Mud resistant slow release type slump retaining agent containing cyclodextrin side group and preparation method thereof

Abstract

The invention discloses a mud resistant slow release type slump retaining agent containing a cyclodextrin side group and a preparation method thereof. The method synthesizes a mud resisting ester monomer by introducing a beta-cyclodextrin structural unit with appropriate steric hindrance and better water solubility to be subjected to an esterification reaction with fumaric acid. In alkaline environment of cement hydration, with the slow release of the mud resisting ester monomer, the beta-cyclodextrin introduced into the molecular structure of a water reducer can effectively weaken interpenetration between water reducer molecules and a clay layer because particles of the beta-cyclodextrin distribute in a range of 0.53-1.78 nm which is close to 1.44-1.86 nm that is the interlayer spacing ofbentonite, and so the polycarboxylic acid water reducer is good in mud resistance and slump retaining effect. Meanwhile, a phosphoric acid monomer is introduced into the molecular structure of the water reducer to further improve the mud resisting effect. The mud resistant slump retaining type polycarboxylic acid water reducer containing a cyclodextrin side group prepared by the method of the invention has the advantages of low dosage, long slump retaining time, strong mud resistance and the like, and is easy in synthesis process, safe, environmentally friendly and low in production cost.

Description

technical field [0001] The invention relates to the technical field of concrete admixture synthesis, and specifically provides a mud-resistant slow-release slump-retaining agent containing cyclodextrin side groups and a preparation method thereof. Background technique [0002] Polycarboxylate superplasticizer is a high-performance concrete admixture. It has been widely used in the medium and low grade ready-mixed concrete industry due to its advantages of low mixing, high water reduction, environmental protection and strong functionality. However, polycarboxylate superplasticizers are more sensitive to aggregate clay content. With the gradual reduction of high-quality sand and gravel aggregate resources and the continuous increase of aggregate mud content, the adaptability of polycarboxylate superplasticizers to cement becomes worse, the fluidity of concrete is poor, and the slump loss becomes faster, etc. series of questions. Simply increasing the amount of water reducing...

AI Technical Summary

Problems solved by technology

Although the problem of concrete fluidity can be improved, the loss of concrete slump is relatively fast, and further research is needed

[0004] Patent CN 103819637 A discloses a polycarboxylic acid-based water reducer containing β-cyclodextrin and lignin. The invention improves the water retention and cohesion of concrete by introducing β-cyclodextrin, and to a certain extent It improves the strength of concrete, but its slump protection and anti-mud effects are poor

[0005] Patent CN 102153711 A discloses a method for preparing a retarded polycarboxylate superplasticizer. The polycarboxylate superplasticizer prepared by the invention has stable performance, strong cement adaptability, and good compatibility. It can reach 30-40%, and the slump retention time is 3-5 hours, but its anti-mud effect is poor

[0006] Patent CN 105837738 A discloses a polycarboxylate cationic anti-mud agent and its preparation method and application. The polycarboxylate water-reducer product prepared by the invention has a strong dispersion effect under the condition of the same aggregate mud content. It can improve the strength of concrete, but its anti-mud effect is limited, and the effect of slump protection is insufficient

[0007] Patent CN 102229479 A discloses a water-retaining polycarboxylate water reducer containing β-cyclodextrin and its preparation and use method. The water reducer has good water reduction and water retention performance, but its slump retention effect Poor, not to mention its anti-mud effect

[0008] In recent years, people have improved the mud resistance of the water reducer by introducing β-cyclodextrin, but this will affect the slump retention effect of the water reducer, resulting in a faster loss of the slump of the water reducer or the dispersibility of the water reducer. reduce

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