Title: Fly Ash Concrete Mix Design and the Water-Cement Ratio Law

Author(s): Francis A. Oluokun

Publication: Materials Journal

Volume: 91

Issue: 4

Appears on pages(s): 362-371

Keywords: fly ash; mix proportioning; water-cement ratio; Materials Research

DOI: 10.14359/4050

Date: 7/1/1994

Abstract:
When the water-cement ratio law was proposed by Abrams in 1918, the use of fly ash and silica fume as replacements or substitutes for part of the cement was virtually unknown. Consequently, the effects of fly ash and silica fume were not considered in the development of Abrams' law. Since the early 1960s, concrete mix compositions have changed, and cement is no longer the only cementitious material in concrete mixes. In a high percentage of situations, today's cementitious material content is made up of cement plus fly ash. This study investigates the applicability of Abrams' law to concrete mixes containing fly ash. As initially expected, it was found that Abrams' water-cement ratio law is not directly applicable to mixes with fly ash. An alternative augmented water-cementitious materials ratio law is proposed for designing concrete mixes containing fly ash.