Modified polycarboxylate superplasticizer and preparation method thereof

Abstract

The invention provides a preparation method of a modified polycarboxylate superplasticizer and the modified polycarboxylate superplasticizer prepared by the method. The method comprises the following steps: firstly, using all raw materials to prepare an aqueous solution, namely dissolving part of acrylic acid hydroxyl ester and a polyether macromonomer in water to prepare a solution A, then dissolving the other part of acrylic acid hydroxyl ester and unsaturated acid in water to prepare a solution B, dissolving a reduction initiator and a chain transfer agent in water to prepare a solution C, and dissolving a cationic modifier in water to prepare a solution D; and secondly, gradually reacting the raw materials according to a fixed charging sequence: adding an oxidation initiator into the solution A to obtain a solution E, and conducting stirring for 5-10 min, then dropwise adding the solution B, the solution C and the solution D into the solution E at the same time, conducting stirring while dropwise adding is conducted, and after dropwise adding of the solution C is completed, continuing the reaction for 1-2 h, so as to obtain a modified polycarboxylate superplasticizer solution. The modified polycarboxylate superplasticizer prepared by the method can keep the slump of concrete at 30 DEG C for at least 3 hours without loss, and the loss amplitude is kept within 3% after 4 hours.

Description

technical field [0001] The invention belongs to the field of concrete admixtures, and relates to a preparation method of a modified polycarboxylate water reducer and the modified polycarboxylate water reducer prepared according to the method. Background technique [0002] Polycarboxylate superplasticizer, as the third generation of high-performance concrete superplasticizer, has the advantages of low dosage and high water-reducing rate, and has become an essential material and core technology for manufacturing high-performance modern concrete. However, with the improvement of concrete performance requirements in modern engineering, the simple high water reducing rate can no longer meet the engineering requirements for polycarboxylate water reducing agent performance. At present, in the application process of commercial concrete, one of the most common and main problems is the loss of concrete slump. Ready-mixed concrete is commonly used in modern engineering. The production...

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Problems solved by technology

[0004] In order to solve the problem that the slump loss is too large due to the long time of concrete transportation, especially the problem that the slump is more likely to be lost under high temperature in summer, the invention provides a preparation method of a modified polycarboxylate water reducer. The modified polycarboxylate water-reducer prepared by this method is added to concrete, and the slump of concrete can be kept at 30°C for 3 hours without loss, and the range of slump loss for 4 hours does not exceed 3%.

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