JP2000263541A - Manufacture of cement cured body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly mix a cement slurry composition in a short time by mixing at least reinforcing fibers, a filler and water under the wet conditions to improve the performance of a cement cured body because of the uniform mixture and stabilize the quality. SOLUTION: In a cement cured body manufacturing method in which a fast- setting cement slurry composition containing cement, water, reinforcing fibers, a filler and an admixture are kneaded continuously by a mixer, formed and cured, at least reinforcing fibers, a filler and water are mixed all together by a wet process preliminarily and a mixture formed therein is fed continuously into the mixer separately from the cement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hardened cement body, and more particularly, to a method for producing a hardened cement slurry composed of a plurality of raw materials and having a quick-setting property by homogeneously and continuously mixing within a short time. The present invention relates to a method for efficiently producing a hardened cement body.

[0002]

2. Description of the Related Art A hardened cement body, particularly a cement board, is produced by blending a reinforcing fiber, a filler material and an admixture in addition to cement and water. In the production method, from the viewpoint of efficiency, a method of forming and slurrying a cement slurry composition having rapid curing by continuous pouring is adopted (Japanese Patent Application Laid-Open No. H10-139520).

[0003]

This technique is epoch-making in that a cement-based plate material can be obtained efficiently within a short time, but since the cement slurry composition has a quick-setting property, The mixing of the raw materials must be completed within a short time, and as a result, continuous mixing with a very short residence time is required. On the other hand, in the production of these hardened cement bodies, it is difficult to uniformly mix them in a short time because a plurality of raw materials such as reinforcing fibers, filler materials, and admixtures are blended with the cement slurry composition. For this reason, a high-performance continuous mixer capable of strong stirring is used for mixing such raw material systems. However, these cement hardened bodies have a large specific gravity difference between raw materials and have different surface properties. Even with the use of a performance mixer, there is still a problem of lack of homogeneity.

Accordingly, an object of the present invention is to provide a method for efficiently mixing a cement slurry composition comprising a plurality of raw materials, which has a rapid setting property, in a short time to obtain a homogeneous hardened cement body efficiently. Is to provide.

[0005]

Means for Solving the Problems In view of this situation, the present inventors have conducted intensive studies, and as a result, at least water, reinforcing fibers and fillers among raw materials have been mixed in advance by a wet method, and components such as cement and the like have been obtained. As a result, if the cement slurry composition having quick setting is continuously and uniformly mixed in a short time if continuously supplied to the mixer separately, it has been found that a homogeneous hardened cement body can be produced industrially advantageously, The present invention has been completed.

That is, the present invention provides a method for producing a hardened cement body in which a rapidly hardening cement slurry composition containing cement, water, reinforcing fibers, filler and admixture is continuously kneaded with a mixer, molded and hardened. In, at least reinforcing fibers, filler and water are mixed in advance in a wet manner,
Another object of the present invention is to provide a method for producing a hardened cement, comprising continuously supplying the mixture to a mixer separately from the cement.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A cement slurry composition used for producing a hardened cement body of the present invention comprises cement, water,
It is a fast-curing material containing a reinforcing fiber, a filler and a mixture.

In order to achieve high productivity, the cement used in the present invention preferably has a fast setting property, that is, a cement which is less than 100 minutes in a Bigger needle test based on JIS R 5201. Specific examples include early-strength cement, jet cement, Irwin cement, and eco-cement. Here Ecocement is a hydraulic composition comprising one or more of the burned material selected from the county consisting municipal waste incineration ash and sewage sludge incineration ash, the C ₁₁ A ₇ CaCl ₂ 1
It is a hydraulic composition containing gypsum and a calcined product containing 0 to 40% by weight and containing at least one selected from the group consisting of C ₂ S and C ₃ S. Examples include a harmony type hydraulic composition, a rapid-hardening mixed cement disclosed in Japanese Patent Application Laid-Open No. H7-165447, and a cement using living and industrial wastes described in Japanese Patent Application Laid-Open No. 9-309750.

The cement which can be used in the present invention is not limited to the above-mentioned cement, provided that it is provided with a quick-setting property by using a hardening accelerator which is a kind of an admixture described later.
Cement with a slow setting speed such as ordinary Portland cement can also be used. Here, the hardening accelerator is compounded for the purpose of accelerating the hardening speed of the cement slurry. Examples of the hardening accelerator include calcium compounds (eg, slaked lime, quicklime, calcium chloride, calcium aluminate), and aluminum compounds (aluminum oxide, hydroxide). Aluminum), sulfates, and nitrates.

The reinforcing fibers used in the present invention are compounded for the purpose of improving mechanical strength and imparting workability.
Specifically, wood fillers such as wood chips and wood fibers, waste paper pulp, virgin pulp, organic fibers (eg, polypropylene (PP), vinylon, acrylic, etc.), inorganic fibers (wollastonite, rock wool, ceramic fibers, etc.), etc. Is mentioned.

The filler is reinforced, imparted with workability, reduced in weight,
It is blended for the purpose of increasing the weight, and examples thereof include inorganic and organic lightweight aggregates, crushed stones, fine and coarse aggregates, and the like. Specific examples include blast furnace slag, silica fume, silica flower silica, silica powder, and the like.

Specific examples of the admixture include a slurry fluidizer, a slurry viscosity modifier, a hardening accelerator, and various dispersants.

In the present invention, among these raw materials, at least reinforcing fibers, fillers and water are mixed in advance by a wet method. The mixing method may be batch or continuous, but batch mixing is preferred for homogeneous mixing. Here, as the mixer used for the pre-mixing, all commonly used mixers can be used, but specifically, a Henschel mixer, a paddle mixer, an omni mixer, a ribbon mixer, a ladyge (Proshare) mixer, and the like. Is mentioned.

In the present invention, the reinforcing fiber and the filler must be wet-mixed in advance, that is, mixed with water. Even if the reinforcing fiber and the filler are mixed in a dry state, they cannot be mixed uniformly. The effect of the invention cannot be obtained. Here, the compounding amount of water is from 20 to 20 as a water / cement ratio depending on the specific gravity of the obtained cement hardened body, desired strength and the like.
150% is preferred. And in this invention, it is preferable to use 90 to 100% of the compounding quantity of this water in this pre-mixing stage.

[0015] Among the admixtures, the slurry fluidizer, the slurry viscosity modifier and the various dispersants may be mixed in this premixing step or supplied together with the cement. More specifically, when these admixtures are in a liquid form, they need to be mixed in a premixing step, and when they are in a powder form, they can be supplied in a premixing step. , May be supplied with the cement. Further, among the admixtures, those which make the premix such as a hardening accelerator, particularly slaked lime alkaline, are preferably supplied together with the cement without being mixed in the premixing stage.

In the present invention, the cement is supplied to the mixer separately from the above-mentioned premixed components. As described above, examples of the cement include a rapidly hardening cement powder and a powdery raw material composed of cement and a hardening accelerator. The supply of the quick-setting cement powder or the powdery raw material comprising the cement and the setting accelerator to the mixer may be performed by a transfer path during which the premix is transferred to the continuous mixer, or directly to the continuous mixer separately from the premix. To supply. Here, in the case of employing the former supply method, since rapid-hardening cement is supplied in the slurry, it is necessary to supply the cement to a continuous mixer before a hardening reaction of the cement occurs. In particular, when rapid hardening is remarkable, sufficient consideration is required. Therefore, when using a cement having a remarkably fast setting property or a fast setting cement and a composition, it is preferable to supply the cement directly into the continuous mixer.

Subsequently, the slurry composition uniformly mixed by the continuous mixer is subjected to continuous casting to form a hardened cement. Continuous casting is a molding technique in which, for example, a slurry composition is poured into a molding die having a desired shape that is moving by a conveyor, and the slurry composition is cured while moving. This continuous casting is
Widely known in the industry. As the mixer, one capable of continuously feeding raw materials and continuously discharging the slurry composition mixed therein is preferable. The slurry composition is supplied to a mold that moves continuously or intermittently together with a conveyor, for example, and cures. A metal mold, resin, or the like can be used as the molding frame. However, when the slurry composition is heated in the molding frame, a material made of a heat-resistant material is desirable. Further, in order to improve the separation and demolding of the obtained cement hardened body and the molding form,
It is also preferable to adopt a mold material that is easy to release, or to take measures such as applying a release agent. Further, when various designs are desired to be applied to the hardened cement body, various processes can be applied to the molding form according to the designs. Subsequently, the cured cement body cured until it can be handled in the molding form is taken out of the molding form, but the cured cement body taken out at this time may be directly transferred to the curing process, or if necessary. A cutting process or a cutting process for the purpose of size adjustment, a cutting process for applying a surface design, or the like may be performed.

The compressive strength of the cement hardened material thus obtained is, for example, 20 kgf / cm ² -4 hours after water injection.
0kgf / cm ^{2, 2} hours at 40kgf / cm ² ~60kgf / cm ²
Which is practically sufficient. Further, the form of the cement hardened material is preferably a cement-based plate material such as ALC and sizing.

[0019]

Next, the present invention will be described in detail with reference to examples and comparative examples of the present invention, but the present invention is not limited to these examples.

In the production of a cement hardened material described below, a trial production was performed using a gypsum board production line, which is a typical continuous casting process. First, the slurry composition, a raw material and water that has been wet-mixed in advance with a predetermined type of cement are continuously supplied to a continuous mixer, and bubbles formed by foaming a predetermined surfactant by a preform method are added. After kneading, the mixture was continuously discharged from the mixer. The slurry composition was continuously poured into a resin mold placed on a molding line as a conveyor and molded. After curing for 1 to 3 hours in the mold on the conveyor, the resin composition was further cured. After demolding from the mold making frame, a prototype was produced by curing in an autoclave at 140 ° C. for 3 hours or 180 ° C. for 6 hours.

The obtained cured cement was evaluated by the following method. (1) Surface Properties The surface condition of the prototype cement hardened material was visually observed.

(2) Flexural strength test No. 3 specimen (40 cm × 5)
0cm x 1.5cm) specimen was prepared and loaded by 3-point bending using an Instron universal testing machine, and the distance between fulcrums was 40c.
m at a loading speed of 1 mm / min.

(3) Fluidity The slurry composition obtained by the above method was sufficiently spread in a mold on a molding line and formed without any problem (◎). The product that was formed by performing the above operation was evaluated as (）), the product that could be formed by external energy such as vibration + trowel work by a human being (△), and the product that could not be formed without spreading at all was evaluated as (x).

The raw materials used in these examples and comparative examples are as follows. Table 2 shows a raw material composition table used in Examples and Comparative Examples of the present invention.

Cement: Ecocements A and B (manufactured by Taiheiyo Cement Co., Ltd.) See Table 1 for mineral composition. Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation)

[0026]

[Table 1]

Water: tap water Water reducing material: naphthalene sulfonic acid-based water reducing agent (manufactured by Sanyo Kokusaku Pulp Co., Ltd.) Slaked lime: industrial slaked lime (Kotegawa Sangyo Co., Ltd.) Aluminum sulfate (Kanto Chemical Co., Ltd.) Reagent・ Quick lime: Industrial quick lime (Yoshizawa Lime Co., Ltd.) ・ Silica: Industrial silica ・ Fly ash ・ Methylcellulose: High Metrose (Shin-Etsu Chemical Co., Ltd.)
・ Glass fiber: alkali-resistant glass fiber 12 mm chopped strand ・ Foaming agent: D3D Emar (Kao Corporation)

[0028]

[Table 2]

Table 3 shows cured cements of Examples 1 to 6 and Comparative Examples 1 to 4.

Examples 1 to 6 and Comparative Examples 1 to 4 In Examples 1 to 6, the non-hydraulic raw materials excluding cement were preliminarily mixed by a wet method, and the mixture was continuously supplied to a continuous mixer. It is a cement hardened body obtained by mixing. Examples 1 and 4 are quick-setting cements, Examples 2 and 5 are those in which a hardening accelerator is used in combination with a quick-setting cement, and Examples 3 and 6 are a combination of a cement that does not show quick-setting and a hardening accelerator. Using this, a cement hardened body according to the present invention was prototyped. As comparative examples, those obtained by dry-mixing the non-hydraulic raw materials in advance are described in Comparative Examples 1 and 3, and those obtained by directly charging the non-hydraulic raw materials into the mixer without preliminary mixing are also described in Comparative Examples 2 and 4.

In Examples 1 to 6, first, a predetermined amount (see Table 2) of a non-hydraulic raw material was mixed with water (50 W based on the amount of powder) using a 150 L Henschel mixer (manufactured by Mitsui Mining Co., Ltd.).
t. %). The wet mixture was continuously supplied to a continuous mixer, and mixed with cement and a hardening accelerator or a quick-setting cement to obtain a slurry composition. The slurry composition is continuously cast into a resin mold placed on a molding line that is a conveyor as described above, and is placed in the mold on the conveyor for 1 to 3 hours. After curing as it was, the mold was released from the resin mold, and cured in an autoclave at 140 ° C. for 3 hours or 180 ° C. for 6 hours to produce a prototype. The cured products of Comparative Examples 1 and 3 were produced by mixing non-hydraulic raw materials in advance in a dry manner, and charging the mixture into a continuous mixer. Further, the cured products of Comparative Examples 2 and 4 were obtained without premixing the non-hydraulic raw material.
It is manufactured by directly charging it into a continuous mixer. In Comparative Examples 1 and 2, the same blending conditions as in Example 1 were used, and Comparative Examples 3 and 4 were used.
Was performed under the same blending conditions as in Example 6.

[0032]

[Table 3]

As shown in Table 3, the hardened cements of Examples 1 to 6 obtained by premixing non-hydraulic raw materials other than cement in a wet manner were obtained in Comparative Examples 1 and 3 in which the non-hydraulic raw materials were premixed in a dry manner.
The mechanical strength such as bending strength and specific strength is improved as compared with the cured products of Comparative Examples 2 and 4 in which the cured product and non-hydraulic raw materials of Comparative Examples 2 and 4 were directly charged into a mixer without premixing and molded. It could be confirmed. Also, the state of the surface of the cured product can be visually determined that the cured products of Examples 1 to 6 have a uniform color while the cured products of Comparative Examples 1 to 4 have a mottled pattern. It was confirmed that when the hard raw materials were mixed in a wet manner, the quick-hardening cement composition could be homogeneously mixed in a short time.

Next, Examples 7 to 11 and Comparative Examples 5 and 6 are shown in Table 4. Examples 7 to 11 and Comparative Examples 5 and 6 Non-hydraulic raw materials other than cement were premixed in a wet manner using a Henschel mixer in the same manner as in Examples 1 and 6 in Examples 7 and 10, and this premix was supplied to the mixer. 1 shows a hardened cement body produced by supplying a quick-setting cement or a cement and a hardening accelerator into a transfer route, and simultaneously adding and mixing the cement into a continuous mixer. Examples 8, 9, 11
And the hardened cement produced by directly charging the cement and the hardening accelerator to the continuous mixer. Further, when pre-mixing the non-hydraulic raw materials in Comparative Examples 5 and 6, after adding and mixing a quick-setting cement or cement and a hardening accelerator, this pre-mixture was continuously charged into a continuous mixer to produce a hardened cement. Show body.

[0035]

[Table 4]

From Table 4, it was confirmed that the cured cements of Examples 7 to 11 had improved mechanical strength such as bending strength and specific strength as in Examples 1 to 6 shown in Table 1. In addition, the state of the surface of the cured product was visually determined to be uniform, similarly to the cured products of Examples 1 to 6, and it was confirmed that the quick-setting cement slurry could be uniformly mixed in a short time. In Comparative Examples 5 and 6, due to the hardening of the cement due to the hydration reaction of the cement in the transfer route, stiffness was generated in the slurry, and the slurry blocked the transfer route and could not be supplied to the continuous mixer, or the mold on the conveyor was not used. Molding was impossible because the slurry did not spread sufficiently in the frame.

[0037]

The cement slurry composition can be homogeneously mixed in a short time by preliminarily mixing the reinforcing fibers, fillers and water under wet conditions. Performance is improved and quality is stabilized.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C04B 16:06 16:02) 111: 00 (72) Inventor Norifumi Nagata 2-4 Daisaku, Sakura City, Chiba Prefecture No. 2 F-term in Building Materials Techno Research Laboratories (reference) 4G012 PA15 PA24 PA27 PA29 PB41 PE01 4G056 AA08 AA13 AA18 AA19 CC39

Claims (2)

[Claims] 1. A method for producing a hardened cement material, comprising a step of continuously kneading a cement slurry composition containing cement, water, reinforcing fibers, fillers and an admixture, kneading with a mixer, molding and hardening at least. A method for producing a hardened cement, comprising mixing fibers, fillers and water in advance by a wet method, and continuously supplying the mixture to a mixer separately from cement. 2. The method for producing a hardened cement according to claim 1, wherein a rapidly hardening cement powder or a powdery raw material comprising cement and a hardening accelerator is supplied to a mixer separately from said mixture.