JP2017222554A - Hydraulic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost hydraulic material having high fracture energy of a hydraulic material hardening body obtained by sufficiently hydrating and curing the hydraulic material.SOLUTION: Provided is a hydraulic material containing reinforcing fiber, as the reinforcing fiber, including aliphatic polyamide fiber whose single fiber strength is 3 to 9 cN/dtex and high strength reinforcing fiber whose single fiber strength is higher than that of the aliphatic polyamide fiber. The hydraulic material contains the aliphatic polyamide fiber by 0.01 to 5 vol% with respect to the hydraulic material, and contains the high strength reinforcing fiber by 0.01 to 5 Vol% with respect to the hydraulic material. As the aliphatic polyamide fiber, nylon fiber essentially consisting of nylon 66 is preferable, and the polymer of the nylon fiber in which a melt flow rate (MFR) at 270°C is 10 to 70 g/10 min is preferable.SELECTED DRAWING: Figure 2

Description

  The present invention provides a water containing an aliphatic polyamide fiber (medium strength aliphatic polyamide fiber) having a single fiber strength of 3 to 9 cN / dtex as a reinforcing fiber and a high strength reinforcing fiber having a single fiber strength higher than that of the aliphatic polyamide fiber. It relates to hard materials.

  In order to increase various mechanical strengths such as compressive strength, bending strength, and tensile strength of hydraulic materials such as cement mortar, concrete, and cement board, various fibers are added as reinforcing fibers in the hydraulic material. Fibers added to hydraulic materials as reinforcing fibers include metal fibers such as steel fibers, inorganic fibers such as glass fibers and rock wool, and organic fibers such as polypropylene fibers, vinylon fibers, nylon fibers, and carbon fibers. Has been. Reinforcing fibers are generally fibers with high single fiber strength, and the reinforcing fibers to be used are selected in consideration of the strength of hydraulic materials and manufacturing costs required from fibers with high single fiber strength. In producing reinforcing fibers for use in hydraulic materials, selection of a polymer as a raw material has been performed in consideration of these factors.

  For example, Patent Document 1 proposes a highly crystalline polypropylene fiber having a specific range of Q value, boiling n-heptane insoluble content, isotactic pentad fraction, and the like. This proposal has the advantage that by using polypropylene with a narrow molecular weight distribution and a uniform molecular weight, the yarn can be easily taken up during spinning, the draw ratio can be increased, and a high-strength fiber can be obtained. Technology. Patent Document 2 proposes a polypropylene fiber having a specific range of isotactic pentad fraction, endothermic peak shape, and amount of change in melting enthalpy. Patent Document 3 proposes a cementitious matrix (hardened cement) to which melt-spun nylon fibers satisfying specific single fiber strength (traction strength) and elongation (elongation rate) are added.

JP 05-170497 A JP 2008-266871 A Japanese Patent No. 4636693

  However, the conventionally proposed polypropylene-based reinforcing fibers are fibers made of a hydrophobic resin, so that the affinity between the polypropylene-based reinforcing fibers and the cement matrix is low, and the hydraulic material is deformed. In this case, it has been pointed out that the fibers easily come off from the cement matrix before the polypropylene fibers break. That is, although the strength of the single fiber is high, the affinity with the cement matrix is low, so that when the hardened hydraulic material is deformed, the reinforcing fibers are pulled out. As a result, the stress-strain curve when deformed has a problem that the initial stress is high but the rate of decrease is large when the strain increases, that is, the fracture energy is low, and further improvement has been demanded. Moreover, since the hydraulic material reinforced with the nylon fiber proposed in Patent Document 3 uses the nylon fiber as the reinforcing fiber, the hydraulic material is excellent in affinity between the reinforcing fiber and the cement matrix. As a result, even if the hydraulic material is deformed, it is difficult for the fibers to come out of the cement matrix. However, since the nylon fibers used have a high elongation (over 30% to less than 225%), the single fiber strength is low ( 2.1 g / de to less than 3.7 g / de), and the nylon fiber is easily broken, and when the hydraulic material is deformed, the added fiber breaks at the initial stage of deformation, It has been pointed out that the initial strength is insufficient.

  In order to solve the above-described conventional problems, the present invention provides a hydraulic material that is low in manufacturing cost and has sufficient initial strength and fracture energy in a hydraulic material that has been sufficiently cured.

  The hydraulic material of the present invention is a hydraulic material including a reinforcing fiber, and the reinforcing fiber includes an aliphatic polyamide fiber having a single fiber strength of 3 to 9 cN / dtex, and a single fiber strength higher than that of the aliphatic polyamide fiber. The high-strength reinforcing fiber includes 0.01 to 5 Vol% of the aliphatic polyamide fiber relative to the hydraulic material, and the high-strength reinforcing fiber includes 0.01 to 5 Vol% relative to the hydraulic material. It is characterized by including.

  When the hydraulic material of the present invention is sufficiently cured by a hydration reaction to form a molded body (hereinafter also referred to as a hydraulic material cured body), the fracture energy is improved. That is, the hydraulic material of the present invention includes an aliphatic polyamide fiber having a single fiber strength of 3 to 9 cN / dtex as a reinforcing fiber, and a high-strength reinforcing fiber having a single fiber strength higher than that of the aliphatic polyamide fiber, The hydraulic material contains aliphatic polyamide fiber in an amount of 0.01 to 5% by volume with respect to the hydraulic material, and the high strength reinforcing fiber is contained in an amount of 0.01 to 5% by volume with respect to the hydraulic material. When a hardened hydraulic material is deformed, which is a characteristic when adding an aliphatic polyamide fiber that satisfies the above requirements to a hydraulic material, the hardened hydraulic material has high fracture energy and maintains high stress even when the strain is large It can be.

FIG. 1 is a schematic front view showing the shape of a dumbbell and a tensile test apparatus used in one embodiment of the present invention. FIG. 2 is an explanatory view showing the breaking energy shown in one embodiment of the present invention.

  The hydraulic material of the present invention uses, as the reinforcing fiber, an aliphatic polyamide fiber having a single fiber strength of 3 to 9 cN / dtex and a high-strength reinforcing fiber having a single fiber strength higher than that of the aliphatic polyamide fiber. The aliphatic polyamide fiber is contained in an amount of 0.01 to 5 Vol% with respect to the hydraulic material, and the high-strength reinforcing fiber is contained in an amount of 0.01 to 5 Vol% with respect to the hydraulic material. This is a characteristic of hydraulic materials with the addition of aliphatic polyamide fibers satisfying specific single fiber strength. When trying to deform a molded product, water with high fracture energy is used to maintain high stress even when the strain is large. Maintaining the point that it becomes a hardened material, and using a high-strength reinforcing fiber having a single fiber strength greater than that of aliphatic polyamide fiber, the hardened material of the hydraulic material has a high initial stress when deformed. It becomes the hardened body which has the point of becoming.

(Aliphatic polyamide fiber)
The aliphatic polyamide fiber contained in the hydraulic material of the present invention, that is, an aliphatic polyamide fiber having a single fiber strength of 3 to 9 cN / dtex (hereinafter, this fiber is also referred to as a medium strength aliphatic polyamide fiber) will be described in detail. explain. In the present invention, the aliphatic polyamide fiber is 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass when the total mass of the aliphatic polyamide fiber is 100% by mass. %, And particularly preferably a fiber substantially composed of an aliphatic polyamide, excluding a fiber treatment agent adhering to the fiber surface, a stabilizer and a flame retardant added during melt spinning. Examples of the aliphatic polyamide include various nylon resins such as nylon 66, nylon 610, nylon 6T, nylon 6I, nylon 9T, nylon M5T, nylon 6, nylon 11, and nylon 12. Of these, nylon 66, nylon 6, nylon 6T, nylon 9T, nylon 11 and nylon 12 are preferred in view of availability, spinning processability, and drawing processability, and nylon 66, nylon 6, nylon 6T, nylon 11, Nylon 12 is more preferable, nylon 66, nylon 6, nylon 11, and nylon 12 are particularly preferable, and nylon 66 is most preferable. Nylon 66 is polyhexamethylene adipamide.

  In the present invention, the medium-strength aliphatic polyamide fiber preferably contains the above-mentioned nylon 66 as a main component. Nylon 66 may be contained in any part of the fiber, but preferably nylon 66 occupies at least a part of the fiber surface. If it is a single fiber, the fiber which nylon 66 occupies at least one part of the fiber surface can be manufactured by melt-spinning the raw material which has nylon 66 as a main component. A composite fiber comprising two or more types of resin components, for example, a core-sheath composite fiber having a concentric cross section, a core-sheath composite fiber having an eccentric structure, a side-by-side composite fiber, a split composite fiber, and a sea-island composite fiber In this case, the resin component including nylon 66 is preferably exposed on the fiber surface. More specifically, in the case of a core-sheath type composite fiber having a concentric circular cross section or a core-sheath type composite fiber having an eccentric structure, it is preferable to use a resin component containing nylon 66 as the sheath component. It is preferable that the resin component containing is a sea component.

  The medium-strength aliphatic polyamide fiber contained in the hydraulic material of the present invention is not particularly limited as long as it is a fiber obtained by melt spinning the above-mentioned aliphatic polyamide resin, but preferably the melt flow at 270 ° C. of the aliphatic polyamide. The rate (MFR) is preferably 10 to 70 g / 10 min. A more preferred melt flow rate is 40 to 70 g / 10 min, a particularly preferred melt flow rate is 50 to 70 g / 10 min, and a most preferred melt flow rate is 55 to 67 g / 10 min. When the MFR of the aliphatic polyamide resin satisfies the above range, yarn breakage and fusion between fibers are less likely to occur in melt spinning, and a stretching process at a high magnification can be performed in the stretching process while suppressing the occurrence frequency of yarn breakage, In addition, the heat setting process can be performed efficiently, so that it can be manufactured at a low cost, and when used as a reinforcing fiber for hydraulic materials, it has high affinity with hydraulic materials and can provide a high reinforcing effect. It becomes a polyamide fiber.

  In the present invention, the melt flow rate (MFR) of the aliphatic polyamide resin is measured at 270 ° C. and a load of 21.2 N according to JIS K 7210. More specifically, the MFR measured by the following method is used as the MFR of the aliphatic polyamide resin in the present invention. First, an aliphatic polyamide sample (aliphatic polyamide resin pellets or manufactured aliphatic polyamide fiber) for measuring MFR is kept in a constant temperature drier set at 100 ° C. for 5 hours and sufficiently dried. Next, the temperature of the extrusion type plastometer according to JIS K 7210 is raised to a predetermined temperature, and after maintaining the predetermined temperature for 20 minutes to stabilize the temperature, 3-8 g of the dried sample is filled. Then, measurement of the melt flow rate is started 360 seconds after filling the sample. The same measurement is repeated twice, and the average value is taken as the melt flow rate of the aliphatic polyamide resin.

  The hydraulic material of the present invention includes an aliphatic polyamide fiber having a single fiber strength of 3 to 9 cN / dtex as a medium strength aliphatic polyamide fiber. When the hydraulic material includes the aliphatic polyamide fiber satisfying the range of the single fiber strength, the fracture toughness of the hydraulic material tends to increase. The single fiber strength of the medium strength aliphatic polyamide fiber is preferably 4 to 9 cN / dtex, more preferably 4.5 to 8.5 cN / dtex, and particularly preferably 5 to 8.5 cN / dtex. Preferably, it is 5.4-8 cN / dtex. Further, the elongation at break of the medium-strength aliphatic polyamide fiber contained in the hydraulic material of the present invention is not particularly limited, but is preferably 10 to 120%, more preferably 15 to 80%, and particularly preferably 20 -70%, most preferably 30-65%. If the single fiber strength and elongation at break of medium-strength aliphatic polyamide fiber are within the above ranges, not only the balance between strength and elongation when used as a reinforcing fiber for a hydraulic material is excellent, but also aliphatic polyamide resin. Since the affinity between the medium-strength aliphatic polyamide fiber and the hydraulic material is increased due to the hydrophilicity, an excellent reinforcing effect on the hydraulic material can be exhibited. In addition, the medium-strength aliphatic polyamide fiber satisfying the above-mentioned single fiber strength and breaking elongation can be efficiently melt-spun, drawn and heat-set, and therefore can be produced at a relatively low production cost. In the aliphatic polyamide fiber, when the single fiber strength is less than 3.0 cN / dtex or the elongation at break exceeds 80%, the strength of the fiber itself is low, so that the reinforcing effect is not imparted to the hydraulic material. In other words, in the hydraulic material that is cured by mixing these fibers, various fracture strengths such as compressive strength, tensile strength, and bending strength are compared with the hydraulic material cured without adding various reinforcing fibers. There is a possibility that improvement cannot be expected. When the single fiber strength of the aliphatic polyamide fiber exceeds 9.0 cN / dtex or the elongation at break becomes less than 15%, the reinforcing effect of the hydraulic material, in particular, the aliphatic polyamide fiber is included. In the hydraulic material of the invention, not only may there be no possibility of further improvement in its fracture energy, but when producing such a high-strength polyamide fiber, production at a higher temperature and higher draw ratio may be possible. Therefore, the manufacturing cost is increased, and as a result, the manufacturing cost of the hydraulic material may be increased.

  The fineness of the medium-strength aliphatic polyamide fiber is not particularly limited, but the fineness is preferably 0.3 to 30 dtex, more preferably 0.5 to 20 dtex, and particularly preferably 0.7 to 15 dtex. Preferably it is 0.8-12 dtex. The fiber length is not particularly limited, but is preferably 1 to 50 mm, more preferably 2 to 40 mm, and particularly preferably 3 to 25 mm. If the fineness and fiber length are within the above ranges, it is miscible with a hydraulic material, for example, a medium strength aliphatic material for a slurry hydraulic material kneaded by adding water to a hydraulic composition such as various cements. The miscibility when adding and kneading polyamide fiber further is good, and fiber floating and fiber lumps (fiber balls) are less likely to occur.

  The cross-sectional shape of the medium-strength aliphatic polyamide fiber is not particularly limited. In addition to a round cross-section, non-circular cross-sections such as a polygonal cross section including a triangle and a quadrilateral, a three-leaf cross section, and a four-leaf cross section Any cross-sectional shape such as a multi-leaf cross-section, Y shape, W shape, or well shape may be used. Moreover, it is good also as a solid fiber which is these cross-sectional shapes, and does not contain a hollow part, and has one or more continuous hollow parts or discontinuous hollow parts with respect to the fiber length direction in a fiber. Also good. In the medium-strength aliphatic polyamide fiber contained in the hydraulic material of the present invention, the fiber cross section is preferably a solid and round cross section. A solid and round cross-section can be manufactured at low cost. The round cross section includes various circles such as a circle, an ellipse, and an ellipse. Moreover, the cross-sectional structure of the nylon fiber for reinforcing a hydraulic material of the present invention is not particularly limited, and may be a single resin component, that is, a single fiber composed of a resin component mainly composed of nylon 66, or a plurality of For example, a core-sheath type composite fiber having a concentric cross section, a core-sheath type composite fiber having an eccentric structure, a side-by-side composite fiber, a split type composite fiber, or a sea-island type composite fiber may be used. .

  The aliphatic polyamide fiber (medium strength aliphatic polyamide fiber) having a single fiber strength of 3 to 9 cN / dtex contained in the hydraulic material of the present invention is shown below when nylon 66 is used as the aliphatic polyamide resin. It can be manufactured and used by a manufacturing method. First, nylon 66 having a melt flow rate at 270 ° C. of 10 to 70 g / 10 min is prepared. The prepared nylon 66 is put into an extruder, melted at a spinning temperature of 260 to 300 ° C., extruded from a spinning nozzle, taken up at a take-up speed of 200 to 2000 m / min, and undrawn fiber having a fineness of 1.5 to 100 dtex. A bundle (also referred to as unstretched tow) is obtained. When the spinning temperature is less than 260 ° C., when the nylon 66 is melted, the melt viscosity is high, and the spinnability may be extremely deteriorated, such as frequent yarn breakage. When the spinning temperature exceeds 300 ° C., the melt viscosity of the nylon 66 is too low, so that not only the unstretched fibers are fused, but the nylon 66 may start to thermally decompose during melt spinning. When nylon 66 fiber is used as the aliphatic polyamide fiber, in the method for producing nylon 66 fiber, a preferable spinning temperature is 270 ° C. to 295 ° C., and a particularly preferable spinning temperature is 270 to 290 ° C.

  The molten resin extruded from the spinning nozzle is taken out at a take-up speed of 200 to 2000 m / min. When the take-up speed is less than 200 m / min, not only the thickness of the nylon 66 fiber constituting the bundle of unstretched fibers is too thick, but the take-up roller is liable to be entangled during production, and the productivity may be reduced. If the take-up speed is higher than 2000 m / min, the unstretched fibers of nylon 66 are likely to be cut at the time of take-up, which may also reduce productivity. Nylon 66 is melt-spun at the spinning temperature and the take-up speed to obtain an unstretched tow that is a bundle of unstretched fibers. The fineness of the nylon 66 fibers constituting the undrawn tow, that is, the fineness of the nylon 66 fibers before the drawing step is 1.5 to 100 dtex. When the fineness of the unstretched fiber of nylon 66 exceeds 100 dtex, it is difficult to obtain a fiber suitable for the reinforcing fiber of the hydraulic material even after the stretching process. When the fineness of the unstretched fiber of nylon 66 is less than 1.5 dtex, yarn breakage is likely to occur during melt spinning, and not only productivity is inferior, but also the draw ratio is lowered in the stretching process, and the resulting nylon 66 is obtained. The single fiber strength of the fiber tends to be low.

  The non-stretched tow of the obtained nylon 66 is subjected to a stretching step, a heat setting step, and then cut to a desired fiber length to thereby obtain a medium-strength aliphatic polyamide fiber contained in the hydraulic material of the present invention. As an example, nylon 66 fiber is obtained. The unstretched tow of the obtained nylon 66 is subjected to a stretching treatment. After wet stretching using warm water at 10 to 80 ° C., heat setting is performed in a dry state at 100 to 200 ° C. (hereinafter also referred to as dry heat setting). .) To do. It is known that the secondary transition point (glass transition point) of nylon is 40-50 ° C. in a dry state, but is −20-0 ° C. in a hygroscopic state (“Fiber Encyclopedia”). , Page 793, left column, lines 2 to 14, March 25, 2002, Maruzen), because the above range allows efficient stretching. The heat setting in the dry state is more preferably performed at a temperature of 100 to 180 ° C., and particularly preferably 120 to 160 ° C. When heat setting is performed within the above-mentioned temperature range in a dry state, strong heat fixation can be achieved and dimensional stability can be obtained. The wet stretching is preferably performed at a stretching ratio of 2 to 6 times. If the draw ratio is less than 2 times, the drawing is not sufficiently performed, so that the single fiber strength of the obtained nylon 66 fiber is low, and the strength of the hydraulic material may not be improved. In the wet drawing step, when the draw ratio exceeds 6 times, yarn breakage frequently occurs and the productivity may be lowered. The heat setting step is preferably a constant length heat setting performed at a draw ratio that does not sag when the treatment is performed, and may be performed at a draw ratio of 0.85 to 1.5 times.

  In addition, the production method of the medium-strength aliphatic polyamide fiber contained in the hydraulic material of the present invention is not limited to the production method described above. That is, the medium-strength aliphatic polyamide fiber contained in the hydraulic material of the present invention may be an aliphatic polyamide fiber having a single fiber strength of 3 to 9 cN / dtex, and preferably has a melt flow rate range at 270 ° C. It is a fiber using a polyamide resin to be satisfied, and more preferably, an aliphatic polyamide fiber satisfying fiber properties such as fineness, fiber length, or elongation at break can be used.

  The hydraulic material of the present invention contains 0.01 to 5 Vol% of aliphatic polyamide fiber (medium strength aliphatic polyamide fiber) having a single fiber strength of 3 to 9 cN / dtex. That is, in the hydraulic material, it is divided from the hydraulic material, in other words, among the hydraulic materials, medium strength aliphatic polyamide fibers, high strength reinforcing fibers and other reinforcing fibers used as needed (medium The total of components such as cement, fine aggregate, coarse aggregate, water, etc., excluding high-strength aliphatic polyamide fibers and reinforcing fibers other than high-strength reinforcing fibers) is 100 vol%. Contains 0.01-5Vol%. By including medium-strength aliphatic polyamide fibers in the above ratio, the hydraulic material of the present invention can not only increase the breaking energy of the cured hydraulic material, but also the hydraulic material before curing, that is, in a slurry state. In this hydraulic material, the fluidity can be maintained to some extent, so that the workability is hardly hindered. When the ratio of the medium strength aliphatic polyamide fiber contained in the hydraulic material is less than 0.01% by volume, the amount of the medium strength aliphatic polyamide fiber contained in the hydraulic material is small. There is a possibility that the fracture energy of the material is not much different from that of a hydraulic material to which medium strength aliphatic polyamide fiber is not added. When the ratio of the medium strength aliphatic polyamide fiber contained in the hydraulic material exceeds 5 Vol%, not only the manufacturing cost of the hydraulic material increases, but also various mechanical strengths such as compressive strength and tensile strength may be lowered. The ratio of the medium strength aliphatic polyamide fiber contained in the hydraulic material of the present invention is preferably 0.05 to 3 Vol%, more preferably 0.1 to 2.5 Vol%, and 0.2 to 2.0 Vol. % Is particularly preferred.

(High-strength reinforcing fiber)
The hydraulic material of the present invention comprises an aliphatic polyamide fiber (medium strength aliphatic polyamide fiber) having a single fiber strength of 3 to 9 cN / dtex as a reinforcing fiber, and a single fiber strength of the aliphatic polyamide fiber (the medium strength fat). High-strength reinforcing fibers that are larger than the single fiber strength of the group polyamide fiber). The high-strength reinforcing fiber is not particularly limited as long as it is a medium-strength aliphatic polyamide fiber, that is, a fiber having a single fiber strength higher than that of an aliphatic polyamide fiber having a single fiber strength of 3 to 9 cN / dtex. It can be used as a high-strength reinforcing fiber contained in a hard material. The high-strength reinforcing fiber contained in the hydraulic material of the present invention includes polypropylene, ethylene-propylene copolymer, low density polyethylene, linear low density polyethylene, high density polyethylene, ultrahigh molecular weight polyethylene, and ethylene-vinyl alcohol. Organics such as polymers, polymethylpentene, polyolefin fibers mainly composed of cyclic polyolefin and olefin elastomer, polyacetal fibers, vinylon fibers, semi-aromatic polyamide fibers, wholly aromatic polyamide fibers (also called aramid fibers), carbon fibers, etc. In addition to fibers, inorganic fibers such as ceramic fibers such as rock wool, glass fibers, and alumina fibers, metal fibers including so-called steel fibers, and aliphatic polyamide fibers whose single fiber strength exceeds 9 cN / dtex are reinforced with high strength. An example of fiber. Among these fibers, considering the reinforcing effect that can be imparted to the hydraulic material, the manufacturing cost, etc., the high-strength reinforcing fibers are polypropylene fibers, ultrahigh molecular weight polyethylene fibers, ethylene-vinyl alcohol copolymer fibers, polymethyl resins. It is preferably at least one selected from pentene fiber, polyacetal fiber, vinylon fiber, wholly aromatic polyamide fiber, carbon fiber, steel fiber, and aliphatic polyamide fiber having a single fiber strength exceeding 9 cN / dtex. It is more preferably at least one selected from molecular weight polyethylene fiber, polyacetal fiber, vinylon fiber, wholly aromatic polyamide fiber, carbon fiber, steel fiber, polypropylene fiber, ultrahigh molecular weight polyethylene fiber, polyacetal fiber, vinylon fiber, wholly aromatic Group polyamide fiber, carbon Particularly preferred is at least one selected from fibers.

  In the high-strength reinforcing fiber included in the hydraulic material of the present invention, when the high-strength reinforcing fiber includes a metal fiber including a steel fiber, the fiber diameter of the metal fiber is not particularly limited, but the fiber diameter is 0.05 to It is preferably 2 mm, more preferably 0.1 to 1.5 mm, and particularly preferably 0.2 to 1 mm. The fiber length of the metal fiber is not particularly limited, but the fiber length is preferably 3 to 120 mm, more preferably 5 to 100 mm, and particularly preferably 10 to 80 mm. If the fiber diameter and fiber length of the metal fiber contained as the high-strength reinforcing fiber are within the above ranges, the miscibility with the hydraulic material is good.

  In the high-strength reinforcing fiber contained in the hydraulic material of the present invention, when the high-strength reinforcing fiber is an inorganic fiber (excluding metal fiber) such as glass fiber, rock wool, and various ceramic fibers, the fiber diameter of the inorganic fiber is particularly Although not limited, the fiber diameter is preferably 3 to 100 μm, more preferably 5 to 80 μm, particularly preferably 8 to 50 μm, and most preferably 10 to 30 μm. The fiber length of the inorganic fiber is not particularly limited, but the fiber length is preferably 2 to 120 mm, more preferably 3 to 100 mm, and particularly preferably 5 to 80 mm. If the fiber diameter and fiber length of the inorganic fiber contained as the high-strength reinforcing fiber are within the above ranges, the miscibility with the hydraulic material is good.

  The high-strength reinforcing fiber contained in the hydraulic material of the present invention is a fiber whose single fiber strength is greater than the single fiber strength of the medium-strength aliphatic polyamide fiber. The medium-strength aliphatic polyamide fiber contained in the hydraulic material of the present invention has a certain degree of single fiber strength, but has a certain degree of elongation for the purpose of imparting toughness at break to the hydraulic material. Therefore, when only medium-strength aliphatic polyamide fiber is added to the hydraulic material as a reinforcing fiber, the tensile strength, compressive strength, bending strength, etc. in the hydraulic material are due to low single fiber strength. In the mechanical strength, there is a possibility that the initial strength, that is, the strength at the time when cracks (cracks) are first generated is lowered. In addition to the medium-strength aliphatic polyamide fiber, when a fiber having a single fiber strength higher than this fiber is added as a high-strength reinforcing fiber, the high-strength reinforcing fiber having a single-fiber strength higher than that of the medium-strength aliphatic polyamide fiber can be hydraulic. The initial strength of the material is increased, and the amount of energy required for breaking the hydraulic material is increased by the elongation of the medium strength aliphatic polyamide fiber. The single fiber strength of the high-strength reinforcing fiber is not particularly limited as long as it is greater than the single-fiber strength of the medium-strength aliphatic polyamide fiber, but the single-fiber strength of the high-strength reinforcing fiber is the single-fiber strength of the medium-strength aliphatic polyamide fiber. Is preferably 1.05 times or more, more preferably 1.1 times or more, particularly preferably 1.15 times or more, and most preferably 1.2 times or more.

  The case where the high-strength reinforcing fiber included in the hydraulic material of the present invention is a polypropylene fiber will be described. Polypropylene fiber is not only easy to manufacture and excellent in manufacturing cost, but also has excellent alkali resistance and chemical resistance, and has long been used as a reinforcing fiber for hydraulic materials. When polypropylene fiber is used as the high-strength reinforcing fiber, the polypropylene resin to be used is not particularly limited, and may be a propylene homopolymer. Propylene and other α- having about 2 to 20 carbon atoms. It may be a copolymer with olefin. Examples of other α-olefins having about 2 to 20 carbon atoms include ethylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and the like can be mentioned. In the propylene copolymer, the propylene content is preferably 90 mol% or more, more preferably 95 mol% or more, and further preferably 98 mol% or more. Since high-strength fibers can be obtained in terms of stereoregularity, the isotactic pentad fraction (IPF: mol%) is preferably 90% or more, more preferably 93% or more, and still more preferably 94% or more. Polypropylene resin can be used. In addition, IPF is good to measure according to "macromolecules, Vol.6,925 (1973) and Macromolecules, Vol.8,687 (1975)" about an n-heptane insoluble component.

  Although it does not specifically limit as said polypropylene resin, In the extending process which extends | stretches the fiber of an unstretched state when Q value (Mw / Mn) is less than 6, since it can be extended | stretched by a high draw ratio, a high intensity | strength fiber is obtained. It is preferable because it is easy to obtain and yarn breakage or the like hardly occurs even when drawn at a high draw ratio. The Q value is more preferably less than 5, and still more preferably less than 4.

  When using a polypropylene fiber as the high-strength reinforcing fiber contained in the hydraulic material of the present invention, the single fiber strength of the polypropylene fiber is greater than the single fiber strength of the medium-strength aliphatic polyamide fiber used together, and The single fiber strength is 6.0 to 18 cN / dtex, more preferably 6.2 to 15 cN / dtex, particularly preferably 6.5 to 12 cN / dtex, and most preferably 6.8 to 10 cN / dtex. When the single fiber strength of the polypropylene fiber satisfies the single fiber strength, the strength until cracks (cracks) are first generated in the hydraulic material is improved. In addition, the medium strength aliphatic polyamide fiber used in combination increases the amount of fracture energy until the hydraulic material breaks, so the resulting hydraulic material has high initial strength and high fracture energy. Become a material. Moreover, when using a polypropylene fiber as the high-strength reinforcing fiber, the breaking elongation of the polypropylene fiber is preferably 5 to 45%, more preferably 10 to 45%, and more preferably 15 to 40%. Particularly preferred is 18 to 38%.

  When polypropylene fibers are used as the high-strength reinforcing fibers contained in the hydraulic material of the present invention, the fineness of the polypropylene fibers is not particularly limited, but the fineness is preferably 0.3 to 30 dtex, more preferably 0. .5 to 20 dtex, particularly preferably 0.7 to 15 dtex, and most preferably 0.8 to 12 dtex. Further, the fiber length is not particularly limited, but the fiber length is preferably 1 to 50 mm, more preferably 3 to 40 mm, and particularly preferably 3 to 25 mm. If the fineness and fiber length are within the above ranges, the miscibility with the hydraulic material, for example, the polypropylene fiber is used for the slurry-like hydraulic material kneaded by adding water to a hydraulic composition such as various cements. In addition, the miscibility at the time of kneading is good, and fiber floating and fiber lumps (fiber balls) are less likely to occur.

  Next, the case where the high-strength reinforcing fiber included in the hydraulic material of the present invention is a vinylon fiber will be described. Vinylon fiber is not only easy to manufacture and excellent in manufacturing cost, but also because the resin itself has high affinity with water, that is, it is a synthetic fiber that has high hydrophilicity. Used as a reinforcing fiber. When vinylon fiber is used as the high-strength reinforcing fiber contained in the hydraulic material of the present invention, the vinylon fiber is saponified polyvinyl alcohol (PVA), and its saponification degree is preferably 85 mol% or more. . A saponification degree of 99 mol% or more facilitates crystallization and not only provides high-strength vinylon fibers, but also makes vinylon fibers difficult to absorb moisture, resulting in a decrease in single fiber strength of vinylon fibers due to moisture absorption. Can be suppressed. The saponification degree of the saponified polyvinyl alcohol used for the vinylon fiber is more preferably 90 mol% or more, particularly preferably 95 mol% or more, and most preferably 98 mol% or more.

  When vinylon fiber is used as the high-strength reinforcing fiber contained in the hydraulic material of the present invention, the single fiber strength of the vinylon fiber is larger than the single fiber strength of the medium-strength aliphatic polyamide fiber used together, and vinylon The single fiber strength measured with the fibers dried is 7.0-30 cN / dtex, more preferably 7.4-25 cN / dtex, particularly preferably 7.6-20 cN / dtex, most preferably 7.8- 18 cN / dtex. When the single fiber strength of the vinylon fiber satisfies the single fiber strength, the strength until a crack (crack) is first generated in the hydraulic material is improved. And since the amount of fracture energy until the hydraulic material breaks due to the medium strength aliphatic polyamide fiber used in combination, the resulting hydraulic material has a large initial strength and a large fracture energy. It becomes. In the present invention, the single fiber strength measured in a state where the vinylon fiber is dried is defined as JIS L 1015 for the vinylon fiber which is dried by holding the vinylon fiber in a constant temperature dryer set at 105 ° C. for 2 hours. It refers to the single fiber strength measured in conformity.

  In the hydraulic material of the present invention, the case where fibers other than polypropylene fibers and vinylon fibers are used as the high-strength reinforcing fibers will be described. When using a fiber other than polypropylene fiber or vinylon fiber as the high-strength reinforcing fiber, a fiber from which a fiber having a high single fiber strength can be easily obtained, specifically, an ultrahigh molecular weight polyethylene fiber, a wholly aromatic polyamide fiber, It is preferable to use carbon fibers. Ultra high molecular weight polyethylene fiber, wholly aromatic polyamide fiber and carbon fiber are high in production cost, but can easily be obtained with a single fiber strength exceeding 20 cN / dtex. Can be used against. In the hydraulic material of the present invention, when an ultra high molecular weight polyethylene fiber is used as the high strength reinforcing fiber, the single fiber strength of the ultra high molecular weight polyethylene fiber is preferably 10 to 100 cN / dtex, and 15 to 80 cN / dtex. Is more preferable, and it is especially preferable that it is 20-60 cN / dtex. In the hydraulic material of the present invention, when a wholly aromatic polyamide fiber (also referred to as aramid fiber) is used as the high-strength reinforcing fiber, the single fiber strength of the wholly aromatic polyamide fiber is 10 to 80 cN / dtex. It is preferably 12 to 50 cN / dtex, more preferably 15 to 30 cN / dtex. In the hydraulic material of the present invention, when carbon fiber is used as the high-strength reinforcing fiber, the single fiber strength of the carbon fiber is preferably 10 to 100 cN / dtex, and more preferably 12 to 60 cN / dtex. It is particularly preferably 15 to 30 cN / dtex. When an ultrahigh molecular weight polyethylene fiber, wholly aromatic polyamide fiber, or carbon fiber is used as the high-strength reinforcing fiber, the hydraulic material exhibits a very high initial strength, which is preferable.

  The hydraulic material of the present invention contains 0.01 to 5 Vol% of the high-strength reinforcing fiber. That is, in the hydraulic material, it is divided with respect to the hydraulic material, in other words, among the hydraulic material, the high-strength reinforcing fiber, the medium-strength aliphatic polyamide fiber, and other reinforcing fibers used as required (high The total sum of components such as cement, fine aggregate, coarse aggregate, water, etc., excluding strength reinforcing fibers and reinforcing fibers other than medium strength aliphatic polyamide fibers) is set to 100 Vol%. Contains 01-5Vol%. In addition to the medium strength aliphatic polyamide fiber having a single fiber strength of 3 to 9 cN / dtex, the hydraulic material contains fibers having a single fiber strength higher than that of the fiber as a high-strength reinforcing fiber in the above-described ratio. The hydraulic material is not only hydrated and cured, but also a cured material obtained by curing and exhibits a high initial strength, as well as a hydraulic material before curing, that is, a slurry-like hydraulic material. In the composition, since the fluidity can be maintained to some extent, the workability is hardly hindered. If the ratio of the high-strength reinforcing fiber contained in the hydraulic material is less than 0.01 Vol%, the initial strength of the cured hydraulic material may not be sufficient. If the proportion of the high-strength reinforcing fiber contained in the hydraulic material exceeds 5 Vol%, not only the manufacturing cost of the hydraulic material increases, but also the proportion of the reinforcing fiber in the hydraulic material increases too much. And various mechanical strengths such as tensile strength may be reduced. The ratio of the high-strength reinforcing fiber contained in the hydraulic material of the present invention is preferably 0.05 to 3 Vol%, more preferably 0.1 to 2.5 Vol%, and 0.2 to 2.0 Vol%. Is particularly preferred.

  The hydraulic material of the present invention has an aliphatic polyamide fiber having a single fiber strength of 3 to 9 cN / dtex (for medium-strength aliphatic polyamide fiber) and a single fiber strength greater than the single fiber strength of the aliphatic polyamide fiber. A hydraulic material containing high-strength reinforcing fibers. The hydraulic material of the present invention is added to the hydraulic material composition so as to contain medium strength aliphatic polyamide fiber and high strength reinforcing fiber in a certain ratio with respect to the hydraulic material composition such as various cements, and an appropriate amount of the hydraulic material composition. Add water, knead well and then harden, or add medium strength aliphatic polyamide fiber and high strength reinforcing fiber to the hydraulic material slurry that is already mixed with hydraulic material composition and water, and knead well Then, it can be obtained by curing. The hydraulic material composition contained in the hydraulic material of the present invention includes various cements, fine aggregates, and coarse aggregates, admixtures and admixtures as necessary. As the cement constituting the hydraulic material composition, various cements such as ordinary Portland cement, early strength Portland cement, super early strength Portland cement, moderately hot Portland cement, low heat Portland cement, sulfate resistant Portland cement, etc. should be used. Can do. As fine aggregate and coarse aggregate constituting the hydraulic material composition, silica sand, river sand, sea sand, beach sand, crushed stone, various slag such as blast furnace slag, ferronickel slag, copper slag, electric furnace umbrella slag, etc. From these, the particle diameter of the aggregate can be selected according to the use of the hydraulic material, and it can be used as a fine aggregate or a coarse aggregate. As an admixture contained in the hydraulic material composition, fly ash, silica stone powder, silica fume, blast furnace slag fine powder, ettringite and various known expanding materials can be used. Admixtures contained in the hydraulic material composition include AE agent, AE water reducing agent, high function AE water reducing agent, fluidizing agent, curing accelerator, rust preventive agent, setting retarder, rapid setting agent, shrinkage reducing agent. Various admixtures such as those can be appropriately selected and used depending on the purpose and application.

  The hydraulic material of the present invention includes an aliphatic polyamide fiber (medium strength aliphatic polyamide fiber) having a single fiber strength of 3 to 9 cN / dtex as a reinforcing fiber of the hydraulic material, and a single fiber strength of the aliphatic polyamide fiber. In addition, a high-strength reinforcing fiber larger than the single fiber strength is included. The hydraulic material of the present invention may contain other fibers as necessary in addition to the medium-strength aliphatic polyamide fiber and the high-strength reinforcing fiber as the reinforcing fiber. Examples of the reinforcing fibers other than the medium-strength aliphatic polyamide fiber and the high-strength reinforcing fiber include natural fibers having small single fiber strength, such as jute fiber, sisal hemp fiber, and bamboo fiber, and the medium-strength aliphatic fiber. Examples thereof include chemical fibers having a single fiber strength smaller than that of polyamide fibers.

  In the hydraulic material of the present invention, the ratio of reinforcing fibers to the hydraulic material, that is, reinforcing such as medium strength aliphatic polyamide fiber, high strength reinforcing fiber, reinforcing fiber that is neither medium strength aliphatic polyamide fiber nor high strength reinforcing fiber, etc. The ratio of the sum of all fibers to the entire hydraulic material is preferably 0.02 to 7 Vol%. That is, in the hydraulic material, it is divided with respect to the hydraulic material, in other words, among the hydraulic materials, medium strength aliphatic polyamide fiber, high strength reinforcing fiber, and other reinforcing fibers used as necessary ( The sum of the components such as cement, fine aggregate, coarse aggregate, water, etc., excluding medium strength aliphatic polyamide fibers and fibers other than high strength fibers) is set to 100 Vol%, and the total of reinforcing fibers is 0.02 It is preferable to contain ~ 7Vol%. Since the hydraulic material contains reinforcing fibers such as medium-strength reinforcing fibers and high-strength fibers in the above proportions, water with excellent initial strength and breaking energy without adversely affecting the fluidity and workability of the hydraulic material slurry. A hard material can be obtained. When the ratio of the reinforcing fiber contained in the hydraulic material is less than 0.02 Vol%, the amount of the fiber contained in the hydraulic material is small, so that the initial strength is improved and the fracture energy is increased due to the addition of the fiber. An increase is not seen and there exists a possibility that the effect which added the fiber may not fully be exhibited. When the ratio of the reinforcing fibers contained in the hydraulic material exceeds 7 Vol%, not only the fiber ball is easily generated when adjusting the hydraulic material slurry, but also the fluidity of the hydraulic material slurry decreases, and the construction site In addition to the ease of workability being reduced, the mechanical strength such as compressive strength and bending strength of the cured hydraulic material may decrease due to the excessive proportion of reinforcing fibers contained in the hydraulic material. There is. The proportion of the reinforcing fibers contained in the hydraulic material of the present invention is preferably 0.07 to 6 Vol%, more preferably 0.1 to 5 Vol%, particularly preferably 0.12 to 3 Vol%, 0 Most preferably, it is 15 to 2.5 Vol%. The hydraulic material of the present invention may contain, in addition to the medium-strength aliphatic polyamide fiber and the high-strength reinforcing fiber, a reinforcing fiber that is neither the medium-strength aliphatic polyamide fiber nor the high-strength reinforcing fiber. It is preferable that high-strength aliphatic polyamide fibers and high-strength reinforcing fibers are included and no other fibers are included.

  The hydraulic material of the present invention has a maximum tensile stress value (A) within a strain range of 0 to 4% and a tensile stress value (B) when the strain is 4% in a tensile stress test of a cured hydraulic material. ) Is preferably 30% or more of A, more preferably 40% or more. If it is the said range, even if distortion becomes large, the tensile stress (strength) of a molding can be maintained high.

  The fracture energy obtained from the tensile stress and displacement area of the cured hydraulic material is preferably 1.4 times higher than that of the cured hydraulic material that does not include reinforcing fibers. If it is the said range, even if distortion becomes large similarly, the tensile stress (strength) of a hydraulic material hardening body can be maintained high, and it becomes a hydraulic material hardening body which is hard to be destroyed.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited to the following Example.

<Measurement method>
(1) Melt flow rate (MFR)
The melt flow rate of nylon 66 was measured according to JIS K 7210 at 270 ° C. and a load of 21.2 N. Specifically, a sample of nylon 66 (resin pellet or manufactured fiber) whose melt flow rate is to be measured is kept for 5 hours in a constant temperature dryer set at 100 ° C. and sufficiently dried. Next, the temperature of the extrusion type plastometer according to JIS K 7210 is raised to 270 ° C. and kept at 270 ° C. for 20 minutes to stabilize the temperature, and then 3 to 8 g of the dried sample is filled. Then, measurement of the melt flow rate is started 360 seconds after filling the sample. The same measurement was repeated twice, and the average value was taken as the melt flow rate of nylon 66 at 270 ° C.
(2) Single fiber strength and elongation at break Using a tensile tester according to JIS L 1015, the load value and elongation at the time of fiber cutting when the gripping interval of the sample was 20 mm were measured. The strength and elongation at break were taken.
(3) Tensile test of cured hydraulic material Tensile test using a uniaxial tensile test using a dumbbell-type test body 1 having a total length of 330 mm, a grip width of 60 mm, a thickness of 30 mm, a constriction width of 30 mm, and a length of 80 mm shown in FIG. Stress and strain were measured. This tensile test is based on JIS K6301. The test apparatus 10 fixes the test body 1 with the chucks 2a and 2b, and then pulls it up and down to measure the tensile stress, and measures the strain with the displacement meters 3a and 3b. In the right figure of FIG. 1, the numerical value is the dimension (unit: mm) of the dumbbell specimen.

(Examples 1-5, Comparative Examples 1-7)
(Polypropylene fiber used as high-strength reinforcing fiber)
A fiber made of a homopolypropylene resin used as a high-strength reinforcing fiber of the hydraulic material of the present invention was produced by the following procedure. A polypropylene resin (propylene homopolymer, manufactured by Nippon Polypro Co., Ltd., product name “SA01A”, Q value: 3.0) was melt extruded at a spinning temperature of 270 ° C. using a spinning nozzle having a circular nozzle hole shape, Drawing was performed at a take-up speed of 1000 m / min to produce a 9 dtex spun filament (undrawn yarn). Using the obtained spinning filament, dry-stretching (single-stage stretching) 4.5 times at 140 ° C., a hydrophilic fiber treatment agent containing phosphoric acid ester potassium salt as a main component, and the mass of the fiber as 100 After adhering so that the proportion of the active ingredient was 0.3% by mass, the fiber length was cut to 6 mm. The obtained polypropylene fiber (hereinafter also referred to as “PP fiber”) had a single fiber fineness of 2.2 dtex, a single fiber strength of 7.41 cN / dtex, and a breaking elongation of 27%.

(Other high-strength reinforcing fibers)
Polypropylene fibers (hereinafter also referred to as PP fibers) are prepared as high-strength reinforcing fibers, and other commercially available polyvinyl alcohol fibers (hereinafter also referred to as PVA fibers), and commercially available high-strength polyethylene fibers. (Hereinafter also referred to as PE fiber) was prepared. The prepared PVA fiber had a fineness of 13.5 dtex, a single fiber strength of 13.4 cN / dtex, a breaking elongation of 6%, and a fiber length of 8 mm and 12 mm. The prepared PE fiber had a fineness of 1.29 dtex, a single fiber strength of 26.8 cN / dtex, a breaking elongation of 4%, and a fiber length of 6 mm and 12 mm.

(1) Production of medium-strength aliphatic polyamide fiber As medium-strength aliphatic polyamide fiber, a fiber made of nylon 66 resin was produced by the following procedure. A spinning nozzle having a circular nozzle hole shape made of nylon 66 resin (manufactured by Asahi Kasei Co., Ltd., product name “Leona 1300S”, MFR measured at 270 ° C. and 21.2 N is 63.63 g / 10 min. According to JIS K 7210) Was used for melt extrusion at a spinning temperature of 285 ° C. to produce a spun filament (unstretched yarn) having an unstretched fineness of 40.5 dtex. Using the obtained spinning filament, after wet-drawing at a draw ratio of 4.9 in a bath adjusted to a water temperature of 23 ° C., tension was applied at a draw ratio of 1.05 times between metal rolls adjusted to 140 ° C. Performing heat setting, the ratio of the phosphate ester potassium salt to the obtained filament after stretching is a hydrophilic fiber treatment agent containing phosphate ester potassium salt as a main component and the fiber mass is 100. After making it adhere so that it might become 0.3 mass%, it cut | disconnected to fiber length 6mm, and obtained nylon 66 fiber 1 (it is also described as "Ny66-1" hereafter). This fiber (Ny66-1) had a fineness of 9.06 dtex, a single fiber strength of 5.94 cN / dtex, and a breaking elongation of 52%.
(2) As medium-strength aliphatic polyamide fiber, commercially available nylon 66 fiber 2 (hereinafter also referred to as “Ny66-2”) was prepared. This fiber (Ny66-2) had a fineness of 3.25 dtex, a single fiber strength of 3.94 cN / dtex, and an elongation at break of 86%.

  As will be described later, a specimen of a cured hydraulic material was prepared, and a tensile test was performed on the specimen. In Examples 1 to 5, as shown in Table 2, the nylon 66 fiber (Ny66-1 or Ny66-2) is used as a medium strength aliphatic polyamide fiber, and the PP fiber is used in combination as a high strength reinforcing fiber. Comparative Example 1 is a cured body of a hydraulic material obtained by adding PP fiber alone to the hydraulic material, and Comparative Examples 2 to 7 do not use aliphatic polyamide fibers. As shown in Table 3, the cement hardened body is reinforced by using a plurality of fibers other than aliphatic polyamide fibers. Table 1 shows the materials used for the hydraulic material.

  Using materials shown in Table 1, 70 parts by mass of cement, 30 parts by mass of fly ash, 40 parts by mass of fine aggregate, 0.2 parts by mass of thickener, 0.9 parts by mass of water reducing agent, 39.1 parts by mass of water And the amount of the reinforcing fibers shown in Tables 2 and 3 was uniformly mixed to prepare a hydraulic material slurry. The fiber content (Vol%) of the reinforcing fiber shown in Tables 2 and 3 is the volume ratio of the fiber to the total volume of 100% of cement, fly ash, fine aggregate, thickener, water reducing agent and water, excluding the reinforcing fiber. It is. In the mixing method, cement, fly ash and fine aggregate powder are first kneaded for 1 minute, then water, a water reducing agent and a thickener are added and mixed for 3 minutes, and then reinforcing fibers are added. Mixed 5 times x 2 times. The hydraulic material slurry thus obtained was placed in a mold and cured in water to produce the dumbbell shown in FIG. Using this dumbbell, a tensile test was performed to determine the initial crack strength and fracture energy. As shown in FIG. 2, the fracture energy can be expressed as stress degree × displacement = fracture energy amount. The evaluation results are summarized in Table 2.

  As apparent from Tables 2 and 3, the hydraulic material cured bodies of Examples 1 to 5 had high fracture energy. This is because the cured hydraulic material of Examples 1 to 5 not only has excellent affinity with cement as a reinforcing fiber, but also contains an aliphatic polyamide fiber that retains a certain degree of elongation. Even if the deformation becomes larger, the aliphatic polyamide fiber is stretched according to the deformation without being pulled out from the cement matrix, so that it is presumed that the fracture energy is increased by increasing the stress degree of the specimen. In the hydraulic material cured body of the example, when Example 1 and Example 4, Example 2 and Example 5 are compared, Examples 4 and 5 have lower values of fracture energy. This is because the aliphatic polyamide fiber contained in the hydraulic material of Examples 4 and 5 is a fiber having a single fiber strength of 3 to 9 cN / dtex. Since the aliphatic polyamide fiber itself is broken before the fiber is pulled out or pulled out of the cement matrix, it is considered that the breaking energy is slightly reduced. Therefore, in the hydraulic material of the present invention, it can be said that the aliphatic polyamide fiber contained in the hydraulic material is preferably a fiber having a certain high single fiber strength.

  In contrast to the hydraulic material cured bodies of the examples, no remarkable improvement in fracture energy was confirmed in the hydraulic material cured bodies of Comparative Examples 1 to 7. In the cured hydraulic material of Comparative Example 1, the reinforcing fiber used was only PP fiber, and the value of the fracture energy was lower than that of any of the Examples. This is because, in addition to the small amount of reinforcing fibers contained in the cured hydraulic material of Comparative Example 1, only the fibers made of hydrophobic resin are included, and therefore the reinforcing fibers are successively added when the distortion of the cured hydraulic material increases. This is thought to be due to the sudden drop in the stress level.

  Unlike Examples, medium strength aliphatic polyamide fibers are not used, and the cured hydraulic materials of Comparative Examples 2 to 4 using PP fibers and PE fibers in combination also contain the same proportion of reinforcing fibers. The fracture energy is lower than that of the cured hydraulic material. That is, when the hydraulic material cured body of Examples 1 and 2 and the hydraulic material cured body of Comparative Examples 2 and 3 were compared, and the hydraulic material cured body of Example 3 and the hydraulic material cured body of Comparative Example 4 were compared, The value of the fracture energy is lower in the cured hydraulic material of the comparative example than in the cured hydraulic material of the example including the aliphatic polyamide fiber. This is because the reinforcing fibers contained in the hydraulic materials of Comparative Examples 2 to 4 are PP fibers and PE fibers, and both are fibers made of a hydrophobic resin. Therefore, it is considered that when the cured hydraulic material is deformed, both PP fibers and PE fibers are pulled out, and the fracture energy is not improved.

  Unlike Examples, medium strength aliphatic polyamide fibers were not used, and the cured hydraulic materials of Comparative Examples 5 to 7 using PP fibers and PVA fibers in combination also contained reinforcing fibers in the same proportion. The fracture energy is lower than that of the cured hydraulic material. That is, when the hydraulic material cured body of Examples 1 and 2 and the hydraulic material cured body of Comparative Examples 5 and 6 were compared, and the hydraulic material cured body of Example 3 and the hydraulic material cured body of Comparative Example 7 were compared. The value of the fracture energy of the cured hydraulic material of the comparative example is lower than that of the cured hydraulic material of the example including the aliphatic polyamide fiber. This is because the reinforcing fibers contained in the hydraulic materials of Comparative Examples 5 to 7 are PP fibers and PVA fibers, and the PVA fibers have high hydrophilicity, that is, fibers that have high affinity with the cement matrix. The fiber has a low elongation of 6%. For this reason, when the cured hydraulic material is deformed, unlike the fibers made of hydrophobic resin, the pulling out from the cement matrix can be suppressed, but the fibers do not stretch and the fibers break and the breaking energy is reduced. It is thought that it did not improve.

  The hydraulic material of the present invention includes an aliphatic polyamide fiber (medium strength aliphatic polyamide fiber) having a single fiber strength of 3 to 9 cN / dtex as a reinforcing fiber, and a high strength whose single fiber strength is greater than that of the aliphatic polyamide fiber. It is a hydraulic material containing reinforcing fibers, and by making it a fully cured hydraulic material cured product, it becomes a hydraulic cured product having high fracture energy that cannot be exhibited by conventional hydraulic materials. Such hydraulic materials exhibiting high fracture energy are required not only to be used for structural materials of various large buildings where hydraulic materials are generally used, but also to be not completely destroyed even when impact is applied. It is considered to be a hydraulic material that is particularly suitable for applications that require resistance to destruction even when subjected to physical impact, such as highway walls, tunnel structures, and protective shelters. .

DESCRIPTION OF SYMBOLS 1 Test body 2a, 2b Chuck 3a, 3b Displacement meter 10 Test apparatus

Claims (6)

A hydraulic material containing reinforcing fibers,
The hydraulic material includes, as the reinforcing fiber, an aliphatic polyamide fiber having a single fiber strength of 3 to 9 cN / dtex, and a high-strength reinforcing fiber having a single fiber strength larger than that of the aliphatic polyamide fiber,
The hydraulic material contains 0.01 to 5 Vol% of the aliphatic polyamide fiber with respect to the hydraulic material,
The hydraulic material includes the high-strength fiber in an amount of 0.01 to 5 Vol% with respect to the hydraulic material.   The hydraulic material according to claim 1, wherein the aliphatic polyamide fiber has a fineness of 0.3 to 30 dtex, a fiber length of 1 to 50 mm, and a breaking elongation of 10 to 100%.   The hydraulic material according to claim 1, wherein the aliphatic polyamide fiber is solid and has a round cross section.   The hydraulic material according to any one of claims 1 to 3, wherein the aliphatic polyamide fiber is a fiber mainly composed of nylon 66 having a melt flow rate (MFR) at 270 ° C of 10 to 70 g / 10 min.   The ratio of the single fiber strength of the high-strength reinforcing fiber to the single fiber strength of the aliphatic polyamide fiber (single fiber strength of the high-strength reinforcing fiber / single fiber strength of the aliphatic polyamide fiber) is 1.05 or more. The hydraulic material in any one of -4.   6. The fiber according to claim 1, wherein the high-strength reinforcing fiber is one or a plurality of fibers selected from polypropylene-based fibers, ultrahigh-density polyethylene fibers, wholly aromatic polyamide fibers, vinylon fibers, carbon fibers, and steel fibers. The hydraulic material according to crab.

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