JP2000313648A - Mechanical strength enhancer for cement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mechanical strength enhancer for concrete and the like by including an alkanolamine and a polyoxyalkylene block copolymer to reduce air-entraining tendency involved in the alkanolamine. SOLUTION: In this enhancer, combination of an alkanolamine with a polyoxyalkylene block copolymer, the two components of this promotor, enables selective reduction in only the air entraining tendency involved in the alkanolamine without affecting the air entrainment tendency involved in an AE agent or AE water reducing agent. The polyoxyalkylene block copolymer is shown by the formula (R1 is a hydrocarbon group or acyl group; R2 is H, a hydrocarbon group or acyl group; A1 and A2 are each a >=3C alkylene group; E is ethylene group; (a), b and c are each a number >=1). The alkanolamine is pref. triisopropanolamine; for exhibiting the high defoaming performance of the alkanolamine, it is preferable that R1 is a 8-36C alkyl group, alkenyl group or acyl group, and R2 is hydrogen atom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a hardened cement body,
The present invention relates to a cement strength enhancer for increasing the strength of mortar or concrete (hereinafter referred to as “concrete or the like”).

[0002]

2. Description of the Related Art Conventionally, as a method for increasing the strength of concrete or the like, generally, activation of a hydration reaction of cement by addition of a chloride such as calcium chloride and water cement by addition of a high-performance (AE) water reducing agent are known. Methods such as reduction of the ratio are known.

However, in the above method, since chloride ions are introduced into concrete or the like, there is a disadvantage that this causes corrosion of steel such as reinforcing steel. In addition, the method does not promote the hydration itself of cement, but rather increases the strength by increasing the density of the structure of concrete or the like. There is a disadvantage that problems such as cracks due to drying shrinkage tend to occur.

[0004] On the other hand, triisopropanolamine (hereinafter sometimes referred to as “TIPA”), which is one of the alkanolamines, promotes the hydration of cement having a relatively large ferrite phase and increases the strength of concrete or the like. (The 50th Annual Meeting of the Cement Technology Conference, etc.) Such a compound has a remarkable effect particularly on the enhancement of long-term strength of concrete and the like, and has a feature that the strength is increased in accordance with the added amount and does not corrode steel materials such as reinforcing steel.

However, since TIPA has a strong foaming power, if it is added in an amount of about 0.005 parts by weight or more with respect to 100 parts by weight of cement, air is excessively entrained in concrete or the like, and on the contrary, the strength is reduced and the carbonation is reduced. There is a disadvantage that long-term durability is reduced due to acceleration and salt damage. Also, this TI
The problem of air entrainment of PA cannot be solved by the addition of a commercially available defoamer such as silicone or mineral oil.
IPA could not be used in an amount of about 0.005 parts by weight or more based on 100 parts by weight of cement.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a strength enhancer for cement for improving the strength of concrete or the like, in which the air entrainment of alkanolamine such as TIPA is reduced.

[0007]

Means for Solving the Problems In view of such circumstances, the present inventors have conducted intensive studies, and as a result, have found that alkanolamines and polyoxyalkylene block copolymers represented by the following general formula (1) can be used in combination. If it does not affect the air entrainment of the AE agent or AE water reducing agent, it is possible to selectively reduce only the air entrainment of the alkanolamine,
The present inventors have found that high-strength concrete and the like can be obtained and completed the present invention.

That is, the present invention relates to an alkanolamine and a compound represented by the following general formula (1):

[0009]

Embedded image R ¹ O- (A ¹ O) _a- (EO) _b- (A ² O) _c -R ² (1)

[In the formula, R ¹ represents a hydrocarbon group or an acyl group, R ² represents a hydrogen atom, a hydrocarbon group or an acyl group, A ¹ and A ² represent an alkylene group having 3 or more carbon atoms, E represents an ethylene group, and a, b and c each represent a number of 1 or more.] A cement strength enhancer containing a polyoxyalkylene block copolymer represented by the formula: and a cement composition containing the cement and the cement Is provided.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The alkanolamide used in the present invention
Mono-, di- or tri-C _Two-C_FourAl
Canolamine, C₁-C_FourAlkyl mono C_Two-C_FourArca
Nolamine, C₁-C_FourAlkyl di C_Two-C_FourArcano
For example, monoethanolamine.
, Diethanolamine, triethanolamine, mono
Isopropanolamine, diisopropanolamine,
Triisopropanolamine, methylethanolamine
, Methylisopropanolamine, methyldiethanol
Lamine, methyldiisopropanolamine and the like.
But the most preferred is triisopropanolamine.
(TIPA).

In the general formula (1) representing the polyoxyalkylene block copolymers used in the present invention, R ¹ and R ²
Examples of the hydrocarbon group represented by include alkyl, alkenyl, aryl, alkylaryl, aralkyl, cycloalkyl and cycloalkenyl groups having 1 to 36 carbon atoms.

Among them, examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, secondary butyl, tertiary butyl and n-butyl.
Pentyl, isopentyl, secondary pentyl, neopentyl, tertiary pentyl, n-hexyl, secondary hexyl, n-heptyl, secondary heptyl, n-octyl, 2-
Ethylhexyl, secondary octyl, n-nonyl, secondary nonyl, n-decyl, secondary decyl, n-undecyl, secondary undecyl, n-dodecyl, secondary dodecyl, n-tridecyl, isotridecyl, secondary tridecyl, n- Tetradecyl, secondary tetradecyl, n-hexadecyl, secondary hexadecyl, stearyl, icosyl, docosyl, tetracosyl, triacontyl, hexatriacontyl, 2-butyloctyl, 2-butyldecyl, 2-hexyloctyl, 2-hexyldecyl, 2- Octyl decyl, 2-hexyl decyl, 2-octyl dodecyl, 2-decyl tetradecyl, 2-dodecyl hexadecyl, 2-hexadecyl octadecyl, 2-tetradecyl octadecyl, a monomethyl branched-isostearyl group and the like can be mentioned.

Examples of the alkenyl group include vinyl, allyl, propenyl, isopropenyl, butenyl, isobutenyl, pentenyl, isopentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tetradecenyl, oleyl and the like.

The aryl, alkylaryl or aralkyl group includes, for example, phenyl, toluyl, xylyl, cumenyl, mesityl, benzyl, phenethyl, styryl, cinnamyl, benzhydryl, trityl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexyl Phenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, α-naphthyl,
β-naphthyl group and the like.

Examples of the cycloalkyl group and cycloalkenyl group include, for example, cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl, methylcyclohexyl, methylcycloheptyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, methylcyclopentenyl, methylcyclohexenyl, methylcyclohepenyl And a thenyl group. Examples of the acyl group represented by R ¹ and R ² include a fatty acid having 1 to 36 carbon atoms and an acyl group derived from an aromatic carboxylic acid, such as acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, pivalyl, lauroyl, Examples include myristoyl, palmitoyl, stearoyl, acryloyl, propioloyl, methacryloyl, crotonoyl, oleoyl, benzoyl, and the like.

Among these, excellent alkanolamides
In order to exhibit the defoaming property of¹Has 8 to 3 carbon atoms
6 alkyl, alkenyl or acyl groups are preferred.
No. R ^TwoIs preferably a hydrogen atom.

In formula (1), the alkylene groups represented by A ¹ and A ² are preferably those having 3 to 8 carbon atoms, such as propylene, butylene, pentylene, hexylene, heptylene, octylene and the like. Can be Of these, a propylene group and a butylene group are preferred.

In the general formula (1), a, b and c represent the number of moles of polyoxyalkylene added.
The range of 00 is preferable, and the range of 5 to 100 is particularly preferable because of excellent defoaming property and dispersibility. B is preferably in the range of 1 to 100, more preferably in the range of 1 to 50, and particularly preferably in the range of 2 to 30. c is preferably in the range of 1 to 300, more preferably in the range of 1 to 100, and particularly preferably in the range of 1 to 50.

The portion of (A ¹ O) _a- (EO) _b- (A ² O) _{c in} the general formula (1) is constituted by block polymerization of an alkylene oxide and ethylene oxide.

The ratio of the oxyethylene group (EO) in the compound represented by the general formula (1) is preferably 1 to 30% by weight, more preferably 1 to 20% by weight. Further, the molecular weight of the compound represented by the general formula (1) is preferably in the range of 500 to 20,000, and 1,000 to 2,000.
A range of 5,000 is most preferred.

The compounding ratio of the compound represented by the general formula (1) and the alkanolamine is as follows.
The amount of the compound (1) is preferably 5 parts by weight or more, more preferably 5 to 300 parts by weight, based on 0 parts by weight. This means that if the amount of the compound (1) is too small, the effect of reducing the air entrainment of the alkanolamine is not sufficient, and if it is too large, there is no effect just in proportion to the amount added, which means technically. Because there is no

In addition, the amount of the strength enhancer used is
0.001 part by weight or more is preferable with respect to 00 parts by weight,
0.001 to 0.5 part by weight is more preferable. If the amount is too small, the effect of increasing the strength is not sufficient. If the amount is too large, there is no effect corresponding to the amount used and there is no technical meaning. Incidentally, the strength enhancer of the present invention,
The compound can be diluted with a solvent such as water and added to the cement. In this case, the amount used is the total amount of the compound (1) and the alkanolamine.

The cement to which the strength enhancer of the present invention can be used is not particularly limited, and is a mixed cement such as ordinary Portland cement, early-strength Portland cement, moderately heated Portland cement, etc., blast furnace cement, fly ash cement, silica cement, etc. Such cements can be used as long as they are commercially available, but cements having a ferrite phase of 4% by weight or more are particularly preferable.

The strength enhancer of the present invention may further contain other known antifoaming agents, for example, mineral oil, vegetable oil, aliphatic alcohol, fatty acid, or an alkylene oxide adduct such as higher alcohol, fatty acid or alkylphenol. May be added.

As a specific method of using the strength enhancer of the present invention, for example, the following method can be mentioned. (A) It is added and used when mixing concrete or the like. (B) Used during the production of cement as a cement grinding aid or in combination with a commercially available grinding aid. (C) Used as a limestone pulverization aid or in combination with a commercially available pulverization aid when producing limestone powder as a cement admixture.

The strength enhancer of the present invention includes admixtures such as an AE agent, a high-performance water reducing agent, a high-performance AE water reducing agent, a rust inhibitor, a setting retarder, a shrinkage reducing agent, limestone powder, slag, and fly. It can be used in combination with an admixture such as ash or coal ash.

[0028]

The polyoxyalkylene block copolymers represented by the general formula (1) have a structure in which a polyethylene glycol chain is centered and a polyalkylene glycol chain such as a polypropylene glycol chain is bonded to both ends thereof. It has the property of selectively reducing only the air entrainment of an alkanolamine such as TIPA without affecting the air entrainment of an AE agent or an AE water reducing agent. In addition, compounds with this structure are less likely to be adsorbed on the solid surface of cement, aggregate, etc. in concrete, etc., and are dispersed in a higher proportion in the liquid phase. Is high.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.
In the structural formula, EO represents an oxyethylene group, PO represents an oxypropylene group, and BO represents an oxybutylene group.

Example 1 A strength enhancer was prepared by mixing a test compound in an amount shown in Table 1 with 100 parts by weight of TIPA. TIPA is 0.0125 with respect to 100 parts by weight of cement (normal Portland cement manufactured by Taiheiyo Cement Co.)
It was added so as to be parts by weight and pulverized to produce a cement.
For comparison, a cement containing no strength enhancer was also produced.

[0031]

[Table 1]

Note 1) The content of the test compound was expressed as parts by weight based on 100 parts by weight of TIPA. Note 2) Comparative Example L contains only TIPA. Note 3) Type of test compound DF-1: RO (BO) 17 (EO) 6 (PO) 3.5 -H (R: C 18 H 37 -, C 20 H 41 -,
C ₂₂ H ₄₅ - mixtures) DF-2: RO (PO ) 35 (EO) 5 (PO) 5 -H (R: 2- octyl _{decyl) DF-3: C 18 H} 37 O (PO) 30 ( EO) ₅ (PO) ₅ -H DF-4: C ₁₇ H ₃₅ COO (PO) ₃₀ (EO) ₁₈ (PO) ₁₅ -H DF-5: C ₁₈ H ₃₇ O (PO) ₁₅ (EO) ₅ ( PO) ₁₅ -H DF-6: FS- Anti-Home 90 (silicone-based defoamer) manufactured by Dow Chemical Company DF-7: Dyna Fresia G-9 (mineral oil-based) manufactured by Idemitsu Kosan Co., Ltd.

Next, the cement in the concrete composition shown in Table 2 was used as the cement manufactured as described above, and the other cements were manufactured according to the composition shown in Table 2, and the amount of air immediately after mixing was determined.
The compressive strength of 7 days and 28 days of material age was measured. Table 3 shows the measurement results. The target air amount is within a range of ± 1.5% [air amount of concrete in Table 2 containing no strength enhancer ("none" in Comparative Example in Table 3)].

[0034]

[Table 2]

[0035]

[Table 3]

As shown in Table 3, the air amount of the concrete manufactured using the cement composition containing the strength enhancer of Examples A to I was all the above-mentioned target air amount of 4.6 ± 1.
While satisfying 5%, that is, 3.1 to 6.1%,
The compressive strength is improved by about 20% at both the age of 7 days and 28 days as compared with cement concrete containing no strength enhancer. On the other hand, the air amount of the concrete manufactured using the cement composition containing the strength enhancer of Comparative Example J-L greatly exceeds the target air amount. Also,
The compressive strengths of these comparative examples J to L are the same as those of the examples.
Despite the presence of PA, it is only about the same level as concrete using a cement containing no strength enhancer ("none" in Comparative Example), and the original strength enhancement effect of TIPA is a decrease in strength due to an increase in air volume. Have been offset.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sho Sano 2-4-2, Daisaku, Sakura-shi, Chiba Pref. Inside the Sakura Research Laboratory, Pacific Cement Co., Ltd. Asahi Denka Kogyo Co., Ltd. (72) Inventor Nobuyuki Shimamura 7-35 Higashiogu, Arakawa-ku, Tokyo Asahi Denka Kogyo Co., Ltd.

Claims (3)

[Claims] An alkanolamine and a compound represented by the following general formula (1): R ¹ O— (A ¹ O) _a — (EO) _b — (A ² O) _c —R ² (1) R ¹ represents a hydrocarbon group or an acyl group, R ² represents a hydrogen atom, a hydrocarbon group or an acyl group, a ¹ and a
² represents an alkylene group having 3 or more carbon atoms, E represents an ethylene group, and a, b, and c each represent a number of 1 or more.] Strength enhancement for cement containing a polyoxyalkylene block copolymer represented by the formula: Agent. 2. The strength enhancer for cement according to claim 1, wherein the alkanolamine is triisopropanolamine. 3. A cement composition comprising the strength enhancer according to claim 1 and cement.