Polycarboxylic acid water reducing agent suitable for machine-made sand and preparation method of water reducing agent

Abstract

The invention relates to a polycarboxylic acid water reducing agent suitable for machine-made sand and a preparation method of water reducing agent. The polycarboxylic acid water reducing agent is synthesized by adopting an aqueous solution free radical polymerization method according to the following proportion by mass: 200 parts of polyether macromonomer; 15.0 to 30.0 parts of acrylic acid; 5.0 to 12.0 parts of DNS-86; 300 parts of distilled water in total ; and an initiator including 18 to 35 parts of hydrogen peroxide and 6.0 to 12.0 parts of Vc by mass. The reaction temperature is controlled to be 10-35 DEG C. The water-reducing agent has the characteristics of high wettability, small slump loss, high water-reducing rate and early strength, and has the advantages of easily available preparation raw materials, low cost, large-scale production and the like.

Description

technical field [0001] The invention relates to the technical field of construction engineering materials, in particular to a polycarboxylate water reducer suitable for machine-made sand and a preparation method thereof. Background technique [0002] With the continuous consumption of high-quality sand and gravel resources in our country, the use of machine-made sand is an inevitable trend. Machine-made sand is obtained by mechanical crushing of rocks. Machine-made sand is obtained by crushing. The surface is sharp and angular, with a large amount of fine powder, and the surface is moist Water reducers, especially polycarboxylate water reducers, have always had problems such as large loss and poor adaptability, resulting in low water reducing rate and insufficient slump retention performance. At present, the problems of large concrete loss and poor adaptability caused by machine-made sand have not been well resolved. [0003] CN201810273310.9 reports a polycarboxylate water...

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Problems solved by technology

However, the polycarboxylate superplasticizer still has problems such as poor wettability and poor encapsulation of machine-made sand;

[0004] CN106749963A discloses an air-entraining controllable polycarboxylate water-reducer for pure machine-made sand concrete and a preparation method thereof, in which an alkylphenol polyoxyethylene ether monomer and an unsaturated carboxylic acid monomer are esterified reaction to generate unsaturated carboxylic acid-alkylphenol polyoxyethylene ether ester monomer, and then perform aqueous copolymerization reaction of unsaturated carboxylic acid monomer, unsaturated polyether monomer and unsaturated sulfonic acid monomer to obtain Air-controllable polycarboxylate water-reducer, the water-reducer prepared by it is used in pure machine-made sand concrete, and has the advantages of high water-reducing rate, good adaptability, small bubble diameter, stable sealing, and controllable air-entrainment. , but its macromonomer nonylphenol polyoxyethylene ether can only play a certain role in wetting and regulating after hydrolysis, especially on the wrapping and water reducing rate of initial concrete sand and gravel.

[0005] CN108409193A discloses a preparation method of a polycarboxylate admixture for machine-made sand ultra-high-strength concrete. It can effectively improve the machine-made sand ultra-high-strength concrete due to the poor gradation of the machine-made sand itself and the poor particle shape. It can meet the requirements of pumping construction for super high-rise buildings, but it has limited effect on improving wettability and early strength.

[0006] CN109627394A discloses a polycarboxylate concrete water reducer suitable for machine-made sand and its preparation method, which has achieved good results, but the key functional monomer used in its preparation, i.e. 2-acrylamido dodecyl Due to the small range of uses, small output, high price, complex synthesis process and the use of fuming sulfuric acid, dodecene, etc. in the synthesis, sulfonic acid causes pollution and serious corrosion of equipment, which affects its promotion and use.

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