Superplasticizers chemical types

Abnormal retardation of superplasticized mixes The factors responsible for extended retardation of superplasticized mixes are closely related to the Blaine surface area and to the chemical composition (mainly the C3A content) of the cement used to produce it it is also dependent upon the SP dosage, the prevailing ambient and concrete temperature. Low-C3A cements like Type V are susceptible to extension of their set even at dosages that are considered normal for other cements with higher C3A. contents [125, 137, 139]. 

Silica fume which is a by-product in the manufacture of ferrosilicon was used as a dispersant for carbon fibers in all the mixes. The chemical and physical properties of the silica fume is listed in Table 1. Polycarboxylie acid-type superplasticizer and hydroxy propyl methyl cellulose (HPMC, viscosity 3500-5600mPa s at 20°C as 2% aqueous solution) were employed as chemical admixtures. 

Their physical properties are listed in Table 4. FA and SF were also used as mineral admixtures. The physical properties of each admixture are listed in Table 5 and 6. For the chemical admixtures, polycarboxylate-based superplasticizer and negative ion type AE agent were used. 

Yamada K, Takahashi T, Hanehara S, MatsuhisaM. Effects of the chemical structure on the properties of polycarhoxylate-type superplasticizer. Cement Concrete Res 2000 30 197-207. 

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