JPH0645492B2 - Admixture for concrete and mortar - Google Patents

Description

The present invention relates to an admixture for concrete, and more specifically, to prevent freezing damage such as crack collapse by repeated action of freezing and thawing caused by changes in temperature of hardened concrete. It relates to an AE agent used for the purpose of producing concrete or mortar in which bubbles are entrained in concrete.

Widely known AE agents include anionic surfactants such as natural resin salts, alkyl sulfates, and alkylallyl sulfonates, or nonionic surfactants such as polyoxyethylene alkylaryl ethers. It has been known. Its action is that it is adsorbed at the interface between air and water in the gaps between cement particles and fine aggregates, and its surface-active action causes fine closed cells to be evenly distributed in the concrete, and imparts fluidity by the bearing effect of the bubbles. Improves workability, and when subjected to frost damage such as road surface pavement in cold regions, the fine closed cells distributed in the concrete alleviate the large volume expansion pressure caused by freezing of free water, and resist cracking and destruction of concrete. To impart sex.

However, it is well known that conventionally used AE agents have considerably different sizes of entrained bubbles or distribution states of bubbles depending on the type. That is, the resin acid salt system can obtain fine closed cells, but cannot be used for water having a high hardness and lacking hard water resistance. Anion type such as alkyl sulphate has soft air bubbles, and non-ionic type has large foam particle size, so that foam stability is poor and effect as AE agent is small. ing. Therefore, it is the current situation that they are used properly depending on the usage conditions.

The inventors of the present invention have found that the surfactant of the present invention has excellent performance as an AE agent as a result of intensive studies to solve the above-mentioned drawbacks.

That is, the present invention is (1) the following general formula (However, A represents a polyhydric alcohol residue having 3 to 6 OH groups, and R represents a higher fatty acid residue having 6 to 22 carbon atoms.

1 + m + n is an integer of 1 to 100, and X and Z are 1 to
An integer of 5, Y is 0 or an integer of 1 to 4, and X,
It is shown that the total number of Y and Z corresponds to the number of OH groups possessed by A. Further, M represents an alcal metal, ammonium, or N-alkyl (or alkanol) ammonium having 6 or less carbon atoms. And an admixture for concrete and mortar.

(2) The admixture according to claim (1), wherein A is a sorbit residue in the general formula.

(3) The admixture according to claims (1) and (2), wherein R in the general formula is an oleic acid residue.

(4) In the general formula, 1 + m + n is an integer of 30 to 60, and relates to the admixture according to claims (1), (2) and (3).

The compound of the present invention can be easily obtained by a known method. That is, polyhydric alcohols, for example, polyhydric alcohols selected from glycerin, pentaerythritol, diglycerin, arabite, sorbit, mannite, dipentaerythritol and the like are treated with an alkali hydroxide catalyst to give ethylene oxide (hereinafter referred to as EO). Addition reaction and then acid or alkali catalyst is used to select higher fatty acid such as caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, oleic acid, stearic acid and behenic acid. A partial esterification reaction with a higher fatty acid may be carried out, and the remaining OH groups may be sulfated with an equivalent amount of a sulfating agent such as sulfuric acid, chlorosulfonic acid, sulfuric acid anhydride, sulfamic acid and the like.

However, from the viewpoint of economy and usefulness, it is preferable that the polyhydric alcohol is sorbit and the addition amount of EO is 30 to 60 mol, and the fatty acid is oleic acid. Alternatively, sulfamic acid is preferable as the sulfating agent, and the other is susceptible to hydrolysis of the ester bond portion, so care must be taken.

The compound in the present invention is an excellent AE agent having a fine foaming property and a foam lasting property even when used alone, but also other cement admixtures such as a cement dispersant and a high-performance water reducing agent. Etc., the function as an AE agent is not impaired even when used in combination or in a mixture.

Hereinafter, the cement admixture according to the present invention will be described with reference to Examples, but the present invention is not limited thereto.

〔Example〕

Compound Production Example 1 182 parts (1 mol) of sorbit was charged into a pressure reaction kettle, and 0.5 part of caustic potash was added as a catalyst, 110 to 120 ° C.
After dehydration for 1 hour, the reaction kettle is replaced with nitrogen.

Next, after reacting 1760 parts (40 mol) of EO at a pressure of ^{2 to 3} kg / cm ² and a temperature of 145 to 150 ° C., the reaction temperature is about 1
Mature for hours.

The reaction product was placed in a four-necked flask, and 846 parts (3 mols) of oleic acid and 7 parts of caustic potash were added, and dehydration reaction was carried out at 220 to 230 ° C. for about 5 hours to obtain an esterified product having a reaction rate of 95% or more. This was cooled to 130 ° C., 219 parts (3 mol) of sulfamic acid and 180 urea as a catalyst.
Part (3 mol) was charged, and the mixture was sulfated at the same temperature for 2 hours and then adjusted to pH 7 to 8 with aqueous ammonia to obtain the admixture (compound (1)) of the present invention.

Compound Production Examples 2 to 4 The synthesis conditions for the admixture of the present invention (Compound Production Examples (2) to (4)) produced according to Compound Production Example 1 are summarized in Table 1. The admixture of the present invention (Compound Production Example (1)-
(4)) is used for the tests of Examples 1 to 3.

Example 1 In order to confirm hard water resistance, 50 ° dH, 100 ° dH, 2
To 100 g of each hard water of 00 ° dH, 0.5 g of the admixture,
And 0.1 g were added, and the solubility was observed. The results are shown in Table-2.
Note.

As is clear from Table 2, it was confirmed that the admixture of the present invention was superior in hard water resistance to the resin acid-based admixture.

Example 2 400 g of ordinary Portland cement in a mortar mixer
And 1200g of fine aggregate (Toyoura standard sand) was put in, and after mixing for 1 minute at low speed, 240g of water in which 0.02g of admixture was dissolved
Table 3 shows the results of measuring the stability of bubbles in a mortar obtained by adding and kneading for 3 minutes.

From Table 3, it was confirmed that the admixture of the present invention possesses a foam that is stable for a long time, as compared with generally marketed anionic and nonionic admixtures.

Example 3 The results of measuring the air entrainment to concrete and the slump compressive strength of the following materials by the following measuring methods are shown in Table-4.

Material Cement ...... Normal Portland cement (specific gravity 3.1)
6) Fine aggregate …… River sand (specific gravity 2.61) Coarse aggregate …… River gravel (specific gravity 2.63) Measurement method Slump JIS A 1101 Air volume JIS A 1128 Compressive strength JIS A 1108 As is clear from Table 4, the admixture according to the present invention is superior to the admixture on the market even at a low addition amount.

Claims (4)

[Claims] 1. The following general formula (However, A represents a polyhydric alcohol residue having 3 to 6 OH groups, and R represents a higher fatty acid residue having 6 to 22 carbon atoms.
+ M + n is an integer of 1 to 100, and X and Z are 1 to 5
, Y is 0 or an integer of 1 to 4 and X, Y,
It is shown that the total number of Z corresponds to the number of OH groups possessed by A. M is an admixture for concrete and mortar, which contains an alkali metal, ammonium, or N-alkyl (or alkanol) ammonium having 6 or less carbon atoms). 2. The admixture according to claim 1, wherein A in the general formula is a sorbit residue. 3. The admixture according to claims (1) and (2), wherein R in the general formula is an oleic acid residue. 4. The admixture according to claims (1), (2) and (3), wherein 1 + m + n in the general formula is an integer of 30 to 60.