JP2876508B2 - Method for producing fiber reinforced concrete - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a carbon fiber reinforced concrete having excellent strength characteristics.

[0002]

2. Description of the Related Art Carbon fiber reinforced concrete is attracting attention as a material having features such as heat resistance, fire resistance, water resistance, light weight and excellent strength, and its use and application to construction, civil engineering, and the like have recently been active. Is being done.

[0003] Carbon fibers are inferior in adhesiveness and dispersibility to a matrix as compared with asbestos and glass fibers which have been conventionally used for reinforcing concrete. Various attempts have been made to increase the strength of the concrete. For example, JP
JP-A-108755 discloses attaching cationic styrene-butadiene rubber latex to the surface of carbon fiber.

[0004]

However, in the prior art, the type of target carbon fiber is limited, the form of the target carbon fiber is limited, the construction method is limited,
There are inconveniences such as the target cement type being limited. Carbon fiber that can be used without such restrictions, cement
The advent of a high-strength carbon fiber reinforced concrete with good adhesion and dispersibility to a matrix has been desired.

In view of the above situation, the present inventors have developed a carbon fiber reinforced concrete which is not restricted by the conventional methods, and which has improved adhesion and dispersibility of carbon fibers to a matrix and excellent strength. The present invention has been made for the purpose of manufacturing a method for manufacturing a semiconductor device.

[0006]

According to the present invention, a carbon fiber having an O _ls / C _ls peak ratio of at least 0.10 as measured by the ESCA method is obtained by emulsifying a rubber-like polymer with a cationic surfactant. is ζ potential - carbon fibers treated with 10mV above dispersion, in the manufacturing method of fiber reinforced concrete, characterized in that dispersed in a cementitious matrix.

Hereinafter, the present invention will be described in detail. The carbon fiber used in the present invention, can be used without being limited particularly as long as it is a known carbon fibers, <br/> Me strength of reinforced concrete is Ru main purpose der particularly in the present invention, It is desirable that the carbon fiber as the reinforcing material has higher strength. Therefore, polyacrylonitrile-based carbon fibers that are versatile and easy to obtain high strength characteristics are preferable.

[0008] Further, the carbon fiber usable in the present invention is E
The _Ols / _Cls peak ratio measured by the SCA method is 0.10 or more. Carbon fibers having an O _ls / C _ls peak ratio of 0.10 or more measured by the ESCA method can be obtained by well-known surface oxidation treatment of carbon fibers. In particular, electrolytic oxidation is practical because it has the advantage of oxidizing short fibers one by one in a short time.
O _{ls /} C _ls not be achieved in improving the strength of the fiber reinforced concrete be used after dispersion treatment of silicone rubber fine particles to the carbon fibers of less than the peak ratio of 0.10.

Examples of the cationic surfactant include alkylamines such as polyoxyethylene tallow alkylamine and polyoxyethylene tallow alkylpropylenediamine, lauryltrimethylammonium chloride, lauryldimethylbenzylammonium chloride, and cetyldimethylethylammonium. A quaternary ammonium salt such as bromide or lauryldimethylchlorobenzylammonium chloride is used, and it is preferable that the ζ potential in water becomes −10 mV or more when the dispersion is used. By appropriately selecting the type and concentration of the surfactant, the ζ potential of the silicon rubber fine particles can be controlled.
Can be

[0010] The amount of silicon rubber particles attached to the carbon fibers is preferably in the range of 0.1 to 5% by weight. If the amount is less than 0.1% by weight, the effect is not exhibited. If the amount is more than 5% by weight, the fibers adhere to each other and the dispersion in the cement matrix becomes insufficient.
When carbon fiber reinforced concrete is used, the effect of improving strength characteristics cannot be obtained.

The carbon fiber reinforced concrete of the present invention, which is obtained by using a carbon fiber surface-treated with a dispersion obtained by dispersing a silicone rubber with a cationic surfactant, has a higher strength characteristic than that of the untreated carbon fiber. Is excellent.

It is presumed that this improvement effect is due to the electrostatic properties of the surfactant scattered on the surface of the carbon fiber and the adhesion of the silicone rubber. In other words, the surface treatment with the cationic dispersion liquid repels the carbon fibers and enhances the dispersibility, and the action of the silicone rubber fine particles, which are the main component of the treatment agent, enhances the adhesion to the cement matrix, resulting in reinforcement. It is considered that the strength properties of the concrete were improved.

Further, the carbon fiber reinforced concrete according to the present invention.
The high strength of the carbon fiber indicates that the surface condition of the carbon fiber is greatly related to the type of the treatment agent. That is, when the O _1s / C _1s peak ratio of the carbon fiber measured by the ESCA method is 0.10 or more, cationic The treatment with the dispersing liquid is effective for improving the strength characteristics. At this time, the effect of the treatment with the anionic or nonionic dispersion is small.

In the present invention, the treated carbon fiber is
When used as a reinforcing material, there is no restriction on the fiber form as in the past, and short fibers, long fibers, strands, sheets, nonwovens,
It can be used in various forms such as woven, direct spray
It has the advantage that it can be constructed by various methods, such as a method, a premix method, an impregnation method, and a hand lay-up method. In addition, molded articles having various shapes such as plate, tube, and column can be formed by using various hydraulic cements.

[0015]

Next, the present invention will be described more specifically with reference to examples. Example 7 μm diameter, specific gravity 1.79, tensile strength 350 kgf / m
m ² , elastic modulus 24 × 10 ³ kgf / mm ² , elongation 1.
5% carbon fibers, aqueous solution of phosphoric acid, O _ls obtained by two-step treatment with ammonium bicarbonate <br/> aqueous solution
/ _{C ls} peak ratio is a carbon fiber bundle of 0.13, a polydimethylsiloxane rubber having an average particle diameter of 0.2 [mu] m, it was dispersed in polyoxyethylene beef tallow alkyl amine concentration 1.0
%, Ζ potential −6 mV, and then dried at 120 ° C. for 2 minutes.

This carbon fiber bundle was cut into a length of 3 mm, and a carbon fiber reinforced concrete specimen was prepared with the composition shown in Table 1. The kneading was performed using a 10-liter omni-mixer with a fiber mixing ratio of 1%.

[0017]

[Table 1]

After molding, primary curing (one day in a moisture chamber)
After one day of material release, second curing (7 minutes in water at 30 ° C)
Days). The carbon fiber reinforced concrete was evaluated using a specimen of 4 cm in length, 16 cm in width and 4 cm in thickness.
A centrally loaded bending test was performed at a span of 10 cm and a crosshead speed of 2 mm / min. Result is 267 Kgf
/ Cm ² .

COMPARATIVE EXAMPLE 1 A carbon fiber reinforced concrete specimen was prepared using carbon fibers treated with a nonionic acrylic / styrene dispersion having a ζ potential of −19 mV and a concentration of 1.0% in the same manner as in the example. It was prepared and subjected to a bending test. The result is 200 kgf / cm ²
Met.

Comparative Example 2 A carbon fiber reinforced concrete specimen was prepared using carbon fibers treated with an anionic silicone rubber dispersion having a ζ potential of -44 mV in the same manner as in the example, and a bending test was conducted. . The result was 186 kgf / cm ² .

Comparative Example 3 A carbon fiber reinforced concrete specimen was prepared using untreated carbon fiber in the same manner as in the example, and a bending test was performed. The result was 220 kgf / cm ² .

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 20:10) 103: 44 (72) Inventor Yoshitaka Imai 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research (72) Inventor Yoshikazu Takei 2-9-1-1, Tobita-Shi, Chofu-shi, Tokyo Kashima Construction Co., Ltd. (72) Inventor Koji Satoyama 2-9-1, Tobita-Ki, Chofu-shi, Tokyo Kashima Construction Co., Ltd. Technical Research Institute (56) References Annual Cement Technology Report, (Showa 61) p. 479 −482 (58) Field surveyed (Int.Cl. ⁶ , DB name) C04B 14/38 C04B 28/02

Claims (1)

(57) [Claims] 1. _Ols / C measured by the ESCA method
_A carbon fiber having an _ls peak ratio of 0.10 or more is obtained by dispersing silicon rubber fine particles with a cationic surfactant.
- carbon fibers treated with 10mV above dispersion method for producing a fiber reinforced concrete, characterized in that dispersed in a cementitious matrix.