JPH05186251A - Additive for centrifugal molding of mortar or concrete - Google Patents

Abstract

PURPOSE:To provide an additive capable of giving mortars or concretes extremely reduced in the generation of lime wash and rich in the flowability and also of giving mortar- or concrete-centrifugal molded products having excellent compression strengths, to provide the centrifugally molded products containing the additive, and further to provide a method for producing the molded products. CONSTITUTION:When a mortar- or concrete-centrifugally molded product is produced, a mortal or concrete containing a mortar or concrete additive used for mortar- or concrete-centrifugal molding and comprising 100 pts.wt. of inorganic fine powder obtained by treating fly ash at a high temperature and 10-100 pts.wt. of a high performance-reducing agent is centrifugally molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mortar or concrete centrifugal molding additive, and more specifically, a mortar or concrete centrifugal molding additive, a mortar or concrete centrifugal molding containing the same, and the molded product. The present invention relates to a method of efficiently producing

[0002]

2. Description of the Related Art When mortar or concrete is centrifugally molded to form a mortar or concrete centrifugally molded product such as a fume pipe or pile, the water contained in the mortar or concrete is used. And a waste liquid generally called Noro, which mainly consists of cement paste and fine particles having a relatively low specific gravity, is generated.

Since a large amount of disposal cost is required for the disposal processing of the slag, a technique for suppressing or reducing the generation thereof is desired. On the other hand, from the standpoint of workability, an additive that maintains the fluidity of mortar or concrete and has a water reducing effect is desired.

As one of such techniques, for example, a concrete material such as cement or fine aggregate is mixed (added) with an inorganic fine powder such as activated silica (Japanese Patent Publication No. Sho 64).
-7024), amorphous ultrafine particle silica (JP-A-61-122174), or ultra-fine particle (JP-A-59-215808). It is known to mold by a centrifugal force method. According to these methods, the water content in the mortar or concrete can be reduced, but the generation of slag cannot be sufficiently suppressed.

The present invention solves the above-mentioned conventional problems, has less slag, and is highly fluid.
Provided are an additive for mortar or concrete centrifugal forming, which can give a mortar or concrete centrifugal forming excellent in compressive strength, a mortar or concrete centrifugal forming containing the same, and a method for efficiently producing the formed body. The purpose is to do.

[0006]

That is, the present invention provides an additive for mortar or concrete centrifugal molding, which comprises an inorganic fine powder obtained by high-temperature treatment of fly ash and a high-performance water reducing agent.

In the present invention, an inorganic fine powder obtained by subjecting fly ash to a high temperature treatment (hereinafter sometimes referred to simply as an inorganic fine powder obtained from fly ash) is used. Here, if the fly ash is simply used, the occurrence of slag cannot be prevented and the object of the present invention cannot be achieved.

The inorganic fine powder obtained from fly ash used in the present invention usually has a specific surface area of 10,000 to 1
It is 300,000 cm ² / g and has a SiO ₂ content of 50 to 80% by weight. If the specific surface area of the inorganic fine powder obtained from fly ash is less than 10,000 cm ² / g, generation of slag in centrifugal force molding can be suppressed to some extent, but slag immediately after the start of centrifugal force molding can be suppressed. Is insufficient, and especially when centrifugal molding is performed immediately after kneading concrete, the effect of preventing formation of slag is inferior, which is not preferable.

In the high temperature treatment method of fly ash, the fly ash is jetted from a nozzle into a heating furnace to which fuel and oxides are supplied, and the temperature inside the heating furnace is controlled by a specific oxide contained in the fly ash. Maintaining a temperature above the boiling point, thereby inducing the oxide vapor outside the heating furnace and cooling it, the first step of collecting the particles, having a boiling point higher than the boiling point of the specific oxide, and heating It consists of the second step of separating and recovering other oxides which are not vaporized in the furnace from the bottom of the heating furnace. Further, by changing various conditions, the shape of the oxide to be separated and recovered can be changed. The inorganic fine powder obtained from fly ash used in the present invention is a spherical fine powder obtained by treating fly ash in a melting furnace at a high temperature of about 2300 to 3000 ° C., and having a ratio of 20 surface area
10,000 to 1.2 million cm ² / g and a SiO ₂ content of 60 to
70% by weight is preferable. The specific surface area is BE
The measurement was performed by the T method, and the adsorption gas was nitrogen.

In the present invention, inorganic fine powder obtained from the fly ash to which slag powder is added may be used. That is, a mixture of an inorganic fine powder obtained from fly ash and a slag powder may be used, and this may be combined with a high-performance water reducing agent described later. Examples of the slag powder include, for example, slag discharged from the lower part of the combustion furnace when the inorganic fine powder obtained from the fly ash is produced, and pulverized granulated slag obtained by quenching in water. be able to. The mixing ratio of the inorganic fine powder obtained from fly ash and the slag powder is less than 50% by weight, preferably 45% by weight or less, and more preferably 40% by weight or less. Here, if the mixing ratio of the slag powder exceeds 50% by weight, it becomes difficult to suppress the occurrence of slag, which is not preferable.

Next, in the present invention, it is necessary to use a high-performance water reducing agent together with the inorganic fine powder obtained from fly ash as described above. Here, when only the inorganic fine powder obtained from fly ash is used, the slump value of mortar or concrete is extremely low, and it becomes difficult to perform centrifugal molding. On the other hand, when only the high-performance water reducing agent is used, it becomes difficult to suppress the occurrence of slag.

The high-performance water reducing agent used in the present invention may be any admixture having a water reducing effect, and various types can be used including an AE water reducing agent having an air entraining action. Specifically, for example, a salt of a formalin condensate of naphthalene sulfonic acid, a salt of a formalin condensate of alkylnaphthalene sulfonic acid, a salt of a formalin condensate of naphthalene sulfonic acid and an alkyl naphthalene sulfonic acid, a salt of naphthalene sulfonic acid and a lignin sulfonic acid. Formalin condensate salts, lignin sulfonic acid salts, melamine formalin condensate sulfonates, polycarboxylic acid salts consisting of maleic acid and acrylic acid type copolymer salts,
Polystyrene sulfonates, sulfonated styrene-maleic acid copolymer salts, salts of sulfonated formalin condensates of creosote oil, salts of formalin condensates of sulfonated heavy aromatic hydrocarbon oils, etc. You can The salts of these substances are preferably sodium salt, potassium salt, calcium salt, ammonium salt and the like.

Among these, as the high-performance water reducing agent used in the present invention, a salt of a formalin condensate of naphthalene sulfonic acid, a salt of a sulfonated styrene-maleic acid copolymer, a polystyrene sulfonate, etc. are particularly preferable. , And more preferably a weight average molecular weight of 500 to
Mention may be made of millions of sulfonated styrene-maleic acid copolymer salts and polystyrene sulfonates.

The additive for mortar or concrete centrifugal molding of the present invention comprises a high-performance water reducing agent and an inorganic fine powder (or a mixture of inorganic fine powder and slag powder) obtained from fly ash as described above. Can be obtained by

In the present invention, 100 parts by weight of the inorganic fine powder (or the mixture of the inorganic fine powder and the slag powder) obtained from the fly ash as described above is usually mixed with 10 parts of the above-mentioned high performance water reducing agent. To 100 parts by weight, preferably 20 to 30 parts by weight. If the blending ratio of the superplasticizer is less than 10 parts by weight, the slump value of mortar or concrete becomes extremely low,
It becomes difficult to perform centrifugal molding. On the other hand, if the blending ratio of the high-performance water reducing agent exceeds 100 parts by weight, the slump value of the mortar or concrete becomes high and the amount of slag generation increases, which is not preferable.

The additive for mortar or concrete centrifugal molding of the present invention as described above is used by adding it to mortar or concrete when producing a mortar or concrete centrifugal molding. Here, the mortar is composed of cement, sand and water, and the concrete is composed of cement, sand, gravel and water.

In the present invention, these mortars or concretes may be mixed with inorganic fine powder obtained from fly ash (or a mixture of inorganic fine powder and slag powder) and a high-performance water reducing agent. Alternatively, both may be added separately to mortar or concrete.

In this case, the additive for mortar or concrete centrifugal forming of the present invention is added to cement in an amount of 0.1 to 10% by weight, particularly 1.5 to 5% by weight in terms of solid content. Is preferred.

If the amount of the additive of the present invention added is less than 0.1% by weight, the slump value of the mortar or concrete is low and centrifugal molding becomes difficult, which is not preferable. On the other hand, if the addition amount of the additive of the present invention exceeds 10% by weight, the effect commensurate with the addition amount cannot be obtained and the concrete strength decreases, which is not preferable.

A mortar or concrete centrifugal force molding can be produced by adding the mortar or concrete centrifugal force molding additive as described above to mortar or concrete and subjecting it to centrifugal force molding.

In the present invention, the mortar or concrete centrifugal forming material is added by adding the mortar or concrete centrifugal forming additive as described above, and using the mortar or concrete containing the additive,
It is possible to produce a mortar or concrete centrifugal force molded body that has little slag generation, is highly fluid, and has excellent compressive strength.

Centrifugal force molding may be carried out by a conventional method.
Usually, mortar or concrete is packed in a mold, and the mold is placed on the wheels of a centrifuge and rotated to gradually increase the number of rotations. Mortar or concrete is pressed against the mold surface by centrifugal force, water is squeezed inward, and a centrifugal force molded body is obtained, but by further curing it, the desired centrifugal force molded body can be obtained. Is obtained.

Although the effect of compacting the centrifugal force increases with an increase in the number of revolutions, it has an adverse effect if the revolution speed is too high. Therefore, it is usually performed at about 3 to 12 G for 2 to 10 minutes and then 25 at the time of compaction.
It is preferable to carry out at about 35 G for about 5 to 10 minutes.

When performing centrifugal forming, other known additives such as retarder, hardening accelerator, air entraining agent, air entraining water reducing agent may be added together with the additive for mortar or concrete centrifugal forming of the present invention. Agents and other auxiliary ingredients can be added as appropriate.

[0025]

EXAMPLES Next, the present invention will be described in more detail by way of examples. Production Example 1 (Production of water reducing agent A) Styrene having a weight average molecular weight of 6,500 and an acid value of 350 mgKOH / g
100 g of maleic acid copolymer was added to ethylene dichloride 5
It dissolved in 00 g. A sulfonating agent prepared by dissolving 45 g of anhydrous sulfuric acid in 300 g of ethylene dichloride was added dropwise to this solution over 4 hours while maintaining the reaction temperature at 30 ° C. After completion of dropping, the reaction solution was filtered to remove the solvent, and then dried at 50 ° C. under reduced pressure. Then, 30 g of caustic soda and 260 g of water were added to 100 g of the sulfonated styrene-maleic acid copolymer thus obtained, and the mixture was stirred at 80 ° C for 30 minutes to give a sulfonated styrene-maleic acid copolymer. 390 g of a 30% by weight aqueous solution of the combined sodium salt was obtained, which was used as a water reducing agent A.

Production Example 2 (Production of water reducing agent B) 100 g of styrene oligomer having a weight average molecular weight of 8,500
Was dissolved in 500 g of ethylene dichloride. To this solution, add a sulfonating agent prepared by dissolving 80 g of sulfuric anhydride in 300 g of ethylene dichloride while keeping the reaction temperature at 30 ° C.
It dripped over time. After completion of dropping, the reaction solution was filtered to remove the solvent, and then dried at 50 ° C. under reduced pressure. Then the sulfonated styrene oligomer 100 thus obtained
To g, add caustic soda 26 g and water 254 g, and at 80 ℃
The mixture was stirred for 30 minutes to obtain 380 g of a 30% by weight aqueous solution of a sodium salt of a sulfonated styrene oligomer, which was designated as a water reducing agent B.

Production Example 3 (Production of Inorganic Fine Powder = Production of Neofume) An electrostatic precipitator-collecting fly ash (composition and properties shown below) discharged from a coal-fired power generation facility was used to burn pulverized coal and oxygen. Temperature in the furnace formed by
A fixed amount was supplied to an ultra-high temperature combustion furnace at 0 ° C. The composition of fly ash (unit: weight%) is SiO ₂ : 56.0, Al
_{20 3} : 23.4, Fe ₂ O ₃ : 3.5, CaO: 1.
2, TiO ₂ : 1.2, MgO: 1.1, Na ₂ O:
1.0, K ₂ O: 1.5, Ig. Loss: 3.
It was 3. The average particle size was 30 μm.

This combustion furnace is formed of a refrigerant jacket surrounding the periphery, a refrigerant inlet and a refrigerant outlet of the refrigerant jacket, an oxidizer (oxygen), a fuel (pulverized coal), and a jet nozzle of fly ash. .. Further, in the upper part of the combustion furnace, there are provided a cooling pipe extending in the horizontal direction, a refrigerant jacket surrounding the periphery thereof, a refrigerant inlet and a refrigerant outlet of the refrigerant jacket, and a cyclone separator and a bag on the downstream side. A filter type dust collector and a suction fan are provided. Since the inside of the ultra-high temperature combustion furnace is set to 2500 to 2600 ° C, which is slightly higher than the boiling point of SiO ₂ (2230 ° C), the low boiling point components including SiO ₂ become steam, which is rapidly cooled in the cooling part in the upper part of the combustion furnace. A fume having the following composition and properties was obtained.

Composition of the obtained fumes (unit:% by weight)
Is SiO ₂ : 70.0, Al ₂ O ₃ : 19.0, Fe ₂
O ₃ : 3.6, CaO: 1.1, TiO ₂ : 0.7, M
gO: 0.8, Na ₂ O: 0.9, K ₂ O: 1.6, Ig. Loss: 0.1. The specific surface area was 51.3 m ² / g and the average particle size was 0.06 μm. The specific surface area was measured by the BET method, and the average particle diameter was measured by an electron micrograph (the same applies hereinafter). The specific surface area is 1 by changing the cooling rate.
It can be varied from 0 to 130 m ² / g. In addition, by converting the type of fly ash used as a raw material and coexistence with other raw materials (silica stone, limestone, etc.), SiO ₂
The purity can be varied as 50 to 85%.

Production Example 4 (Production of Mixture of Inorganic Fine Powder and Slag Crushed Product) (1) Production of Slag Crushed Product Using the fly ash used in Production Example 3 as a raw material, the cooling rate is 50% higher than that of Production Example 3. Except for the setting, the same procedure as in Production Example 3 was carried out to obtain a fumes having the following composition and properties. Composition of the obtained fumes (unit:
Wt%) of _{SiO 2: 71.4, Al 2 0} 3: 18.
_{2, Fe 2 O 3: 3.7} , CaO: 1.2, TiO 2:
0.6, MgO: 1.0, Na ₂ O: 1.0, K ₂ O:
1.7 and Ig. Loss: 0.1. Further, the specific surface area is 102 m ² / g, and the average particle size is 0.1.
It was 02 μm.

Next, during the production of the above fumes, the slag discharged from the lower part of the combustion furnace was rapidly cooled in water to obtain granulated slag. The granulated slag was pulverized by a horizontal type annular wet pulverizer with a slurry concentration of 70% and a residence time of 8 minutes to obtain a slag pulverized product having the following composition and properties. The composition (unit: weight%) of the slag crushed product thus obtained is SiO ₂ : 58.3, Al
_{20 3} : 29.4, Fe ₂ O ₃ : 3.2, CaO: 1.
0, TiO ₂ : 0.9, MgO: 1.1, Na ₂ O:
0.8, K ₂ O: 1.4, Ig. Loss: 0.
It was 2. The specific surface area was 12 m ² / g and the average particle size was 4.5 μm.

(2) Manufacture of a mixture of inorganic fine powder and slag pulverized product: The inorganic fine powder (neofume) obtained in Production Example 3;
The former and the latter (weight ratio) are 2.5: 7.5 (fine powder mixture product A) and 5.0: 5.0 (fine powder mixture), respectively, with the slag crushed product obtained in (1) above. Item B), 6.0:
4.0 ((fine powder mixture C), 7.0: 3.0 (fine powder mixture D), 8.0: 2.0 (fine powder mixture E) Five types of mixtures were obtained.

Examples 1-9, Comparative Examples 1-8 and Reference Example 1
In a twin-shaft forced agitation mixer with a capacity of up to 250 liters, the specified amounts of cement, fine aggregate (sand), coarse aggregate (gravel), water and additives (admixture) shown in Table 1 below are used. Was added and stirred for 2 minutes to prepare 20 liters of concrete composition.
The temperature of the concrete composition was adjusted to 18 to 20 ° C. After measuring the slump value of the concrete composition thus obtained, 15 kg of this concrete composition
20 cm in diameter, 30 cm in height, and 4 cm in thickness were packed into a hollow centrifugal force test specimen, and the initial speed was 3 G for 2 minutes, and then the medium speed was 10 G for 1 minute.
Centrifugal molding was performed under the conditions of high speed 25 G for 1.5 minutes. The centrifugal molding was carried out for two members, one immediately after preparation of the concrete composition (after 1 minute) and 20 minutes after preparation. After centrifugal molding, the amount of slag discharged was measured for each centrifugal molding. After centrifugal molding, 3
After standing for a period of time, the temperature was raised to 75 ° C. at a temperature rising rate of 20 ° C./hr, and kept as it was for 5 hours for curing. Then, the mixture was naturally cooled, demolded the next day, and subjected to normal autoclave curing, and then the compressive strength of each was measured. The results are shown in Table 1. The maximum size of the coarse aggregate was 20 mm, the water / cement ratio was 34.6%, and the fine aggregate ratio (fine aggregate / fine aggregate + coarse aggregate) was 42.7%.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

* 1: Made by Chichibu Cement Co., Ltd. * 2: Made by Chichibu Cement Co., Ltd. * 3: Made by Chichibu Cement Co., Ltd. * 4: Made in Iwase, Ibaraki Prefecture (specific gravity: 2.59) * 5: Made in Awano, Tochigi prefecture (specific gravity: 2.63) ) * 6: IPC-550 (Idemitsu Petrochemical Co., Ltd., naphthalene sulfonic acid formalin condensate salt composition) * 7: Mighty 200 (Kao Corporation, naphthalene sulfonic acid formalin condensate salt composition) * 8 : What was obtained in Production Example 1 * 9: What was obtained in Production Example 2 * 10: What was obtained in Production Example 3 * 11: What was obtained in Production Example 4 * 12: Essent (Nippon Steel Chemical Co., Ltd. Co., Ltd., specific surface area 4,300 cm ² / g (by BET method) * 13: Silica fume (Nippon Heavy Industries, Ltd., specific surface area 283,200 cm ² / g (by BET method), SiO ₂ content 95.5% by weight , Al ₂ O ₃ content of 0 1% by weight,
Unburned carbon 1.1% by weight)

[0038]

According to the additive for mortar or concrete centrifugal forming of the present invention, a mortar or concrete centrifugal forming material having less slag generation, rich fluidity and excellent compressive strength is provided. be able to.
Further, in the method of the present invention, since the mortar or the concrete centrifugal force molded product is manufactured using the mortar or the concrete to which the mortar or the concrete centrifugal force additive as described above is added, the occurrence of slag is extremely small, and It is possible to produce a mortar or concrete centrifugal compact having a high fluidity and an excellent compressive strength. Therefore, the present invention can be effectively used for the production of mortar or concrete secondary products.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jiro Yasumura 1-1, Shingucho, Tokuyama City, Yamaguchi Prefecture, Idemitsu Petrochemical Co., Ltd. (72) Hideharu Shimokawa 1-1, Marunouchi, Chiyoda-ku, Tokyo At Kopetrochemical Co., Ltd. (72) Inventor Kazuo Iwami 1-35-3 Onuma, Kasukabe City, Saitama Prefecture (72) Inventor Yoshitaka Ito 4-8-13 Kokubunjidai, Ebina City, Kanagawa Prefecture Inventor Toshiaki Miyamoto Ibaraki Prefecture 4-2-1, Higashihonmachi, Furukawa City (72) Inventor Shunkuni Sera 2-5-1, Marunouchi, Chiyoda-ku, Tokyo Within Sanryo Heavy Industries Co., Ltd. (72) Toshiyuki Takekawa 1-1, Atsunoura-cho, Nagasaki City, Nagasaki Prefecture Mitsubishi Heavy industry Nagasaki Research Institute

Claims (4)

[Claims] 1. An additive for mortar or concrete centrifugal molding, which comprises an inorganic fine powder obtained by treating fly ash at a high temperature and a high-performance water reducing agent. 2. A mortar or concrete centrifugal molding product containing the additive for mortar or concrete centrifugal molding according to claim 1. 3. When producing a mortar or concrete centrifugal molding product, centrifugal molding is carried out using mortar or concrete to which the additive for mortar or concrete centrifugal molding according to claim 1 is added. A method for producing a mortar or concrete centrifugal compact. 4. An additive for mortar or concrete centrifugal molding, which comprises a mixture of inorganic fine powder and slag powder obtained by high-temperature treatment of fly ash and a high-performance water reducing agent.