Title: Influence of Binder Composition on Chloride Penetration Resistance of Concrete

Author(s): P. F. McGrath and R. D. Hooton

Publication: Symposium Paper

Volume: 170

Issue:

Appears on pages(s): 331-348

Keywords: Chlorides; concretes; diffusion; fly ash; mortars (materials); silica fume; slags.

DOI: 10.14359/6829

Date: 7/1/1997

Abstract:
Choosing the optimum cementing material system is a key question when designing a concrete structure to last for a long time in a chloride environment. There is a lack of reliable comparative information on the short and long term performance of cementing material blends, incorporating materials such as silica fume, fly ash and slag. In this contribution, various cementing material blends are examined for their potential ability to resist chloride ion penetration. A range of mixtures was tested to assist designers in material selection for concrete in a chloride environment. Silica fume, blast furnace slag, Class C and F fly ash were examined at 0.30 and 0.40 water to cementing materials ratios (w/cm) for mortars and concrete. Ternary blends of normal portland cement/slag/silica fume and normal portland cement/slag/fly ash were also tested. The diffusion coefficients were determined by chloride migration using a D.C. potential gradient, and by chloride pending/profile grinding. Silica fume was found to be essential to obtain low diffusion coefficients particularly at an early age. Some additional reduction in diffusion coefficient is obtained with ternary blends of silica fume plus slag or silica fume plus Class F fly ash.