| With the merits of higher fluidity effect and preventing concrete mix from slump-loss with time duration, poly-carboxylic acid series water-reducer agent (WRA) has been widely studying. In this paper, as the raw materials of WRA, a series of poly-carboxylic acid water reducer intermediate macromonomers (PEOO) were synthesized and the optimal raw materials mixture ratio of poly carboxylic acid WRA (PAA) were determined with the help of orthogonal test means. Then the performances were compared, analyzed and evaluated with those of two different kinds of HWRA (UNF-5 and Sika).At last through the studying of surface properties such as surface tension, adsorptive capacity, Zeta potential and so on, discussed the water reducing mechanism. Research showed that PAA had higher initial dispersing property to cement paste than that of inland naphthalene series UNF-5 and abroad poly carboxylic acid series superplasticizer Sika. The dispersing property of PAA bore upon the sulfate ion concentration in the cement; the saturation of PAA in cement paste was about 0.3%; PAA could delay the coagulation of cement paste at a low percentage (0.2%), while it accelerated the coagulation at higher percentage (0.5%). It was founded that chain length and quantity of the intermediate macromonomers PEOO has a decisive effect to the average molecular weight, molecular weight distribution, dispersing and durable dispersing property of the PAA; In the copolymerisation, methyl sodium alkyl sulfonate not only provided strong polar anion sulfonic group but also acted as chain transfer agent; Space steric hindrance resulted by length lateral chain and electrostatic repulsion of charged ion made the main contribution to water-reducing effect of PAA.
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