JP2007153687A - Xonotlite based calcium silicate lightweight panel and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a xonotlite based calcium silicate lightweight panel whose inside is provided with a reinforcing material such as a reinforcing rod in which a heating dimensional change and thermal shrinkage are reduced for further improving its heat resistance, and to provide its production method. <P>SOLUTION: A calcareous raw material composed of portland cement and quicklime, a siliceous raw material and plaster are blended in such a manner that the molar ratio of CaO/SiO<SB>2</SB>is controlled to 0.8 to 1.1, and also, the atomic ratio of Al/(Al+Si) is controlled to ≤6%. The blend is mixed with water, so as to be slurry. Metal aluminum powder is added to the slurry, so as to obtain a molding material. The molding material is cast into a molding flask at which a reinforcing material is beforehand arranged, is subjected to foaming-hardening treatment, and is subjected to steam curing treatment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a zonotolite-based calcium silicate lightweight panel used as a building material having excellent heat resistance, heat insulation and workability, and a method for producing the same.

  Zonotolite-based calcium silicate compacts are particularly excellent in heat resistance compared to tobermorite-based calcium silicate compacts known as ALC, and are therefore mainly used for construction such as heat retaining materials, heat insulating materials, and fireproof coating materials for high temperatures. Used in materials.

  Conventionally, as a method for obtaining a zonotlite-based calcium silicate molded body requiring strength such as a wall material or a flooring material, as described in JP-A-63-144158, silica stone which is a siliceous raw material is used. In order to improve the strength of the molded body by adding slaked lime, which is a calcareous raw material, rod-shaped wollastonite, fibrous asbestos, ceramic fibers, etc. are added, and water is further added to form a slurry. The obtained slurry is poured into a mold and molded, and then the entire mold is hydrothermally reacted in an autoclave.

  This method described in JP-A-63-144158 is required because the slurry made of raw materials such as silica, slaked lime and wollastonite is hard to harden and must be put in the autoclave together with the formwork. Depending on the size of the molded body to be obtained, a mold having various dimensions is required. Therefore, since there is a problem in terms of cost, after obtaining a large molded body, it is necessary to cut it into desired dimensions one by one for use. In practice, there are different dimensions depending on various applications. There is also a disadvantage that it is not suitable for cases where it is required.

As means for solving such problems, as described in Japanese Patent No. 2757878, a main raw material is a calcareous raw material made of Portland cement and quick lime, a siliceous raw material such as silica and quartz sand, and gypsum. The molar ratio of CaO / SiO ₂ is 0.7 to 1.1, the atomic ratio of Al / (Al + Si) is 7% or less, and the amount of gypsum added is 2% to 30% by mass of the total raw material solids. After being pre-hydrated, an appropriate amount of metal aluminum powder is added, cast into a mold, foam-cured, and then steam-cured at a temperature of 190 ° C. to 240 ° C. for an appropriate time in an autoclave. As a result, a zonotlite-based calcium silicate molded product having a zonotrite content of 35% by mass or more was obtained.

  The zonotlite-based calcium silicate molded body obtained by this method described in Japanese Patent No. 2757878 is lightweight because it has bubbles inside, and the abundance ratio of zonotlite crystals is 35% by mass or more. Therefore, the heat resistance can be improved. Moreover, since the raw material slurry cast into the mold has high curability because Portland cement is used as a raw material, it is taken out from the mold before performing steam curing with an autoclave, and the piano There is also an advantage that it can be easily cut into a desired size and shape using a wire or the like.

However, the obtained zonotlite-based calcium silicate molded body is extremely tough as this kind so that the compression strength is 30 kg / cm ² or more while being extremely light, but it is used as a wall material or a flooring material. There is a possibility that the strength may be slightly insufficient, and further improvement in strength is desired. Therefore, Japanese Patent Laid-Open No. 4-164872 discloses a zonotlite-based calcium silicate lightweight panel in which reinforcing materials such as reinforcing bars and wire meshes are arranged.

  The xonotlite-based calcium silicate lightweight panel described in JP-A-4-164872 has the heat insulation, heat resistance, and strength possessed by the zonotlite-based calcium silicate molded body described in Japanese Patent No. 2757878, and Since the inside is reinforced with a reinforcing bar or the like, the heat resistance is superior to that of conventionally known ALC.

ALC has a calcium silicate mineral called tobermorite (5CaO.6SiO ₂ .5H ₂ O) as a main component, and tobermorite has five molecules of crystal water. Therefore, ALC causes heat shrinkage of about 2% by 700 ° C.

On the other hand, zonotolite (6CaO.6SiO ₂ .H ₂ O) has one molecule of crystal water and is less than tobermorite. Therefore, compared with tobermorite, zonotrite has a smaller dimensional change caused by crystal decomposition due to heat dehydration. That is, the reason why the zonotlite-based calcium silicate is excellent in heat resistance is due to the characteristics of the zonotrite crystals.

  Thus, the xonotlite-based calcium silicate lightweight panel obtained by the production method described in JP-A-4-164872 reflects the characteristics of zonotlite crystals and is excellent in dimensional stability during high-temperature heating. The heat resistance performance is superior to that of the conventional ALC. However, in recent years, the demand for heat resistance performance has further increased, and a zonotolite-based calcium silicate lightweight panel has been required to have higher heat resistance.

  In particular, a zonotlite-based calcium silicate lightweight panel in which a reinforcing material such as a reinforcing bar is disposed is required to reduce heat shrinkage because the reinforcing steel reinforcing bar is thermally expanded by heating.

JP 63-144158 A

Japanese Patent No. 2757878

Japanese Patent Laid-Open No. 1644872

  The object of the present invention is to further improve the heat resistance of the zonotlite-based calcium silicate lightweight panel in which reinforcing materials such as reinforcing bars are arranged, and to reduce the heating dimensional change and thermal shrinkage, and the zonotolite-based calcium silicate lightweight panel, It is in providing the manufacturing method.

  In one aspect of the xonotlite-based calcium silicate lightweight panel of the present invention, the zonotrite-based calcium silicate lightweight panel is composed of a zonotrite-based calcium silicate molded body and a reinforcing material disposed therein.

  Specifically, the reinforcing material is disposed inside, the zonotolite production rate is 50% by mass to 80% by mass, and the heating dimensional change from room temperature to 700 ° C. is in the range of 0.0% to + 1.0%. And the thermal shrinkage at 700 ° C. to 900 ° C. is 1.0% or less.

  Furthermore, it is desirable that the reinforcing material is a reinforcing bar or a wire mesh made of carbon steel.

In the manufacturing method of the xonotlite-based calcium silicate lightweight panel of the present invention, the molar ratio of CaO / SiO ₂ is 0.8 to 1.1 with a calcareous raw material composed of Portland cement and quick lime, a siliceous raw material, and gypsum. And, it is blended so that the atomic ratio of Al / (Al + Si) is 6% or less, and after mixing with water to form a slurry, a metal aluminum powder is added to the slurry to obtain a molded body material, The molded body material is cast into a mold in which a reinforcing material is previously arranged, subjected to foam curing treatment, and subjected to steam curing treatment.

  It is desirable to add gypsum as a raw material for the molded body material.

  Furthermore, it is desirable to use a reinforcing bar or a wire mesh made of carbon steel as the reinforcing material.

  According to the present invention, even if a reinforcing bar is arranged inside, the possibility of cracking due to a dimensional change due to heating becomes extremely small, and it can be applied to wall materials, floor materials and the like that require heat resistance.

  The xonotlite-based calcium silicate lightweight panel of the present invention is composed of a zonotrite-based calcium silicate molded body and a reinforcing material disposed therein.

  Furthermore, the heating dimensional change from room temperature to 700 ° C. was in the range of 0.0% to + 1.0%. Moreover, the thermal contraction rate in 700-900 degreeC was 1.0% or less. Note that the “+” sign of the heating dimension change indicates expansion.

  It is known that the behavior of pyrolysis of zonotlite itself is stable up to 700 ° C. without being decomposed and expands up to 700 ° C. by heating. At about 750 ° C. to 850 ° C., the crystal water of the zonotlite crystal is lost and the crystal itself contracts.

  In the case of industrially obtained zonotlite, since there is a range of crystallinity, it is generally crystallized in a slightly wider range than the temperature range of 750 ° C. to 850 ° C., ie, 700 ° C. to 900 ° C. Water dehydrates.

  The xonotlite-based calcium silicate lightweight panel of the present invention includes a reinforcing material inside the zonotrite-based calcium silicate molded body. As the reinforcing material, a reinforcing bar or a wire mesh made of carbon steel is used, and a mat shape in which the reinforcing bars are welded may be used. Generally, it is an iron wire used in ALC panels and the like, and SWM-B defined in JISG3532 is preferable. This is a mild steel wire specified in JIS G3505, and the carbon content is about 0.1%.

Since carbon steel has an average coefficient of thermal expansion of about 15 × 10 ⁻⁶ from room temperature to 700 ° C., the thermal expansion coefficient of the reinforcing material using carbon steel from room temperature to 700 ° C. is about 1%.

  When a zonotlite-based calcium silicate compact with a reinforcing material inside is heated, due to the heat insulation of the zonotlite-based calcium silicate compact itself, the temperature of the built-in reinforcement is near the surface of the zonotlite-based calcium silicate compact. The temperature is lower by about 10 ° C. to 50 ° C. than the temperature of. For this reason, when the zonotlite-based calcium silicate molded body incorporating the reinforcing material is subjected to heat treatment, the thermal expansion coefficient of the reinforcing bars is lower than the above-mentioned 1% in heating from room temperature to 700 ° C.

  Since the zonotlite-based calcium silicate molded product of the present invention has a heating dimensional change from room temperature to 700 ° C. in the range of 0.0% to + 1.0%, cracks may occur due to the difference from the thermal expansion coefficient of the reinforcing bars. Can be made extremely low.

  Further, in the heat treatment at 750 ° C. to 850 ° C., the zonotlite-based calcium silicate compact shrinks with the dehydration of crystal water of the zonotlite crystals. This shrinkage cannot be avoided as long as it is a zonotlite-based calcium silicate, but if the thermal shrinkage at 700 ° C. to 900 ° C. is 1.0% or less, the zonotrite-based calcium silicate molded body containing a reinforcing bar is cracked. Is extremely difficult to occur. In particular, if the temperature of the internal reinforcing bar is 700 ° C. or higher, it transforms from zonotlite to wollastonite without causing cracks.

  Although the details of the reason are unknown, it is considered that the built-in rebars soften at a high temperature of 700 ° C. or higher and follow the contraction when zonotolite transitions to wollastonite to some extent.

  The zonotlite-based calcium silicate molded body having a dimensional change in heating from room temperature to 700 ° C. in the range of 0.0% to + 1.0% and a heat shrinkage at 700 ° C. to 900 ° C. of 1.0% or less is The production rate needs to be 50% by mass to 80% by mass. When the zonotolite production rate is less than 50% by mass, the proportion of the amorphous material called tobermorite crystals and CSH in the material constituting the zonotlite-based calcium silicate compact becomes large, particularly heating from room temperature to 700 ° C. With time dehydration, the shrinkage increases significantly. If the zonotolite production rate exceeds 80% by mass, the zonotolite component is the main component, and it has been expected that the zonotolite component is preferred. Was greater than 1.0%, which proved undesirable.

In the manufacturing method of the xonotlite-based calcium silicate lightweight panel of the present invention, the molar ratio of CaO / SiO ₂ is 0.8 to 1.1 with a calcareous raw material composed of Portland cement and quick lime, a siliceous raw material, and gypsum. And, it is blended so that the atomic ratio of Al / (Al + Si) is 6% or less, and after mixing with water to form a slurry, a metal aluminum powder is added to the slurry to obtain a molded body material, The molded body material is cast into a mold in which a reinforcing material is previously arranged, subjected to foam curing treatment, and subjected to steam curing treatment.

  As raw materials, a calcareous raw material and a siliceous raw material are used as main components, and any ordinary ALC production raw material can be used as it is. Further, as disclosed in the above-mentioned Japanese Patent No. 2757878, it is possible to increase the strength of the zonotlite molded body by adding gypsum.

One of the blending conditions is such that the molar ratio of CaO / SiO ₂ is 0.8 to 1.1. If it is less than 0.8, an amorphous substance called tobermorite or CSH is produced as a calcium silicate component other than zonotlite, and the zonotrite production rate cannot be made 50 mass% or more, particularly from room temperature. The heat shrinkage rate accompanying heating up to 700 ° C. increases. Even if it exceeds 1.1, calcium silicate-based components other than zonotlite are produced, and the zonotrite production rate cannot be 50% by mass or more.

The other of the blending conditions is such that the atomic ratio of Al / (Al + Si) obtained from Al ₂ O ₃ and SiO ₂ contained in all raw materials is 6% or less. The zonotlite component becomes difficult to be generated when the atomic ratio of Al / (Al + Si) is increased, and tobermorite is easily generated instead. In addition, since Al atoms are mainly mixed from cement, it is achieved by adjusting the blending ratio of cement.

  When the raw material is mixed with water to form a slurry, as described in the above-mentioned Japanese Patent No. 2757878, the mixture of Portland cement and siliceous raw material, and the mixture of quicklime and gypsum are mixed with each other. More preferably, water is added to the slurry to perform hydration before slurrying and casting.

  As the metal aluminum powder used in the foam hardening treatment, those for general ALC are used. The amount of the metal aluminum powder may be appropriately adjusted in consideration of the bulk specific gravity required for the zonotlite-based calcium silicate compact, and is usually adjusted so that the bulk specific gravity is about 0.3 to 0.7. .

  The steam curing treatment is performed under saturated steam pressure using an autoclave. The temperature range of steam curing is preferably 190 ° C to 240 ° C, but even if the temperature range is lower than this temperature range, it is possible to increase the production rate of the zonotlite component by increasing the time of steam curing in the autoclave. It is. Further, if the temperature is high, the production rate of the zonotlite component increases even if the steam curing time is short, but if it exceeds 200 ° C., the pressure in the autoclave becomes too high, which causes a problem in terms of equipment cost. In view of the production rate of the zonotlite component and the equipment cost, steam curing at 195 ° C. for about 6 hours is most preferable.

  Since the heat treatment time varies depending on the thickness and size of the panel to be manufactured, it cannot be specified unconditionally, but the rate of temperature rise is as small as possible so as to reduce the temperature difference between the internal rebar and the molded product surface as much as possible. Is preferred.

Example 1
Table 1 shows the composition of the raw materials used.

  After mixing with the raw material composition shown in Table 2 and setting the total solid amount to 100 parts by mass and adding 70 parts by mass of water as a slurry and mixing for 4 minutes, the bulk specific gravity of the product becomes 0.50 After adjusting the amount of metal aluminum powder (approx. 0.06%) and stirring for 30 seconds, cast into a 7m long, 1.5m wide, 0.7m high mold with pre-arranged reinforcing bars. It was crowded.

  After foam hardening, cut with piano wire to 50mm thickness, 1800mm length and 600mm width, insert into autoclave, and cure for 6 hours under saturated steam pressure at 195 ° C, light weight of zonotlite calcium silicate I got a panel.

  The following measurements were performed on the obtained zonotlite-based calcium silicate lightweight panel.

(1) The molded body part from which the reinforcing bars were removed was collected, and the collected molded body part was sufficiently pulverized and then dried at 105 ° C. for 2 hours to obtain an absolutely dry state. Initial mass: Heat from room temperature to 1000 ° C. from a thermal mass decrease curve up to 1000 ° C. using a differential thermal mass spectrometer (TG-DTA) for a sample of M (mg) at a rate of temperature increase of 20 ° C./min. Mass loss: A (mg) and thermal mass loss from 750 ° C. to 850 ° C .: B (mg) were determined. The zonotlite production rate (%) can be calculated by the following formula (see Japanese Patent No. 2757878).

  Zonotolite production rate (%) = {B / (MA)} / {18 / (714-18)} × 100

(2) The collected molded part was molded into a 5 mm square and 15 mm long prismatic shape, and the dimensional change from room temperature to 700 ° C. and from 750 ° C. to 850 ° C. at a temperature rising rate of 20 ° C./min. The shrinkage rate was measured.

(3) A 300 mm square was cut together with the reinforcing bar from the portion where the reinforcing bar was placed inside, and this was heat-treated in an electric furnace. First, the temperature was raised from room temperature to 700 ° C., the occurrence of cracks was observed, and then heated to 900 ° C. As for the heating temperature rising rate, the temperature rising time up to 900 ° C. was 1 hour.

  As evaluation items, the presence or absence of cracks at 700 ° C. and the presence or absence of cracks at 900 ° C. were compared.

  The obtained measurement results are shown in Table 3.

(Examples 2 and 3, Comparative Examples 1 to 4)
A zonotolite-based calcium silicate panel was obtained in the same manner as in Example 1 except that mixing was performed using the raw material blends shown in Table 2.

  Moreover, the same evaluation as Example 1 was performed.

  The obtained measurement results are shown in Table 3.

In Comparative Example 1, since the CaO / SiO ₂ molar ratio was as low as 0.70, the zonotolite production rate was only 45%. As a result, the dimensional change from room temperature to 700 ° C. was as large as −1.4%. Thereby, cracks occurred when heated to 700 ° C. in an electric furnace.

  In Examples 1 to 3, the zonotolite production rates were 52%, 78%, and 70%, and both the dimensional change during heating and the thermal shrinkage rate at 750 ° C. to 850 ° C. were reduced. As a result, heating up to 900 ° C. Also, no cracks were observed.

In Comparative Example 2, the CaO / SiO ₂ molar ratio was as high as 1.19. As a result, the zonotolite production rate decreased to 41%, the dimensional change during heating increased, and cracks occurred.

  In Comparative Example 3, by reducing Al / (Si + Al) to 2.0%, the zonotolite production rate increased to 85%, but the thermal expansion up to 700 ° C. exceeded + 1.0%, from 750 ° C. to The thermal contraction rate at 850 ° C. also increased and cracks occurred.

  In Comparative Example 4, since Al / (Si + Al) was increased to 6.9%, the zonotolite production rate was reduced to 38%, and in particular, shrinkage up to 700 ° C. was increased and many cracks were generated.

Claims (5)

  A reinforcing material is arranged inside, the zonotrite production rate is 50% by mass to 80% by mass, the heating dimensional change from room temperature to 700 ° C. is in the range of 0.0% to + 1.0%, and A zonotlite-based calcium silicate lightweight panel having a heat shrinkage rate of 700% or less at 700 ° C to 900 ° C.   The zonotlite-based calcium silicate lightweight panel according to claim 1, wherein the reinforcing material is a reinforcing bar or a wire net made of carbon steel. A calcareous raw material composed of Portland cement and quicklime and a siliceous raw material have a CaO / SiO ₂ molar ratio of 0.8 to 1.1 and an Al / (Al + Si) atomic ratio of 6% or less. After mixing and mixing with water to form a slurry, metal aluminum powder is added to the slurry to obtain a molded body material, and the molded body material is cast into a formwork in which a reinforcing material is previously placed and foamed. A method for producing a zonotlite-based calcium silicate lightweight panel, characterized by performing a curing treatment and a steam curing treatment.   The method for producing a zonotlite-based calcium silicate lightweight panel according to claim 3, wherein gypsum is further added as a raw material of the molded body material.   The manufacturing method of the zonotolite type | system | group calcium silicate lightweight panel of Claim 3 or 4 using the reinforcing bar or metal-mesh which consists of carbon steel as said reinforcement material.