JP2019137582A - Fiber-reinforced concrete and cement mortar - Google Patents

Abstract

To provide fiber-reinforced concrete that has high mechanical strength and good workability.SOLUTION: Fiber-reinforced concrete according to the present invention includes fibrous materials containing SiO, in which the total surface area of the fibrous materials contained per 1 mof the fiber-reinforced concrete is 1×10mor more and 2×10mor less. A diameter of the fibrous material is preferably 6 μm or more, and the fibrous material is preferably in a bundle form.SELECTED DRAWING: Figure 3

Description

  The present invention relates to fiber reinforced concrete and mortar.

  Conventionally, a technique for increasing the mechanical strength of concrete by adding a fibrous material composed of a polymer compound or an inorganic compound to concrete is known.

  For example, Patent Document 1 reports that the toughness of concrete can be improved by adding non-metallic inorganic fibers having a specific value of “focusing bond degree” obtained by multiplying the inverse of the mortar adsorption amount by 100. Yes.

  However, when adding a fibrous substance to concrete in this way, it is necessary to add the fibrous substance to the mortar that is the raw material of the concrete and knead it. However, when a fibrous substance is added to the mortar, the viscosity is improved and the fluidity is lowered, so that the workability is deteriorated. Therefore, there is room for further improvement in order to obtain concrete having both high workability and high strength.

Japanese Patent Laid-Open No. 11-79804

  The present invention has been made in view of the above circumstances, and an object thereof is to provide fiber reinforced concrete having high mechanical strength and good workability, and mortar as a raw material thereof.

The present inventors added a fibrous substance containing SiO ₂ contained in 1 m ^{3 of} fiber reinforced concrete so that the total surface area becomes a ratio of 2 × 10 ³ m ² or less, and further the total surface area. 1 × 10 ⁻² m ² or more, or by making the content of the fibrous material 0.0001% by mass or more, a fiber reinforced concrete having high mechanical strength and good workability can be obtained. The headline and the present invention were completed. Specifically, the present invention provides the following.

(1) A fiber reinforced concrete containing a fibrous material containing SiO ₂ ,
The fiber-reinforced sum of the surface area of the fibrous material contained per concrete 1 m ³ is ² × ¹⁰ 3 ^m 2 or less 1 × ¹⁰ -2 ^{m 2} or more, the fiber-reinforced concrete.

(2) A fiber reinforced concrete containing a fibrous material containing SiO ₂ ,
The content of the fibrous substance is 0.0001% by mass or more based on the total amount of the fiber reinforced concrete,
Fiber reinforced concrete in which the total surface area of the fibrous substances contained per 1 m ^{3 of the} fiber reinforced concrete is 2 × 10 ³ m ² or less.

(3) A fiber reinforced concrete containing a fibrous material containing SiO ₂ ,
The total surface area of the fibrous material contained per 1 m ^{3 of the} fiber reinforced concrete is 2 × 10 ³ m ² or less, and the bending strength measured according to JIS R 5201 does not include the fibrous material. Fiber reinforced concrete that is 1.05 times or more the bending strength of concrete of the same component.

  (4) The fiber reinforced concrete according to any one of (1) to (3), wherein the fibrous substance has a diameter of 6 μm or more.

  (5) The fiber reinforced concrete according to any one of (1) to (4), wherein the fibrous substance is a bundle.

  (6) The fiber reinforced concrete according to any one of (1) to (5), wherein the content of the fibrous substance is 10% by mass or less.

  (7) The fiber reinforced concrete according to any one of (1) to (5), wherein the content of the fibrous substance is 1% by mass or less.

  (8) The fiber reinforced concrete according to any one of (1) to (7), wherein the fibrous substance is a basalt fiber.

(9) The fibrous material containing SiO ₂ is contained, and the total surface area of the fibrous material contained per 1 m ^{3 of the} concrete is 1 × 10 ⁻² m ² or more and 2 × 10 ³ m ² or less with respect to the concrete. Concrete reinforcing agent to be added and used.

(10) The fibrous material containing a fibrous material containing SiO ₂ , wherein the content of the fibrous material is 0.0001% by mass or more based on the total amount of the concrete and 1 m ^{3 of the} concrete. A concrete reinforcing agent for use by adding so that the total surface area of the substances is 2 × 10 ³ m ² or less.

(11) It contains a fibrous material containing SiO ₂ and is added to concrete so that the total surface area of the fibrous material contained per 1 m ^{3 of the} concrete is 2 × 10 ³ m ² or less. A concrete reinforcing agent for use so that the bending strength measured in accordance with R 5201 is 1.05 times or more the bending strength of concrete of the same component but not containing the fibrous substance.

(12) A fibrous material containing SiO ₂ is included, and the total surface area of the fibrous material contained per 1 m ^{3 of the} mortar is 1 × 10 ⁻² m ² or more and 2 × 10 ³ m ² or less with respect to the mortar. A mortar fluidity improver to be added and used.

(13) The fibrous material containing a fibrous material containing SiO ₂ , wherein the fibrous material content is 0.0001% by mass or more with respect to the total amount of the mortar, and the mortar is contained per 1 m ^{3 of the} mortar. A mortar fluidity improver for use by adding so that the total surface area of the substances is 2 × 10 ³ m ² or less.

(14) A mortar containing water, cement, and a fibrous material containing SiO ₂ , wherein the total surface area of the fibrous material contained per 1 m ^{3 of the} mortar is 1 × 10 ⁻² m ² or more 2 Mortar which is × 10 ³ m ² or less.

(15) A mortar containing water, cement, and a fibrous material containing SiO ₂ ,
The content of the fibrous material, wherein it is the total amount of mortar 0.0001 mass% or more, the sum of the surface area of the fibrous material contained per the mortar 1 m ³ is a ² × 10 ³ m 2 or less ,mortar.

  (16) A method for producing fiber-reinforced concrete, wherein the mortar according to (14) or (15) is cured.

  According to the present invention, fiber reinforced concrete having high mechanical strength and good workability and mortar as a raw material thereof can be provided.

It is a ratio (mass%) plot of bending strength (sigma) _b (N / mm < ² >) of a concrete test piece of Example 1 and Comparative Example 1 versus fibrous substance. It is a ratio (mass%) plot of the compressive strength (N / mm < ² >) of the concrete test piece of Example 1 and Comparative Example 1 vs. fibrous substance. It is a ratio (mass%) plot of the flow value (cm) of the mortar of Example 1 and Comparative Examples 1 and 2 versus the fibrous substance.

  Hereinafter, specific embodiments of the present invention will be described, but the present invention is not limited to the following embodiments, and may be implemented with appropriate modifications within a scope not changing the gist of the present invention. it can.

  In the present specification, “mortar” refers to an uncured mixture containing at least cement and water, which can be used as a raw material for “concrete” or “fiber reinforced concrete”. Further, “concrete” and “fiber reinforced concrete” refer to a mixture in which “mortar” is cured.

<Fiber reinforced concrete of the first aspect>
The fiber reinforced concrete according to the present invention includes a fibrous substance containing SiO ₂ , and the total surface area of the fibrous substance contained per 1 m ^{3 of} the fiber reinforced concrete is 1 × 10 ⁻² m ² or more and 2 × 10. ³ m ² or less.

Such a fiber reinforced concrete has a higher mechanical strength and a fluidity equal to or higher than that of a concrete to which no fibrous substance is added, compared to a concrete to which no fibrous substance is added. When concrete fibrous material is added, the fibrous material, because it contains SiO _2, a high affinity for concrete whose main component is SiO _2, a high dispersibility. A high-strength phase different from ordinary concrete is formed around the fibrous material thus dispersed in the concrete. The presence of such layers in a distributed manner increases the strength of the concrete as a whole. Further, as described above, since the affinity between SiO ₂ and mortar is high and the contact area is small, the fluidity does not decrease. Furthermore, it has been surprisingly found that the fluidity of the mortar improves rather than adding a certain amount of the fibrous material as described above. Such a phenomenon was not seen in normal fiber reinforced concrete.

  In the present specification, the “surface area” means a value measured with an industrial microscope BXFM manufactured by Olympus. Here, the “surface area” is a set of regions (contact regions) where the fibers and the coated fibers are in contact with the concrete. A portion of the concrete containing the fiber is cut, and the area where the concrete is in contact with the fiber seen on the cut surface and the coated fiber is observed with the microscope, and the contact area is measured. Observe a plurality of cut surfaces of the concrete for which the surface area of the contained fibers is to be determined, and measure each of the areas where the fibers and the coated fibers are in contact with the concrete from the microscopic observation of the cut surfaces. Aggregate with insertion, and the total surface area of the fibers contained in the target concrete.

(Fibrous material)
The fibrous substance is not particularly limited as long as it contains SiO ₂ . It may be composed only of SiO _{2 and} may contain other components.

In one embodiment, when the fibrous material includes components other than SiO ₂ , the metal elements that can be included in the fibrous material include aluminum, iron, magnesium, calcium, sodium, titanium, potassium, lithium, scandium, manganese, and cobalt. It is preferable that nickel, zinc, etc. are included. Although the state of these metal elements is not particularly limited, it is preferably present at least in an oxide state, and an atomic ratio of 80% or more, 85% or more, 90% or more, 95% or more of the metal element is an oxide. It is more preferable that it exists in the state. The presence of the metal element in an oxide state can increase the mechanical or thermal strength. In addition, the oxide generally has an advantage that it can be easily obtained by using a mineral as a raw material or oxidizing a metal or a metal salt by heating or the like. Here, the term “metal element” means that the element on the left side of the line connecting boron and astatine in the long-period element periodic table is a metal element. Specifically, since the line connecting boron and astatine passes through B, Si, As, Te, and At, up to Al (aluminum) in the third period, up to Ge (germanium) in the fourth period, An element up to Sb (antimony) in the fifth period and up to Po (polonium) in the sixth period.

In one embodiment, when the fibrous material includes a component other than SiO ₂ , nonmetallic elements that can be included in the fibrous material can include boron, carbon, nitrogen, fluorine, phosphorus, sulfur, and chlorine.

In one embodiment, the content of SiO ₂ is, for example, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more with respect to the total amount of the fibrous material. 35 mass% or more, 40 mass% or more, 45 mass% or more, 50 mass% or more, 55 mass% or more, 60 mass% or more, 65 mass% or more, 70 mass% or more, 75 mass% or more, 80 mass% or more 85 mass% or more, 90 mass% or more, or 95 mass% or more. However, the content of SiO _2, may be less than 5% by weight relative to the total amount of fibrous material. On the other hand, the content of SiO ₂ contained in the radiation shielding agents, relative to the total amount of fibrous material, 95 wt% or less, 90 wt% or less, 85 wt% or less, 80 wt% or less, 75 wt% or less, 70% or less, 65% or less, 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, It may be 20% by mass or less, 15% by mass or less, and 10% by mass or less. However, the content of SiO ₂ may be more than 95% by mass with respect to the total amount of the fibrous material. In the present specification, the amounts of various elements refer to the amounts of elements measured with an energy dispersive X-ray microanalyzer using a scanning electron microscope JSM-5600 manufactured by JEOL at room temperature. .

In one embodiment, the content of SiO ₂ is preferably 30% by mass or more, more preferably 35% by mass or more, and more preferably 40% by mass or more with respect to the total amount of the fibrous material. Further preferred. When the content of SiO ₂ is more than the required amount, the lightness and flexibility of the fibers can be increased, and the lightness and toughness of the concrete can be improved. On the other hand, the upper limit of the content of SiO ₂ contained in the fibrous material is preferably 70% by mass or less, more preferably 65% by mass or less, and further preferably 60% by mass or less. preferable.

In one embodiment, the content of the metal element is, for example, 1% by mass or more, 2% by mass or more, 5% by mass or more, 7% by mass or more, 10% by mass or more, 15% by mass or more with respect to the total amount of the fibrous material. 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, 45% by mass or more, 50% by mass or more, 55% by mass or more, 60% by mass or more, 65% by mass or more 70 mass% or more, 75 mass% or more, 80 mass% or more, 85 mass% or more, 90 mass% or more, or 95 mass% or more. However, the content of SiO ₂ may be less than 1% by mass with respect to the total amount of the fibrous material. On the other hand, the content of SiO ₂ contained in the fibrous material is 95% by mass or less, 90% by mass or less, 85% by mass or less, 80% by mass or less, 75% by mass or less, based on the total amount of the fibrous material. 70% or less, 65% or less, 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, It may be 20% by mass or less, 15% by mass or less, 10% by mass or less, 7% by mass or less, 5% by mass or less, 2% by mass or less, and 1% by mass or less. However, the content of the metal element may be more than 95% by mass with respect to the total amount of the fibrous material.

  In one embodiment, the total amount of the metal element is preferably 10% by mass or more, more preferably 12% by mass or more, and 15% by mass or more with respect to the total amount of the fibrous substance. More preferably, it is particularly preferably 17% by mass or more. When the content of the metal element is not less than the required amount, the strength of the fiber can be increased. On the other hand, the content of the metal element contained in the fibrous material is preferably 45% by mass or less, more preferably 42% by mass or less, still more preferably 40% by mass or less, and 38 It is particularly preferable that the content is not more than mass%. When the content of all metal elements is not more than the required amount, the fiber reinforced concrete can be further reduced in weight. In addition, the processability of the fibrous material can be improved.

As the fibrous material, either an artificial product or a natural product can be used. In one embodiment, it is preferable to use a mineral as the fibrous material from the viewpoint of economy. As minerals, for example, igneous rocks, sedimentary rocks, and metamorphic rocks can be used. Since igneous rocks contain SiO ₂ , they can be used as they are as raw materials for fibers. In addition, igneous rocks have an advantage from an economical point of view because they have a large amount of mining. As the igneous rock, for example, peridotite, gabbro, diorite, granodiorite, granite, kimberly rock, basalt, andesite, dacite, rhyolite can be used. Among these, it is more preferable to use basalt.

Basalt is a kind of igneous rocks as described above, in which the content of SiO ₂ has a patchy tissue 45-52 wt%. Basalt is a mineral that includes pyroxene, olivine, plagioclase, etc., and is the rock most commonly found on the earth's surface. Therefore, by using basalt, there is an advantage that an increase in the raw material cost of the fibrous substance and an adverse effect on the environment due to mass production and mining can be suppressed. Basalt also has the advantage of being easily fiberized and is commercially available as basalt fiber.

Basalts are classified into alkali basalts, flood basalts, ocean island basalts, deep sea basalts, island arc basalts, etc., depending on the location where they are mined. Mainly oxides of iron, magnesium and calcium. Specifically, the composition of the basalt is roughly 40 to 60% by mass of silicon oxide, 10 to 20% by mass of aluminum oxide, 5 to 15% by mass of iron oxide (total of FeO and Fe ₂ O ₃ ), 1 to 1 of magnesium oxide. 15% by mass, calcium oxide 5-15% by mass, titanium oxide 0-5% by mass, manganese oxide 0-5% by mass, sodium oxide 0-5% by mass, potassium oxide 0-3% by mass, diphosphorus pentoxide 0-0 About 1% by mass.

  In one embodiment, the fiber diameter of the fibrous material (fiber diameter) is, for example, 6 μm or more, 8 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, 35 μm or more, 40 μm or more, 45 μm or more, 50 μm. As described above, it may be 60 μm or more, 70 μm or more, 80 μm or more, 90 μm or more, 100 μm or more, 200 μm or more, 500 μm or more, 1 mm or more, 2 mm or more, 5 mm or more, 10 mm or more. However, the fiber diameter may be less than 6 μm. When the fiber diameter is equal to or larger than the required amount, the strength of the fiber can be further increased and the toughness of the concrete can be increased. On the other hand, the fiber diameter is, for example, 20 mm or less, 10 mm or less, 5 mm or less, 2 mm or less, 1 mm or less, 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, 150 μm or less, 120 μm or less, 100 μm or less, 80 μm or less, 50 μm or less. It may be. However, the fiber diameter may be more than 20 mm. When the fiber diameter is less than the required amount, the flexibility of the fiber can be further increased and the toughness of the concrete can be increased. The “fiber diameter” means the diameter when the cross section perpendicular to the fiber axis direction is circular, and when not, the straight line extending from the center of gravity of the cross section perpendicular to the fiber axis direction to both ends of the cross section. The longest of them.

  In one embodiment, the fiber length of the fibrous substance (fiber length) is, for example, 20 μm or more, 50 μm or more, 100 μm or more, 200 μm or more, 500 μm or more, 1 mm or more, 2 mm or more, 5 mm or more, 10 mm or more, 20 mm or more, It may be 50 mm or more, 100 mm or more, 200 mm or more, 500 mm or more, 1000 mm or more, 2000 mm or more, 5000 mm or more, 10,000 mm or more. However, the fiber length may be less than 0.1 mm. When the fiber length is not less than the required amount, the strength of the fiber can be increased and the toughness of the concrete can be further increased. On the other hand, the fiber length is 20000 mm or less, 10,000 mm or less, 5000 mm or less, 2000 mm or less, 1000 mm or less, 500 mm or less, 200 mm or less, 100 mm or less, 50 mm or less, 20 mm or less, 10 mm or less, 5 mm or less, 2 mm or less, 1 mm or less, It may be 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, or 50 μm or less. However, the fiber length may be more than 1000 mm. When the fiber diameter is equal to or less than the required amount, handling of mortar mixing can be improved.

In one embodiment, the density of the fibrous material is, for example, 1.0 g / cm ³ or more, 1.1 g / cm ³ or more, 1.2 g / cm ³ or more, 1.3 g / cm ³ or more, 1.4 g / preferably cm ³ or more, 1.5 g / cm ³ or more, 1.7 g / cm ³ or more, 2.0 g / cm ³ or more, and more preferably 2.1 g / cm ³ or more. However, the density may be less than 1.0 g / cm ³ . When the density is equal to or higher than the required amount, the density is close to that of concrete, so that dispersibility can be improved, and strength and workability can be improved. On the other hand, the density is preferably, for example, 5.0 g / cm ³ or less, 4.5 g / cm ³ or less, 4 g / cm ³ or less, and 3.5 g / cm ³ or less, 3.2 g / cm ^3. Hereinafter, it is more preferably 3.0 g / cm ³ or less, and further preferably 2.7 g / cm ³ or less, 2.6 g / cm ³ or less, or 2.5 g / cm ³ or less. However, the density may be more than 5.0 g / cm ³ . When the density is equal to or less than the required amount, the density becomes close to the density of concrete, the fibrous dispersibility can be improved, the strength and workability can be improved, and the lightweight property of the concrete can be ensured.

The content of the fibrous substance is not particularly limited, and may be 1 per 1 m ^{3 of} fiber reinforced concrete or 2 or more. When one fibrous substance is present in a plurality of 1 m ³ units of fiber reinforced concrete, the average number per 1 m ^{3 of} fiber reinforced concrete may be more than 0 and less than 1.

In one embodiment, the surface area of the fibrous material is, for example, 2 × 10 ⁻⁹ m ² / g or more, 5 × 10 ⁻⁹ m ² / g or more, and 1 × 10 ⁻⁸ m ² / g or more. Preferably, it is 7 × 10 ⁻⁸ m ² / g or more, 5 × 10 ⁻⁷ m ² / g or more, 2 × 10 ⁻⁷ m ² / g or more, and 1 × 10 ⁻⁷ m ² / g or more. preferable. When the surface area is greater than or equal to the required amount, the strength of the fibers can be further increased and the toughness of the concrete can be increased. However, the surface area of the fibrous substance may be, for example, less than 2 × 10 ⁻⁹ m ² / g. On the other hand, the surface area of the fibrous material is preferably 2 × 10 ⁻³ m ² / g or less, 1 × 10 ⁻³ m ² / g or less, or 7 × 10 ⁻⁴ m ² / g or less, for example. 5 × 10 ⁻⁴ m ² / g or less, 2 × 10 ⁻⁴ m ² / g or less, more preferably 1 × 10 ⁻⁴ m ² / g or less, and 7 × 10 ⁻⁵ m ² / g or less. More preferably, it is 5 × 10 ⁻⁵ m ² / g or less, and 2 × 10 ⁻⁵ m ² / g or less. When the surface area is less than the required amount, the fluidity of the mortar can be further improved.

In one embodiment, as described above, the fibrous material is a bundle as long as the total surface area of the fibrous material contained per 1 m ^{3 of} fiber reinforced concrete is 2 × 10 ³ m ² or less. It can also be used. In this case, as the surface area, the surface area of the bundle is used for calculating the total surface area.

  In one embodiment, when the fibrous substance is a bundle, the fibrous substance includes a binder resin, a binder bonded by a coupling agent, a twisted fiber by twisting a fiber, and a lubricant applied. It is preferable to use it. By using the fibrous material as a bundle, the surface area of the fibrous material can be reduced as a whole while maintaining the flexibility of the fiber because the fibers are thin, and as a result, during concrete construction Fluidity can be secured. As the binder resin, acrylic resin, vinyl acetate resin, epoxy resin, urethane resin, glyoxal resin, phenol resin, butadiene resin, methacrylic resin, or the like can be used. As the coupling agent, acrylic cyan, aminosilane, or the like can be used. Furthermore, an ammonium salt or the like can be used as the lubricant.

  In one embodiment, the content of the fibrous substance is, for example, 0.0001% by mass or more, 0.0002% by mass or more, 0.0005% by mass or more, 0.001% by mass or more, based on the total amount of fiber reinforced concrete, 0.002 mass% or more, 0.005 mass% or more, 0.01 mass% or more, 0.02 mass% or more, 0.05 mass% or more, 0.10 mass% or more, 0.11 mass% or more, 0 .12% by mass or more, 0.13% by mass or more, 0.14% by mass or more, 0.15% by mass or more, 0.16% by mass or more, 0.17% by mass or more, 0.18% by mass or more, 19% by mass or more, 0.20% by mass or more, 0.22% by mass or more, 0.24% by mass or more, 0.26% by mass or more, 0.28% by mass or more, 0.30% by mass or more, 0.32% % By mass or more, 0.34% by mass or more, 0.36% by mass or more, 0 38 mass% or more, 0.40 mass% or more, 0.42 mass% or more, 0.44 mass% or more, 0.46 mass% or more, 0.48 mass% or more, 0.50 mass% or more, 0.55 It may be at least mass%, at least 0.60 mass%, at least 0.65 mass%, at least 0.70 mass%, at least 0.75 mass%, at least 0.80 mass%. However, the content of the fibrous substance may be less than 0.0001% by mass with respect to the total amount of the fiber reinforced concrete. When the fiber reinforced concrete according to the present invention is added even in a minute amount, the bending strength is improved. Moreover, the fluidity | liquidity of the mortar which is a raw material of fiber reinforced concrete can be surprisingly added by adding 0.15 mass% or more. Moreover, as content of a fibrous substance, 20 mass% or less, 19 mass% or less, 18 mass% or less, 17 mass% or less, 16 mass% or less, 15 mass% or less, 14 mass% with respect to the total amount of fiber reinforced concrete. % Or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less % Or less, 3 mass% or less, 2 mass% or less, and 1 mass% or less. However, the content of the fibrous substance may be more than 20% by mass with respect to the total amount of the fiber reinforced concrete.

As described above, in the fiber reinforced concrete according to the present invention, the total surface area of the fibrous materials contained per 1 m ³ is 1 × 10 ⁵ m ² or less. Generally, fibrous materials are as thin as possible (smaller in diameter), and the shorter the length, the higher the dispersibility in concrete. Therefore, the surface area of the fibrous material contained in 1 m ^{3 of} fiber-reinforced concrete is reduced. The total tends to be large.

On the other hand, according to the knowledge of the present inventors, the problem of fluidity drop that occurs in the conventional fiber reinforced concrete by rather reducing the sum of the specific surface areas of the fibrous materials contained per 1 m ³ of fiber reinforced concrete. It has been found that can be solved. In addition, by fibrous material containing SiO _2, increase the affinity of the SiO ₂ is a main component of the mortar and a density of equal, by increasing the dispersibility was also found to be able to maintain fluidity.

In one embodiment, the total surface area of the fibrous material contained per 1 m ³ of the fiber reinforced concrete is 2 × 10 ³ m ² or less, 1 × 10 ³ m ² or less, 7 × 10 ² m ² or less, 5 × 10 ² m ² or less, 2 × 10 ² m ² or less, 1 × 10 ² m ² or less, 7 × 10 m ² or less, 5 × 10 m ² or less, 2 × 10 m ² or less, 1 × 10 m ² or less Is preferred. The total surface area is 1 × 10 ⁻² m ² or more, 7 × 10 ⁻¹ m ² or more, 5 × 10 ⁻¹ m ² or more, 2 × 10 ⁻¹ m ² or more, 1 × 10 ⁻¹ m. It may be ² or more.

  According to the fibrous material as described above, the toughness of concrete, particularly the bending strength, can be increased, and the fluidity of mortar can be improved. That is, the fibrous substance as described above can be used as a concrete reinforcing agent or a mortar fluidity improver.

(Other ingredients)
The concrete of the present invention comprises at least cement and water in addition to the fibrous material as described above. Further, depending on the use, coarse aggregates, fine aggregates, admixtures and the like used for civil engineering or construction can be included.

  The fiber reinforced concrete of the present invention can contain any components as long as the effects of the present invention are not impaired. As such components, thickeners, fluidizers, water reducing agents, dispersants, high performance water reducing agents, high performance AE water reducing agents, AE water reducing agents, AE agents, all of which can be contained in mortar and concrete, Fast curing agent, setting accelerator, setting retarder, pozzolanic reactive material, drying shrinkage reducing agent, expansion agent, foaming agent, defoaming agent, re-emulsifying powder resin, polymer dispersion, water repellent, extender Etc. In particular, for example, when kneading, it is preferable to use a thickener from the viewpoint of more reliably preventing material separation. As the thickener, when accompanied by long-distance pumping of fresh concrete, it is preferable to use one having thixotropy with respect to change in viscosity. In addition, when short fibers are used more frequently, it is preferable to use a water reducing agent together in order to assist the dispersibility.

  In the mortar which is the raw material of the conventional fiber reinforced concrete, as described above, the fluidity is lowered by adding the fibrous substance. In such a case, for example, it is generally performed to improve the operability of kneading mortar by adding a fluidizing agent. On the other hand, in the mortar which is the raw material of the fiber reinforced concrete of the present invention, the fluidity can be prevented from lowering by adding the specific fibrous substance described above. Therefore, the amount of the fluidizing agent other than the specific fibrous material described above is, for example, 5% by mass or less, 2% by mass or less, 1% by mass or less, and 0.5% by mass or less with respect to the total amount of the fiber reinforced concrete. 0.2 mass%, 0.1 mass% or less, 0.05 mass% or less, 0.02 mass% or less, 0.01 mass% or less, 0.005 mass% or less, 0.002 mass% or less, 0 .001% by mass or less, 0.0005% by mass or less, 0.0002% by mass or less, and 0.0001% by mass or less, which may be a small amount compared to conventional fiber reinforced concrete. Moreover, as addition amount of superplasticizers other than the specific fibrous substance mentioned above, it may be 0 mass% or more, 0.00001 mass% or more, and 0.00002 mass% or more.

  The bending strength of fiber reinforced concrete is 1.05 or more, 1.1 or more, 1.2 or more, 1.3 or more, or more than the bending strength of concrete of the same component, although it does not contain fibrous materials. 4 times or more, 1.5 times or more, 1.6 times or more, 1.7 times or more, 1.8 times or more, 1.9 times or more, 2.0 times or more, 2.2 times or more, 2.4 times As described above, it may be 2.6 times or more, 2.8 times or more, 3.0 times or more, 3.5 times or more, 4 times or more. In addition, "bending strength" means the value measured based on JISR5201.

  The fiber reinforced concrete as described above has high strength and excellent workability. In terms of strength, it can surprisingly have, for example, 4 to 5 times the bending strength compared to conventional concrete with no added fibrous material. This can make concrete the thickness of the conventional 1 / 4-1 / 5, and can use it, and even if it adds the cost of a fibrous material, it can fully reduce a cost.

(Mortar of the first aspect)
The mortar according to the present invention is a mortar containing water, cement, and a fibrous material containing SiO _2, and the total surface area of the fibrous material contained per 1 m ^{3 of} the mortar is 1 × 10 ⁻² m ^2. The above is 2 × 10 ³ m ² or less. By effecting such a mortar, the fiber-reinforced concrete of the first aspect described above can be produced.

  The content of water in the mortar is not particularly limited, and may be, for example, 30% by mass or more, 35% by mass or more, 40% by mass or more, and 45% by mass or more. Moreover, as content of water, it may be 75 mass% or less, 70 mass% or less, 65 mass% or less, and 60 mass% or less, for example.

  In addition, as a fibrous substance, cement, and other components contained in this mortar, the thing similar to the fiber reinforced concrete of a 1st aspect can be used by the same usage-amount. It should be noted that, by curing the mortar, water evaporates very slightly, but this does not affect the range of usage.

  As the flow value of the mortar, it does not contain fibrous substances, but the bending strength of the mortar of the same component is 0.90 times or more, 0.92 times or more, 0.95 times or more, 0.97 times or more, 1 time or more, 1.02 times or more, 1.05 times or more, 1.07 times or more, 1.1 times or more, 1.12 times or more, 1.15 times or more, 1.17 times or more, 1.20 times or more It may be 22 times or more, 1.25 times or more, 1.27 times or more, or 1.30 times or more. The “flow value” refers to a value measured according to JIS R 5201. This flow value is used as an indicator of fluidity.

(Production method)
In the method for producing fiber-reinforced concrete according to the present invention, at least water, cement, and a fibrous substance containing SiO ₂ , the total surface area of fibrous substances contained per 1 m ^{3 of} mortar obtained is 1 × 10. ^-2 m ² or more and 2 × 10 ³ m ² or less is kneaded to obtain a mortar, and then the mortar is cured.

There are no particular limitations on the raw material kneading method, the mortar curing method, and the equipment used therefor as long as it is a conventional method in the field of civil engineering and construction.

<Fiber reinforced concrete of the second aspect>
The fiber reinforced concrete according to the present invention includes a fibrous material containing SiO ₂ , the content of the fibrous material is 0.0001% by mass or more based on the total amount of the fiber reinforced concrete, and the fiber reinforced concrete is 1 m. The sum total of the surface areas of the fibrous substances contained in ³ is 2 × 10 ³ m ² or less.

  According to such a fiber reinforced concrete, in the same manner as the fiber reinforced concrete of the first aspect, the mechanical strength is higher than that of the concrete to which no fibrous substance is added, and the flow of the mortar as the raw material is increased. The property is equal to or higher than that of concrete to which no fibrous substance is added.

Also in the mortar which is the raw material of such fiber reinforced concrete, the content of the fibrous substance and the total surface area of the fibrous substance are the same as those of the fiber reinforced concrete of the second aspect described above.

  In addition, in the fiber reinforced concrete according to the second aspect and the mortar as a raw material thereof, other characteristics relating to the fibrous material, other components and the production method other than the total content of the fibrous material and the surface area of the fibrous material are as follows: It is the same as the characteristic of the fiber reinforced concrete of the 1st aspect mentioned above.

<Fiber-reinforced concrete of the third aspect>
The fiber reinforced concrete according to the present invention contains a fibrous material containing SiO ₂ , and the total surface area of the fibrous material contained per 1 m ^{3 of} fiber reinforced concrete is 2 × 10 ³ m ² or less, and JIS The bending strength measured in accordance with R 5201 is 1.05 times or more the bending strength of the concrete of the same component although not including the fibrous material.

  According to such a fiber reinforced concrete, it has high mechanical strength compared with the concrete which does not add a fibrous substance like the fiber reinforced concrete of the 1st aspect, and is the raw material. The fluidity of the mortar is equal to or higher than that of the concrete to which no fibrous substance is added.

  In addition, in the fiber reinforced concrete according to the third aspect and the mortar that is the raw material thereof, other characteristics relating to the fibrous material, other components, and the manufacturing method other than the content of the fibrous material and the bending strength of the fiber reinforced concrete are described above. This is the same as the characteristics of the fiber-reinforced concrete of the first aspect.

  EXAMPLES Hereinafter, although the Example of this invention is shown and this invention is demonstrated further in detail, this invention is not limited to this Example at all.

<Production of concrete specimen>
Concrete test pieces of Example 1 and Comparative Examples 1 and 2 were prepared according to the following procedure.

Example 1
At room temperature, 850 g of cement, 450 g of water, and basalt fiber (basalt fiber) twisted yarn (about 1500 fibers with a fiber diameter of 12 μm are bundled and twisted to form a twisted yarn having a diameter of 1 mm and a length of 12 mm. ), Fine aggregate, fly ash and water reducing material were mixed and kneaded in a stainless steel container at 150 rpm for 5 minutes using a mortar mixer to obtain a slurry mortar. Next, the mortar was cured by drying and curing, and a concrete specimen having a size of 40 mm × 40 mm × 160 mm was obtained using a specimen mold.

Here, 13 g of twisted yarn of basalt fiber (the amount of twisted yarn with respect to the total amount of mortar (hereinafter also referred to as “ratio of fibrous substance”) 0.5 mass%), 20 g (ratio of fibrous substance 0.75 mass) %) And 26 g (fibrous substance ratio 1 mass%). Incidentally, of these samples, the surface area of the fibrous material contained per fiber reinforced concrete 1 m ³ sum, each 6.4 m ^2, 9.5 m ^2, a 12.7 m ^2.

(Comparative Example 1)
A concrete test piece was obtained in the same manner as in Example 1 except that the twisted basalt fiber was not added.

(Comparative Example 2)
A concrete test piece was obtained in the same manner as in Example 1 except that carbon fiber fibers having a fiber diameter of 5 μm were used instead of the basalt fiber twist. Incidentally, the sum of the surface area of the fibrous material contained per fiber reinforced concrete 1 m ^3, respectively ^{5.0 × 10 3 m 2, 7.5} × 10 3 m 2, a 1.0 × ¹⁰ 4 ^{m 2.}

<Evaluation of concrete specimen>
According to the following procedures, the bending strength, flow value and compressive strength of the concrete test pieces of Example 1 and Comparative Examples 1 and 2 were measured and evaluated.

(Bending strength test)
The bending strength was measured according to JIS R 5201. FIG. 1 is a plot of the bending strength σ _b (N / mm ² ) of the concrete test pieces of Example 1 and Comparative Example 1 versus the ratio (mass%) of the fibrous material. In addition, since the fibrous substance is not added in the comparative example 1, in FIG. 1, for the sake of convenience, regardless of the ratio of the fibrous substance on the horizontal axis, no addition (the ratio of the fibrous substance is 0% by mass). Values are listed.

  As can be seen from FIG. 1, the concrete test piece of Example 1 to which a specific fibrous material was added showed higher bending strength than the concrete test piece of Comparative Example 1 to which no fibrous material was added. It has also been found that the increase in flexural strength increases with the proportion of fibrous material.

(Compressive strength test)
The compressive strength was measured according to JIS R 5201. FIG. 2 is a plot of the compressive strength (N / mm ² ) of the concrete test pieces of Example 1 and Comparative Example 1 versus the ratio (mass%) of the fibrous material. In addition, since the fibrous substance is not added in the comparative example 1, in FIG. 2, for the sake of convenience, regardless of the ratio of the fibrous substance on the horizontal axis, no addition (the ratio of the fibrous substance is 0% by mass). Values are listed.

  As can be seen from FIG. 2, the concrete test piece of Example 1 to which a specific fibrous material was added had no significant change in compressive strength compared to the concrete test piece of Comparative Example 1 to which no fibrous material was added. It was.

(Flow value test)
The flow value was measured according to JIS R 5201. FIG. 3 is a plot of the flow value (cm) of the mortar of Example 1 and Comparative Examples 1 and 2 versus the ratio (mass%) of the fibrous material. In addition, since the fibrous substance is not added in the comparative example 1, in FIG. 3, for the sake of convenience, regardless of the ratio of the fibrous substance on the horizontal axis, no addition (the ratio of the fibrous substance is 0% by mass). Values are listed.

  As can be seen from FIG. 3, in the mortar of Example 1 to which a specific fibrous material was added, when the fibrous material was low, specifically, less than 0.15% by mass, the concrete fibrous material was not added. It was the same as the mortar of Comparative Example 1, and no decrease in fluidity due to the addition of fibrous material was observed. When it exceeded 0.15% by mass, the flow value was surprisingly higher than that of the mortar of Comparative Example 1 to which no concrete fibrous material was added. On the other hand, in the mortar of the comparative example 2, it turned out that the flow value decreases compared with the mortar of the comparative example 1 to which the ratio of the fibrous substance increases and the concrete fibrous substance is not added. As can be seen from the above, the flow value can be prevented from being lowered by adding a specific fibrous substance, and the flow value can be improved by adding a specific amount or more.

Claims (16)

A fiber reinforced concrete containing a fibrous material containing SiO ₂ ,
The fiber-reinforced sum of the surface area of the fibrous material contained per concrete 1 m ³ is ² × ¹⁰ 3 ^m 2 or less 1 × ¹⁰ -2 ^{m 2} or more, the fiber-reinforced concrete. A fiber reinforced concrete containing a fibrous material containing SiO ₂ ,
The content of the fibrous substance is 0.0001% by mass or more based on the total amount of the fiber reinforced concrete,
Fiber reinforced concrete in which the total surface area of the fibrous substances contained per 1 m ^{3 of the} fiber reinforced concrete is 2 × 10 ³ m ² or less. A fiber reinforced concrete containing a fibrous material containing SiO ₂ ,
The sum total of the surface areas of the fibrous substances contained per 1 m ^{3 of the} fiber reinforced concrete is 2 × 10 ³ m ² or less,
A fiber reinforced concrete having a flexural strength measured in accordance with JIS R 5201 of 1.05 times or more of a flexural strength of concrete of the same component but not including the fibrous material.   The fiber-reinforced concrete according to any one of claims 1 to 3, wherein the fibrous substance has a diameter of 6 µm or more.   The fiber reinforced concrete according to any one of claims 1 to 4, wherein the fibrous substance is a bundle.   The fiber-reinforced concrete according to any one of claims 1 to 5, wherein a content of the fibrous substance is 10% by mass or less.   The fiber-reinforced concrete according to any one of claims 1 to 5, wherein a content of the fibrous substance is 1% by mass or less.   The fiber reinforced concrete according to any one of claims 1 to 7, wherein the fibrous substance is a basalt fiber. Comprising a fibrous material comprising SiO ₂ ;
A concrete reinforcing agent for use by adding to the concrete such that the total surface area of the fibrous substances contained per 1 m ^{3 of the} concrete is 1 × 10 ⁻² m ² or more and 2 × 10 ³ m ² or less. . Comprising a fibrous material comprising SiO ₂ ;
With respect to the concrete, the content of the fibrous material is 0.0001% by mass or more with respect to the total amount of the concrete, and the total surface area of the fibrous material contained per 1 m ^{3 of the} concrete is 2 × 10 ³ m ² or less. Concrete reinforcing agent to be added and used. Comprising a fibrous material comprising SiO ₂ ;
The bending strength measured according to JIS R 5201 is added to the concrete so that the total surface area of the fibrous material contained per 1 m ^{3 of the} concrete is 2 × 10 ³ m ² or less. A concrete reinforcing agent for use so as to be 1.05 times or more of the bending strength of concrete having the same component but not containing a fibrous substance. Comprising a fibrous material comprising SiO ₂ ;
Flow of mortar for use by adding to the mortar such that the total surface area of the fibrous material contained per 1 m ^{3 of the} mortar is 1 × 10 ⁻² m ² or more and 2 × 10 ³ m ² or less. Improver. Comprising a fibrous material comprising SiO ₂ ;
The content of the fibrous substance with respect to the mortar is 0.0001% by mass or more with respect to the total amount of the mortar, and the total surface area of the fibrous substance contained per 1 m ^{3 of the} mortar is 2 × 10 ³ m ² or less. A mortar fluidity improver to be added and used. A mortar containing water, cement, and a fibrous material containing SiO ₂ ,
The sum of the surface area of the fibrous material contained per mortar 1 m ³ is ² × ¹⁰ 3 ^m 2 or less 1 × ¹⁰ -2 ^{m 2} or more, mortar. A mortar containing water, cement, and a fibrous material containing SiO ₂ ,
The content of the fibrous substance is 0.0001% by mass or more based on the total amount of the mortar,
The sum of the surface area of the fibrous material contained per mortar 1 m ³ is ² × ¹⁰ 3 ^m 2 or less, mortar.   The manufacturing method of fiber reinforced concrete which hardens the mortar of Claim 14 or 15.

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