JP3274402B2 - Fiber for reinforcing concrete impact strength and concrete molding using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber for reinforcing concrete impact strength having an excellent concrete reinforcing effect. More specifically, a fiber for reinforcing concrete impact strength, which is preferably used for concrete moldings mainly composed of building materials such as construction boards and tiles, and the concrete impact strength thereof
The present invention relates to a concrete molded body formed using a reinforcing fiber.

[0002]

2. Description of the Related Art Hardened cement is widely used in the fields of construction and civil engineering because of its low cost in addition to excellent properties such as compressive strength, durability and nonflammability. However,
Because it is a brittle material, it has extremely low flex resistance,
It easily breaks or cracks when bending stress is applied,
There are drawbacks such as low impact resistance. In recent years, in order to solve these problems, use of various inorganic fibers and organic synthetic fibers as fibers for reinforcing cement has been proposed. However, the properties of the fibers cannot be used effectively, or the fibers have both advantages and disadvantages, and the effects cannot be sufficiently exhibited.
The concrete reinforcement effect has not reached a satisfactory level. For example, olefin fibers have alkali resistance and heat resistance, and can be cured in an autoclave or steam, which is advantageous for concrete reinforcement. However, the surface of the olefin fiber is hydrophobic, has poor adhesion to a hydrophilic cement matrix, and has poor dispersibility in a cement slurry. As a prior art for solving this problem, there is known a technique for improving the affinity for cement by treating the surface of a fiber with a surfactant or the like (Japanese Patent Laid-Open No. 4-21).
556, JP-A-5-170497, PCT International Publication WO
90/06902). Although the fibers described in these prior art documents show a fairly good concrete reinforcing effect, there is a demand for a concrete molded body having further improved bending strength and impact strength. In recent years, in order to improve dispersibility and affinity, and to enhance the reinforcing effect, the cross section of the fiber is deformed, projections or nodes are formed on the fiber surface, or the surface is coated with other components. There have been proposed improvement measures such as improving the fiber strength, kneading other components, and specializing raw materials, but have not yet reached a satisfactory range.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the impact absorption energy, improve the affinity and dispersibility with a cement matrix, and improve the bending strength and compressive strength, particularly impact strength, of a concrete molded product. Concrete opposition
It is an object of the present invention to provide an impact strength reinforcing fiber.

[0004] The present inventors have conducted intensive studies to achieve the above-mentioned object, and as a result, have obtained not only the strength but also the elongation of the polypropylene fiber by making use of the knowledge on the physical properties and the concrete reinforcement of the polypropylene fiber. Maintaining a high level has the effect of improving not only the bending strength but also the impact strength of the concrete molding, and in combination with it, higher fatty acid metal salts, higher alcohol sulfate metal salts,
At least one selected from the group consisting of metal salts of higher alkyl ether sulfates, metal salts of alkyl benzene sulfonic acids, metal salts of alkyl benzene naphthalene sulfonic acids, metal salts of paraffin sulfonic acids, alkyl amine salts, and alkyl ammonium salts; When a surfactant having an alkyl group is attached to the surface of the polypropylene fiber, the impact absorption energy increases, and the affinity and dispersibility with the cement matrix are improved. Since the effect of dramatically improving the impact strength is seen, it is known that such a polypropylene fiber is suitable as a fiber for reinforcing the concrete impact strength , and a concrete molded article formed using the fiber has an extremely excellent impact strength. Finding strength Which resulted in the completion of the Akira.

[0005]

The present invention has the following arrangement to solve the above-mentioned problems. (1) Concrete reinforcing fibers made of polypropylene fibers having a single yarn strength of 5 g / d or more and a single yarn elongation of 40% or more, wherein the fibers include higher fatty acid metal salts, higher alcohol sulfate metal salts, At least one selected from the group consisting of metal salts of higher alkyl ether sulfates, metal salts of alkylbenzene sulfonic acids, metal salts of alkyl benzene naphthalene sulfonic acids, metal salts of paraffin sulfonic acids, alkyl amine salts, and alkyl ammonium salts;
A fiber for reinforcing concrete impact strength , wherein 0.1 to 10% by weight of a surfactant having an alkyl group of from 22 to 22 is attached to the weight of polypropylene fiber. (2) The fiber for reinforcing concrete impact strength according to the above (1), wherein the polypropylene fiber has a single yarn strength of 7 g / d or more and a single yarn elongation of 70% or more. (3) The fiber for reinforcing concrete impact strength according to the above (1) or (2), wherein the metal salt is at least one kind of alkali metal salt selected from Na, Li and K. (4) The concrete according to any one of the above (1) to (3)
Concrete molded body formed by using fiber for impact strength reinforcement.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The polypropylene fiber used for the concrete impact strength reinforcing fiber of the present invention has a single yarn strength of 5 g / d or more and a single yarn elongation of 40% or more. Concrete impact of the present invention
The fiber for strength reinforcement has a single yarn strength of 5 g / d or more, and a higher fatty acid metal salt, a higher alcohol sulfate metal salt, a higher alkyl ether sulfate metal salt, and a polypropylene fiber having a single yarn elongation of 40% or more. A surfactant having at least one alkyl group having 8 to 22 carbon atoms selected from the group consisting of a metal salt of an alkylbenzenesulfonic acid, a metal salt of an alkylbenzenenaphthalenesulfonic acid, a metal salt of a paraffinsulfonic acid, an alkylamine salt, and an alkylammonium salt; Is 0.1 to 10% by weight based on the weight of polypropylene fiber
It is a fiber for reinforcing concrete impact strength attached.

In a further preferred aspect of the present invention,
For the purpose of reinforcing concrete impact strength , the above-mentioned surfactant is attached to a polypropylene fiber having a single yarn strength of 7 g / d or more, and a single yarn elongation of 70% or more, based on the weight of the polypropylene fiber. Fiber. These metal salts of higher fatty acid salts, higher alcohol sulfates, higher alkyl ether sulfates, alkylbenzene sulfonates, alkylbenzene naphthalene sulfonates, and paraffin sulfonates are at least selected from Na, Li, and K. One alkali metal salt is used.
Other salts are represented by primary amine salts, secondary amine salts and tertiary amine salts, and alkylammonium salts such as alkylamine salts and quaternary ammonium salts are used. Further, divalent metal salts such as Ca, Mg and Ba can also be used.

The polypropylene fiber used as the base material of the fiber for reinforcing the concrete impact strength of the present invention may be one in which the raw material polypropylene is made of 100% propylene units, and 2% by weight or less of ethylene units or C4 or more in the polymer. Butene-1, pentene-1,4-methylpentene
A copolymer of a polypropylene containing olefin units such as 1, hexene-1, octene-1, and other olefins may be used. Further, a mixture of a crystal random copolymer or a block copolymer of propylene, ethylene and olefin may be used as the polypropylene resin.

The polypropylene resin according to the present invention includes:
Further, within the range not hindering the effects of the present invention, an antioxidant,
Light stabilizers, ultraviolet absorbers, neutralizers, nucleating agents, epoxy stabilizers, lubricants, antibacterial agents, flame retardants, antistatic agents, pigments, plasticizers, etc. Good.

Next, a method for producing a polypropylene fiber having a single yarn strength of 5 g / d or more and a single yarn elongation of 40% or more as a base material of the fiber for reinforcing concrete impact strength of the present invention will be described. First, spinning is preferably performed at a spinning temperature in the range of 250 to 350 ° C, and more preferably in the range of 310 to 340 ° C, because it is possible to obtain an undrawn yarn with reduced fiber orientation. When the spinning temperature is less than 250 ° C., the fibrous polypropylene melt extruded from the spinneret from the polypropylene melt melted by the extruder is rapidly cooled, and the fiber deformation at the solidification point is large, and the orientation is further advanced. However, it is not preferable because it is an undrawn yarn. In addition, when the spinning temperature exceeds 350 ° C, the decomposition of the polypropylene resin rapidly progresses, and it is difficult not only to obtain an undrawn yarn having good spinnability due to fiber firing, but also the molecular chains of the fiber are severely cut. Even if it is reduced in molecular weight and stretched, it does not become a high-strength polypropylene fiber.

When the extruded fibrous polypropylene melt is cooled, conventional methods such as air, water,
It can be cooled in a medium such as glycerin or the like to a temperature lower than the melting point, and can be drawn. However, in order to suppress the orientation of the undrawn yarn as much as possible, it is preferable to cool with air instead of quenching with liquid. Air temperature and air volume can be set arbitrarily,
In order to obtain an undrawn yarn with further suppressed orientation, it is preferable that the temperature is gradually cooled, that is, the air volume is weak and the temperature is not too low.
Such slow cooling is preferable because a higher-order crystal structure in which the lamellas are arranged at right angles to the fiber axis direction can be sufficiently formed.

[0012] The winding speed of the undrawn yarn is 200 to 1000 m / m so that the deformation at the solidification point of the fibrous polypropylene melt is small and the orientation does not progress.
It is preferably in. More preferably, it is preferable to take off at as low a speed as possible, so as not to be less than 200 m / min. On the other hand, if the take-up speed is 1000 m / min or more, the fibrous polypropylene melt is greatly deformed at the solidification point, becomes an oriented unstretched yarn, has poor stretchability, and cannot be stretched at a high magnification. On the other hand, if it is less than 200 m / min, high-temperature spinning cannot produce a uniform undrawn yarn which is slower than the natural falling speed of the polypropylene melt having a lowered melt viscosity.

The cross-sectional shape of the polypropylene fiber as the base material of the fiber for reinforcing the concrete impact strength can be circular or irregular. In the case of an irregular cross-section, any shape such as a flat shape, a square shape such as a triangular to octagonal shape, a T-shape, a multi-lobe shape, a hollow cross-sectional shape, etc., is not particularly limited.

Next, stretching will be described. The polypropylene undrawn yarn obtained by the above-described method is drawn to obtain a polypropylene fiber having high strength and elongation. A known method such as hot roll drawing, hot water drawing, and a heating plate is employed as a method for drawing the undrawn polypropylene yarn. The stretching operation is one-step stretching, 2
The stretching can be carried out by either step stretching or multi-stage stretching, but it is preferable to carry out a stretching operation of two-stage stretching or more than one-stage stretching. Stretching is performed at a relatively low temperature of 50 to 90 ° C. When drawn at a temperature of 90 ° C. or more, the oriented crystallization of the undrawn yarn proceeds rapidly, and at a temperature lower than 50 ° C., the drawability is reduced and the draw ratio required for high strength cannot be obtained.

The stretching ratio at this time is preferably in the range of 4.2 to 6.0 times. More preferably, it is in the range of 5.0 to 5.8 times.
If it is less than 4.2 times, the single yarn strength is low, and if it exceeds 6.0 times, the single yarn elongation decreases. Next, when performing two-stage drawing, the film is drawn at a draw ratio of 40% or more, preferably 50% or more of the total draw ratio in one-step drawing, and then to a range where single yarn breakage and fluffing do not occur in the second step. It is preferable that the film is stretched and the total stretching ratio is within the above range. Even if the total stretching ratio is the same as the case where the single-stage stretching is performed at a stretching ratio of less than 40% of the total stretching ratio and the single-stage stretching is performed at 40% or more of the total stretching ratio, the high-strength polypropylene is used. Fiber cannot be obtained.
This is because orientation crystallization remarkably progresses in one-step stretching,
In two or more stages of stretching, unreasonable stretching takes place, and as a result, the strength does not increase. Here, the stretching ratio is represented by a ratio between a supply roll speed and a take-up roll speed.

Further, by subjecting the drawn product of the drawn polypropylene fiber to an annealing treatment at a temperature near the melting point by a constant length heat treatment, a relaxation heat treatment or the like, a polypropylene fiber having improved heat shrinkage can be obtained.

Through such spinning and drawing steps, a polypropylene fiber having physical properties of a single yarn strength of 5 g / d or more and a single yarn elongation of 40% or more can be obtained. In particular, spinning at a high temperature of 310 ° C or higher and low-temperature drawing or two-step drawing
A high strength polypropylene fiber with a single yarn strength of 6 g / d or more and a single yarn elongation of 50% or more, which is optimal for impact strength reinforcement, can be obtained.

The surfactant may be attached to the polypropylene fiber in any of the spinning step and the drawing step. The adhesion method is a roller method, a dipping method, a spray method,
A pad dry method or the like can be used. Preferably, the attachment in the spinning step and the drawing step may provide uniform attachment.

The concrete impact strength reinforcing fiber of the present invention is a metal salt of a higher fatty acid having 8 to 22 carbon atoms, a metal salt of a higher alcohol sulfate, a metal salt of a higher alkyl ether sulfate, a metal salt of an alkylbenzenesulfonic acid, an alkylbenzenenaphthalenesulfonic acid. A metal salt, a paraffin sulfonic acid metal salt, an alkylamine salt, or an alkylammonium salt, at least one surfactant selected from the group consisting of an appropriate amount or an amount of 0.1 to 10 wt. %. If it is less than 0.1% by weight, the reinforcing effect cannot be sufficiently obtained, and if it exceeds 10% by weight, the effect becomes saturated and the bending strength, impact strength and impact absorption energy reach equilibrium. Further, since the viscosity of the surface treatment agent is increased, productivity is deteriorated, and it is uneconomical, so that there is no need for practical use.

The fiber for reinforcing concrete impact strength according to the present invention comprises a polypropylene fiber having a single yarn strength of 5 g / d or more and a single yarn elongation of 40% or more, since the above-mentioned surfactant is attached to the fiber. The effect, especially the reinforcing effect on the impact strength is improved.

The impact strength of concrete increases as the impact absorption energy increases. The impact absorption energy is energy from the time when the concrete molded body receives stress until the stress after rupture becomes zero.

When the single yarn elongation of the polypropylene fiber is 40% or more and the single yarn strength is 5 g / d or more, the impact absorption energy is more than the conventional value from the quadratic function of the elongation and the strength.
Impact strength increases. Furthermore, single yarn elongation of the polypropylene fibers is 70% or more, if the single yarn strength is 7 g / d or more, the impact absorbed energy to improve the impact strength for you dramatically improve seen.

That is, by attaching the above-mentioned surfactant to the surface of the polypropylene fiber, the affinity for concrete and the dispersibility are improved. The surfactant is a compound having both polarities of a hydrophilic group and a hydrophobic group. By adhering the surfactant to the surface of the polypropylene fiber, hydrophobic groups have an affinity between the polypropylene fiber and the surfactant and have a binding force, and a hydrophilic group is formed between the surfactant and the cement. The calcium ions in the cement are opposed to each other, and the salt of the surfactant is replaced, and the calcium salt of the surfactant becomes an insoluble and sticky substance, and cement particles are formed on the surface of the fiber for reinforcing the concrete impact strength. Adhere to. That is, by interposing the surfactant between the polypropylene fiber and the cement, the adhesion between the cement and the concrete impact strength reinforcing fiber is strengthened and the affinity is improved, and the concrete impact strength reinforcing fiber is contained in the cement. Uniform dispersion is easy, and dispersibility is also improved.

The reinforcing effect can also be obtained by improving the elongation and strength of the polypropylene fiber or by adhering the surfactant, but a synergistic effect can be obtained by combining the two as in the present invention. In particular, polypropylene fibers having a single yarn strength of 5 g / d or more and a single yarn elongation of 40% or more,
Although it has excellent basic strength physical properties, the synergistic effect of attaching the surfactant in the previous period provides a good balance between the affinity of the polypropylene fiber and the surfactant, and further increases the adsorption power to the fiber surface. The effect of dramatically improving physical properties (particularly impact strength) is seen. This is because the prior art of the present invention is disclosed in Japanese Patent Laid-Open No. 5-170.
497 (especially Examples 8 and 10) have physical properties such as a breaking strength of 5 g / d or more and a breaking elongation of 40% or more. In contrast to 180 to 190 kgf / cm ² and impact strength of 3.4 to 3.7 kgf · cm / cm ² , the concrete molded body using the polypropylene fiber of the present invention has a flexural strength as shown in Examples described later. Is 21
0 kgf / cm ² or more, impact strength is 13 kgf · cm /
It is clear from the fact that it is dramatically improved to not less than cm ² .

[0025]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The bending strength was measured according to JIS-A1408. For measuring the impact strength, a concrete molded body was 10 mm wide, 5 mm thick,
It was cut to a length of 50 mm and performed according to JIS-B-7722 Charpy impact test. The measurement of the impact absorption energy was performed by analyzing the SS curve chart of the bending strength test and calculating from the area thereof.

Example 1 Melt flow rate (hereinafter MFR)
25 polypropylene, temperature 250 ℃, take-off speed 400m / mi
After melt-spinning at n, stretch by 4.6 times at 90 ° C, fiber diameter is about 17μm (about 2d / f), fiber strength is 5.1g / d, fiber elongation is 42.1%
After stretching, potassium oleate as a surface treatment agent was applied in an amount of 0.1% by weight based on the fiber weight by a touch roll and dried, and then cut into 6 mm to obtain a fiber for reinforcing concrete impact strength .

Next, 1000 g of ordinary Portland cement,
Silica sand No.7 1000g, fiber for reinforcing concrete impact strength 4
0 g, 20 g of methylcellulose, and 360 g of water were mixed, kneaded using a kneader, and extruded to obtain a flat concrete molded body having a thickness of 5 mm and a width of 50 mm. The molded body was cured in water for 28 days, and then was cured at 60 ° C. for 24 hours and at 95 ° C. for 8 hours.
After drying for an hour, a concrete molded body was obtained.

Example 2 The adhesion amount of the surface treating agent of Example 1 was
A concrete molded body was obtained in the same manner as in Example 1 except that the content was 9.8% by weight.

Example 3 A concrete molded body was obtained in the same manner as in Example 1 except that the surface treating agent of Example 1 was sodium lauryl ether sulfate and the amount of adhesion was 0.3% by weight.

Example 4 The adhesion amount of the surface treating agent of Example 3 was
A concrete molded body was obtained in the same manner as in Example 3, except that the content was 6.6% by weight.

Example 5 The surface treating agent of Example 1 was changed to sodium dodecylbenzenesulfonate, and the attached amount was 0.6% by weight.
Except having been described, a concrete molded body was obtained in the same manner as in Example 1.

Example 6 The adhesion amount of the surface treating agent of Example 5 was
A concrete molded body was obtained in the same manner as in Example 5, except that the content was 3.2% by weight.

Example 7 The adhesion amount of the surface treating agent of Example 1 was
A concrete compact was obtained in the same manner as in Example 1 except that the content was 1.2% by weight.

Example 8 A concrete molded body was obtained in the same manner as in Example 1 except that the surface treating agent of Example 1 was changed to potassium octylate and the amount of adhesion was 1.3% by weight.

Example 9 A concrete compact was obtained in the same manner as in Example 1 except that the surface treating agent of Example 1 was changed to potassium stearate and the amount of adhesion was 0.9% by weight.

Example 10 A concrete molding was obtained in the same manner as in Example 1 except that the surface treating agent of Example 1 was changed to potassium behenate and the amount of adhesion was 2.5% by weight.

Example 11 A concrete molding was obtained in the same manner as in Example 1 except that the surface treating agent of Example 1 was changed to an amine oleate salt and the amount of adhesion was 1.7% by weight.

Example 12 The procedure of Example 1 was repeated except that the surface treating agent was sodium linoleate and the amount of adhesion was 4.4% by weight.
In the same manner as in Example 1, a concrete molded body was obtained.

Comparative Example 1 The adhesion amount of the surface treating agent of Example 1 was
A concrete molded body was obtained in the same manner as in Example 1 except that the content was 0.05% by weight.

Comparative Example 2 A concrete molded body was obtained in the same manner as in Example 1 except that the surface treating agent of Example 1 was not adhered.

Comparative Example 3 The adhesion amount of the surface treating agent of Example 3 was
A concrete molded body was obtained in the same manner as in Example 3, except that the content was 0.03% by weight.

Comparative Example 4 The adhesion amount of the surface treating agent of Example 5 was
A concrete molded body was obtained in the same manner as in Example 5, except that the content was 0.07% by weight.

The above "Examples 1 to 12" and "Comparative Example 1"
The results of evaluating the physical properties of the concrete molded product of “.
It is shown in Table 1.

[0044]

[Table 1]

As is clear from Table 1, Examples 1 to 12
It can be seen that is excellent in the effect of reinforcing the concrete impact strength .

In Comparative Example 2, the impact strength was particularly poor because there was no surface treatment agent. The effects of the fibers were not sufficiently brought out, and in Comparative Examples 1, 3, and 4, the adhesion amount of the surface treatment agent was less than 0.1% by weight, and the effect of reinforcing the fibers was not sufficiently exhibited.

Example 13 The polypropylene of MFR40 was
After melt spinning at a temperature of 330 ° C and a take-up speed of 300m / min,
A two-stage drawing is performed with a draw ratio of 3.1 times the second stage and 1.8 times the second stage. The fiber diameter is about 17 μm (about 2 d / f), the fiber strength is 7.3 g / d, and the fiber elongation is 72.4%. Then, 1.1% by weight of potassium oleate was adhered as a surface treatment agent, dried, and cut into 6 mm to obtain a fiber for reinforcing concrete impact strength .

Next, 1000 g of ordinary Portland cement,
Silica sand No.7 1000g, fiber for reinforcing concrete impact strength 4
0 g, 20 g of methylcellulose, and 360 g of water were mixed, kneaded using a kneader, and extruded to obtain a flat concrete molded body having a thickness of 5 mm and a width of 50 mm. The molded body was cured in water for 28 days, and then was cured at 60 ° C. for 24 hours and at 95 ° C. for 8 hours.
After drying for an hour, a concrete molded body was obtained.

Example 14 A concrete molding was obtained in the same manner as in Example 13 except that the surface treating agent of Example 13 was changed to potassium stearate and the amount of adhesion was 2.3% by weight.

Comparative Example 5 A polypropylene of MFR25 was melt-spun at a temperature of 230 ° C. and a take-up speed of 500 m / min.
Draw twice and make fiber diameter about 17μm (about 2d / f), fiber strength 4.3g / d, fiber elongation 25.4%. After drawing, attach 1.7% by weight of potassium oleate as a surface treatment agent with a touch roll. After drying, cut to 6mm and impact with concrete
The fiber was used as a reinforcing fiber.

Next, 1000 g of ordinary Portland cement,
Silica sand No.7 1000g, fiber for reinforcing concrete impact strength 4
0 g, 20 g of methylcellulose, and 360 g of water were mixed, kneaded using a kneader, and extruded to obtain a flat concrete molded body having a thickness of 5 mm and a width of 50 mm. The molded body was cured in water for 28 days, and then was cured at 60 ° C. for 24 hours and at 95 ° C. for 8 hours.
After drying for an hour, a concrete molded body was obtained.

Comparative Example 6 A concrete molded body was obtained in the same manner as in Comparative Example 5, except that the surface treating agent of Comparative Example 5 was not adhered.

Comparative Example 7 MFR32 polypropylene was melt-spun at a temperature of 300 ° C. and a take-up speed of 400 m / min.
Draw twice and make the fiber diameter about 17μm (about 2d / f), fiber strength 6.9g / d, fiber elongation 21.2%, and after drawing, attach 1.6% by weight of potassium oleate as surface treatment agent by touch roll After drying, cut to 6mm and impact with concrete
The fiber was used as a reinforcing fiber.

Next, 1000 g of ordinary Portland cement,
Silica sand No.7 1000g, fiber for reinforcing concrete impact strength 4
0 g, 20 g of methylcellulose, and 360 g of water were mixed, kneaded using a kneader, and extruded to obtain a flat concrete molded body having a thickness of 5 mm and a width of 50 mm. The molded body was cured in water for 28 days, and then was cured at 60 ° C. for 24 hours and at 95 ° C. for 8 hours.
After drying for an hour, a concrete molded body was obtained.

Comparative Example 8 A concrete molded body was obtained in the same manner as in Comparative Example 8 except that the surface treating agent of Comparative Example 8 was not adhered.

Comparative Example 9 Polypropylene of MFR28 was melt-spun at a temperature of 250 ° C. and a take-up speed of 350 m / min, and then stretched 3.8 times at 60 ° C. to have a fiber diameter of about 17 μm (about 2 d / f) and a fiber strength of 3.4 g. / d, fiber elongation 72.4%, after stretching 1.3 kg by weight of potassium oleate as a surface treatment agent with a touch roll
After adhering and drying, cut into 6mm and concrete impact strength
The fiber was used as a reinforcing fiber.

Next, 1000 g of ordinary Portland cement,
Silica sand No.7 1000g, fiber for reinforcing concrete impact strength 4
0 g, 20 g of methylcellulose, and 360 g of water were mixed, kneaded using a kneader, and extruded to obtain a flat concrete molded body having a thickness of 5 mm and a width of 50 mm. The molded body was cured in water for 28 days, and then was cured at 60 ° C. for 24 hours and at 95 ° C. for 8 hours.
After drying for an hour, a concrete molded body was obtained.

Comparative Example 10 A concrete molded body was obtained in the same manner as in Comparative Example 9 except that the surface treating agent of Comparative Example 9 was not adhered.

Comparative Example 11 A concrete molded product was obtained in the same manner as in Example 13 except that the surface treating agent of Example 13 was not adhered.

Table 2 shows the results of evaluating the physical properties of the concrete compacts of "Examples 13 and 14" and "Comparative Examples 5 to 11".

[0061]

[Table 2]

As is clear from Table 2, Examples 13 and 14
It can be seen that the fiber for reinforcing the concrete impact strength of Example 1 is excellent in the effect of reinforcing the concrete. The reinforcing effects of Examples 13 and 14 show a dramatic improvement over the reinforcing effects of Examples 1 to 12. This is a satisfactory value in Examples 1 to 12, but the fiber strength is 7 g / d and the elongation is 70%.
By doing so, the impact absorption energy is significantly increased, and the effect of reinforcing the concrete molded body is dramatically increased.

In Comparative Examples 5 to 11, since the physical properties of the fibers were not at a satisfactory level, the reinforcing effect was not so much observed. Further, in Comparative Examples 6, 8, and 10, there was no surface treatment agent, and the effect of the fiber could not be sufficiently obtained.
The reinforcement effect is not obtained as compared with Comparative Examples 5, 7, and 9. In addition, when comparing Example 13 with Comparative Example 11, even if the fiber properties are at a satisfactory level, the reinforcing effect cannot be sufficiently exhibited because there is no surface treatment agent. That is, the fiber physical properties are fiber strength 5 g / d, fiber elongation 40% or more, more preferably, fiber strength 7
g / d, the fiber elongation is 70% or more, and the effect of the present invention can be obtained by performing a surface treatment with the surface treatment agent.

[0064]

The fiber for reinforcing concrete impact strength of the present invention has an excellent effect of reinforcing concrete impact strength .
Since the strength and elongation of the fiber are high and the binding property with the special surface treating agent is strong, the reinforcing effect can be sufficiently exhibited in the concrete molded body, and the strength of the concrete molded body can be improved. In particular, it was possible to obtain a fiber for reinforcing cement which improved the bending strength, particularly the impact strength, of the concrete molded article due to its high elongation.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI D06M 13/256 D06M 13/256 13/322 13/322 13/325 13/325 (72) Inventor Hiroaki Nishio Yasu, Yasu-gun, Shiga Prefecture 889, Koshinohara-cho, Grand Court Yasu 505 (72) Inventor Kunio Kimura, 218-34, Kayakata-cho, Tosu-shi, Saga Prefecture (72) Inventor, Nori Kamio 56) References JP-A-6-248506 (JP, A) JP-A-4-21556 (JP, A) JP-A-6-135755 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) C04B 16/06

Claims (4)

(57) [Claims] 1. A concrete reinforcing fiber comprising a polypropylene fiber having a single yarn strength of 5 g / d or more and a single yarn elongation of 40% or more, wherein the fiber includes a higher fatty acid metal salt and a higher alcohol sulfate ester metal. Salts, metal salts of higher alkyl ether sulfates, metal salts of alkyl benzene sulfonic acids, metal salts of alkyl benzene naphthalene sulfonic acids, metal salts of paraffin sulfonic acids, alkyl amine salts, alkyl ammonium salts, and having 8 carbon atoms. A fiber for reinforcing concrete impact strength , wherein 0.1 to 10% by weight of a surfactant having an alkyl group of from 22 to 22 is attached to the weight of polypropylene fiber. 2. The concrete impact strength reinforcing fiber according to claim 1, wherein the polypropylene fiber has a single yarn strength of 7 g / d or more and a single yarn elongation of 70% or more. 3. The method according to claim 1, wherein the metal salt is at least one alkali metal salt selected from Na, Li, and K.
The fiber for reinforcing concrete impact strength according to item 1. 4. A concrete molded article formed by using the fiber for reinforcing concrete impact strength according to claim 1.