Title: Physicochemical Mechanism of the Action of the Naphthalene Sulfonate Based Superplasticizers on Silica Fume Concretes

Author(s): M. Buil, P. Witier, F. de Larrard, M. Detrez, and A. M. Paillere

Publication: Symposium Paper

Volume: 91

Issue:

Appears on pages(s): 959-972

Keywords: adsorption; mortars (material); naphthalene sulfonate; plasticizers; silica; workability; zeta potential.

DOI: 10.14359/10106

Date: 2/1/1986

Abstract:
The adsorption of a naphthalene sulfonate formaldehyde (NSF) superplasticizer on the surface of a silica fume (SF) has been studied by adsorption isotherms and zeta potential measure-ments. A model is proposed for the fixation of NSF on a SF surface in the presence of cement, which can explain the high efficiency of this type of superplasticizer on the Portland cement - SF - Water system. The rheological efficiencies of several SF have been eva-luated by the determination of the water content of one fresh SF mortar composition at a constant workability. An hypothesis is suggested for explaining the higher water demands by the five silicon or ferro-silicon SF tested in this study, compared to a zirconia SF.