High-slump-retaining polycarboxylic acid composite water reducer and preparation method thereof

Abstract

The invention belongs to the field of building material additives and particularly relates to a high-slump-retaining polycarboxylic acid composite water reducer and a preparation method thereof. The polycarboxylic acid composite water reducer is prepared from, by weight, 100 parts of unsaturated polyoxyethylene ether macromonomer, 0.5-2 parts of oxidizing agent, 0.1-0.4 part of reducing agent, 0.4-0.8 part of chain transfer agent and 10-15 parts of comonomer. The preparation process of the high-slump-retaining polycarboxylic acid composite water reducer is easy and convenient to operate and environmentally friendly, and saves energy. The high-slump-retaining polycarboxylic acid composite water reducer is prepared from, by weight, 45-55% of polycarboxylic acid water reducer, 10-15% of modified attapulgite, 2-4% of retarder, 0.03-0.08% of defoamer, 0.01-0.05% of air entraining agent, 5-8% of absolute ethyl alcohol, 4-7% of modified hydrotalcite and the balance water. The high-slump-retaining polycarboxylic acid composite water reducer is good in adaptability and has excellent dispersion, slump retaining and slow release performance.

Description

technical field [0001] The invention belongs to the field of building material additives, in particular to a high-slump polycarboxylic acid composite water reducer and a preparation method thereof. Background technique [0002] As a building functional material, concrete is made by mixing cement, granular aggregates, water, mineral admixtures and chemical admixtures in a certain proportion. Due to its good durability, high compressive strength and low price It is cheap and rich in raw materials, and has become one of the most widely used structural materials in the world, and has become an important pillar of the national economy. [0003] Water reducing agent is one of the necessary components of chemical admixtures, its main function is to reduce the mixing water consumption under the condition of maintaining the slump of concrete. The emergence of water-reducing agents has brought about fundamental changes in many concrete technologies and concepts, especially polycarbox...

AI Technical Summary

Problems solved by technology

[0004] However, in recent years, due to more and more infrastructure projects, the consumption of concrete raw materials is also increasing, resulting in less and less high-quality resources, which further exacerbates the adaptability of polycarboxylate superplasticizers to these concrete raw materials, which needs to be solved urgently

For example: (1) At present, there is a common problem of high mud content in commercially available sand and gravel, which not only reduces the strength and life of concrete, but also seriously affects the dispersibility of polycarboxylate superplasticizer, thereby increasing concrete drying shrinkage , these clays are generally montmorillonite, kaolin, etc.; (2) There are a lot of carbon particles in the existing commercially available cementitious materials, such as fly ash, which are easy to adsorb polycarboxylate superplasticizer, affecting its dispersion performance

(3) Most of the existing polycarboxylic acids use graft copolymerization branches at the molecular structure level to play a slow-release effect, the cost is high, and the effect cannot fully meet the requirements

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