Preparation method of mud-resistant polycarboxylate-type water reducer

Abstract

The invention relates to a preparation method of a mud-resistant polycarboxylate-type water reducer. The preparation method comprises the following specific steps: stirring an unsaturated small monomer containing an epoxy group, a secondary amine small organic molecule and a small organic molecule containing halogen at certain temperature under the action of a catalyst to obtain a product of quaternary ammonium salt unsaturated small monomer; carrying out water phase free radical polymerization reaction on the quaternary ammonium salt unsaturated small monomer, an unsaturated ester small monomer, an unsaturated sulfoacid small monomer, an unsaturated acid small monomer and an unsaturated polyether large monomer under the combined action of an initiator and a chain transfer agent to obtain a copolymerized product, regulating the pH value after reaction and adding water to obtain the polycarboxylate-type water reducer. The mud-resistant polycarboxylate-type water reducer prepared by the method has the advantages of being simple in reaction, easy to control and low in cost. Besides, adverse effect caused by mud-containing aggregate in the concrete can be avoided, and the problems of insufficient concrete slushing, large slump loss and low strength are solved without increasing the mixing amount of the water reducer.

Description

technical field [0001] The invention relates to the technical field of a polycarboxylate water-reducing agent for cement concrete, in particular to a preparation method of a mud-resistant polycarboxylate water-reducing agent using amino-epoxy ring-opening reaction and free radical polymerization. Background technique [0002] In recent years, with the in-depth research and application of polycarboxylate superplasticizers, it has been found that polycarboxylate superplasticizers have poor adaptability to concrete with high mud content and gravel, and the slump loss of fresh concrete is very fast, which is difficult to guarantee. Transportation, pumping and construction have become a thorny problem in the application field of polycarboxylate superplasticizers at home and abroad. In terms of mechanical properties of concrete, the high content of sand and mud will affect the strength of concrete; in terms of concrete workability, it affects the slump of concrete and accelerates ...

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Problems solved by technology

But at the same time, it should also be noted that the quality control of raw materials for such large-scale projects is strict. While polycarboxylate superplasticizers exert their powerful effects, their shortcomings and shortcomings are often covered up.

In the field of industrial and civil construction projects, it is often difficult to ensure the quality of concrete raw materials, especially the fluctuations in the mud content of sand and gravel aggregates are relatively large, and the disadvantages of poor adaptability between polycarboxylate superplasticizer and inferior mud-containing sand also stand out

Furthermore, the clay content in sand and gravel in different regions is not the same. For example, the clay content in sand and gravel in Northeast and Northwest my country is very high, and sometimes even when the mud content is only 2 to 3%, the workability of the concrete mixture will be affected. has gotten worse

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