JP2928317B2 - Slag reduction agent for centrifugal force molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a slag reducing agent for centrifugal molded products, and more specifically, piles, poles, steel pipe composite piles manufactured by centrifugally molding mortar or concrete, The present invention relates to a slag reducing agent for centrifugal force forming that reduces or prevents the generation of slag when manufacturing a steel pipe lining and a fume tube centrifugal force molded product.

<Prior art and its problems> Conventionally, when manufacturing concrete products such as piles and poles manufactured by centrifugal force forming, squeeze is squeezed out by centrifugal force. In addition to water, this noro contains 20 to 40% by weight of cement and fine particles of sand as a solid content, and is strongly alkaline. However, there is a problem that it takes a lot of time and money for the treatment of sedimentation and filtration and the neutralization of wastewater.

In order to prevent the generation of this slag, silica fume,
It has been proposed to use a total of 15 parts by weight or more of fine mineral powder having a specific surface area of 6,000 to 9,000 cm ² / g with respect to 100 parts by weight of Portland cement in concrete (Japanese Patent Application Laid-Open No. Sho 62-7654). Gazette).

However, this method has a problem that it is uneconomical because the effect of not using more than 15 parts by weight, based on 100 parts by weight of Portland cement, in total amount of silica fume and mineral powder is not obtained. .

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that magnesium salts which have not been proposed as a slag reducing agent can achieve a slag reduction effect with a small amount. Was completed.

<Means for Solving the Problems> That is, the present invention is a slag reducing agent for centrifugal force forming, which contains magnesium salts and a soluble aluminum compound and / or an inorganic powder as main components.

 Hereinafter, the present invention will be described in detail.

Magnesium salts according to the present invention (hereinafter referred to as Mg salts)
Examples thereof include magnesium acetate, magnesium sulfate, magnesium nitrate, magnesium carbonate, basic magnesium carbonate, magnesium oxide, magnesium hydroxide and the like, and commercially available ones are usually used.

Depending on whether Mg salts are simply added as a powder at the time of kneading mortar or concrete, or in combination with a water reducing agent and added as an aqueous solution or suspension, the effect of reducing slag generation differs, but the amount of Mg salts used is At most 3 parts by weight, preferably 2 parts by weight or less, more preferably 1 part by weight or less, based on 100 parts by weight of cement. If the amount exceeds 3 parts by weight, the strength reduction rate due to an increase in the unit water amount increases, or depending on the type of Mg salt, slump drop becomes remarkable, and it becomes easy for a centrifugal molded body to form a jumper, which is not preferable.

Further, the lower limit of the amount of Mg salts used varies depending on the method of use, is not particularly limited, for example,
When used in combination with a water reducing agent, and added as an aqueous solution or suspension, even at 0.01 parts by weight, exhibits a noro reduction effect, with a water reducing agent,
By using bentonite among the inorganic powders described below,
When it is made into a suspension, even at 0.001 part by weight, the slag reduction effect is exhibited.

The mortar or concrete to which magnesium acetate, magnesium sulfate and magnesium nitrate are added among Mg salts increases the unit water amount, becomes a plastic, and improves water retention, thereby reducing slag. It is observed that salt and the like have a small increase / decrease in the unit water volume, but rather increase the viscosity of the concrete, and show the effect of reducing the generation of slag due to slump drop. And magnesium carbonate salt etc. is good for strength, but it is easy to generate junka in the centrifugal molded body, so as magnesium salts, magnesium acetate,
The use of magnesium sulfate and magnesium nitrate is preferred, and the use of magnesium acetate and magnesium sulfate is most preferred.

In the present invention, when a soluble aluminum compound and / or an inorganic powder are used in combination with Mg salts, the slag reduction effect is promoted.

Here, the soluble aluminum compound is one or more selected from the group consisting of aluminum sulfate, aluminum nitrate, sodium aluminate, potassium aluminate, alum, alumite and calcined alunite. Commercially available products for industrial use can be used as they are.

The soluble aluminum compound promotes the slag-preventing effect of Mg salts and is used in terms of anhydride.The amount used is at most 3.0 parts by weight in total with Mg salts per 100 parts by weight of cement. Preferably, it is 2.0 parts by weight or less, more preferably 1.5 parts by weight or less.

In addition, the lower limit of the total amount of the soluble aluminum compound and the Mg salts varies depending on the method of use and is not particularly limited.For example, when used in combination with a water reducing agent, and added as an aqueous solution or suspension, 0.005 A slag reduction effect is recognized from about part by weight, and when a suspension including bentonite in the inorganic powder is added and added, a slag reduction effect is exhibited from about 0.0005 parts by weight in total.

The mixing ratio of the Mg salt and the soluble aluminum compound is not particularly limited.

In the present invention, the inorganic powder refers to a clay mineral or a siliceous substance.

Examples of the clay mineral include bentonite, acid clay, activated clay, clay, zeolite, and talc.

As the silica substance, silica fume, aerosil and diatomaceous earth, and further, when the silica such as fused silica is pulverized, the maximum particle size collected by a back filter is 60 μm.
Ultra fine powder silica and the like.

In particular, the use of bentonite and silica fume is preferred in view of the effect of promoting the reduction of slag, economic efficiency and stability of the supply source.

Bentonite is a clay mineral belonging to the montmorillonite group and has a swelling property, but the higher the degree of swelling, the more the small amount of the clay mineral promotes the effect of reducing slag.

The swellability of bentonite differs depending on the production area and the deposit, and in general, the degree of swelling of bentonite is determined by the ACC method (Americannn).
Those having a degree of swelling of about 5 to 40 according to Collid Campany standard are commercially available. Bentonite has a different swelling effect depending on its degree of swelling. For the same amount used, the larger the degree of swelling, the greater the effect of reducing slag, and the degree of swelling is 10%.
It is preferable to use the above bentonite.

Further, silica fume is amorphous silica as an ultrafine powder that is by-produced during the production of metallic silicon or a silicon alloy.

In the present invention, among the inorganic powders, those containing water of crystallization are added in terms of anhydrous salts, and those containing many impurities are added in terms of active ingredients.

The addition amount of the inorganic powder is preferably at most 5 parts by weight, more preferably 3 parts by weight or less, further preferably 2 parts by weight or less, based on 100 parts by weight of cement in mortar or concrete. If it exceeds 5 parts by weight, the amount of kneading water increases and there is a component that lowers the strength, which is not preferable.

The lower limit of the addition amount of the inorganic powder varies depending on the method of use and is not particularly limited.For example, as described above, by using in combination with a Mg salt or a water reducing agent, and adding it as a suspension, In particular, bentonite has an effect of promoting slag reduction even with a small addition of 0.01 part by weight with respect to 100 parts by weight of cement.

In the present invention, the combined use of a slag reducing agent for centrifugal force molding and a water reducing agent is preferred. In particular, when the centrifugal force-forming slag reducing agent of the present invention is added as a powder or when it is simply added as a suspension, an aqueous solution or a suspension together with a water reducing agent is used in an extremely small amount. , Showing a slag reduction or prevention effect.

Examples of the water reducing agent used in the present invention include a general water reducing agent, an AE water reducing agent, and a high-performance water reducing agent, and the components are not particularly limited. Specifically, it is possible to use a general water reducing agent such as a lignin sulfonate, an oxycarboxylate and a polyol or a high-performance water reducing agent. Above all,
It is preferable to use a high-performance water reducing agent that has a large water reduction rate and can control the water reduction rate by the amount of water used.

A high-performance water reducing agent is a water reducing agent having a large water reduction rate that does not cause air entrainment or excessive setting delay even when used in a relatively large amount, and further does not cause abnormal setting, such as polyalkylallyl sulfonate and melamine. Formalin resin sulfonate and the like.

Generally, commercially available high-performance water reducing agents are those containing any one of the above as main components, and polyalkylallyl sulfonates include naphthalenesulfonic acid formalin condensate, methylnaphthalenesulfonic acid formalin condensate and anthracenesulfonic acid. Formalin condensate and the like, and as a commercially available product, “Mighty 10
“0” and “Mighty 150”, such as “Cell Flow 110P” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., “Pole Fine 510N” manufactured by Takemoto Yushi Co., Ltd. “Sanyo Kokusaku Pulp Co., Ltd.” There are "Sunflow PS" and "Sunflow PSR", and the product name "FT-500" manufactured by Denki Kagaku Kogyo Co., Ltd. As the melamine formalin resin sulfonate, the product name "Showa Denko Co., Ltd." Examples include "Melment F-10" and "Melment F-20", and the trade name "NL-400" manufactured by Nisso Master Builders Co., Ltd.

In the present invention, the amount of the water reducing agent used for cement may be the amount specified by the manufacturer or 2
The amount is about 3 to 3 times, and the amount does not cause abnormal coagulation.

When using a high-performance water reducing agent as a water reducing agent,
0.3 to 2.0 parts by weight, preferably 0.4 to 1.8 parts by weight, more preferably 0.5 to
1.5 parts by weight is more preferred. As the amount of high-performance water reducing agent used increases, the water reduction rate increases,
The slag increases and the required amount of the slag reducing agent for centrifugal force forming of the present invention for reducing the slag increases. When the use amount of the high-performance water reducing agent is less than 0.3 parts by weight and the centrifugal force forming noro reducer of the present invention is used, concrete becomes plastic,
As the mixing water increases, the decrease in strength tends to increase.
Exceeding parts by weight increases the viscosity of concrete,
This is not preferable because the effect of the slag reducing agent tends to decrease.

The cement used in the present invention includes various portland cements such as ordinary / early strong / super fast / moderate heat, various mixed cements in which portland cement is mixed with fly ash, silica and blast furnace slag, and fine powder of blast furnace slag. The use of a high-strength admixture containing gypsum or the like as a main component or an expanding material is not particularly limited.

As a method of kneading mortar or concrete, it is sufficiently possible to use a conventional method. In addition, the method for adding the slag reducing agent for centrifugal force molding of the present invention may be such that the powders are separately or mixed and charged into a mixer, or may be added in advance as an aqueous solution, but may be added in advance as a water reducing agent. Most preferably, they are used in combination as an aqueous solution or suspension. Specifically, it is most convenient to measure the water-reducing agent and the centrifugal force-forming slag reducing agent together with the kneading water, and to stir and add them to the kneading water measuring tank.

The centrifugal force forming method is also not particularly limited, and is a conventional method of G No. 3 to 5 at a low speed of 1 to 3 minutes, a medium speed of G No. 12 to 18 at a medium speed of 3 to 5 minutes, and a G No. 30 to It is preferable to carry out at a high speed of 40 for 3 to 5 minutes, but when the mortar or concrete using the centrifugal force-forming slag reducing agent of the present invention is, for example, a low slump of 3 cm or less, the mortar or concrete at the time of centrifugal force molding is used. For example, it is preferable to perform the low speed at G No. 3 or less for 3 minutes or more. If G No.3 is exceeded, it is easy to generate a junker along the circumferential direction within 1-2 cm from the outer diameter of the centrifugal molding, and if the centrifugal molding is not performed for 3 minutes or more, mortar or Concrete may not rotate. At medium speed, there is no need to be particular about the G No. and the centrifugal force forming time. The high speed is preferably G No. 27 or more when calculated from the inner diameter up to the inside of the tube thickness of the centrifugal molded body. If G is less than 27, mortar or concrete may not be formed properly on the inner surface. In such a case, it is preferable to re-mold again with G No. 27 or more. The high-speed time is preferably 1 minute or more.

Furthermore, vibration centrifugal molding, which is performed while vibrating at a low or medium speed, is preferable because it does not easily produce a jumper even with mortar or concrete that is difficult to move with plastic, and the finish of the molded body is improved.

<Example> Hereinafter, the present invention will be described in detail based on examples.

REFERENCE EXAMPLE 1 Concrete shown in Table 1 was used, and as shown in Table 2, a water reducing agent was used, the type and amount of Mg salts were changed, the concrete was kneaded, and the centrifugal force of φ20 × 30 ^l × 5 ^t was used. Packed in a mold for molding, cover the hollow part of the mold so that slag does not leak, and use G No.
Centrifugal force molding was performed under the centrifugal molding conditions of low speed of o.2 for 4 minutes, medium speed of G No.4 for 2 minutes, and high speed of G No.35 for 2 minutes, and the amount of squeezed out was measured.

Similarly, a concrete specimen of φ10 × 20cm was prepared by vibration stuffing, pre-cured at 20 ° C for 4 hours, and then 15 ° C / h
After raising the temperature to 65 ° C at a heating rate of 4 hours and holding for 4 hours,
The steam valve was stopped, the mixture was naturally cooled in the curing tank as it was until the next day, then demolded, cured in a room at 20 ° C. until 7 days after demolding, and then measured for compressive strength.

For kneading the concrete, kneading water in which a water reducing agent was dissolved was added to dry mortar in which cement, various Mg salts, sand and crushed stone were kneaded, and the concrete was kneaded for 30 minutes. At this time, the fluctuation of the unit water amount when the water reducing agent and various Mg salts were added was kneaded as it was without correcting the blending.

Table 2 shows the unit water amount and slump along with the test results.

The Mg salts and the water reducing agent were expressed in terms of solids, anhydride, or active ingredient in parts by weight based on 100 parts by weight of cement.

<Materials> Cement: Ordinary Portland cement manufactured by Denki Kagaku Kogyo Co., Ltd., specific gravity 3.16 Sand: Himekawa, Niigata Prefecture, river sand, specific gravity 2.65 Crushed stone: Same as above, crushed stone, specific gravity 2.68 Mg salts A: magnesium acetate, reagent grade B: sulfuric acid Magnesium, reagent grade C: magnesium sulfate, reagent grade D: magnesium carbonate, reagent grade E: basic magnesium carbonate, reagent grade F: magnesium oxide, reagent grade G: magnesium hydroxide, reagent grade water reducing agent α: Daiichi Kogyo Seiyaku Product name "Selflo-11"
0P "Polyalkylallyl sulfonate-based powder.

The asterisks in Table-2 indicate that the end of the centrifugally molded body was junk.

As shown in Table 2, Mg salts show a remarkable slag reduction effect, and the addition effect becomes remarkable from 0.05 part by weight with respect to 100 parts by weight of cement when added as powder, and the addition amount is increased. As a result, no slag occurs.

On the other hand, when the amount of addition is increased, the decrease in strength is increased due to an increase in the unit water amount, and when the amount exceeds 3 parts by weight, there is a case where the strength becomes lower than plain strength which is concrete strength without a water reducing agent. In addition, if the amount of water exceeds 3 parts by weight, the unit water content does not increase and the strength does not decrease. If the amount exceeds 3 parts by weight, the concrete lacks the elongation ability during the centrifugal force forming, and it is easy to generate junka.

Reference Example 2 As shown in Table 3, the same procedure as in Reference Example 1 was carried out except that the type and amount of the water reducing agent were changed. Table 3 shows the results.
It is described together.

<Material used> Water reducing agent β: trade name “Merment F-1” manufactured by Showa Denko KK
0 "Principal component melamine formalin resin sulfonate, powder.

γ: Denka Grace Co., Ltd. product name “Darlex WRDA” standard addition amount cement × 0.4%, lignin sulfonate-based, liquid.

The combined use of a water reducing agent is also preferable from the viewpoint of suppressing the strength reduction due to an increase in the unit water amount, and a high performance water reducing agent capable of controlling the water reducing agent ratio by the amount of addition is particularly preferable. Since a high-performance water reducing agent has a low water reduction rate when added in a small amount, in order to secure plain strength, the amount of Mg salts added cannot be increased, and the slag reduction effect tends to be incomplete. Conversely, in the case of adding a large amount, even if the addition amount of the Mg salt is increased, the slag reduction effect becomes inferior, preferably at most 2 parts by weight or less, more preferably 0.3 to 1.8 parts by weight, and 0.4 to 1.5 parts by weight. Parts by weight are most preferred.

Reference Example 3 For Experiments Nos. 1-3 to 6 and 26 to 31, cement, sand and crushed stone in dry mortar, a water reducing agent and an aqueous solution in which Mg salts were dissolved or suspended in the total amount of kneading water were prepared. The concrete was kneaded by adding it, and the amount of slag generated when centrifugal molding was performed in the same manner as in Reference Example 1 was measured. The results are shown in Table-4.

As shown in Table 4, Mg salts are used in combination with a water reducing agent,
By using an aqueous solution or a suspension, the slag reduction effect is increased.

Example 1 The same test as in Reference Example 1 was carried out on the concrete used in Table 1 and the materials used in Reference Example 1 by changing the type and amount of soluble aluminum compound as shown in Table-5. . The results are shown in Table-5.

In addition, the soluble aluminum compound was mixed with other components in a powder state in the same manner as in Reference Example 1, kneaded with cement, sand and crushed stone, and then kneaded water in which a water reducing agent was dissolved was added. Was kneaded.

Each component was expressed in terms of anhydride, active ingredient or solid content in terms of parts by weight based on 100 parts by weight of cement.

<Materials used> Soluble aluminum compound a: Aluminum sulfate, first-class reagent manufactured by Wako Pure Chemical Industries, Ltd. b: Calcined alumite, 600 of alumite from Katsumitsuyama, Hiroshima Prefecture
℃ baked and pulverized product, Blaine 3,000cm ² / g, purity 90% c: potassium alum, first grade reagent manufactured by Wako Pure Chemical Industries, Ltd., active ingredient 90% d: aluminum nitrate, manufactured by Wako Pure Chemical Co., Ltd. 1 Grade reagent, active ingredient 90% e: Sodium aluminate Wako Pure Chemical Co., Ltd. first grade reagent,
Active ingredient 90% In Table-5, the asterisks (*) indicate that the end of the centrifugal force molded product was junk.

As shown in Table-5, the combined use of the soluble aluminum compound promotes the slag reduction effect of the Mg salts, and shows that the larger the amount of addition, the greater the slag reduction effect.

When the total amount of the soluble aluminum compound is more than 3 parts by weight, a decrease in strength due to an increase in the amount of unit water is large, or the centrifugal force molded product is liable to become a junk, which is not preferable.

Example 2 As shown in Table 6, the same procedure as in Example 1 was performed except that an inorganic powder was used instead of the soluble aluminum compound. The results are shown in Table-6.

<Materials used> Inorganic powder a: Bentonite, trade name "Premium Gel" manufactured by Kanto Bentonite Industry Co., Ltd. 35 swelling degree by ACC method b: Bentonite, trade name "Granulation" manufactured by Toyoshun Mining Co., Ltd.
ACC method swelling degree 10 c: Acid clay, Kanto bentonite industrial Co., Ltd. product name "acid clay" d: Activated clay, Kanto bentonite industrial product trade name "Galeon earth" E: Clay, Kanto bentonite industrial ) Product name "SAM Clay" F: Zeolite, Kanto Bentonite Industry Co., Ltd. product name "SGW" To: Talc, Kanto Bentonite Industry Co., Ltd. product name "Soapstone A" J: Silica Fume, Nippon Heavy Chemical Industry Product name "SF Powder" manufactured by Co., Ltd. Re: Aerosil, product name "Aerosil 50" manufactured by Nippon Aerosil Co., Ltd. Nu: Diatomaceous earth, calcined product from Noto Wakura L: Fused silica, manufactured by Denki Kagaku Kogyo Co., Ltd. , Back filter product when crushed fused silica, maximum particle size 60μ As shown in Table 6, when the inorganic powder is used in combination with the powder, a remarkable effect is exhibited from about 0.05 part by weight, and the strength decrease becomes large when the inorganic powder exceeds 5.0 parts by weight. Is not preferred.

Example 3 As shown in Table 7, the same procedure as in Example 1 was performed except that Mg salts, a soluble aluminum compound, an inorganic powder, and a water reducing agent were used. The results are shown in Table-7.

Example 4 Experiment Nos. 4-1 to 4, 4-16 to 20, 5-1 to 4 and 6-
Using concrete of Nos. 1 to 6, Mg salts, a soluble aluminum compound and / or an inorganic powder were used in combination with a water reducing agent, suspended in kneading water, and added to dry kneaded dry concrete. Was tested. The test results are shown in Table-8.

As shown in Table-8, the slag reducing agent for centrifugal force forming of the present invention exerts a slag reducing effect in a small amount when used as a suspension containing a water reducing agent.

<Effect of the Invention> As described above, the use of the slag reducing agent for centrifugal force forming of the present invention reduces the generation of slag in piles and the like manufactured by centrifugal force forming by adding a small amount. Or, it can be prevented, and the time and cost normally spent for the slag treatment can be reduced, and the slag treatment equipment is not required.

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI C04B 22/06 C04B 22/06 Z 22/08 22/08 B Z 22/10 22/10 22/14 22/14 A // B28B 1/20 B28B 1/20 21/30 21/30 (58) Fields studied (Int. Cl. ⁶ , DB name) C04B 24/04 C04B 22/06-22/10 C04B 22/14 C04B 14/04 , 14 / 08,14 / 10 B28B 21/30 B28B 1/20

Claims (1)

(57) [Claims] 1. A slag reducing agent for centrifugal force molding, comprising magnesium salts, a soluble aluminum compound and / or an inorganic powder as main components.