JP2002274927A - Hardenable composition and hardened body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hardened body which does not cause crazing even under the dry environment and has excellent acid resistance and durability, and to provide a hardenable composition which is low in the adhesiveness to implements and is good in workability when fresh mortar and concrete are formed. SOLUTION: The hardenable composition formed by incorporating (E) alcohols of 1 to 30 pts.wt. per 100 pts.wt. solid content of (C) water glass into a composition containing the following components; (A) 5 to 70 wt.% alumina cement, (B) 2 to 40 wt.% molten slag powder of >=1.2 in the molar ratio of CaO/SiO2 , (C) 5 to 40 wt.% water glass in terms of solid content and (D) 5 to 60 wt.% molten slag powder (D-1) of 0.10 to 1.20 in the molar ratio of CaO/ SiO2 and/or SiO2 -Al2 O3 reactive powder (D-2) and the hardened body thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition utilizing molten slag such as sewage and municipal waste and having excellent acid resistance and durability, and a cured product thereof.

[0002]

2. Description of the Related Art Incinerated ash and fly ash of sewage sludge and general garbage contain a large amount of heavy metals, and therefore cannot be directly discarded in consideration of environmental pollution. Conventionally, after fixing heavy metals, It was used for roadbed materials and landfills, solidified with cement and disposed of. In recent years, waste molten slag and the like have been effectively reused as admixtures for mortar or concrete or as raw materials for mixed cement.

[0003] The purpose of blending molten slag and the like into a cement raw material is mainly to impart chemical resistance such as chemical resistance, sulfuric acid resistance and seawater resistance, but even when such cement is used. Mortar and concrete are not necessarily resistant to acids, and usually require surface treatment to impart corrosion resistance to acids. For example, the concrete surface of a concrete sewage treatment tank or the like is easily eroded, and may be eroded as the reinforcing steel inside the concrete is exposed. The cause is that sulfate ions and organic matter in the liquid phase part of the sewage produce hydrogen sulfide by sulfate reducing bacteria in an oxygen-free environment,
This is because it diffuses into the gas phase, and then sulfuric acid, which is a corrosive liquid, is generated by the sulfur-oxidizing bacteria in the gas phase, and the sulfuric acid erodes the concrete. For this reason, a resin coating is applied to the surface to prevent acid attack on the concrete layer.

[0004] Water glass concrete containing water glass has been used in view of imparting acid resistance to the concrete layer itself. Such water-glass concrete hardens by using acid-resistant silica gel by using sodium silicofluoride, aluminum phosphate or the like as a hardener.

[0005] However, the surface treatment for imparting corrosion resistance to concrete is performed when the surface is slightly defective.
From there, the acid eroded and corrosion started, so it was difficult to achieve a complete anticorrosion method. Water glass concrete, which imparts acid resistance to the concrete layer itself, is excellent in acid resistance, but has disadvantages of shrinkage due to dehydration and poor water resistance. In order to improve such disadvantages, a sulfuric acid-resistant curable composition containing water glass and amorphous molten slag has been devised (WO97 / 07072, JP-A-10-218644). Reduction of shrinkage of the cured body is not enough, and when plastering mortar is made using this, remarkable cracks often occur after construction, especially when the construction is used or used in a severe dry environment. It was a problem. Further, such a curable composition has a very strong adhesion to metal, and fresh mortar adheres to a conventional metal application tool. There is also a problem that it is necessary to deal with the problem by using a plastic tool having poor performance.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a curable composition mainly composed of molten slag and water glass, which has acid resistance and excellent workability, and can be used in a severely dry environment. Another object of the present invention is to provide a composition having a low degree of shrinkage of a cured product and a low risk of causing cracks.

[0007]

Means for Solving the Problems The present inventors have found that, in a curable composition mainly composed of water glass and molten slag, cracks in a cured body in a dry environment are caused by shrinkage and curing due to the formation of silica gel during curing. Considering that shrinkage due to subsequent dehydration occurs continuously, the component composition was further examined, and it was found that the shrinkage of the cured product could be significantly reduced by adding a certain amount of alcohols, and the present invention was completed. .

That is, the present invention provides the following components (A) to
(D): (A) alumina cement 5 to 70% by weight,
(B) 2 to 40% by weight of molten slag powder having a CaO / SiO ₂ molar ratio of 1.20 or more, (C) 5 to 40% by weight in solid content of water glass, and (D) a molar ratio of CaO / SiO _2. 0.10 to 1.20 molten slag powder (D-1) and / or
Or SiO ₂ -Al ₂ O ₃ reactive powder (D-2) 5~6
A curable composition containing (C) 1 to 30 parts by weight of alcohol (E) per 100 parts by weight of solid content of water glass, a composition containing 0% by weight, and water and a curable composition. And a cured product obtained by curing.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The cured product composition of the present invention is obtained by adding (E) an alcohol to the curable composition of the above components (A) to (D). (F) to (I) can be contained. Hereinafter, each component will be described.

As the alumina cement (A), there is no particular limitation, and a commercially available one can be used. Preferably, the one having a high CaO.Al ₂ O ₃ content is preferable. For example, "Sekar 51BTF" (manufactured by Lafarge),
"Alumina cement No. 1" (manufactured by Denki Kagaku Kogyo Co., Ltd.) is a preferred example. The content of the component (A) is in the range of 5 to 70% by weight. If it exceeds 70% by weight, good acid resistance is not exhibited, and if it is less than 5% by weight, the amount of shrinkage of the cured product tends to increase particularly during curing at room temperature.

(B) CaO / SiO_TwoIs 1.2.
Zero or more molten slag powders include CaO and SiO_Two
To CaO / SiO_TwoAmorphous containing at a molar ratio of 1.2 or more
Is not particularly limited as long as it is natural, artificial, or industrial by-product.
Can be used from any material or waste.
Blast furnace slag, which is a typical industrial by-product, is also preferred.
The fineness is 4000 cm in specific surface area.^Two/ g or more
Is preferred. In the present invention, such a component (B) and
CaO / SiO of component (D) described later _TwoMolten slag powder
(D-1) and / or SiO_Two-Al_TwoO_ThreeReactive powder
(D-2) is used in combination, but this allows room temperature
A cured product having good strength development in green can be obtained.
Early strength is obtained by increasing the content of component (B).
However, the acid resistance tends to decrease at the same time. For this reason
Total CaO / SiO of component (B) and component (D) _TwoMolar ratio
In consideration of the above, the content of the component (B) is determined. component
Total of CaO / SiO of (B) and component (D)_TwoThe molar ratio is
From the viewpoint of acid resistance, it is preferably 1.20 or less, more preferably
It is preferably 0.80 or less, particularly preferably 0.60 or less. this
Therefore, CaO and SiO in the composition of the component (D) used
_TwoThe proper content of component (B) depends on the content of
However, as for the range of the content, the strength required for the cured product is confirmed.
Content to maintain the minimum content to maintain good acid resistance.
The upper limit of the amount is in the range of 2 to 40% by weight.

As the water glass (C), commercially available water glass can be used.
In addition to the items No. 3 and No. 3, non-JIS products manufactured and sold by each water glass maker can also be used. These may be used alone or in combination of two or more.

Among the component (D), the molten slag powder having a CaO / SiO ₂ molar ratio of 0.10 to 1.20 shown in (D-1) contains CaO and SiO ₂ ,
It is not particularly limited as long as it is amorphous having an aO / SiO ₂ molar ratio of 0.10 to 1.2, and any one derived from natural, artificial, industrial by-products or waste can be used. For example, there are waste melting slags such as sewage sludge melting slag and municipal waste melting slag, but it is economical to use sewage sludge melting slag or municipal waste melting slag, and social The significance is significant. These molten slags may be used in combination of two or more as appropriate. These do not need to be manufactured by firing.

CaO / SiO ₂ in component (D-1)
Is 0.10 to 1.20, but 0.10 to 0.10.
0.90 is preferable, and 0.10 to 0.60 is particularly preferable. If it is less than 0.10, the reactivity is low, sufficient initial strength is not exhibited, and a durable cured product cannot be obtained. On the other hand, 1.
If it is higher than 20, calcium hydroxide remains and reacts with sulfuric acid to form gypsum and causes expansion failure, so that good acid resistance cannot be secured.

The molten slag powder of the component (D-1) has a fineness of specific surface area of 2,000 to 15,000 cm.
² / g, preferably 3000-15000 cm ² / g, especially 40
Those having a range of 00 to 15000 cm ² / g are preferred from the viewpoint of the strength development of the cured product. The specific surface area is 15000.
Although those exceeding cm ² / g can be suitably used, those having a particle size of 15000 cm ² / g or less are preferred from the viewpoint of pulverization cost.

Among the component (D), the SiO ₂ —Al ₂ O ₃ reactive powder represented by (D-2) includes, for example, SiO ₂ and Al ₂ O capable of eluting Al ions under alkali stimulation.
Powders derived from natural, artificial, industrial by-products and wastes containing ₃ can be used. Specifically, kaolinite, a natural clay mineral, is heated, its bound water is removed, and metakaolin or an intermediate thereof in which most of the structure has been made amorphous can be used, and commercially available ones are also suitable. Can be used. Fineness of the reactive powder has a specific surface area of 4000 cm ² / g or more, preferably 6000 cm ² / g or more, further 8000 cm ² / g or more.

[0017] By blending the component (D-2), drying shrinkage of the cured product can be further reduced, and cracks can be prevented. That is, the drying shrinkage of the product in the process of producing the effector is caused by dehydration of the silica gel, but the component (D-
By blending 2), a part of the silicate gel becomes an aluminosilicate having a smaller shrinkage, and the shrinkage is suppressed. Accordingly, as the component (D-2), those having a large elution amount of Al ions in the reaction under alkali stimulation are preferable, and those having an amorphous crystal structure are preferable because of high reactivity.

Component (D) ((D-1) and / or (D-
The range of the content of 2)) is determined by the mixing amount with the above-mentioned component (B), but the range is 5 to 60% by weight in consideration of acid resistance and strength development required for the cured product. It is.

As the alcohols (E), commercially available liquid alcohols such as methanol and ethanol, and powdered or granular alcohols such as polyvinyl alcohol can be used, and the type thereof is not particularly limited. By adding alcohol, a part of the water glass is gelled and shrinkage at the time of freshness is reduced, so that the amount of shrinkage of the silicate gel at the time of hardening is mainly reduced and the adhesion to metal is reduced. The effect is also exhibited. Liquid alcohols have a greater gelling effect when fresh than powdered granules, but powdered granules are more convenient in terms of handling. These may be used properly according to the respective applications when producing a mortar or a concrete material using the curable composition, and the powder granule can be mixed as a powder when the premix material is used. Preferably, a liquid material is preferable in that the amount of addition can be appropriately adjusted at the time of product production in a factory. It should be noted that a powdery granule and a liquid can be used in combination.

The component (E) is used in an amount of 1 to 30 parts by weight based on 100 parts by weight of the water glass (C). If the content is less than 1 part by weight, the effect of reducing shrinkage is not sufficient.
When the amount exceeds 0 parts by weight, the water glass gels remarkably,
The function as an alkali stimulant is impaired, and the strength of the cured product becomes insufficient.

As the alkoxysilanes (F), commercially available ones can be used, but those having low toxicity and high flash point are preferred from the viewpoint of safety. Since such alkoxysilanes generate an alcohol group in the course of reaction with water glass, the addition of the same results in the reduction of shrinkage at the time of freshness as well as the addition of alcohols. Adhesion to tools can be further reduced.

The addition amount of the component (F) is preferably 0.2 to 5 parts by weight based on 100 parts by weight of the solid content of the water glass (C). Even if it exceeds 5 parts by weight, there is no adverse effect, but 5 parts by weight or less is preferable from the viewpoint of the effect of reducing shrinkage, improving workability and cost. When the amount is less than 0.2 parts by weight, there is almost no effect of the addition.

(G) The reactive siliceous particles are not particularly limited as long as they contain silica as a main component and have a pozzolanic activity by an alkali stimulant. It can be used regardless of its crystalline or amorphous state. For example, what is called volcanic glass, glass cullet, waste glass, waste molten slag and the like can be mentioned. By the way, from the viewpoint of resource recycling, by-products
Materials derived from waste are preferred, and materials that are themselves highly susceptible to corrosion by a corrosive liquid such as an acid are not preferred.

By adding the component (G), for example, shrinkage of the mortar after hardening can be further reduced, and the adhesion of the mortar material to a metal tool at the time of freshness is greatly improved, thereby improving workability. . The fineness of the particles is
The specific surface area may be 3000 cm ² / g or less, preferably 2000 cm ² / g or less, more preferably 1 cm ² / g or less.
At 500 cm ² / g or less, it is preferable that 90% or more of the total amount is 1200 μm or less, and more preferably 50% or more of the total amount is 150 μm or less.

The content of the component (G) is in the range of 5 to 60% by weight, preferably 10 to 50% by weight. At less than 5% by weight, the effect of improving workability is hardly recognized,
When the content is 0% by weight or more, no improvement in workability due to an increase in the content is particularly observed.

As the alkali metal hydroxide or alkali metal salt of the component (H), for example, sodium metasilicate, sodium orthosilicate, powdered sodium silicate No. 1, sodium hydroxide, potassium hydroxide, lithium hydroxide and the like can be used. However, sodium metasilicate, sodium orthosilicate, and sodium hydroxide are preferable, and two or more kinds can be used in combination. With these additions, -Si in water glass
The chain of -O-Si- is cut by the alkali to reduce the viscosity, the workability when used as mortar or concrete is further improved, and the addition of the alkali stimulates the molten slag to accelerate the hardening. The content of the component (H) is preferably 1 to 20% by weight, more preferably 2 to 5% by weight. When the content is 20% by weight or more, the effect of lowering the viscosity is not enhanced, and especially when the alkali metal hydroxide or the alkali metal salt having a high alkalinity is excessively contained, efflorescence is generated on the surface of the cured product Is not preferred. When the content is less than 1% by weight, the effect of the addition is hardly recognized.

The curable composition of the present invention further comprises an aggregate (I)
Can be contained. The mixing ratio of the aggregate is 30 to 500% by weight, preferably 30 to 300% by weight, based on the curable composition (not including the aggregate). As the aggregate, silicate fine aggregate or coarse aggregate is preferable. As the fine aggregate, river sand, sea sand, and crushed sand having the same particle size and particle size as those of silica sand, silica powder, and silica powder of Nos. 3 to 8 are preferable. . The mixing ratio of fine aggregate is as described above, but the mixing ratio of coarse aggregate is 5
It is preferably from 0 to 500% by weight, more preferably from 50 to 300% by weight. In addition, even if the mixing ratio of the aggregate exceeds 500% by weight, the acid resistance of the cured product can be obtained, but it is not preferable because the strength is reduced and the workability is deteriorated. On the other hand, if the mixing ratio of the aggregate is less than 30% by weight, the effect of mixing the aggregate cannot be sufficiently obtained.

The curable composition of the present invention can be used as a plaster mortar, grout material, backfill material, etc. by mixing a siliceous fine aggregate, adding an appropriate amount of water and kneading the mixture. Further, by using the molten slag of silica powder and a specific surface area 8000~12000cm ² / g of specific surface area 2500~3000cm ² / g adding an appropriate amount of water, it can also be used as ground grout. Needless to say, fine aggregate and coarse aggregate can be mixed and used as acid-resistant concrete.

When the curable composition of the present invention is used as a plaster mortar, a grout material, a backfill material, etc., the application method includes troweling, spraying, pumping, pouring, and the like. The curing method is usually performed at the environmental temperature of the construction site except during the cold season. During the cold season, heating and curing may be applied after construction to avoid frost damage. When used as acid-resistant concrete, there are pumping and pouring depending on the construction volume. The curing method is usually performed at the environmental temperature of the construction site, and may be heated in the cold season.

[0030]

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention thereto.

Comparative Example 1, Examples 1 to 20 (A) Secal BTF51 (made by Lafarge) as an alumina cement; (B) Blast furnace slag [CaO / SiO
₂ molar ratio: 1.38, specific surface area: 8000 cm ² / g];
(C) Water glass No. 1 and water glass No. 3 as water glass;
(D-1) Sewage sludge incineration molten slag [CaO / SiO ₂
Molar ratio: 0.46, specific surface area: 5000 cm ² / g];
(D-2) Metakaolin as metakaolin (manufactured by Asia Ceratech, [specific surface area: 12000 cm ² / g]); (H)
Sodium metasilicate powder as an alkali metal salt; (I) mixed silica sand as an aggregate [coarse particle ratio 1.74]; (E) methanol [m] as an alcohol, powder polyvinyl alcohol [p]; (F) as an alkoxysilane Decyltrimethoxysilane; (G) SiO ₂ as reactive silica particles
Amorphous with a chemical composition containing 72.0% and Na ₂ O 12%, having a vitrification ratio of 95% or more, and a particle diameter of 150 μm.
m sieve, 99.5% stays at 20 μm,
Was used. After weighing the mortar mixture having the mixing ratio shown in Table 1, adding water in consideration of the water content in the water glass, adjusting the total water content, and kneading the mixture, 40 × 40 × 160.
pours into a triple prism formwork, and removes the mold after 24 hours.
The length was measured by a method based on SA1129, and this was used as a reference length, and the change in drying shrinkage of each material age was measured. Further, since the drying shrinkage is easily affected by the amount of aggregate in the mortar, the values are set to be substantially the same in both the comparative example and the example.

[0032]

[Table 1]

For each material age, all of Examples 1 to 20 had values less than half the drying shrinkage of Comparative Example 1,
It shows excellent shrinkage reduction.

Comparative Example 2, Examples 21 to 27 Alumina cement The following materials were used in the same manner as in Example 1, and the mixed silica sand had a coarse particle ratio of 1.74. In addition, (F) powder polyvinyl alcohol [p] as the alcohol, and (G) SiO ₂ as the reactive silica particles.
Amorphous with a chemical composition containing 72.0% and Na ₂ O 12%, having a vitrification ratio of 95% or more, and a particle diameter of 150 μm.
A sieve that passes 99.5% at 20 μm was used. The mixture was weighed into a mortar mixture having a mixing ratio shown in Table 2, kneaded and molded in the same manner as in Example 1, and a change in drying shrinkage was measured. Similarly, in Comparative Example 2 and Examples 21 to 27, the aggregates are set to substantially the same values in both Comparative Examples and Examples.

[0035]

[Table 2]

In each of the ages, the values in all of Examples 21 to 27 are less than half the dry shrinkage of Comparative Example 2, indicating excellent shrinkage reduction.

Comparative Example 3, Examples 28 to 32 Alumina cement The following materials were used as in Example 21. After kneading at the mixing ratio shown in Table 3, the adhesion of the fresh mortar to the mortar spoon was measured and evaluated as follows. (Adhesion evaluation) Put an appropriate amount of mortar on a mortar spoon so that the mortar does not spill out from the spoon, and vertically shake the spoon to apply light vibration. All the mortar is peeled off, Δ: More than half of the fresh mortar is peeled off from the spoon, ×: Fresh mortar is not peeled off the spoon but remains on the spoon. ” The measurement was performed 10 times for each sample, and when a result corresponding to the lower evaluation was obtained, the lower evaluation was made.

[0038]

[Table 3]

As compared with Comparative Example 3, Examples 28 to 3
All two have improved workability. In particular, the effect of the reactive silica particles is excellent.

Comparative Example 4, Examples 33 to 37 Alumina cement The following materials were used in the same manner as in Example 21. In addition, the comparative example is an ordinary Portland cement [OP
C] was used. After kneading at the mixing ratio shown in Table 4, Φ5
After pouring into a 0 × 100 mm cylindrical form, curing in a moist air at 20 ° C. for 1 day, removing the mold and curing in water at 20 ° C. for 6 days, and immersing in a 5% by weight sulfuric acid solution, Acid resistance was evaluated based on the weight change at each age.

[0041]

[Table 4]

In comparison with Comparative Example 4, which is a cured product of a conventional cement-based material, which was significantly eroded by acid and reduced in weight, Examples 33 to 37 showed little change in appearance and shape. No change in weight, indicating excellent acid resistance.

[0043]

The use of the curable composition of the present invention makes it possible to remarkably reduce the shrinkage of the cured product during and after curing, so that there is little risk of cracking even in a severely dry environment, and it is resistant to acid. A cured product having excellent properties and durability can be obtained. In addition, the curable composition of the present invention has low adhesion to tools when used as fresh mortar or concrete, and has extremely good workability.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09K 17/10 C09K 17/10 P 17/12 17/12 P // (C04B 28/26 (C04B 28 / 26 18:14 18:14 A 18:04 18:04 24:42 24:42 A 24:02 24:02 7:32 7:32 22:08 22:08 A 22:06) 22:06) 111: 20 111: 20 111: 23 111: 23 C09K 103: 00 C09K 103: 00 F term (reference) 4D004 AA43 BA02 CA45 CC13 DA03 DA10 4G012 PA25 PA29 PB03 PB06 PB15 PB41 PC13 4H026 CA01 CA03 CA06 CB08 CC02

Claims (9)

[Claims] 1. The following components (A) to (D): (A) 5 to 70% by weight of alumina cement, (B) CaO / SiO ₂
2-40% by weight of molten slag powder having a molar ratio of 1.20 or more, (C) 5-40% by weight of water glass solids, (D)
CaO / molten slag powder in a molar ratio of SiO ₂ is 0.10~1.20 (D-1) and / or SiO ₂ -Al ₂ O ₃ reactive powder (D-2) containing 5 to 60 wt% (C) 1 to 100 parts by weight of solid content of water glass
A curable composition containing 30 parts by weight of (E) an alcohol. 2. The curable composition according to claim 1, wherein the molten slag of the component (B) is a blast furnace slag. 3. The curable composition according to claim 1, wherein the component (D) is a molten slag powder (D-1) having a CaO / SiO ₂ molar ratio of 0.10 to 1.20. 4. The curable composition according to claim 3, wherein the component (D-1) is a molten slag having a fineness of 2000 to 15000 cm ² / g in specific surface area. 5. The curing method according to claim 1, wherein (C) 0.2 to 5 parts by weight of an alkoxysilane is added to 100 parts by weight of the solid content of the water glass. Composition. 6. Further, (G) the fineness is 3,000 in specific surface area.
cm ² / g or less of the curable composition of any one of claims 1 to 5 containing 5 to 60 wt% reactive siliceous particles. 7. The method according to claim 1, further comprising (H) an alkali metal hydroxide and / or
The curable composition according to any one of claims 1 to 6, further comprising 1 to 20% by weight of an alkali metal salt. 8. A curable composition comprising the curable composition according to any one of claims 1 to 7 and an aggregate (I). 9. A cured product obtained by mixing the curable composition according to claim 1 with water and curing the mixture.