Reducing-type polycarboxylate superplasticizer and preparing method thereof

Abstract

The invention discloses a reducing-type polycarboxylate superplasticizer and a preparing method thereof. The polycarboxylate superplasticizer is obtained by copolymerizing alkenyl polyether macromonomer, acrylic acid, maleic acid monoalkyl ester and maleic acid polyoxyethylene/polyoxypropylene polydimethylsiloxane ester under the condition of the existence of an initiator and a chain transfer agent and in an aqueous solution with the temperature being 20 DEG C-80 DEG C. The reducing-type polycarboxylate superplasticizer has a good reducing effect under a low admixture dosage; meanwhile, the reducing-type polycarboxylate superplasticizer has a certain water reducing capability and a small influence on the intensity of concrete, and is excellent in performance.

Description

technical field [0001] The invention belongs to the technical field of building admixtures, and relates to a shrinkage-reducing polycarboxylate water reducer based on cement-based materials and a preparation method thereof. Background technique [0002] The shrinkage and cracking of mortar and concrete has always been a troublesome problem in construction engineering. This is mainly caused by the drying shrinkage and plastic shrinkage in the hardening process of concrete. At present, the shrinkage of concrete is mainly reduced by adding expansion agents in the market. However, it is not easy to control the amount of expansion agent, and too much amount will cause other engineering quality problems. [0003] The research on the shrinkage mechanism of concrete in the past few decades believes that the change of cement stone capillary tension mainly affects the shrinkage of concrete, so a series of shrinkage reducing agents with low surface tension have been developed. For exam...

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Problems solved by technology

[0002] The shrinkage and cracking of mortar and concrete has always been a troublesome problem in construction engineering. This is mainly caused by the drying shrinkage and plastic shrinkage in the hardening process of concrete. At present, the shrinkage of concrete is mainly reduced by adding expansion agents in the market. However, it is not easy to control the amount of expansion agent. Excessive amount will cause other engineering quality problems.

[0003] The research on the shrinkage mechanism of concrete in the past few decades believes that the change of cement stone capillary tension mainly affects the shrinkage of concrete, so a series of shrinkage reducing agents with low surface tension have been developed. For example, patent CN101925554B discloses ( Poly)alkylene compound, which has a certain shrinkage reduction effect, but the dosage is relatively high, and has a certain influence on the strength of concrete; patent CN102112412B reports polyether polyol alkane compounds containing polyoxyalkylene groups, and the dosage is relatively high , and the cost is also high; pure shrinkage reducing agent has high dosage, which affects the fluidity and strength of concrete. Crack-resistant graft copolymer concrete superplasticizer and its preparation method, but organic solvents and organic water-carrying agents are used in the preparation process, the process is complicated, energy consumption is high, and it is not environmentally friendly; patent CN103724567B discloses a shrinkage reduction Type water reducer and synthesis method thereof, after esterification of diethylene glycol monomethyl ether or diethylene glycol monomethyl ethyl ether with low surface tension and acrylic acid or methacrylic acid, methoxypolyethylene glycol, or methylol acrylamide Polymerization, the process requires high temperature, and the long esterification time is not conducive to large-scale industrial production

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