JP4481631B2 - Water-resistant lightweight cellular concrete and its production method - Google Patents

Description

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

Lightweight cellular concrete, which is one of porous inorganic building materials, is widely used as an exterior wall material, flooring material, partition material, and roofing material for buildings or houses because it is lightweight and has excellent heat insulation properties. However, on the other hand, there is a problem that it is easy to absorb water. That is, in lightweight cellular concrete having a specific gravity of 0.45 to 0.55, almost 80% of the volume is a void, and when water penetrates into this void, various problems may be caused.
The most common method of preventing water absorption of the lightweight cellular concrete used in an environment where water penetrates is the coating of the lightweight cellular concrete surface. However, the surface of lightweight aerated concrete has large irregularities on the surface formed during production and irregularities due to bubbles, and it is necessary to apply a large amount of water-resistant paint to ensure water resistance. It takes. On the other hand, when lightweight cellular concrete is used for the outer wall, painting is necessary for the purpose of surface decoration, except for some parts such as warehouses and factories. Therefore, there has been a demand for lightweight cellular concrete that can secure water resistance simply by applying a small amount of a coating material for surface decoration.

So far, for the purpose of imparting water resistance to lightweight cellular concrete, a method of contacting the lightweight cellular concrete with vapor of a water repellent such as alkoxysilane has been proposed (see Patent Document 1 and Patent Document 2 below). ). In these proposed methods, since the pressure difference is not large, it is difficult to give water resistance to the inside of the lightweight cellular concrete and the water resistance inside is insufficient, while the surface of the lightweight cellular concrete is given high water repellency. The contact angle of water on the surface has a high value, and even when a water-based paint widely used for exterior wall painting is applied, the paint is repelled and uneven painting occurs, making it difficult to apply cosmetic paint. Have the problem of becoming.
In addition, the lightweight cellular concrete described in the following Patent Document 3 is provided with high water repellency from the surface to the inside and sufficiently satisfies the water resistance, but the surface of the lightweight cellular concrete has high water repellency, and water-based paint. It may be difficult to paint with makeup.

Patent Document 4 and Patent Document 5 below propose a method for improving the water resistance of lightweight cellular concrete itself by adding polydimethylsiloxane to a raw slurry for producing lightweight cellular concrete. However, the lightweight cellular concrete obtained by this method can solve the problem of easy water absorption as shown in Comparative Examples described later. However, when the amount of polydimethylsiloxane added is small, water repellency is not so much developed. Although the water contact angle is less than 100 °, the water permeability exceeds 1000 cm ³ / m ² · day. On the other hand, when the addition amount is large, the water resistance is improved and the water permeability is 1000 cm ³ / day. Although it becomes m ² · day or less, water repellency is 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, production problems such as difficulty in uniform dispersion also occur.

JP 59-116465 A Japanese Patent Laid-Open No. 06-271371 International Publication No. 01/47834 JP 58-55359 A 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, and a method for producing the same, without impairing the lightweight and excellent heat insulation performance of the lightweight cellular concrete.

The present inventors, contains an extensive result of extensive investigations, the lightweight concrete impregnated with lightweight concrete inside the steam in the autoclave, steam and water repellent vapor from the outside in order to solve the above problems It has been found that when a mixed gas is injected and processed, a lightweight cellular concrete having excellent paintability 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 in the range of less than 100 ° and 50 ° or more, 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
[2] The water-resistant lightweight cellular concrete according to [1], wherein the equilibrium water permeability in 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 water permeability measurement, the pore size having the maximum peak is in the range of 0.01 to 0.1 μm [1] or The water-resistant lightweight cellular concrete according to [2],
[4] The amount of water repellent extracted with water is 10 wt% or less of the amount of water repellent contained in the lightweight cellular concrete, and the amount of water repellent extracted with toluene and ethanol is included in the lightweight cellular concrete. The water-resistant lightweight cellular concrete according to any one of [1] to [3], wherein the water-repellent amount 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): [1] to [4] Water resistant lightweight cellular concrete,
R1nSi (OR2) 4-n (1)
(Here, R1 and R2 each independently represents an alkyl group. N represents an integer of 1 to 3. When n is 2 or more, R1 may be the same or different, and n is In the case of 2 or less, each R2 may be the same or different.)
[6] Put lightweight cellular concrete in an autoclave, and introducing steam, impregnated with steam inside said light amount cellular concrete steps down the inside of the autoclave, a mixed gas containing steam and the water-repellent agent vapor from the outside of the autoclave A method for producing water-resistant lightweight aerated concrete, characterized by being injected into an autoclave and treating the lightweight aerated concrete,
[7] A semi-cured lightweight cellular concrete is placed in an autoclave , steam-cured at high temperature and pressure, and then the lightweight cellular concrete is continuously removed from the autoclave at a temperature of 100 to 250 ° C. and a pressure of 0.1 to 0.1. A method for producing water-resistant lightweight cellular concrete, characterized by injecting a mixed gas containing 4 MPa of water vapor and water repellent vapor into an autoclave to treat 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 performance of the lightweight cellular concrete that is excellent in light weight and heat insulation.

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 and a calcining raw material such as cement, gypsum and quick lime represented by ordinary Portland cement were mixed as a main component with a foaming agent such as aluminum. The raw material slurry is poured into a mold and cured to a hardness suitable for cutting, then removed from the mold to form a semi-cured mortar block, which is cut with a wire such as a piano wire that is tensioned Is a method of curing an autoclave. Here, the lightweight cellular concrete may be provided with reinforcing reinforcing bars or wire nets as necessary.

The thickness of the lightweight cellular concrete used in the present invention is preferably 10 to 300 mm, more preferably 20 to 200 mm, and particularly preferably 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 in the range of less than 100 ° and 50 ° or more, preferably in the range of 95 ° or less and 60 ° or more. More preferably, it is in the range of not more than ° and not less than 70 °. When the contact angle of the cut surface is less than 100 ° and in the range of 50 ° or more, water resistance is imparted to the center of the lightweight cellular concrete, and the water-based paint is uniformly applied to the lightweight cellular concrete surface 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 maintained from the vicinity of the concrete surface to the center in a room maintained at a constant temperature and humidity of 20 ° C. and a relative humidity of 65%. It is a value measured with a contact angle meter (CA-DT type) manufactured by Kyowa Interface Science Co., Ltd. at intervals of 10 mm in the thickness direction.
The water permeability in the present invention was calculated by the following formula defined by JIS-5400.
Water permeability = V × 106 / {3.14 × (D / 2) ² }
Here, V is the water permeability (cm ³ ), D is the caliber (mm) of the funnel used in the water permeability test instrument, and the method for measuring the water permeability (V) was a method based on JIS-5400. That is, using a water permeability test instrument in which a funnel having a diameter of Dmm and a 5 cm ³ measuring pipette with a tip cut off are connected and fixed by a vinyl tube, the center of the diameter of the funnel of the water permeability test instrument is centered on the horizontally held cutting surface. The funnel is fixed with a sealing material (product name: Silicon Coke, manufactured by Konishi Co., Ltd.) so that there is no gap between the funnel, water is added to a height of 250 mm, and left for 24 hours. Measure the water permeability (V). JIS-5400 evaluates the water resistance of the paint film, and the funnel diameter is 75 mm as a standard. In the present invention, when the lightweight cellular concrete thickness is 75 mm or less, the water permeability test equipment has a diameter of 75 mm. Since it cannot be used, it measures using the water-permeable test instrument which made the diameter small according to the thickness of the lightweight cellular concrete, and it calculates with the calculation formula which calculates | requires the said water permeability.

In the present invention, the water permeability is a value calculated on the basis of the water permeability 24 hours after the start of the test, and the equilibrium water permeability is a water level up to a height of 250 mm after measuring the water permeability 24 hours later. This is a value calculated on the basis of the substantially constant water permeability by repeating the operation of continuously injecting and measuring the water permeability after 24 hours for 7 to 20 days.
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 refers to the measurement of water permeability in the same manner as described above, and after repeating the measurement until the water permeability reaches substantially constant, that is, reaches the equilibrium water permeability, the depth from the surface to which the funnel is fixed is determined. A portion up to 10 mm in the direction is cut out and crushed, and in a sieve according to JIS-Z8801, 1 to 2 g that passes through an opening of 4 mm (wire diameter 1.4 mm) and does not pass through an opening of 2 mm (linear 0.9 mm). After the sampled light aerated concrete was immersed in liquid nitrogen and frozen, it was quickly filled in the sample tube and set in a pore size distribution measuring device (Pore Sizer 9320 manufactured by Micrometrics, USA). Measured under conditions of a degree of vacuum of about 5 Pa. Here, the differential pore size distribution by the mercury intrusion method is obtained by first-order differentiation of the integral curve of the pore amount with respect to the measured pore size. Generally, in the mercury intrusion method, it is possible to measure a pore diameter of about 6 nm to 360 μm. However, the obtained pore diameter does not represent the actual pore diameter, but is a size of a gap existing between constituent materials. It is used as an index of the thickness and is an effective analysis means when describing the pore structure of lightweight cellular concrete. The contact angle between mercury and lightweight aerated concrete was 130 °, the surface tension of mercury was 484 dyn / cm, and the measured pressure was converted to pore diameter assuming that the pore shape was cylindrical. When measuring the differential pore distribution diameter by the frozen mercury intrusion method, it is important not to dry the infiltrated water in the lightweight cellular concrete by measuring the equilibrium water permeability. In order to prevent the temperature inside the lightweight cellular concrete from rising during the measurement and melting the frozen water, the sample tube may be cooled with dry ice or the like during the measurement. When cooled below 38.8 ° C, mercury is not injected.

  Here, the lightweight cellular concrete in which the water permeability measurement is repeated until the equilibrium water permeability is reached does not penetrate water into the pores in which the water-resistant layer is formed by the water repellent and remains in the voids. Water penetrates into pores in which 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. The hole will be blocked. In other words, when the water filled in the pores solidifies, the pores seem to disappear, and even if the mercury intrusion method is measured in that state, the water is solidified, that is, water repellent. The pores in which the water-resistant layer is not formed by the agent cannot be measured. By this method, it is possible to specify the pores in which the water-resistant layer is formed by the water repellent, but in order to satisfy the water-resistant performance of the lightweight cellular concrete of the present invention, the differential obtained by the frozen mercury intrusion method is used. In the pore size distribution curve, it is important that the pore size 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 the 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 with water, ethanol, and toluene of the water repellent contained in the lightweight cellular concrete was measured by the following method.
The extraction ratio of each of the water repellents with water, ethanol, and toluene is determined by a gas chromatograph (HP6890 manufactured by HEWLETT PACKARD) (hereinafter referred to as a pyrolytic gas chromatograph) equipped with a thermal decomposition apparatus (PY2010D manufactured by Frontier Labs). Measured and determined. First, in a desiccator, a lightweight cellular concrete containing a water repellent before extraction was previously dried for 24 hours in a hot air dryer (Tabba Espec Co., Ltd. PHH401) at 60 ° C., pulverized in a mortar, and a desiccant (silica gel) added. 5 mg of what was left for 24 hours under reduced pressure with a vacuum pump (Daiki Kiko Co., Ltd. DAH-60), measured with the above pyrolysis gas chromatograph, and retention time 10 minutes from the resulting 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 produced by thermal decomposition of the water repellent.

On the other hand, in the case of measuring the extraction rate with water, 1 g of lightweight cellular concrete containing a water repellent before extraction previously dried for 24 hours with a hot air dryer at 60 ° C. is ground in a mortar and then mixed with 100 g of water (distilled water). And stirring for 1 hour to extract the water repellent contained in the lightweight cellular concrete, followed by filtration to obtain a solid content, air drying, and drying in a hot air dryer at 60 ° C. for 24 hours. It was placed in a desiccator containing (silica gel) and allowed to stand for 24 hours under reduced pressure with a vacuum pump. Next, after extraction and drying, 5 mg of lightweight cellular concrete was measured with a pyrolysis gas chromatograph in the same manner as described above, and the total peak area (W1) within a retention time of 10 minutes was determined 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 rate with ethanol or toluene, only the extraction solvent is changed from water to ethanol or toluene, and the rest is performed in the same manner as the measurement of the extraction rate with water.

Here, W1 is the total peak area after extraction, and W0 is the total peak area before extraction. The pyrolysis apparatus is set to 800 ° C., the inlet temperature is 230 ° C., the detector temperature is 230 ° C., the column is set to be heated from 35 ° C. to 230 ° C. at a heating rate of 10 ° C./min, the carrier gas is helium, A flame ionization detector was used as a detector, and SUPEL-9PLOT (manufactured by SUPELCO) was used as a column. Here, the extraction means that the water repellent contained in the lightweight cellular concrete includes not only a part of the water repellent eluting (dissolving) in water, ethanol, or toluene, but also physically leaking. Says that it is removed outside.
In the present invention, among the water repellents contained in the lightweight cellular concrete, the amount of water repellent extracted by water is 10 wt% or less of the water repellent contained, and the water repellent extracted by ethanol and toluene. The amount of the water repellent is preferably 10 wt% or less of the contained water repellent, the amount of the water repellent extracted by water is 8 wt% or less of the contained water repellent, and extracted with ethanol and toluene. More preferably, the amount of water repellent to be added is 8 wt% or less of the water repellent contained, 6 wt% or less of the water repellent containing the amount of water repellent extracted by water, and ethanol and It is particularly preferable that the amount of water repellent extracted with toluene is 6 wt% or less of the water repellent contained.

  The water-resistant lightweight cellular concrete of the present invention has a water-resistant layer on the pore inner surface. The water-resistant layer may be formed from any water repellent, but is preferably a water-resistant layer formed from an organosilicon compound. The functional group (X) of the organosilicon compound is hydrolyzed to become a silanol group, and further, it is chemically bonded to the silanol group of the calcium silicate hydrate constituting the lightweight cellular concrete to form a siloxane bond and light weight. 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 to develop 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 all the pore inner surfaces, and if the contact angle, water permeability, and equilibrium water permeability of the cut surface are satisfied, the water-resistant layer is formed. There may be a surface inside the pores that does not have.

  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 versatile 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 alkylalkoxysilanes represented by the above general formula can be used in combination. Also, although not very versatile, other organosilicon compounds can also be used. That is, other organosilicon compounds can be represented by the general formula RnSiX4-n. Here, R represents an alkyl group, an aryl group, an allyl group, X is a functional group that hydrolyzes to generate a silanol group, 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. R may be a group in which hydrogen contained in an alkyl group, aryl group, or allyl group is substituted with fluorine. When n is 2 or less, X may be the same or different.

  The alkylalkoxysilane used in the present invention is preferably the most versatile alkyltrialkoxysilane (n = 1) among the alkylalkoxysilanes represented by the above general formula. Representative examples of the alkylalkoxysilane used in the present invention include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, 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, methyltriethoxy Silane, ethyltriethoxysilane, propyltriethoxysilane, butyltriethoxysila, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, octadecyltriethoxysilane are preferred, propyltrimethoxysilane, butyltrimethoxysilane, hexyl Trimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, propyltriethoxysilane, Tilt Li ethoxy Sila, hexyl triethoxysilane, octyl triethoxysilane run, decyl triethoxysilane, octadecyl triethoxysilane are more preferable.

Below, the manufacturing method of the water-resistant lightweight cellular concrete of this invention is demonstrated.
As a method for producing the water-resistant lightweight aerated concrete of the present invention, for example, a cured lightweight aerated concrete is put into an autoclave, water vapor is introduced, water vapor is permeated into the lightweight aerated concrete, and then the pressure inside the autoclave is reduced. was placed a method of processing a light-weight cellular concrete mixed gas containing water vapor and the water-repellent agent vapor from the outside of the autoclave was poured into the autoclave, the semi-cured lightweight aerated concrete into the autoclave, after steam curing , a method of processing a light-weight cellular concrete continues injecting a mixed gas containing steam and the water-repellent agent vapor from the outside of the autoclave to autoclave.

As a method of using the cured lightweight cellular concrete, the lightweight cellular concrete installed in the autoclave is preferably subjected to saturated steam at a temperature of 100 ° C. or higher and 230 ° C. or lower, a gauge pressure of 0.1 MPa or higher and 2.32 MPa or lower. In a saturated water vapor at a temperature of 120 ° C. or higher and 210 ° C. or lower, a gauge pressure of 0.2 MPa or higher and 1.91 MPa or lower, more preferably a temperature of 130 ° C. or higher and 190 ° C. or lower, a gauge pressure of 0.27 MPa or higher, 1.26 MPa. It is placed under the saturated water vapor below, and water vapor is sufficiently permeated into the lightweight aerated concrete, and the inside of the autoclave is reduced to a gauge pressure of 0.3 MPa or less, preferably a gauge pressure of 0.2 MPa or less, particularly preferably a gauge pressure of 0 MPa or less. step down, auto gas mixture containing water vapor and the water-repellent agent vapor from the outside of the autoclave Injected into the slave, and a method of processing a lightweight cellular concrete.

Here, when the lightweight cellular concrete installed in the autoclave is placed under water vapor so that the moisture penetrates into the lightweight cellular concrete, the interior of the autoclave may be depressurized in advance, and then the lightweight cellular concrete may be placed under the steam. Absent. Further, by introducing steam into the autoclave, after the penetration of steam into lightweight in concrete, is to step down in the autoclave again, osmotic gas mixture containing water vapor and the water-repellent agent vapor to the inside of the lightweight concrete This is to make it easier.
Further, the method for steam curing the semi-cured lightweight cellular concrete is not particularly limited, but may be a known method. Here, lightweight cellular concrete is steam cured at high temperature and high pressure is already since a state in which water vapor is permeated to the inside said light amount aerated concrete, without putting in advance under steam containing water vapor and the water-repellent agent vapor mixture Gas can be injected into the autoclave.

In the present invention, after the cured lightweight aerated concrete is placed under steam, and treated with a mixed gas containing steam and water repellent steam , the surface of the lightweight aerated concrete is patterned. Processed lightweight cellular concrete can be used. Generally, lightweight aerated concrete is jointed after steam curing, but there are cases where post-processing such as patterning is applied to the lightweight aerated concrete surface. This is a preferable mode. In addition, the semi-cured lightweight aerated concrete is steam-cured and then treated with a mixed gas containing steam and water repellent steam. Is also preferable.

In the present invention, the pressure in the autoclave when processing a mixed gas containing steam and the water-repellent agent vapor is injected into the autoclave, varies depending on the thickness of the lightweight concrete, the pressure of before injecting the mixed gas It is preferable to make it higher by 0.01 MPa or more, more preferably by 0.1 MPa or more, and particularly preferably by 0.3 MPa or more. A mixed gas of water vapor and the water-repellent agent vapor is injected into the autoclave by pressurizing the autoclave, as the driving force difference before pressing pressure and post-compression pressure in the autoclave, the mixed gas is lightweight concrete Can be quickly reached.
A method of injecting a mixed gas containing steam and the water-repellent agent vapor in the autoclave is not required to be particularly limited, for example, high temperature steam in a vessel containing at least one water-repellent agent, preferably Injects high-temperature saturated water vapor to vaporize the water repellent to form a mixed gas, or mists or pre-vaporizes at least one water repellent from an inlet provided in the middle of the water vapor piping injected into the autoclave For example, a method of injecting with a vapor generated to form a mixed gas may be used. Here, a mixed gas containing steam and the water-repellent agent vapor to be injected in the autoclave varies depending on the type of water repellent agent, the temperature 100 to 250 ° C., a pressure 0.1～4MPa, preferably a temperature of 150 ˜230 ° C., pressure 0.5-3 MPa is preferable, temperature 170-210 ° C., pressure 0.8-2 MPa is more preferable.

Here, if the time for processing a mixed gas containing steam and the water-repellent agent vapor may typically 0.1 to 5 hours, the reaction between the water-repellent agent and lightweight concrete is not completely finished, after treatment with a gas mixture containing water vapor and water repellent vapor, further without removing the lightweight concrete from the autoclave, a heat treatment from the outside to retain the 100 to 200 ° C. in this state, after removal from the autoclave , Leave it at room temperature for several days to two months, remove it from the autoclave, and then heat it at 60 to 180 ° C for about 0.5 to 1 week. It doesn't matter.
Here, the method of heating the lightweight aerated 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 water vapor is injected again without removing lightweight cellular concrete from the autoclave, the pressure in the autoclave when water vapor is injected should be about the same as the pressure treated with the mixed gas containing water repellent vapor and water vapor. Is preferred. Also, the heating method after taking out from the autoclave is not particularly limited, but general hot air heating, far-infrared heating, steam heating or the like can be used.

In the mixed gas of steam and water repellent vapor present invention, the water repellent agent content of the mixed gas is preferably 0.01 to 15 mol%, more preferably 0.1 to 10 mol%, 0.3 ˜5 mol% is particularly preferred. Here, it is preferable that the water vapor has a saturated vapor pressure, and the water repellent is preferably less than the saturated vapor pressure from the economical viewpoint that it is condensed and lost in a place other than the lightweight cellular concrete.
In addition, the amount of water repellent contained in the water-resistant lightweight cellular concrete of the present invention was cut into 40 mm in length, 40 mm in width and 160 mm in length before the water repellent was added, and dried at 105 ° C. for 24 hours. The weight ratio to the absolute dry weight determined in this way 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 water repellent contained in the lightweight cellular concrete was determined by measurement of a gas chromatograph equipped with a thermal decomposition apparatus as described above. First, in order to prepare a calibration curve for quantifying the water repellent, the lightweight cellular concrete is pulverized with a mortar, and the water-repellent agent is 0.1, 0.3, 0.5, 1 Put each of the lightweight cellular concrete powders added in the ratios of 0.0, 2.0, and 3.0 wt% into separate sealed containers and hold at 80 ° C. for one month. After completely reacting, finely pulverized each in a mortar for 24 hours in a hot air dryer at 60 ° C. so that the content of the water repellent is not uniform in the lightweight cellular concrete, and then the desiccant It was placed in a desiccator containing (silica gel) and allowed to stand for 24 hours under reduced pressure with a vacuum pump. Next, 5 mg of lightweight cellular concrete to which each water repellent was added was separately measured with a pyrolysis gas chromatograph, and the total peak area within a retention time of 10 minutes was determined from the obtained chromatogram, and the resulting peak area was obtained. The total was plotted against the amount of water repellent added to provide a calibration curve. Here, a linear relationship was obtained for the calibration curve. Next, the amount of water repellent in lightweight cellular concrete containing an unknown amount of water repellent is measured by pyrolysis gas chromatograph in the same manner as described above, and the total peak area within 10 minutes of retention time is obtained from the obtained chromatogram. It can be calculated and converted to the amount of water repellent from the 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 despite a low water contact angle of less than 100 ° and 50 ° or more. The reason for this is not clear, but the present inventors speculate as follows. The high-temperature and high-pressure water vapor condenses in the internal voids of the lightweight cellular concrete by contacting the low-temperature lightweight cellular concrete, and the liquefied water vapor seals the interior of the voids. That is, the water repellent vapor cannot enter the sealed water gap, and the water repellent cannot adhere to the surface of the gap. Here, the internal voids of the lightweight cellular concrete refer to all voids existing inside 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 smaller void inside the lightweight cellular concrete because it condenses from a smaller void. On the other hand, when water penetrates into the lightweight cellular concrete, the water penetrates into the interior through a large gap that is more likely to penetrate. In other words, water repellent is not attached to fine voids that do not contribute much to the penetration of water into lightweight cellular concrete, but water repellent adheres to voids that greatly contribute to water penetration and water-resistant layers However, since the water repellent is not attached to the fine voids, the water-repellent property of the lightweight cellular concrete is not sufficiently exhibited.

  The water-resistant lightweight cellular concrete of the present invention has remarkably improved water resistance performance, and it is not necessary to ensure water resistance by painting as in the past, so it can be used simply by applying cosmetic makeup. 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 in more detail with reference to examples.
Various measurement methods used in the present invention are as follows.

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

<Water permeability>
The water permeability was determined from the water permeability measured 24 hours after the start of measurement, and was calculated by the following formula defined in JIS-5400. Water permeability = V × 106 / {3.14 × (D / 2) ² }
Here, V is the water permeability (cm ³ ), D is the caliber (mm) of the funnel used in the water permeability test instrument, and the method for measuring the water permeability (V) was a method based on JIS-5400. That is, using a water permeability test instrument in which a funnel with a diameter of 75 mm and a 5 cm ³ measuring pipette with a tip cut off are connected and fixed with a vinyl tube, the water permeability is centered on the cut surface perpendicular to the surface of the lightweight lightweight concrete held horizontally. After fixing the funnel with a sealing material (trade name Silicon Coke, manufactured by Konishi Co., Ltd.) so that there is no gap so that the center of the caliber of the funnel of the test instrument comes, put water to a height of 250 mm and leave it for 24 hours The underwater height was read from the scale of the female pipette, and the water permeability (V) was determined.

<Equilibrium water permeability>
Equilibrium water permeability is measured using the same water permeability test equipment as in the above-mentioned measurement of water permeability. After measuring the water permeability after 24 hours, water is additionally injected to a height of 250 mm, and then the water permeability after 24 hours is measured. This operation was repeated for 7 to 20 days, and was determined from the above calculation formula based on the substantially constant water permeability.

<Frozen mercury intrusion method>
In the frozen mercury intrusion method, first, in the same measurement of water permeability as described above, the measurement is repeated until the water permeability is substantially constant, that is, until the equilibrium water permeability is reached. About 1 to 2 g of material that passes through 4 mm (wire diameter 1.4 mm) and does not pass 2 mm (0.9 mm linear) on a sieve according to JIS-Z8801 The lightweight aerated concrete collected in the above is immersed in liquid nitrogen, frozen, and immediately filled in the sample tube is set in a pore size distribution measuring device (Pore Sizer 9320 manufactured by Micrometrics, USA), and the degree of vacuum is about 5 Pa. It measured on condition of this. Here, the differential pore size distribution by the mercury intrusion method is obtained by first-order differentiation of the integral curve of the pore amount with respect to the measured pore size. Further, the pressure measured when the contact angle between mercury and lightweight aerated concrete was 130 ° and the surface tension of mercury was 484 dyn / cm was converted into the pore diameter assuming that the pore shape was cylindrical. In the measurement of differential pore size by the frozen mercury intrusion method, it is important not to dry the infiltrated water in the lightweight aerated concrete by the equilibrium permeability measurement, so the temperature in the lightweight aerated concrete increases during the measurement. In order to prevent the frozen water from thawing, the sample tube may be cooled with dry ice or the like during the measurement, but when cooled from a 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 determined by a gas chromatograph (HP6890 manufactured by HEWLETT PACKARD) equipped with a thermal decomposition apparatus (PY2010D manufactured by Frontier Labs).
First, lightweight cellular concrete containing a water repellent before extraction is cut into a length of 40 mm, a width of 40 mm, and a length of 10 mm, dried in a hot air dryer (Tabba Espec Co., Ltd. PHH401) for 24 hours, and pulverized in a mortar. After that, it was placed in a desiccator containing a desiccant (silica gel) and allowed to stand for 24 hours in a state where the pressure was reduced by a vacuum pump (Vacuum Kiko Co., Ltd. DAH-60). Next, 5 mg of this dried lightweight cellular concrete was taken and measured with the above pyrolysis gas chromatograph, and the total peak area within a retention time of 10 minutes was determined from the resulting chromatogram.

On the other hand, in the case of measuring the extraction rate with water, 1 g of lightweight cellular concrete containing a water repellent previously dried in a hot air dryer at 60 ° C. for 24 hours in a mortar, and then added with 100 g of water (distilled water) 1 The mixture is stirred for a period of time to extract the water repellent contained in the lightweight aerated concrete, and then filtered to obtain a solid content. After air drying, the mixture is air-dried at 60 ° C. (Tabba Espec Co., Ltd. PHH401) for 24 hours. After drying, it was placed in a desiccator containing a desiccant (silica gel) and allowed to stand for 24 hours under reduced pressure with a vacuum pump (Dakin Kiko Co., Ltd. DAH-60). Next, 5 mg of lightweight cellular concrete extracted and dried by the same method as described above was measured with a pyrolysis gas chromatograph, and the total peak area within a retention time of 10 minutes was determined 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 pyrolysis apparatus is set to 800 ° C., the inlet temperature is 230 ° C., the detector temperature is 230 ° C., the column is set to be heated from 35 ° C. to 230 ° C. at a heating rate of 10 ° C./min, the carrier gas is helium, A flame ionization detector was used as a detector, and SUPEL-9PLOT (manufactured by SUPELCO) was used as a column. Similarly, in the case of measuring the extraction rate with ethanol or toluene, only the extraction solvent is changed from water to ethanol or toluene, and the rest is performed in the same manner as the measurement of the extraction rate with water.

<Content of organosilicon compound>
The amount of the organosilicon compound contained in the lightweight cellular concrete was determined by measurement with a gas chromatograph equipped with a thermal decomposition apparatus as described above. A calibration curve was prepared in advance for each organosilicon compound by the method described above. Next, the amount of the organosilicon compound in the lightweight cellular concrete containing an unknown amount of the organosilicon compound is measured by pyrolysis gas chromatograph in the same manner as described above, and the total peak area within the retention time of 10 minutes is obtained from the obtained chromatogram. Obtained and converted into the amount of organosilicon compound from the calibration curve.

<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, 2.5 parts by weight of dry gypsum, 7.5 parts by weight of quicklime, and 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 part by weight of aluminum powder was mixed and stirred for 30 seconds. Next, after pouring the obtained mortar slurry into the mold, it was kept at 60 ° C. for 90 minutes and pre-cured in a state where moisture evaporation was suppressed, and the resulting semi-cured lightweight cellular mortar block was played with a piano wire. Disconnected. The obtained semi-cured lightweight aerated concrete was placed in an autoclave, air in the autoclave was removed under reduced pressure, saturated steam was injected, and high temperature and high pressure curing was performed at 180 ° C. for 4 hours.

[Example 1]
After removing the lightweight cellular concrete obtained in the above-mentioned lightweight cellular concrete base material from the autoclave and leaving it sufficiently at room temperature until the temperature decreases, 16 sheets of the lightweight cellular concrete having a length of 600 mm, a width of 400 mm, and a thickness of 100 mm. Was again put in an autoclave (volume: 1.25 m ³ ) and reduced to a gauge pressure of -0.09 MPa with a water-sealed vacuum pump (Shinko Seiki Co., Ltd. SW-150). C. Saturated water vapor was injected, the inside of the autoclave was pressurized to a gauge pressure of 1.2 MPa over 50 minutes, kept in that state for 10 minutes, and then reduced to atmospheric pressure over 50 minutes. Immediately, saturated water vapor with a gauge pressure of 1.7 MPa and 208 ° C. was injected into another pressure vessel (volume: 0.375 m ³ ) containing 3850 g of propyltriethoxysilane (KBE-3033 manufactured by Shin-Etsu Chemical Co., Ltd.) The pressure vessel was set to 190 ° C. and the gauge pressure was set to 1.2 MPa. A mixed gas of propyltriethoxysilane vapor and water vapor obtained in the pressure vessel was injected into the autoclave, and the autoclave was gauged over 60 minutes. After pressurizing from a pressure of 0.0 MPa (atmospheric pressure) to 0.6 MPa, natural cooling was performed until room temperature was reached.

After the water-resistant lightweight cellular concrete obtained in this example was sufficiently dried, 3 sheets were randomly selected from 16 sheets, and each lightweight cellular concrete was cut in the vertical direction at the position of the horizontal half (width 200 mm). Thus, a sample having a length of 600 mm, a width of 200 mm, and a thickness of 100 mm was obtained. For the water repellency of the cut surface, the contact angle of water was measured at intervals of 10 mm from the vicinity of the surface in the thickness direction at a position of 300 mm in length in 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 central portion was 86.5 °. In addition, the water permeability was measured by installing four water permeability test instruments each having a funnel diameter of 75 mm on the same sample as the water contact angle, and calculating the 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. The amount of propyltriethoxysilane extracted with respect to water with a stirring time of 1 hour is 0.9 wt%, and the amount of propyltriethoxysilane extracted with respect to toluene is 0.7 wt% with respect to ethanol. The amount of propyltriethoxysilane extracted was 1.2 wt%. Moreover, 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 randomly determining the amount of propyltriethoxysilane contained in the three lightweight cellular concretes selected at random and cut in the vertical direction at half horizontal positions. The amount of propyltriethoxysilane contained in each lightweight cellular concrete was cut by shifting the above-mentioned three lightweight cellular concrete pieces by 5 mm in the lateral direction at a horizontal half position, 600 mm in length, 5 mm in width, Samples with a thickness of 100 mm were then crushed separately with a high-speed stamp mill (ANS-ONEPS ANS-143PS), then crushed with a mortar, and heated at 60 ° C with a hot air dryer (Tabaye Spec Corp.) After drying with PHH401) for 24 hours, it was placed in a desiccator containing a desiccant (silica gel), left under reduced pressure with a vacuum pump (Dakin Kiko Co., Ltd. DAH-60) for 24 hours, and then dried. 5 mg of the sample powder was measured with a pyrolysis gas chromatograph, and the propyltrie contained in each sample was measured from the above calibration curve. The amount of toxisilane was determined and taken as the average of three measurements. The average content of the obtained propyltriethoxysilane was 1.66 wt%.

[Example 2]
A water-resistant lightweight cellular concrete was obtained in the same manner as in Example 1 except that the organosilicon compound used was 1500 g of propyltriethoxysilane.
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 the vicinity of the surface to the center is 74. The water permeability was 566 cm ³ / m ² · day, and the equilibrium water permeability was 158 cm ³ / m ² · day. The amount of propyltriethoxysilane extracted with respect to water with a stirring time of 1 hour is 2.5 wt%, and the amount of propyltriethoxysilane extracted with respect to toluene is 1.8 wt% with respect to ethanol. The amount of propyltriethoxysilane extracted was 2.0 wt%. Further, 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 2974 g of propyltriethoxysilane and 156 g of hexyltriethoxysilane were used.
The water-resistant lightweight cellular concrete obtained in this example was measured for water contact 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. It was. Further, the total amount of propyltriethoxysilane and hexyltriethoxysilane extracted with respect to water having a stirring time of 1 hour is 2.2 wt%, and the amount of propyltriethoxysilane extracted with respect to toluene is 1. The amount of propyltriethoxysilane extracted with respect to 5 wt% 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 is 0.06 μm, and is 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 2974 g of propyltriethoxysilane and 156 g of octadecyltriethoxysilane were used as the organosilicon compounds to be used.
As a result of measuring the water contact of the water-resistant lightweight aerated concrete obtained in this example by the same method as in Example 1, the average value of the contact angle of water from the vicinity of the surface to the center is 89. The water permeability was 410 cm 3 / m 2 · day, and the equilibrium water permeability was 45 cm 3 / m 2 · day.

  The total amount of propyltriethoxysilane and octadecyltriethoxysilane extracted with respect to water with a stirring time of 1 hour 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% ethanol was 1.3 wt%. In addition, 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 is 0.04 μm, and the sum of the propyltriethoxysilane content and the octadecyltriethoxysilane content is It was 1.35 wt%.

[Example 5]
After placing 16 sheets of semi-cured lightweight cellular concrete having a length of 600 mm, a width of 400 mm, and a thickness of 100 mm obtained in the above-mentioned lightweight cellular concrete substrate production example into an autoclave (volume 1.25 m ³ ), steam curing, Without taking out lightweight cellular concrete from the autoclave, a gauge pressure of 1.7 MPa was continuously placed in another pressure vessel (volume: 0.375 m ³ ) containing 3850 g of propyltriethoxysilane (KBE-3033, manufactured by Shin-Etsu Chemical Co., Ltd.), Saturated water vapor at 208 ° C. was injected, the inside of the pressure vessel was set at 190 ° C. and the gauge pressure was 1.2 MPa, and the mixed gas of propyltriethoxysilane vapor and water vapor obtained in the pressure vessel was injected into the autoclave. The pressure in the autoclave is changed from 0.0 MPa (atmospheric pressure) to 0.6 MPa over 60 minutes. After pressurizing, it was naturally cooled to room temperature.

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 the vicinity of the surface to the center is 87. The water permeability was 476 cm ³ / m ² · day, and the equilibrium water permeability was 112 cm ³ / m ² · day. The amount of propyltriethoxysilane extracted with respect to water with a stirring time of 1 hour is 1.1 wt%, and the amount of propyltriethoxysilane extracted with respect to toluene is 2.5 wt% with respect to ethanol. The amount of propyltriethoxysilane extracted was 2.0 wt%. Further, 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, and the average content of propyltriethoxysilane was 1.54 wt%.

[Comparative Example 1]
After the lightweight cellular concrete obtained in the above-mentioned production example of lightweight cellular concrete substrate 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, and placed in a sealed container (volume 0.01 m ³ ). And after heating the sealed container and the attached piping to 180 ° C., the pressure is reduced to 300 Pa to remove most of the water contained in the lightweight cellular concrete, and then connected by a pipe that can be opened and closed with a valve. 100 g of propyltriethoxysilane was placed in a closed container (volume 0.01 m ³ ), and the pressure was reduced to 300 Pa, followed by heating to 180 ° C. to vaporize propyltrialkoxysilane to obtain a vapor pressure of 66000 Pa. Therefore, the valve was opened, and the vapor of the alkoxysilane was poured into a sealed container containing lightweight aerated concrete for about 2 minutes, and the pressure in the sealed container was set to 33000 Pa, and left as it was for 1 hour.

The water-repellent lightweight aerated concrete obtained in this comparative example was cut in a direction perpendicular to a horizontal 50 × longitudinal 100 surface at a half horizontal position to obtain a sample of 100 mm long, 50 mm wide, and 100 mm thick. For the water repellency of the cut surface, the contact of water was measured at 10 mm intervals from the vicinity of the surface in the thickness direction at a position of 50 mm in length of the sample. 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 water permeability is 567 cm ³ / m ² · day, and the equilibrium water permeability is It was 104 cm ³ / m ² · day. The amount of propyltriethoxysilane extracted with respect to water with a stirring time of 1 hour is 0.9 wt%, the amount of propyltriethoxysilane extracted with respect to toluene is 1.2 wt%, extracted with respect to ethanol. The amount of propyltriethoxysilane produced was 0.8 wt%. Moreover, the maximum peak of the differential pore size distribution obtained by the frozen mercury intrusion method from the sample immediately after the measurement of the equilibrium water permeability was 0.03 μm, and the average content of propyltriethoxysilane was 2.05 wt%. .
When the moisture in the lightweight cellular concrete was removed and treated with alkoxysilane vapor alone as in this comparative example, it was confirmed that the resulting lightweight cellular concrete was excellent in water resistance and greatly improved in water repellency. It was.

[Comparative Example 2]
In this comparative example, the lightweight cellular concrete is the above lightweight cellular concrete except that 0.5 part by weight of dimethyl silicone oil (KF-96 Shin-Etsu Chemical Co., Ltd.) is added to 100 parts by weight of solid content in the mortar slurry. It was obtained in the same manner as in the production example of the substrate . 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 °. 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 dimethyl silicone oil extracted with respect to water with a stirring time of 1 hour is 39.5 wt%, and the amount of dimethyl silicone oil extracted with respect to toluene is 12.5 wt% with respect to ethanol. The amount of dimethyl silicone oil extracted was 18.3 wt%. Moreover, 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 cannot ensure sufficient water resistance.

[Comparative Example 3]
In this comparative example, the lightweight cellular concrete is the same as the lightweight cellular concrete base except that 3 parts by weight of 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. Obtained in the same manner as the manufacture of the material . 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. As a result, the average value of the water contact angle from the vicinity of the surface to the center was 125.1. °, water permeability ^{is, 602cm 3 / m 2 · day} , the equilibrium water permeability was 294cm3 ^/ m 2 · day. In addition, the amount of the alkyl-modified silicone oil extracted with respect to water with a stirring time of 1 hour 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 alkyl-modified silicone oil extracted with respect to ethanol was 14.1 wt%. Moreover, 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 0.35 μm.
The lightweight cellular concrete obtained by this comparative example has not only water resistance but also water repellency that is greatly improved.

[Comparative Example 4]
In this comparative example, the lightweight cellular concrete is the same as the lightweight cellular concrete base except that 2 parts by weight of 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. Obtained in the same manner as the manufacture of the material . 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. As a result, the average value of the water contact angle 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.
In addition, the amount of the alkyl-modified silicone oil extracted with respect to water with a stirring time of 1 hour is 1.3 wt%, and the amount of the alkyl-modified silicone oil extracted with respect to toluene is 29.4 wt% in ethanol. On the other hand, the amount of the alkyl-modified silicone oil extracted was 14.0 wt%. Moreover, 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 0.51 μm.
The lightweight cellular concrete obtained by this comparative example has not only water resistance but also water repellency that is greatly improved.

[Comparative Example 5]
In this comparative example, the lightweight cellular concrete is the same as the lightweight cellular concrete base except that 1 part by weight of 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. Obtained in the same manner as the manufacture of the material . Here, the size of the lightweight cellular concrete was 600 mm in length, 400 mm in width, and 100 mm in thickness.
As a result of measuring the contact angle of water 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 103 °, and the lightweight cellular concrete obtained in this comparative example is 103 °, The water permeability was 1188 cm ³ / m ² · day, and the equilibrium water permeability was 466 cm ³ / m ² · day.
The amount of the alkyl-modified silicone oil extracted with respect to water with a stirring time of 1 hour is 8.5 wt%, and the amount of the alkyl-modified silicone oil extracted with respect to toluene is 26.3 wt% with respect to ethanol. The amount of the alkyl-modified silicone oil extracted in this manner was 13.1 wt%. Moreover, 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 0.83 μm.
It was confirmed that the lightweight cellular concrete obtained by this comparative example was inferior in water resistance although the water repellency was improved.

[Comparative Example 6]
In this comparative example, the lightweight cellular concrete is the same as the lightweight cellular material 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. It was obtained in the same manner as the production of the concrete substrate . 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 with a stirring time of 1 hour is 32.4 wt%, and the amount of the alkyl-modified silicone oil extracted with respect to toluene is 15.4 wt% with respect to ethanol. The amount of the alkyl-modified silicone oil extracted in this manner was 11.5 wt%. Moreover, 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 0.91 μm.
It was confirmed that the lightweight cellular concrete obtained by this comparative example was inferior in water resistance although the water repellency was improved. Moreover, it was confirmed that the extraction amount with respect to water was very large.

  The lightweight aerated concrete of the present invention is a lightweight aerated concrete having excellent water resistance and excellent paintability without impairing the light weight and excellent heat insulation performance possessed by the lightweight aerated concrete, so it is suitable in the field of building materials. Available to:

Claims (7)

The water contact angle of the cut surface perpendicular to the surface of the lightweight cellular concrete is in the range of less than 100 ° and 50 ° or more, and the water permeability at the cut surface of the lightweight cellular concrete is 1000 cm ³ / m ² · day or less. Water-resistant lightweight cellular concrete characterized by that. ^2. The water-resistant lightweight cellular concrete according to claim 1, wherein the equilibrium water permeability in a cut surface perpendicular to the surface of the lightweight cellular concrete is 450 cm ³ / m ² · day or less. 3. The differential pore diameter distribution obtained by the frozen mercury intrusion method immediately after the equilibrium water permeability measurement, wherein the pore diameter having the maximum peak is in the range of 0.01 to 0.1 [mu] m. Water-resistant lightweight cellular concrete described in 1. The amount of water repellent extracted by water is 10 wt% or less of the amount of water repellent contained in the lightweight cellular concrete, and the amount of water repellent extracted by toluene and ethanol is contained in the lightweight cellular concrete. The water-resistant lightweight cellular concrete according to any one of claims 1 to 3, wherein the content is 10 wt% or less of the amount. The water-resistant lightweight cellular concrete according to claim 1, 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 represents an alkyl group. N represents an integer of 1 to 3. When n is 2 or more, R1 may be the same or different, and n is In the case of 2 or less, each R2 may be the same or different.) Put lightweight cellular concrete in an autoclave, and introducing steam, impregnated with steam inside said light amount cellular concrete steps down in the autoclave, from the outside of the autoclave, a mixed gas containing water vapor and the water-repellent agent vapor into the autoclave A method for producing water-resistant lightweight cellular concrete, characterized by injecting and processing lightweight cellular concrete.
After semi-cured lightweight aerated concrete is placed in the autoclave and steam-cured at high temperature and high pressure, the steam is continuously removed from the outside of the autoclave without removing the lightweight aerated concrete at a temperature of 100 to 250 ° C. and a pressure of 0.1 to 4 MPa. A method for producing water-resistant lightweight cellular concrete, which comprises treating a lightweight cellular concrete by injecting a mixed gas containing water and water repellent vapor into an autoclave.