JP2001097784A - Light concrete compact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light concrete compact excellent in dimensional stability and strength. SOLUTION: This light concrete compact is characterized in that it is added with calcium carbonate of whiskery aragonite type, an aluminum compound having >=2 cal heat release amount/1 g of powder when immersed in water and a water soluble calcium compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight cement molding used as a building material for an outer wall or the like.

[0002]

2. Description of the Related Art Conventionally, it is known that lightweight cement moldings used as building materials are manufactured by various molding methods such as a papermaking method, a pressing method, and an extrusion method. In general, these lightweight cement molded articles are made of inorganic lightweight aggregates such as pearlite, glass balloons, and shirasu balloons, and organic lightweight bones such as styrene beads in order to reduce the specific gravity or the dimensional change rate due to the absorption and release of moisture. Materials are added.

However, the use of a large amount of these lightweight aggregates causes the strength of the molded article to be impaired, and also impairs the workability such as nailing and sawing properties. In the case of a material, a problem often arises in nonflammability.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional lightweight cement molded product, and is characterized in that a whisker-like aragonite-type calcium carbonate is mixed with an aluminum compound having a calorific value of a certain value or more. From the cement composition used with calcium compounds soluble in water,
This has been completed based on the knowledge of the present inventors that a lightweight cement molded article having excellent physical properties such as strength can be obtained. It is an object of the present invention to provide a lightweight cement molded article having more excellent dimensional stability and strength than a conventional lightweight cement molded article.

[0005]

In order to achieve the above object, a lightweight cement molded article according to the present invention according to claim 1 is provided.
It is characterized by adding a whisker-like aragonite-type calcium carbonate, an aluminum compound having a calorific value of 2 cal / g or more of powder when immersed in water, and a calcium compound soluble in water. Further, the lightweight cement molded article of the present invention according to claim 2 is characterized in that, in the lightweight cement molded article according to claim 1, a monocarbonate hydrate is formed by the whisker-like aragonite-type calcium carbonate. Is what you do.

[0008] The lightweight cement molded article of the present invention according to claim 3 is characterized in that, in the lightweight cement molded article according to claim 1 or 2, the whisker-like aragonite-type calcium carbonate is immersed in water at 1 to 5% by weight. Has a calorific value of 2 cal /
It is characterized in that 2 to 15% by weight of an aluminum compound, which is 1 g or more of powder, and 0.5 to 5% by weight of a water-soluble calcium compound are added.

[0007] In the present invention, the cement is not particularly limited. For example, portland cement such as ordinary portland cement and early-strength portland cement, blast furnace cement, silica cement, mixed cement such as fly ash cement, and special cement such as alumina cement. Cement can be used.

In the present invention, whisker-like aragonite-type calcium carbonate is used because if whisker-like aragonite-type calcium carbonate having characteristics such as needle-like particles having a diameter of about 20 μm is used among calcium carbonates, high strength and light weight can be obtained. This is because a cement molding can be obtained.
This is because monocarbonate (3CaO.multidot.3) is formed from a whisker-like aragonite-type calcium carbonate, an aluminum compound having a calorific value of 2 cal / g of powder or more when immersed in water, and a calcium compound soluble in water.
It is presumed that Al2O3.CaCO3.11H2O) is formed following the shape of calcium carbonate, becomes whisker-like, reinforces the hardened cement, and exhibits high strength. The whisker-like aragonite-type calcium carbonate is commercially available, for example, under the trade name “Tamapearl TP- # 123” manufactured by Okutama Industry Co., Ltd., and is available.

An aluminum compound having a calorific value of 2 cal / g of powder or more when immersed in water has a calorific value of 2 cal / g or more per gram of powder when immersed in water at ordinary temperature, and is reactive with water. It is an aluminum compound, and a preferable calorific value is 5 cal or more and about 100 cal or less. If the calorific value is smaller than this, the effect of shortening the hardening time when added to cement is reduced. There is no upper limit for the calorific value since the curing time can be shortened as the calorific value increases, but if the calorific value is too large, the working time cannot be secured.

The calorific value of the aluminum compound was determined by immersing the aluminum compound in a ratio of 20 g of water to 20 g of water at room temperature, stirring the mixture for 6 minutes, and measuring the calorific value with a calorimeter. The calorific value was integrated, and this value was defined as the calorific value of the aluminum compound. As the aluminum compound having a calorific value of 2 cal / g of powder or more when immersed in water, industrial products such as hydraulic alumina and alumina cement can be used.

Examples of the water-soluble calcium compound include calcium hydroxide (hydrated lime), calcium oxide (quick lime), calcium silicate, and Portland cement used in the present invention.

In the present invention, the calorific value when immersed in whisker-like aragonite-type calcium carbonate and water is 2c
al / an aluminum compound of 1 g or more in powder, and
A preferable addition ratio of the water-soluble calcium compound is such that the calcium carbonate is 1 to 5% by weight, and the aluminum compound is a light-weight cement molded product obtained by reacting water with a cement composition containing the cement compound and the like. Is 2
15% by weight, and 0.5 to 5 of the calcium compound
% By weight. The whisker-like aragonite-type calcium carbonate, the aluminum compound, and the proportion of the calcium compound are each out of these ranges,
The amount of monocarbonate hydrate is too small or too large, and sufficient strength is not exhibited.

The mixing ratio of the whisker-like aragonite-type calcium carbonate, the aluminum compound having a calorific value of 2 cal / g of powder or more when immersed in water, and the calcium compound soluble in water are monocarbonate hydrate ( 3
In order to obtain CaO.Al2 O3 .CaCO3 .11H2O) efficiently, the number of calcium atoms contained in the calcium compound / the number of aluminum atoms contained in the aluminum compound is preferably from 0.1 to 1.0, and In order to obtain excellent durability, it is preferable that the carbonate ion (CO3) of calcium carbonate / the number of aluminum atoms of the aluminum compound is 0.1 to 1.0.

If the content of the thermosetting component is out of this range and the content of the thermosetting component in the cement is too small and the content of the Portland cement is too large, the hardening reaction of the cement does not proceed so much in hot pressing, for example. If the strength is not sufficient to release from the press mold, the content of the thermosetting component is too high, and the content of Portland cement is too low, the curing reaction is too fast Work time cannot be obtained, and on the other hand, the raw material cost may increase.

In the cement composition constituting the lightweight cement molding of the present invention, a filler such as silica sand, silica sand powder, diatomaceous earth or the like may be substituted for a part of the cement. In the lightweight cement molded body of the present invention,
In addition to the calcium carbonate, the aluminum compound and the water-soluble calcium compound according to the first aspect, it is necessary to take measures for realizing weight reduction such as addition of a lightweight aggregate. As the lightweight aggregate, for example, perlite, shirasu balloon, fly ash balloon, trade name "Espheres" manufactured by Taiheiyo Cement Co., Ltd., inorganic lightweight aggregate such as glass balloon, styrene beads, organic lightweight aggregate such as polyethylene balloon are used. Is done. Among these lightweight aggregates, a lightweight aggregate having a small dimensional change due to a change in dry or wet moisture is preferably used.

As the inorganic lightweight aggregate, those having a water absorption of less than 5% can be suitably used. By adding such an inorganic lightweight aggregate, the obtained cement molded body is reduced in weight and excellent in dimensional stability and freeze-thaw property. Examples of the inorganic lightweight aggregate include a shirasu balloon, a fly ash balloon, "E-Spheres" (manufactured by Taiheiyo Cement Corporation), and a glass balloon.

In the lightweight cement molded product of the present invention, the preferable addition ratio of the lightweight aggregate and water is as follows.
100 parts by weight, 10-60 parts by weight of lightweight aggregate, 3 parts of water
It is performed at 0 to 70 parts by weight.

If the amount of the lightweight aggregate is less than 10 parts by weight, the specific gravity increases and the weight of the cement board increases. On the other hand, when the amount is more than 50 parts by weight, the amount of cement as a binder decreases, and the strength decreases.

If the amount of water is less than 30 parts by weight, the hydration reaction of the cement becomes insufficient and the strength is reduced. When the amount is more than 70 parts by weight,
Small agglomerates are formed, mixing cannot be performed uniformly, and the formed lightweight cement molded product is inhomogeneous and loses strength.

As a method for producing the lightweight cement molded product of the present invention, for example, a whisker-like aragonite-type calcium carbonate, the calorific value when immersed in water is 2 cal / powder 1
g or more of the aluminum compound, water-soluble calcium compound cement, lightweight aggregate, and a mixture of water were sprayed and dropped on the formwork, deposited, and hardened by pressurizing and heating for a predetermined time by a hot press. Later, a method of demolding may be mentioned. The mixture can be prepared by a known method, for example, using an omni mixer, a Henschel mixer, or the like.

[0021]

EXAMPLES (Examples 1 and 2 and Comparative Examples 1 and 2) Lightweight cement moldings of the present invention and comparative samples having the compositions shown in Table 1 were produced. In Example 1, 83.4 parts by weight of fast-strength Portland cement (manufactured by Taiheiyo Cement), 7.9 parts by weight of alumina cement (manufactured by Denka No. 2 Denki Kagaku), and whisker-like aragonite-type cement composition in Example 1. Premixed with 4.7 parts by weight of calcium carbonate ("Tamapearl TP- # 123" manufactured by Okutama Kogyo Co., Ltd.) and 3.2 parts by weight of slaked lime (Komagata Lime Co., Ltd.). 92.0 parts by weight (manufactured by Taiheiyo Cement Corporation), 4.0 parts by weight of alumina cement (manufactured by Denka No. 2 Denki Kagaku), 2.4 parts by weight of calcium carbonate, slaked lime (manufactured by Komagata Lime Industry Co., Ltd.) 1.6 Using a pre-mixed part by weight, as a lightweight aggregate, a fly ash balloon ("CF beads")
Union Chemical Co.) was used.

In the comparative examples, the formulations were as shown in Table 1. However, as the calcium carbonate, a plate-like calcite type manufactured by Wako Pure Chemical Industries, Ltd. was used.

The heat value of the aluminum compound is as follows:
g at 25 ° C. in 20 g of distilled water.
Calorimeter (Tokyo Riko, Model M
MC-5320), and this value was used as the calorific value. In the production of the lightweight cement molding, the cement composition, the lightweight aggregate and the water were mixed using a Henschel mixer. Thereafter, the resin was cured by pressurizing and heating with a hot press for a predetermined time, and then released from the mold to obtain a lightweight cement board.

Each of the above cement plates was tested for bending strength, change in water absorption length, specific gravity, water absorption, and freeze-thaw performance. The flexural strength was measured on a one-week-old sample according to JIS A1408. Regarding the change in water absorption length, the obtained lightweight cement board was 150 mm long and 50 mm wide.
After being cut into a dumbbell shape of 1 mm, dried at 60 ° C. for 1 day, and immersed in water for 1 day, the dimensions were measured with a micrometer, and the rate of change in water absorption length was calculated from the following equation. Water absorption length change rate (%) = (dimension after immersion in water-dimension after initial drying) / dimension after initial drying x 100

The specific gravity was evaluated based on the absolute dry specific gravity after drying at 105 ° C. for 24 hours. For water absorption, see JI
Performed according to SA5403. The freeze-thaw performance was evaluated according to AST MC666A, and changes in appearance such as cracks were visually observed and evaluated according to the following criteria. ：: No cracking △: Some cracking ×: Large cracking

From Table 2, it is clear that the lightweight cement board of the present invention is excellent in strength, dimensional stability, freeze-thaw property, and lightweight. On the other hand, the sample of Comparative Example 1 was not sufficiently cured after hot pressing and could not be released from the mold. The sample of Comparative Example 2 is inferior in strength and dimensional stability.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

The lightweight cement molded article of the present invention is constituted as described above, and is excellent in dimensional stability, durability and strength as compared with conventional lightweight cement molded articles.

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Claims (3)

[Claims] 1. A whisker-like aragonite-type calcium carbonate having a calorific value of 2 cal / g of powder when immersed in water.
A lightweight cement molded product comprising the above aluminum compound and water-soluble calcium compound. 2. The lightweight cement molded product according to claim 1, wherein a monocarbonate hydrate is formed by the whisker-like aragonite-type calcium carbonate. 3. A whisker-like aragonite-type calcium carbonate of 1 to 5% by weight having a calorific value of 2c when immersed in water.
al / aluminum compound weighing 1 g or more is 2-1.
5% by weight and 0.5% of a water-soluble calcium compound
The lightweight cement molded product according to claim 1 or 2, wherein about 5% by weight is added.