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Preparation method for polycarboxylic acid type concrete slump-retaining agent

A technology of slump retaining agent and concrete, which is applied in the field of preparation of polycarboxylate concrete slump retainer, can solve the problems of poor workability of concrete mixture, increase of retarding components, large slump loss, etc., and achieve excellent slump Slump retention ability, good slump retention, simple synthesis process

Active Publication Date: 2013-07-03
SHANXI HUANGTENG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the late start of domestic polycarboxylate superplasticizers, the current supply of polycarboxylate superplasticizers in the market generally has poor concrete slump retention.
Solving the problem of slump loss in the process of concrete trial mixing has always been a headache for all technicians. Due to the wide variety of domestic cements and various types, and the different components of sand, stone and admixtures in various places, the admixture and admixture are different. The adaptability of cement is poor, and due to the influence of various factors such as cement fineness, alkali content, aluminate content and grinding aids, the slump loss is too large, especially for the small slump mix ratio required by beam making (The machine is small, and the loss over time is even smaller); in addition, the temperature in summer is high, and the hydration of cement is accelerated, resulting in increased slump loss
The increase of the retarding component of the former will often cause the concrete mixture to prolong the setting time, affect the early strength, and cause engineering quality accidents if the control is not good; while increasing the water reducing rate, it is easy to make the concrete mixture poor workability and leakage. Water, segregation, and bottom removal affect the working performance of the mixture and increase the difficulty of construction
According to a lot of practice, the cement in the north of my country is less adaptable to admixtures than the cement in the south

Method used

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  • Preparation method for polycarboxylic acid type concrete slump-retaining agent
  • Preparation method for polycarboxylic acid type concrete slump-retaining agent

Examples

Experimental program
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Effect test

example 1

[0037] First add 280g of deionized water to the reactor, start stirring and add 400g of modified polyether, heat up to 60±2°C, add liquid C, stir for 5 minutes, start to add liquid A and liquid B dropwise, of which liquid A: 3.0 hours After the dropwise addition is completed, the dropwise addition of liquid B is completed in 4.0 hours, and the dropwise addition temperature is 60±2°C; after that, keep the temperature for 2 hours, cool down to 50°C, add 80g of 30% liquid caustic soda for neutralization, and control the pH: 6.0~7.0. Adjust the concentration of the system to 40% (preparation of liquid A: dissolve 0.28 g of thioglycolic acid and 1 g of ascorbic acid into 80 g of deionized water for later use; preparation of liquid B: dissolve 45 g of acrylic acid in 15 g of deionized water for later use; preparation of liquid C, Add 6 g of 32.5% hydrogen peroxide into 15 g of deionized water for subsequent use).

example 2

[0039] First add 280g of deionized water into the reactor, start stirring and add 400g of modified polyether, raise the temperature to 70±2°C, add liquid C, and stir for 5 minutes. Start to add liquid A and liquid B dropwise, among which liquid A is added dropwise in 4 hours, and liquid B is added in 3 hours. The dropping temperature is kept at 75±2°C. After that, keep the reaction for 1 hour, lower the temperature to 50°C, add 45g of 30% liquid caustic soda for neutralization, and control the pH: 6.0-7.0. Adjust the concentration of the system to 40% (preparation of liquid A, dissolve 2 g of mercaptopropionic acid, 1 g of thioglycolic acid and 2 g of ascorbic acid into 80 g of deionized water, and set aside; preparation of liquid B: dissolve 45 g of methacrylic acid in 15 g of deionized water ; Standby; C liquid preparation, 32.5% hydrogen peroxide 3g ammonium persulfate 2g was added to 15g deionized water; standby).

example 3

[0041] First add 280g of deionized water into the reactor, start stirring and add 400g of modified polyether, raise the temperature to 65±2°C, add liquid C, stir for 5 minutes, and add liquid A and liquid B dropwise at the same time. Add solution A in 5 hours, add solution B in 4 hours, then keep warm for 2 hours, the reaction temperature is 65±2°C, cool down to 50°C, add 75g of 30% liquid caustic soda for neutralization, and control pH: 6.0~7.0. Adjust the concentration of the system to 40% (preparation of liquid A: dissolve 3 g of sodium bisulfite and 1 g of mercaptopropionic acid in 80 g of deionized water for later use; preparation of liquid B: dissolve 20 g of methacrylic acid and 20 g of maleic anhydride in 40 g of deionized water Standby; 32.5% hydrogen peroxide 6g is dissolved in 15g deionized water for standby).

[0042] The comparison results of polycarboxylic acid slump-retaining agent of the present invention with ester water reducer and ether water reducer are sho...

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Abstract

The invention provides a preparation method for a polycarboxylic acid type concrete slump-retaining agent, wherein the slump-retaining agent is a polycarboxylic acid copolymer obtained by dissolving modified polyether and unsaturated polycarboxylic acid in aqueous solution, adopting a redox system, and synthesising under the action of a chain transfer agent; the molar ratio of the modified polyether to the unsaturated polycarboxylic acid is 1: (1.0 to 7.0); the dosage of an oxidant is 0.2-5.0% in ratio by weight of the total of the modified polyether and the unsaturated polycarboxylic acid; the dosage of a reductant is 0.02-4.0% in ratio by weight of the total of the modified polyether and the unsaturated polycarboxylic acid; and the dosage of the chain transfer agent is 0.03-6.0% in ratio by weight of the total of the modified polyether and the unsaturated polycarboxylic acid. The method provided by the invention has no need of independently preparing a polymerized macromonomer, as well as is low in reaction temperature, simple in process, and convenient to operate. The slump-retaining agent prepared by the method provided by the invention is excellent in slump-retaining capacity.

Description

technical field [0001] The invention relates to a preparation method of a concrete slump retaining agent, in particular to a preparation method of a polycarboxylate concrete slump retaining agent with excellent slump retaining function. Background technique [0002] Looking at the development history of domestic concrete admixtures, it can be roughly divided into three stages, ordinary water reducers based on lignin sulfonate and sugar calcium; naphthalene sulfonate formaldehyde condensate, melamine formaldehyde condensate, High-efficiency water reducer based on sulfamate formaldehyde condensate; polycarboxylate water reducer belongs to the third generation chemically synthesized high-performance admixture. Compared with high-efficiency water reducers, polycarboxylate water reducers are favored by users for their high water reducing rate, low dosage, no bleeding, no segregation, and good concrete slump retention. However, due to the late start of domestic polycarboxylate su...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F283/06C08F4/40C08G65/28C04B24/26
Inventor 孙克俭孙肖武王世兴惠蔷
Owner SHANXI HUANGTENG CHEM
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