Low air leading reducing type polycarboxylic acid concrete water reducer and preparation method thereof

Abstract

The invention relates to a low air leading reducing type polycarboxylic acid concrete water reducer and a preparation method thereof. The water reducer is formed by a single body A and a single body B in copolymerization according to the molar ratio of 1:3-3.5. The single body A is modified polyether TPEG, and the single body B is one or several of crylic acid, methyl acrylate, acrylamide, methacrylic acid, methyl methacrylate and methacrylamide. The preparation method includes first adding H2O2 into modified polyether TPEG water solution under the temperature of 50-55 DEG C, stirring the mixture for 10-15min, simultaneously dropping mixed water solution of ascorbic acid and a chain transfer agent and single body B solution respectively and continuously conducting reaction for 0.5-1.0 hour in heat insulation mode after dropping is finished to obtain the polycarboxylic acid water reducer after pH value adjustment. The water reducer has higher water reducing rate, has low air content and a certain reducing function if used for concrete and is the multifunctional high-efficiency water reducer integrating water reducing, reducing and low air leading.

Description

technical field [0001] The invention belongs to the field of polycarboxylate concrete water-reducer, in particular to a low-air-entraining and shrinkage-reducing polycarboxylate concrete water-reducer and a preparation method thereof. Background technique [0002] Cracking of concrete due to shrinkage can lead to greatly reduced strength and durability of concrete, thereby further shortening the service life of concrete. The shrinkage and cracking of concrete, especially high-performance concrete, has attracted great attention from the engineering community. Although polycarboxylate water reducers can reduce the shrinkage of concrete to a certain extent, it is still difficult to meet the needs of the project. At the same time, polycarboxylate water reducers The high air content of the polycarboxylate superplasticizer also seriously affects the strength of the concrete, so reducing the shrinkage of the concrete and reducing the air content of the polycarboxylate superplastici...

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Problems solved by technology

Although the use of these shrinkage reducing agents reduces the shrinkage of concrete to a certain extent, the engineering cost is greatly increased, and the synthesis process is complicated

[0004] For the problem of high gas content of polycarboxylate superplasticizer, it is mainly solved by adding a certain amount of defoamer such as siloxane polymer. Although defoamer can significantly reduce the gas content of polycarboxylate superplasticizer, but There is a problem of difficult compatibility. As the storage time prolongs, the defoamer compounded in the polycarboxylate water reducer will precipitate in the form of oil droplets. Although there is no compatibility problem with the foam group, it is expensive and its defoaming ability is reduced compared with compounding

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