JP2001316157A - Hydraulic composition and fiber-reinforced cured body using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber-reinforced hydraulic hardened body with toughness and aseismaticity and a hydraulic composition for forming the hardened body and a method for on-site application using the composition. SOLUTION: The composition contains a hydraulic material consisting of one or more kinds of materials selected from a cement as a main component, a silica fume, a blast furnace slag and a fly ash, a reinforcing fiber, an aggregate and water. Thickness of the fiber X, content of the hydraulic material C, content of the aggregate S and content of water are 55-270 dtex, 750-1300 kg/m3, 400-1100 kg/m3 and 270-420 kg/m3, respectively. The following formula (I) and (ID are satisfied in the composition: 2.625-0.0075.X<=Y<=3.375-0.0075.X... (I) 47.Y+253<=W<=47.Y+293... (II) (wherein, Y=C/S).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydraulic material composition capable of providing a cured product having high fluidity and excellent toughness and bending strength.
Further, the present invention relates to a fiber-reinforced hydraulically cured product obtained from the hydraulic material composition, and further to a method of performing on-site construction using the composition.

[0002]

2. Description of the Related Art Conventionally, hydraulic materials such as cement and gypsum have low tensile strength and are fragile, and thus have been reinforced with reinforcing fibers such as metal fibers, rock fibers, glass fibers, and organic fibers. . Blending strength and the like of the cured product can be improved by blending such fibers. However, blending of fine fibers reduces the fluidity of the paste and causes material separation, and also causes problems such as fiber balls and flocs. there were. Therefore, the workability is low and on-site construction is difficult,
In addition, if the dispersion state of the fibers is insufficient, the bending strength and the like of the obtained hydraulically cured product decrease.

[0003]

From the above, it can be seen that large-diameter fibers having excellent dispersibility (for example, 1000 to 6000 dt) are used.
ex: about 0.15 to 0.8 mm in diameter) is also considered, but the larger the diameter, the more difficult it is to exert the strength of the fiber, so the bending strength and toughness of the cured product cannot be sufficiently improved. There was a problem. An object of the present invention is to provide a hydraulic material composition having a high fluidity and capable of sufficiently exhibiting a fiber reinforcing effect, and a hydraulic cured product obtained from the composition, and further comprising using the composition. It is to propose a method for performing on-site construction efficiently.

[0004]

SUMMARY OF THE INVENTION The present invention provides (1) a hydraulic material and a reinforcing fiber comprising at least one material selected from cement, silica fume, blast furnace slag, and fly ash, wherein cement is a main component. , An aggregate and water at least, wherein the reinforcing fibers have a fineness X (dtex) of 55 to 270 dtex and a hydraulic material blending amount C (kg / m ³ ) of 750 to 13
00 kg / m ³ , aggregate content S (kg / m ³ ) is 400-
1100 kg / m ³ , water content W (kg / cm ³ ) is 27
0 to 420 kg / m ³ and the following formulas (I) and (I)
2.625-0.0075 · X ≦ Y ≦ 3.375-0.0075 · X (I) 47 · Y + 253 ≦ W ≦ 47 · Y + 293 (II) (II) , Y is C / S.) (2) The hydraulic material composition according to (1), wherein at least a part of the reinforcing fibers is a polyvinyl alcohol-based fiber.
(3) A fiber-reinforced hydraulic cured product obtained from the hydraulic material composition according to (1) or (2), (4) On-site using the hydraulic material composition according to (1) or (2) Method of construction.

[0005]

In the present invention, the fineness of the reinforcing fibers must be 55 dtex or more from the viewpoint of uniformly dispersing the fibers and obtaining a composition having high fluidity and excellent workability. In general, when fibers having a fineness of about 10 to 20 dtex are used, a water / hydraulic material (mass ratio) ≧ 0.4 is required in order to obtain a hydraulic material composition having a high fluidity of 160 mm or more in a flow test. It is necessary to However, in the present invention, since the dispersibility of the reinforcing fiber is high and the fluidity of the composition is not easily reduced,
Even if the hydraulic material (mass ratio) is further reduced, the same level of fluidity can be secured. When the amount of the water / hydraulic material is reduced, the formation and shrinkage of the cured product are suppressed, and the strength and durability of the cured product are improved. In addition, the workability of the hydraulic material composition is improved, so that the prefabricated material is used. Not only manufacturing but also on-site construction becomes easy. In addition, when a reinforcing fiber having a large fineness is used, it is thought that "penetration" is likely to occur and it is difficult to suppress the expansion of cracks, that is, it is considered that a hardened body having high toughness is difficult to be obtained. By using a specific composition, a cured product excellent not only in bending strength but also in toughness can be obtained even when the fineness is relatively large.

From the viewpoint of the uniform dispersibility of the fibers, it is preferable that the fineness is large. However, if the fineness is too large, it is difficult to sufficiently exert the fiber strength. Furthermore, when cracks occur in the cured product due to external stress, bridging (crosslinking) fibers are more likely to "peel off", and even when a hydraulic composition is used in a specific composition, the bridging fibers suppress crack expansion. It becomes difficult to do. Therefore, in order to obtain a cured product having high toughness by enhancing the bridging effect, the fineness of the reinforcing fiber is set to 270 dtex or less, preferably 250 dte.
x or less. The fiber length of the fiber may be set according to the fineness, the composition of the paste, and the like. From the viewpoint of uniform dispersibility, the fiber length is preferably 100 mm or less, particularly preferably 50 mm or less, and more preferably 40 mm or less, and the bridging effect is effective. In view of the fact that the fiber length is 3 mm or more, particularly 5 mm or more, more preferably 8 mm or more,
It is preferably 0 mm or more.

From the viewpoint of enhancing the reinforcing effect and obtaining a sufficient bridging effect, the strength of the reinforcing fiber is preferably at least 6 cN / dtex, more preferably at least 7 cN / dtex, further preferably at least 8 cN / dtex. By increasing the fiber strength, the bending strength of the cured product can be increased, and the bridging fiber that suppresses crack expansion is less likely to break, so that a cured product with high toughness can be obtained. In addition, since the frictional resistance generated when a stress is applied to the cured body is generated in proportion to the surface area of the fiber, it is preferable that the fiber having a smaller fineness has a higher strength. The upper limit of the fiber strength is not particularly limited, but is generally 100 cN / dtex or less.

[0008] The type of fiber is not particularly limited. For example, polyolefin fiber (polypropylene fiber, polyethylene fiber, etc.), acrylic fiber, polyamide fiber (including aramid fiber), polyester fiber (molten liquid crystalline) Polyester, polyethylene naphthalate, etc.), polybenzoxazole-based fibers, rayon-based fibers (polynosic rayon fibers, solvent-spun rayon fibers, etc.), inorganic fibers (glass fibers, steel fibers, etc.), and polyvinyl alcohol (PVA) -based fibers can be used. . Wood pulp or the like can also be used. However, from the viewpoint of effectively increasing the flexural strength and toughness of the hydraulic hardened body, it is preferable to use at least PVA-based fibers having high mechanical affinity and high affinity with hydraulic materials.
It is more preferable to use mainly A-based fibers. Specifically, it is preferable that 60% by mass or more, particularly 70% by mass or more, further 90% by mass or more of the reinforcing fibers be PVA-based fibers. Note that fibers other than the reinforcing fibers specified in the present invention may be blended as long as the effects of the present invention are not substantially impaired. The amount of the fiber is preferably 0.1% by volume or more, particularly 0.5% by volume or more, more preferably 1% by volume or more from the viewpoint of the reinforcing effect, and 5% by volume or less from the viewpoint of uniform dispersibility. Further, it is preferably at most 4% by volume, more preferably at most 3% by volume.

The use of such fibers can improve the mechanical properties and the like of the cured product, but it is necessary to increase the fluidity and ensure excellent workability, and to further improve the hydraulic strength of the cured product, such as bending strength and toughness. From the point of obtaining the body, it is necessary to use a hydraulic material composition having a specific composition. This will be described in detail below.
First, the hydraulic material used in the present invention is composed of at least one material selected from cement, silica fume, blast furnace slag, and fly ash, and is mainly composed of cement. In order to obtain a cured product having excellent mechanical performance, it is necessary to use cement as a main component. Specifically, portland cement, particularly ordinary portland cement, can be suitably used. Among them, those having a lower C ₃ A (calcium aluminate) content are preferred from the viewpoint of increasing the fluidity of the composition.

In the present invention, it is not necessary to use only cement as the hydraulic material, and a part of the cement may be replaced with at least one material selected from silica fume, blast furnace slag, and fly ash. . In general, C ₃ A contained in cement reduces the fluidity of the composition. However, the amount of C ₃ A can be reduced by blending a pozzolanic substance by reducing the amount of cement to increase the fluidity of the composition. In addition, since a pozzolanic reaction occurs in place of the hydration reaction, a decrease in mechanical performance of the cured product can be suppressed. From the viewpoint that the hydration reaction proceeds sufficiently to obtain a cured product having excellent toughness, the total blending amount of one or more pozzolanic substances selected from silica fume, blast furnace slag, and fly ash is 5 to 40% by mass / water. Hard material, especially 5 to 20% by mass /
It is preferably a hydraulic material. Hydraulic material content C
(Kg / m ³ ) is 750 kg / m ³ or more, preferably 8 in view of obtaining a hydraulically cured product having sufficient mechanical performance.
There needs to be 00kg / m ³ or more, is required to be 1300 kg / m ³ or less from the viewpoint of securing the fluidity of the composition.

Further, in the present invention, the amount of aggregate S (kg / m ³ ) is 40
It is necessary to be 0 kg / m ³ or more, preferably 450 kg / m ³ or more, and it is necessary to be 1100 kg / m ³ or less from the viewpoint of securing the fluidity of the composition and suppressing the shrinkage of the cured product. .

As the water used in the present invention, for example, tap water, river water and the like may be used. From the viewpoint of securing the fluidity of the hydraulic material composition, the unit water amount W (kg / m ³ ) in the hydraulic material composition should be 270 kg / m ³ or more, preferably 300 kg / m ³ or more, and more preferably 320 k / m ³ or more.
g / m ³ or more. Further, from the viewpoint of retaining the mechanical properties of the cured product, the unit water amount W a ^{(kg / m 3) 420kg /} m 3 or less, preferably to a 400 Kg / m ³ or less.

The hydraulic material composition may be obtained by using a hydraulic material, a reinforcing fiber, an aggregate, and water so as to have the above-mentioned composition. In order to produce a cured product having excellent toughness, it is necessary to mix such materials so as to have a specific compounding ratio satisfying the following formulas (I) and (II). 2.625-0.0075 · X ≦ Y ≦ 3.375-0.0075 · X (I) 47 · Y + 253 ≦ W ≦ 47 · Y + 293 (II) In the formula, X is the fineness (dtex) of the reinforcing fiber, Y is a hydraulic material / aggregate mixture ratio (C / S), and W is a unit water amount (kg /
m ³ ). Conventionally, if the fineness of the fiber is increased, the uniform dispersibility is increased, but it is thought that the effect of suppressing the expansion of cracks is likely to be reduced due to the ease of "peeling out", but by adopting the above specific composition, Even when the fineness is relatively large, a cured product having excellent bending strength and toughness can be obtained. Specifically, since the fluidity of the composition, the mechanical performance, and the adhesiveness and stress conductivity of the fiber and the matrix greatly vary depending on the fineness of the reinforcing fiber, the mixing ratio of the hydraulic material and the aggregate is changed by the reinforcing fiber. It is necessary to determine, and further, it is necessary to determine the unit water amount based on the mixing ratio (see FIGS. 1 and 2). If the ratio is outside the above range, the fluidity of the composition will decrease, and the bending strength and toughness of the obtained cured product will decrease. In the case where a plurality of reinforcing fibers are used, the composition may be determined using the fineness of the fiber that is the main component of the reinforcing fiber as the fineness of the reinforcing fiber.

From the viewpoint of ensuring the fluidity and workability of the composition, the flow value is preferably 140 mm or more, particularly 150 mm or more, and more preferably 160 mm or more. Can be performed. From the viewpoint of obtaining a cured product excellent in mechanical performance and the like, the bending strength of a standard molded product obtained using such a composition is 10 MPa or more, particularly 12 MPa or more, and more preferably 1 MPa or more.
It is preferably 5 MPa or more, and from the viewpoint of obtaining a cured product excellent in toughness and earthquake resistance, the deflection of a standard molded product obtained using such a composition is 10 mm or more, particularly 11 mm or more, and more preferably 12 mm or more, especially It is preferably at least 14 mm.

Further, other additives and materials may be added. It is preferable to add a water reducing agent, particularly an AE water reducing agent, from the viewpoint of increasing the mechanical performance of the hydraulic molded body without impairing the fluidity of the paste. The applicable water reducing agent is not particularly limited, and examples thereof include high-performance AE water reducing agents such as polycarboxylic acid type, lignin sulfonic acid type, naphthalene sulfonic acid type, and melamine sulfonic acid type. By adding a high-performance AE water reducing agent, the amount of water in the composition can be reduced without substantially impairing the fluidity. In particular, when a polycarboxylic acid-based high-performance AE water reducing agent is used, the dispersibility of fibers, particularly PVA-based fibers, is remarkably improved, so that it can be used more preferably. Although the reason for improving the dispersibility of the PVA-based fiber is not particularly clear, the linear structure of the high-performance AE water-reducing agent combines the PVA-based fiber with the water-reducing agent and the fiber by hydrogen bonding to improve the dispersion state. It is presumed. Specific examples of the polycarboxylic acid-based high-performance AE water reducing agent include, for example, "Tupole" manufactured by Takemoto Yushi, "Darlex Super" manufactured by Denka Grace, "Reobuild" manufactured by NMB, "Parick" manufactured by Fujisawa Pharmaceutical, and "Matei" manufactured by Kao. And "Sunflow" manufactured by Sunflow. The addition amount of the water reducing agent may be appropriately set depending on other compounding materials and the like, but is usually 0.2 to 1 with respect to the hydraulic material.
Although it is necessary to add about 2% by mass, it is preferable to add about 2 times or more, specifically about 0.5 to 3% by mass. Specifically, it is preferable to mix 1 kg / m ³ or more, especially 3 kg / m ³ or more.
g / m ³ or less.

It is preferable to add a viscosity agent from the viewpoint of uniformly dispersing the components and suppressing the breathing. By adding such a viscosity agent, the viscosity of the composition is increased, and the shearing force between the fibers or between the fibers and the matrix is increased, so that the fibers are likely to be separated into single fibers, so that an excellent effect is obtained. . In particular, when the amount of water is increased in order to reduce the compressive strength of the molded body, the dispersibility of each material is increased, but the fibers are difficult to be formed into a single fiber. Dispersibility can be significantly improved. The viscous agent that can be used is not particularly limited, but a cellulosic compound, particularly a cellulosic compound having an alkoxy group (among others, one or more cellulosic compounds selected from methylcellulose, propylmethylcellulose, and hydroxyethylmethylcellulose) is preferably used. Is done. Among them, a cellulose compound in which a part of the hydroxyl group is substituted with one or more alkoxy groups selected from a methoxy group, an ethoxy group, a propoxy group, a hydroxypropoxy group, and a hydroxyethoxy group is preferably used. 1.
What substituted 5 to 2.5 hydroxyl groups with an alkoxy group can be used more suitably.

The amount of the viscous agent added depends on the fluidity of the paste,
What is necessary is just to determine suitably according to the dispersibility of a fiber, etc. In general, as the degree of polymerization of the viscosity agent increases, the viscosity of the paste increases with a small amount of addition.
000mPa · s or more, sometimes 100000m
Those having a pressure of about Pa · s are widely used. Although it is possible to use such a viscosity agent in the present invention,
In the present invention, more excellent effects can be obtained when a viscosity agent of 2000 to 8000 mPa · s, particularly 3000 to 5000 mPa · s is used. The amount of addition is 0.1 to 1% by mass, especially 0.3 to 1% by mass of water constituting the paste.
It is preferred to be about 0.5% by mass. In particular,
It is preferable to add about 0.1 to 10 kg / m ³ .

However, in order to obtain a hydraulically cured product having not only a high flexural strength but also a high toughness, it is necessary to use a hydraulic material composition in which the compression strength of the standard molded product is 120 MPa or less, particularly 100 MPa or less, and even 90 MPa or less. Is preferred. Although a molded article having a high compressive strength is unlikely to cause the first crack even when stress is applied, the stress at the time of the crack generation increases as the compressive strength increases. Since the reinforcing fiber used in the present invention has a relatively large diameter, the bridging effect is exhibited without breaking even when the compression strength of the molded body is high to some extent (even when the stress at the time of the first crack occurrence is high to some extent). However, if the compressive strength is too high, the fiber is broken before transmitting the stress to other fibers, so that the toughness tends to be reduced. Therefore, the compressive strength in the above range is preferable. However, when the compressive strength of the standard molded body is too low, the matrix itself is broken before the bridging effect is exerted by the reinforcing fibers, so that a molded body having high toughness cannot be obtained. Therefore, the compression strength of the standard molded body is preferably 30 MPa or more, particularly preferably 40 MPa or more. In addition, the compressive strength of the standard molded body referred to in the present invention refers to the compressive strength of a hydraulic molded body obtained by a method described in Examples using a sample composition. By using a composition in which the compressive strength of the standard molded product falls within the above range, a high-performance hydraulically cured product can be obtained. The compressive strength of the standard molded body can be adjusted by changing the type and amount of the hydraulic material, water, reinforcing fiber, aggregate, and other additives.

The method of adding the materials, the order of addition, and the kneading method are not particularly limited. Next, the obtained composition may be molded as required, and further cured to produce a cured product. The method for producing the cured product of the present invention is not particularly limited,
For example, a spray molding method, an injection molding method, a pressure molding method, a vibration molding method, a combined vibration and pressure molding method, a centrifugal force molding method, a winding molding method, a vacuum molding method, and an extrusion molding method can be used.
Of course, the present invention also includes an article (molded body) obtained by painting as a plastering material. In the present invention, a remarkable effect is obtained particularly when kneading and molding are performed. Incidentally, kneading molding according to the present invention, after uniformly kneading the matrix and fibers in a mud state in a system where water is present,
It refers to a method of molding into a desired shape by the molding method as described above, and is clearly distinguished from the papermaking method conventionally widely used. What is necessary is just to shape | mold by the said method and to cure | harden as needed. The curing method and the curing period are not particularly limited, and may be performed by a desired method such as room temperature curing, autoclave curing, steam curing, and underwater curing.

The molded article of the present invention can be any product, for example, pier reinforcement, pier beam, building column, formwork, underground wall, deep building material, marine / underwater structure, high altitude building Products, manholes, slate boards, pipes, wall panels, floor panels, shingles, partitions, road pavements, tunnel linings, slope protection, concrete factory products, etc. Can be used for secondary products. Further, the present invention is not limited to the above-mentioned cement products, and can be applied to structures other than these, interior and exterior members of buildings, and civil engineering materials. Further, it may be used as a plastering mortar, a machine base, a reactor pressure vessel, a container for liquefied natural gas, or the like. Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited to the examples.

[0021]

[Example] [Fineness dtex] The apparent fineness was measured at n = 5 or more by measuring the weight of a given test length of the obtained fibrous material.
The average was determined. In addition, the fineness could not be measured by measuring the weight of a certain yarn length (fine denier fiber) was measured by a vibroscope.

[Fiber strength cN / dtex] Temperature 20 in advance
The fibers were allowed to stand for 24 hours in an atmosphere of 65 ° C. and a relative humidity of 65% to adjust the humidity.
The fiber strength was measured in cm / min using an Instron tester “Autograph manufactured by Shimadzu Corporation”. The fiber length is 20
If it is shorter than cm, the maximum length of the sample within the possible range is measured as the grip length.

[Flow value mm] A cast iron cylinder having an upper side diameter of 7 cm, a lower side diameter of 10 cm, and a height of 6 cm was used.
cm of the cast iron disk, and the cylinder was gently stripped vertically after filling the cylinder with hydraulic paste and the paste was allowed to flow onto the disk. Then, after the disk is hit 15 times, the diameter of the paste spread by the hit or the like is measured in mm. If the spread does not become circular, the average value of the maximum diameter and the minimum diameter is used as the flow value.

[Standard molded body] The hydraulic composition is poured into a predetermined mold, and the surface is lightly lightened 4 to 5 times with a hand.
After wrapped in a polyethylene sheet at 65 RH and left for 24 hours, it was demolded and cured in water at 20 ± 1 ° C. for 27 days to produce a standard specimen. [Compressive strength MPa] A cylindrical body having a diameter of 5 cm and a height of 10 cm was formed into a sample (standard molded body), and 0.25 N / sec.
/ By applying a load at an increased speed of mm ² JIS A1108
-Measured according to 1993. [Bending strength MPa, deflection mm] A three-part bending test was performed using a standard molded body under the following conditions, and the bending stress when the maximum load occurred was defined as the bending strength, and the deflection when the bending strength was developed was read and evaluated. Apparatus Shimadzu Autograph AG5000-B Specimen Width 60mm, Thickness 10mm, Length 240mm Test speed 0.5mm / min.

Examples 1 to 6, Comparative Examples 1 to 7 Ordinary Portland cement (manufactured by Taiheiyo Cement) in an omni mixer, Toyoura standard sand as an aggregate, methylcellulose as a viscosifying agent ("High-Metroze 90SH" manufactured by Shin-Etsu Chemical Co., Ltd.)
4000 "), kneaded for 1 minute, and further mixed with water and a high-performance AE water reducing agent (" Reobuild SP-8 "manufactured by NMB Corporation).
N ") and kneaded for 30 seconds. Then, after scraping, kneading was further performed for 90 seconds, and then reinforcing fibers were added to the mixture.
After kneading for 0 second and then scraping off, the mixture was further kneaded for 90 seconds to prepare a hydraulic composition so as to have the composition shown in Table 1. A standard molded body was manufactured from the obtained composition, and the performance was evaluated. Table 1 shows the results.

The silica fume used was Union Chemical Co., Ltd., and fly ash was SiO ₂ = 53.4%, Al ₂ O ₃ = 26.0%, specific surface area 3000 cm ² / g, manufactured by Kanden Kagaku Corporation. Was used. In addition, the compounding amount of each material other than the fibers in Table 1 is the compounding kg per 1 m ³ .

[0027]

[Table 1]

Each of the compositions of the present invention had a high flow value and was excellent in fluidity and workability, and was easy to perform on-site. Moreover, the bending strength and toughness of the standard molded body obtained from such a composition were high.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the relationship between reinforcing fibers and hydraulic material / aggregate (C / S) in a hydraulic composition of the present invention.

FIG. 2 shows a hydraulic material / hydraulic material in the hydraulic composition of the present invention.
FIG. ³ is a schematic diagram showing a relationship between aggregate (C / S) and unit water amount (Kg / m ³ ).

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hisashi Suemori 1-2-1, Kaigandori, Okayama City Inside Kuraray Co., Ltd. (72) Inventor Hideki Hojo 1-12-13 Umeda, Kita-ku, Osaka Co., Ltd. F term in Kuraray (reference) 4G012 PA24 PC11 PC12 PE01

Claims (4)

[Claims] 1. A hydraulic material comprising at least one material selected from cement, silica fume, blast furnace slag, and fly ash, and comprising at least a cement-based hydraulic material, reinforcing fiber, aggregate and water. A material composition, wherein the fineness X (dtex) of the reinforcing fiber is 55 to 27.
0 dtex, and the hydraulic material content C (kg /
m ³ ) is 750 to 1300 kg / m ³ , and the amount of aggregate S (k
g / m ³ ) is 400 to 1100 kg / m ³ , and the amount of water is W
A hydraulic material composition having (kg / cm ³ ) of 270 to 420 kg / m ³ and satisfying the following formulas (I) and (II). 2.625-0.0075 · X ≦ Y ≦ 3.375-0.0075 · X (I) 47 · Y + 253 ≦ W ≦ 47 · Y + 293 (II) (where Y is C / S) 2. The hydraulic material composition according to claim 1, wherein at least a part of the reinforcing fibers is a polyvinyl alcohol-based fiber. 3. A fiber-reinforced hydraulic cured product obtained from the hydraulic material composition according to claim 1. 4. A method for on-site construction using the hydraulic material composition according to claim 1 or 2.