A viscosity-reducing polycarboxylate water reducer containing an alkyl group, its preparation method and use

Abstract

The invention provides a viscosity-reducing active macromonomer, and the invention also provides a viscosity-reducing polycarboxylate water-reducer. The viscosity-reducing polycarboxylate water-reducer synthesized by the invention has a Each functional group interacts synergistically. Compared with the viscosity-reducing polycarboxylate superplasticizer synthesized by the prior art, the viscosity-reducing effect is superior and the water-reducing rate is not affected. At the same time, due to the introduction of a large amount of hydrophobicity in the PEG side chain Alkyl group reduces the HLB value, enhances the surface active effect, and has good shrinkage reduction performance. The concrete mixed with the product of the invention has low shrinkage and no cracking. The viscosity-reducing hydrophobic functional group is located on the side chain, and the viscosity-reducing effect of the water reducer can be adjusted through the content of the viscosity-reducing functional group, but it does not affect the content of the dispersing group and the dispersion effect on cement particles, so it does not affect the water reducing effect. agent dispersion and water reducing effect.

Description

technical field [0001] The invention relates to the technical field of concrete admixtures, in particular to a viscosity-reducing polycarboxylate water reducer containing an alkyl group, a preparation method and application thereof. Background technique [0002] In recent years, with the increase of my country's infrastructure construction, high-grade concrete is gradually entering the building material market due to its high strength, good integrity and low weight, especially in bridge engineering. However, due to the use of a large amount of gel material and low water-binder ratio, high-grade concrete has the problems of high viscosity and slow flow speed, which in turn causes problems in concrete mixing, transportation, pumping and construction, which largely limits high-strength super Promotion and application of high-strength concrete. [0003] For engineers and technicians, the high-strength ultra-high-strength concrete viscosity problem is a long-standing technical p...

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Problems solved by technology

Since the hydrophobic alkyl group is located on the side chain of PEG, the water reducer of the present invention has the following four main advantages: 1. Its content does not affect the adsorption and dispersion of -COO in the copolymer - 2. The content of hydrophobic alkyl groups can be adjusted at will according to the actual needs of the viscosity-reducing effect, so as to effectively solve the problems of high viscosity and slow flow rate in high-grade concrete. Purpose; 3. Since the PEG side chain contains a large number of hydrophobic viscosity-reducing alkyl groups, the water reducer molecules cannot form a complete water film on the surface of cement particles, but form a collapsed water film with defects. The water layer film endows the water reducing agent with the following characteristics: (1) It can release more free water and reduce the viscosity of cement paste; (2) The molecular weight of the water reducing agent is not limited by the viscosity reduction requirements; (3) PEG The length of the side face is not limited by the requirement for viscosity reduction; 4. The large amount of hydrophobic alkyl groups introduced into the PEG side chain greatly reduces the surface tension of the product and reduces the shrinkage force of water evaporation, thereby reducing the shrinkage and cracking of concrete. good downscaling

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