxysilane, diethyldimethoxysilane, and diethyldiethoxysilane can be used. Of these, the use of tetramethoxysilane and tetraethoxysilane is particularly preferred in the present invention from the viewpoints of availability, handling, and the like.

  The alkoxysilane hydrolyzate / polycondensate is prepared, for example, by dissolving a predetermined amount of alkoxysilane in water, water such as methanol, ethanol, ethyl acetate or an organic solvent, and heating or adding a predetermined amount of acid or base. And can be prepared by partial hydrolysis. Usually, the degree of polymerization is preferably 2 to 10.

In the polyoxyalkylene compound represented by the general formula (2), R ³ represents a hydrocarbon group having 1 to 18 carbon atoms, and the hydrocarbon group is an alkyl group having 1 to 30 carbon atoms; An aromatic group having 6 to 18 carbon atoms having a benzene ring such as a group, an alkylphenyl group, a phenyl group substituted with an alkylphenyl group, and a naphthyl group; and 2 to 18 carbon atoms such as an oleyl group and a linoleyl group Among them, an alkenyl group is preferably an alkyl group having 1 to 30 carbon atoms.
Specific examples of the alkyl group having 1 to 30 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, and n-decyl group. Group, n-dodecyl group, n-tetradecyl group, n-hexadecyl group, n-octadecyl group and other linear alkyl groups; isopropyl group, sec-butyl group, tert-butyl group, neopentyl group, 1-ethylpropyl group, Examples thereof include branched alkyl groups such as 1-heptyldecyl group and 2-ethylhexyl group. Among these, an alkyl group having 1 to 8 carbon atoms is preferable, an n-butyl group and a 2-ethylhexyl group are more preferable, and an n-butyl group is most preferable.

In the polyoxyalkylene compound represented by the general formula (2), AO represents an oxyalkylene group having 2 to 4 carbon atoms, and specific examples include an ethyleneoxy group, a propyleneoxy group, and a butyleneoxy group. n is the number of added moles of alkylene oxide, and represents an integer of 0 to 20. When n is 2 or more, the oxyalkylene groups may be the same or different. (AO) When _n is composed of two or more types of alkyleneoxy groups, either block addition or random addition may be used, but block addition is preferred, and the terminal connected to the hydrogen atom is particularly ethylene. More preferred is an oxy group.

  Specific examples of the polyoxyalkylene compound represented by the general formula (2) 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. Examples thereof include polyoxyalkylene alkyl ethers such as monopropyl ether, polyethylene glycol monopropyl ether, polyethylene glycol polypropylene glycol monobutyl ether, and polyethylene glycol monobutyl ether.

The alkoxysilane derivative is prepared, for example, by charging the alkoxysilane, its hydrolyzate or its polycondensate, and the polyoxyalkylene compound represented by the above general formula (2) into a reaction vessel, and heating it to stop the alcohol produced. It can be obtained by conducting a transesterification reaction while leaving. The reaction temperature is usually about 50 to 150 ° C. In the transesterification reaction, a conventionally known catalyst can be used for promoting the reaction. The reaction ratio of the alkoxysilane, its hydrolyzate or its polycondensate and the polyoxyalkylene compound represented by the above general formula (2) is the same as that of the alkoxysilane, its hydrolyzate or its polycondensate. The polyoxyalkylene compound represented by the general formula (2) is preferably 0.3 to 1 equivalent, more preferably 0.5 to 1 equivalent per 1 equivalent of the group.

  In the concrete curing agent used in the present invention, the blending ratio of (A) fatty acid ester mixture and (B) alkoxysilane derivative can be used within a range of 5 to 95:95 to 5 by mass ratio, more preferably 20 ~ 95: 80-5, 50-95: 50-5, 70-95: 30-5, most preferably 70-90: 30-10.

  The concrete curing agent used in the present invention may contain other components generally used in hydraulic compositions in addition to the (A) fatty acid ester mixture and (B) alkoxysilane derivative. Other components that may be included include water-proofing agents, water-resistant agents, water-repellent agents, antifoaming agents, curing agents, and shrinkage reducing agents that are used for general purposes. The compounding ratio of these other components used in combination is, in mass ratio, the total mass of the (A) fatty acid ester mixture and (B) alkoxysilane derivative: the total mass of other components used in combination = 50: 50 to 99: 1. The ratio is preferably 70:30 to 99: 1.

[Cemented hardened body and cement mortar or concrete curing method]
In the present invention, the cement-based cured body is a cement cured mortar in which fine aggregates and water are mixed with cement or further mixed with coarse aggregate, and one or more selected from various admixtures. May be further blended.
The cement used in the present invention is not particularly limited as long as it has hydraulic properties, for example, portland cement such as ordinary portland cement and early-strength portland cement, eco-cement, mixed cement such as blast furnace cement and fly ash cement, and alumina. Latent hydraulic properties such as cement, "super jet cement" (trade name) manufactured by Taiheiyo Cement Co., Ltd. and super fast cement such as "jet cement" (trade name) manufactured by Sumitomo Osaka Cement Co., Ltd., hemihydrate gypsum, blast furnace slag, etc. A substance is mentioned and 1 type, or 2 or more types chosen from these can be used.

By applying the above-mentioned curing agent for concrete on the surface of a hardened cement-based cured body (cement mortar or concrete cured body), the curing agent is impregnated on the surface layer from the surface of the cured body, and the cement-based cured body of the present invention Can be obtained. Specifically, the above-mentioned curing agent for concrete is applied to the hardened body as a finishing aid when finishing the hardened cementitious body, or after hardening and demolding of the hardened cementitious body. The method for applying the curing agent for concrete is not particularly limited as long as it can be applied to the surface of the cement-based cured body, and can be performed by spraying, coating, spraying, spraying, and the like. Those that can be applied uniformly to the surface of the hardened cementitious body are preferred, such as application with a brush or brush, spraying with a sprayer, or the like.
When the concrete curing agent is applied to a cement-based cured body, usually about 50 to 300 g / m ² is used with respect to the surface. If the amount is less than 50 g, there is a concern that it will be difficult to obtain smooth scouring and moisture dissipation prevention effects at the time of finishing, and if it exceeds 300 g, there is a concern that the adhesion strength will be reduced by an excessive amount. Moreover, both mortar and concrete are included as a cementitious hardened | cured material used as object.

The cement-based cured body of the present invention is a cured body in which drying is suppressed in the initial stage of curing, strength development is promoted, and shrinkage is reduced, and drying is suppressed over a long period of time and waterproofness is maintained. It can be. And, by applying the cement mortar or concrete curing method of the present invention, at the initial stage of application, the drying of the cured body is suppressed, the strength development is promoted and the shrinkage is also reduced, and the drying of the cured body is suppressed over a long period of time. It becomes possible to maintain waterproofness.
The reason why the above-mentioned effects (high strength, shrinkage reduction and improvement in water absorption prevention) are obtained is not clear, but a fatty acid ester having a different number of unsaturated bonds is used in combination with a curing agent as a form of a fatty acid ester mixture. Thus, it is presumed that when arranged on the surface of the cured body, each intermolecular steric repulsion is relaxed and a dense layer is formed. It is presumed that this contributes to a high curing effect and water absorption prevention, and also contributes to the suppression of intrusion of carbon dioxide and chloride ions.
Further, the alkoxysilane derivative has a structure in which the balance between hydrophilicity and hydrophobicity is optimized, and has a structure suitable for penetrating into the surface layer portion from the cement-based cured body surface to the inside of several centimeters. Therefore, the derivative contributes to moisture retention in the surface layer portion of the cured body, and is coupled with the prevention of moisture penetration from the outside and the realization of a high curing effect possessed by the above-mentioned fatty acid ester mixture, and drying suppression and waterproofness of the cement-based cured body It is presumed that this will lead to the development of a synergistic effect in the maintenance of carbon dioxide and further the suppression of infiltration of carbon dioxide and chloride ions.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

[Curing agent for concrete]
<Fatty acid ester mixture>
Table 1 shows the composition of the fatty acid ester mixture represented by the formula (1) R ¹ CO—O—R ² used in the following Examples and Comparative Examples.

[Alkoxysilane derivatives]
The alkoxysilane derivative used in the following examples was prepared by the following procedure. In the text, the molar ratio of the polyoxyalkylene compound (hereinafter also referred to as polyalkylene glycol) to the alkoxysilane is the charged molar ratio of the polyoxyalkylene compound to 1 mole of the alkoxy group in the alkoxysilane structure.

(Production Example 1: Production method of alkoxysilane derivative (compound B-1))
In a reaction vessel equipped with a stirrer, thermometer, condenser, distillate collection tank and nitrogen introduction tube, 401 parts of tetraethoxysilane, 1593 parts of polyethylene glycol monobutyl ether (average of polyethylene glycol repeating units is 3) A molar ratio to alkoxysilane: 4) and 5 parts of triethylamine were charged. The reactor was placed in a nitrogen stream, heated to 140 ° C. over 2 hours, stirred at the same temperature for 7 hours, and reacted while distilling the produced ethanol. The end point of the reaction was judged by the amount of ethanol recovered to obtain 1569 parts (yield 95%) of a pale yellow liquid (Compound B-1).

(Production Example 2: Production method of alkoxysilane derivative (compound B-2))
Charge amount, apparatus and production procedure of triethylamine are in accordance with Production Example 1, 317 parts of tetraethoxysilane, polyethylene glycol mono-2-ethylhexyl ether instead of polyethylene glycol monobutyl ether (the average of polyethylene glycol repeating units is 3) Using 1601 parts (molar ratio to alkoxysilane: 4), compound B-2 (1560 parts, yield 95%) was obtained.

(Production Example 3: Method for producing alkoxysilane derivative (compound B-3))
The amount of triethylamine charged, the apparatus and the production procedure were the same as in Production Example 1. Instead of tetraethoxysilane, 1087 parts of ethoxysilane polycondensate (average polymerization degree 5), polyethylene glycol monobutyl ether (average of polyethylene glycol repeating units was 3) Compound B-3 (1707 parts, 95% yield) was obtained using 908 parts (something) (molar ratio to alkoxysilane: 3).

  Examples and comparisons shown in Table 3 below using the fatty acid ester mixture: mixture A-1, comparative mixtures C-1 and C-2, and the prepared alkoxysilane derivatives: compounds B-1 to B-3 It applied to the hardening body of the fresh concrete manufactured with the following procedures as an example of a curing agent, and various performances were evaluated. As Comparative Example 1, a cured body (blank) that did not use a curing agent was also evaluated.

[Manufacture of fresh concrete for testing]
The specifications of the concrete were nominal strength 30 MPa, slump: 8 ± 2.5 cm, air amount: 4.5 ± 1.5%. Table 2 shows the composition of the test concrete. The kneading method uses a horizontal biaxial forced kneading mixer with a nominal capacity of 1 m ³ , and the amount of concrete produced in each batch is set to 0. 0.
Make 8m ³ × 1 batch, first put cement and fine aggregate into mixer and knead for 10 seconds, then mix water, admixture and coarse aggregate, mix for 120 seconds, then discharge, Provided.

[Concrete test evaluation using curing agent]
<Compressive strength test of concrete>
A specimen (φ10 cm × 20 cm) for compressive strength test was prepared from the fresh concrete prepared by the above procedure, and a compressive strength test was performed. The specimen was demolded the day after production, and each curing agent shown in Table 3 was uniformly applied (150 g / m ² ) to the entire specimen surface (top, bottom, side),
In-air curing was performed in an environment of temperature 20 ° C. and humidity 60%. The compressive strength test was based on JIS A 1108 (Concrete compressive strength test method), and after applying the modifier, the compressive strength at a material age of 7 days and a material age of 28 days was measured. The results are shown in Table 3.

<Dry weight loss rate, length change rate>
A concrete specimen (10 cm long × 10 cm wide × 40 cm height) for measuring the dry mass reduction rate and the length change rate was produced from the fresh concrete produced by the above procedure, and the dry mass reduction rate was measured. . The specimen was unframed at the age of 3 days, and after applying each curing agent shown in Table 3 (150 g / m ² ) on the upper surface of the concrete specimen prepared immediately after the deframement, the mass of the specimen was measured and dried. It was used as the base point of mass reduction rate. Moreover, the dimension of the specimen was measured by the mold gauge method, and this was used as the reference value for the rate of change in length. Thereafter, the specimen was stored under the conditions of a temperature of 20 ° C. and a humidity of 60%, and the dry mass reduction rate and length change rate at the age of 28 days were calculated using the formulas described below.
Here, the smaller the value of the dry mass reduction rate means that the moisture dissipation in the test sample can be suppressed. Moreover, the value of the length change rate means that the smaller the value of the length change rate of the specimen to which the curing agent is not applied (Comparative Example 1), the more the drying shrinkage of the specimen is suppressed. The results are shown in Table 3.

《Dry weight loss rate》
Dry mass reduction rate (%) = {[mass of specimen after test−mass of specimen before test] / [mass of specimen before test]} × 100
《Length change rate》
Length change rate (10 ⁻⁶ ) = [length of each specimen after test (mm) −length of specimen before test (mm)] / [length of specimen before test (mm)]

<Water absorption prevention performance test>
A test plate (length 1000 mm × width 1,000 mm × thickness 100 mm, see FIG. 1) was prepared from the fresh concrete prepared according to the above procedure, and applied to the measurement of water absorption prevention performance. After applying each curing agent shown in Table 3 to the surface of the test plate (150 g / m ² ), the test plate was left outdoors using a test plate installation frame assembled with a single pipe pipe (see FIG. 2).
At the age of 28 days, a funnel-shaped glass appliance 2 formed by combining two cylinders having different thicknesses at six locations on the surface of the test plate 1 was installed (adhered) using an adhesive 3 (FIG. 1). (See (B)). The diameter 2a of the thick cylindrical portion in contact with the test plate 1 of the glass instrument 2 is 27 mmφ, the length 2c of the thick cylindrical portion is 40 mm, the diameter 2b of the thin cylindrical portion is 12 mmφ, and the length 2d of the thin cylindrical portion is 115 mm. is there. FIG. 1 (A) shows the adhesion points (test points) of glassware: upper A point to C point and lower D to F points. The inside of the installed glassware 2 was filled with ion exchange water, and the opening 2-1 of the glassware 2 was covered and sealed with a paraffin film. For each of the test points A to F, the water absorption of the ion-exchanged water after 48 hours is measured, and each unit of the upper test point (A point to C point) and the lower test point (D point to E point) The average value of water absorption per unit area (1 cm ² ) (unit water absorption) was determined. The results are shown in Table 3.

  It should be noted that the water absorption prevention performance is such that, as the unit water absorption value is smaller, the moisture intrusion into the specimen can be suppressed as compared with the blank test plate (Comparative Example 1) to which no curing agent is applied. Means. Furthermore, the unit water absorption values of the upper part and the lower part that are equal indicate that the predetermined performance is obtained uniformly.

<Permeation suppression performance test for carbon dioxide>
A test specimen (10 × 10 × 20 cm) is prepared from the fresh concrete prepared according to the above procedure in accordance with JIS A 1153 (accelerated neutralization test method for concrete), and the entire test specimen (top, bottom, side) is prepared. Uniformly apply each dense layer forming agent shown in Table 3 (150 g / m ² )
Each specimen was stored under conditions of a temperature of 20 ° C. and a humidity of 60%. After one week of material age, temperature curing 20 ° C, humidity 60%, CO ₂ concentration 5% accelerated curing, in accordance with JIS A 1152 (measurement of the carbonation depth of concrete), 28 days after the specimen The neutralization depth (carbon dioxide permeability) was measured.

<Chlorine ion penetration inhibition performance test>
A test specimen (10 × 10 × 40 cm) was prepared from the fresh concrete prepared according to the above procedure, and each dense layer forming agent shown in Table 3 was uniformly applied to the entire specimen surface (upper surface, bottom surface, side surface) (150 g / m ² ) and each specimen was stored under conditions of a temperature of 20 ° C. and a humidity of 60%. After one week of material age, each test specimen was sprayed with a 5% NaCl aqueous solution at 40 ° C. for 3 days and then dried at 60% humidity for 4 days.
In accordance with 1171 (Testing method for polymer cement mortar), the salt penetration depth after 28 days was measured.

As shown in Table 3, a cement-based cured body to which a curing agent for concrete containing a fatty acid ester mixture (A-1) and an alkoxysilane derivative (B-1 to B-3) is applied (Example 1 to Example). 3) is a hardened blank (Comparative Example 1) that does not use a curing agent, and a fatty acid ester mixture (C-1) and a long-chain diunsaturated fatty acid residue having a large proportion of long-chain monounsaturated fatty acid residues. Compared with the hardened material (Comparative Example 2 and Comparative Example 3) to which the curing agent containing the fatty acid ester mixture (C-2) containing a large proportion is applied, the compression strength is high, and the dry mass reduction rate and the length change rate are low. As a result, the unit water absorption value indicating the water absorption preventing property was also small. In particular, in the cured bodies of Comparative Example 2 and Comparative Example 3, although the difference between the upper and lower values of the unit water absorption is large, the cured bodies of Examples 1 to 3 are almost different in the upper and lower values of the unit water absorption. As a result, the cured product of the present invention was determined to be a cured product having a predetermined performance uniformly obtained regardless of the place (location) applied.
Furthermore, the hardened bodies (Examples 1 to 3) to which the above concrete curing material was applied were all suppressed in the permeability (diffusibility) of carbon dioxide and chloride ions as compared with the hardened bodies of the comparative examples. The result was assumed to be.
The compressive strength of Examples 1 to 3 is 9 to 10% higher than that of Comparative Example 1. This is because the hardened cement of Examples 1 to 3 is the cement of Comparative Example 1. This suggests that the inside of the surface of the cured body has a dense structure compared to the cured body, and this seems to have led to the suppression of the permeability (diffusibility) of carbon dioxide and chloride ions.

DESCRIPTION OF SYMBOLS 1 ... Test plate 2 ... Glass instrument 2-1 ... Opening part 3 ... Adhesive

Claims (4)

Reacting a fatty acid ester mixture (A) represented by the following general formula (1), an alkoxysilane, its hydrolyzate or its polycondensate, and a polyoxyalkylene compound represented by the following general formula (2) A cement-based cured product obtained by impregnating a surface curing layer from the surface with a curing agent for concrete containing the alkoxysilane derivative (B) obtained by the above.
R ¹ CO—O—R ² (1)
(In the formula, R ¹ CO represents a fatty acid residue having 12 to 24 carbon atoms, and the proportion of long-chain saturated fatty acid residues having 16 to 24 carbon atoms in the total fatty acid residues is 3 to 40% by mass, The proportion of long-chain monounsaturated fatty acid residues having 16 to 24 carbon atoms is 30 to 50% by mass, the proportion of long-chain diunsaturated fatty acid residues having 16 to 24 carbon atoms is 20 to 40% by mass, and a percentage ratio of 0 mass% of long chain tri-unsaturated fatty acid residues of carbon atoms 16 to 24, R ² is 1 to 8 carbon atoms
Represents an alkyl group. )
R ³ O— (AO) _n —H (2)
(In the formula, R ³ represents a hydrocarbon group having 1 to 18 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents an integer of 1 to 20). In the fatty acid ester mixture (A) represented by the general formula (1), R ¹ CO has a ratio of long-chain saturated fatty acid residues having 18 carbon atoms in the total fatty acid residues of less than 10% by mass, carbon The proportion of long-chain monounsaturated fatty acid residues having 18 atoms is 30 to 50% by mass, and the proportion of long-chain diunsaturated fatty acid residues having 18 carbon atoms is 20 to 40% by mass. Cement-based hardened body. Reacting a fatty acid ester mixture (A) represented by the following general formula (1), an alkoxysilane, its hydrolyzate or its polycondensate, and a polyoxyalkylene compound represented by the following general formula (2) A curing method for cement mortar or concrete, comprising applying a curing agent for concrete containing the alkoxysilane derivative (B) obtained by the method to the cement-based cured body surface.
R ¹ CO—O—R ² (1)
(In the formula, R ¹ CO represents a fatty acid residue having 12 to 24 carbon atoms, and the proportion of long-chain saturated fatty acid residues having 16 to 24 carbon atoms in the total fatty acid residues is 3 to 40% by mass, The proportion of long-chain monounsaturated fatty acid residues having 16 to 24 carbon atoms is 30 to 50% by mass, the proportion of long-chain diunsaturated fatty acid residues having 16 to 24 carbon atoms is 20 to 40% by mass, and a percentage ratio of 0 mass% of long chain tri-unsaturated fatty acid residues of carbon atoms 16 to 24, R ² is 1 to 8 carbon atoms
Represents an alkyl group. )
R ³ O— (AO) _n —H (2)
(In the formula, R ³ represents a hydrocarbon group having 1 to 18 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents an integer of 1 to 20). In the fatty acid ester mixture (A) represented by the general formula (1), R ¹ CO has a ratio of long-chain saturated fatty acid residues having 18 carbon atoms in the total fatty acid residues of less than 10% by mass, carbon The proportion of long-chain monounsaturated fatty acid residues having 18 atoms is 30 to 50% by mass, and the proportion of long-chain diunsaturated fatty acid residues having 18 carbon atoms is 20 to 40% by mass. Cement mortar or concrete curing method.

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