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Ultra-long sustained-release polycarboxylate slump retaining agent and preparation method thereof

A slow-release polycarboxylic acid and slump-retaining agent technology, applied in the field of concrete, can solve the problems of poor encapsulation, scarcity, bleeding, etc., and achieve the effects of promoting the growth of early strength, simple preparation method and easy control of conditions.

Active Publication Date: 2022-02-08
CCCC SHEC WUHAN PORT NEW MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, high-quality sand and stone aggregates are increasingly scarce, and low-quality sand and gravel materials such as high-mud sand, washed sand, mountain sand or artificial tailings sand, and their mixed sand are gradually used in various large-scale projects, making It is also more difficult to maintain the fluidity of fresh concrete
Although the emergence of some polycarboxylic acid slump-retaining agents at home and abroad has improved the problem of poor slump retention of fresh concrete to a certain extent, due to some special requirements for design and construction or limitations in construction technology and environmental conditions, such as: Ultra-long-distance transportation, ultra-long-time pouring, ultra-long-term high temperature, etc., often cause the slump retention time of fresh concrete to be short, and the slump protection effect is poor. In actual construction, problems such as poor wrapping, bleeding, and segregation are prone to occur.

Method used

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  • Ultra-long sustained-release polycarboxylate slump retaining agent and preparation method thereof
  • Ultra-long sustained-release polycarboxylate slump retaining agent and preparation method thereof
  • Ultra-long sustained-release polycarboxylate slump retaining agent and preparation method thereof

Examples

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preparation example Construction

[0031] The preparation method of the ultra-long slow-release polycarboxylate slump-retaining agent of the present invention comprises the following steps:

[0032] 1) Add 4-hydroxybutyl vinyl polyoxyethylene ether and deionized water into the reaction kettle, stir and dissolve to obtain A solution;

[0033] 2) Heat solution A to the initial reaction temperature, add hydrogen peroxide to solution A, and simultaneously dropwise add deionized water mixed solution of acrylic acid, hydroxypropyl acrylate and maleyloxyethylpyrrolidone, mercaptopropionic acid and The deionized water mixed solution of ascorbic acid, after the dropwise addition, continues the insulation reaction, and finally cools to room temperature to obtain the B solution;

[0034] 3) Add a 30% mass fraction of sodium hydroxide solution to the B solution, adjust the pH value to 6-7, and obtain a 40% mass fraction of ultra-long slow-release polycarboxylic acid slump-retaining agent; 4-hydroxybutyl vinyl The molar ra...

Embodiment 1

[0036] (1) Synthesis of maleoyloxyethylpyrrolidone: at room temperature, pass nitrogen gas into the reaction kettle for 10 minutes, then add hydroxyethylpyrrolidone and maleic anhydride in sequence, continue to pass nitrogen gas, stir, heat up to 50°C and start to keep warm, control The reaction temperature is between 55°C and 70°C, and the reaction time is 1.0h. After the reaction is completed, the temperature is lowered to below 45°C with cooling water, and the nitrogen gas is stopped to obtain a liquid maleoyloxyethylpyrrolidone monomer; hydroxyethylpyrrolidone , The molar ratio of maleic anhydride is 1.0:1.0.

[0037] (2) Polymerization reaction: Add 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 2400 and deionized water into the reaction kettle, stir and dissolve to obtain A solution; heat A solution to 25°C, and pour into A solution Add hydrogen peroxide, and drop the deionized water mixed solution of acrylic acid and maleyloxyethylpyrrolidone and ...

Embodiment 2

[0039] (1) Synthesis of maleoyloxyethylpyrrolidone: same as Example 1.

[0040](2) Polymerization reaction: Add 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 2400 and deionized water into the reaction kettle, stir and dissolve to obtain A solution; heat A solution to 30°C, and pour into A solution Add hydrogen peroxide, and drop the deionized water mixed solution of acrylic acid and maleyloxyethylpyrrolidone and the deionized water mixed solution of mercaptopropionic acid and ascorbic acid respectively at the same time. The dropping time is 2.0h. After the dropping is completed, the Continue the heat preservation reaction at 35°C for 1.0h, and finally cool to room temperature to obtain solution B; add 30% sodium hydroxide solution to solution B, adjust the pH value to 6-7, and obtain a super-long buffer with a mass fraction of 40%. Release-type polycarboxylic acid slump-retaining agent, denoted as B2, with a measured molecular weight of 43728; 4-hydroxy...

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Abstract

The invention discloses an ultra-long slow-release polycarboxylic acid slump-retaining agent and a preparation method thereof. The molecular formula is: wherein, a, b, c, d and n are degrees of polymerization and are all positive integers, and a=12-18 , b=18-45, c=12-27, d=30-54, n=50-90. The polycarboxylate slump-retaining agent prepared by the invention can be continuously hydrolyzed for a long time in the alkaline environment of concrete, continuously release polycarboxylate superplasticizer molecules, supplement the consumption of cement hydration on the superplasticizer, and achieve a super long time The continuous maintenance of slump also has a certain effect of promoting early strength of concrete; the process of preparation is simple, the conditions are easy to control, and the operability is high.

Description

technical field [0001] The invention relates to the technical field of concrete. More specifically, the present invention relates to an ultra-long sustained-release polycarboxylate slump retaining agent and a preparation method thereof. Background technique [0002] In recent years, the cement used in concrete has become finer, the water-binder ratio is lower, and the colloidal composition is more complex. The quality of various admixtures such as fly ash, mineral powder, and silica fume is also very different. At the same time, high-quality sand and stone aggregates are increasingly scarce, and low-quality sand and gravel materials such as high-mud sand, washed sand, mountain sand or artificial tailings sand, and their mixed sand are gradually used in various large-scale projects, making It is also more difficult to maintain the fluidity of fresh concrete. Although the emergence of some polycarboxylic acid slump-retaining agents at home and abroad has improved the problem...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F283/06C08F220/06C08F220/20C08F222/22C04B24/26
CPCC08F283/065C04B24/2694C04B2103/308C08F222/22
Inventor 高玉军李顺凯沈尔卜吴克雄王文荣
Owner CCCC SHEC WUHAN PORT NEW MATERIALS