Title:
Effect of Polycarboxylate Superplasticizer on Contribution of Interfacial Transition Zone to Electrical Conductivity of Portland Cement Mortars
Author(s):
Guodong Xua and J. J. Beaudoin
Publication:
Materials Journal
Volume:
97
Issue:
4
Appears on pages(s):
418-424
Keywords:
high-range water-reducing admixture; sand; water-cement ratio
DOI:
10.14359/7403
Date:
7/1/2000
Abstract:
The effect of a polycarboxylate high-range water-reducing admixture on the electrical conductivity and interfacial transition zone characteristics of portland cement mortars was evaluated using AC impedance spectroscopy, mercury intrusion porosimetry, and two electrical conductance models: the interfacial excess conductance and Bruggeman’s asymmetrical effective medium theories. Mechanical tests were also performed. Mortar specimens used had sand-cement ratios (s/c) of 0.5, 1.0, and 1.5; aqueous high-range water-reducing admixture dosages of 0, 0.3, and 0.75% (by mass of cement); and a water-cement ratio (w/c) of 0.35. The results showed that the presence of the polycarboxylate high-range water-reducing admixture had positively modified the interfacial transition zone performance and the microstructural characteristics of the hardened mortars. It was found, however, that this high-range water-reducing admixture reduced the rate of hydration during the first day.