JP2005179148A - Lightweight cellular concrete and its producing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide lightweight cellular concrete which has a bulk specific gravity of ≥0.2 and <0.45 lower than that of a conventional one, and has strength suitable as a building material, and which hardly generates strain and exhibits resistance to change of the surrounding environment because it has good follow-up property to the change of surrounding environment; and to provide a method for producing the same. <P>SOLUTION: The lightweight cellular concrete is composed of tobermorite and characterized in that the bulk specific gravity is ≥0.2 and <0.45, the accumulated pore volume vI of pores having pore diameters within a range of 0.006-1 μm is 0.7-2.5 cm<SP>3</SP>/g in the pores measured by a mercury penetration method, and the accumulated pore volume vII of pores having pore diameters within a range of 10-400 μm, measured by the mercury penetration method, is 0.09-1.0 cm<SP>3</SP>/g. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to lightweight cellular concrete that is lightweight and suitable as a building material, and a method for producing the same. More specifically, lightweight cellular concrete that is lighter than conventional lightweight cellular concrete, has the strength required as a building material, and is resistant to changes in the surrounding environment because it is less likely to be distorted inside, and The present invention relates to a method for efficiently producing the lightweight cellular concrete with excellent productivity.

Lightweight cellular concrete has a bulk specific gravity of 0.5-0.6 and contains a large amount of highly crystalline tobermorite (5CaO · 6SiO ₂ · 5H ₂ O). It has excellent long-term weather resistance, fire resistance, and indestructibility. Moreover, since it is lightweight and excellent in workability, construction is easy, and it is widely used as an outer wall material, a floor material, an inner wall material, etc. of a building.
Lightweight cellular concrete is mainly made of cement and quartzite powder, and quick lime powder, gypsum, etc. are added to this as needed, water is added to form a slurry, and foamed with a foaming agent such as aluminum powder under atmospheric pressure. It is manufactured by molding in a mold and curing in an autoclave. Compressive strength of lightweight concrete typically ranges from 4~5N / mm ^2, bending strength is in the range of 1 to 1.5 N / mm ^2.

In recent years, lightweight foam concrete with a lower specific gravity has been maintained, while maintaining the features of conventional lightweight cellular concrete, from the viewpoint of further weight reduction of buildings, improved safety during field work and reduced burden on workers. It has been demanded.
As low-weight specific lightweight lightweight concrete, one containing a larger amount of bubbles due to the foaming agent is generally used. As a means for realizing a low specific gravity, when many bubbles are contained, the bubble diameter becomes enormous, and the ratio of coarse bubbles due to the blowing agent to the entire volume increases, leading to a significant decrease in strength.
In order to improve them, Patent Document 1 includes a thermoplastic resin, Patent Document 2 includes an alkaline earth metal carbonate, Patent Document 3 includes a silica having a large specific surface area. Low-specific gravity lightweight cellular concrete manufactured using powder is disclosed.

However, even with these techniques, the reduction in compressive strength due to the reduction in bulk specific gravity cannot be avoided. For example, when the bulk specific gravity is 0.35 to 0.40, the compressive strength is about 1.5 to 3.25 N / mm ^2. It is weaker than conventional lightweight cellular concrete.
On the other hand, Patent Document 4 discloses a lightweight concrete with a low specific gravity in which the independence of bubbles is increased and the bubbles are uniformly distributed. In this document, the specific gravity is 0.35, the compressive strength is 4.1 N / mm ² , the specific gravity is 0.4, and the compressive strength is 4.2 N / mm ^2. Physical properties are obtained.
Patent Document 5 discloses a lightweight concrete with a low specific gravity that improves the content of tobermorite crystals and makes the pore size distribution uniform. In the document, compressive strength 5.2 N / mm ² in the specific gravity 0.35, also called compressive strength 6.8N / mm ² in the specific gravity 0.4, a low specific gravity, the intensity range of the conventional lightweight concrete Entering physical properties are obtained.

Conventionally, lightweight aerated concrete is a fate of building materials, exposed to rainwater due to the weather during construction work, wet from the next day and dried by sunshine from the next day, and in high humidity environments in winter and in winter They are usually exposed to a low humidity environment and various natural environments around them depending on the season and weather.
Normal concrete has a specific gravity of about 2.0, whereas lightweight aerated concrete has a specific gravity of 0.5 to 0.6, but its weight reduction is realized by containing many voids inside. ing. In lightweight cellular concrete, about 80% of voids are voids. Therefore, more water absorption occurs when exposed to rainwater than normal concrete.

Lightweight cellular concrete is characterized by its light weight and excellent water resistance, so there is no problem in water absorption itself, but the speed of water absorption and the subsequent drying speed are important. Although the place where water has been absorbed is minute, expansion occurs. If the water absorption speed is high, a uniform water content from the surface to the center is realized at an early stage, so that distortion due to the water content distribution does not occur inside. However, when the water absorption rate is low, there is a difference in strain between the vicinity of the surface and the center, and in some cases, there is a concern that cracks or the like may occur due to the generated strain. The same applies to drying when exposed to sunlight after water absorption.
Conventional lightweight cellular concrete having a bulk specific gravity of 0.5 to 0.6 has been proven to withstand such environmental changes in a long track record of use. However, lightweight cellular concrete having a lower bulk specific gravity, for example 0.2 or more and less than 0.45, has a larger amount of voids than before. Therefore, the amount of water absorption increases and distortion is likely to occur, and at the same time, the solid portion that bears the stress generated along with the occurrence of distortion is small, and the amount of distortion generated is also large. Therefore, lightweight cellular concrete having a low bulk specific gravity is required to follow changes in the surrounding environment at an earlier stage than conventional lightweight cellular concrete.

The low specific gravity lightweight cellular concrete disclosed in the above-mentioned patent document, both for those having a problem that the strength is not sufficient, and those having physical properties that fall within the strength range of conventional lightweight cellular concrete, There was a problem that early follow-up to changes in the surrounding environment was not sufficient.
Furthermore, as for the method of producing lightweight cellular concrete having a low specific gravity, in Patent Document 4, it is necessary to produce new equipment for foaming under reduced pressure and then pre-curing under the same reduced pressure. There was a problem that the performance decreased.

JP 60-33271 A JP 62-162679 A JP 2001-253758 A JP 58-15061 A International Publication No. 02/066396 Pamphlet

  The present invention has a bulk specific gravity of 0.2 or more and less than 0.45, which is lighter than conventional lightweight cellular concrete, has a strength suitable as a building material, and has good follow-up to changes in the surrounding environment. Accordingly, it is an object of the present invention to provide a lightweight cellular concrete that is resistant to distortion and is resistant to changes in the surrounding environment, and a method for producing the lightweight cellular concrete.

In order to solve the above problems, the present inventors have focused on the pore structure of lightweight cellular concrete, and have intensively studied on the production raw material structure for realizing it, and as a result, have completed the present invention. It came.
That is, the present invention is as follows.
(1) Cumulative pore volume vI mainly composed of tobermorite and having a bulk specific gravity of 0.2 or more and less than 0.45 and having a pore diameter in the range of 0.006 μm to 1 μm among pores measured by mercury porosimetry. There 0.7cm ³ /g~2.5cm ³ / g, and the and the pore diameter measured by mercury porosimetry is cumulative pore volume vII ranging 10μm~400μm 0.09cm ³ / g~1. Lightweight cellular concrete characterized by 0 cm ³ / g.

(2) The accumulated pore volume vI having a pore diameter in the range of 0.006 μm to 1 μm is f ₁ (d) cm ³ / g or more represented by the mathematical expressions (1) and (2) according to the bulk specific gravity (d), _and, lightweight cellular concrete according to equal to or less than ^{f 2 (d) cm 3 /} g (1).
f ₁ (d) = 0.15 / d + 0.37 (1)
f ₂ (d) = 0.15 / d + 1.75 (2)
(3) In the differential pore distribution curve measured by mercury porosimetry, the pore diameter has at least one maximum value in the range of 10 to 400 μm, and the pore diameter that gives the maximum value is in the range of 40 to 200 μm. The lightweight cellular concrete according to (1) or (2), wherein

(4) Among the pores measured by the mercury intrusion method, the logarithmic distribution width at the height of 1/4 of the maximum value of the differential pore distribution curve in the pore diameter range of 0.006 μm to 1 μm is 0.4 to The lightweight cellular concrete according to any one of (1) to (3), which is 1.4.
(5) The lightweight cellular concrete according to any one of (1) to (4), wherein the bulk specific gravity is 0.23 or more and 0.4 or less.
(6) Add metal aluminum powder as a foaming agent to an aqueous slurry containing at least siliceous raw material, cement and calcareous raw material, inject into a mold, pre-cured, and then autoclave cured, bulk specific gravity 0.2 to 0.45 In a method for producing a lightweight lightweight aerated concrete, the ratio of the calcareous raw material to the cement is 0.3 to 1.0 by weight, and the slurry containing the foaming agent is based on the amount of water in the slurry. A method for producing a lightweight cellular concrete, comprising 0.001 to 0.1% by weight of a surfactant.

(7) The method for producing lightweight lightweight concrete according to (6), wherein the weight ratio of water to the total solid raw material in the slurry before being poured into the mold is 0.78 or more and 2.66 or less. .
(8) The method for producing lightweight lightweight concrete according to (6) or (7), wherein a crystalline siliceous material having a Blaine specific surface area of 5000 to 15000 cm ² / g is used as the siliceous material.
(9) The method for producing lightweight cellular concrete according to any one of (6) to (8), wherein aluminum sulfate or a hydrate thereof and other sulfuric acid compounds are added to the aqueous slurry.
(10) In any one of (6) to (9), the siliceous raw material, cement, and calcareous raw material are mixed at a CaO / SiO ₂ molar ratio of 0.5 to 1.0. The manufacturing method of the lightweight lightweight concrete of description.

  The lightweight aerated concrete of the present invention has a bulk specific gravity of 0.2 or more and less than 0.45, which is lighter than conventional lightweight aerated concrete, and has a strength suitable as a building material, and can follow changes in the surrounding environment. It is highly useful because it is high, and it also realizes lighter buildings, improved safety during field work, and reduced burden on workers.

Hereinafter, the present invention will be described in detail.
The lightweight cellular concrete of the present invention is mainly characterized by being mainly composed of tobermorite (5CaO.6SiO ₂ .5H ₂ O). Tobermorite is one of typical crystalline calcium silicate hydrates usually found in structures such as conventional lightweight cellular concrete, and takes a plate-like or strip-like particle form.
In the lightweight cellular concrete of the present invention, whether or not tobermorite is the main component is determined as follows by using scanning electron microscope observation of the fracture surface of the lightweight cellular concrete and powder X-ray diffraction in combination.

First, in powder X-ray diffraction, there is no other diffraction peak exceeding the strongest line (220) plane of tobermorite. However, when crystalline silica, calcium carbonate, and gypsum coexist with tobermorite, the strongest line of these substances exceeds the strongest line of tobermorite due to the high crystallinity of these coexisting substances, even if tobermorite is the main component. There is a case.
Therefore, secondly, using a scanning electron microscope, observe 20 random locations of the matrix other than the coarse bubbles by the foaming agent in the region of 35.4 μm × 18.9 μm with a microscope magnification of 2500 times. If the average of the area ratio where the plate-like or strip-like tobermorite particles are observed is 50% or more, it is mainly composed of tobermorite. The average of the area ratio is preferably 60% or more, and more preferably 80% or more.

Here, the coarse bubble portion refers to a coarse bubble and a region from the coarse bubble to a surrounding area of about 5 μm, and a region where tobermorite is likely to be generated due to the presence of free space. With a plate-like or strip-like particle, the distance between two surfaces substantially parallel to each other corresponds to the minimum length of the particle, and the maximum length of the particle is the minimum length (hereinafter referred to as the thickness). This is a particle that is 5 times or more. The maximum length and thickness here are projection lengths in two dimensions. The size of these tobermorite particles is not limited, but the maximum length is preferably several μm to 10 μm.
Usually, tobermorite often coexists with low crystalline calcium silicate hydrate (hereinafter abbreviated as CSH). Although CSH is known to take various particle forms, it is usually distinguishable from tobermorite particles under an electron microscope because it takes a fibrous, granular, or massive particle form. Such CSH may be contained within a range that does not destroy the basic skeleton of tobermorite, but CSH reduces various necessary performances as building materials such as strength, weather resistance, durability, etc. It is preferable not to contain. Furthermore, a small amount of lightweight aggregate, reinforcing fiber, resin, and the like can be contained within a range that does not destroy the basic skeleton of tobermorite.

Even when the strongest line of crystalline silica such as quartzite exceeds the strongest line of tobermorite and the above-mentioned scanning electron microscope observation is made and it is determined that it is mainly composed of tobermorite, in the powder X-ray diffraction, the (220) plane of tobermorite The diffraction peak intensity is preferably ½ or more of the diffraction peak intensity of the (101) plane of quartz, more preferably 3/5 or more, and most preferably 2/3 or more. The diffraction peak intensity of the (220) plane of tobermorite and the diffraction peak intensity of the (101) plane of quartz are values including the background intensity.
Usually, lightweight aerated concrete contains the silica which remained unreacted among the silica preferably used as a raw material. Conventionally, these residual silica stones are considered to have an effect of preventing the progress of cracks, and many of them have been deliberately left behind. However, in light-weight concrete having a bulk specific gravity of 0.2 or more and less than 0.45, which has a lower specific gravity than the conventional one, the strength tends to be improved when the residual amount of silica is small.

The bulk specific gravity of the lightweight cellular concrete of the present invention is 0.2 or more and less than 0.45, preferably 0.23 to 0.40, more preferably 0.25 to 0.40. The bulk specific gravity here refers to the bulk specific gravity when dried at 105 ° C. for 24 hours, that is, the absolute dry specific gravity. If the bulk specific gravity is less than 0.2, strength suitable as a building material cannot be obtained. If the bulk specific gravity is 0.45 or more, the lightness is not sufficient. I can't.
In lightweight concrete of the present invention, among the pores as measured by mercury porosimetry, the accumulated pore volume vI range pore size of 0.006μm~1μm, 0.7cm ³ /g~2.5cm ³ / it is necessary g is preferably the cumulative pore volume vI is, _f 1 of the formula by a bulk specific gravity (d) (1) and formula ^{(2) (d) cm 3} / g or more _f 2 ( d) cm ³ / g or less.
f ₁ (d) = 0.15 / d + 0.37 (1)
f ₂ (d) = 0.15 / d + 1.75 (2)

Here, the mercury intrusion method is a method in which mercury is injected into the cured body and the distribution of the pore diameter is measured from the relationship between the pressure and the amount of penetration, and the pore shape is assumed to be cylindrical. Calculated. Therefore, the measurable range of the pore diameter is in the range of 6 nm to 500 μm, but this value does not represent the actual pore diameter, but is used as an index of the size of the gap between the constituent materials. In particular, it is an effective analysis means when describing the pore structure of the lightweight cellular concrete of the present invention.
The accumulated pore volume is an integral value of the pore amount measured with respect to the pore diameter. The cumulative pore volume vI having a pore diameter in the range of 0.006 μm to 1 μm is an integral value of the pore amount measured with respect to the pore diameter in the range of 0.006 μm to 1 μm. It is known that lightweight cellular concrete has pores in this pore diameter range in a portion (hereinafter referred to as a matrix) that forms a skeleton that bears stress against external force.

  Conventionally, as lightweight lightweight concrete with a low specific gravity, those containing a larger amount of bubbles due to the foaming agent are generally used than lightweight lightweight concrete with a specific gravity of 0.5 to 0.6. In the present invention, unlike the conventional general method, the amount of bubbles caused by the foaming agent is reduced to a conventional specific gravity by containing a large amount of pores in the matrix portion, in order to prevent a decrease in strength due to an increase in the amount of bubbles. While maintaining the same degree as 0.5 to 0.6 lightweight cellular concrete, a lightweight concrete with a low specific gravity of 0.2 to less than 0.45 is achieved.

Therefore, there is a cumulative pore volume vI directly related to the bulk density in the range of 0.006Myuemu～1myuemu, if outside the range of 0.7cm ³ /g~2.5cm ³ / g Intended Thus, lightweight cellular concrete having a sufficient bulk specific gravity of 0.2 or more and less than 0.45 cannot be obtained. Since the integrated pore volume vI is directly related to the bulk specific gravity of the lightweight cellular concrete, a more preferable range of the integrated pore volume vI varies depending on the bulk specific gravity. A preferable range for obtaining lightweight cellular concrete having a bulk specific gravity of 0.2 or more and less than 0.45 is f ₁ (d) in which the integrated pore volume vI is represented by the formulas (1) and (2) according to the bulk specific gravity (d). ) Cm ³ / g or more and f ₂ (d) cm ³ / g or less.
f ₁ (d) = 0.15 / d + 0.37 (1)
f ₂ (d) = 0.15 / d + 1.75 (2)

Thus, the lightweight cellular concrete of the present invention contains a large amount of pores while maintaining the amount of bubbles caused by the foaming agent at the same level as the conventional lightweight cellular concrete having a specific gravity of 0.5 to 0.6. doing. Therefore, for example, the cumulative pore volume vI in the range of 0.006 μm to 1 μm being less than 0.7 cm ³ / g means containing more bubbles than the conventional lightweight cellular concrete, resulting in a decrease in strength. Happens. Moreover, that the cumulative pore volume vI exceeds 2.5 cm ³ / g means that it contains only a smaller amount of bubbles than the conventional lightweight cellular concrete, and the strength expression is sufficient, but the amount of bubbles is small. As a result, the follow-up to the surrounding environment, for example, the drying speed becomes slow.

In lightweight concrete of the present invention, it is necessary that the pore diameter measured by mercury porosimetry is cumulative pore volume vII ranging 10μm~400μm is 0.09cm ³ /g~1.0cm ³ / g In addition, it is preferable that the cumulative pore volume in the range of the pore diameter of ³⁰ μm to 400 μm is 0.08 cm ³ / g to 0.8 cm ³ / g. Lightweight cellular concrete having a low bulk specific gravity of 0.2 or more and less than 0.45 has a larger amount of voids than conventional lightweight cellular concrete. For this reason, the amount of water absorption increases, distortion is likely to occur, and the amount of generated strain increases because there are few solid parts that bear the stress that is generated when the distortion occurs.
In such lightweight lightweight concrete with low bulk specific gravity, the cumulative pore volume vII in the range of 10 μm to 400 μm in pore diameter is not less than 0.09 cm ³ / g, so that it can remarkably follow the surrounding environment. Improvements have been found for the first time by the present invention. The environmental followability is, for example, that the water absorption speed is high, and thus the non-uniformity of the moisture distribution inside the lightweight cellular concrete is less likely to occur, so that cracks are less likely to occur when exposed to rainwater. When the cumulative pore volume vII is less than 0.09 cm ³ / g, insufficient followability to the surrounding environment, and when more than 1.0 cm ³ / g, the followability of the surrounding environment is sufficient Although there is a decrease in strength.

The reason why the followability to the surrounding environment is improved when the integrated pore volume vII in the range of 10 μm to 400 μm is large is not clear, but the pores observed in this range minimize the decrease in strength. It is presumed that water and water vapor channels are provided while suppressing.
Cumulative pore volume vII of range pore size of 10μm~400μm, it is important absolute amount of 0.09cm ³ /g~1.0cm ³ / g, does not depend on the clear on the bulk specific gravity of lightweight concrete However, when the target bulk specific gravity is lower, there is a tendency that a larger amount of the integrated pore volume vII is required in order to improve the followability to the surrounding environment.
The lightweight cellular concrete of the present invention has at least one maximum value in a pore diameter range of 10 to 400 μm in a differential pore distribution curve measured by a mercury intrusion method, and a pore diameter giving the maximum value of 40 to 40 μm. It is preferably in the range of 200 μm. The differential pore distribution is obtained by first-order differentiation of the pore volume integrated curve with respect to the measured pore diameter. The differential pore distribution curve has at least one maximum value when the pore diameter is in the range of 10 to 400 μm, and the pore diameter that gives the maximum value is in the range of 40 to 200 μm. The nature is further improved.

The reason why the distribution contributes not only to the cumulative pore volume vII in the range of 10 μm to 400 μm but also the distribution to the change in the surrounding environment is not clear, but the range of 40 to 200 μm as the flow path of water or water vapor It is presumed that the followability is improved due to the large amount of pores having these preferred pore sizes.
The lightweight cellular concrete of the present invention has a logarithmic distribution width at a height of ¼ of the maximum value of the differential pore distribution curve in the pore diameter range of 0.006 μm to 1 μm among the pores measured by the mercury intrusion method. Is preferably 0.4 to 1.4, more preferably 0.4 to 1.2, and most preferably 0.4 to 1.1.

Of the pores measured by the mercury intrusion method, the logarithmic distribution width (logarithm 1/4 value width) at the height of 1/4 of the maximum value in the differential pore distribution curve in the pore diameter range of 0.006 μm to 1 μm Is one index representing the spread of the pore distribution in the matrix, and the width of the pore diameter distribution at a height of ¼ of the maximum value in the differential pore distribution curve of 0.006 μm to 1 μm is displayed in logarithm. It is a thing.
The calculation method is shown in FIG. When there are two pore diameters giving a height that is 1/4 of the maximum value in the differential pore distribution curve obtained by first-order differentiation of the pore volume integrated curve with respect to the pore diameter measured by the mercury intrusion method, Assuming that A ₂ and A ₁ are in descending order, the logarithmic quarter value width is the difference between the common logarithms of A ₂ and A ₁ . When A ₂ is not present in the range of 0.006 μm to 10 μm, A ₂ is 10 μm, and when A ₁ is not present, A ₁ is 0.006 μm.

In addition, as shown in FIG. 2, when the pore diameter is in the range of 0.006 μm to 1 μm and there are more than two pore diameters giving a height of ¼ of the maximum value in the differential pore distribution curve, among the biggest difference in common logarithm of common logarithm and the minimum pore diameter a ₁ of the pore diameter a _2. When the logarithmic quarter value width exceeds 1.4, the pore distribution in the matrix has a wide distribution, indicating that the uniformity is low. Therefore, local stress concentration tends to occur, and there is a tendency to cause a decrease in strength. The smaller the log 1/4 value width is, the more the physical properties such as strength are improved, but in the present invention, 0.4 or more is preferable.
The lightweight cellular concrete of the present invention may contain 0.1 to 3.0% by weight of a water-repellent substance as necessary. Water-repellent substances include siloxane compounds, alkoxysilane compounds, fatty acids, fatty acid salts, epoxy resins, urethane resins, silicone resins, vinyl acetate resins, acrylic resins, resin emulsions such as styrene-butadiene resins, etc. It is a water-repellent substance, and one or a mixture of two or more of them can be used.

Among these, in particular, siloxane compounds, that is, silicone oils in which a part of methyl groups of polydimethylsiloxane or polydimethylsiloxane are substituted with hydrogen, phenyl groups, trifluoropropyl groups, etc., alkoxysilane compounds, that is, methyltriethoxysilane. It is preferable to use alkylalkoxysilane compounds such as ethyltriethoxysilane, propyltriethoxysilane, and isobutyltriethoxysilane.
The content of the water repellent material is preferably 0.1 to 3.0% by weight, more preferably 0.5 to 2.0% by weight. If the content of the water-repellent substance is less than 0.1% by weight, water repellency cannot be expected. If it exceeds 3.0% by weight, the tobermorite production reaction is adversely affected and the strength tends to be lowered.

The lightweight cellular concrete of the present invention can contain reinforcing fibers in an amount of 0.05 to 3 vol% as required. Reinforcing fibers are inorganic fibers such as alkali-resistant glass fibers, carbon fibers, stainless steel fibers, ceramic fibers, asbestos fibers, and organic fibers such as aramid fibers, vinylon fibers, and polypropylene fibers. Among these, one kind or two or more kinds are used. It can be used as a mixture. In order to obtain the target performance, aramid fibers, alkali-resistant glass fibers and carbon fibers are preferable, and para-based aramid fibers are more preferable.
The fiber length of the reinforcing fiber is usually 1 to 20 mm, preferably 3 to 10 mm, more preferably 5 to 8 mm. The content of the reinforcing fiber is preferably 0.05 to 3 vol%, more preferably 0.1 to 2 vol%, based on the volume of the cured body including the voids. When the reinforcing fiber content is less than 0.05 vol%, a sufficient reinforcing effect is not exhibited. On the other hand, if it exceeds 3 vol%, fiber holes are easily formed during mixing, and uniform dispersion in the cured product becomes difficult.

Below, the example of the manufacturing method of the lightweight cellular concrete of this invention is demonstrated.
The method for producing lightweight aerated concrete according to the present invention includes adding an aluminum powder as a foaming agent to an aqueous slurry containing at least a siliceous raw material, a cement and a calcareous raw material, injecting them into a mold, precuring, curing an autoclave, The basic configuration is to produce lightweight cellular concrete having a specific gravity of 0.2 or more and less than 0.45.
In the method for producing lightweight aerated concrete according to the present invention, the ratio of the calcareous raw material to the cement is 0.3 to 1.0, preferably 0.4 to 0.8, before being poured into the mold. The slurry is characterized by containing a surfactant in an amount of 0.001 to 0.1% by weight with respect to water in the slurry containing a foaming agent. By satisfying such conditions, it is extremely practical because it has a strength suitable as a building material while being lighter than conventional lightweight cellular concrete and has high followability to changes in the surrounding environment. It has been found by the present inventors for the first time that a lightweight aerated concrete can be efficiently produced with high productivity.

When the ratio of the calcareous raw material to the cement is less than 0.3 by weight, a lightweight cellular concrete having a low bulk specific gravity, which is the object of the present invention, has a low tobermorite crystal growth, so that sufficient compressive strength cannot be obtained. . On the other hand, when the weight ratio exceeds 1.0, the expression of compressive strength is sufficient, but the amount of pores in the range of 1 to 400 μm measured by the mercury intrusion method is not sufficiently formed even when a surfactant is contained. . Therefore, there arises a problem that the following speed to the surrounding environment change, for example, the water absorption speed becomes slow. Furthermore, the speed of pre-curing becomes slow and productivity is lowered.
When the content of the surfactant is less than 0.001% by weight with respect to the water in the slurry containing the foaming agent, the amount of pores in the range of 10 to 400 μm measured by the mercury intrusion method is not sufficiently formed. Therefore, there arises a problem that the following speed to the surrounding environment change, for example, the water absorption speed becomes slow. On the other hand, when the content of the surfactant exceeds 0.1% by weight with respect to water, fine cracks are likely to occur inside the lightweight cellular concrete. Even when cracks do not occur, the amount of pores in the range of 10 to 400 μm measured by the mercury intrusion method is too large, resulting in a decrease in compressive strength.

The reason why pores are formed in the range of 10 to 400 μm as measured by the mercury intrusion method with a surfactant is not clear, but to change the surface tension of water due to the temperature of the slurry and the effect of dissolved ions. It is presumed that things such as changing the size of bubbles formed by the foaming agent and causing appropriate connections between the bubbles are occurring.
When manufacturing lightweight lightweight concrete with a lower bulk specific gravity than conventional lightweight cellular concrete, it is easily affected by dissolved ions, so the surfactant acts effectively and is measured by the mercury intrusion method. In order to form a pore amount in the range of 10 to 400 μm, it is estimated that the ratio of the calcareous raw material to the cement needs to be in a specific range different from the conventional one.

The timing of adding the surfactant is not limited, but it is preferable to add at least all the solid raw materials including siliceous raw materials, cement and calcareous raw materials and water and before adding the metal aluminum powder. .
The type of the surfactant is not limited, but cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, and potassium oleate can be used. The addition form of the surfactant is not limited, and methods such as adding as a powder or adding as a slurry previously mixed with water are used.
In the present invention, the weight ratio of water to the total solid raw material in the slurry before pouring into the mold is preferably 0.78 or more and 2.66 or less, and 0.91 or more and 1.67 or less. More preferred.

The true specific gravity of inorganic substances such as tobermorite crystals constituting the lightweight cellular concrete is about 2.5, but the bulk specific gravity of the lightweight cellular concrete is 0.5. This is because many voids are included inside. In the conventional lightweight cellular concrete, the volume fraction of voids is about 80%. The voids of 80% are cellular voids (about 50%) formed by a foaming agent such as aluminum powder. The hydrate produced by the reaction of the solid raw material fills the volume occupied by water, but is composed of fine voids (about 30%) called pores that remain without being filled.
The production method of the present invention does not increase the amount of bubbles by increasing the amount of aluminum powder added to reduce the bulk specific gravity of 0.2 to 0.45, but approximates the bubble voids relative to the total volume. While maintaining 50%, the pores are increased by the target bulk specific gravity, that is, the amount of water used is increased.

Therefore, in the light weight concrete manufacturing method of the present invention having a bulk specific gravity of 0.2 or more and less than 0.45, preferably 0.3 or more and 0.4 or less, the weight ratio of water to the total solid raw material used is preferable. . More preferably, it is necessary to change the weight ratio of water with respect to the total solid raw material used according to the target bulk specific gravity. Therefore, the weight ratio of water to the total solid raw material to be used is W ₁ or more obtained from the bulk specific gravity (d) of the intended lightweight cellular concrete using the following formula (3), and the following formula (4) is used. More preferably, it is W ₂ or less.
W ₁ = 0.483 / d−0.296 (3)
W ₂ = 0.591 / d−0.296 (4)
Examples of siliceous raw materials used in the present invention include crystalline silica, quartz sand, quartz and rocks having a high content thereof, diatomaceous earth, silica fume, fly ash, blast furnace slag, paper sludge incinerated ash, or natural clay. Minerals or fired products thereof. It is preferable to use a crystalline raw material mainly as a siliceous raw material, and it is more preferable to use a crystalline siliceous raw material having a Blaine specific surface area of 5000 to 15000 cm ² / g as a main component. Examples of crystalline siliceous raw materials include quartzite, quartz sand, quartz, and rocks having a high content thereof.

When the Blaine specific surface area of the siliceous raw material is in the above range, the reactivity in the autoclave is improved, and a large amount of tobermorite with high crystallinity is generated, contributing to the development of strength. The Blaine specific surface area of 5000cm less than ² / g, showed no contribution to improving the strength exceeds 15000 cm ² / g, a stable amorphous for reactivity in an autoclave is too high in an autoclave heating process There is a tendency to reduce the crystallinity of tobermorite by forming a compound. When the pre-curing time is shortened, it is preferable to use an amorphous silicic acid raw material represented by silica fume, fly ash, blast furnace slag, and paper sludge incinerated ash having high reactivity during pre-curing.

The cement used in the present invention is mainly composed of a silicic acid component and a calcium component such as ordinary Portland cement, early-strength Portland cement, and belite cement.
Examples of the calcareous raw material in the present invention include quick lime and slaked lime.
Moreover, in this invention, it is preferable to add aluminum sulfate or its hydrate, and another sulfuric acid compound to an aqueous slurry. Other sulfate compounds are not limited, but various gypsums, particularly dihydrate gypsum are preferable. By adding aluminum sulfate or a hydrate thereof and other sulfuric acid compounds, tobermorite formation in the autoclave is accelerated and proceeds uniformly, so that the pores become uniform and contribute to strength development. Even if one of aluminum sulfate or a hydrate thereof and other sulfate compound is used alone, the above effect is exhibited, but when both are used, the above effect is further increased, which is preferable.

The addition amount of aluminum sulfate or its hydrate and other sulfate compounds is not limited, but is preferably 0.09 to 10% by weight in terms of oxide (Al ₂ O ₃ ), based on the total weight of the solid raw material, and others It is preferable that the sulfuric acid compound is mixed with the slurry so as to be 0.15 to 15% by weight with respect to the total weight of the solid raw material in terms of SO ₃ including the aluminum sulfate or its hydrate. If it is less than 0.15% by weight with respect to the total weight of the solid raw material, the effect of improving the strength is not exhibited, and if it exceeds 15% by weight with respect to the total weight of the solid raw material, the viscosity of the slurry is increased. Bubble formation may be inhibited.
The raw material used in the lightweight cellular concrete production method of the present invention preferably has a CaO / SiO ₂ molar ratio of 0.5 to 1.2, more preferably 0.6 to 1.0, and most preferably 0.7. Mix to ~ 0.9. When the CaO / SiO ₂ molar ratio is less than 0.5, a large amount of unreacted silicic acid raw material remains, so the amount of tobermorite produced may be reduced and the strength may not be sufficiently expressed. Not only the amount of tobermorite produced is reduced due to the lack of siliceous components necessary for tobermorite formation, but also the strength may not be sufficiently developed because highly crystalline tobermorite is not produced.

  In the present invention, raw materials other than the above raw materials such as siliceous raw materials, cement, and calcareous raw materials can of course be added as necessary. Examples of these raw materials include, for example, organic lightweight aggregates such as pulp, expanded styrene beads, and organic microballoons, inorganic lightweight aggregates such as pearlite and shirasu balloons, surfactants such as methylcellulose, and thickening agents such as polyacrylic acid and polyvinyl alcohol. Dispersants commonly used in cement materials such as water reducing agents and high performance water reducing agents, carbonate compounds such as calcium carbonate and dolomite, hardening accelerators such as sodium silicate, cement systems such as lignin sulfonic acid and gluconate Curing retarders generally used in materials, foam retarders such as phosphates, water-repellent substances such as siloxane compounds and alkoxysilane compounds, inorganic fibers such as alkali-resistant glass fibers, carbon fibers, stainless fibers, ceramic fibers and asbestos fibers , Aramid fiber, vinylon fiber, polypropylene fiber Organic fibers, etc. and the like.

The silicic raw material, cement, calcareous raw material, and if necessary, the charging method, charging order, and mixing time of the sulfuric acid compound and other raw materials are not limited. For example, as in the prior art, these raw materials may be added simultaneously and mixed for a short time, and a surfactant, metal aluminum powder or slurry thereof may be added and injected into the mold. After mixing, a surfactant, metallic aluminum powder or a slurry thereof may be added and poured into the mold.
In addition, for example, following the first step of mixing siliceous raw material, cement, water, part of calcareous raw material, and if necessary, aluminum sulfate or its hydrate, and other sulfuric acid compounds, it is represented by gypsum. A method of adding a foaming agent such as aluminum powder and injecting it into the mold after the second step of adding the sulfuric acid compound and the remaining calcareous raw material and further mixing can also be used. Even when such a method is used, the method during mixing, the temperature during mixing, and the mixing time are not particularly limited.

If the mixing time of the first step is too short, the uniformity of the raw material slurry tends to decrease, and therefore, it is preferably 10 minutes or more, more preferably 30 minutes or more. If it is too long, hydration of the cement will proceed too much, and the subsequent pre-curing tends to be delayed, so 3 hours or less is preferable. If the temperature during mixing is too low, the subsequent pre-curing tends to be delayed, and if it is too high, the temperature during subsequent foaming and pre-curing is too high, which may cause cracks in the pre-cured body. Therefore, the range of 30-60 degreeC is preferable and the range of 40-55 degreeC is more preferable.
After the completion of the first step, the mixing time and temperature of the second step of adding a sulfuric acid compound typified by gypsum and the remaining calcareous raw material and further mixing are not limited. If the mixing time is too short, uniform dispersion of the raw material slurry cannot be obtained, and if it is too long, subsequent preliminary curing is delayed. Therefore, the mixing time is preferably from 30 seconds to 10 minutes, more preferably from 30 seconds to 3 minutes. The mixing temperature is preferably in the range of 30 to 60 ° C, more preferably in the range of 40 to 55 ° C, for the same reason as in the first step. After the completion of the second step, there is a method in which a surfactant or a surfactant slurry in which a surfactant is dispersed in water, an aluminum powder or an aluminum slurry in which aluminum powder is dispersed in water, and then immediately injected into the mold. Preferably done.

In the method for producing lightweight cellular concrete according to the present invention, it is preferable to form a reinforcing reinforcing bar or reinforcing metal mesh so as to be embedded in the lightweight cellular concrete as in the conventional lightweight cellular concrete. Here, the reinforcing reinforcing bars are those in which reinforcing bars are arranged in a desired shape and the cross contacts are welded. The reinforcing wire mesh is obtained by processing iron into a mesh shape. For example, a lath mesh or the like is a typical example. The shape of the reinforcing bar or reinforcing wire mesh, the size of the reinforcing bar, the size of the reinforcing mesh, the size of the wire mesh, and the position when embeding in lightweight concrete are not limited. It is preferable to select appropriately according to the size, use, and the like.
It is preferable that a rust preventive treatment for imparting durability to these reinforcing steel bars or reinforcing wire mesh is applied. As the rust preventive, known ones such as synthetic resin can be used. In this way, the strength at the time of breakage is remarkably improved by arranging the reinforcing bars or the wire mesh inside.

The slurry injected into the mold is preferably pre-cured at 50 to 85 ° C. over 1 hour or more by foaming, quicklime and self-heating of cement derived from aluminum powder. Pre-curing is preferably performed in an environment where moisture is suppressed from evaporating, such as in a steam curing room. The obtained precured body is cut into an arbitrary shape as necessary, and then cured at high temperature and high pressure using an autoclave. For the cutting, a wire cutting method generally used for manufacturing lightweight cellular concrete can also be used. The conditions of the autoclave are preferably 160 ° C. (gauge pressure: about 5.3 kgf / cm ² ) or more and 220 ° C. (gauge pressure: about 22.6 kgf / cm ² ) or less.

The present invention will be specifically described below with reference to examples.
Various measurement methods used in the present invention are as follows.
[Precured body hardness]
The hardness of the pre-cured body is measured using a Yamanaka type soil hardness meter (No. 351: standard type). On the surface of the cured body, measurement is performed three times at a location 3 cm or more away from each other, and the average value is taken as hardness.
[Bulk specific gravity]
The cured product after autoclaving having the same dimensions as used in the bending test is calculated from the weight and dimensions when dried at 105 ° C. for 24 hours.

[Bending strength, compressive strength]
Measured according to the bending strength and compressive strength measurement of JIS R 5201. That is, the specimen size used for measuring the bending strength is 40 mm × 40 mm × 160 mm, and the span width is 100 mm. As for the compressive strength, the maximum load is measured at a pressure surface of 40 mm × 40 mm in a half sample broken by a bending test. The test sample is dried at 20 ° C. and 60% relative humidity in a constant temperature and humidity chamber when the moisture content on the basis of the 105 ° C. dry condition is 10 ± 2%.

[Calculation of vI, vII and logarithmic quarter value width by mercury intrusion method]
A 2 to 4 mm portion obtained by pulverizing the cured body after autoclaving and classification is dried at 105 ° C. for 24 hours to obtain a measurement sample. The pore size distribution of these samples is measured using a pore sizer 9320 manufactured by Micrometrics. At this time, the contact angle between mercury and the cured product is 130 degrees, and the surface tension of mercury is 484 dyn / cm. From the integrated curve of the pore volume with respect to the measured pore diameter, vI is determined from the integrated value of 0.006 μm to 1 μm, and vII is determined from the integrated value of 10 μm to 400 μm.
Further, two pore diameters giving a height of ¼ of the maximum peak existing in the differential pore distribution obtained by first-order differentiation of the pore volume integrated curve with respect to the measured pore diameters of 0.006 μm to 10 μm. Let A ₁ and A ₂ be the order of the size. The logarithmic ¼ value width is the difference between the common logarithms of A ₁ and A ₂ (refer to the description of FIGS. 1 and 2 above for the calculation of the logarithmic half-value width).

[Water absorption speed]
The size of the test body is 100 mmφ × 100 mm, sealed 1 cm from the bottom so that water does not penetrate from the side, and the bottom is placed on absorbent cotton containing water. At any time, a sample is taken out, the weight is measured, and the water absorption rate is calculated by dividing the amount of absorbed water by the bottom area of the specimen and the square root of the elapsed time.
The drying condition of the test specimen is a constant weight in a constant temperature and humidity chamber of 20 ° C. and a relative humidity of 60%.
[Drying speed]
A test specimen (100 mm × 600 mm × 600 mm) is embedded in water for three days and weighed, then dried under 60 ° C. and 40% RH conditions, and weighed. The water content is defined as the ratio of water contained in the specimen relative to the bulk specific gravity.

[Powder X-ray diffraction]
After the sample used for the strength measurement is pulverized in a mortar, the measurement is performed using a Kα ray of Cu in RINT2000 manufactured by Rigaku Corporation. The measurement conditions are an acceleration voltage of 40 kV, an acceleration current of 200 mA, a light receiving slit width of 0.15 mm, a scanning speed of 4 ° / min, and a sampling of 0.02 °. Diffraction lines are monochromatic by a graphite monochromator and counted.
The tobermorite with respect to the diffraction peak intensity of the (101) plane of quartz, where It is the diffraction peak intensity of the (220) plane of tobermorite including the background, and It is the diffraction peak intensity of the (101) plane of quartz including the background. It / Iq is obtained from the ratio of diffraction peak intensities of the (220) plane.

[Example 1]
To 99.8 parts by weight of water at 50 ° C., 48.1 parts by weight of Chichibu silica stone (manufactured by Chichibu Mining Co., Ltd .: Blaine specific surface area 7500 cm ² / g) as a siliceous raw material, 8.7 parts by weight of quicklime, ordinary portland cement , OPC) 29.1 parts by weight and 1 part by weight of ammonium sulfate (Asahi Chemical Co., Ltd .: 17% product) were added to obtain an aqueous slurry, and the mixture was stirred for 1 hour while maintaining the temperature at 50 ° C. Went. Next, 8.7 parts by weight of quicklime, 4.3 parts by weight of dihydrate gypsum, and 2.217 parts by weight of water in advance are added to water-soluble cellulose ether (Shin-Etsu Chemical Co., Ltd .: hi65SH-4000) 0.0217 weights. The aqueous slurry obtained by partly mixing was added and stirred for 2 minutes.

Subsequently, a metal aluminum slurry in which 0.0854 parts by weight of metal aluminum powder was previously dispersed in 5.4 parts by weight of water was added, stirred for 30 seconds, poured into a mold and foamed, and precured. The slurry temperature at the time of mold injection was 50 ° C.
The center temperature of the pre-cured body after 5 hours from the completion of slurry injection into the mold was 85 ° C., and the hardness reached 10 mm. After removing the formwork, the pre-cured body was put in an autoclave and subjected to autoclave curing at 180 ° C. for 4 hours in a saturated steam atmosphere. After taking out from the autoclave, it was dried to obtain lightweight cellular concrete.
Table 1 shows the properties of the obtained lightweight cellular concrete.
In producing lightweight aerated concrete, the weight ratio of water to the total solid raw material used is 1.08, the ratio of the total calcareous raw material to OPC is 0.6, and the siliceous raw material, cement, and calcareous raw material are CaO. / SiO ₂ molar ratio was mixed at 0.73.

[Example 2]
To 99.8 parts by weight of water at 50 ° C., 46.6 parts by weight of Chichibu silica stone (manufactured by Chichibu Mining Co., Ltd .: Blaine specific surface area 7500 cm ² / g) as a siliceous raw material, 13.7 parts by weight of quicklime, 34.3 parts by weight of OPC, 1 part by weight of sulfate sulfate (manufactured by Asahi Chemical Co., Ltd .: 17% product) and 4.3 parts by weight of dihydrate gypsum in terms of anhydride were added. Furthermore, an aqueous slurry obtained by previously mixing 0.0217 parts by weight of water-soluble cellulose ether (manufactured by Shin-Etsu Chemical Co., Ltd .: hi65SH-4000) in 2.15 parts by weight of water was added and stirred for 2 minutes.

Subsequently, a metal aluminum slurry in which 0.0854 parts by weight of metal aluminum powder was previously dispersed in 5.4 parts by weight of water was added, stirred for 30 seconds, poured into a mold and foamed, and precured. The slurry temperature at the time of mold injection was 50 ° C. The center temperature of the precured body after 5 hours from the completion of slurry injection into the mold was 86 ° C., and the hardness reached 10 mm. After removing the formwork, the pre-cured body was put in an autoclave and subjected to autoclave curing at 180 ° C. for 4 hours in a saturated steam atmosphere. After taking out from the autoclave, it was dried to obtain lightweight cellular concrete.
Table 1 shows the properties of the obtained lightweight cellular concrete.
In producing lightweight aerated concrete, the weight ratio of water to the total solid raw material used is 1.08, the ratio of total calcareous raw material to OPC is 0.4, and siliceous raw material, cement, and calcareous raw material are CaO. / SiO ₂ molar ratio was mixed at 0.73.

[Example 3]
To 99.8 parts by weight of water at 55 ° C., 49.2 parts by weight of Chichibu silica stone (manufactured by Chichibu Mining Co., Ltd .: Blaine specific surface area 7500 cm ² / g) as a siliceous raw material, 20.2 parts by weight of quicklime, 25.3 parts by weight of OPC, 1 part by weight of sulfate sulfate (manufactured by Asahi Chemical Co., Ltd .: 17% product) and 4.3 parts by weight of dihydrate gypsum were added, and water-soluble cellulose ether (Shin-Etsu Chemical Co., Ltd.) was added in advance to 2.15 parts by weight of water. An aqueous slurry obtained by mixing 0.0217 parts by weight of Hi65SH-4000) was added and stirred for 30 minutes.

Subsequently, a metal aluminum slurry in which 0.0863 parts by weight of metal aluminum powder was previously dispersed in 5.4 parts by weight of water was added, stirred for 30 seconds, poured into a mold and foamed, and precured. The slurry temperature at the time of mold injection was 55 ° C. The center temperature of the precured body after 6 hours from the completion of slurry injection into the mold was 79 ° C., and the hardness reached 10 mm. After removing the formwork, the pre-cured body was put in an autoclave and subjected to autoclave curing at 180 ° C. for 4 hours in a saturated steam atmosphere. After taking out from the autoclave, it was dried to obtain lightweight cellular concrete.
Table 1 shows the properties of the obtained lightweight cellular concrete.
In producing lightweight aerated concrete, the weight ratio of water to the total solid raw material used is 1.08, the ratio of total calcareous raw material to OPC is 0.8, and the siliceous raw material, cement, and calcareous raw material are CaO. / SiO ₂ molar ratio was mixed at 0.73.

[Example 4]
To 169.3 parts by weight of water at 60 ° C., 39.2 parts by weight of Chichibu silica stone (manufactured by Chichibu Mining Co., Ltd .: Blaine specific surface area 7500 cm 2 / g) and 9.8 parts by weight of silica fume (manufactured by EFACO), 9 lime .9 parts by weight, 24.8 parts by weight of early strength Portland cement, 2 parts by weight of sulfate sulfate (Asahi Chemical Co., Ltd .: 17% product) in terms of anhydride, and 4.3 parts by weight of dihydrate gypsum were added. An aqueous slurry was obtained and stirred for 1 hour while maintaining the temperature at 60 ° C. Next, 9.9 parts by weight of quicklime is added to the aqueous slurry, and an aqueous slurry obtained by mixing 0.0275 parts by weight of water-soluble cellulose ether (manufactured by Shin-Etsu Chemical Co., Ltd .: hi65SH-4000) in advance to 2.73 parts by weight of water is added. And stirred for 2 minutes.

Subsequently, a metal aluminum slurry in which 0.12 parts by weight of metal aluminum powder was previously dispersed in 9.2 parts by weight of water was added, stirred for 30 seconds, poured into a mold and foamed, and precured. The slurry temperature at the time of mold injection was 60 ° C. The center temperature of the precured body after 6 hours from the completion of slurry injection into the mold was 79 ° C., and the hardness reached 10 mm. After removing the formwork, the pre-cured body was put in an autoclave and subjected to autoclave curing at 180 ° C. for 4 hours in a saturated steam atmosphere. After taking out from the autoclave, it was dried to obtain lightweight cellular concrete. The time when the moisture content reached 20% was 9 days.
In producing lightweight aerated concrete, the weight ratio of water to the total solid raw material used is 1.83, the ratio of total calcareous raw material to OPC is 0.8, and the siliceous raw material, cement, and calcareous raw material are CaO. / SiO ₂ molar ratio was mixed at 0.73.

[Comparative Example 1]
Molding was performed in the same manner as in Example 1 except that the water-soluble cellulose ether as a surfactant was not added. The center temperature of the precured body after 5 hours from the completion of the slurry injection into the mold was 85 ° C., the hardness reached 10 mm, and the mold was removed.
Table 2 shows the properties of the obtained lightweight cellular concrete.

[Comparative Example 2]
Water at 50 ° C. is 89 parts by weight, and an aqueous slurry of water-soluble cellulose ether as a surfactant is preliminarily prepared by adding water-soluble cellulose ether (manufactured by Shin-Etsu Chemical Co., Ltd .: hi65SH-4000) to 12.9 parts by weight of water. An aqueous slurry obtained by mixing 13 parts by weight, and was molded in the same manner as in Example 1 except that 0.12% by weight of the surfactant was contained with respect to the amount of water in the slurry containing the foaming agent. It was. The center temperature of the pre-cured body after 8 hours from completion of slurry injection into the mold was 86 ° C., the hardness reached 10 mm, and the mold was removed.
Table 2 shows the properties of the obtained lightweight cellular concrete. Many small cracks were observed on the fracture surface after the bending strength measurement.

[Comparative Example 3]
To 99.8 parts by weight of water at 50 ° C., 50.5 parts by weight of Chichibu silica stone (manufactured by Chichibu Mining Co., Ltd .: Blaine specific surface area 7500 cm ² / g), 11.7 parts by weight of quicklime, 20.8 parts by weight of OPC, And 1 part by weight of an ammonium sulfate (Asahi Chemical Co., Ltd. product: 17% product) was added to obtain an aqueous slurry, and the mixture was stirred for 1 hour while maintaining the temperature at 50 ° C. Next, 1.15 parts by weight of quick lime and 4.3 parts by weight of dihydrate gypsum were added to the aqueous slurry, and 2.15 parts by weight of water was previously added to the slurry in which the ratio of the calcareous raw material to cement was 1.13 by weight. An aqueous slurry obtained by mixing 0.0217 parts by weight of water-soluble cellulose ether (manufactured by Shin-Etsu Chemical Co., Ltd .: hi65SH-4000) was added to and stirred for 2 minutes.

Subsequently, a metal aluminum slurry in which 0.0836 parts by weight of metal aluminum powder was previously dispersed in 5.4 parts by weight of water was added, stirred for 30 seconds, poured into a mold and foamed, and precured. The slurry temperature at the time of mold injection was 50 ° C. The center temperature of the pre-cured body after 6 hours from the completion of slurry injection into the mold was 86 ° C., and the hardness reached 10 mm. After removing the formwork, the pre-cured body was put in an autoclave and subjected to autoclave curing at 180 ° C. for 4 hours in a saturated steam atmosphere. After taking out from the autoclave, it was dried to obtain lightweight cellular concrete.
Table 2 shows the properties of the obtained lightweight cellular concrete.
In producing lightweight aerated concrete, the weight ratio of water to the total solid raw material used is 1.08, the ratio of total calcareous raw material to OPC is 1.13, and the siliceous raw material, cement, and calcareous raw material are CaO. / SiO ₂ molar ratio was mixed at 0.73.

[Comparative Example 4]
To 99.8 parts by weight of water at 50 ° C., 44.5 parts by weight of Chichibu silica stone (manufactured by Chichibu Mining Co., Ltd .: Blaine specific surface area 7500 cm ² / g), 8.4 parts by weight of quicklime, 41.8 parts by weight of OPC, The ratio of calcareous raw material to cement, with 1 part by weight of sulfate sulfate (Asahi Chemical Co., Ltd .: 17% product) and 4.3 parts by weight of dihydrate gypsum added, is 0.2 by weight. An aqueous slurry was obtained, and an aqueous slurry obtained by mixing 0.0217 parts by weight of water-soluble cellulose ether (manufactured by Shin-Etsu Chemical Co., Ltd .: hi65SH-4000) in advance with 2.15 parts by weight of water was added and stirred for 2 minutes.

Subsequently, a metal aluminum slurry in which 0.0863 parts by weight of metal aluminum powder was previously dispersed in 5.4 parts by weight of water was added, stirred for 30 seconds, poured into a mold and foamed, and precured. The slurry temperature at the time of mold injection was 50 ° C. The center temperature of the precured body after 5 hours from the completion of slurry injection into the mold was 78 ° C., and the hardness reached 10 mm. After removing the formwork, the pre-cured body was put in an autoclave and subjected to autoclave curing at 180 ° C. for 4 hours in a saturated steam atmosphere. After taking out from the autoclave, it was dried to obtain lightweight cellular concrete.
Table 2 shows the properties of the obtained lightweight cellular concrete.
In producing lightweight aerated concrete, the weight ratio of water to the total solid raw material used is 1.08, the ratio of the total calcareous raw material to OPC is 0.2, and the siliceous raw material, cement, and calcareous raw material are CaO. / SiO ₂ molar ratio was mixed at 0.73.

  INDUSTRIAL APPLICABILITY The present invention is particularly lightweight and has a necessary strength as a building material, and has high followability to changes in the surrounding environment, so that it can provide a building material with excellent long-term weather resistance, fire resistance, and indestructibility. . Therefore, it is suitable as an outer wall material, a floor material, and an inner wall material of a building that realizes weight reduction of the building, and realizes improvement of safety during field work and reduction of burden on workers.

It is a distribution map which shows the calculation method of the differential pore distribution whose pore diameter of the lightweight cellular concrete measured by the mercury intrusion method is 0.006 micrometer-1 micrometer, and logarithm 1/4 width. Distribution showing the method for calculating the logarithmic quarter width when the pore diameter is in the range of 0.006 μm to 1 μm and there are more than two pore diameters giving a height of ¼ of the maximum value in the differential pore distribution curve. FIG.

Claims (10)

It consists mainly of tobermorite, has a bulk specific gravity of 0.2 or more and less than 0.45, and among pores measured by the mercury intrusion method, the cumulative pore volume vI in the range of 0.006 μm to 1 μm is 0. 7cm ³ /g~2.5cm ³ / g, and the and the pore diameter measured by mercury porosimetry is cumulative pore volume vII ranging 10μm~400μm 0.09cm ³ /g~1.0cm ³ / A lightweight cellular concrete characterized by being g. The cumulative pore volume vI having a pore diameter in the range of 0.006 μm to 1 μm is greater than or equal to f ₁ (d) cm ³ / g expressed by Equation (1) and Equation (2) based on the bulk specific gravity (d), and f _2. The lightweight cellular concrete according to claim 1, which is ₂ (d) cm ³ / g or less.
f ₁ (d) = 0.15 / d + 0.37 (1)
f ₂ (d) = 0.15 / d + 1.75 (2)   The differential pore distribution curve measured by the mercury intrusion method has at least one maximum value in the pore diameter range of 10 to 400 μm, and the pore diameter that gives the maximum value is in the range of 40 to 200 μm. The lightweight cellular concrete according to claim 1 or 2.   Among the pores measured by the mercury intrusion method, the logarithmic distribution width at the height of 1/4 of the maximum value of the differential pore distribution curve in the pore diameter range of 0.006 μm to 1 μm is 0.4 to 1.4. The lightweight aerated concrete according to any one of claims 1 to 3, wherein the lightweight aerated concrete is.   The lightweight cellular concrete according to any one of claims 1 to 4, wherein the bulk specific gravity is 0.23 or more and 0.4 or less.   Aqueous slurry containing at least siliceous raw material, cement and calcareous raw material is mixed with metal aluminum powder as a foaming agent, poured into a mold, precured, and then autoclaved, and has a bulk specific gravity of 0.2 to less than 0.45. In the method for producing cellular concrete, the ratio of the calcareous raw material to the cement is 0.3 to 1.0 by weight, and the slurry containing the cellular agent is a surfactant with respect to the amount of water in the slurry. 0.001 to 0.1% by weight of a lightweight cellular concrete manufacturing method characterized by the above-mentioned.   The method for producing lightweight aerated concrete according to claim 6, wherein the weight ratio of water to the total solid raw material in the slurry before being poured into the mold is 0.78 or more and 2.66 or less. As siliceous raw material, manufacturing method of lightweight concrete according to claim 6 or 7, wherein the Blaine specific surface area is characterized by using a crystalline siliceous material the 5000~15000cm ² / g.   The method for producing lightweight aerated concrete according to any one of claims 6 to 8, wherein aluminum sulfate or a hydrate thereof and other sulfate compound are added to the aqueous slurry. Siliceous material, cement and calcareous material is lightweight concrete according to any one of claims 6-9, characterized in that it is mixed with 0.5 to 1.0 at CaO / SiO ₂ molar ratio Manufacturing method.

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