JP2673218B2 - Manufacturing method of fiber-reinforced slag gypsum cement-based lightweight cured product - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a fiber-reinforced slag gypsum cement-based lightweight cured product, and more specifically, water resistance and durability used for an outer wall material and an inner wall material of a building. The present invention relates to a method for producing a lightweight building material having excellent fire resistance and fire resistance.

<< Prior Art >> As a conventional lightweight building material, there is a gypsum-based building material represented by a gypsum board that uses the setting and hardening of hemihydrate gypsum or anhydrous gypsum. In addition, plaster / slag type or plaster / slag /
Cement-based composite building materials have been commercialized. Further, a fast-setting cement composition composed of Portland cement, alumina cement, gypsum and lime has been proposed, and in recent years, a wood cement board has been produced using this composition. In addition, there are lightweight building materials that are autoclaved, such as ALC.

<Problems to be solved by the invention> Conventional gypsum-based building materials have the advantage that they can be molded and processed in a short time because they use the setting and hardening characteristics of hemihydrate gypsum, but on the other hand, gypsum is the main Since it is made of wood, there is a problem in that it has poor water resistance. In addition, gypsum / slag-based or gypsum-slag-cement-based composite building materials with improved water resistance have been commercialized, but in order to be able to mold and process them in a short time, a considerable amount is required. We had no choice but to use Hemihydrate gypsum, which left a problem in terms of water resistance. On the other hand, if the amount of hemihydrate gypsum is reduced, the problem of water resistance can be solved, but there is a problem that molding and processing cannot be performed in a short time.

Also, by using a cement composition with a fast hardening property consisting of Portland cement, alumina cement, gypsum and lime, it is possible to mass-produce building materials with a large degree of freedom in terms of shape and thickness, etc. The building material produced as a material has problems such as a building material having poor dimensional stability and poor long-term durability even with a slight change in the amount of the four components. In addition, in order to continuously mass-produce conventional cement-based building materials, curing by a papermaking method or autoclave is required, and it is difficult for the former to produce building materials with a thickness of 20 mm or more. However, in the latter case, there are problems such as poor workability on site such as cutting and nailing, and enormous equipment cost.

Therefore, the inventors of the present invention, in Japanese Patent Application No. 1-139647,
A method for producing a fiber-reinforced slag gypsum cement-based light-weight cured product is proposed. However, in the subsequent research, the building material manufactured according to the present invention was still insufficient in dimensional stability during long-term outdoor exposure, kneading of slurry, and coarse air bubbles (diameter 1 mm or more) involved in molding. It turned out to be.

The present inventors focused on rapid setting and hardening development of a composition consisting of Portland cement, calcium aluminate, gypsum, lime and slag fine powder at room temperature, and improved the dimensional stability and durability of the cured product of this system. In order to achieve this, extensive experiments were conducted in a system in which the aggregate of this system was added, and a coagulation regulator, air bubbles and reinforcing fibers were introduced. In addition, for the purpose of removing coarse bubbles entrained at the time of kneading and molding of the slurry, the inventors have earnestly studied the method of applying vibration to the slurry and blowing compressed air to the slurry, and the fiber-reinforced slag gypsum cement-based lightweight cured product of the present invention. Has completed the manufacturing method.

<< Means for Solving the Problems >> The present invention is based on 100 parts by weight of Portland cement, 20 to 350 parts by weight of slag fine powder, 0 to 20 parts by weight of lime, and the total amount of calcium aluminate and gypsum fine powder. Is 20
To 100 parts by weight, and 5 to 140 parts by weight of an aggregate having a maximum particle size of 2,000 μm or less is added to the mixture having a weight ratio of gypsum fine powder and calcium aluminate of 0.5 to 2.0, Further, 0.01 to 1.5 parts by weight of a coagulation regulator is added to the mixture, a slurry in which water, bubbles and reinforcing fibers are mixed is molded, demolded, and steam-cured.

The slag fine powder is a slag fine powder obtained by crushing granulated blast furnace slag and then classifying it, and has a fineness of 6,000 to 12,000 cm ² / g in terms of Blaine specific surface area.

The above calcium aluminate is CA, CA ₂ , C ₃ A, C
_{One of 12} A ₇ · CaF ₂ or a mixture of two or more kinds, and the total content of these is 50% or more.

The fineness of the gypsum fine powder has a Blaine specific surface area.
It is characterized by 2,500 cm ² / g or more and 88μ sieve residue of 0.5% or less.

When molding the slurry, the slurry has a frequency of 100 to 1
It is characterized by applying a vibration of 0,000 VPM.

When the slurry is molded, compressed air is blown onto the slurry.

The above-mentioned slurry is characterized in that it can be set and hardened within 3 to 60 minutes after molding and can be immediately demolded and processed.

The steam curing temperature is 90 ° C or higher, and the curing is performed at 150 ° C / hour or higher.

The cured product has an air-dry specific gravity of 0.4 to 1.5.

<< Working >> The quick-setting cement composition used in the present invention comprises 20 to 350 parts by weight of slag fine powder, 0 to 20 parts by weight of lime, and calcium aluminate and gypsum fine powder to 100 parts by weight of Portland cement. The total amount consists of 20 to 100 parts by weight, and the weight ratio of gypsum fine powder and calcium aluminate is 0.
For the mixture, which is 5 to 2.0, 0.01 to 1.
It is a hydraulic material characterized by adding 5 parts by weight.

As the coagulation regulator, oxycarboxylic acids such as citric acid, malic acid, glycolic acid, and 2 ketoglycolic acid, or
Its salts can be used, among them gluconic acid, or
The salt is preferred. The setting regulator may be added and mixed at the time of kneading the slurry, or premixed with the cement composition before use. If necessary, a water reducing agent such as a lignin-based, melamine-based, or naphthalene-based water reducing agent can be used.

Of the fast-setting cement composition according to the present invention, the total amount of calcium aluminate and gypsum fine powder to 100 parts by weight of Portland cement is 20 to 100 parts by weight, preferably 40 to 80 parts by weight, gypsum fine powder. And the weight ratio of calcium aluminate should be in the range of 0.5-2.0. The total amount of calcium aluminate and gypsum fine powder is 10
If the amount exceeds 0 parts by weight, the amount of ettringite produced becomes excessively large, and there is a risk of expansion and destruction, and the manufacturing cost increases. Further, when the total amount of calcium aluminate and gypsum fine powder is 20 parts by weight or less, rapid hardening becomes weak. Next, the reason why the weight ratio of gypsum fine powder and calcium aluminate is limited to the range of 0.5 to 2.0 is that the strength is poorly expressed when the weight ratio is 0.5 or less, and the amount of ettringite produced when the weight ratio is 2.0 or less. It becomes too large and there is a risk of expansion and destruction. When the weight ratio of the gypsum fine powder and calcium aluminate is in the range of 0.5 to 2.0, rapid hardening is exhibited with no shrinkage or expansion that does not adversely affect strength.

The calcium aluminate used in the present invention, including alumina cement, if it is a calcium aluminate-based mineral that is currently on the market, it will be amorphous,
Either crystalline or crystalline can be used. When a commercially available material consisting of calcium aluminate and anhydrite is used, it can be used after being corrected so as to fall within the scope of the claims of the present invention.

Next, the gypsum to be used may be anhydrous gypsum, hemihydrate gypsum, dihydrate gypsum, or a mixture of two or more kinds, and may be a natural product or a by-product. If the gypsum has a coarse powder, the rapid hardening property and the strength development are deteriorated, and the gypsum remains as unreacted gypsum and becomes a causative substance such as dimensional stability or expansion cracks. For this reason, the fineness of the gypsum fine powder is 2,500 cm ² / g or more in the Blaine specific surface area,
Preferably, 6,000 cm ² / g or more is suitable, and 88μ
Those with 0.5% or less remaining in the sieve are suitable.

For the purpose of shortening the setting time of the slurry prepared from the three-component composition in which Portland cement, calcium aluminate and fine gypsum powder are combined,
It is also possible to use lime together in the component system. The use of lime is effective especially in winter when the outside temperature is low. In the summer when the outside air temperature is high, it is not always necessary to use lime together, but it is preferable to control the setting time and setting strength by the addition amount of a setting regulator such as citric acid in order to prolong the setting time.

Therefore, the amount of lime used is 0 to 20 parts by weight with respect to 100 parts by weight of Portland cement. Further, lime includes slaked lime and quick lime, and either of them can be used.

However, the four-component composition of Portland cement, calcium aluminate, gypsum fine powder, and lime is insufficient in terms of long-term durability after steam curing. It was found that by further adding fine slag powder to this system, the strength at the time of demolding can be increased, and the strength enhancement after steam curing and long-term durability as a building material can be secured.

The slag fine powder used in the present invention is disclosed in Japanese Patent Application No. 59-261083.
In the slag fine powder proposed in No. 1, a slag fine powder having a Blaine specific surface area of 6,000 to 12,000 cm ² / g obtained by a classification method from an ordinary slag powder having a Blaine specific surface area of about 4,000 cm ² / g. is there. When using a normal slag powder, there is almost no strength increase after steam curing, but in the case of the slag fine powder used in the present invention, with respect to 100 parts by weight of Portland cement, at an amount of 20 to 350 parts by weight used. If so, the strength can be greatly improved by steam curing, and
Greater strength enhancement after steam curing.

The aggregate used in the present invention is an aggregate having a maximum particle size of 2,000 μm or less, and either an inorganic aggregate or an organic aggregate can be used. If aggregates containing particles with a maximum particle size of 2,000 μm or more are used, the adhesion between the reinforcing fibers and the cement matrix is obstructed, and the bending and reinforcing effect of the fibers cannot be improved. It becomes necessary to increase the amount added, and as a result, the fluidity of the resulting slurry decreases, making molding extremely difficult. The amount of aggregate used is 5 to 140 parts by weight, preferably 10 to 80 parts by weight, based on 100 parts by weight of the five-component mixture of Portland cement, calcium aluminate, gypsum, lime and slag fine powder. It is a department. Examples of the inorganic aggregate include foamed lightweight aggregates such as mesalite, shirasu balloon, and perlite, and anti-fire stone, limestone, fly ash,
Slag, zeolite, etc. can be used, and as the organic aggregate, for example, wood, pulp, styrene foam, etc. can be used. Details are as shown in the examples.

Next, the molding method and curing method of the slurry of the present invention will be described. As the molding method, any known method other than the papermaking method can be applied and is not particularly limited. For example, there are a casting method, a pressure molding method, and an extrusion molding method.

The feature of the molding method of the present invention is that, in any of the above-mentioned molding methods, when molding the kneaded slurry, a vibration frequency of 100 to 10,000 VPM is added to the slurry, and coarse bubbles are entrained during kneading. Is removed, and the fluidity of the slurry is increased. Further, it has a great feature in that coarse air bubbles floating due to vibration are removed by blowing compressed air. The temperature of the compressed air may be room temperature, but warm air of 40 to 60 ° C is preferable. Details are shown in the examples. The amount of water in the slurry is
Depending on the molding method, the amount of water suitable for the molding method can be appropriately selected. The slurry of the present invention is molded 3
Can be set and hardened in ~ 60 minutes and can be immediately demolded and processed.

Next, the cured product that has been demolded and processed within 3 to 60 minutes after molding is
Perform steam curing at 90 ℃ or below and 150 ℃ ・ hr or above.
When the steam curing temperature exceeds 90 ° C, ettringite is decomposed, and at steam curing at 150 ° C / hour or less, calcium silicate hydrate is not sufficiently formed and a hardened body is not formed. Further, when the temperature is 10 ° C. or higher, a cured product can be produced by aging for a long time by natural curing.

The method of mixing the bubbles may be either a preforming method in which the bubbles are created in advance, or a mix forming method in which a foaming agent is added at the same time when the slurry is prepared to foam. As the foaming agent, any commercially available foaming agent can be used and is not particularly limited. However, an aluminum powder-based inorganic foaming agent is not preferable because it reacts with gypsum. If necessary, a bubble stabilizer such as carboxymethyl cellulose (CMC) or polyvinyl alcohol (PVA) can also be used.

The reason for introducing the bubbles is not only for the purpose of reducing the weight of the cured product, but also for the effect of alleviating the expansion pressure due to the formation of ettringite after curing and preventing the occurrence of cracks. The amount of air bubbles mixed in is such that the air-dry specific gravity of the cured product is 0.4 to 1.5.
It is important to set the amount necessary to That is,
This is because when the air-dry specific gravity is 1.5 or more, the properties as a lightweight building material are lost, and when the air-dry specific gravity is 0.4 or less, the cured product has low strength and a large amount of water absorption.

Next, as the reinforcing fiber used in the present invention, any synthetic fiber typified by vinylon fiber, carbon fiber, alkali resistant glass fiber, rock wool, or asbestos can be used as long as the hard and hard effect is enhanced. .

<< Examples >> The materials and abbreviations used in this example are as shown in Table 1.

From the chemical composition and the diffraction X-ray analysis, it is estimated that the mineral composition of DENKA ES is about 49% amorphous calcium aluminate, about 49% CaSO ₄ and about 2% other.

Example-1 Example-1 investigates the influence of the blending ratio of the quick-hardening cement composition and the addition amount of citric acid on the setting and hardening property of the slurry. That is, No. 1 shown in Table 2
About 9 kinds of fast-setting cement compositions of No. 9 were kneaded by hand for 30 seconds at a water powder ratio of 60%, a thermocouple was immediately inserted, and the time immediately after water injection until the temperature rises was measured. It was set as the start time of condensation. In addition, the properties of the cured product were observed.
The results are shown in Table 3.

In Comparative Example No. 1, the setting start time is extremely short, cracks are generated and curing is poor, and it cannot be used. Further, Comparative Examples No. 2 and No. 3 have no problem in the setting start time, but the strength development of the cured product is poor, or expansion cracks occur, which is suitable for the method for producing the lightweight cured product of the present invention. There is no composition.

No. 4 to No. 9, which are the present invention, have a setting start time of about 17 to 25.
The composition is suitable for the method for producing a light-weight cured product of the present invention, in which the pot life from kneading to molding can be appropriately taken, and the cured product exhibits good strength and does not crack. It is a thing. Further details. Comparing No. 4 and No. 5, condensation start time differs depending on the water temperature used, and the condensation start time becomes longer as the water temperature becomes lower. No. 6 added with 5% of slaked lime shows almost the same setting start time as No. 4 even though the water temperature is as low as 8 ° C. Also, comparing No. 4 and No. 7, it was found that the condensation start time was almost the same, and even if there was a difference in water temperature, it was possible to make the condensation start time the same by the addition amount of citric acid. Shows. From these, it can be seen that even when the outside air temperature or the water temperature fluctuates, the setting start time can be controlled by appropriately adding slaked lime and increasing or decreasing the amount of citric acid added. In addition, No. 8 containing 5% anhydrous gypsum and No. 9 containing 5% slaked lime and 5% anhydrous gypsum have normal setting start times and cured properties.

Example-2 In Example-2, the particle size and the amount of the aggregate that can be used in the present invention are investigated.

In Example-2, good results were obtained in Example-1.
Using No. 4 quick-setting cement composition, with respect to 100 parts by weight of the quick-setting cement composition, citric acid 0.3 part by weight, water reducing agent 1.0 part by weight, foam stabilizer 0.16 part by weight, vinylon fiber 1.8
Parts by weight, 5 to 200 parts by weight of various aggregates, and water 70 to 8
5 parts by weight was added, and an appropriate amount of bubbles prepared by the preforming method was added to the mixture, which was kneaded for 2 minutes with an omni mixer to prepare a slurry. This slurry is poured into a 40 × 40 × 160 mm mold and molded, and after about 40 minutes, it is demolded and then 70 ° C.
Then, steam curing was performed for 7 hours to prepare a light-weight cured body. This lightweight cured product was dried at 60 ° C. for 24 hours and various physical property tests were conducted. The results are shown in Table 4.

Comparative Example No. 1, which does not use aggregate, has a high bending ratio strength and is good, but a large number of microcracks were generated when exposed outdoors. Comparative examples No. 2 (Perlite M2), No. 3 and 4 (Mesalite MS2.5), which use aggregates with a maximum particle size of 2,000 μm or more, have smaller dimensional changes than Comparative Example No. 1. Although it is small and the number of microcracks is also small, the bending ratio strength is reduced to about half as compared with Comparative Example No. 1. On the other hand, No. using the aggregate of the present invention having the maximum dimension of 2,000 μm or less.
Nos. 5 to 17 have a small decrease in bending ratio strength and suppress the occurrence of microcracks. Further details. If you use a very light aggregate pearlite (M4) and Shirasu balloons (BO _3), only about 10 parts by weight with respect to fast-curing cement compositions 100 parts by weight, the slurry of the flowability and moldability of the work It cannot be used due to its nature. In addition, mesalite (MS1.
In the case of 2), microcracks decrease as the amount of use increases, but in view of the degree of decrease in bending specific strength, it is preferably 100 parts by weight or less relative to 100 parts by weight of the quick-setting cement composition. No. 1 which uses fly ash (FA) and filler (FI), which are powders and have poor hydration reactivity, as aggregates
Nos. 2 to 17 suppress the occurrence of microcracks, and even when used up to 140 parts by weight with respect to 100 parts by weight of the fast-setting cement composition, the degree of decrease in bending specific strength is small.

From the above experimental results, the aggregate used in the present invention has a maximum particle size of 2,000 μm or less, and a fast-setting cement composition 1
The amount is limited to 5 to 140 parts by weight with respect to 00 parts by weight.

Example-3 In Example-3, a method for removing coarse bubbles (having a diameter of about 1 mm or more) entrained during slurry kneading and molding in producing a full-scale panel was tested in a practical-scale experimental plant shown in FIG. is there. This experimental plant consists of a hopper 1 for supplying a powder / fiber mixture obtained by premixing a fast-setting cement composition with vinylon fibers and aggregates, a continuous metering and supplying device 2, a foaming machine 5, a bubble stabilizer, A tank 4 for supplying an aqueous solution containing a predetermined amount of a water reducing agent and citric acid, and a powder fiber mixture supplied from a powder fiber charging port 6a and an aqueous solution supplied from an aqueous solution charging port 6b and a bubble charging port 6c. It comprises a pin mixer 6 for kneading air bubbles to continuously produce a slurry, a vibrator 7 for continuously vibrating the slurry discharged from the pin mixer 6, and a nozzle 8 for injecting compressed air to the slurry.
The position where vibration is applied to the slurry and the position where the compressed air is injected are not limited to the positions shown in FIG. 1, and any position that is effective in improving the fluidity of the slurry and removing coarse bubbles can be used. Good.

The compounding ratios of the various materials tested in Example-3 are the same as No.15 of Example-2. That is, 100 parts by weight of a fast-setting cement composition, 1.8 parts by weight of vinylon fiber and a filler.
Using a mixture obtained by premixing 60 parts by weight of materials, a foam stabilizer, a water reducing agent, and citric acid were prepared in the same manner as in Example 3 to prepare an aqueous solution. The water was set to 75 parts by weight with respect to the parts.

Under these conditions, the slurry continuously kneaded and discharged was cast into a mold having a thickness of 30 mm, a width of 900 mm and a length of 1,800 mm. At this time, the molding method differs depending on whether the slurry is vibrated or not, when compressed air is blown, and when both vibration and compressed air are used together.
A variety of panels were made. This panel was demolded after 30 to 60 minutes, and then steam curing at 70 ° C. for 7 hours and then hot air drying at 60 ° C. for 12 hours to obtain a fiber-reinforced slag gypsum cement-based lightweight cured product.

Both sides of the panel thus obtained were polished to examine the number of coarse bubbles (1 to 3 mm in diameter, 3 mm or more). Result 5
It is shown in the table.

From this result, it is apparent that applying vibration to the slurry and blowing compressed air as a method for removing coarse bubbles are extremely effective means.

<< Effects of the Invention >> As shown in the examples, according to the method for producing a lightweight cured product of the present invention using a slag gypsum cement-based fast-setting cement composition, the slurry is set and hardened in a short time,
It can be demolded immediately, and after that, by general steam curing,
A light-weight cured product can be commercialized in a short period of time, and the outer wall material and inner wall material excellent in fire resistance, water resistance and durability, which have a large degree of freedom in thickness, shape, etc., can be provided at low cost. The effect of the invention can be said to be extremely large.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an experimental plant in which an experiment was carried out on a method of removing coarse bubbles. 1 ... Hopper, 2 ... Metering and feeding device 4 ... Tank, 5 ... Foaming machine 6 ... Pin mixer, 6a ... Powder fiber inlet 6b ... Aqueous solution inlet, 6c ... Bubble inlet 7 ... Vibrator, 8 ... Nozzle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C04B 22:14 20:00) (73) Patent holder 999999999 Obayashi Corporation Kitahama, Chuo-ku, Osaka City, Osaka Prefecture East No. 33 (72) Inventor Katsuyoshi Imaizumi 5-19-12 Shimotakaido, Suginami-ku, Tokyo (72) Inventor Miki Aoyama 3-6-8 Sumiyoshi-cho, Hoya-shi, Tokyo (72) Inventor Nagao Hori Saitama Prefecture 981-13 Yamaguchi, Tokorozawa-shi (72) Inventor Katsumi Takenan 67-14 Gomigaya, Tsurugashima-cho, Iruma-gun, Saitama Prefecture (72) Inventor Kiyobuchi Kiyo 22-22, Shirattoridai, Midori-ku, Yokohama, Japan Yoichi Ishikawa Tokyo 1-8-12 Megurohonmachi, Meguro-ku, Tokyo (72) Inventor Seiji Kazama 2-5-19 Midoridai, Kawanishi-shi, Hyogo Prefecture (72) Atsuji Nasu 6-13 Omori-cho, Nishinomiya-shi, Hyogo Prefecture

Claims (9)

(57) [Claims] 1. A slag fine powder of 20 to 350 parts by weight, lime of 0 to 20 parts by weight, and a total amount of calcium aluminate and gypsum fine powder of 20 to 100 parts by weight of Portland cement.
To 100 parts by weight, and 5 to 140 parts by weight of an aggregate having a maximum particle size of 2,000 μm or less is added to the mixture having a weight ratio of gypsum fine powder and calcium aluminate of 0.5 to 2.0, And 0.01-1.5 parts by weight of a setting regulator is added to the mixture, a slurry is prepared by mixing water, air bubbles and reinforcing fibers, and after demolding, steam-cured fiber-reinforced slag gypsum cement. Method for producing a light-based cured product. 2. The slag fine powder is a slag fine powder obtained by crushing granulated blast furnace slag and then classifying it, and the fineness thereof is 6,000 to 12,000 cm ² / g in terms of Blaine specific surface area. A method for producing a fiber-reinforced slag gypsum cement-based lightweight cured product according to claim 1. 3. The calcium aluminate is CA, CA
_2. Any one of C ₂ , C ₃ A, C ₁₂ A ₇ , C ₁₁ A ₇ and CaF ₂ or a mixture of two or more thereof, and the total content of these is 50% or more. A method for producing the fiber-reinforced slag gypsum cement-based lightweight cured product described. 4. The gypsum fine powder has a fineness of 2,500 cm ² / g or more in terms of Blaine specific surface area, and has a 88 μ sieve residue.
It is 0.5 or less, The manufacturing method of the fiber reinforced slag gypsum cement type lightweight hardening body of Claim 1 characterized by the above-mentioned. 5. The method for producing a fiber-reinforced slag gypsum cement-based light weight cured product according to claim 1, wherein when the slurry is molded, a vibration having a frequency of 100 to 10,000 VPM is applied to the slurry. 6. The method for producing a fiber-reinforced slag gypsum cement-based light weight cured product according to claim 1, wherein compressed air is blown to the slurry when the slurry is molded. 7. The method for producing a fiber-reinforced slag gypsum cement-based light weight cured product according to claim 1, wherein the slurry is set and hardened within 3 to 60 minutes after molding, and can be immediately demolded and processed. 8. A steam curing temperature of 90 ° C. or lower and 150 ° C.
The method for producing a fiber-reinforced slag gypsum cement-based lightweight cured product according to claim 1, wherein the curing is performed for at least an hour. 9. The method for producing a fiber-reinforced slag gypsum cement-based lightweight cured product according to claim 1, wherein the cured product has an air-dry specific gravity of 0.4 to 1.5.