JPS60215559A - Fiber for cement mortar or concrete reinforcement and product therefrom - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to fibers that have excellent reinforcing properties for cement mortar or cement concrete, and to cement mortar and concrete molded products reinforced with the fibers.

Hardened products of hydraulic substances such as cement, typified by Portland cement, are used in large quantities in the fields of architecture and civil engineering because of their excellent properties such as compressive strength, durability, and nonflammability, as well as their low cost.

3- However, since it is a brittle material, it has extremely low bending resistance, and has disadvantages such as easily breaking or cracking when stress such as tensile or bending is applied, and low impact resistance. . In order to compensate for these drawbacks, reinforcing bars and steel frames are used in combination, and methods of adding fibers are also known.

The molded product of the present invention can be made by adding a matrix mainly composed of a hydraulic substance such as cement, fibers, and the minimum amount of water, and then pouring the product into a mold as it is, or by dry molding using a molding method using various molding machines. The water is intentionally removed and remains as the hardening water of the matrix. The strength of hardened cement is determined by the ratio of water to cement during molding (
It is common knowledge that the smaller the W/C (hereinafter abbreviated as W/C), the smaller the amount of water added, the higher the strength development. Practically, the range of W/C in which cement mortar or concrete has fluidity (workability), that is, workability, is used in the range of W/C = 0.1 to 1, which is a limited range of use. There is.

4- As mentioned above, this dry molding method uses a small amount of water, so it has poor fluidity and is thin and long, that is, the aspect ratio [the ratio of the fiber diameter d to the length 1 (1/d)] It is very difficult to incorporate dog fibers (referred to as "ratio"), and although studies have been carried out, sufficient effects have not been achieved.

First of all, from the viewpoint of workability, when fibers are added to cement mortar or concrete, the fluidity of this mortar or concrete is impaired, making it impossible to mix wires, and even if cross-mixing is possible, fiber balls, so-called fiber lumps, are formed. The resulting cement, mortar or aggregate may separate, making it extremely difficult to handle the cement mortar or concrete, resulting in poor workability and unusable use.

Furthermore, some inorganic fibers such as glass fibers are damaged by cross-mixing and even lose their properties as reinforcing fibers.

From the point of view of reinforcing properties, since the added fibers are not uniformly dispersed in the cement mortar, that portion becomes defective and no reinforcing properties are exhibited. On the other hand, in order to disperse the fibers uniformly in cement mortar, the shape of the fibers is made thick and short. However, although the fibers are uniformly dispersed in this case, the woven fabric pulls out when subjected to bending force, and a satisfactory reinforcing effect cannot be obtained.

The surface is textured to prevent the fibers from pulling out from the matrix.

Furthermore, specifically, steel fibers are among the reinforcing fibers that have been studied the most and have been put into practical use to some extent. The shape of the fibers varies, but the round cross section has an equivalent diameter of approximately 0.5 cm, and the length is 20~
30 square meters and an aspect ratio of approximately 40 to 60 is used. As the aspect ratio increases, the handling and construction properties of multi-fiber fibers become worse. For example, measures are taken when adding and mixing materials, such as using products that are lined up and packed in boxes in order to prevent them from forming into fiber balls during transportation, or using a disintegrating machine such as a dispenser. Furthermore, when observing the fracture surface of concrete reinforced with steel fibers after bending failure or tensile failure, the steel fibers are definitely pulled out and the fibers themselves are not broken at all. In other words, the aspect ratio is small and the adhesion with the cement matrix is poor, so the tensile strength of steel fibers (70 to 100 kr/
+yJ) is not fully utilized, and no significant reinforcing effect can be expected. Furthermore, spraying using steel fibers requires operations such as rebound of the fibers and protrusions on the surface after molding.
Due to its ease of handling, it can pierce the eyes, skin, and body, which is a disadvantage in terms of safety and economy.

Furthermore, molded products using steel fibers are disadvantageous in terms of weight reduction because of the problem of deterioration of appearance due to rusting, expansion of cracks, peeling, and other troubles in the fiber chamber.

Furthermore, alkali-resistant glass fibers are being considered as bundled yarns. Glass itself is a brittle material and is very brittle and easily breaks, so to prevent this from happening, bundled threads are used.

However, if even chopped strands in the form of bundled yarns are directly added to cement mortar or concrete and mixed and stirred, they will break and break into pieces due to shearing force, and the reinforcing effect cannot be expected. Therefore, only a special molding method can be used in which chopped strands are sprayed separately without being mixed with mortar. In addition, even with alkali-resistant glass fibers, there are concerns about alkali resistance, and durability remains a problem.

As an example of using organic synthetic fibers, for example, Japanese Patent Application Laid-open No. 1983-
85457 uses very thick and relatively short polyolefin fibers such as polyethylene with a thickness of 100 to 5000 deniers and a length of 5 to 100 m, and aims to improve dispersibility in cement paste and workability from the aspect of morphology. It is said that However, since such thick and short reinforcing fibers are pulled out, the reinforcing properties are not improved. In particular, polyolefin has poor adhesion to cement. So in this example,
The aim is to create irregularities on the peripheral surface of the fibers to physically anchor them to the matrix, and to obtain a reinforcing effect by the snagging. However, the strength of polyolefin-based fibers is not very strong even when the fineness is fine, and it decreases significantly when the fineness is increased. It is extremely difficult to produce high-strength, thick-fiber monofilaments. For example, the polyethylene fiber Bonfix (trade name manufactured by Mitsui Petrochemicals) has an equivalent diameter of 0.9 ky/-, a low tensile strength of 26 ky/-, and an improvement in bending strength, according to the catalog. I can't wait.

In Cement Concrete Magazine (A23], May 1966 issue, p. 2), Mori et al.
Length: 5 to 25 mm LD There have been reports of improved dispersibility and impact resistance of polyvinyl alcohol (hereinafter abbreviated as PVA) fibers by using surfactants and the like. However, in this report, foaming during construction,
Problems such as no improvement in bending strength remain. ○ JP-A-59-8664 specifies monofilaments of PVA fibers with a fineness of 100 to 1000 denier, It is not possible to obtain a strength with a high Young's modulus, for example, as shown in the example, a maximum of 80
The Young's modulus is considered to be about 17 ooh/-.

Therefore, if we try to further increase the reinforcing properties, we will have to increase the addition rate of fibers, which will lead to problems with fiber dispersibility and workability.

Also @βto1an58-124608A・Yoto 1987-
In No. 13662, a sizing agent that has no sizing effect in the presence of water is used in the reinforcing fibers to improve mixability with cement when no water is added as chopped strands, and chopped strands are created by adding water afterwards. It is characterized by the fact that the strands are fibrillated into monofilaments, which improves dispersibility and provides a reinforcing effect.

The fineness of the PVA% fiber is 05 to 25 denier, the tensile strength is 90, and the monofilament aspect ratio is 00 to 200.
At 0, more than 20% of the cement molded product is made up of single fibers.
! ! : It is characterized by being thin. This is a good method for uniformly dispersing high aspect ratio, high strength, high Young's modulus fibers in mortar.

On the other hand, since a water-soluble sizing agent is used, the M longitude is affected by humidity and varies depending on the composition at the time of construction, the cross-wire method or cross-wire time, the mortar transport time, and the environmental conditions such as air holes and wind and rain. In particular, if the flow value and slump value change over time, uniform spraying and pouring during construction cannot be achieved, and complicated management is required, which is impractical. Furthermore, since the fineness when fibrillated into monofilaments is as thin as 0.5 to 25 deniers, the fluidity of fresh mortar or concrete is extremely poor, making handling difficult.

As mentioned above, as reinforcing fibers for cement mortar and concrete, fibers that are thick and have an appropriate length should be added in as small a quantity as possible from the viewpoint of workability. In terms of reinforcing properties, the fibers have high strength, high Young's modulus, and excellent adhesion to the matrix. From a usage perspective, physical safety during handling,
It is important that the material satisfies the requirements such as being lightweight, durable, and economical.

As mentioned above, it is difficult to satisfy these conditions with inorganic fibers, and even with thick monofilaments of organic synthetic fibers. Therefore, the inventors of the present invention have made extensive studies on a bundled yarn that is made by binding high-strength multifilaments and solidifying them with a binding agent.

The conditions that such a bundled yarn should have as fibers for reinforcing cement mortar and concrete are as follows.

1. Workability during construction should not be reduced by adding reinforcing fibers.

(1) fJ! Fibers do not adhere to each other due to the influence of the sizing agent or become entangled during transportation (this prevents easy insertion of fibers). No deterioration (no generation of fiber balls or separation of mortar and aggregate) (8) No decrease in slump over time during transportation of fresh concrete using mortar mixers.

(4) There should be no problems with fresh mortar, concrete molded products, pump pressure delivery, etc.

(5) Must have finishability.

2. Reinforcement properties can be ensured.

Under the conditions where the above workability, plasticity, and finishability are ensured, (1) the adhesive strength between the fiber and the matrix is excellent0 (2) the adhesive strength between single fibers and single fibers is excellent0 (8) Single fibers must have excellent tensile strength and Young's modulus (4) The sizing agent must be water and alkali resistant, easily adhere to the cement matrix, and have flexibility.

As a result of intensive research to satisfy these conditions, we have arrived at the present invention.

Single fiber denier is 0.5 to 25 denier, tensile strength is 110 ky/11Ij or more, and Young's modulus is 3000
kg/- or more of organic synthetic fibers with a yarn denier of 200 to 5,000 denier per 1 meter.
After twisting ~700 times (abbreviated as T/m), the fiber was
The fibers are uniformly impregnated with a hydrophobic polymer sizing agent of 2 to 50% by weight, and the strands are cut to an aspect ratio of 20 to 300. Even when added to cement mold or concrete, fresh concrete becomes workable. It is a reinforcing fiber. Using such fibers, 0.1 to 10 volumes of the fibers were added using a matrix consisting of a hydraulic substance such as cement and, if necessary, fine aggregate, coarse aggregate, and/or other additives. It is possible to provide cement mortar or concrete moldings that are workable without impairing the workability of fresh mortar or concrete and are highly reinforced with fibers.

In particular, the organic synthetic fibers that can be used include PVA fibers, polyacrylonitrile fibers, polyamide fibers, polyolefin fibers, and aramid fibers.

The polymeric sizing agent is preferably an emulsion of various copolymers such as hydrophobic ethylene-vinyl acetate-vinyl chloride. A polymer sizing agent that does not impair the flexibility of the organic synthetic fibers and has a flexible resin is preferable so that the sizing fibers do not break.

The present invention will be explained in more detail.

14- The organic synthetic fiber used as the bundled yarn may be obtained by various spinning methods including wet, dry, dry-wet, and melt spinning methods. PV
A fiber (which may or may not be acetalized), high-strength polyacrylonitrile fiber, nylon 6.
Polyamide fibers such as 66, polyolefin fibers such as high-strength polyethylene and high-strength polypropylene, polyester filaments, and aramid synthetic fibers such as Kepler and HM-50 can be used. However, the material is not limited to the above, and any organic synthetic fiber that satisfies the physical properties specified in the present invention may be used.

When using organic synthetic fibers as reinforcing materials for hydraulic materials such as cement, fibers with high strength and Young's modulus are required. The tensile strength of these long fibers is 1] Okf/
It is necessary that the Young's modulus is 2300 kg/- or more.

The fineness of the single fiber denier of 0.5 to 25 denier is generally used to improve the sophistication and uniformity of the internal structure of the single fiber, such as high orientation and high crystallinity due to high stretching. You can get the same percentage. If the denier of the single fiber is less than 0.5 denier, the fineness is too small and is disadvantageous in terms of manufacturing troubles and economical efficiency.If the denier is 25 denier or more, it has sufficient strength and strength to be used as a reinforcing fiber. It is difficult to obtain the Young's modulus, and as the fineness of the single fiber increases, the adhesion area between the fibers decreases and the focusing effect decreases, which is not preferable.

Organic synthetic fibers obtained by various spinning methods are bundled into a suitable denier. It is preferable that the binding is done during spinning, but it may also be a method of twisting the wound fibers. An appropriate denier is 200 to 5,000 deniers, which is determined by the fineness and fiber length that will be effective as reinforcing fibers. If the yarn denier is less than 200 denier, the fineness is small and handling is poor, and if it is more than 5,000 denier, the yarn will be undesirably uneven as it will become uneven. More preferably, it has a denier of 500 to 3,000.

The most important thing for the effectiveness of the present invention is to twist the focused yarns. The appropriate number of twists is 50 to 700 twists per meter (T/m). The twist coefficient has a value of 18 to 1257, preferably 54 to 750. However, the twist coefficient is expressed as the product of the number of twists per inch and the square root of the yarn fineness. 50T
If the number of twists is less than /m, the number of twists is small, the effect of twisting is small, fibrillation occurs during kneading with mortar, and the flow value decreases, making it unfavorable for handling. Moreover, if it exceeds 700 T/m, the uniform impregnation of the sizing agent may be impaired, the elongation may increase due to shrinkage during twisting, and the reinforcing property may deteriorate. Furthermore, since the yarn is highly twisted, productivity is poor and it is economically disadvantageous. Particularly preferably 150 to 400 T/m. By twisting in this way and further converging with a hydrophobic polymer, the integration of the high strength fibers is further enhanced.

As a result, even if it is strongly kneaded in cement mortar or concrete for a long time, it will not be defibrated and workability can be ensured. The entire fiber can bear the stress from the cement matrix evenly. In addition, twisting creates unevenness on the surface of the fibers, which can catch on the cement matrix and make it difficult to pull out, which improves the contradictory performance of workability and reinforcing properties.

Polymer sizing agents include hydrophobic ethylene-vinyl acetate-vinyl chloride copolymer (abbreviated as E/VAc/VC), ethylene-vinyl acetate copolymer (abbreviated as E/VAC), and ethylene-acetic acid. Emulsions of vinyl-acrylic copolymers, polyvinyl acetate homopolymers, acrylic esters, etc. can be used. Furthermore, latexes such as styrene-butadiene copolymers (SBR), acrylonitrile butadiene copolymers (NBR), acrylates, and vinyl chloride can be used. These emulsions and latexes can be used alone or in combination. These sizing agents have film-forming properties, are water resistant and alkali resistant, and have no tackiness, so they are easy to handle. In particular, E/VAc/VC has good performance. Furthermore, hot melt adhesives can also be used, and epoxy adhesives can also be used. It is common to apply the sizing agent by dipping, and repeat impregnating and squeezing with a squeezer such as 18-silol to remove excess sizing agent. In the case of emulsion or latex, the concentration used is 50-50 (1/l), and the adhesion rate to the yarn is preferably 2-50%.The reason why the adhesion rate is 2-50% is 2% or less. Even if the yarn is a twisted yarn, it will loosen when mixed with cement mortar, resulting in poor workability.

If the adhesion ratio is 50 degrees or more, the amount of polymeric sizing agent in the fiber increases and the shear strength decreases due to an increase in apparent fineness, so that the strength of the yarn is not fully utilized. In addition, the adhesion spots cause the polymer layer to have a large fE<, causing cohesive failure of the polymer sizing agent between the cement and the yarn, and between the single fibers, which is disadvantageous in terms of reinforcing properties.

The drying temperature of the polymer sizing agent is preferably 80 to 250°C.
The temperature is preferably 120 to 200°C. Furthermore, it is desirable to carry out the treatment at 150 to 250 DEG C. in order to adhere the polymer sizing agent to the fiber from the inside to the surface by heat treatment. The drying process mainly involves drying the surface of the sizing agent, and can be carried out using hot air or heated rolls in order to improve process passability and prevent gum buildup on the machine stand.

Drying is preferably carried out at 130 to 250°C in the case of a hot air type, and 80 to 150°C in the case of a hot roller type.

The bundled yarn thus obtained can be cut into a predetermined length using a cutting machine to obtain the desired bundled yarn. Regarding the cutting length, an aspect ratio of 20 to 300 is appropriate in view of crosstalk with cement mortar, reduction in slump during crosscrossing, and manifestation of reinforcing effect in the molded body. When the aspect ratio is 20 or less, the dispersibility and crosstalk in fresh concrete are good, and there is little decrease in slump, but since the fibers are short, they tend to pull out from the matrix, and the reinforcing effect is small. Moreover, if it is more than 30 (1), the fiber length becomes long, resulting in poor wire crossing and dispersibility, and as a result, the expected reinforcing properties cannot be obtained. A value of 40 to 150 is preferable.

When such fibers are added to a brittle material such as cement that uses a hydraulic substance as a binder, the binder used is ordinary Portland cement, such as ordinary Boltrad cement, early-strength Portland cement, medium-heat Portland cement, and sulfate-resistant Portland cement, white Portland cement is used. The mixed cement is not limited either, and blast furnace cement, silica cement, and fly ash cement can also be used, as well as alumina cement, expansive cement, and ultra-early strength cement. Other binders such as slag type and magnesia can also be used.

Fine aggregates such as river, sea, and terrestrial sand, crushed sand, and crushed stone are used as aggregates. Ground stone or crushed stone is used as coarse aggregate.

It is also possible to use slag, limestone, pearlite, charcoal, vermiculite, shirasu, etc. as artificial lightweight aggregates or fillers.

It is also possible to use an AE agent, a fluidizing agent, a water reducing agent, a thickening agent, a water retaining agent, and a water repellent in combination as admixtures.

Glauber's salt, gypsum, which has traditionally been used as a curing accelerator,
Sodium carbonate, calcium carbonate, triethanolamine, and calcium chloride can also be used in combination.

21- Sodium silicate, potassium dichromate, and sodium silicofluoride can be used as quick-setting agents, and powder quick-setting agents such as soda carbonate and sodium aluminate can be used as main ingredients for spraying crack repair, etc. It is also possible to use admixtures.

Setting retarders such as lignin sulfonate, oxycarboxylic acid, or inorganic magnesium fluorosilicate, Rittal, etc. can be used.

When the fibers are added to the above-mentioned hydraulic matrix such as cement, the appropriate addition rate is 0.1 to 10% by volume. If the addition rate is less than 0.1 volume, the fiber addition rate is small, so the workability is good.
The crosstalk with the matrix deteriorates, and furthermore, the fibers separate from the aggregate or mortar, making it impossible to withstand construction. The conditions for obtaining reinforcing properties without impairing workability with fresh concrete or mortar are 0.1 to 0 volume. The fibers according to the present invention, which preferably have a volume of 0.5 to 5%, are introduced into cement mortar, and there is almost no change in flow value or decrease in slump over time during construction, resulting in improved construction performance. It was found that the bending strength was improved to 2 to 3 times that of plain by adding a small amount of fiber, and the stress-sag curve showed that it had several tens of times the toughness.

This performance can be widely applied to the civil engineering and architectural fields. First, building-related members include exterior materials, which can be used for shell structures such as single roofing materials, curtain wall outer wall panels, roofing materials such as molded tiles, parabets, spandrels, and exterior reliefs. Furthermore, it can be used as interior material for wall materials, reliefs, floor materials, and ceiling materials. Other materials include formwork, disposable formwork, floor boards, beams, machine platform foundations, nuclear reactor pressure vessels, liquefied petroleum gas containers, partitions in buildings, and staircase materials. Second, as concrete products, it can also be used for sheet piles formed by molding, hollow cylindrical products such as pipes, piles, balls, etc.

As concrete products for roads, it can be used for concrete slabs for sidewalks, reinforced concrete U shapes, concrete and reinforced concrete L shapes, concrete boundary blocks, and reinforced guardrails. Pipes include centrifugal reinforced concrete pipes made by centrifugal forming, span pipes with sockets, reinforced concrete pipes, roll compacted reinforced concrete pipes, unreinforced concrete pipes, prestressed concrete pipes with cores, and asbestos cement pipes for water supply. It can also be used for crafted water pipes and warm water drainage products.

As a shoring product, it can be used for reinforced concrete sheet piles and prestressed concrete sheet piles. It can also be used as a formwork or waste formwork used as a molding formwork. Pipes include sewer pipes, electric lamp pipes, cable ducts, etc.

Further, as road components, it can be used as soundproofing materials, road signs, pavement reinforcement materials, side gutters, tunnel interior materials, piles, etc. For balls and piles, it can also be used for centrifugal curve-rested concrete balls, centrifugal reinforced concrete balls, and centrifugal reinforced concrete piles. As marine or fishery components, it can be used for thin shell structure compositions to be used as cement materials for ferrocement such as marine equipment and boats, floats, floating bridges, fishing reefs, wave-dissipating blocks such as tetrapods, and seawall blocks.

As agricultural and livestock-related components, it can be used for tanks, silos, seedbeds, fence pots, pots, flower pots, and sheet piles for gutters, etc. It can also be used for materials such as containers for processing waste such as radioactive materials.

Thirdly, in terms of application to the civil engineering field, it is concrete road pavement including general roads and airport runways. The purpose of this field is to improve bending and impact strength through fiber reinforcement, as well as to improve its resistance to bumping.It is possible to reduce the amount of reinforcing bars and the thickness of concrete slabs, shorten construction periods, and reduce raw material costs. It is effective in reducing the amount of Furthermore, the spraying method is effective in protecting slopes, and just spraying a thin layer shows its bending strength, and since the fibers are hydrophilic, there is little rebound.

Similarly, construction by spraying inside tunnels (for example, NATM construction method) is also possible, and because the fibers are flexible, elastic, hydrophilic, and lightweight, there is less reversal of aggregate and fibers, and concrete It is effective in terms of yield and safety, as it also reduces the amount of water falling. It can also be used as an earthquake-resistant member and as a concrete member when constructing a bridge. It can also be used for products for slabs and girders, and can be widely applied to prestressed concrete girders for slab bridges, prestressed concrete girders for girder bridges, prestressed concrete bridge girders for light load slab bridges, and prestressed concrete double varnish slabs. It can also be used for overlays, paving of pedestrian bridges, paving of bridge decks, repair materials thereof, sidewalk boards, etc. Fourthly, for special molding, it can be added to cement mortar extrusion molding material to improve bending strength and impact strength. In addition, spraying can be used not only to prevent cracking but also to improve impact resistance and bending strength by adding the fibers as mortar and wall coating mortar. There are no limitations on the use of other materials.

Next, examples and comparative examples will be explained.

26- Example] and Comparative Example 1 Single fiber denier is 1.8 denier, its tensile strength is 152 ky/rxj s, and its Young's modulus is 3500 kp
/m7 and the number of filaments is 10.
00 PVA fibers (product name 5501 manufactured by Kuraray Co., Ltd.) were twisted at 180 T/m and used as a polymer sizing agent with E/V.
Ac/VC copolymer emulsion triple emulsion (trade name Sumikaflex 830) was adjusted to a concentration of 250 f/l and deliquified by immersion to give an adhesion rate of 20% to the yarn. On the other hand, as Comparative Example Test 2, yarns that were not twisted were treated with the same sizing agent and the adhesion rate was set at 20. Furthermore, as a comparative example tester 3, twisting was applied at 180 T/m, and PVA (trade name: Popal 117, manufactured by Kuraray Co., Ltd.) was used as a polymer flocculant.
was immersed to a concentration of 50 f/l and deliquified to give an adhesion rate of 20 inches to the yarn. The drying conditions were as follows: hot air drying at 180° C. in both Examples and Comparative Examples to obtain bundled yarns. All of these fibers were cut into 44 pieces with an aspect ratio of 9o.

One volume of this fiber was added to a mortar with sand/cement-1 and W/C=0.4, and the flow value was measured at regular intervals using a Hobart mixer, a mixing machine according to JIS R5201 (cement test method). Changes were measured. Table the results.
Shown in 1.

~29- As the cement, ordinary Portland cement manufactured by Onoda Corporation was used, and as the sand, standard sand from Toyoura was used.

As shown in Table 1, crosstalk was investigated for up to 1 hour, and the decrease in flow value of test plate 1 of the example was very small. However, as can be seen from Comparative Example Test A2, even when a hydrophobic sizing agent was used, the fibers without twisting were defibrated during kneading and the shear flow value decreased, making it impossible to knead.

In Test Cliff 3, which used a water-soluble sizing agent, the fibrillation was severe and the flow value suddenly decreased, making it impossible to knead. , rIs A 1103 (Aggregate washing test method)
When observed in Example 1, only a portion of the bundled yarn was observed to be bent after 30 to 60 minutes had elapsed.

More than 60 to 80% of the fiber balls of the comparative example were defibrated.

Example 2 and Comparative Example 2 The cement was ordinary Portland cement manufactured by Onoda Corporation, the sand was a mixture of Toyoura standard sand at a ratio of 1=1, and the W/C ratio was 0.
37, and to this mortar Example 1
The bundled yarn made in the above was cut into 44cm and 59III+ pieces with aspect ratios of 30-90 and 120. 1.35, 2.7 volumes of the corresponding fibers were added, J
A mortar was prepared by kneading for 10 minutes according to the mixing method of IS R5201.

For comparison, Blaine mortar with no added fiber, Shinko fiber (required by Kobe Steel),
Fresh mortar was made by mixing 5φ x 25m with a volume of 1.35.2.7. Each flow value was also measured. Pour the corresponding mortar into a 4X4X16 formwork and heat it at 20° for one day and night.
C. Cured in humid air, then cured in water at 20°C for 2 weeks,
Furthermore, the bending strength was measured by curing for two weeks in air at 20° C. and 65% RH. The bending strength was measured using an Instron TT-CM, and a curve deflection diagram was obtained under a concentrated load at the center with a span of 10 cm. This curve is shown in Figure 1 (
a) Shown in (b). From that curve, the proportional limit strength (L
OP) and maximum breaking strength (MOR, ) were calculated.

The crosstalk properties of the mortars in Tests A4 to A7 of Example 2 were similar to those of Tests 8, 9, and 10 of Comparative Example 2, and the fluidity was similar to that of Tests A4 to A7 of Comparative Example 2, and the handling properties were unchanged.

Observation of the cracking state during bending strength measurement revealed that in Example 2, as the load increased, many microcracks were generated from the central loading portion, and the deflection also increased.

However, Test Black 8 of Comparative Example 2 was plain and broke at the maximum load (LOP). Also, with Jra 9.10, as soon as visible cracks appear at maximum load, the stress begins to decrease and only resistance remains to pull out the steel fibers.
No microcracks were observed.

Regarding the bending strength, the LOP strength of Example 2 was also increased compared to the test grave 8. However, although the LOP of Test) A9.10 increased, the MOR of the example shows that it has greater reinforcing properties.

Looking at the toughness from FIGS. 1A and 1B, Example 2 shows a much larger value than Comparative Example 2.

33-Example 3 and Comparative Example 3 In order to examine the reinforcing effect of concrete IJ-t, crushed stone with a maximum diameter of 20 mm was used as the coarse aggregate, and Iwami silica sand was used as the fine aggregate.
O W/C=O155, unit water amount 2] OkS+, unit cement amount 383, fine bone was mixed using a tilting mixer for 10 minutes with a fine aggregate ratio of 0.6 and the following composition. To material 916, crushed stone 611 gin and 0.04% of Takemoto Yushi's Chewball C as an AE water reducing agent were added to the cement, so that the target air content was 5%.

P produced in Example 1 was added to the fresh concrete.
VA fiber cut into 59III+ with an aspect ratio of 20, fineness of 760 denier, tensile strength of 300 ky/mA, Young's modulus of 1.3 x 10'kf
/- Kepler 49 (manufactured by DuPont) was treated in exactly the same manner as in Example 1, and 1 volume of each cut into 34 squares having the same aspect ratio was added. For comparison, one volume of steel fiber (required by Kobe Steel) Shinko fiber 0.5φ x 25m was added to the formulation of Example 3, and plain concrete was prepared without adding 34cm of fiber.

Such fresh conch') -1' OX].

It was poured into a mold of X40cn1, cured in a humid atmosphere at 20℃ day and night, and cured in water at 20℃ for 28 days. Using a universal testing machine RH-200 manufactured by Shimadzu Corporation, the bending strength was determined to be second grade with a span of 30tM. The equinox central loading method was used.

Compressive strength was measured according to JISA-1114. The results are shown in Table-3.

Table 3 Testum] Both the PVA fiber of No. 1 and the Keplerian fiber of A12 showed an improvement in LOP and MOH, and it was found that the reinforcing effect was large. - 413 lines for comparison)
．． No. 14 had little reinforcing effect.

[Brief explanation of the drawing]

Figures 1 (a) and (b) show the bending stress-deflection curves of molded products for each test in Examples and Comparative Examples;
) is the case when the fiber addition rate is 1.35% by volume, and (b) is the case when the fiber addition rate is 2.7% by volume. Patent Applicant RiRa Shi Co., Ltd. Agent Patent Attorney Honji Ken No. 1 (曵) Dawako (c starvation) No. 1 ('O) Ryoya# (c ki)

Claims (1)

[Claims] 1. Single fiber denier is 0.5 to 25 denier, tensile strength is 110 kW/MJ or more, and Young's modulus is 2300 kf.
An organic synthetic fiber with a yarn denier of /- or more of 20
0 to 5000 denier 50 to 7 per meter
After twisting the fibers 00 times, the fibers were fixed with an aqueous polymer sizing agent having a weight coefficient of 2 to 50 to give an aspect ratio of 2.
Reinforcing fiber for cement mortar or concrete cut into 0 to 300 pieces. 2. The cement mortar according to claim 1, wherein the reinforcing fiber material is an organic synthetic fiber selected from polyvinyl alcohol, polyacrylonitrile, polyamide 1, polyolefin, or aramid. Or reinforcing fiber for concrete. 3. The reinforcing fiber for cement mortar or concrete according to claim 1, wherein the hydrophobic polymer sizing agent is an ethylene-acetic acid and 1-nyl-vinyl chloride copolymer. 4. A hydraulic substance, an organic synthetic fiber having a single fiber denier of 0.5 to 25 denier, a tensile strength of 10 kf/- or more, and a Young's modulus of 2300 gin/- or more, with a yarn denier of 200 to 500.
0 denier fibers are twisted 50 to 700 times per meter, and the fibers are fixed with an aqueous polymer sizing agent having a weight ratio of 2 to 50 to give an aspect ratio of 20 to 300.
A fiber-reinforced cement mortar or concrete molded product, which is made of reinforcing fibers cut into pieces, and fine aggregate, coarse aggregate, and/or additives as necessary, and in which the reinforcing fibers are mixed in 0.1 to 10 volumes. . 5. The material of the reinforcing fiber is an organic synthetic fiber selected from polyvinyl alcohol, polyacrylonitrile, polyamide, polyolefin, or aramid, as stated in paragraphs 2-4 of the patent application. fiber-reinforced cement mortar or concrete moldings. 6. The fiber-reinforced cement mortar or concrete molded product according to claim 4, wherein the hydrophobic polymer sizing agent for the reinforcing fibers is an ethylene-hinyl acetate-vinyl chloride copolymer. 7. The fiber-reinforced cement mortar or concrete molded product according to claim 4, characterized in that the blending amount of reinforcing fibers is 0.5 to 5 volumes.