JPS6144827B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to plasticizers for concrete or mortar. In order to reduce cracks and improve the durability of concrete structures, it is essential to densely pour hard-mixed concrete with a small unit water volume. However, in recent years, the spread of concrete pumps and the decline in the quality of aggregate have forced concrete to become richer and softer, which is a factor that directly or indirectly promotes the occurrence of cracks. Additionally, building structures in Japan generally have small cross-sectional dimensions and a large amount of reinforcement, making it difficult to place hard-mixed concrete densely. Therefore, there is a strong demand for a fluidizing agent for concrete or mortar that can be added during or after mixing relatively hard concrete or mortar with a small unit amount of water to increase fluidity. relates to a fluidizing agent for concrete or mortar that meets these requirements. Currently, in the field of civil engineering and construction, hard-mixed ready-mixed concrete mixed in a ready-mixed concrete plant is mixed with a fluidizing agent on-site, agitated, and poured using a concrete pump. The admixtures used at this time include high performance water reducing agents such as melamine resin sulfonate or β-naphthalene sulfonate formalin condensate, and alkylaryl sulfonate and polyester to maintain the required amount of air in the concrete. A mixture of oxyethylene alkyl ether sulfate salt, polyoxyethylene alkyl allyl ether sulfate salt, polyoxyethylene alkyl ether-based nonionic activator, and air volume regulating foaming agent such as natural resin acid salt is used. There is. In general, the properties that such a fluidizing agent for concrete or mortar should have include, of course, having a large fluidizing effect, but also that the amount of air before and after fluidization and before and after pumping is stable, and that there is no need for excessive fluidization. Examples include not causing bleeding, not exhibiting abnormal setting acceleration or retarding effects, not causing a decrease in strength, and not impairing durability, particularly freeze-thaw resistance. However, the above-mentioned fluidizing agents that have been used so far have large fluctuations in the amount of air in the concrete or mortar before and after fluidization or before and after pumping. The amount of air varies depending on the type of water reducing agent, so the only solution was to adjust the blending ratio of the fluidizing agent and air amount adjusting foaming agent added to the base concrete.
If the air volume fluctuates too much, it will cause a decrease in strength, and if the air volume decreases due to foam breakage, it will cause excessive bleeding, which will have a large negative impact on freeze-thaw resistance, and sometimes lead to a decrease in durability. It becomes a factor. The object of the present invention is to provide a plasticizer for concrete or mortar that does not have these drawbacks. The fluidizing agent for concrete or mortar of the present invention contains a naphthalene sulfonate formalin condensate () and a maleated natural resinate (). Naphthalene sulfonate formalin condensate () is 30 mol% naphthalene alone or with it
It is preferable to use an alkali metal salt or calcium salt of a sulfonated product having a sulfonation rate of 95 to 135%, preferably 105 to 125% in a mixture with the following alkylnaphthalene. The maleated natural resin acid salt () is preferably an alkali metal salt of maleated natural resin acid with a maleation rate of 3 to 13% by weight, and examples of the natural resin acid include abietic acid, neoabietic acid, pimaric acid. , levopimaric acid, dextropimaric acid, isopimaric acid, parastric acid, and mixtures thereof may be used. The ratio between component () and component () is by weight
The ratio is preferably 100:0.5 to 100:5. The fluidizing agent of the present invention is generally used by adding 0.05% to 1.2% as an active ingredient based on the weight of cement. If the maleation rate of component () is less than 3% by weight, the compatibility with component () will be poor, resulting in a lack of product stability and separation phenomenon, and if the maleation rate exceeds 13% by weight, concrete will deteriorate. Alternatively, the diameter of the bubbles in the mortar becomes large, the air content becomes unstable, the bubbles become discontinuous, and the freeze-thaw resistance decreases, which is not preferable. If the ratio of component () to 100 parts by weight is less than 0.5 parts by weight, it will be difficult to maintain the required amount of air in concrete or mortar, and if it is more than 5 parts by weight, the amount of entrained air will be excessive and unstable. , is undesirable because of its reduced strength and lack of freeze-thaw resistance. The fluidizing agent of the present invention includes portland cement,
It can be used in concrete and mortar containing various cements such as fly ash cement, special cement and mixed cement. Methods for adding the fluidizer of the present invention to concrete or mortar include adding the fluidizer of the present invention as an aqueous solution or dry powder at the same time as concrete or mortar is mixed, or adding the fluidizer after mixing concrete or mortar. You can also knead it evenly. The plasticizer for concrete or mortar of the present invention has good air volume stability before and after addition of the plasticizer and before and after pumping, regardless of the type of admixture in the base concrete, and has low material separation resistance. It has excellent properties such as hardness, freeze-thaw resistance, and other general properties required of this type of fluidizing agent. The present invention will be explained in more detail with reference to Examples below. Example Manufacture of naphthalene sulfonate formalin condensate (NSF) NSF-A Sulfonation is carried out by a conventional method using 1.7 mol of 98% sulfuric acid per 1 mol of naphthalene, and water is added to the obtained sulfonated product. , 37% under sulfuric acid
0.82 mol of formalin is added dropwise and a condensation reaction is carried out by a conventional method. The condensation product was neutralized with calcium hydroxide, filtered for desalting, and replaced with sodium carbonate to obtain a sodium salt of naphthalenesulfonic acid formalin condensate (solid content: 40%) with a sulfonation rate of 119%. NSF-B A mixture of 0.8 mol of naphthalene and 0.2 mol of methylnaphthalene is sulfonated using 1.5 mol of 98% sulfuric acid in a conventional manner, and then NSF-A
Under the same conditions as above, 0.92 mol of 37% formalin was added dropwise to carry out the condensation reaction, and the mixture was neutralized with calcium hydroxide.
After cooling, by-product gypsum was removed by filtration to obtain () with a sulfonation rate of 111% and a solid content of 42%. Production of maleated natural resinate (MR) MR-1 Abietic acid 44% by weight Neoabietic acid 12 〃 Pimaric acid 10 〃 Isopimaric acid 13 〃 Parastophosphoric acid 21 〃 1 mol of natural resin acid mixture having a composition of 100% by weight or more 0.11 mol of maleic anhydride was subjected to an addition reaction in a xylene solvent at 130 to 140°C for 3 hours by a conventional method, and after removing the solvent, it was saponified with potassium hydroxide to give a maleation rate of 3.4% by weight and solid content. 50% potassium maleated resinate was obtained. MR-2 Maleic anhydride per mole of abietic acid
Addition reaction of 0.18 mol with MR-1 under the same conditions,
Sodium maleate resinate was obtained with a maleation rate of 5.3% by weight and a solid content of 30%. MR-3 Abietic acid 53% by weight Neoabietic acid 8 〃 Pimaric acid 8 〃 Isopimaric acid 14 〃 Parastric acid 17 〃 0.35 mol of maleic anhydride is added by conventional method to 1 mol of a natural resin acid mixture having a composition of 100% by weight or more. by 170
Addition reaction was carried out at ℃ for 5 hours, and the maleation rate was determined by neutralization.
Potassium maleate resinate was obtained with a solid content of 10.6% by weight and a solid content of 50%. MR-4 For 1 mole of natural resin acid used in MR-1,
Using 0.05 mol of maleic anhydride, it was reacted under the same conditions as MR-1 to obtain a maleated resin acid sodium salt having a maleation rate of 1.4% by weight and a solid content of 30%. MR-5 For 1 mole of natural resin acid used in MR-3,
Using 0.54 mol of maleic anhydride, it was reacted under the same conditions as MR-3 to obtain a maleated resin acid triethanolamine salt with a maleation rate of 16.5% by weight and a solid content of 30%. Preparation of base concrete The base concrete shown in Table 1 was prepared.

[Table] Superplasticizer performance test Table 2
A predetermined amount of the fluidizing agent shown in was added to evaluate the concrete performance. The fluidizing agent was added after mixing the base concrete in Experiment Nos. 1, 4, 5, 7, 8, and 9, and was added during mixing in the other cases. The results obtained are shown in Table 2.

[Table] Concrete test method Slump: According to JIS A 1101. Air amount: According to JIS A 1128. Freeze-thaw resistance: According to ASTM C-666. As is clear from Table 2, Experiment No. 1 and No. 4
In No. 2 and No. 3, fluidizer was added after mixing the base concrete, and in No. 2 and No. 3, fluidizer was added during mixing, but in both cases, the fluctuations in slump and air volume after pumping were extremely small compared to after addition. Moreover, the freeze-thaw resistance is 97% or more in terms of relative elastic modulus (300 cycles), indicating that the resistance is extremely high and the durability is good. On the other hand, Experiment No. 9 is a comparative example of NSF-A.
is used alone, but by adding it, the amount of air decreases significantly and the freeze-thaw resistance is inferior. In Experiments No. 5 and No. 6, the maleation rate of MR was within a preferable range, so there was no slump or slump after pumping.
This shows that the decrease in air amount is relatively large and the durability is poor, which is not preferable. In Experiment No. 7, the mixing ratio of NSF and MR was outside the preferred range, so the amount of air entrained was large, and even after pumping, the air amount was maintained at 4%, but the bubble diameter was large and it was discontinuous. This indicates that the durability is inferior. Experiment No. 8 is a comparative example in which a normal AE agent is blended with NSF, but the freeze-thaw resistance is poor, indicating that it is unsuitable as a fluidizing agent.

Claims (1)

[Claims] 1 Naphthalene sulfonate formalin condensate 1
and a maleated natural resinate ().A fluidizing agent for concrete or mortar. 2 Naphthalene sulfonate formalin condensate () is 30 mol% naphthalene alone or together with it.
The fluidizing agent according to claim 1, which is an alkali metal salt or calcium salt of a sulfonated product having a sulfonation rate of 95 to 138% in a mixture with the following alkylnaphthalene. 3. The fluidizing agent according to claim 1, wherein the maleated natural resin acid salt () is an alkali metal salt of a maleated natural resin acid having a maleation rate of 3 to 13% by weight. 4. The natural resin acid of the maleated natural resinate () is abietic acid, neoabietic acid, parastric acid, pimaric acid, levopimaric acid, dextropimaric acid, isopimaric acid or a mixture thereof. Superplasticizer. 5. The fluidizing agent according to claim 1, wherein the ratio of naphthalene sulfonic acid formalin condensate () to maleated natural resinate () is from 100:0.5 to 100:5 by weight.