JPH07165452A - Carbon fiber reinforced hydraulic composite material - Google Patents

Abstract

PURPOSE:To obtain a carbon fiber-reinforced hydraulic composite material having high specific flexural strength. CONSTITUTION:This hydraulic composite material is produced by mixing and dispersing carbon fibers in a hydraulic raw material. Concretely, carbon fibers having a tensile strength of >=500kg/mm<2> are compounded in an amount to get the total strength of the carbon fibers in 1cm<3> of the composite material of 150-650kg and obtain a cured composite material having a specific bending strength of >=100kg/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon fiber reinforced hydraulic composite material excellent in strength development, which is mainly used in the field of civil engineering and construction.

[0002]

2. Description of the Related Art A carbon fiber reinforced hydraulic composite material was developed to make up for the lack of strength of ordinary mortar by utilizing the tensile strength and elastic modulus of carbon fiber. And excellent toughness. JP 63-1
No. 62559 discloses that carbon fibers having a tensile strength of 100 kg / mm ² or more are used as the carbon fibers for the carbon fiber reinforced hydraulic composite material, which are bundled with a water-soluble polymer of 0.1 to 20% and kneaded during kneading. Disclosed is a method of dispersing carbon fibers in a single yarn.

However, the tensile strength is 100 kg / m.
Even if it is said to be m ² or more, it is 200 k as in the embodiment of the publication.
When it is about g / mm ^2, there is a problem that the fiber is often damaged by cutting during kneading and the flexural strength of the cured carbon fiber reinforced hydraulic composite material is deteriorated. Further, if the amount of the carbon fiber sizing agent attached is too small, the sizing of the carbon fibers becomes weak, and monofilament dispersion occurs during dry kneading. As a result, fluffing occurs or dispersion becomes poor, so that the flexural strength of the carbon fiber reinforced hydraulic composite material is poorly expressed.

On the other hand, if the amount of the sizing agent attached is too large, the sizing of the carbon fibers is too strong, so that the single yarn dispersion does not occur not only during the empty kneading but also after the addition of water. As a result, the reinforcing effect of the carbon fibers is lost, and the bending strength of the carbon fiber reinforced hydraulic composite material is almost the same as the bending strength of ordinary mortar without fibers.

[0005]

DISCLOSURE OF THE INVENTION As a result of various studies to solve the above-mentioned problems, the present inventors have found that carbon fibers having a large tensile strength are the total carbon fibers contained in 1 cm ^{3 of the} hydraulic composite material. A carbon fiber reinforced hydraulic composite material having a bending specific strength after curing of the carbon fiber reinforced hydraulic composite material of 100 kg / cm ² or more is produced by mixing so as to have a strength of 150 to 650 kg. The present invention has been completed and the present invention has been completed. Further, it has been found that there is a preferable amount of the preferable sizing agent.

[0006]

That is, according to the present invention, when carbon fibers having a tensile strength of 500 kg / mm ² or more are mixed into a hydraulic composite material, the chopped strand carbon fibers are dispersed in a single yarn. A sizing agent that makes it possible to
Preferably, the epoxy emulsion sizing agent containing no curing agent is added in an amount of 0.2 to 2% by weight, preferably 0.5 to 1.5% by weight.
We examined the method of adding what was impregnated and made into a chopped strand state to the hydraulic composite material, and calculated by multiplying the number of carbon fibers contained in the unit volume of the carbon fiber reinforced hydraulic composite material by the strength of the carbon fiber It was found that the total strength of the carbon fiber produced is greatly related to the reinforcing effect. That is, the present invention relates to the hydraulic composite material 1c.
The total strength of the carbon fibers contained in m ³ is 150 to 6
A gist of the carbon fiber reinforced hydraulic composite material is 50 kg, and the bending specific strength after hardening of the hydraulic composite material is 100 kg / cm ² or more. The bending specific strength referred to here is a value obtained by dividing the bending strength of the test body by its specific gravity.

The present invention will be described in detail below. First, the raw material of the hydraulic composite material in the present invention, as a matrix may be any of ordinary Portland cement, early strength Portland cement, blast furnace cement, alumina cement and low shrinkage cement, preferably low shrinkage cement and early strength Portland cement. To use.

The carbon fiber used in the present invention is not particularly limited as long as it has a tensile strength of 500 kg / mm ² or more. For example, coal tar pitch, petroleum pitch, coal liquefaction, polyacrylonitrile, cellulose and the like. It is possible to use carbon fibers made from. The diameter of the carbon fiber is 4 to 10 μm, preferably 5 to 8
The one with μm is used. As the fiber length of carbon fiber,
An aspect ratio of 1000 to 4000 is used. When the aspect ratio of the carbon fiber is less than 1000, even if the total strength of the carbon fiber is 150 or more, the strength of the cured product is likely to decrease because the pull-out resistance is small. When it is more than 4000, the kneading is difficult, resulting in poor dispersion of the fibers, the fluidity is lowered, and the strength of the cured product is apt to be lowered.

The fiber sizing agent, when made into a mortar,
A sizing agent that allows the chopped strand-shaped carbon fibers to be dispersed in a single yarn is used. For example, an epoxy emulsion without a curing agent added, or a polyvinyl alcohol-based non-saponified polyvinyl acetate, partially saponified polyvinyl alcohol. , Fully saponified polyvinyl alcohol. Further, cellulose derivatives such as methyl cellulose, ethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose and starch derivatives such as soluble starch are also used. An epoxy emulsion without a curing agent is preferably used. As the epoxy emulsion used in the present invention, the following epoxy compounds emulsified with a surfactant can be used. Examples of the epoxy compound include bisphenol-type, novolak-type, alicyclic-type, resol-type, amino-type, and other epoxy compound monomers and low-polymerization products. Among them, bisphenol A-type having a molecular weight of 470 or less, or novolak An epoxy compound having a type and a molecular weight of 600 or less is preferable. For example, "Epicote" 815, 8 manufactured by Shell Chemical Co.
27, 828 and 834, "Araldite" ECN-1235 manufactured by CIBA-GEIGY (Ciba-Geigy).
Etc. can be illustrated.

Surfactants for emulsifying these include polyoxymethylene castor oil ether, nonyl phenyl ether, polyoxyethylene alkyl ethers such as styrenated phenyl ether, polyoxyethylene alkyl allyl ether and polyvinyl alcohol. At least one surfactant selected from

The amount of the sizing agent attached is 0.2 to 2.0 wt%,
It is preferably adjusted to 0.5 to 1.5 wt%. As the method of impregnation, a sizing agent is mixed in water to a prescribed concentration, and the solution is impregnated with carbon fibers as long fibers through pulleys. The carbon fiber after impregnation is dried and cut at 100 to 120 ° C. The fiber length is preferably 5 to 20 mm. In the case of an emulsion type epoxy, if the amount of impregnation is 0.1 wt% or less, there is almost no difference from the case of no impregnation, and it is difficult to sufficiently disperse the fibers with a normal mortar mixer,
A special mixer like an omni mixer is needed,
The fluffing of the fibers is noticeable even when used. 2-5 wt
In the case of%, since the epoxy emulsion around the carbon fiber is too much and the bond between the carbon fiber and the matrix is weakened, the strength of CFRC is decreased. Further, when the content is 5 wt% or more, the carbon fiber remains in a strand state even after water is added during kneading and single yarn dispersion does not occur, so that the reinforcing effect by the fiber becomes extremely small. In the case of an epoxy emulsion, 0.2-2 wt% is preferable.

The length, strength and addition amount of carbon fiber are determined as follows. The total strength of the carbon fibers obtained by multiplying the number of carbon fibers contained in a unit volume (1 cm ³ ) of the carbon fiber reinforced hydraulic composite material by the strength of the carbon fibers greatly contributes to the reinforcing effect. If the total strength of this carbon fiber exceeds 650 kg, it is difficult to knead and the dispersion of the fiber becomes poor, and the strength of the hydraulic composite material decreases. On the other hand, if it is less than 150 kg, the strength of the hydraulic composite material is lowered because the carbon fibers are easily cut during the kneading, the dispersion is difficult, and the orientation is easily affected. At the same time, if the tensile strength of the fiber is less than 500 kg / mm ³ , if the total strength is increased, the amount of the fiber added is increased, resulting in poor dispersion, and the strength of the hydraulic composite material decreases. In this way, the yarn diameter, the strength, and the addition amount are determined so that the total strength of the carbon fibers contained in the unit volume (1 cm ³ ) of the carbon fiber reinforced hydraulic composite material is 150 to 650 kg / cm ² .

As the aggregate, sand, silica stone, gravel, crushed stone,
Examples include shirasu balloon and fly ash. Preferably, silica sand No. 5 having an average particle size of 6 mm and hollow silica having an average particle size of 40 μm are used as the lightweight aggregate, and a total of 20 to 30 parts are mixed with 100 parts of cement. Further, as the fiber dispersant, those generally used can be used, for example, methyl cellulose, cellulose derivatives such as hydroxyethyl cellulose, polyamide type, polyamine type,
Alkyl picolinium salt type, alkyl amine water-soluble acid type cationic surfactant, alkyl amine oxide type nonionic surfactant, alkyl alanine type, alkyl amine oxide type nonionic surfactant, alkyl glycine type, alkyl alanine Type, alkyl betaine type, alkyl imidazoline type and other amphoteric surfactants, or a mixture of two or more thereof is used.

As the water-reducing agent, a special surfactant containing a triazine ring-based highly condensate salt as a main component, a special polymer having a special sulfone group and a carboxyl group, an anionic special polymer surfactant, a naphthalenesulfonic acid condensate ligninsulfonic acid derivative Etc. The addition amount is 1 to 4 parts with respect to 100 parts of cement. Further, in addition to the dispersant and the water reducing agent, an admixture such as an antifoaming agent and a foaming agent can be appropriately added. As a mixer for kneading the cement raw material, carbon fiber, water and other auxiliaries, all commonly used mixers can be used, including paddle type, propeller type, paddle type, turbine type, pan type, ribbon type, screw type In the case of a mixer having a stirring blade such as a warner type or a kneader type, the carbon fiber and the hydraulic composite material raw material are first mixed without adding water, and then water is added and kneaded.

The carbon fiber reinforced hydraulic composite material of the present invention thus obtained has a flexural specific strength (flexural strength / specific gravity) after curing.
Has an excellent strength of 100 kg / cm ² or more.

[0016]

The present invention will be described in more detail with reference to the following examples. Example 1 In an emulsion solution of 60 parts by weight of an epoxy compound "Epicoat" 834 (manufactured by Shell Chemical Co., Ltd.) and 40 parts by weight of "Epicoat" 1004 (manufactured by Shell Chemical Co., Ltd.), a carbon fiber having a tensile strength of 640 kg / mm < ² > was pulleyd. Impregnated by passing the long fiber as it is, and the impregnation amount is 1.0 wt%
12m after drying at 120 ℃ for 30 minutes
Cut into m chopped strands. This carbon short fiber was put into a mortar mixer with an internal volume of 5 liters so that the total strength of the carbon fibers contained in 1 cm ^{3 of the} hydraulic composite material was 390 kg. .5 parts by weight, lightweight aggregate 1
2.5 parts by weight and 0.25 parts by weight of methyl cellulose were added and dry mixed for 30 seconds to obtain a mixture in which short fibers were sufficiently dispersed. Then, 50 parts by weight of water was added and kneaded for 30 seconds, and then 4
A carbon fiber reinforced hydraulic composite material was produced by casting in a 4 × 16 cm frame. The next day, the mold is removed and the temperature is 20 ° C
R. A bending test was performed after curing for 4 weeks in the T% state. The loading speed was 2 mm / min and the logarithm of the test was n = 6.

Example 2 The epoxy emulsion solution of Example 1 had a tensile strength of 64.
0 kg / mm ² of carbon fiber is passed through the long fiber as it is by using a pulley to be impregnated, the amount of impregnation is adjusted to 1.0 wt%, dried at 120 ° C. for 30 minutes, and then cut into 12 mm chopped strands. . Using this short carbon fiber, Example 1 was prepared so that the total strength of the carbon fiber contained in 1 cm ^{3 of the} hydraulic composite material obtained would be 450 kg.
A carbon fiber reinforced hydraulic composite material was manufactured by the same method as described above, and a bending test was performed.

Example 3 The epoxy emulsion solution of Example 1 had a tensile strength of 64.
0 kg / mm ² of carbon fiber is passed through the long fiber as it is by using a pulley to be impregnated, the amount of impregnation is adjusted to 1.0 wt%, dried at 120 ° C. for 30 minutes, and then cut into 12 mm chopped strands. . Using this short carbon fiber, Example 1 was prepared so that the total strength of the carbon fiber contained in 1 cm ^{3 of the} hydraulic composite material obtained would be 530 kg.
A carbon fiber reinforced hydraulic composite material was manufactured by the same method as described above, and a bending test was performed.

Example 4 The epoxy emulsion solution of Example 1 had a tensile strength of 64.
0 kg / mm ² of carbon fiber is passed through the long fiber as it is by using a pulley to be impregnated, the amount of impregnation is adjusted to 1.0 wt%, dried at 120 ° C. for 30 minutes, and then cut into 12 mm chopped strands. . Using this short carbon fiber, Example 1 was prepared so that the total strength of the carbon fiber contained in 1 cm ^{3 of the} hydraulic composite material obtained would be 160 kg.
A carbon fiber reinforced hydraulic composite material was manufactured by the same method as described above, and a bending test was performed.

Example 5 The epoxy emulsion solution of Example 1 had a tensile strength of 51.
0 kg / mm ² of carbon fiber is passed through the long fiber as it is by using a pulley to be impregnated, the amount of impregnation is adjusted to 1.0 wt%, dried at 120 ° C. for 30 minutes, and then cut into 12 mm chopped strands. . Using this short carbon fiber, Example 1 was prepared so that the total strength of the carbon fiber contained in 1 cm ^{3 of the} hydraulic composite material obtained would be 360 kg.
A carbon fiber reinforced hydraulic composite material was manufactured by the same method as described above, and a bending test was performed.

Example 6 The epoxy emulsion solution of Example 1 had a tensile strength of 64.
0 kg / mm ² of carbon fiber is impregnated by passing it through the long fiber as it is using a pulley, and the impregnation amount is adjusted to 1.5 wt%. After drying at 120 ° C. for 30 minutes, it is cut into 12 mm chopped strands. . Using this short carbon fiber, Example 1 was prepared so that the total strength of the carbon fiber contained in 1 cm ^{3 of the} hydraulic composite material obtained would be 390 kg.
A carbon fiber reinforced hydraulic composite material was manufactured by the same method as described above, and a bending test was performed.

Example 7 The epoxy emulsion solution of Example 1 had a tensile strength of 64.
0 kg / mm ² of carbon fiber is passed through the long fiber as it is by using a pulley to be impregnated, the amount of impregnation is adjusted to 1.0 wt%, dried at 120 ° C. for 30 minutes, and then cut into 12 mm chopped strands. . Using this short carbon fiber, 100 parts by weight of low-shrinkage cement, 20 parts by weight of silica sand, 5 parts by weight of lightweight aggregate, so that the total strength of the carbon fiber contained in 1 cm ^{3 of the} hydraulic composite material obtained will be 390 kg. A carbon fiber reinforced hydraulic composite material was produced in the same manner as in Example 1 together with 0.25 part by weight of methyl cellulose, and a bending test was performed.

Example 8 The epoxy emulsion solution of Example 1 had a tensile strength of 64.
0 kg / mm ² of carbon fiber is passed through the long fiber as it is by using a pulley to be impregnated, the amount of impregnation is adjusted to 1.0 wt%, dried at 120 ° C. for 30 minutes, and then cut into 12 mm chopped strands. . Using this short carbon fiber, 100 parts by weight of low-shrinkage cement, 5 parts by weight of silica sand, 20 parts by weight of lightweight aggregate, so that the total strength of the carbon fiber contained in 1 cm ^{3 of the} hydraulic composite material obtained will be 390 kg. A carbon fiber reinforced hydraulic composite material was produced in the same manner as in Example 1 together with 0.25 part by weight of methyl cellulose, and a bending test was performed.

Comparative Example 1 The epoxy emulsion solution of Example 1 had a tensile strength of 20.
0 kg / mm ² of carbon fiber is impregnated by passing it through the long fiber as it is using a pulley, and the impregnation amount is adjusted to 1.5 wt%. After drying at 120 ° C. for 30 minutes, it is cut into 12 mm chopped strands. . Using this short carbon fiber, Example 1 was prepared so that the total strength of the carbon fiber contained in 1 cm ^{3 of the} hydraulic composite material obtained would be 200 kg.
A carbon fiber reinforced hydraulic composite material was manufactured by the same method as described above, and a bending test was performed.

Comparative Example 2 The epoxy emulsion solution of Example 1 had a tensile strength of 35.
Carbon fibers of 0 kg / mm ² are impregnated by passing them through the long fibers as they are using a pulley, and the impregnation amount is adjusted to be 1 wt%, and the fibers are dried at 120 ° C. for 30 minutes and then cut into 12 mm chopped strands. Using this short carbon fiber,
A carbon fiber reinforced hydraulic composite material was produced by the same method as in Example 1 so that the total strength of the carbon fibers contained in 1 cm ^{3 of the} obtained hydraulic composite material was 340 kg, and a bending test was conducted.

Comparative Example 3 The epoxy emulsion solution of Example 1 had a tensile strength of 64.
Carbon fibers of 0 kg / mm ² are impregnated by passing them through the long fibers as they are using a pulley, and the impregnation amount is adjusted to be 1 wt%, and the fibers are dried at 120 ° C. for 30 minutes and then cut into 12 mm chopped strands. Using this short carbon fiber,
A carbon fiber reinforced hydraulic composite material was manufactured in the same manner as in Example 1 so that the total strength of the carbon fibers contained in 1 cm ^{3 of the} obtained hydraulic composite material was 110 kg, and a bending test was performed.

Comparative Example 4 The epoxy emulsion solution of Example 1 had a tensile strength of 64.
Carbon fibers of 0 kg / mm ² are impregnated by passing them through the long fibers as they are using a pulley, and the impregnation amount is adjusted to be 1 wt%, and the fibers are dried at 120 ° C. for 30 minutes and then cut into 12 mm chopped strands. Using this short carbon fiber,
A carbon fiber reinforced hydraulic composite material was produced by the same method as in Example 1 so that the total strength of the carbon fibers contained in 1 cm ^{3 of the} obtained hydraulic composite material was 700 kg, and a bending test was performed.

Comparative Example 5 The epoxy emulsion solution of Example 1 had a tensile strength of 64.
The carbon fiber of 0 kg / mm ² is impregnated by passing it through the long fiber as it is using a pulley, and the impregnation amount is adjusted to be 3 wt%, dried at 120 ° C. for 30 minutes and then cut into 12 mm chopped strands. Using this short carbon fiber,
A carbon fiber reinforced hydraulic composite material was manufactured in the same manner as in Example 1 so that the total strength of the carbon fibers contained in 1 cm ^{3 of the} obtained hydraulic composite material was 390 kg, and a bending test was performed.

Comparative Example 6 A two-component epoxy emulsion having a tensile strength of 640 kg
/ Mm ² of carbon fiber is impregnated by passing the long fiber as it is using a pulley and cut into 12 mm chopped strands. Using this short carbon fiber, a carbon fiber reinforced hydraulic composite material was produced in the same manner as in Example 1 so that the total strength of the carbon fibers contained in 1 cm ^{3 of the} obtained hydraulic composite material was 390 kg, and the bending test was conducted. I went.

The results are shown in Table 1.

[0031]

[Table 1]

[0032]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, the dispersibility in a mortar and the adhesiveness with the matrix are improved by focusing the carbon fibers in an appropriate amount of the epoxy emulsion solution. By making good use of the characteristics of the carbon fiber, it is possible to manufacture a carbon fiber-reinforced hydraulic composite material having high strength and high reliability against bending.

Claims (4)

[Claims] 1. A hydraulic composite material obtained by mixing and dispersing carbon fibers in a hydraulic raw material, which has a tensile strength of 500 k.
The g / mm ² or more carbon fiber, the total strength of the carbon fiber contained in the composite material 1cm ³ 150~650kg
It is mixed so that the bending specific strength after curing is 100
A carbon fiber reinforced hydraulic composite material characterized by being at least kg / cm ² . 2. A chopped strand state is obtained by impregnating the carbon fiber with a sizing agent, which is used in the form of mortar to allow the chopped strand carbon fibers to disperse in a single yarn, in an amount of 0.2 to 2 wt%. The carbon fiber reinforced hydraulic composite material according to claim 1, which is produced by adding the obtained product to a hydraulic material. 3. The fiber diameter of the carbon fiber is 4 to 10 μm,
The aspect ratio is 1000 to 4000.
The described carbon fiber reinforced hydraulic composite material. 4. The carbon fiber reinforced hydraulic composite material according to claim 2, wherein the sizing agent is an epoxy emulsion containing no curing agent.