JPH05345648A - Cement composition and method for casting cement hardened product - Google Patents

Abstract

PURPOSE:To obtain the cement composition comprising a cement, silica fume, a water-reducing agent, water and synthetic fibers in a specific ratio, improved in the dispersibility of the synthetic fibers, and useful for cast products having high strengths. CONSTITUTION:100 Pts.wt. of a cement is mixed with 3-30 pts.wt. of silica fume, 0.1-5 pts.wt. of a water-reducing agent (e.g. an alkylarylsulfonic acid salt) and 25-45 pts.wt. of water and subsequently with 0.3-3 pts.wt. of synthetic fibers (e.g. vinylic fibers) each having a thickness of 2-40 denier and a length of 3-15mm with vibration to provide the composition. An openable mold 1 comprises an outer mold 11 and an inner mold 12, has a cavity 13 corresponding to the outer shape of a cured product between the outer and inner molds 11, 12, and has an opening 131 at the upper part of the cavity. The casting of the composition is performed by vibrating the mold 1 with a vibrator 2 and simultaneously pouring the composition from the opening 131 to cast the composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cement-based compounding composition for casting a cement-based cured product, which improves the dispersibility of synthetic fibers and forms a high-strength cement-based cured product, and a cement-based cured product. The present invention relates to a method for casting a product.

[0002]

2. Description of the Related Art Asbestos is used as a reinforcing material in a cement-based cured product in order to improve the moldability during molding and to improve the mechanical strength after molding. Recently, asbestos is used. Some health problems have been pointed out. For this reason, various synthetic fibers are used as a reinforcing material in place of asbestos.

As a method for obtaining a cement-based cured product reinforced with such a synthetic fiber, for example, JP-A-58-213 is used.
As described in Japanese Patent No. 666, cement is mixed with an inorganic filler and synthetic fiber, and the amount is 15 per 100 parts of cement.
A method has been proposed in which -30 parts of water is added, and the mixture is kneaded using a kneader, a pressure kneader, a barber, or the like, and then the required water is added to the surface of the molded body and then shaped.

[0004]

However, in the conventional method as described above, the synthetic fibers are liable to be entangled with each other to form a fiber ball, and the fiber ball once formed is not easily opened, and the cement There is a problem that it is not possible to obtain a mixture in which the fibers are uniformly dispersed in the matrix, and the mechanical strength of the molded cured product is insufficient.

The present invention solves the above-mentioned conventional problems, improves the dispersibility of synthetic fibers, and obtains a high-strength cement-based cured product, which is a cement for cast-molding a cured cement-based product. The present invention has been made for the purpose of providing a system-containing composition and a method for casting a cement-based cured product.

[0006]

According to the invention of claim 1 of the present application, silica fumes 3 to 30 are added to 100 parts by weight of cement.
Cement-based compounding composition for cast molding of a cement-based cured product, in which 0.1 part by weight of water-reducing agent, 0.1-5 parts by weight of water, 25-45 parts by weight of water, and 0.3-3 parts by weight of synthetic fiber are added. It is a thing.

According to the invention of claim 2 of the present application, the cement 100
In the first step of adding 3 to 30 parts by weight of silica fume to the parts by weight and mixing, and the mixture obtained in the first step,
A second step of adding 0.1 to 5 parts by weight of a water reducing agent and 25 to 45 parts by weight of water and mixing, and 0.3 to 3 parts by weight of synthetic fibers in the mixture obtained in the second step. Pour the hardened cementitious material having a third step of adding oscillating mixture and performing rocking mixing, and a fourth step of casting and curing the mixture obtained in the third step into an openable mold. It is a molding method.

The invention according to claim 3 of the present application is the cement 100
Obtained in the first step of adding 3 to 30 parts by weight of silica fume, 0.1 to 5 parts by weight of a water reducing agent, and 25 to 45 parts by weight of water, and mixing them in parts by weight. A second step of adding 0.3 to 3 parts by weight of synthetic fiber to the mixed mixture and performing oscillating mixing, and the mixture obtained in the second step is poured into an openable mold to be shaped and cured. It is a method of casting a cement-based cured product, which comprises a third step.

In the present invention, cement refers to hydraulic cement such as Portland cement, alumina cement, blast furnace cement and the like.

In the present invention, as synthetic fibers, for example, fibers of vinylon, polyamide, polypropylene, etc. are used, and those having a thickness of 2 to 40 denier and a length of 3 to 15 mm are preferably used.

The amount of synthetic fiber added is 0.3 to 3 parts by weight per 100 parts by weight of cement. Addition amount is 0.3
If the amount is less than parts by weight, the desired strength of the cured product cannot be obtained. On the contrary, if the amount is more than 3 parts by weight, the dispersion of synthetic fibers is poor, and the flowability during casting is poor. ..

In the present invention, silica fume refers to amorphous silica fine particles having a spherical shape, porosity, a high specific surface area, and a high silicic acid content as a chemical component.

Since silica fume has a spherical shape, is porous and has a high specific surface area, the cement-based compounding composition paste to which it is added has an appropriate viscosity and slipperiness with respect to synthetic fibers. When the synthetic fibers are mixed therein, silica fume easily enters between the fibers of the synthetic fibers, and the synthetic fibers can be uniformly dispersed.

Further, since silica fume has a high content of silicic acid as a chemical component, it is known that it reacts with cement to form fine particles insoluble in water. Is a reaction between calcium hydroxide and amorphous silica fine particles produced by a reaction between cement minerals and water, and as a result of the reaction, calcium hydroxide disappears and a new calcium silicate hydrate is produced. This is generally called the porazon reaction, and as a result of the porazon reaction, the cement-based cured product has both increased durability and strength.

The amount of silica fume added is 10
It is 3 to 30 parts by weight with respect to 0 parts by weight. Addition amount is 3
If it is less than 30 parts by weight, the desired curing cannot be expected. On the contrary, if it exceeds 30 parts by weight,
The viscosity of the cement-based compounding composition paste increases, making it difficult to use it for casting, and the excess amount is no longer involved in the porazon reaction, and is involved in increasing the durability and strength of the hardened cement product. do not do.

In the present invention, as the water reducing agent, conventionally known ones can be used, those containing lignin sulfonate or its derivative as a main component, those containing oxyorganic acid as a main component, and alkylallyl sulfonic acid. Salt-based, polyol complex-based, aromatic polycyclic condensation product sulfonate-based, water-soluble melamine formalin resin sulfonate-based, etc. Is mentioned.

The water-reducing agent can be used for cast molding because the cement-based compounding composition paste to which the water-reducing agent is added has at least an appropriate flowability of water. And, the cement-based cured product obtained does not have the layer separation that occurs when a large amount of water is added, and the durability and strength of the obtained cement-based cured product are increased.

The water reducing agent is added in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of cement. If the addition amount is less than 0.1 parts by weight, the desired effects as described above cannot be expected, and conversely, if the addition amount exceeds 5 parts by weight, the curing of the cementitious compounding composition paste is delayed. To do.

In the present invention, the amount of water added is 25 to 45 parts by weight with respect to 100 parts by weight of cement. When the addition amount is less than 25 parts by weight, the amount of the reaction with cement is insufficient, and the durability and strength of the cement-based cured product are not sufficient. Conversely, when it exceeds 45 parts by weight, the layers are separated. Cause deterioration in durability and strength.

In the cementitious composition of the present invention, in addition to the above additives, silica sand, river sand, fly ash, bentonite, sepiolite, wollastonite, calcium carbonate, mica, blast furnace slag, etc. are added, if necessary. can do.

In the present invention, the oscillating mixing is a device in which a flexible rubber container is mounted on a disk-shaped oscillating plate without using stirring blades, and the oscillating plate is inclined with respect to its inclination direction. By changing continuously, the rubber container containing the materials to be mixed rocks while deforming, accelerating the contents, changing the speed and direction, scattering in random directions and mixing. It means to do. 1 cycle of rocker movement is 1-3
Times / second.

In the casting method of the hardened cementitious material according to the second aspect of the present invention, 3 to 30 parts by weight of silica fume is added to 100 parts by weight of cement and mixed in the first step. As a result, the fine particles of the cement are mixed so as to be uniformly dispersed among the fine particles of the silica hue. As a mixing method, a mixer having a conventionally known rotary blade may be used for mixing.
Alternatively, oscillating mixing may be performed.

Next, in the second step, 0.1 to 5 parts by weight of a water reducing agent and 25 to 25 parts of water are added to the mixture obtained in the first step.
45 parts by weight are added and mixed. As a result, a cement paste in which cement, silica fume, a water reducing agent, and water are mixed so as to be uniformly dispersed is obtained. The mixing method is the same as in the second step.

Next, in the third step, 0.3 to 3 synthetic fibers are added to the cement paste obtained in the second step.
Add parts by weight and perform rocking mixing. The cement-based paste has appropriate viscosity and slipperiness with respect to the synthetic fiber, and by this mixing, the cement-based paste easily enters between the fibers of the synthetic fiber, and the synthetic fiber can be uniformly dispersed. By this oscillating mixing, a cement-based compounding composition paste in which synthetic fibers are uniformly dispersed and mixed in the cement-based paste can be obtained.

Further, in the fourth step, the cement-based compounding composition paste obtained in the third step is poured into a mold that can be opened and closed to be shaped and cured. In addition, when pouring into the mold, it is preferable to place the mold on an appropriate vibration device and vibrate the vibration device at a frequency of 1000 to 4000 VPM. Thereafter, the cement-based cured product that has been demolded and molded is taken out, and the molding is completed.

In the casting method of the hardened cementitious material of the invention of claim 3 of the present application, the first step and the second step of the molding method of the invention of claim 2 of the present application are simultaneously mixed. .. In this case, although the dispersibility of the cement between the fine particles of silica fume is slightly lowered, a cement-based paste in which the cement, silica fume, the water reducing agent and water are uniformly dispersed can be obtained. Since the other points are the same as the molding method of the invention of claim 2 of the present application, detailed description thereof will be omitted.

[0027]

The cement-based composition according to claim 1 of the present application comprises 100 parts by weight of cement, 3 to 30 parts by weight of silica fume, 25 to 45 parts by weight of water, and 0.1 to 5 parts by weight of a water reducing agent. Since 0.3 to 3 parts by weight of synthetic fibers are added, the paste in which these are mixed has the synthetic fibers uniformly dispersed and has excellent fluidity, so that the cement-based hardening with excellent strength is achieved. It can be suitably used as a raw material for casting of materials.

In the casting method of the hardened cementitious material according to claim 2 of the present application, in the first step, 3 to 30 parts by weight of silica fume is added to 100 parts by weight of cement and mixed to form fine particles of silica fumes. In the meantime, it is possible to mix so that finer-grained cement than that is uniformly dispersed. In the second step, 0.1 to 5 parts by weight of a water reducing agent and 25 to 45 parts by weight of water are added to and mixed with this mixture to uniformly disperse the cement, silica fume, water reducing agent and water. Can be mixed as.

In the third step, 0.3 to 3 parts by weight of synthetic fibers are added to the obtained cement-based paste, and the mixture is subjected to oscillating mixing so that the synthetic fibers are appropriately mixed with each other. It is possible to obtain a cement compounding composition paste in which synthetic fibers are uniformly dispersed by allowing a cement paste having a high viscosity and slipperiness to enter. This cement compounding composition paste has synthetic fibers uniformly dispersed therein, has little water content, is difficult to be separated, and has excellent fluidity.

Further, by using this cement composition paste as a raw material, in the fourth step, the mixture obtained in the third step is cast into a mold that can be opened and closed to be shaped and cured to give synthetic fibers. It is possible to form a cement-based cured product that is uniformly dispersed and has excellent strength.

According to a third aspect of the present invention, in the first step, in the first step, 100 parts by weight of cement, 3 to 30 parts by weight of silica fume, and 25 to 4 parts of water are contained in 100 parts by weight of cement.
By adding 5 parts by weight and 0.1 to 5 parts by weight of the water reducing agent and mixing, the cement, silica fume, water reducing agent and water can be mixed so as to be uniformly dispersed.

In the second step, 0.3 to 3 parts by weight of synthetic fibers are added to the obtained cement-based paste, and the mixture is subjected to oscillating mixing so that the synthetic fibers are appropriately mixed between the fibers. It is possible to obtain a cement compounding composition paste in which synthetic fibers are uniformly dispersed by allowing a cement paste having a high viscosity and slipperiness to enter. This cement compounding composition paste has synthetic fibers uniformly dispersed therein, has little water content, is difficult to be separated, and has excellent fluidity.

Further, by using this cement composition paste as a raw material, in the third step, the mixture obtained in the second step is cast into a mold that can be opened and closed to be shaped and cured to give synthetic fibers. It is possible to form a cement-based cured product that is uniformly dispersed and has excellent strength.

[0034]

EXAMPLES Examples of the present invention will be described below. Example 1 5 parts by weight of silica fume was added to 100 parts by weight of ordinary Portland cement and mixed by a mixer (first step). To this mixture, 36 parts by weight of water and 0.5 parts by weight of a water-reducing agent containing alkylallyl sulfonate as a main component (manufactured by Kao: trade name "Mighty 150") were added and mixed in a mixer. Thus, a cement paste was obtained (second step).

To this cement paste, 1 part by weight of vinylon fiber (fiber length 4 mm, thickness 5 denier) was added as a synthetic fiber, and the mixture was rocked and mixed by a mixer to obtain a cement mixture paste. (Third step). As the above mixer, an omni mixer (capacity 5 l) manufactured by Chiyoda Technology Co., Ltd.
It was used.

This cement-based mixture paste is shown in FIG.
Cast molding was performed in the process as shown in FIG. 3 (fourth process).

First, as shown in FIG. 1, an outer mold 11 and an inner mold 1
2 and a cavity 13 corresponding to the outer surface shape of the cured product to be molded is provided between the outer mold 11 and the inner mold, and the cavity 13 is inside the cavity 13 of the mold 1 in which an opening 131 is provided above. While vibrating by the vibration device 2,
The raw material mixture was poured from the opening 131. Next, it was naturally cured for 1 day in the state shown in FIG. Then, as shown in FIG. 3, the cement 1 hardened body was obtained by removing the mold 1.

Regarding the obtained cement-based cured product, JI
When the specific gravity was measured according to S R 5201,
It was 1.71. Further, the bending strength was measured according to JIS A 1408 and found to be 165 kg / cm ² .

Example 2 A cement-based cured product was obtained in the same manner as in Example 1 except that the first step and the second step were mixed at the same time. When the specific gravity of the obtained cement-based cured product was measured in the same manner as in Example 1, it was 1.72. Also, the bending strength was measured in the same manner as in the Example, and it was 141 kg / cm ² .

Comparative Example A cement-based cured product was obtained in the same manner as in Example 2 except that synthetic fibers were also mixed at the same time. When the specific gravity of the obtained cement-based cured product was measured in the same manner as in Example 1, it was 1.70. Further, the bending strength was measured in the same manner as in the example and found to be 105 kg / cm ² .

[0041]

Since the invention of claim 1 of the present application has the above-mentioned constitution, the paste in which these are mixed has the synthetic fibers uniformly dispersed therein and has excellent fluidity, so that the strength is improved. It can be suitably used as a raw material for cast molding of an excellent cement-based cured product.

Since the inventions of claim 2 and claim 3 of the present application are configured as described above, the synthetic fibers are uniformly dispersed, the water content is small, the separation is difficult, and the fluidity is excellent. It is possible to obtain a cement composition paste in the state of being prepared, and by using this as a raw material, a cement-based cured product in which synthetic fibers are uniformly dispersed and which is excellent in strength can be formed by casting.

[0043]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a raw material is poured into a mold in an embodiment of a method for casting a cement-based cured product of the present invention.

FIG. 2 is a schematic diagram showing a method of casting a cement-based cured product according to an embodiment of the present invention.
It is sectional drawing which shows the state to cure.

FIG. 3 is a cross-sectional view showing a state where the cement-based cured product is taken out from the cement-based cured product according to the embodiment of the casting method of the cured cement-based product of the present invention.

[Explanation of symbols]

 1 type 2 vibration device 11 outer type 12 inner type 13 cavity 131 opening

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Claims (3)

[Claims] 1. 100 parts by weight of cement, 3 to 30 parts by weight of silica fume, 0.1 to 5 parts by weight of a water reducing agent, and 2 parts of water.
5 to 45 parts by weight and 0.3 to 3 parts by weight of synthetic fibers are added, and a cementitious compounding composition for cast molding of a hardened cementitious material. 2. A first step of adding 3 to 30 parts by weight of silica fume to 100 parts by weight of cement and mixing, and 0.1 to 5 parts by weight of a water reducing agent to the mixture obtained in the first step. A second step of adding 25 to 45 parts by weight of water and mixing, and to the mixture obtained in the second step, synthetic fiber 0.3
A third step of adding 3 parts by weight to perform rocking mixing, and a fourth step of casting and curing the mixture obtained in the third step into a mold that can be opened and closed. A method for casting a cured cement-based material. 3. 100 parts by weight of cement, 3 to 30 parts by weight of silica fume, 0.1 to 5 parts by weight of a water reducing agent, and 2 parts of water.
The first step of adding 5 to 45 parts by weight and mixing, and the second step of adding 0.3 to 3 parts by weight of synthetic fiber to the mixture obtained in the first step and performing oscillating mixing A method for casting a cement-based cured product, comprising: a step; and a third step of casting and curing the mixture obtained in the second step into a mold that can be opened and closed.