JPH03265552A - Whitewash reducing agent - Google Patents

Abstract

PURPOSE:To reduce or prevent the generation of a whitewash when a centrifugal formed article is produced from mortar or cement by composing the agent essentially of a soluble aluminum compd. and limes and/or an inorg. powder. CONSTITUTION:The whitewash reducing agent for a centrifugal formed article consists essentially of a soluble aluminum compd. and limes and/or an inorg. powder. Aluminum sulfate, aluminum nitrate, sodium aluminate, alum, etc., are exemplified as the soluble aluminum compd. to be used. A maximum of 3 pts.wt., expressed in terms of the anhydride, of the soluble aluminum compd. is used with 100 pts.wt. of the cement in mortar or concrete. At>3 pts.wt., the strength is remarkably lowered due to an increase in the mixing water quantity, and further the mortar or concrete may be quickly set.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a slag reducing agent for centrifugally formed products, and more specifically, piles, balls, steel pipe composite piles, etc. manufactured by centrifugally forming mortar or concrete. The present invention relates to a slag reducing agent that reduces or prevents the generation of slag during the manufacture of centrifugally formed products such as steel pipe linings and humid pipes.

<Conventional technology and its problems> Conventionally, when manufacturing concrete products such as piles and poles that are manufactured by centrifugal force forming, slag is squeezed out by centrifugal force. In addition to water, this slag contains 20 to 40% by weight of solid particles of cement and sand, and is strongly alkaline, so it is impossible to release the odor outside the factory to prevent pollution. Problems include the fact that it takes a lot of time and money to perform solid content sedimentation, filtration, deodorizing treatment, and neutralization of wastewater.

In order to prevent the formation of slag, a method is known in which a setting accelerator such as aluminum sulfate is added to the concrete while pouring it into the formwork, and centrifugal force forming is performed (JP-A-61-104804). ).

However, with this method, although the separation of solids can be suppressed, the amount of strongly alkaline water to be dehydrated increases, so a neutralization tank is required to process this. .

As a result of intensive study from the standpoint of not releasing any water or slag, the present inventors used a soluble aluminum compound such as aluminum sulfate, lime and/or a specific inorganic powder, and combined it with mortar or concrete. The present invention was completed based on the knowledge that the above-mentioned problems can be solved by kneading them together.

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

The present invention will be explained in detail below.

The soluble aluminum compounds according to the present invention include aluminum sulfate, aluminum nitrate, sodium aluminate,
One or more selected from the group consisting of potassium aluminate, alum, alumite, and calcined alumite,
It is possible to use those commercially available for industrial use as they are.

The amount of the soluble aluminum compound used is preferably at most 3 parts by weight, more preferably 2 parts by weight or less, and 0.05 to 1.5 parts by weight in terms of anhydride, per 100 parts by weight of cement in mortar or concrete. part is most preferred.

If it exceeds 3 parts by weight, the strength tends to decrease further due to an increase in the amount of cross-conducting water, and furthermore, the mortar or concrete may set rapidly, which is not preferable.

The limes according to the present invention are quicklime and slaked lime, and quicklime contained in the expanding agent can also be used, which promotes the slag reduction effect of the soluble aluminum compound and speeds up the setting and hardening of mortar or concrete. It also has the effect of speeding up the process and increasing strength. These are commercially available products that can be used as they are.

The amount of lime used is preferably at most 5 parts by weight, more preferably 0.05 to 3 parts by weight, per 100 parts by weight of cement in the mortar or concrete.

If it exceeds 5 parts by weight, the setting promotion effect is too strong and the strength tends to decrease, which is not preferable.

Inorganic powders according to the present invention include bentonite, acid clay, activated clay, clay, clay minerals such as zeolite and talc, silica hume, aerosil and diatomaceous earth, and furthermore, when pulverizing silica such as fused silica, a hack filter is used. Examples include ultrafine silica with a maximum particle diameter of about 60 μm, and among these, bentonite and silica hume are preferable because they have a large effect of promoting slag reduction.

Bentonite has swelling properties, and its swelling properties vary depending on the production area and ore deposit.
Those having a swelling degree of about 5 to 40 according to Cann Co11id CaIII pany standard) are commercially available. The effect of bentonite in reducing slag varies depending on its degree of swelling, and when used in the same amount, the greater the degree of swelling, the greater the effect of reducing slag (it is preferable to use bentonite with a degree of swelling of 10 or more.

Furthermore, silica fume is ultrafine amorphous silica that is produced as a by-product during the production of metal silicon and silicon alloys.

The amount of these inorganic powders used is preferably at most 5 parts by weight, more preferably 3 parts by weight or less, and 0.0 parts by weight or less, per 100 parts by weight of cement in mortar or concrete.
More preferably 5 to 2M parts.

If it exceeds 5 parts by weight, the amount of kneading water will increase and there will be components that reduce strength, which is not preferable.

The slag reducing agent of the present invention is preferably used in combination with a water reducing agent.

The slag reducing agent may be used as a powder, but by dispersing it in a slurry form with the water reducing agent and, if necessary, dispersing it in part or all of the kneading water, you can more effectively reduce slag with a small amount. It becomes possible to do this.

The water reducing agent used in the present invention includes a boat fishing water reducing agent, a high performance water reducing agent, and the like, and is not particularly limited in terms of its components. Specifically, common water reducing agents and high performance water reducing agents such as lignin sulfonate, oxycarboxylic acid salt, and polyol can be used. Among these, 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 adjusting the amount used.

A high-performance water reducing agent is a water reducing agent with a high water reduction rate that does not cause air entrainment, excessive setting delay, or abnormal setting even when used in a relatively large amount. Examples include melamine formalin resin sulfonate.

Generally available commercially available high-performance water reducing agents contain any of the above-mentioned main ingredients, and examples of polyalkylaryl sulfonate-based salts include naphthalene sulfonic acid formalin condensate,
Examples include methylnaphthalenesulfonic acid formalin condensate and anthracene sulfonic acid formalin condensate, and commercially available products include Kao's product name "Mighty 100" and [
Mighty 150J, etc. are manufactured by Daiichi Kogyo Seiyaku ■ such as Cell Flow 110 PJ, Yuki Yushi ■ Pole Fine 51 ONJ, and Sanyo Kokusaku Pulp ■ are manufactured by Sanflow PSJ and Sanflow PSRJ. , and Denki Kagaku Kogyo ■ product name rPT-500J, etc., and as melamine formalin resin sulfonate, Showa Denko ■
Product name [Melment F-10J and [Melment F-2]
Product name: 0J etc. manufactured by Nisso Master Builders ■ rNL-
Examples include 4000J.

In the present invention, the amount of water reducing agent used for cement is:
- In the case of water reducing agent for boat fishing, the amount specified by the manufacturer or 2-3
It is used in approximately twice the amount and within the range that does not cause abnormal coagulation.

In addition, when using a high-performance water reducing agent as a water reducing agent, the solid content should be 0.3 to 2.0 per 00 parts by weight of cement.
Parts by weight are preferred, 0.4 to 1.8 parts by weight are more preferred, and even more preferably 0.5 to 1.5 parts by weight.

As the amount of high-performance water reducing agent used increases, although the water reduction rate increases, the amount of slag increases, and the amount of the slag reducing agent of the present invention required to reduce slag also increases. When the slag reducing agent of the present invention is used in an amount of less than 0.3 parts by weight of the high-performance water reducing agent, concrete becomes plastic;
The amount of kneading water increases and the strength tends to decrease significantly<,2.
If it exceeds 0 parts by weight, the viscosity of the concrete increases and the effect of the slag reducing agent tends to decrease, which is not preferable.

The cement used in the present invention is normal, early strength, super early strength,
These include various types of Portland cement such as moderate heat, various mixed cements made by blending Portland cement with blast furnace slag, fly ash, or silica, and cement containing pulverized blast furnace slag.

The slag reducer of the present invention can be added directly as a powder into a mixer and kneaded, but it is more effective to make it into a slurry by suspending it in a water reducer and, if necessary, water. Specifically, it is preferable to measure water, a water reducing agent, and a slag reducing agent at the same time into a measuring device, stir to form a suspension, and then introduce the suspension into a mixer and knead it.

The kneading method is not particularly limited, and methods commonly used in the production of mortar or concrete can be used.

The centrifugal force forming method is also not particularly limited, and can be used for 1 to 3 minutes at a low speed of GN α 3 to 5, 3 to 5 minutes at a medium speed of G k12 to 18, and 3 to 5 minutes at a high speed of GN 030 to 40. However, if the mortar or concrete using the slag reducing agent of the present invention has a low slump, for example, 3 cm or less, the mortar or concrete will be difficult to move during centrifugal forming. It is preferable to do this for 3 minutes or more.

When GNα exceeds 3, junkers are likely to be generated along the circumferential direction at 1 to 21 points inside from the outer diameter of the centrifugal force formed body,
In addition, if centrifugal force forming is not performed for 3 minutes or more, the mortar or concrete may not reach the edges. Medium speed is
There is no need to be particular about GNα and centrifugal force forming time.
Normally, GNCL9±5 should be used for more than 1 minute.The high speed is calculated based on the inner diameter of the centrifugal force molded body to the inside of the tube thickness.
K27 or higher is recommended. If Gk is less than 27, mortar or concrete may not be formed properly on the inner surface. Further, the high speed time is preferably 1 minute or more.

Furthermore, vibratory centrifugal force molding, in which molding is performed while vibrating at low or medium speeds, is preferred because junkers are less likely to form even in plastic and hard-to-move mortar or concrete, and the molded product has a good finish.

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

Example 1 Using the basic mix of concrete shown in Table-1, as shown in Table-2, a g
Using aluminum acid (-grade reagent) and β slaked lime (digested gas-fired lime, 88μ or less) as lime, changing the amount used and mixing concrete, φ20X30'
Put 18kg of concrete into a 5t x formwork,
After covering the hollow part of the form to prevent slag from leaking, use GNa measured with the center diameter of the wall thickness.
II! [L2 low speed for 4 minutes, CNcL5 medium speed for 2 minutes,
Knead under centrifugal force forming conditions for 2 minutes at high speed of Ck35,
After a few minutes, a centrifugal molded body was molded, and the amount of slag squeezed out was measured.

Similarly, a concrete specimen of φ10 x 20C11 was prepared, pre-cured at 20℃ for 4 hours, and then cured for 15 hours.
The temperature was raised to 65°C at a rate of °C/h, and after steam curing for 4 hours, the steam valve was stopped and the material was left to cool naturally in the curing tank until the next day, after which it was taken out and the material aged 7. The compressive strength was measured after curing in a room at 20°C until 15 days.

In addition, when the soluble aluminum compound and lime were used, they were kneaded as they were without making any correction for the increase or decrease in the unit water amount. Table showing the amount of water used and slump value along with the test results.
Also listed in 2.

The slag reducing agent of the present invention was mixed with cement to form dry concrete with sand and crushed stone, and kneading water was added thereto to knead the concrete.

Materials used: Cement: Ordinary Portland cement made by Denki Kagaku Kogyo ■, specific gravity 3.16 Sand: River sand, specific gravity 2.65 crushed stone from Himeyo, Niigata Prefecture
: Same as above, crushed stone, specific gravity 2.68 Soluble aluminum compound a: Aluminum sulfate, Wako Pure Chemical's first class reagent Lime β: Slaked lime, calcined in a gas calcined lime furnace, crushed to 88 μm whole, and added with water Digested material Table 1 Example 2 As shown in Table 3, Example 1 except that the type of soluble aluminum compound was further changed and a water reducing agent was used in combination.
I did the same thing. The results are also listed in Table-3.

Materials used> Soluble aluminum compound calcined alumite, potash alum from Katsumitsu, Hiroshima prefecture, crushed to 3,0OOafl/g by Blaine, fired at 600°C, purity 90%C: aluminum nitrate, Wako pure First class reagent manufactured by Yakuza d: Sodium aluminate, e: Potassium alum, Water reducer ii: Product name manufactured by Dai-Kogyo Seiyaku Co., Ltd. [Cellflow 110
Pj main component polyalkylaryl sulfonate system, powder.

In Table 3, the water reducing agent, soluble aluminum compound and lime are shown in parts by weight based on 2100 parts by weight of cement. When the water reducing agent is powder, the soluble aluminum compound and lime are mixed, cement, sand and Crushed stone was added during dry kneading, and the condensate was added to adjust the slump.

In addition, the water reducing agent is dissolved in the mixing water and added to the air-mixed dry concrete containing the slag reducing agent. Among the soluble aluminum compounds, those with crystallization water are calculated on an anhydride basis, and those containing impurities are calculated on an active ingredient basis. It was kneaded as

As shown in Table 3, the addition of a soluble aluminum compound alone has a small effect on reducing the generation of slag, but the combined use of limes reduces or prevents the generation of slag.

Soluble aluminum compounds show an effect when added from 0.05 parts by weight to 100 parts by weight of cement, and the greater the amount used, the greater the slag reduction effect.
If it exceeds 1 part by weight, the rate of decrease in strength will be large due to the increase in the unit amount of water, and the strength may fall below the plain strength without the addition of a water reducing agent, which is not preferred).

Lime shows an effect when used at around 0.05 parts by weight per 100 parts by weight of cement, and as the amount used increases, it promotes the effect of reducing slag and contributes to increasing strength.
If the amount exceeds 5 parts by weight, the rate of strength development becomes too high, resulting in a decrease in strength.
, 2-1 and Experiment No. 2-3 comparative example, and Experiment Nα2-10
The concrete of Example was formed into a formwork of φ1010 x 20, immediately placed in a curing tank at 60°C, and after curing for 3 hours, the compressive strength was 50.80 and 250 kgf/, respectively.
cd, and it is recognized that the combination of soluble aluminum compounds and limes significantly accelerates setting and hardening.

Example 3 As shown in Table 4, the same procedure as in Example 1 was conducted except that aluminum sulfate was used as the soluble aluminum compound, the types and amounts of lime and water reducing agent were changed, and concrete was kneaded. The results are also listed in Table-4.

<Materials used> Lime α: Quicklime, calcined in a gas calcined lime furnace and crushed into 88μ whole pieces Water reducing agent mouth: Showa Denko Product name [Melmen] F-1OJ
Main ingredient: melamine-formalin resin sulfonate, powder.

C: Made by Denka Grace ■Product name [Dare Nkusu Ane DA
J standard addition amount Cement) Xo, 25%, main component lignin sulfonate system, liquid.

Example 4 As shown in Table 5, the same procedure as Example 1 was carried out except that inorganic powder was used in place of lime. Display the results -
Also listed in 5.

<Materials used> Inorganic powder A: Bentonite, Kanto Bentonite Industry ■
Product Name F Premium Gel JA, C, C Method Swelling Degree 35 B: Bentonite, Toyojun Mining Co., Ltd. Product Name F Sized JA, C
, C method swelling degree 10 C: Acid clay, manufactured by Kanto Bentonite Industries ■Product name [Acidic clay] D: Activated clay, manufactured by Kanto Bentonite Industries ■Product name "Galeon Earth J" E: Clay, manufactured by Kanto Bentonite Industries ■Product name rsAM
Clay” F: Zeolite, manufactured by Kanto Bentonite Industries ■Product name rs
GWJ G: Talc, Kanto Bentonite Industries ■Product name "Soapstone A" H: Silica hume, Japan Heavy Chemical Industry ■Product name rSF
Powder j 1: Aerosil, Nippon Anirosil ■Product name: Aerosil 50J J: Diatomaceous earth, calcined product from Noto Wakura: Fused silica, made by Denki Kagaku Kogyo ■, bank filter product when pulverized fused silica, maximum Particle size: 50μ As shown in Table 5, inorganic powders of clay minerals and silica substances have been shown to promote the slag reduction effect of soluble aluminum compounds from about 0.05 parts by weight per 100 parts by weight of cement. , even if added in excess of 5 parts by weight,
It is shown that an increase in the unit amount of water only causes a decrease in strength, which is economically unfavorable.

Example 5 As shown in Table 6, the same procedure as in Example 1 was conducted except that a soluble aluminum compound, lime, inorganic powder, and water reducing agent were used. The results are also listed in Table-5.

Example 6 Experimental results in Table 3 2-4.2-7 to 9.2-16 to 18.
222, Experiments N114-1 to 4 in Table 5 and Experiments 51 to 3 in Table 6, each component and water reducing agent were made into a suspension with the entire amount of mixing water, and added to dry concrete that had been mixed, The same centrifugal molding as in Example 1 was performed, and the amount of slag generated was measured. The results are shown in Table-7.

Table 7 As shown in Table 7, the slag reducing agent of the present invention is more effective in small amounts than by adding the water reducing agent and each component as a suspension in advance, compared to adding it as a powder. It is recognized that slag can be reduced or completely prevented.

<Effects of the Invention> As described above, by using the slag reducing agent of the present invention, it is possible to reduce or completely prevent the slag generated during the production of piles, etc., and the time normally spent on slag treatment can be reduced. It becomes possible to significantly reduce costs.

Claims (1)

[Claims] (1) A slag reducing agent for centrifugal force-molded products, the main components of which are a soluble aluminum compound, lime and/or inorganic powder.