JP2000072515A - Hardened cement product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hardened cement product that can be produced at a low cost without adverse effect on quick hardening, even when a hardening inhibitor is included by using a cement that can attain the harmony with environment based on the neutral resource recycle. SOLUTION: This is a hydraulic composition that includes at least one of fired products selected from the group consisting of municipal waste incineration ashes and sewage sludge incineration ashes and contains 10-40 wt.% of C11 A7CaCl2 and further contains at least one of fired product selected from the group consisting of C2S and C3S and plaster. This hydraulic composition, a filler, water, and at least one slaking substance selected from fired calcia or magnesia are formed and cured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hardened cement material, and more particularly, to incinerated ash from municipal waste.
Cement hardening mainly for building material applications, using low-cost and rapid productivity based on environment-friendly cement based on resource recycling using one or more types of sewage sludge incineration ash as a cement raw material It is about things.

[0002]

2. Description of the Related Art There are a wide variety of inorganic building interior and exterior materials in the context of the sophistication and diversification of buildings. Among them, cement-based board materials using cement as a main constituent material Is widely used as an inexpensive building material with excellent durability and fire resistance regardless of the interior or exterior.

[0003] In particular, wood chips, pulp, and cement boards using various reinforcing fibers and lightweight aggregates as filler materials are well known, and are used as building materials in wood wool cement boards, ceramic siding materials, roofing materials, and the like. Now we have a solid position. Among these, ceramic siding materials are superior to mortar-based exterior wall materials, etc., which have been widely used in the past, because they have excellent workability and fire resistance, and they have the flexibility to respond to various designs. It is one of the things that is rapidly increasing its demand.

The ceramic siding material is, as described above, a composite material obtained by mixing wood chips, pulp, reinforcing fibers, lightweight aggregates, etc. with cement. Generally, these raw materials are slurried or wet. After being mixed in the state, it is formed into a sheet material by a molding method such as a pressing method, an extrusion molding method, or a papermaking method. By the way, these molding methods are basically batch processes, and there is a problem that productivity is inferior as a method for producing a large amount of building materials. For these reasons, various efforts have been made to improve the molding method and to develop new processes for the purpose of improving productivity.

[0005] For example, the "cemented excelsior manufacturing method" of _{JP-A-58-204855, C 11 A 7 X 2} , C
₃ A ₃ CAX ₂ (X represents a halogen atom), C ₃ A ₃
CaSO _4, C ₁₂ A at least one compound selected from ₇ plus wood wool or the like ultrarapid hardening cement plus calcium sulfate, a technique for pressure compression have been proposed. According to this method, the setting time of the cement is dramatically reduced,
It is considered that productivity can be greatly improved because the time required for pressurization and compression can be greatly reduced.

However, the C ₁₁ A used here
₇ X ₂ , C ₃ A ₃ CAX ₂ , C ₃ A ₃ CaSO ₄ , C
Calcium aluminate minerals such as ₁₂ A ₇ is quite different from the mineral composition of the ordinary Portland cement, which must be prepared in particular under formulation for this purpose, compared with ordinary Portland cement It is undeniable that the cost will be overwhelmingly high.

Therefore, the present inventors utilized municipal refuse incineration ash or sewage sludge incineration ash to convert C ₁₁ A ₇ CaCl ₂ to 10 to 10%.
A technique was proposed in which a hydraulic composition containing 40% by weight, containing at least one selected from C ₂ S and C ₃ S, and further containing gypsum was cured to obtain a hardened cement product. Since the hydraulic composition uses waste and has an extremely fast curing property, there is a strong expectation for a reduction in the cost of producing a cured cement product.

[0008]

However, in general, there is a problem that the curing reaction of cement is liable to be inhibited by a filler material, for example, lignin or tannin contained in wood. That is, as described above, wood fillers such as wood chips and wood fibers are often added to cement-based building boards for weight reduction, reinforcement, or improvement in workability. Lignin and tannin contained therein are eluted in water during preparation of the cement slurry, and tend to delay the hardening reaction of the cement. When rapid curability is required, it is presently an unavoidable problem that the production cost increases due to the presence of these curing inhibitors. Therefore, an object of the present invention is to use an environment-friendly cement based on resource recycling using at least one of municipal garbage incineration ash and sewage sludge incineration ash as a cement raw material. It is an object of the present invention to provide a hardened cement material which can be manufactured at low cost without being adversely affected by heat.

[0009]

As a result of intensive studies, the present inventors have been able to solve the above-mentioned conventional problems. That is, the present invention provides a cured cement product obtained by molding and curing a slurry composition containing the following various components. Ingredients contained in the slurry composition: A hydraulic composition containing at least one calcined product selected from the group consisting of municipal garbage incineration ash and sewage sludge incineration ash, wherein C ₁₁ A ₇ CaCl ₂ is 10 to 40% by weight. % Included
And a hydraulic composition comprising a calcined product containing one or more selected from the group consisting of C ₂ S and C ₃ S and gypsum; a filler material; water; and a calcined material selected from the group consisting of calcia, magnesia and calcined dolomite. One or more digestive substances. Further, the present invention provides the above-described cured cement product, wherein the slurry composition further contains various additives (materials). Further, the present invention provides a method for treating a digestive substance having a total digestion reaction time of A
In a method for measuring a digestion rate specified in STM C 110-76a, the present invention provides the above-mentioned hardened cement material having the following ranges. Calcia: within 20 minutes Magnesia: within 10 minutes Dolomite calcined: within 20 minutes Still further, the present invention provides the above-described hardened cement, wherein the filler material and / or the additive (material) contains a component that inhibits a hardening reaction of the cement.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION (Hydraulic composition) The hydraulic composition is a hydraulic composition containing one or more calcined products selected from the group consisting of municipal waste incineration ash and sewage sludge incineration ash, 10 to 40% by weight of C ₁₁ A ₇ CaCl ₂ ,
And a calcined product containing at least one selected from the group consisting of C ₂ S and C ₃ S and gypsum. These may be prepared for this purpose, or for example, an environment-friendly hydraulic composition disclosed in JP-A-7-165446, or a quick-setting mixed cement disclosed in JP-A-7-165449, for example, Alternatively, cement (eco-cement) utilizing living and industrial wastes disclosed in Japanese Patent Application No. 8-64486 can be used. In particular, eco-cement is, specifically, a burned material such as municipal ash, sewage sludge incineration ash, and the like, which is preferable from the viewpoint of reducing the cost of the cement itself and effective use of resources.

The form of gypsum used in the hydraulic composition is as follows:
There is no particular limitation, and gypsum dihydrate, α-type / β-type hemihydrate gypsum, type-III anhydrous gypsum, type-II anhydrous gypsum and the like can be used alone or in combination. The amount of the gypsum is not particularly limited, but the molar ratio is preferably 0.4 to 3.0, preferably 0.5 to 2.0 with respect to Al ₂ O ₃ in the hydraulic composition. . Depending on the cement raw material, gypsum may coexist in the hydraulic composition, but in this case, the molar ratio of SO ₃ / Al ₂ O ₃ is selected.

The above-mentioned hydraulic composition is used as a part or all of a cement raw material, and when it is used as a part, it is usually made of portland cement, high-strength cement, highly basic calcium chlorosilicate (eg, alinite, berynite), calcium Fluoroaluminate (C ₁₁ A ₇ CaF ₂ ),
Irwin (C ₃ A ₃ CaSO ₄ ) or a mixture with other cement is used. In this case, the mixing ratio of the hydraulic composition is preferably at least 30% by weight or more, and more preferably 50% by weight or more. When the content is 30% by weight or more, the characteristics of the hydraulic composition described above are sufficiently exhibited.

The hydraulic composition has a setting time according to JIS R 5201 of about 10 to 40 minutes at the start and about 30 to 60 minutes at the end. On the other hand, the starting time of ordinary Portland cement is about 120 to 200 minutes, and the ending time is about 240 to 360 minutes. In the case of ultra-fast-hardening cement represented by jet cement, the starting time is about 5 minutes.
~ 20 minutes, with a termination time of about 20-40 minutes. As described above, the setting time of the hydraulic composition of the present invention is overwhelmingly short for ordinary Portland cement, and is almost equal to or slightly slower than jet cement.

[0014] The jet cement is a cement containing calcium fluoroaluminate, and is a special cement which is frequently used in various civil engineering construction works and the like due to its super-rapid hardening property.

(Filler material) The filler material is compounded for the purpose of reinforcing, imparting workability, reducing weight, increasing the amount, and the like. Examples include wood fillers such as wood chips and wood fibers, pulp fibers, other inorganic and organic reinforcing fibers,
Inorganic and organic lightweight aggregates, crushed stones, fine and coarse aggregates and the like can be mentioned. The type and amount of the filler material may be determined according to the performance of the target product.

(Water) The mixing amount of water is appropriately determined in consideration of the specific gravity, desired strength and the like of the obtained cement hardened product.
For example, the water / cement ratio is about 20 to 150%.

(Digestible substance) In the present invention, one or more digestible substances selected from the group consisting of calcia, magnesia and calcined dolomite are used. These are accompanied by an exotherm generally called digestive fever in the reaction with water, ie, the digestive reaction. In the present invention, this heat generation is used to avoid adverse effects of the curing inhibitor. The temperature dependence of the hydration reaction of calcium chloroaluminate (C ₁₁ A ₇ CaCl ₂ ) contained in the hardened cement of the present invention is extremely high, and the adverse effects of the hardening inhibitor can be prevented beforehand. Unless a digestible substance has a certain digestion rate, it does not generate digestive heat enough to promote curing. Therefore, digestive substances have a total digestion reaction time of AST
In the method of measuring the digestion rate specified in MC110-76a, it is desirable that the digestion rate is in the following range. That is: Calcia: within 20 minutes Magnesia: within 10 minutes Dolomite calcined: within 20 minutes. Furthermore, in the present invention, the shorter the total digestion reaction time of the digestible substance, the less likely it is to be affected by the curing inhibitor, so when using a filler material or admixture whose curing time is greatly delayed, calcia And less than 10 minutes for magnesia and less than 10 minutes for calcined dolomite. ASTM C 110-76a includes:
Although the method for measuring magnesia and calcined dolomite is not clearly described, these shall be measured according to the method for measuring calcia. The specific digestion rate of the digestible substance can be appropriately selected according to the performance of the target product and the production process. In addition, digestible substances have different digestion rates depending on the production method, and various substances are commercially available. Suitable digestion rates are, for example,
Press molding (continuous, semi-continuous, batch type) from the casting of the mold to the demolding in the case of known mold casting and from the casting to the cutting of the molded body in the case of continuous casting.
If so, it is desirable that the digestion reaction is completed from the release of pressure to the handling. In the present invention, the amount of the digestible substance may be appropriately selected, and is, for example, 1 to 10% by weight based on the hydraulic composition.

The curing inhibitor is often contained in filler materials and admixtures (materials), for example, inorganic substances such as phosphates, silicon fluorides, borates and zinc compounds; sugars (galactose, fructose, glucose) Monosaccharides, sucrose, disaccharides such as lactose, dextrins, polysaccharides such as glycogen), high-molecular organic acids (lignin, tannic acid, humic acid, etc.), carboxylic acids (glycolic acid, tartaric acid, citric acid,
Organic substances such as malic acid, succinic acid, formic acid, acetic acid, lactic acid, oxalic acid, etc., alcohols (glycerin, ethyl alcohol, isobutyl alcohol, etc.), and the like. The invention is effective. That is, rapid curability is not impaired.

(Various Additives (Materials)) The slurry composition of the present invention may contain various additives (materials) in addition to the above. Examples thereof include a setting accelerator, a slurry fluidizer, various dispersants, a foaming agent (material), and a thickener. The types and amounts of these are adjusted according to the handling of the slurry composition on the production line and the performance of the target product.

In the present invention, the molding process includes known mold casting, continuous casting, press molding (continuous,
Semi-continuous, batch type) or the like can be appropriately selected. In the curing step, a method known in the art such as wet curing, steam curing, heated curing, pressurized curing, and autoclave curing (high temperature / high pressure, low temperature / low pressure) can be used.

The present inventors consider as follows why the curing inhibitor is not adversely affected even if it is present. The hardening inhibitor fixes the calcium component contained in the cement and inhibits the reaction of forming ettringite for expressing the initial strength. On the other hand, the development of the initial strength in the hydraulic composition used in the present invention is presumed to be due to the formation of Friedel's salt, which is very similar to ettringite, in addition to ettringite. It is considered that Friedel's salt is relatively easy to produce even in an environment with a low calcium concentration, so that it is possible to secure a certain initial strength. As described above, the hydraulic composition follows a unique hydration process as compared with other cement minerals. Found that it had a very high temperature dependence compared to other cement minerals. That is, the higher the reaction temperature, the faster the curing reaction can take place before it is adversely affected by the curing inhibitor. The high temperature of the reaction system is supplied by the heat of digestion of the digestive substance. Achieving rapid hardening allows for quick demolding of hardened cementitious products manufactured, for example, by cast-molding of molds, leading to significant cost reductions due to improved productivity, faster mold rotation, etc. it can. In addition, the production speed of various types of cement hardened products produced by continuous casting or press molding can be increased, and as a result, significant cost reduction can be expected.

[0022]

Next, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Next, various materials used in the examples will be described. A city hydraulic composition comprising one or more of the burned material selected from the group consisting of waste incineration ash and sewage sludge incineration ash _includes C ₁₁ A 7 CaCl ₂ 10~40 wt%, and _{C 2} S and Eco-cement manufactured by Chichibu Onoda Co., Ltd. was used as a hydraulic composition containing a calcined product containing at least one selected from the group consisting of C ₃ S and gypsum. This eco-cement is manufactured using municipal garbage incineration ash. C ₁₁ A ₇ CaCl ₂ is 24% by weight, and C ₂ S is 15%.
% By weight, and 15% by weight of C ₃ S. Next, Ecocement 1
A basic compound was prepared by adding 50 parts by weight of kneading water, 7 parts by weight of a digestible substance, or 7 parts by weight of slaked lime instead of the digestible substance to 00 parts by weight. Further, as shown in Table 1 below, 5 parts by weight of Yonematsu syrup was added to the basic formulation as a filler material, and an aqueous extract of Yonematsu syrup was used as an admixture (weight ratio of Yonematsu / water = 1/3, extracted for 1 day) ) (Replaced by kneading water) and 0.1 part by weight of dextrin from Japan Cornstarch as an admixture, and mixed for 1 minute using a Henschel mixer (20 liters of kneaded product) manufactured by Mitsui Mining Co., Ltd. 50 × 50 × 2c of the obtained slurry composition
m and cast into a mold to obtain a cured cement product.

As the evaluation of the cement hardened material, the possibility of demolding, the possibility of inversion, and the possibility of cutting were examined. Whether the removal is possible
The cast slurry composition was allowed to stand at room temperature for 10 minutes, and then, when the mold was removed, the composition was peeled off without adhering to the mold and a cured product was formed.
Those in which the composition adhered to the mold were evaluated as unacceptable. The possibility of reversal is further increased by 20 for only the cured product that has been released from the mold.
The cured product is allowed to stand at room temperature for 20 minutes.
cm on a reversible horizontal slit (support rod width 5 cm, four at regular intervals), and move the horizontal slit to 1 / 2π
The cured product was evaluated as acceptable if it was inverted without breaking even when it was inverted at rad / sec, and unacceptable if it was broken. The cutability is determined by leaving the cured product alone at room temperature for another 40 minutes, cutting it with a tip saw (saw blade moving speed 5 cm / sec), and cutting it with no squares. Was evaluated as unacceptable. Table 1 also shows the obtained results. The total digestion reaction time of digestible substances was measured according to the digestion rate measurement method specified in ASTM C110-76a.

[0024]

[Table 1]

In Test Examples 1 to 24 of the present invention, demolding was possible in spite of the presence of the curing reaction inhibiting substance. In particular, calcia with a total digestion reaction time of less than 20 minutes,
It was confirmed that the system containing magnesia within 10 minutes and dolomite calcined material within 20 minutes had excellent results in all evaluation items. On the other hand, it can be seen that the systems in which slaked lime of Test Examples 25 to 27 were mixed resulted in poor results. As in the above-described embodiment, the present invention provides a desired rapid curing property even when a vegetable or organic curing inhibitor such as a wood filler (wood fiber, wood wool, wood chip) is contained in the formulation. Can be secured.

[0026]

According to the present invention, an environment-friendly cement based on resource recycling using at least one of municipal waste incineration ash and sewage sludge incineration ash as a cement raw material is used. Provided is a hardened cement which can be manufactured at low cost without being adversely affected by rapid hardening.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C04B 24:38 18:26) 103: 12 103: 30 103: 44 111: 20 (72) Inventor Norifumi Nagata F-term (reference) 4G012 PB03 PD01 in Building Materials Techno Research Laboratory, Inc. 2-4-2 Daisaku, Sakura City, Chiba Prefecture

Claims (4)

[Claims] 1. A hardened cementitious product obtained by molding and curing a slurry composition comprising the following various components. Ingredients contained in the slurry composition: A hydraulic composition containing at least one calcined product selected from the group consisting of municipal garbage incineration ash and sewage sludge incineration ash, wherein C ₁₁ A ₇ CaCl ₂ is 10 to 40% by weight. % Included
And a hydraulic composition comprising a calcined product containing one or more selected from the group consisting of C ₂ S and C ₃ S and gypsum; a filler material; water; and a calcined material selected from the group consisting of calcia, magnesia and calcined dolomite. One or more digestive substances. 2. The hardened cement according to claim 1, wherein the slurry composition further contains various additives (materials). 3. The total digestion reaction time of digestible substances is ASTM.
The method for measuring a digestion rate specified in C110-76a, wherein each of the ranges is as follows.
The cured cement according to the above item. Calcia: within 20 minutes Magnesia: within 10 minutes Dolomite calcined: within 20 minutes 4. Filler material and / or additive (material)
Contains a component that inhibits the hardening reaction of cement.
4. The hardened cement according to any one of items 3 to 3.