JPH0796471B2 - Bubble concrete manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is characterized in that a CaO-containing mineral powder is blended with a rapid-hardening slurry as a regulator of an aerated concrete production method, particularly as an initial setting time of the rapid-hardening foam slurry. The present invention relates to a method for producing aerated concrete.

[Prior art and its problems] ALC is a typical example of cellular concrete, which contains crystalline calcium silicate hydrate (tobermorite group) as a main component obtained by curing a foam in an autoclave at high temperature and high pressure. Is.

ALC manufacturing methods are roughly classified into a post-form method in which bubbles are generated by utilizing a water-gas reaction of metal powder and a pre-form method in which bubbles are blown into a hydraulic slurry.

The preform method is a method of mixing a foam produced by previously foaming a foaming agent and cement paste or mortar, and a concrete example is as follows.

First, bubbles generated by a foaming agent are blown into a hydraulic slurry composed of Portland cement, silica sand powder, a lime-based admixture, etc. to obtain a hydraulic foam slurry. Further Ca
A rapid-curing slurry of alumina cement containing O.Al ₂ O ₃ as a main component is mixed to form a rapid-curing foam slurry, which is then cast into a mold. Alumina cement is contained in this rapid-curing foamed slurry, so that the foamed hardened body is obtained by fixing the air bubbles before they disappear. This is a method in which the foamed cured body is deframed and then cured at high temperature and high pressure in an autoclave to obtain aerated concrete. However, in this method, one mold is required for one slab, and therefore it is necessary to accelerate the rotation of the mold in order to improve productivity. It is essential to adjust the initial curing time from the casting to the removal of the frame, and it is necessary to set the initial curing time suitable for each production process.

It was possible to adjust the initial curing time to some extent by increasing or decreasing the addition amount of CaO.Al ₂ O ₃ -based alumina cement used in the conventional rapid hardening slurry.

However, when the amount of alumina cement is increased and the initial curing time is shortened, the deframed strength of the foamed cured product increases with the increase in the amount of alumina cement, but the transition of alumina cement hydrate during high temperature and high pressure curing by an autoclave. As a result, the strength is significantly reduced, and it is preferable that the amount of alumina cement added is small from the viewpoint of strength.

On the contrary, when the amount of alumina cement is reduced, the initial curing time becomes longer, but it is difficult for air bubbles to be fixed inside the cured body,
Due to defoaming, the physical properties of aerated concrete such as lightness, heat insulation and sound insulation were deteriorated.

From the above, since the amount of alumina cement used in the rapid hardening slurry is necessarily limited, the range of adjustment of the initial setting time is narrow, and the initial setting time suitable for each production process cannot be obtained.

For this reason, it is not possible to adjust the delicate consistency that requires capping, patterning, etc. during initial curing, and the final product, for example, the panel surface processing surface, cannot be complicated, and design processing etc. is hindered. It was

As a result of various studies to eliminate the drawbacks of the conventional techniques, the present inventors used a CaO-containing mineral in the method of producing aerated concrete by the preform method, and adjusting the initial time of the rapid-hardening foam slurry is sufficient. Secure enough strength,
It can be adjusted to the optimum even for delicate consistency such as capping and patterning, and therefore volume stability,
The present invention has been completed based on the knowledge that an aerated concrete having excellent closed cell properties can be efficiently produced.

[Means for solving problems]

That is, the present invention, a hydraulic slurry comprising a cement mixture and water, a rapid hardening slurry consisting of alumina cement and water and water bubbles are mixed to prepare a rapid hardening foamed slurry,
Casting, in the method for producing aerated concrete obtained by curing at high temperature and high pressure after molding, as a modifier of the initial setting time of the rapid-hardening foam slurry, CaO-containing mineral powder is characterized by blending into the rapid-hardness slurry It is a concrete manufacturing method.

The details of the present invention will be described below.

The cement composition according to the present invention comprises cement, silica sand powder, a lime-based admixture, and the like, and if necessary, for example, a carboxylic acid-based, phosphoric acid-based, lignin-based dispersant, etc. may be added. it can.

Examples of the cement include ordinary, early strength, ultra-early strength Portland cement and the like.

Further, the silica sand powder is not particularly limited, but preferably has a Blaine value of 2,000 to 6,000 cm ² / g, and S
It is preferable that the iO ₂ content is 90% or more.

Further, as the lime-based admixture (hereinafter referred to as admixture), those which are usually used may be used, but those consisting of slaked lime 30 to 100 parts by weight and gypsum 70 to 100 parts by weight are preferable, and gypsum is type II anhydrous gypsum. Is more preferable.

The above materials may be blended as necessary, for example,
Portland cement 50-150 parts by weight, silica sand powder 50-1
A blending amount of 50 parts by weight and 0 to 20 parts by weight of the admixture is preferable from the viewpoint of strength of the final product.

The amount of the dispersant added is preferably 0 to 5 parts by weight with respect to 100 parts by weight of Portland cement.

A hydraulic slurry comprising a cement mixture and water is a mixture of the above materials and water, and the amount of water is preferably 100 to 150 parts by weight with respect to 100 parts by weight of the cement mixture,
It is preferable to stir with a fluid mixer to form a slurry having a viscosity of about 1,000 to 20,000 psi.

Alumina cement (hereinafter referred to as AC) in the present invention means
AC containing CaO / Al ₂ O ₃ (hereinafter referred to as CA) as a main component, which is synthesized from an alumina source such as bauxite or Bayer alumina and a calcia source such as quicklime or limestone by a firing method and / or a melting method. The clinker was crushed with a crusher such as a ball mill or a roller mill, and powder X
The CA content determined by the line diffraction method is 60% by weight or more.

Explaining the production method further, for example, CaO _{30 to} 40 wt%, Al ₂ O ₃ 40 to 60 wt% by blending an alumina source and a calcia source, the clinker synthesized by the above-mentioned method Brane 3,000 ~ It can be manufactured by crushing to 7,000 cm ² / g. Particularly, AC produced by the melting method is preferable because of its high hydration activity.

The CaO-containing mineral in the present invention is composed of hydraulic calcium aluminate (hereinafter referred to as hydraulic CA) and non-hydraulic mineral.

Hydraulic CA means 3CaO ・ Al ₂ O ₃ , 12CaO ・ 7Al ₂ O ₃ , CaO ・ 2Al
₂ O ₃ , 5CaO ・ 3Al ₂ O ₃ , 3CaO ・ 5Al ₂ O ₃ and 4CaO ・ Al ₂ O ₃・ Fe
₂ O ₃ (C ₃ A, C ₁₂ A ₇ , CA ₂ , C ₅ A ₃ , C ₃ A ₅ and C ₄ AF
Etc.) and the like, and after synthesizing from an alumina source such as bauxite or Bayer alumina, a calcia source such as quicklime or limestone, and an iron source such as red mud or iron oxide by a melting method and / or a firing method, a ball mill or It is crushed by a crusher such as a roller mill. Particularly, C ₃ A, C ₁₂ A ₇ , CA ₂ , C ₅ A ₃ and C ₃ A _{5 which} are synthesized by a melting method are preferable because of high hydration activity, and C ₄ AF is obtained by a calcination method. What was synthesize | combined about this is preferable.

The crystallization rate of hydraulic CA is preferably 20 to 80%, more preferably 40 to 70%.

The crystallization rate here is obtained by measuring the diffraction intensity of each hydraulic CA mineral by a powder X-ray diffraction method, and is calculated by the following equation.

If the crystallization rate is less than 20%, the curing adjustment effect will be severe,
It is not preferable because it is difficult to adjust the subtle consistency. On the other hand, if it is more than 80%, the effect of adjusting the curing is poor, which is not preferable.

C ₃ A, the _{C 12 A 7, C 5 A} 3 and C ₄ Initial setting time when blending the AF can be shortened. Particularly, C ₁₂ A ₇ is preferable from the viewpoint of easy adjustment.

Also, when CA ₂ and C ₃ A ₅ are blended, the initial curing time can be lengthened. In particular, CA ₂ is preferable because it can be easily adjusted.

The specific surface area of the hydraulic CA is preferably 3,000 cm ² / g or more in Blaine value, 4,000~6,000cm ² / g is more preferable. 3,000 cm
If it is less than ² / g, the effect of adjusting the hardening of the rapid-curing foamed slurry is poor, and the fluidity is poor and the casting time is short and the strength when deframed is insufficient, and the foamed cured body is likely to be damaged. Not preferable.

The non-hydraulic mineral referred to in the present invention means CaO · TiO ₂ , 2CaO · Al ₂
O ₃・ SiO ₂ , CaO ・ Al ₂ O ₃・ 2SiO ₂ , CaO ・ MgO ・ 2SiO ₂ , CaO
・ Fe ₂ O ₃ and CaO ・ 6Al ₂ O ₃ (CT, C ₂ AS, CAS ₂ ,
CMS ₂ , CF and CA ₆ ) etc., and it is essential to include CaO content in the mineral composition. When these non-hydraulic minerals are blended, the initial setting time can be lengthened without lowering the strength after curing in an autoclave. This non-hydraulic mineral is a calcia source such as quicklime or limestone, an alumina source such as bauxite or Bayer alumina, a silica source such as silica stone or fused silica, a titania source such as titanium oxide, an iron source such as red mud or iron oxide, and From the magnesia source such as magnesite, the melting method and /
Alternatively, it is synthesized by a firing method and then pulverized by a pulverizer such as a ball mill or a roller mill, and the crystallization rate of each is preferably 80% or less, more preferably 40 to 70%. If the crystallization rate is higher than 80%, the strength remains as an inert filler in the final product even after curing at high temperature and high pressure in an autoclave, which is not preferable.

Further, the specific surface area is preferably 3,000 cm ² / g or more in Blaine value, 4,000~6,000cm ² / g is more preferable. If it is less than 3,000 cm ² / g, the fluidity of the rapid-curing foamed slurry is poor, the casting time is short, the strength at the time of deframing is insufficient, and the foamed cured body is easily damaged, which is not preferable.

The mixing ratio of CaO-containing mineral is 10 to 300 per 100 parts by weight of AC.
Parts by weight are preferred. In particular, hydraulic CA C ₃ A, C ₁₂ A ₇ , C
_{20 to} 200 parts by weight is more preferable in the case of A ₂ , C ₅ A ₃ and C ₃ A ₅ , and 10 to 200 parts by weight in the case of non-hydraulic minerals CA ₆ and C ₂ AS, CT, CAS ₂ , CMS. ₂ and CF are more preferably 20 to 200 parts by weight. If the amount of CaO-containing mineral is less than 10 parts by weight, the effect of adjusting the initial curing time is poor, and if it exceeds 300 parts by weight, the effect is too great. Therefore, the delicate consistency such as patterning on the surface of the final product is adjusted. Is not preferable because it becomes difficult.

These hydraulic CA and non-hydraulic minerals can be blended in AC alone or in combination.

Hydraulic CA10 when using hydraulic CA and non-hydraulic minerals together
25-100 parts by weight of non-hydraulic mineral is preferable to 0 parts by weight in terms of curing adjustment and consistency adjustment.

When used in combination, each may be mixed as a powder, or each synthesized mineral may be mixed and pulverized. Further, it may be crushed after the synthesis in a predetermined amount.

If necessary, 0 to 5 parts by weight of a carboxylic acid-based, phosphoric acid-based or lignin-based dispersant may be added to 100 parts by weight of AC.

The mixing ratio of cement mixture and AC is 80-95 for cement mixture.
20 to 5 parts by weight of AC is preferable with respect to parts by weight.

If the AC amount exceeds 20 parts by weight, the strength will be low due to the transition of the alumina cement hydrate after curing at high temperature and high pressure in an autoclave, and if it is less than 5 parts by weight, the effect of adjusting the curing time will be poor, which is not preferable.

Further, the aqueous foam is a mixture of a foaming agent and water, and examples of the foaming agent include higher alcohol type, synthetic polymer metal salt type and keratin degrading protein type.

The mixing ratio of the foaming agent and water is preferably 98 to 70 parts by weight of water with respect to 2 to 30 parts by weight of the foaming agent, and makes independent aqueous bubbles by the foaming agent and air to a bulk specific gravity of about 0.02 to 0.1 g / cm ³ . It is preferable to foam. It is also possible to add, for example, polyvinyl alcohol or methyl cellulose as a bubble stabilizer in an amount of at most 5 parts by weight with respect to the aqueous bubbles.

The CaO-containing mineral powder may be added to AC in advance, may be directly added to the rapid hardening slurry, or may be added as a slurry mixed with water.

As a method for mixing the slurry, a fluid mixing mixer is preferably used, and either a batch type or a continuous type may be used.

The method of pouring the slurry is preferably a method of pouring it into a mold set beforehand, in terms of handling and filling properties,
A method of collecting the slurry with a mold may be used.

The high temperature and high pressure curing condition is preferably within the condition range of (170 to 200 ° C -10 to 20 kg / cm ² ) in the steam pressurization method using an autoclave, but the method is not particularly limited as long as vamorite is produced by hydrothermal synthesis. .

〔Example〕

 Next, the present invention will be described with reference to Examples and Comparative Examples.

Example 1 A hydraulic slurry comprising the cement composition shown in Table 1, a rapid hardening slurry shown in Table 2 and a bulk specific gravity of 0.05 g / cm ³ foamed with 7 parts by weight of a proteolytic foaming agent and 93 parts by weight of water.
The rapid-curing foamed slurry mixed with the water-based air bubbles was poured into a mold, and after curing, the mold was removed, and further cured at high temperature and high pressure in an autoclave to produce aerated concrete, and its physical properties were measured. The results are shown in Table-3.

The hydraulic CA shown in Table-1 is a blend of Chinese bauxite and Denki Kagaku Co., Ltd. quicklime. After melting in an electric furnace, the clinker cooled with high pressure air has a Blaine value of 5,000 cm ² / g in a batch type ball mill. It was crushed like
The mineral composition was confirmed by a powder X-ray diffraction method using Cu-Kα radiation.

The non-hydraulic minerals shown in Table 2 are bauxite produced in China as an alumina source, quick lime manufactured by Denki Kagaku Kogyo as a calcia source, fused silica manufactured by Denki Kagaku Kogyo as a silica source, and magnesia manufactured by Ube Chemical Co., Ltd. as a magnesia source. A clinker was produced by combining and combining clinker, Australian rutile sand as a titania source, and iron for pigments made from Ishihara Sangyo Co., Ltd. as an iron source with a target mineral.

For the production of clinker, only C ₄ AF was fired in a silicon knit electric furnace, and the others were melted in an electric furnace.

Crushing of clinker and confirmation of mineral composition were performed in the same manner as hydraulic CA.

The physical properties were measured by the following methods.

Casting time: After mixing the rapid hardening slurry, flow cup (φ60, H
The time required for the F-flow value of 90 mm) to reach 140 mm was set.

Initial curing time: The time required for the temperature of the rapid-curing foamed slurry to rise by 10 ° C. immediately after casting was measured with a temperature recorder.

Initial strength: The strength after a lapse of a predetermined time after placing the rapid hardening foamed slurry in the mold was measured as a penetration resistance value.

<Materials used> Portland cement: Ordinary Portland cement AC: JIS R-2511 Class 1 commercial alumina cement Silica powder: Silica stone powder with a Blaine value of about 3,000 cm ² / g Admixture: Slaked lime Foaming agent: Keratin-based proteolytic foaming agent Delaying Agent R1: Sodium citrate R2: Citric acid R3: Sodium carbonate As shown in Table 3, when the manufacturing method of the present invention is used, the casting time and the initial curing time of the rapid-curing foamed slurry can be arbitrarily adjusted, and the delicate consistency such as the design processing on the panel surface can also be adjusted. .

Therefore, it is possible to set a curing time suitable for each manufacturing process, and the productivity of cellular concrete is improved.

Example 2 The procedure of Example 1 was repeated except that the rapid hardening slurry shown in Table 4 was used.

The results are shown in Table-5.

The physical properties were measured by the following methods.

Medium-term strength: The cast specimen (10φ x 20 cm) was cured at room temperature for 20 hours, put in an autoclave, and cured at 180 ° C, 10 kg / cm ² for 8 hours at high temperature and high pressure, and then allowed to cool to room temperature as the compression strength. .

The measurement of other physical properties and the materials used were in accordance with Example 1.

As shown in Table 5, when the production method of the present invention is used, the casting time and the initial curing time of the rapid-curing foamed slurry can be arbitrarily adjusted without significantly lowering the medium-term strength after high-temperature and high-pressure curing by an autoclave. You can also adjust the subtle consistency such as designing the surface.

For this reason, it is possible to set a curing time suitable for each manufacturing process, the occurrence of cracks and the like after curing at high temperature and high pressure is small, and the yield of good products is improved.

Example 3 The procedure of Example 2 was repeated except that the rapid hardening slurry shown in Table 6 was used.

The results are shown in Table-7.

As shown in Table 7, when the production method of the present invention is used, the casting time and the curing time of the rapid hardening foamed slurry can be adjusted arbitrarily.

Further, sufficient strength can be obtained even after curing in the autoclave.

〔The invention's effect〕

By using the production method of the present invention, the curing time of the rapid-curing foamed slurry can be arbitrarily adjusted, the adverse effects such as strength reduction are small, and the initial curing time suitable for each production process can be obtained, so that the panel surface is patterned. It is easy to adjust even the delicate consistency.

Therefore, capping, designing, etc. can be efficiently performed at the time of initial curing, and the productivity of the product is improved.

Further, the curing time of the slurry can be adjusted by using a small amount as compared with the conventional alumina cement.

Claims (1)

[Claims] 1. A rapid-curing foamed slurry is prepared by mixing a hydraulic slurry containing cement mixture and water, a rapid-curing slurry containing alumina cement and water, and water-based bubbles, casting, and molding at high temperature and high pressure after molding. In the method for producing aerated concrete obtained by the above, a method for producing aerated concrete, wherein CaO-containing mineral powder is added to the rapid-hardening slurry as a regulator of the initial setting time of the rapid-hardening foam slurry.