JPS6183660A - Manufacture of early strength cement product - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention provides 1! of cement products! ! ! It is about creating and leaving. For more details, see 1 Cement Product I! ! ? The present invention relates to a method for manufacturing a cement product that is highly effective in increasing the initial strength, especially in the steam curing process.

Conventionally, various studies have been made for the purpose of improving the initial strength of cement products, and several methods have been adopted. for example,
These include increasing the amount of cement per unit, extending the steam curing time, reducing mixing water by using various cement dispersants, and using cement hardening accelerators.

However, none of these methods has been able to provide sufficiently consistent results for the following reasons. That is, an increase in the amount of cement per unit is undesirable because it uses a large amount of cement, which increases the cost per unit volume, and also tends to cause cracks in the product.

Additionally, extending the steam curing time also increases the amount of steam used.

Alternatively, it is not preferable because the cost increases due to a decrease in the rotation rate of the plastic.

The use of various cement dispersants has been widely used in recent years for the purpose of improving the strength of cement products, and representative old TC ones include atomyl sulfonate, oxydicarboxylate, and
Although various agents such as naphthalene sulfonic acid formalin condensate type and melamine sulfonic acid formalin condensate type have been used, it cannot be said that they have sufficient performance in terms of improving initial strength. Cement hardening accelerators include metal chlorides such as calcium monochloride and sodium chloride, metal sulfates such as sodium sulfate, organic amines, and lower aliphatic carboxylates such as formates and acetates. It is put into practical use. However, metal chlorides are corrosive to reinforcing bars or metal forms, and metal sulfates have problems in solubility in water and ability to accelerate hardening.

In addition, organic amines have a low ability to accelerate hardening, and if used in an incorrectly large amount, they have the disadvantage of significantly reducing strength. In addition, mono-lower aliphatic carboxylic acid salts have the disadvantage that their ability to accelerate cement hardening is extremely low.

In addition, these curing accelerators generally have dispersibility in themselves, but on the contrary, they tend to inhibit the fluidity ratio of concrete, so they are comparable in terms of workability.

Under such circumstances, the inventors of the tree found that the strength development effect of Kawamei was effective1.
As a result of tax consideration regarding a manufacturing method for cement products that increases the fluidity ratio of concrete and has excellent workability, 1. Surprisingly, a naphthalene sulfonic acid formalin condensate has no ability to accelerate cement hardening when used alone. salt or/and melamine sulfonic acid formalin condensate salt,
We have discovered that scales can significantly improve initial strength when used in combination with a polycarboxylic acid compound (salt), which has a significantly low ability to accelerate cement hardening when used alone, resulting in the present invention! child.

The polycarboxylic acid compound (salt) contains some known curing accelerators such as oxalic acid (salt), but when used alone, this has a significantly low accelerating ability.

That is, 1 the present invention uses 02 to 0.8% of naphthalene sulfonic acid formalin condensate salt and/or melamine sulfonic acid formalin condensate salt and 0005 to 0.06% of polycarboxylic acid compound (salt) based on the weight of cement. This is a method for manufacturing a plastic cement product that develops early strength.

The naphthalene sulfonic acid formalin condensate salt used in the present invention is a product obtained by highly condensing naphthalene sulfonic acid with formalin and neutralizing it with caustic soda monocalcium hydroxide.
Those listed in Japanese Patent Publication No. 48-9564 may be used. Naphthalene sulfonic acid has α-naphthalene sulfonic acid and β-naphthalene sulfonic acid.
-Naphthalene sulfonic acid is preferred, and β-naphthalene sulfonic acid is preferred. 5 In the present invention, in addition to the formalin condensate salt of naphthalene sulfonic acid, aromatic compounds and/or these sulfonic acids may be added to the naphthalene sulfonic acid formalin condensate salt as long as the performance is not inhibited. Co-condensed products are also included. Examples of these include JP-A-51-17219° and JP-A-50-29.
644. Examples include those described in Japanese Patent Application Laid-Open No. 50-58120, and one other variety. Examples of these are aromatic compounds such as naphthalene and athracene; aromatic sulfonic acids such as benzenesulfonic acid, anthracene sulfonic acid; toluenesulfonic acid, dodecylbenzenesulfonic acid, methylnaphthalinosulfonic acid, ethylnaphthalene sulfonic acid. Alkyl substituted aromatic sulfonic acids such as acids; alkoxy substituted benzene sulfonic acids such as methoxybenzenesulfonic acid; hydroxy substituted benzene sulfonic acids such as phenolsulfonic acid; alkyl and alkoxy substituted benzene sulfonic acids such as nignisulfonic acid; cresol Examples include alkyl and hydroxy substituted benzene sulfonic acids such as sulfonic acids.

The amount of aromatic compounds and/or these aromatic sulfonic acids co-condensed with naphthalene sulfonic acid to an extent that does not impair its performance is generally 30 parts by weight or less per 100 parts by weight of naphthalene sulfonic acid.

In addition, as the naphthalene sulfonic acid formalin condensate salt used in the present invention, sodium salt is usually used, but
In addition, alkali metal salts such as lithium salts and potassium salts, divalent metal salts such as calcium salts, magnesium salts, zinc salts, and iron salts.

It can also be used as trivalent metal salts such as aluminum salts, iron salts, and other ammonium salts.

It can also be used as an organic amine salt or an alkanolamine salt, or a combination of 2FA or more of these various salts may be used. Further, the salt of a melamine sulfonic acid formalin condensate used in the present invention is a salt obtained by condensing melamine sulfonic acid with formalin, and may be a commercially available salt. For example, Melment manufactured by Showa Denko 0 Ltd., NL-4000 and NP-20 manufactured by Zezoris Bussan fall under this category. The salt of this melamine sulfonic acid formalin condensate can be prepared by mixing general (melamine and formaldehyde or paraformaldehyde, sulfite C, sodium sulfite, ammonium sulfite, sodium bisulfite, ammonium bisulfite, etc.) in water under alkaline conditions (for example, pH 9 to 12), those subjected to an addition reaction under alkaline conditions and further condensed under weakly acidic conditions (e.g. pH 4 to 6), and those subjected to an addition reaction under alkaline conditions. Examples include those obtained by condensing to a high degree under strong acidity (for example, pH 2 to 4). Among these, those which are highly condensed under strong acidity are more preferable than those having a cement content of 1. Further, among the salts of naphthalene sulfonic acid formalin condensate and the salts of melamine sulfonic acid formalin acid compound used in the present invention, the salt of naphthalene sulfonic acid formalin condensate is preferable from the viewpoint of cement dispersion ability and early strength. be.

The polycarboxylic acid compounds (salts) used in the present invention include aliphatic unsaturated dicarboxylic acids such as maleic acid, fumaric acid, mesaconic acid, citraconic acid, and itaconic acid; oxalic acid and malonic acid.

Succinic acid, glutaric acid, adipic acid, pimelic acid.

Aliphatic saturated dicarboxylic acids such as superric acid, azelaic acid, and sebacic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid; and volatile tricarboxylic acids such as tricarballylic acid and benzenetricarboxylic acid. I can name things. Salts include lithium and sodium.

Examples include alkali metal salts such as potassium, divalent metal salts such as calcium, magnesium, zinc, and iron, and trivalent metal salts such as aluminum and iron.
It can also be used as a salt of organic amines, alkanolamines, etc. Furthermore, two or more of these various salts may be used in combination.

Among these various salts, sodium salts of maleic acid and fumaric acid are preferred because they have high early strength.

Particularly preferred is the sodium salt of maleic acid.

In the wood invention, it is essential to use naphthalene sulfonic acid formalin condensate salt and/or melamine sulfonic acid formalin condensate salt within the range of 02 to 0.8% (purity %) based on the weight of cement. Even if it is less than 0.2%, o
, s O is also undesirable because the early strength decreases. 03-0.6% in terms of the highest early strength
It is more preferable to use it within the following range. In addition, 1 polycarbonate compound (salt) is also 0005 to 0 relative to the cement weight.
It is essential to use within the range of 0.06% (purity %).

In this case, even if it is less than 0.005% or more than 0.006%, the early strength will decrease, which is not preferable. It is also preferable to use f1 in an amount of 0.008 to 0.05%. In addition, when maleic acid (salt) or fumaric acid (salt) is used alone without using naphthalene sulfonic acid formalin condensate salt or melamine sulfonic acid formalin condensate salt, the usage amount that gives the highest early strength is 0.08 to 0.12%, which is significantly different from the additional amount of the present invention. The reason for this is unknown.

Cement products that use the method of Wood Invention include concrete and mortar for on-site pouring used in civil engineering and construction;
Various types of concrete and mortar secondary products produced in factories can be mentioned, but it is particularly preferable to use it for manufacturing secondary products produced in factories because it has excellent early strength development during steam curing. . Examples of such secondary products include centrifugally molded concrete and mortar such as piles, balls, and humid pipes, molding molded concrete and mortar such as box culvert 1 shield segments, U-shaped grooves, road slabs, and various blocks. You should be able to bring up something that you can criticize.

In the present invention, other components (optional components) may be used as necessary.
can also be added. Such optional ingredients include known air entraining agents such as alkylbendan sulfonate, sulfuric acid ester salt of wounded fatty acid alkylenoxide adduct, 1vinsol; ligninosulfonate, 1polyalkylene glycol, styrene sulfonic acid. Polymers, copolymers with styrene sulfonic acid monoethylenic monomers, oxycarboxylic acid salts, polyethylene sulfonate 1α, copolymers of β-unsaturated dicarboxylic acids and chain olefins.

Known cement dispersants selected from sulfonic acid salts of heavy aromatic hydrocarbons, melamine sulfonic acid formalin condensates, lignin sulfonic acid, and gluconic acid.

Known cement hardening retardants such as citric acid, salt, polyphosphoric acid; known glue agents such as polyvinyl alcohol, starch, methyl cellulose, and hydroxymethyl cellulose; known rust preventive agents such as sodium nitrite, calcium nitrite, etc. I can list many things.

In the present invention, naphthalene sulfonic acid formalin condensate salt and/or melamine sulfonic acid formalin condensate salt and polycarboxylic acid compound (salt) are usually mixed with cement and framework (sand, crushed stone, etc.) and added to kneading water. Although it is sometimes added to cement, it may be added to cement (-2 after mixing aggregate, water, 1 after cement is hydrated by contact, 1 to 2 minutes or more after mixing), or 1 after being added to cement in advance. , an addition method of adding water may also be used. Furthermore, a divided addition method may be used in which a part of the product of the present invention is added during kneading, and then the remaining dispersant of the present invention is added in one or more divided portions.

Examples of cement that can be used in the method of the present invention include ordinary Portland cement, early-strength Portland cement, medium-heat Portland cement, alumina cement, and fly ash cement. Among these, preferred are ordinary Portland cement and early strength Portland cement.

The present invention will be explained below with reference to one example, but the present invention is not limited thereto.

Example - (The combination ratio of naphthalene sulfonic acid formalin condensate (NSF) and sodium maleate was varied by 8.

Steam curing of concrete and demolding strength were measured.

At the same time, the concrete steam-cured strength was measured when the amount of IIO added was varied using sodium maleate alone.

Materials used: Cement: Ordinary Bolt Land Cement: Coarse aggregate: Takatsuki Ibaraki crushed stone F.M '6.8 B, specific gravity: 2
．． 65 Fine aggregate: Produced river sand for stagnation F-M 2.95, specific gravity 254 Steam curing conditions: After mixing with concrete at 20°C, the temperature was raised to 65°C for 1 hour at intervals in 2 hours. After curing at the same temperature for 4 hours. Immediately, the early release and compressive strength were measured.

Table 1 shows each compounding condition and theory ♀j strength. Figure-1 is Table-1
This is a graph of the results.

Table 1 and Figure 1 show that the demolding strength of concrete using NSF and sodium maleate is significantly higher than that of concrete using sodium maleate alone or concrete using NSF alone. I can see that it is.

Example 2 The steam curing demolding strength of concrete using N5F and sodium fumarate was measured.

The amount of NSF used was 0.4% versus 70%, and the amount of sodium fumarate added was varied.

The materials used and steam curing conditions are the same as in Example-1. Table 2 shows the test results.

Similar to sodium maleate, sodium fumarate also
It can be seen that when used in combination with NSF, the demolding strength of 1 concrete can be significantly increased.

Example 4 When 04% NSF is used in cement.

For each case in which no sodium oxalate was used, the demolding strength was measured in the same manner as in Example 1 by changing the amount of sodium oxalate added, and the results shown in Table 4 were obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram in which the testing results of Example 1 are plotted in terms of the amount of maleate and the strength upon demolding. Solid lines A, B, C, D, and E each indicate NSF at 0°0.2
．． The demolding strength at each concentration of sodium maleate when added at 0.4, 0.6, and 0.8% is shown.

Claims (1)

[Claims] 1. 0.2 to 0.8% of naphthalene sulfonic acid formalin condensate salt and/or melamine sulfonic acid formalin condensate salt and polycarboxylic acid compound (
1. A method for producing an early strength-developing cement product, characterized by using 0.005 to 0.06% of salt). 2. The manufacturing method according to item 1, wherein the polycarboxylic acid compound (salt) is maleic acid (salt) or/and fumaric acid (salt). 3. The manufacturing method according to item 1, characterized in that naphthalene sulfonic acid formalin condensate salt is used in an amount of 0.3 to 0.5% and sodium maleate is used in an amount of 0.008 to 0.05% based on the weight of the cement.