JPH0678185B2 - Durability improver for cement hydraulic products - Google Patents

Description

TECHNICAL FIELD The present invention relates to a durability improver for cement hydraulic products, and more specifically to a compound represented by the general formula (I): [Wherein R ¹ and R ² are each a hydrogen atom or an alkyl group, X is a group represented by the formula —CH ₂ CH ₂ O—, and Y is a group represented by the formula —CH ₂ CH (CH
Group or the formula -CH (CH ₃₎ CH ₂ O- a group represented indicated by ₃₎ O-, m is 0 or an integer from 1 to 4, n represents an integer of 1 or more, is and m + n 1 Each means an integer of ~ 30, X
And Y are bonded in any order]] to a durability improver for cement hydraulic cement containing one or more compounds represented by the formula [1].

Conventional technology: Traditionally, the life of reinforced concrete structures is 50 to 60 years.
It has been considered about a year. This life is generally such that, for example, the carbonization of concrete progresses from the surface of concrete, that is, the cement paste in concrete has a pH of 12 to 12 mainly due to calcium hydroxide and alkali hydroxide (sodium hydroxide, potassium hydroxide, etc.). Although it has a strong basicity of 13, calcium hydroxide is easily neutralized by contact with carbon dioxide in the presence of water, and when this neutralized region reaches the position of the reinforcing bar, the reinforcing bar rusts. , Reinforced concrete members lose their proof strength. In addition, as a factor that impairs the durability of reinforced concrete structures, substances such as salts and acids having a property of corroding iron or substances that induce corrosion enter the concrete to corrode the reinforcing bar. As a measure that has been conventionally taken as a means for improving the durability of a reinforced concrete structure and extending its life, (1) increase the cover thickness of the concrete to the reinforcing bar.

(2) Reduce the water-cement ratio of concrete.

(3) A finishing material having excellent airtightness is applied to the concrete surface.

And so on.

Problems to be Solved by the Invention: Although these conventional measures are effective in preventing significant deterioration of concrete, they are not effective enough to significantly extend the life of reinforced concrete.

In particular, when trying to suppress the neutralization by the finishing material, the effect was recognized in the short term, but the durability of the finishing material itself became a problem, and there was a problem that it could not be said to be a highly reliable method. .

Means for Solving the Problems: As a result of earnest studies for solving the above problems, the inventors of the present invention have found that when the compound represented by the general formula (I) is added to a cement hydraulic material, the cement hydraulic material is used. Obtained a new finding that the neutralization of the material is suppressed, the permeability of the cement hydraulic material is also reduced, and the penetration of chloride ions is also suppressed, and thus the durability of the cement hydraulic material is improved, Completed this invention.

The present invention is a durability improver for cement hydraulic fluid containing one or more compounds represented by the general formula (I), and as an example of the alkyl group in R in the general formula (I), Examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tertiary butyl, n-pentyl, isopentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, and the like. Alkyl groups having from 1 to 12 carbon atoms are preferable, and alkyl groups having 1 to 9 carbon atoms are particularly preferable.

Further, in the general formula (I), X meaning a group represented by the formula —CH ₂ CH ₂ O— and a group represented by the formula —CH ₂ CH (CH ₃ ) O— or the formula —CH (CH ₃ ) CH. Y, which means a group represented by ₂ O-, is bonded in any order. That is,-(X) _m (Y) _n-
Indicates the residue of a single adduct of ethylene oxide or propylene oxide and a polymer, or a block polymer or a random polymer.

Further, as described above, m in the general formula (I) is 0 or an integer of 1 to 4, n is an integer of 1 or more, and m
+ N means an integer of 1 to 30, but a compound when m + n exceeds 30 is not preferable because it lowers the strength of the cement hydraulic material.

The compound represented by the general formula (I) is a known compound obtained by reacting, for example, phenol or alkylphenol with a monomer or polymer of ethylene oxide and / or propylene oxide.

Next, among the compounds represented by the general formula (I), typical compounds and production examples thereof will be shown.

Production Example 1 282 g of phenol and 1.4 g of sodium hydroxide as a catalyst were placed in a 1-volume autoclave, while introducing nitrogen gas,
The temperature is gradually raised and dehydration is performed at 100 to 110 ° C for about 30 minutes. After sealing, 522 g of propylene oxide was pressure-fitted at a temperature of 100 to 160 ° C., the addition reaction was carried out for about 3 hours, and further aged at the same temperature for 30 minutes. It is then cooled, opened, neutralized and purified to give 765 g of a mixture of compound 1 and compound 2 (95: 5) as a pale yellow liquid.

Production Example 2 By the same method as in Production Example 1, 216 g of a mixture of meta-cresol and para-cresol (60:40), 1.1 g of sodium hydroxide and 696 g of propylene oxide were used, and a mixture of compound 3 and compound 4 (96: 4) 832 g. To get

Production Example 3 By the same method as in Production Example 1, 2,4-dimethylphenol 80 g, 2,5-dimethylphenol 80 g, 3,5-dimethylphenol 80 g, sodium hydroxide 1.2 g, propylene oxide 6
85 g of a mixture of compound 5 and compound 6 (96: 4) 855
get g.

Production Example 4 330 g of p-nonylphenol and 1.7 g of sodium hydroxide as a catalyst were placed in a 1-volume autoclave, and the temperature was gradually raised while introducing nitrogen gas, and dehydration was carried out at 100 to 110 ° C. for about 30 minutes. After sealing, add 435 g of propylene oxide to a temperature of 100-1.
The mixture is pressed into 60 ° C., the addition reaction is carried out for about 3 hours, and the mixture is aged at the same temperature for 30 minutes. It is then cooled, opened, neutralized and purified to give 708 g of a mixture of compounds 7 and 8 (96: 4) as a pale yellow liquid.

Production Example 5 p-Nonylphenol 25 was prepared in the same manner as in Production Example 4.
Using 0 g, 1.3 g of sodium hydroxide and 593 g of propylene oxide, 778 g of a mixture of compounds 9 and 10 (95: 5) is obtained.

The method for adding the durability improver of the cement hydraulic material of the present invention to the cement hydraulic material (kneaded material containing cement, which is a hydraulic material such as cement paste, grout, mortar and concrete, as a hardening component) is a conventional method. . That is, it may be added to the kneading water, or may be added to the cement hydraulic material once kneaded. Alternatively, the cement hydraulic material may be added after it arrives at the site by a truck mixer truck. Which addition method is adopted may be determined according to the kind of the compound represented by the general formula (I), the conditions of the structure, and the like.

Further, the amount of the compound represented by the general formula (I) added to the cement hydraulic material is 0.1 to 8%, preferably 1 to 6% (% by weight relative to cement).

The durability improver for cement hydraulic products of the present invention is not limited by the type of cement, the type of aggregate, the admixture used in combination, and the admixture material. That is, as the type of cement,
Common commercially available cements such as ordinary Portland cement, early strength cement, moderate heat cement, blast furnace cement and fly ash cement can be mentioned, and part of them is replaced with fly ash, granulated slag powder, siliceous mixture, etc. In some cases, this substitution may advantageously achieve the object of the present invention.

Further, it can be used in combination with a water reducing agent for cement hydraulic material, a swelling agent and other known admixture materials for concrete or mortar.

EFFECTS OF THE INVENTION, Examples: When a durability improver for a cement hydraulic material containing one or more compounds represented by the general formula (I) of the present invention is added to the cement hydraulic material, the cement hydraulic material is added. Neutralization of cement hydraulic material is suppressed without adversely affecting the compressive strength of the material, water permeability is also reduced, and invasion of chlorine ions is also suppressed. Therefore, durability of cement hydraulic material is improved. To be done. Furthermore, since the compound represented by the general formula (I) has an effect of reducing the water permeability of the cement hydraulic material, the cement hydraulic material to which the compound represented by the general formula (I) is added has a high hydraulic pressure or Suitable for concrete structures subject to atmospheric pressure (eg offshore concrete structures, dams, LNG tanks, etc.).

Next, the effects and embodiments of the present invention will be described with reference to test examples.

Test Example 1 (Neutralization test in mortar) For the mortar having the formulation shown in Table 1, the following second
The compound represented by the general formula (I) shown in the table was added to the weight of cement at the following predetermined concentrations (the compound was not added to plain). The addition was carried out by mixing in kneading water.

After curing for 24 hours in a 4 cm × 4 cm × 16 cm rectangular parallelepiped form,
After curing for up to 2 weeks in a humid atmosphere at 20 ° C, 1 week for 20
It was dried under the conditions of ° C and 60% RH. These specimens were placed in a tank having a temperature of 30 ° C., a humidity of 60% RH and a carbon dioxide gas concentration of 5%, and left in this tank for a predetermined period. This test accelerates the neutralization of mortar by carbon dioxide.

After standing for a predetermined period of time, each sample was taken out from the tank, the sample was divided around the center, and an ethyl alcohol solution of phenolphthalein (concentration 1%) was sprayed on the cracked surface. The surface of the mortar remains alkaline, the surface turns red, and the neutralized part does not change the surface. The neutralization depth of the surface was measured by this method.

The measurement results are shown in Table 2.

Test Example 2 (Neutralization Test on Concrete) Concrete having a mixture shown in Table 3 was 10 cm × 10 cm ×
It was placed in a 40 cm rectangular parallelepiped mold and an experiment was conducted under the same conditions as in Test Example 1 below to measure the neutralization depth of the concrete surface. The measurement results are shown in Table 4.

Fine aggregate: Oigawa river specific gravity 2.62, coarse grain ratio FM2.80 Coarse aggregate: Oigawa gravel specific gravity 2.66, coarse grain ratio FM6.86 Cement: Sumitomo Ordinary Portland Cement Specific gravity 3.16 Test Example 3 (Concrete Water Permeability Test) Concrete prepared in the same manner as in Test Example 2 [a plain, 2% and 4% of a mixture of compounds 1 and 2 (95: 5) obtained in Production Example 1 were added, respectively] Concrete and concrete containing 0.25% of a lignin-based AE water reducing agent] were aged for 24 hours in the same mold as in Test Example 2, and then aged for 14 days in water at 20 ° C. Then
After drying under conditions of 20 ° C. and 60% RH for 7 days, each concrete was subjected to a water permeability test. According to the input method, the permeability test determines the diffusion coefficient (permeability coefficient) of the penetration depth of water when a constant water pressure of 10 kg / cm ^{2 is applied} to the bottom surface of a cylinder specimen with a diameter of 150 mm and a height of 150 mm for 48 hours. It was calculated. The results are shown in Table 5.

Test Example 4 (chlorine ion penetration test in mortar) A compound of the present invention was added to a mortar prepared under the same conditions as in Test Example 1 at a predetermined concentration to knead the mortar,
Cured in a 24-hour formwork. 14 days thereafter, 20 ℃, 100% R
After curing under the condition of H, it was dried for 7 days under the conditions of 20 ° C. and 60% RH, and then immersed in a saturated sodium chloride aqueous solution for 14 days. After completion of the immersion, each specimen was divided near the center, and a 0.1% sodium fluorescein aqueous solution and a 0.1N silver nitrate aqueous solution were sprayed on the cracked surface.
As the chlorine ion invades, it changes color,
By this method, the depth of penetration of chloride ions was measured.
The results are shown in Table 6.

Test Example 5 (chlorine ion penetration test in concrete) Concrete prepared in the same manner as in Test Example 2 [a plain, 2% and 4% of a mixture (95: 5) of compounds 1 and 2 obtained in Production Example 1 respectively] The added concrete and the concrete containing 0.25% of the lignin-based AE water reducing agent were cured and dried under the same conditions as in the mortar of Test Example 4, and the same chlorine ion as in the case of the mortar of Test Example 4 was added. A penetration test was performed. The results are shown in Table 7.

As is clear from the above test examples, the above general formula (I)
The rate of neutralization of the cement hydraulic material to which the compound shown in is added is slower than that of the one without addition, the water permeability is low, and the penetration degree of chloride ion is slow. Therefore, it is possible to suppress the corrosion of iron by reducing the corrosion of iron by suppressing neutralization in cement hydraulic materials, for example, reinforced concrete, or by reducing the penetration of harmful substances such as salt, and thus the life of reinforced concrete structures. Can be significantly extended.

Front page continued (72) Inventor Toshiharu Urano 2-5-14 Minamisuna, Koto-ku, Tokyo Inside Takenaka Corporation Technical Research Institute (72) Inventor Kyoichi Tanaka 5-6-1 Matsushiro, Yatabe-cho, Tsukuba-gun, Ibaraki Prefecture (72) Inventor Masa Sugiyama 3-7-1 Ninomiya, Yatabe-cho, Tsukuba-gun, Ibaraki Prefecture (72) Inventor Shuzo Endo 6-57-15 Minamisenju, Arakawa-ku, Tokyo (72) Inventor Keisuke Fujioka Miyamae, Kawasaki-shi, Kanagawa 3-9-7 Kumiyamae (56) Reference JP-A-59-232952 (JP, A) JP-A-62-91449 (JP, A) JP-A-62-91452 (JP, A) JP-A-62- 246852 (JP, A)

Claims (1)

[Claims] 1. A general formula [Wherein R ¹ and R ² are each a hydrogen atom or an alkyl group, X is a group represented by the formula —CH ₂ CH ₂ O—, and Y is a group represented by the formula —CH ₂ CH (CH
Group or the formula -CH (CH ₃₎ CH ₂ O- a group represented indicated by ₃₎ O-, m is 0 or an integer from 1 to 4, n represents an integer of 1 or more, is and m + n 1 Each means an integer of ~ 30, X
And Y are bonded in any order]], a neutralization inhibitor, a water permeability reducing agent or chlorine of a cement hydraulic material, characterized by containing one or more of the compounds represented by Ion penetration inhibitor.