Regularities of Hydration and Structure Formation of Cement Pastes in the Presence of Superplasticizers with Different Molecular Mass
A. I. Vovk, G. A. Vovk and A. V. Usherov-Marshak
Appears on pages(s):
Adsorption; clinker; hydration; superplasticizers; thermal properties
Results describing investigations of the kinetics of hydration and struc-ture formation of cement systems (C3 S, C3 A, C3 A + gypsum, and portland ce-ment) in the presence of naphthaleneformaldehyde type superplasticizers (SNF ) of different compositions are discussed Using the individual components of SNF sodium polymethylenenaphthalenesulfonates ( PNS ) with polycondensation degrees ranging from 2 to 17, the basic dependences of the kinetics of the processes on the average molecular mass of the admixture ( Mn were shown In the case of C3 S the retarding effect of SNF on hydration and structure formation processes depends lineally on Mn , as a general rule, whilst for C3 A the retarding effect is more pronounced for mid-condensated components of superplasticizer. This difference is due to the different adsorption mechanism of the superplasticizer on the above-mentioned minerals. The unusual form and the analogy of ther-mokinetic curves for C3 A and C3 A - gypsum hydration in the presence of PNS are the first experimental proof that organic-mineral compounds are formed in these systems.