Carboxylic acids graft copolymer concrete strengthening agent

Abstract

A kind of carboxylic acid graft copolymer concrete slump retaining agent is prepared by the following steps: 1) monoalkyl polyether or dihydroxy polyether and monoalkyl polyether and bishydroxy polyether described in general formula (I) The mixture of hydroxypolyether and dibasic unsaturated carboxylic acid or acid anhydride undergoes grafting reaction under acid catalyst conditions to generate macromonomer a with C=C; 2) the grafted macromonomer mixture a prepared in step 1) is mixed with The monomer b is mixed and copolymerized at a weight ratio of 70-97% and 3-30% respectively. The invention can obviously improve the slump loss of the traditional naphthalene-based water reducer, improve its dispersion performance, and not prolong the setting time of concrete, and has good plastic retention for medium and low slump concrete or high fluidity concrete Effect; It has good adaptability to other high-efficiency water-reducing agents, whether it is used in combination with traditional naphthalene-based water-reducers and melamine-based water-reducers or with new polycarboxylate-based water-reducers. The ability to maintain slump; the production process does not produce three wastes.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures in building materials, and in particular relates to a carboxylic acid graft copolymer that can be used as a high-efficiency slump-retaining agent for concrete. Background technique [0002] With the development of transportation, hydropower, municipal and other construction projects, the gradual rise of high-span bridges, hundreds of stories of high-rise buildings, and oil drilling platforms, offshore airports, offshore cities, and submarine tunnels, the construction performance and strength of concrete The requirements for indicators and durability are getting higher and higher, and almost all of them require the use of pumped concrete, and high-efficiency water reducers are the fifth component that is indispensable for the preparation of pumped concrete. Pumping concrete requires long-distance transportation and construction under high temperature conditions, which will inevitably le...

AI Technical Summary

Problems solved by technology

Although reactive polymers are very effective in solving the problem of concrete slump, they also have fatal shortcomings. Its storage stability is poor, and its plastic retention effect decreases with the prolongation of storage time. Synthesized in a solvent, which is very polluting to the environment and is not conducive to sustainable development

[0009] At present, the new type of carboxylic acid graft copolymer superplasticizer has become a worldwide research hotspot due to its good dispersibility, strong slump retention ability, and many variable factors in molecular structure. However, from the perspective of China's national conditions, Carboxylic acid water reducers are basically foreign products, the price is too high, it is difficult to promote and apply quickly and in a large area. For a long period of time in the future, large-scale construction projects in China will basically be based on naphthalene-based water reducers. Therefore, how to effectively control its slump loss will be a major issue that must be solved in the further promotion and application of high-efficiency water reducers and the development of new technologies for concrete.

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