JP2004217510A - Water resistant lightweight cellular concrete and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide lightweight cellular concrete having excellent water resistance and excellent paintability without impairing the lightweight and excellent heat insulating properties of the lightweight cellular concrete.
SOLUTION: The cut surface perpendicular to the surface of lightweight cellular concrete has a contact angle of water of less than 100 ° or more than 50 °, and the permeability of the lightweight cellular concrete at the cut surface is 1000 cm ³ / m ² ···. It is a lightweight bubble concrete that is not more than day.
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Description

  The present invention relates to lightweight cellular concrete having water resistance and a method for producing the same.

BACKGROUND ART Lightweight cellular concrete, which is one of porous inorganic building materials, is widely used as an outer wall material, a floor material, a partition material, and a roof material of a building or a house because of its light weight and excellent heat insulation. However, on the other hand, there is a problem that water is easily absorbed. That is, about 80% of the volume of lightweight cellular concrete having a specific gravity of 0.45 to 0.55 is a void, and when water permeates into this void, various problems may be caused.
The most common method of preventing light absorption of lightweight cellular concrete used in an environment where water permeates is coating the surface of lightweight cellular concrete. However, the surface of lightweight cellular concrete has large irregularities on the surface formed during manufacturing and irregularities due to bubbles, and in order to ensure water resistance, it is necessary to apply a large amount of paint with excellent water resistance, which is troublesome and costly It takes. On the other hand, when lightweight cellular concrete is used for the outer wall, painting is required for the purpose of surface makeup except for a part of a warehouse or a factory. Therefore, there has been a demand for lightweight aerated concrete which can secure water resistance by applying a small amount of a low-priced paint for surface makeup.

Hitherto, for the purpose of imparting water resistance to lightweight cellular concrete, there has been proposed a method in which vapor of a water repellent such as alkoxysilane is brought into contact with lightweight cellular concrete (see Patent Documents 1 and 2 below). ). With these proposed methods, it is difficult to impart water resistance to the inside of lightweight cellular concrete because the pressure difference is not large, and the water resistance inside is insufficient, while high water repellency is imparted to the lightweight cellular concrete surface. However, the contact angle of water on the surface has a high value, and even when a water-based paint that is widely used for exterior wall coating is applied, the paint is repelled and uneven coating occurs, which makes it difficult to apply a decorative coating. There is a problem that it may be.
Also, the lightweight cellular concrete described in Patent Document 3 given below has high water repellency from the surface to the inside and is sufficiently satisfactory in water resistance, but has high water repellency on the surface of the lightweight cellular concrete and water-based paint. It may be difficult to apply a decorative paint.

Patent Documents 4 and 5 below propose a method of adding polydimethylsiloxane to a raw material slurry for producing lightweight cellular concrete to improve the water resistance of the lightweight cellular concrete itself. However, the lightweight cellular concrete obtained by this method can solve the problem of easy water absorption as shown in the comparative examples described later, but when the amount of polydimethylsiloxane added is small, the water repellency is not sufficiently exhibited. Although the contact angle of water is less than 100 °, the water permeability exceeds 1000 cm ³ / m ² · day. On the other hand, when the added amount is large, the water resistance is improved and the water permeability is 1000 cm ³ / day. Although it is not more than m ² · day, the water repellency is also improved at the same time, and the contact angle of water is 100 ° or more. In addition, when a large amount of polydimethylsiloxane is added, there is a problem in production such as difficulty in uniformly dispersing the polydimethylsiloxane.

JP-A-59-116465 JP-A-06-271371 International Publication No. 01/47834 JP-A-58-55359 Japanese Patent Publication No. 01-58148

  An object of the present invention is to provide a lightweight cellular concrete having excellent water resistance and excellent paintability without impairing the lightweight and excellent heat insulating properties of the lightweight cellular concrete, and a method for producing the same.

  The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, mixed lightweight cellular concrete in which water vapor was infiltrated into lightweight cellular concrete in an autoclave, from outside containing water vapor and a water repellent. It has been found that, when a gas is injected and treated, a lightweight cellular concrete excellent in coatability and water resistance can be obtained, and the present invention has been completed.

That is, the present invention
[1] The water contact angle of the cut surface perpendicular to the surface of the lightweight cellular concrete is less than 100 ° or more than 50 °, and the permeability of the lightweight cellular concrete at the cut surface is 1000 cm ³ / m ² · day. Water-resistant lightweight cellular concrete, characterized by the following:
[2] The water-resistant lightweight cellular concrete according to [1], wherein an equilibrium water permeability at a cut surface perpendicular to the surface of the lightweight cellular concrete is 450 cm ³ / m ² · day or less.
[3] In the differential pore size distribution obtained by the frozen mercury intrusion method immediately after the equilibrium permeability measurement, the pore size having the maximum peak is in the range of 0.01 to 0.1 μm [1] or Water-resistant lightweight cellular concrete according to [2],
[4] The amount of the water repellent extracted by water is 10% by weight or less of the amount of the water repellent contained in the lightweight cellular concrete, and the amount of the water repellent extracted by toluene and ethanol is contained in the lightweight cellular concrete. Water-resistant lightweight cellular concrete according to any one of [1] to [3], wherein the amount of the water-repellent agent is 10 wt% or less.
[5] The water-repellent agent is one or more selected from the group of alkylalkoxysilanes represented by the following general formula (1), wherein the water-repellent agent is one or more kinds. Water resistant lightweight cellular concrete,
R1nSi (OR2) 4-n (1)
(Here, R1 and R2 each independently represent an alkyl group. N represents an integer of 1 to 3. When n is 2 or more, R1s may be the same or different, and n is In the case of 2 or less, R2 may be the same or different.)
[6] The lightweight cellular concrete is put in the autoclave, steam is introduced, the vapor is permeated into the lightweight cellular concrete, the pressure inside the autoclave is reduced, and a mixed gas containing water vapor and a water repellent is autoclaved from outside the autoclave. A method for producing water-resistant lightweight cellular concrete, characterized by treating the lightweight cellular concrete by injecting into the
[7] Putting semi-cured lightweight cellular concrete into an autoclave, steam curing, and subsequently injecting a mixed gas containing water vapor and a water repellent from outside the autoclave into the autoclave to treat the lightweight cellular concrete. A method for producing water-resistant lightweight cellular concrete,
It is.

  The lightweight cellular concrete of the present invention has an effect of imparting excellent paintability and water resistance without impairing the lightweight and excellent heat insulating properties of the lightweight cellular concrete.

The present invention will be specifically described below.
The lightweight cellular concrete in the present invention is not particularly limited as long as it is lightweight cellular concrete. As a typical production method, for example, a siliceous raw material such as silica stone, and a cement typically represented by Portland cement, gypsum, a calcareous raw material such as quicklime mixed with a foaming agent such as aluminum as a main component. The raw material slurry is poured into a mold, cured to a hardness suitable for cutting, removed from the mold to form a semi-cured mortar block, which is cut with a tensioned wire such as a piano wire And autoclaving. Here, reinforcing steel bars or wire mesh may be provided in the lightweight cellular concrete as necessary.

The thickness of the lightweight cellular concrete used in the present invention is preferably from 10 to 300 mm, more preferably from 20 to 200 mm, and particularly preferably from 30 to 150 mm.
The contact angle of water on the cut surface of the water-resistant lightweight cellular concrete of the present invention needs to be less than 100 ° and not less than 50 °, preferably not more than 95 ° and not less than 60 °. ° or less, and more preferably in the range of 70 ° or more. If the contact angle of the cut surface is less than 100 ° or more than 50 °, water resistance is imparted to the center of the lightweight cellular concrete, and the water-based paint is uniformly applied to the surface of the lightweight cellular concrete as it is. Is possible.

In the present invention, the contact angle at the cut surface perpendicular to the surface means that the cut surface perpendicular to the lightweight cellular concrete surface is taken from the vicinity of the concrete surface to the center in a room kept at a constant temperature and humidity of 20 ° C. and a relative humidity of 65%. This is a value measured by a contact angle meter (CA-DT type) manufactured by Kyowa Interface Science Co., Ltd. at 10 mm intervals in the thickness direction.
The water permeability in the present invention was calculated by the following equation defined in JIS-5400.
Water permeability = V × 106 / {3.14 × (D / 2) ² }
Here, V is the amount of water permeability (cm ³ ), D is the diameter (mm) of the funnel used for the water permeability test device, and the method of measuring the amount of water permeability (V) was a method according to JIS-5400. That is, using a funnel having a diameter of Dmm and a permeation test device in which a 5 cm ³ female pipette whose end was cut off was connected and fixed with a vinyl tube, the center of the diameter of the funnel of the permeation test device was centered on the center of the cut surface held horizontally. The funnel is fixed with a sealing material (product name: Silicon Cork, manufactured by Konishi Co., Ltd.) so that no gap is formed, water is poured up to a height of 250 mm, and left for 24 hours. And read the amount of water permeation (V). In addition, JIS-5400 is for evaluating the water resistance of the coating film of the paint, and the funnel diameter is 75 mm as a standard. In the present invention, when the thickness of the lightweight cellular concrete is 75 mm or less, a water permeability test instrument having a diameter of 75 mm is used. Can not be used, the measurement is performed using a water-permeability test instrument having a smaller diameter in accordance with the thickness of the lightweight cellular concrete, and the water permeability is calculated by the above-mentioned calculation formula.

In the present invention, the water permeability is a value calculated based on the water permeability 24 hours after the start of the test, and the equilibrium water permeability is a value obtained by measuring the water permeability 24 hours later and further increasing the water permeability to a height of 250 mm. , And the operation of measuring the water permeability 24 hours later was repeated for 7 to 20 days, and the value was calculated based on the water permeability which became substantially constant.
Water permeability of the water-resistant lightweight concrete of the present invention ^is required to be less 1000cm ^{3 /} m 2 · ^day, preferably not more than 800cm ^{3 /} m 2 · ^day, more is 600cm ^{3 /} m 2 · day or less preferable. When the water permeability is 1000 cm ³ / m ² · day or less, sufficient water resistance is imparted to the center of the lightweight cellular concrete. Moreover, the equilibrium water permeability in order to satisfy the long-term water ^resistance, preferably 450cm ^{3 /} m 2 · day or ^less, more preferably 350cm ^{3 /} m 2 · day or ^less, 250cm ^{3 /} m 2 · day or less and particularly preferable.

  In the present invention, the frozen mercury intrusion method is a method of measuring the water permeability similar to the above, in which the water permeability is substantially constant, that is, the measurement is repeated until reaching the equilibrium water permeability, and then the depth from the surface to which the funnel is fixed. A portion up to 10 mm in the direction is cut out and crushed. 1-2 g of a sieve according to JIS-Z8801 that passes through an aperture of 4 mm (wire diameter of 1.4 mm) and does not pass through an aperture of 2 mm (linear 0.9 mm). The sample was lightly immersed in liquid nitrogen, frozen, and then quickly filled into a sample tube and set in a pore size distribution measuring device (Pore Size 9320, manufactured by Micrometrics, USA). And a degree of vacuum of about 5 Pa. Here, the differential pore diameter distribution by the mercury intrusion method is obtained by first-order differentiation of an integral curve of the pore amount with respect to the measured pore diameter. In general, the mercury intrusion method can measure a pore diameter of about 6 nm to 360 μm, but the obtained pore diameter does not represent the actual diameter of the pore, but the size of the gap existing between the constituent materials. It is used as an index of the size and is an effective analysis tool when describing the pore structure of lightweight cellular concrete. The contact angle between mercury and lightweight cellular concrete was 130 °, the surface tension of mercury was 484 dyn / cm, and the measured pressure was converted to the pore diameter assuming that the pores were cylindrical. It is important for the measurement of the differential pore distribution diameter by the frozen mercury intrusion method that the permeated water in the lightweight cellular concrete is not dried by equilibrium water permeability measurement. In addition, the sample tube may be cooled with dry ice or the like during measurement to prevent the temperature in the lightweight cellular concrete from rising and freezing water from melting, but the solidification temperature of mercury- When cooled below 38.8 ° C., no mercury is injected.

  Here, in the lightweight cellular concrete in which the permeability measurement was repeated until the water permeability reached the equilibrium, the pores in which the water-resistant layer was formed by the water-repellent did not permeate water, and remained in the voids. Water penetrates into the pores where no layer is formed, and the pores are filled with water.When immersed in liquid nitrogen in this state, water solidifies in the pores filled with water, and the fine pores are formed. The hole will be closed. In other words, when the water filled in the pores solidifies, the pores apparently disappear, and even when the mercury intrusion method is measured in this state, the pores in which the water solidifies, that is, the water repellent, A pore in which a water-resistant layer is not formed by the agent cannot be measured. By this method, it is possible to specify the pores in which a water-resistant layer is formed by a water-repellent agent, though roughly, and in order to satisfy the water-resistance performance of the lightweight cellular concrete of the present invention, the differential pressure obtained by the frozen mercury intrusion method is used. In the pore diameter distribution curve, it is important that the pore diameter having the maximum peak is 0.01 to 0.1 μm, preferably 0.03 to 0.08 μm, and more preferably 0.04 to 0.07 μm.

In the present invention, in order to further satisfy long-term water resistance, it is important that the water repellent contained in the lightweight cellular concrete does not leak from the lightweight cellular concrete. Then, each extraction rate of the water repellent contained in the lightweight cellular concrete with water, ethanol and toluene was measured by the following method.
The respective extraction rates of the water repellent with water, ethanol, and toluene were measured by a gas chromatograph (HP6890, manufactured by HEWLETT PACKARD) equipped with a thermal decomposition device (PY2010D, manufactured by Frontier Laboratories) (hereinafter, referred to as pyrolyzed gas chromatograph). Measured and determined. First, the lightweight cellular concrete containing the water repellent before extraction is dried in a hot air dryer at 60 ° C. (Thai Espec Co., Ltd., PHH401) for 24 hours, ground in a mortar and placed in a desiccator containing a desiccant (silica gel). , And left for 24 hours under reduced pressure with a vacuum pump (Vacuum Kiko Co., Ltd. DAH-60), take 5 mg, measure by the above pyrolysis gas chromatograph, and hold 10 minutes from the obtained chromatogram. The total peak area (Wo) was determined. Here, the peak within the retention time of 10 minutes in the chromatogram corresponds to saturated hydrocarbons and unsaturated hydrocarbons having about 1 to 3 carbon atoms generated by thermal decomposition of the water repellent.

On the other hand, in the case of measuring the extraction ratio with water, 1 g of lightweight cellular concrete containing a water repellent before extraction, which had been dried in advance with a hot air dryer at 60 ° C. for 24 hours, was ground in a mortar, and then mixed with 100 g of water (distilled water). The mixture was stirred for 1 hour to extract the water repellent contained in the lightweight cellular concrete, then filtered to obtain a solid content, air-dried, and then dried with a hot air drier at 60 ° C. for 24 hours. (Silica gel) was placed in a desiccator and left for 24 hours under reduced pressure with a vacuum pump. Next, after extraction and drying, 5 mg of lightweight cellular concrete was measured by pyrolysis gas chromatography in the same manner as described above, and the total peak area (W1) within a retention time of 10 minutes or less was obtained from the obtained chromatogram. . The extraction rate [%] of the water repellent with water was calculated by the following equation.
Extraction rate = {1− (W1 / W0)} × 100
Similarly, in the case of measuring the extraction ratio with ethanol or toluene, the extraction solvent is simply changed from water to ethanol or toluene, and otherwise, the measurement is performed in the same manner as the measurement of the extraction ratio with water.

Here, W1 is the total peak area after extraction, and W0 is the total peak area before extraction. The pyrolyzer was set at 800 ° C., the inlet temperature was set at 230 ° C., the detector temperature was set at 230 ° C., and the temperature of the column was set from 35 ° C. to 230 ° C. at a rate of 10 ° C./min. The detector used was a flame ionization detector, and the column used was SUPEL-9PLOT (supplied by SUPELCO). Here, the extraction means that not only a part of the water repellent is eluted (dissolved) in water, ethanol, and toluene, but also the water repellent contained in the lightweight cellular concrete, including the case where it is physically leaked, Saying that it is removed to the outside.
In the present invention, among the water repellents contained in the lightweight cellular concrete, the amount of the water repellent extracted by water is 10 wt% or less of the contained water repellent, and the water repellent extracted by ethanol and toluene is used. The amount of the water repellent is preferably 10% by weight or less of the contained water repellent, the amount of the water repellent extracted by water is 8% by weight or less of the contained water repellent, and extracted with ethanol and toluene. It is more preferable that the amount of the water repellent contained is 8 wt% or less of the contained water repellent, the amount of the water repellent extracted with water is 6 wt% or less of the contained water repellent, and ethanol and It is particularly preferable that the amount of the water repellent extracted by toluene is 6% by weight or less of the contained water repellent.

  The water-resistant lightweight cellular concrete of the present invention has a water-resistant layer on the inner surface of the pores. The water resistant layer may be formed of any water repellent, but is preferably a water resistant layer formed of an organosilicon compound. The functional group (X) of the organosilicon compound is hydrolyzed to form a silanol group, and further forms a siloxane bond by chemically bonding with a silanol group of calcium silicate hydrate or the like constituting the lightweight cellular concrete. It is presumed that a water-resistant layer is formed on the inner surface of the pores of the cellular concrete and the outer surface of the lightweight cellular concrete, thereby exhibiting excellent water resistance. In the water-resistant lightweight cellular concrete of the present invention, it is not necessary to have a water-resistant layer on the entire inner surface of the pores, and if the contact angle of cut surface, water permeability, and equilibrium water permeability are satisfied, the water-resistant layer is formed. There may be a pore inner surface that is not provided.

  In the present invention, the most commonly used organosilicon compound is an alkylalkoxysilane, which can be represented by the general formula R1nSi (OR2) 4-n. Here, R1 and R2 each independently represent an alkyl group, which may be the same or different. More preferably, R1 is an alkyl group having 3 to 18 carbon atoms, and R2 is the most general-purpose methyl group or ethyl group. n represents an integer of 1 to 3. When n is 2 or more, R1 may be the same or different, and when n is 2 or less, R2 may be the same or different. Further, two or more kinds of the alkylalkoxysilanes represented by the above general formula can be used as a mixture. Other less commonly used organosilicon compounds can also be used. That is, the other organosilicon compound can be represented by the general formula RnSiX4-n. Here, R represents an alkyl group, an aryl group, or an allyl group, X is a functional group that generates a silanol group by hydrolysis, and is an alkoxyl group, an acetoxy group, a ketoxime group, an amide group, an amino group, a vinyl ether group, Represents a halogen atom, and n represents an integer of 1 to 3. When n is 2 or more, R may be the same or different. Further, R may be one in which hydrogen contained in an alkyl group, an aryl group, or an allyl group is substituted with fluorine. When n is 2 or less, X may be the same or different.

  As the alkylalkoxysilane used in the present invention, the most general-purpose alkyltrialkoxysilane (n = 1) among the alkylalkoxysilanes represented by the above general formula is preferable. Representative examples of the alkylalkoxysilane used in the present invention include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, and heptyltrimethoxy. Silane, octyltrimethoxysilane, nonyltrimethoxysilane, decyltrimethoxysilane, undecyltrimethoxysilane, dodecyltrimethoxysilane, tridecyltrimethoxysilane, tetradecyltrimethoxysilane, pentadecyltrimethoxysilane, hexadecyltrimethoxy Silane, heptadecyltrimethoxysilane, octadecyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, Rutriethoxysilane, pentyltriethoxysilane, hexyltriethoxysilane, heptyltriethoxysilane, octyltriethoxysilane, nonyltriethoxysilane, decyltriethoxysilane, undecyltriethoxysilane, dodecyltriethoxysilane, tridecyltriethoxysilane , Tetradecyltriethoxysilane, pentadecyltriethoxysilane, hexadecyltriethoxysilane, heptadecyltriethoxysilane, octadecyltriethoxysilane and the like.

  Among these representative examples, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, methyltriethoxysilane Silane, ethyltriethoxysilane, propyltriethoxysilane, butyltriethoxysila, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, octadecyltriethoxysilane are preferred, and propyltrimethoxysilane, butyltrimethoxysilane, hexyl Trimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, propyltriethoxysilane, Tilt Li ethoxy Sila, hexyl triethoxysilane, octyl triethoxysilane run, decyl triethoxysilane, octadecyl triethoxysilane are more preferable.

Hereinafter, the method for producing the water-resistant lightweight cellular concrete of the present invention will be described.
As a method of producing the water-resistant lightweight cellular concrete of the present invention, for example, after putting cured lightweight cellular concrete into an autoclave, introducing steam, allowing the steam to permeate the interior of the lightweight cellular concrete, and then reducing the pressure in the autoclave Then, a method of treating the lightweight cellular concrete by injecting a mixed gas containing water vapor and a water repellent from the outside of the autoclave into the autoclave, and putting the semi-cured lightweight cellular concrete into the autoclave and steam curing, Subsequently, there is a method of treating a lightweight cellular concrete by injecting a mixed gas containing water vapor and a water repellent from outside the autoclave into the autoclave.

  As a method of using the cured lightweight cellular concrete, the lightweight cellular concrete installed in the autoclave is heated at a temperature of 100 ° C. or higher, 230 ° C. or lower, and a gauge pressure of 0.1 MPa or higher and 2.32 MPa or lower under saturated steam, preferably. Under a saturated steam having a temperature of 120 ° C. or more and 210 ° C. or less and a gauge pressure of 0.2 MPa or more and 1.91 MPa or less, more preferably a temperature of 130 ° C. or more and 190 ° C. or less, and a gauge pressure of 0.27 MPa or more and 1.26 MPa. Under the following saturated steam, the steam is sufficiently permeated into the lightweight cellular concrete, and the inside of the autoclave is reduced to a gauge pressure of 0.3 MPa or less, preferably to a gauge pressure of 0.2 MPa or less, particularly preferably to a gauge pressure of 0 MPa or less. The pressure is reduced, and a mixed gas containing water vapor and a water repellent is added to the autoclave from outside the autoclave. It was injected into the blanking, and a method of processing a lightweight cellular concrete.

Here, when the lightweight cellular concrete placed in the autoclave is placed under steam and water vapor penetrates into the lightweight cellular concrete, the pressure inside the autoclave may be reduced beforehand, and then the lightweight cellular concrete may be placed under steam. Absent. In addition, after introducing steam into the autoclave and infiltrating the steam into the lightweight cellular concrete, the pressure in the autoclave is reduced again because the mixed gas containing the steam and the water repellent penetrates into the lightweight cellular concrete. This is to make it easier.
The method for steam curing the semi-cured lightweight cellular concrete is not particularly limited, but may be a known method. Here, since the high-temperature and high-pressure steam-cured lightweight cellular concrete is in a state in which the vapor has already penetrated into the lightweight cellular concrete, the mixed gas containing the vapor and the water repellent is not placed beforehand under the vapor. Can be injected into the autoclave.

  In the present invention, in the method of using cured lightweight cellular concrete and placing it under steam and then treating it with a mixed gas containing water vapor and a water repellent, post-processing such as patterning the lightweight cellular concrete surface Lightweight aerated concrete can be used. In general, lightweight cellular concrete is jointed after steam curing, but post-processing such as patterning on the lightweight cellular concrete surface may also be performed. This is a preferable mode. Also, in the method of curing a semi-hardened lightweight cellular concrete with steam and then treating it with a mixed gas containing steam and a water repellent, it is possible to treat the mixed gas without prior steam treatment, thereby improving production efficiency. This is a preferred mode of connection.

In the present invention, the pressure in the autoclave at the time of injecting and treating the mixed gas containing the water vapor and the water repellent into the autoclave depends on the thickness of the lightweight cellular concrete, but is higher than the pressure before injecting the mixed gas. Preferably, the pressure is increased by 0.01 MPa or more, more preferably by 0.1 MPa or more, particularly preferably by 0.3 MPa or more. By injecting a mixed gas of water vapor and a water repellent into the autoclave and pressurizing the autoclave, the difference between the pre-pressurized pressure and the post-pressurized pressure in the autoclave is used as a driving force, and the mixed gas is a lightweight foam concrete. It can quickly reach the internal void.
The method of injecting the mixed gas containing water vapor and the water repellent into the autoclave is not particularly limited. For example, high-temperature water vapor, preferably in a container containing at least one water repellent, is preferably used. A method of injecting high-temperature saturated steam and vaporizing the water-repellent to form a mixed gas, or mist or pre-vaporizing at least one type of water-repellent from an inlet provided in the middle of a steam pipe to be injected into the autoclave. And a method of injecting the mixed gas into a mixed gas. Here, the mixed gas containing water vapor and the water repellent to be injected into the autoclave depends on the type of the water repellent, but has a temperature of 100 to 250 ° C. and a pressure of 0.1 to 4 MPa, preferably a temperature of 150 to 250 MPa. The temperature is preferably 230 ° C. and a pressure of 0.5 to 3 MPa, more preferably a temperature of 170 to 210 ° C. and a pressure of 0.8 to 2 MPa.

Here, the time for treating with the mixed gas containing water vapor and the water repellent is usually 0.1 to 5 hours, but if the reaction between the water repellent and the lightweight cellular concrete is not completely completed, the water vapor After being treated with a mixed gas containing a water-repellent and a water-repellent agent, without further removing the lightweight cellular concrete from the autoclave, heat it from the outside so as to keep it at 100 to 200 ° C. in this state. After leaving the autoclave for a few days to 2 months, after the removal from the autoclave, the treatment such as heating at a temperature of 60 to 180 ° C. for about 0.5 to 1 week as long as the lightweight cellular concrete is not thermally degraded. No problem.
Here, the method of heating the lightweight cellular concrete without taking it out of the autoclave is not particularly limited, but a method of heating the autoclave with a heater or steam, a method of injecting steam into the autoclave again, or the like can be used. When steam is injected again without removing the lightweight cellular concrete from the autoclave, the pressure in the autoclave at the time of injecting the steam may be at a pressure of about the pressure treated with a mixed gas containing a water repellent and steam. preferable. The heating method after being taken out of the autoclave is also not particularly limited, but general hot air heating, far-infrared heating, steam heating, or the like can be used.

In the mixed gas of the water vapor and the water repellent of the present invention, the content of the water repellent in the mixed gas is preferably 0.01 to 15 mol%, more preferably 0.1 to 10 mol%, and more preferably 0.3 to 10 mol%. 5 mol% is particularly preferred. Here, the water vapor is preferably at a saturated vapor pressure, and the water repellent is preferably less than the saturated vapor pressure from an economic viewpoint that it condenses and loses at places other than the lightweight cellular concrete.
The amount of the water-repellent contained in the water-resistant lightweight cellular concrete of the present invention is as follows: the lightweight cellular concrete before containing the water-repellent is cut into a length of 40 mm, a width of 40 mm and a length of 160 mm, and dried at 105 ° C. for 24 hours. The weight ratio with respect to the absolute dry weight determined in the above is preferably 0.05 to 10.0 wt%, more preferably 0.1 to 5.0 wt%, and particularly preferably 0.5 to 3.0 wt%. Here, when the structure of the water repellent is changed by a reaction such as hydrolysis, the weight replaced with the structure before the change is used.

  In the present invention, the amount of the water-repellent agent contained in the lightweight cellular concrete was determined by the measurement of a gas chromatograph equipped with a thermal decomposition device in the same manner as described above. First, in order to prepare a calibration curve for quantifying the water repellent, the lightweight cellular concrete is crushed with a mortar, and the water repellent is added to the lightweight cellular concrete powder by 0.1, 0.3, 0.5, 1 Each of the lightweight cellular concrete powders added at a ratio of 0.0, 2.0, and 3.0 wt% was placed in a separate closed container, and kept at 80 ° C. for one month to remove the water repellent and the lightweight cellular concrete. After the reaction was completed, each of the water-repellent agents was finely pulverized in a mortar and dried with a hot-air dryer at 60 ° C. for 24 hours so that the content of the water-repellent agent was not uneven in the lightweight cellular concrete. (Silica gel) was placed in a desiccator and left for 24 hours under reduced pressure by a vacuum pump. Next, 5 mg of lightweight cellular concrete to which each water repellent was added was separately measured by pyrolysis gas chromatography, and the total peak area within a retention time of 10 minutes or less was obtained from the obtained chromatogram, and the obtained peak area was obtained. The sum was plotted against the amount of the water-repellent agent added to obtain a calibration curve. Here, a linear relationship was obtained for the calibration curve. Next, the amount of the water repellent in the lightweight cellular concrete containing an unknown amount of the water repellent was measured by pyrolysis gas chromatography in the same manner as described above, and the peak area sum within a retention time of 10 minutes was obtained from the obtained chromatogram. The water repellent amount can be calculated from the above calibration curve. In the present invention, since a pyrolysis gas chromatograph is used, even if the water repellent is hydrolyzed, condensed or reacted with lightweight cellular concrete, it can be decomposed and measured.

  The water-resistant lightweight cellular concrete of the present invention is characterized by having excellent water resistance while having a low water contact angle of less than 100 ° and 50 ° or more. The reason is not clear, but the present inventors speculate as follows. The high-temperature and high-pressure steam is condensed in the internal void of the lightweight cellular concrete by contacting the lightweight cellular concrete with a low temperature, and the liquefied water vapor seals the void. In other words, the water-repellent vapor cannot enter the water-sealed void, and the water-repellent cannot adhere to the surface of the void. Here, the internal voids in the lightweight cellular concrete refer to all voids present in the lightweight cellular concrete, such as gel holes, capillary condensation holes, and bubbles introduced during foaming. In general, in the case of a porous material such as lightweight cellular concrete, the water repellent does not adhere as much as the small voids inside the lightweight cellular concrete because the porous material condenses from smaller voids. On the other hand, when water permeates into the lightweight cellular concrete, the water permeates into the interior through large voids that are more easily permeated. In other words, the water repellent does not adhere to the fine voids that do not contribute much to the penetration of water into the lightweight cellular concrete, but the water repellent adheres to the voids that greatly contribute to the penetration of water, and However, the water-repellent of the lightweight cellular concrete is not sufficiently exhibited because the water repellent does not adhere to the fine voids.

  The water-resistant lightweight cellular concrete of the present invention has remarkably improved water resistance performance, and it is not necessary to apply water to secure water resistance as in the past, so it can be used only by applying a cosmetic coating. It is. Thus, the water-resistant lightweight cellular concrete of the present invention can be used as an outer wall material, a floor material, a partition material or a roof material, as well as the conventional use.

Hereinafter, the present invention will be described more specifically with reference to examples.
The various measuring methods used in the present invention are as follows.

<Water contact angle>
The contact angle of water is in a room maintained at a constant temperature and humidity of 20 ° C. and a humidity of 65%, and on a cut surface perpendicular to the panel surface, from the vicinity of the surface to the center, at 10 mm intervals in the thickness direction It was measured with a contact angle meter (CA-DT type) manufactured by Interface Science Co., Ltd., and the average value of the measured values was used.

<Permeability>
The water permeability was determined from the water permeability measured 24 hours after the start of the measurement, and was calculated by the following equation defined by JIS-5400. Water permeability = V × 106 / {3.14 × (D / 2) ² }
Here, V is the amount of water permeability (cm ³ ), D is the diameter (mm) of the funnel used for the water permeability test device, and the method of measuring the amount of water permeability (V) was a method according to JIS-5400. That is, using a water permeability test device in which a funnel with a diameter of 75 mm and a 5 cm ³ female pipette whose tip was cut off was connected and fixed with a vinyl tube, the center of the cut surface perpendicular to the surface of the lightweight aerated concrete held horizontally was placed at the center. After fixing the funnel with a sealing material (trade name: Silicon Cork, manufactured by Konishi Co., Ltd.) so that no gap is formed so that the center of the diameter of the funnel of the test instrument is in the middle, water is added up to a height of 250 mm, and left for 24 hours. The water height was read from the scale of the female pipette to determine the water permeability (V).

<Equilibrium permeability>
Equilibrium permeability, using the same permeability test equipment as the above permeability measurement, after measuring the amount of water permeability after 24 hours, additionally inject water up to a height of 250 mm, and subsequently measure the amount of water permeability after 24 hours This operation was repeated for 7 to 20 days, and was determined from the above formula based on the substantially constant water permeability.

<Frozen mercury injection method>
In the frozen mercury intrusion method, first, in the measurement of the water permeability as described above, the measurement is repeated until the water permeability is almost constant, that is, until the water permeability reaches the equilibrium water permeability, and then from the surface to which the funnel is fixed to 5 mm in the depth direction. A portion is cut out and crushed, and a sieve conforming to JIS-Z8801 is used to collect about 1 to 2 g of a material passing through an aperture of 4 mm (wire diameter of 1.4 mm) and not passing through an aperture of 2 mm (linear 0.9 mm). The light-weight aerated concrete sampled in Example 1 was immersed in liquid nitrogen, frozen, and then quickly filled into a sample tube. The sample was set in a pore size distribution measuring device (Pore Size 9320, manufactured by Micrometrics, USA), and the degree of vacuum was about 5 Pa. Was measured under the following conditions. Here, the differential pore diameter distribution by the mercury intrusion method is obtained by first-order differentiation of an integral curve of the pore amount with respect to the measured pore diameter. The pressure measured with a contact angle of 130 ° between mercury and lightweight cellular concrete and a surface tension of mercury of 484 dyn / cm was converted to a pore diameter assuming that the pores were cylindrical. The measurement of the differential pore distribution diameter by the frozen mercury intrusion method requires that the water in the lightweight cellular concrete not be dried by the equilibrium permeability measurement, so the temperature in the lightweight cellular concrete increases during the measurement. During the measurement, the sample tube may be cooled with dry ice or the like so that the frozen water is not melted. However, when the sample tube is cooled below the solidification temperature of mercury of −38.8 ° C., mercury is not injected.

<Extraction rate>
The extraction rate of the water repellent contained in the lightweight cellular concrete with water, ethanol, or toluene was measured and measured using a gas chromatograph (HP6890, manufactured by HEWLETT PACKARD) equipped with a pyrolyzer (PY2010D, manufactured by Frontier Laboratories).
First, lightweight cellular concrete containing a water-repellent agent before extraction is cut into 40 mm in length, 40 mm in width and 10 mm in length, dried with a hot-air dryer at 60 ° C. (Thai-Espec Co., Ltd. PHH401) for 24 hours, and ground in a mortar. After that, it was placed in a desiccator containing a desiccant (silica gel) and left for 24 hours under reduced pressure by a vacuum pump (DAH-60, Vacuum Kiko Co., Ltd.). Next, 5 mg of the dried lightweight cellular concrete was taken and measured by the above-mentioned pyrolysis gas chromatograph, and the total peak area within a retention time of 10 minutes or less was obtained from the obtained chromatogram.

On the other hand, in the case of measuring the extraction ratio with water, 1 g of lightweight cellular concrete containing a water repellent, which had been dried in advance with a hot air dryer at 60 ° C. for 24 hours, was ground in a mortar, and 100 g of water (distilled water) was added. The mixture was stirred for a period of time to extract the water repellent contained in the lightweight cellular concrete, then filtered to obtain a solid content, air-dried, and then heated with a hot air drier at 60 ° C. (Tabayspec Co., Ltd. PHH401) for 24 hours. After drying, it was placed in a desiccator containing a desiccant (silica gel) and left for 24 hours under reduced pressure with a vacuum pump (DAH-60, Vacuum Kiko Co., Ltd.). Next, in the same manner as described above, 5 mg of the extracted and dried lightweight cellular concrete was measured by pyrolysis gas chromatography, and the total peak area within a retention time of 10 minutes or less was obtained from the obtained chromatogram. The extraction rate (%) of the water repellent with water was calculated by the following equation.
Extraction rate = {1− (W1 / W0)} × 100

  Here, W1 is the total peak area after extraction, and W0 is the total peak area before extraction. The pyrolyzer was set at 800 ° C., the inlet temperature was set at 230 ° C., the detector temperature was set at 230 ° C., and the temperature of the column was set from 35 ° C. to 230 ° C. at a rate of 10 ° C./min. The detector used was a flame ionization detector, and the column used was SUPEL-9PLOT (supplied by SUPELCO). Similarly, in the case of measuring the extraction ratio with ethanol or toluene, the extraction solvent is simply changed from water to ethanol or toluene, and otherwise, the measurement is performed in the same manner as the measurement of the extraction ratio with water.

<Organosilicon compound content>
The amount of the organosilicon compound contained in the lightweight cellular concrete was determined by measurement with a gas chromatograph equipped with a pyrolyzer in the same manner as described above. Calibration curves were previously prepared for each organosilicon compound by the method described above. Next, the amount of the organosilicon compound in the lightweight cellular concrete containing the unknown amount of the organosilicon compound was measured by pyrolysis gas chromatography in the same manner as described above, and the peak area sum within a retention time of 10 minutes was obtained from the obtained chromatogram. The amount was calculated from the above calibration curve and converted into the amount of the organosilicon compound.

<Production example of lightweight cellular concrete substrate>
The lightweight cellular concrete used as the substrate was produced by the following method. 53 parts by weight of silica stone, 2.5 parts by weight of dry gypsum, 7.5 parts by weight of quick lime, 37 parts by weight of ordinary Portland cement are put into a tank containing 68 parts by weight of water with respect to 100 parts by weight of these solids, After mixing for 2 minutes, 0.06 parts by weight of aluminum powder was mixed and stirred for 30 seconds. Next, after injecting the obtained mortar slurry into a mold, while preserving at 60 ° C. for 90 minutes and pre-curing in a state in which evaporation of water is suppressed, the obtained semi-cured lightweight cellular mortar block is piano-wired. Cut. The obtained semi-cured lightweight cellular concrete was placed in an autoclave, the air in the autoclave was removed under reduced pressure, saturated steam was injected, and the mixture was cured at 180 ° C. for 4 hours under high temperature and high pressure.

[Example 1]
After taking out the lightweight cellular concrete obtained by the above-mentioned production method from the autoclave and leaving it sufficiently at room temperature until the temperature decreases, 16 pieces of the lightweight cellular concrete having a length of 600 mm, a width of 400 mm and a thickness of 100 mm are again autoclaved (volume). 1.25 m ³ ), the pressure was reduced to a gauge pressure of −0.09 MPa by a water ring vacuum pump (Shinko Seiki Co., Ltd. SW-150), and then a saturated steam at a gauge pressure of 1.7 MPa and 208 ° C. was injected. Then, after the inside of the autoclave was pressurized to a gauge pressure of 1.2 MPa over 50 minutes, the state was maintained for 10 minutes, and the pressure was reduced to atmospheric pressure over 50 minutes. Immediately, saturated steam having a gauge pressure of 1.7 MPa and a temperature of 208 ° C. was injected into another pressure vessel (volume of 0.375 m ³ ) containing 3850 g of propyltriethoxysilane (KBE-3033 manufactured by Shin-Etsu Chemical Co., Ltd.). The pressure inside the pressure vessel was set to 190 ° C., the gauge pressure was set to 1.2 MPa, and a mixed gas of propyltriethoxysilane vapor and steam obtained in the pressure vessel was injected into the autoclave, and the inside of the autoclave was gauged for 60 minutes. After the pressure was increased from 0.0 MPa (atmospheric pressure) to 0.6 MPa, the system was naturally cooled to room temperature.

After the water-resistant lightweight cellular concrete obtained in the present example was sufficiently dried, three pieces were randomly selected from 16 pieces, and each lightweight cellular concrete was vertically cut at a position of half a width (200 mm in width). Then, a sample having a length of 600 mm, a width of 200 mm, and a thickness of 100 mm was obtained. The water repellency of the cut surface was measured by measuring the contact angle of water at an interval of 10 mm from the vicinity of the surface in the thickness direction at a position of 300 mm in length of the sample. As a result of the measurement, the average value of the contact angle of water from the vicinity of the surface to the center was 86.5 °. The permeability was measured by placing four permeation test instruments having a funnel diameter of 75 mm on the same sample as that for which the contact angle of water was measured, and obtaining an average value of a total of twelve. In this example, the water permeability was 453 cm ³ / m ² · day, and the equilibrium water permeability was 109 cm ³ / m ² · day. Further, the amount of propyltriethoxysilane extracted with respect to water for 1 hour with stirring time is 0.9 wt%, the amount of propyltriethoxysilane extracted with respect to toluene is 0.7 wt%, and the amount extracted with respect to ethanol is 0.7 wt%. The amount of propyltriethoxysilane extracted was 1.2% by weight. The maximum peak of the differential pore size distribution obtained by the frozen mercury intrusion method from the sample immediately after the equilibrium water permeability measurement was 0.05 μm.

  The average content of propyltriethoxysilane was determined by calculating the amount of propyltriethoxysilane contained in each of the three lightweight cellular concretes, which were randomly selected and cut in the vertical direction at half the horizontal position, and the average value was obtained. The amount of propyltriethoxysilane contained in each lightweight aerated concrete was determined by cutting the above three lightweight aerated concrete pieces, which were cut in the vertical direction at the horizontal half position, further by shifting the same by 5 mm in the horizontal direction, and 600 mm in length, 5 mm in width, A sample having a thickness of 100 mm was prepared. Then, each sample was separately coarsely pulverized by a high-speed stamp mill (AS-143 ANS-143PS), then pulverized in a mortar, and heated at 60 ° C. by a hot air dryer (Tabayspeck Co., Ltd.). PHH401), placed in a desiccator containing a desiccant (silica gel), left for 24 hours under reduced pressure with a vacuum pump (DAH-60, Vacuum Kiko Co., Ltd.), and then dried. 5 mg of the sample powder was measured with a pyrolysis gas chromatograph, and the propyltriene contained in each sample was determined from the above calibration curve. The amount of toxic silane was determined and the average of the three measurements was taken. The average content of the obtained propyltriethoxysilane was 1.66 wt%.

[Example 2]
Water-resistant lightweight cellular concrete was obtained in the same manner as in Example 1 except that the organosilicon compound used was changed to 1500 g of propyltriethoxysilane.
The water-resistant lightweight cellular concrete obtained in this example was measured for the water contact angle in the same manner as in Example 1. As a result, the average value of the water contact angle from the vicinity of the surface to the center was 74. 0.8 °, water permeability was 566 cm ³ / m ² · day, and equilibrium water permeability was 158 cm ³ / m ² · day. Further, the amount of propyltriethoxysilane extracted with respect to water for one hour of stirring time is 2.5 wt%, the amount of propyltriethoxysilane extracted with respect to toluene is 1.8 wt%, and the amount of ethanol extracted with respect to ethanol is 1.8 wt%. The amount of propyltriethoxysilane extracted was 2.0% by weight. The maximum peak of the differential pore size distribution obtained from the sample immediately after the equilibrium water permeability measurement by the frozen mercury intrusion method was 0.07 μm, and the average content of propyltriethoxysilane was 0.47 wt%.

[Example 3]
A water-resistant lightweight cellular concrete was obtained in the same manner as in Example 1 except that the organosilicon compounds used were 2974 g of propyltriethoxysilane and 156 g of hexyltriethoxysilane.
Water contact of the water-resistant lightweight cellular concrete obtained in this example was measured in the same manner as in Example 1. The average value of the contact angle of water from the vicinity of the surface to the center is 88.8 °, the water permeability is 521 cm ³ / m ² · day, and the equilibrium water permeability is 113 cm ³ / m ² · day. Was. The total amount of propyltriethoxysilane and hexyltriethoxysilane extracted with respect to water for one hour of stirring time was 2.2% by weight, and the amount of propyltriethoxysilane extracted with respect to toluene was 1.%. The amount of propyltriethoxysilane extracted with respect to 5 wt% and ethanol was 1.8 wt%. The maximum peak of the differential pore size distribution obtained from the sample immediately after the equilibrium water permeability measurement by the frozen mercury intrusion method was 0.06 μm, which was the sum of the content of propyltriethoxysilane and the content of hexyltriethoxysilane. Was 1.30 wt%.

[Example 4]
A water-resistant lightweight cellular concrete was obtained in the same manner as in Example 1 except that the organosilicon compounds used were 2974 g of propyltriethoxysilane and 156 g of octadecyltriethoxysilane.
The water-resistant lightweight cellular concrete obtained in this example was measured for water contact in the same manner as in Example 1, and as a result, the average value of the water contact angle from the vicinity of the surface to the center was 89. 8 °, the water permeability was 410 cm 3 / m 2 · day, and the equilibrium water permeability was 45 cm 3 / m 2 · day.

  Further, the total amount of propyltriethoxysilane and octadecyltriethoxysilane extracted with respect to water for 1 hour with stirring time is 1.2 wt%, and the amount of propyltriethoxysilane extracted with respect to toluene is 2. The amount of propyltriethoxysilane extracted with respect to 1 wt% and ethanol was 1.3 wt%. The maximum peak of the differential pore size distribution obtained by the frozen mercury intrusion method from the sample immediately after the equilibrium water permeability measurement was 0.04 μm, and the sum of the propyltriethoxysilane content and the octadecyltriethoxysilane content was: 1.35 wt%.

[Example 5]
16 pieces of semi-hardened lightweight cellular concrete having a length of 600 mm, a width of 400 mm, and a thickness of 100 mm obtained by the above-mentioned production method are put into an autoclave (volume: 1.25 m ³ ), and after curing with steam, the lightweight cellular concrete is removed from the autoclave. Without taking it out, saturated steam at a gauge pressure of 1.7 MPa and 208 ° C. was placed in another pressure vessel (volume 0.375 m ³ ) containing 3850 g of propyltriethoxysilane (KBE-3033 manufactured by Shin-Etsu Chemical Co., Ltd.). The pressure inside the pressure vessel was set to 190 ° C., the gauge pressure was set to 1.2 MPa, the mixed gas of propyltriethoxysilane vapor and steam obtained in the pressure vessel was poured into the autoclave, and the inside of the autoclave was heated for 60 minutes. After the gauge pressure is increased from 0.0 MPa (atmospheric pressure) to 0.6 MPa, the temperature becomes room temperature. In was a natural cooling.

As a result of measuring the water contact angle of the water-resistant lightweight cellular concrete obtained in this example in the same manner as in Example 1, the average value of the water contact angle from near the surface to the center was 87. 0.6 °, the water permeability was 476 cm ³ / m ² · day, and the equilibrium water permeability was 112 cm ³ / m ² · day. Further, the amount of propyltriethoxysilane extracted with respect to water for 1 hour with stirring time is 1.1 wt%, the amount of propyltriethoxysilane extracted with respect to toluene is 2.5 wt%, and The amount of propyltriethoxysilane extracted was 2.0% by weight. The maximum peak of the differential pore size distribution obtained from the sample immediately after the equilibrium water permeability measurement by the frozen mercury intrusion method was 0.05 μm, and the average content of propyltriethoxysilane was 1.54 wt%.

[Comparative Example 1]
After the lightweight cellular concrete obtained by the above production method is sufficiently dried in a room temperature environment, it is cut into a length of 100 mm, a width of 100 mm, and a thickness of 100 mm, placed in a closed container (volume of 0.01 m ³ ), and placed in the closed container. After heating the attached piping to 180 ° C., the pressure was reduced to 300 Pa, most of the water contained in the lightweight cellular concrete was removed, and then in another closed vessel connected by a pipe that could be opened and closed by a valve (volume) 100 g of propyltriethoxysilane was added to 0.01 m ³ ), and the pressure was reduced to 300 Pa, followed by heating to 180 ° C. to vaporize the propyltrialkoxysilane to obtain a vapor pressure of 66000 Pa. Then, the valve was opened, the vapor of the alkoxysilane was injected into a closed container containing lightweight cellular concrete for about 2 minutes, the pressure in the closed container was set at 33,000 Pa, and the container was left as it was for 1 hour.

The water-repellent lightweight cellular concrete obtained in the present comparative example was cut vertically at a horizontal half position into a 50 × 100 plane to obtain a sample having a length of 100 mm, a width of 50 mm and a thickness of 100 mm. The water repellency of the cut surface was measured by measuring the contact of water at a position of 50 mm in length in the thickness direction at intervals of 10 mm from near the surface in the thickness direction. As a result of measuring the contact angle of water, the average value of the contact angle of water from the vicinity of the surface to the center is 129.7 °, the permeability is 567 cm ³ / m ² · day, and the equilibrium permeability is It was 104 cm ³ / m ² · day. Further, the amount of propyltriethoxysilane extracted with respect to water for 1 hour with stirring time is 0.9 wt%, the amount of propyltriethoxysilane extracted with respect to toluene is 1.2 wt%, and the amount extracted with respect to ethanol is 1.2 wt%. The amount of propyltriethoxysilane to be obtained was 0.8% by weight. The maximum peak of the differential pore size distribution obtained from the sample immediately after the equilibrium water permeability measurement by the frozen mercury intrusion method was 0.03 μm, and the average content of propyltriethoxysilane was 2.05 wt%. .
When the moisture in the lightweight cellular concrete is removed as in this comparative example and the alkoxysilane vapor is treated alone, the obtained lightweight cellular concrete is confirmed to have excellent water resistance and at the same time greatly improved water repellency. Was.

[Comparative Example 2]
In this comparative example, the light-weight cellular concrete was prepared in the same manner as described above except that 0.5 parts by weight of dimethyl silicone oil (KF-96 Shin-Etsu Chemical Co., Ltd.) was added to 100 parts by weight of the solid content in the mortar slurry. Obtained. Here, the size of the lightweight cellular concrete was 600 mm in length, 400 mm in width, and 100 mm in thickness.
The lightweight cellular concrete obtained in this comparative example was measured for contact with water in the same manner as in Example 1. As a result, the average value of the contact angle of water from the vicinity of the surface to the center was 58.6 °. And the water permeability was 3781 cm ³ / m ² · day, and the equilibrium water permeability was 1159 cm ³ / m ² · day. The amount of dimethylsilicone oil extracted with respect to water for 1 hour with stirring time was 39.5 wt%, the amount of dimethylsilicone oil extracted with respect to toluene was 12.5 wt%, and with respect to ethanol. The amount of dimethyl silicone oil extracted was 18.3 wt%. The maximum peak of the differential pore size distribution obtained by the frozen mercury intrusion method from the sample immediately after the equilibrium water permeability measurement was 0.13 μm.
It was confirmed that the lightweight cellular concrete obtained by this comparative example could not secure sufficient water resistance.

[Comparative Example 3]
In this comparative example, the lightweight cellular concrete is the same as the above-mentioned production method except that 3 parts by weight of an alkyl-modified silicone oil (KF-4003 Shin-Etsu Chemical Co., Ltd.) is added to 100 parts by weight of the solid content in the mortar slurry. I got it. Here, the size of the lightweight cellular concrete was 600 mm in length, 400 mm in width, and 100 mm in thickness.
The lightweight cellular concrete obtained in this comparative example was measured for the contact angle of water in the same manner as in Example 1. As a result, the average value of the contact angle of water from the vicinity of the surface to the center was 125.1. °, water permeability was 602 cm ³ / m ² · day, and equilibrium water permeability was 294 cm ³ / m ² · day. Further, the amount of the alkyl-modified silicone oil extracted with respect to water for one hour of stirring time is 0.9 wt% of water, and the amount of the alkyl-modified silicone oil extracted with respect to toluene is 33.4 wt%. The amount of the alkyl-modified silicone oil extracted with respect to ethanol was 14.1 wt%. The maximum peak of the differential pore size distribution obtained from the sample immediately after the equilibrium permeability measurement by the frozen mercury intrusion method was 0.35 μm.
The lightweight cellular concrete obtained according to this comparative example has significantly improved not only water resistance but also water repellency.

[Comparative Example 4]
In this comparative example, the lightweight cellular concrete is the same as the above-described production method except that 2 parts by weight of an alkyl-modified silicone oil (KF-4003 Shin-Etsu Chemical Co., Ltd.) is added to 100 parts by weight of the solid content in the mortar slurry. I got it. Here, the size of the lightweight cellular concrete was 600 mm in length, 400 mm in width, and 100 mm in thickness.
The lightweight cellular concrete obtained in this comparative example was measured for the contact angle of water in the same manner as in Example 1. As a result, the average value of the contact angle of water from the vicinity of the surface to the center was 122.7. °, the water permeability was 792 cm ³ / m ² · day, and the equilibrium water permeability was 296 cm ³ / m ² · day.
The amount of the alkyl-modified silicone oil extracted with respect to water for one hour of stirring time was 1.3 wt%, and the amount of the alkyl-modified silicone oil extracted with respect to toluene was 29.4 wt%, which was extracted with ethanol. The amount of the alkyl-modified silicone oil extracted was 14.0 wt%. The maximum peak of the differential pore size distribution obtained from the sample immediately after the equilibrium water permeability measurement by the frozen mercury intrusion method was 0.51 μm.
The lightweight cellular concrete obtained according to this comparative example has significantly improved not only water resistance but also water repellency.

[Comparative Example 5]
In this comparative example, the lightweight cellular concrete is the same as the above-described production method except that 1 part by weight of an alkyl-modified silicone oil (KF-4003 Shin-Etsu Chemical Co., Ltd.) is added to 100 parts by weight of the solid content in the mortar slurry. I got it. Here, the size of the lightweight cellular concrete was 600 mm in length, 400 mm in width, and 100 mm in thickness.
The lightweight cellular concrete obtained in this comparative example was measured for the water contact angle in the same manner as in Example 1, and as a result, the average value of the water contact angle from near the surface to the center was 103 °, The water permeability was 1188 cm ³ / m ² · day, and the equilibrium water permeability was 466 cm ³ / m ² · day.
Further, the amount of the alkyl-modified silicone oil extracted with respect to water for one hour of stirring time is 8.5 wt%, the amount of the alkyl-modified silicone oil extracted with respect to toluene is 26.3 wt%, and the amount with respect to ethanol is The amount of the alkyl-modified silicone oil extracted was 13.1 wt%. The maximum peak of the differential pore size distribution obtained from the sample immediately after the equilibrium permeability measurement by the frozen mercury intrusion method was 0.83 μm.
It was confirmed that the lightweight cellular concrete obtained by this comparative example had poor water resistance despite improved water repellency.

[Comparative Example 6]
In this comparative example, the light-weight cellular concrete is manufactured by the above-described method except that 0.5 parts by weight of an alkyl-modified silicone oil (KF-4003 Shin-Etsu Chemical Co., Ltd.) is added to 100 parts by weight of the solid content in the mortar slurry. Was obtained in the same manner as described above. Here, the size of the lightweight cellular concrete was 600 mm in length, 400 mm in width, and 100 mm in thickness.
The lightweight cellular concrete obtained in this comparative example was measured for contact with water in the same manner as in Example 1. As a result, the average value of the contact angle of water from the vicinity of the surface to the center was 83.4 °. The water permeability was 1302 cm ³ / m ² · day, and the equilibrium water permeability was 475 cm ³ / m ² · day.
Further, the amount of the alkyl-modified silicone oil extracted with respect to water for one hour of stirring time is 32.4 wt%, the amount of the alkyl-modified silicone oil extracted with respect to toluene is 15.4 wt%, and the amount with respect to ethanol. The amount of the alkyl-modified silicone oil extracted was 11.5 wt%. The maximum peak of the differential pore size distribution obtained from the sample immediately after the equilibrium water permeability measurement by the frozen mercury intrusion method was 0.91 μm.
It was confirmed that the lightweight cellular concrete obtained by this comparative example had poor water resistance despite improved water repellency. It was also confirmed that the amount of extraction with respect to water was very large.

  The lightweight cellular concrete of the present invention is suitable in the field of building materials because it is a lightweight cellular concrete having excellent water resistance and excellent paintability without impairing the lightweight and excellent heat insulating properties of the lightweight cellular concrete. Available to

Claims (7)

The water contact angle of the cut surface perpendicular to the surface of the lightweight cellular concrete is in a range of less than 100 ° and 50 ° or more, and the water permeability of the lightweight cellular concrete is 1000 cm ³ / m ² · day or less. Water resistant lightweight cellular concrete characterized by the following. ^2. The water-resistant lightweight cellular concrete according to claim 1, wherein an equilibrium water permeability in a section perpendicular to the surface of the lightweight cellular concrete is 450 cm ³ / m ² · day or less. The pore diameter having a maximum peak in the differential pore diameter distribution obtained by the frozen mercury intrusion method immediately after the equilibrium water permeability measurement is in the range of 0.01 to 0.1 μm. 2. Water-resistant lightweight cellular concrete according to item 1. The amount of water repellent extracted by water is 10 wt% or less of the amount of water repellent contained in lightweight cellular concrete, and the amount of water repellent extracted with toluene and ethanol is contained in lightweight cellular concrete. The water-resistant lightweight cellular concrete according to any one of claims 1 to 3, wherein the amount is 10 wt% or less. The water-resistant lightweight cellular concrete according to any one of claims 1 to 4, wherein the water repellent is one or more selected from the group of alkylalkoxysilanes represented by the following general formula (1).
R1nSi (OR2) 4-n (1)
(Here, R1 and R2 each independently represent an alkyl group. N represents an integer of 1 to 3. When n is 2 or more, R1s may be the same or different, and n is In the case of 2 or less, R2 may be the same or different.) Put lightweight cellular concrete in the autoclave, introduce water vapor, infiltrate the vapor into the lightweight cellular concrete, reduce the pressure in the autoclave, and inject a mixed gas containing water vapor and water repellent from the outside of the autoclave into the autoclave A method for producing water-resistant lightweight cellular concrete, comprising: treating the lightweight cellular concrete. After putting the semi-hardened lightweight cellular concrete into the autoclave and steam curing, the mixed gas containing steam and water repellent is continuously injected into the autoclave from outside the autoclave to process the lightweight cellular concrete. Method of producing water-resistant lightweight cellular concrete.