Title: Use of Multicomponent Cementitious Systems in High-Performance Concrete

Author(s): M. D. A. Thomas and M. H. Shehata

Publication: Symposium Paper

Volume: 189

Issue:

Appears on pages(s): 295-310

Keywords: chlorides; diffusion; high-performance concrete; pore size distribution; silica fume

DOI: 10.14359/5858

Date: 1/1/2000

Abstract:
This paper presents data on the performance of concrete containing ternary combinations of Portland cement, silica fume and fly ash. Porosity measurements show that the individual effects of silica fume and fly ash on pore size distribution are cumulative when both materials are added to Portland cement. Chloride diffusion and rapid chorine permeability test on concrete indicate significant improvements can be achieved through the use of these ternary combinations. There is a synergistic effect attributed to the early-age benefits of incorporating silica fume and the long-term improvements normally associated with fly ash. The final product is concrete with very low initial directivity values that continue to reduce with time. Simplistic service-life calculations indicate that high-performance concrete with ternary cementations blends may provide protection to steel reinforcement way beyond the normal expectations of engineers today. These results are not inconsistent with recent studies of marine exposed concretes, which indicate that the penetration of chlorides may eventually decrease to almost insignificant rates in concretes containing 30% to 50% fly ash.