Low-sensitivity water-reducing slump-retaining polycarboxylic acid water reducer and preparation method thereof

Abstract

The invention discloses a low-sensitivity water-reducing slump-retaining polycarboxylic acid water reducer and a preparation method thereof, and relates to the technical field of concrete admixtures. The invention provides a structural formula and a preparation method of a low-sensitivity type water-reducing and slump-retaining polycarboxylic acid water reducer, and also provides application of the low-sensitivity type water-reducing and slump-retaining polycarboxylic acid water reducer in preparation of concrete. The water reducer provided by the invention has high water reducing and slump retaining properties, also has good mud-resistant and weather-resistant characteristics, and meets the workability of concrete under the conditions of raw material fluctuation, high temperature, long-distance transportation and the like.

Description

technical field [0001] The invention relates to the technical field of concrete admixtures, in particular to a low-sensitivity water-reducing and slump-retaining polycarboxylate water-reducer and a preparation method thereof. Background technique [0002] Polycarboxylate superplasticizer is the third generation of high-performance superplasticizer. Compared with the previous two generations of superplasticizers, it has the advantages of low dosage, strong molecular designability, and environmental protection. It is widely used in roads, railways, bridges, etc. It is currently the most widely used concrete admixture in the fields of , dams and high-rise buildings. [0003] However, the natural resource consumption of concrete raw materials is huge, and high-quality sand and stone resources are almost exhausted. It has become a development trend to apply low-quality aggregates such as construction solid waste, machine-made sand, and natural sand with high mud content to concre...

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Problems solved by technology

[0004] But at present, with the introduction of phosphoric acid groups, the dispersion performance of polycarboxylate superplasticizer is greatly improved, but the improvement of slump retention effect and adaptability is still not ideal

The reason may be that in the prior art, by introducing phosphoric acid group functional monomers into polycarboxylic acid molecules, the excellent complexation adsorption capacity and stronger electronegativity of the phosphoric acid group are used to effectively improve the dispersion ability of the water reducer, and the performance However, the clay has an intercalation structure, while the superplasticizer molecules have a comb-like structure, and the long side chains will enter the clay intercalation and be chemically adsorbed by the clay surface, and the phosphoric acid group will also be absorbed by the clay surface. The effect of such intercalation adsorption cannot be eliminated. Once the raw materials fluctuate greatly, the concrete will easily show a large slump loss and cannot meet the construction requirements.

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