A kind of viscosity-reducing high-efficiency water-reducing polycarboxylate water-reducer and its preparation method

A water-reducing polycarboxylic acid and water-reducing agent technology, which is applied in the field of concrete water-reducing agent and its preparation, can solve practical problems that cannot be completely solved, low concrete fluidity, increased construction costs, etc., and achieve tight distribution and improved Water reduction rate, viscosity reduction effect, and surface tension reduction effect

Active Publication Date: 2021-07-30
HUNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current problems are: the extremely low water-cement ratio of UHPC leads to high viscosity of the slurry, and the addition of mineral admixtures, especially silica fume, makes the workability of UHPC worse, that is, the fluidity of concrete is low
For the first technology, since the amount of cementitious material in UHPC is more than 4 times that of ordinary concrete, resulting in the amount of admixtures as high as 15-20 times that of ordinary concrete, it will increase the high construction cost
The second technique has been studied a lot, but it cannot completely solve practical problems

Method used

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  • A kind of viscosity-reducing high-efficiency water-reducing polycarboxylate water-reducer and its preparation method
  • A kind of viscosity-reducing high-efficiency water-reducing polycarboxylate water-reducer and its preparation method
  • A kind of viscosity-reducing high-efficiency water-reducing polycarboxylate water-reducer and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] First weigh 137g of isopentenol polyoxyethylene ether with a molecular weight of 2400, 8.2g of dihydroxyfumaric acid and 100g of water and put them into a four-neck flask for stirring. After all the monomers are dissolved, pour 1.8g of hydrogen peroxide and stir 1-2min, then start to gradually add 0.3g ascorbic acid and 30g water A liquid, 0.76g mercaptothiol and 50g water B liquid at the same time, after AB liquid is added dropwise for 1 hour, weigh 8.2g of dihydroxy fumaric acid and add it to the flask At the same time, continue to add AB solution dropwise, add AB solution dropwise for 2 hours, keep warm for 2 hours after both are completed at the same time, and finally neutralize with sodium hydroxide to pH 6.7. That is, the viscosity-reducing high-efficiency water-reducing polycarboxylate superplasticizer PC-1 is obtained.

Embodiment 2

[0030] First weigh 140g of isopentenol polyoxyethylene ether with a molecular weight of 2400, 12g of dihydroxyfumaric acid and 100g of water and stir in a four-necked flask. After all the monomers are dissolved, pour 1.8g of hydrogen peroxide and stir for 1 -2min, then began to gradually dropwise add 0.3g ascorbic acid and 30g water A solution, 0.36g mercaptothiol, 0.36g mercaptopropionic acid and 50g water B solution, after AB solution was added dropwise for 1h, weigh 12g of dihydroxy Fumaric acid was added to the flask, and at the same time, the AB solution was continued to be added dropwise, and the AB solution was added dropwise for a total of 2 hours. After the two were completed at the same time, the reaction was kept for 2 hours, and finally neutralized with sodium hydroxide to a pH of 6.7. That is, the viscosity-reducing high-efficiency water-reducing polycarboxylate superplasticizer PC-2 is obtained.

Embodiment 3

[0032]First weigh 150g of isopentenol polyoxyethylene ether with a molecular weight of 2400, 6g of dihydroxyfumaric acid and 100g of water and stir in a four-neck flask. After the monomers are completely dissolved, pour 2.0g of hydrogen peroxide and stir for 1 -2min, then start to gradually add dropwise the A solution of 0.53g ascorbic acid and 30g water, the B solution of 0.8g mercaptothiol and 50g water at the same time, after the AB solution is added dropwise for 1h, add 6g of dihydroxy fumaric acid into the flask, At the same time, continue to add AB solution dropwise, add AB solution dropwise for 2 hours, keep warm for 2 hours after both are completed at the same time, and finally neutralize with sodium hydroxide until the pH is 6.7. That is, the viscosity-reducing high-efficiency water-reducing polycarboxylate superplasticizer PC-3 is obtained.

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Abstract

A viscosity-reducing high-efficiency water-reducing polycarboxylate water-reducer and its preparation method, the water-reducer is composed of macromonomers such as isopentenol polyoxyethylene ether monomers, unsaturated hydroxy acid monomers or derivatives thereof, Or the unsaturated acid with trans structure is prepared by free radical polymerization under the action of reducing agent, oxidizing agent and chain transfer agent by intermittent dropping. The anchor groups and side chains in the water reducer of the present invention are block-distributed molecular structures, which can give full play to the electrostatic repulsion and steric hindrance effects; in addition, the hydroxyl groups introduced by unsaturated hydroxyacid monomers or their derivative monomers Polar groups such as carboxyl and carboxyl groups increase the proportion of hydrophilic groups and reduce the surface tension of the cement pore solution; in addition, the trans structure represented by fumaric acid and dihydroxy fumaric acid derivatives, due to its special The structure, that is, the rigidity of the monomer itself and its two carboxyl groups are distributed on the opposite side of the side chain, which makes it easy to show a stretched structure in space, reduces the possibility of molecular chain entanglement, and significantly increases the polycarboxylate superplasticizer. Adsorption on the surface of cement, thereby improving the viscosity-reducing effect of polycarboxylate superplasticizer.

Description

technical field [0001] The invention relates to a water-reducing agent for concrete and a preparation method thereof, in particular to a viscosity-reducing high-efficiency water-reducing polycarboxylate water-reducer for ultra-high performance concrete and a preparation method thereof. Background technique [0002] Because polycarboxylate superplasticizer (PC) has the advantages of low dosage, high water reduction and high slump retention, it has become one of the main components of high-performance concrete. PC usually consists of a main chain containing anionic groups and polyethylene oxide (PEO) side chains, exhibiting a unique comb-like structure. The electrostatic repulsion generated by the anion adsorption of the PC main chain on the surface of cement particles and the steric hindrance generated by the side chains extending in the solution achieve the effect of dispersing cement. This mechanism has been recognized by most people. [0003] Ultra-high performance concre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F283/06C08F222/02C04B24/26C04B103/30
CPCC04B24/2694C04B2103/302C08F283/065C08F222/02
Inventor 史才军沙胜男王敏白静静
Owner HUNAN UNIV
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