Preparation method of high water-reducing and slump-preserving polycarboxylate water reducer by four-drop method

Abstract

The invention discloses a four-dropwise addition method for preparing a high-water reduction and slump loss-resistant polycarboxylic water reducer. The four-dropwise addition method comprises the following preparation steps: 1), placing a polyether macromonomer and water into the bottom of a kettle, stirring until a solution has no significant block material or sheet material, and adding an inorganic peroxygen initiator and a trace amount of ferrous sulfate when the initial temperature is lower than or equal to 22 DEG C; 2), 5min later, simultaneously starting to dropwise add a reducing chaintransfer compound solution and an oxidizer solution for a hour; 3), 5min later, starting to dropwise add a small monomer solution for a-0.5 hour; 4), 20min later, starting to dropwise add a liquid caustic soda solution for a+0.5 hour; 5) after dropwise addition of the liquid caustic soda solution, preserving heat for 0.5-2.0 hours, stopping stirring to obtain a finished mother solution. The polycarboxylic water reducer has the dual characteristics of high water reduction and high slump loss resistance, is strong in adaptability, and can significantly improve the slump loss resistance, the cohesiveness and the flowing retention ability of freshly mixed concrete.

Description

Technical field [0001] The invention relates to the technical field of a polycarboxylic acid water-reducing agent, in particular to a four-drop addition method for preparing a high water-reducing and slump-keeping polycarboxylic acid water-reducing agent. Background technique [0002] Concrete water reducer is the fifth component of concrete. It is mainly polycarboxylic acid water reducer. It has the advantages of high water reduction rate, good slump retention, etc., and the synthesis process is simple, the production process is free of pollutants, and it is green Environmentally friendly and cost-effective. At present, there are many factors that affect the working state of concrete, such as sand, cement, and mineral admixtures. Correspondingly, concrete admixtures fluctuate greatly. If the molecular weight of the water reducer is too small, it is easy to be consumed. According to different materials, the distribution coefficient of the molecular weight of the water-reducing ...

AI Technical Summary

Problems solved by technology

The double-dropping mode generally puts the oxidizing agent directly at the bottom of the kettle, and the reducing agent and the small monomer solution are added dropwise in batches. This traditional dropping method does not consider the half-life of the oxidizing agent, and the reactivity is poor. This method will have a certain probability of normal temperature When the process fails to trigger the temperature rise normally, during the double dropping process, the pH value of the reaction solution tends to be less than 3 in the later stage of the dropping, and the triggering efficiency decreases