Cement concrete superplasticizer and method for preparing same

Abstract

The invention discloses a concrete superplasticizer and a preparation method. Based on weight proportion, 1-50% of nitrogen-containing functional monomer a, 5-50% of unsaturated carboxylic acid and the derivative b of the unsaturated carboxylic acid, 15-94% of polyoxyethylene vinyl propionate ester ene single-ether and the derivative c of the polyoxyethylene vinyl propionate ester ene single-ether, as well as 0-50% of allyl sulfonate d are mixed to prepare a mixed monomer solution; the initiator which takes up 0.5-15% of the total weight of the mixed monomer, and the chain transfer agent which takes up 0-15% of the total weight of the mixed monomer are added into the mixed monomer solution so as to prepare the concrete super plasticizer through ternary or quaternary copolymerization. Without going through analysis purification, the invention can directly obtain the product and has simple synthetic process, less equipment investment, simple operation and easily controlled reaction conditions; the obtained product has better compatibility with cement and good adaptability with other additives, and is free from segregation and bleeding phenomena; the product also has good concrete slump retentivity and high water reduction rate.

Description

technical field [0001] The invention relates to a cement concrete superplasticizer. [0002] The invention also relates to a preparation method of the cement concrete superplasticizer. Background technique [0003] Cement concrete is the most common building material, and the concrete mixture should be kept in a fluid state before casting to enhance workability and workability. However, today's concrete faces the problems of short concrete processing time and poor workability. At the same time, after long-term mixing, concrete often segregates, bleeds, and even cannot be cast. In order to solve the above problems, early concrete admixtures mostly used polymers such as lignin sulfonate, naphthalene sulfonate formaldehyde condensate NSF, melamine sulfonate formaldehyde condensate MSF, aliphatic sulfamic acid ASPF, etc. Under the premise of changing the workability of concrete, the water consumption of concrete mixing can be greatly reduced, and the strength of concrete can b...

AI Technical Summary

Problems solved by technology

[0007] US4814014: Prepared by grafting method, but the problem is that there are a large number of non-grafted and homopolymers in the copolymer, so the product conversion rate is low, the cost is high, and the effect is poor

If the amount is too high, precipitation, dispersion and dispersion retention are not good

[0020] At home and abroad and in the literature, it is mentioned that the polymerization method for preparing polymers generally adopts a two-step method or a grafting method. The two-step method is more complicated to prepare the production process, and the reaction conditions are harsher and difficult to control, especially the preparation of the first step product. The obtained product contains too many impurities, which greatly affects the second-step polymerization reaction

Long production time, many restrictions, low efficiency, complex influencing factors, difficult to control the purity of intermediates, and some of the above preparation methods are carried out in organic solvents, which is not conducive to clean production and environmental protection

It also complicates the process, increases the cost, and brings inconvenience to production and use.

The polycarboxylate superplasticizer prepared by the two-step method has relatively large fluctuations in water reducing rate, poor adaptability to cement, poor compatibility with other admixtures, and poor temperature stability

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