High-performance polycarboxylic acid water reducing agent and preparation method thereof

Abstract

The invention relates to a high-performance polycarboxylic acid water reducing agent and a preparation method thereof, and belongs to the technical field of concrete admixtures in the construction industry. The high-performance polycarboxylic acid water reducing agent is a high molecular surfactant with a comb-type structure, wherein the high molecular surfactant is obtained by compounding of macromolecular compounds, comprising carboxyl and functional groups such as polyoxyethylene long chains, through free radical copolymerization with the presence of water as a solvent. Molecular main chains of the high-performance polycarboxylic acid water reducing agent are tightly adsorbed on the surfaces of cement particles, so that hydration reactions can be effectively inhibited to improve the plasticity retention; branch chains surround the cement particles to achieve the double effect of steric hindrance and electrostatic repulsion, which is completely different from the mechanism in which conventional water reducing agents disperse the cement particles through the electrostatic repulsion, so that high dispersing ability and good water reducing effect are achieved, and the comprehensiveperformance of concrete products is substantially boosted.

Description

technical field [0001] The invention relates to the technical field of concrete admixtures in the construction industry, in particular to a polycarboxylate high-performance water reducer used in cement slurry, mortar and concrete and a preparation method thereof. Background technique [0002] With the country's increasing efforts in infrastructure construction, the demand and performance requirements for concrete are increasing year by year. Similarly, the demand for high-performance water-reducing agents with the advantages of high water-reducing rate, low dosage, low alkali content, and environmental friendliness is also increasing. As an important raw material in concrete—concrete high-efficiency water reducer has become an indispensable new material for national capital construction. [0003] Compared with high-efficiency water reducers such as naphthalene, melamine, and sulfamate, polycarboxylate water reducers have more excellent properties, such as low dosage, high w...

AI Technical Summary

Problems solved by technology

However, in the actual application process, there are still many problems in the use of polycarboxylate water reducers, such as the crushed concrete mixed with modified mineral powder and machine-made sand.

The modified slag powder has a large water absorption capacity, which has a strong adsorption effect on the molecular structure of the water reducer, and inhibits the dispersion performance of the water reducer; the amount of machine-made sand used in debris concrete is more than 70%, and the mud content of machine-made sand is high. , the adsorption capacity of the water reducing agent is large, resulting in poor adaptability between the water reducing agent and concrete, and rapid loss of slump

There is also the problem of poor concrete slump in medium and small slump concrete, especially in summer high temperature environment, sometimes the fluidity of concrete in 2 hours is very small, which seriously affects the application of concrete

Polycarboxylate water reducers have the problem of excessive slump loss, which urgently requires the development of polycarboxylate water reducers with super slump retention capabilities. This type of admixture can be used alone or It can be used in combination with the existing polycarboxylate admixture to solve the technical problem of poor slump retention of the existing polycarboxylate admixture

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