Title: Chloride Permeability of Fly Ash-Cement Pastes and Mortars

Author(s): D. M. Roy, R. I. A. Malek, and P. H. LicastroI

Publication: Symposium Paper

Volume: 100

Issue:

Appears on pages(s): 1459-1476

Keywords: blended cements; cement pastes; chlorides; diffusion; fly ash; mortars (material); permeability; Materials Research

DOI: 10.14359/2165

Date: 4/1/1987

Abstract:
Results of an accelerated electro-osmosis experiment to determine the effectiveness of different cement/fly-ash blends (cured for 28 days) in resisting chloride ion diffusion are presented. Effects of curing temperature, water-cementitious materials ratio, presence of sand, etc., on the chloride ion migration were determined. Class F fly ashes increase the effectiveness of the blend to resist chloride ion migration at any fly ash replacement level. The effect increases with increasing percentages of replacement. This is possibly due to the strong interactions between Class F fly ash or its reaction products with cement and ionic species in pore fluids. A higher replacement level, on the other hand, is required to significantly decrease chloride ion diffusion in cement/Class C fly-ash blends.