Title:
Effect of Mixture Composition on Washout Resistance of Highly Flowable Underwater Concrete
Author(s):
Kamal H. Khayat and Mohammed Sonebi
Publication:
Materials Journal
Volume:
98
Issue:
4
Appears on pages(s):
289-295
Keywords:
admixture; fly ash; granulated blast-furnace slag; silica fume; slump; water-reducing admixture (high-range).
DOI:
10.14359/10397
Date:
7/1/2001
Abstract:
The underwater casting of relatively thin lifts of concrete in water requires the proportioning of highly flowable concrete that can resist water dilution and segregation and spread readily into place. An investigation was carried out to determine the effects of anti-washout admixture concentration, water-cementitious materials ratio, and binder composition on the washout resistance of highly flowable concrete. Two main types of antiwashout admixtures were used: 1) a powdered welan gum at concentrations of 0.07 and 0.15% (by mass of binder); and 2) a liquid-based cellulosic admixture with dosages up to 1.65 L /100 kg of binder. The water-cementitious materials ratios were set at 0.41 and 0.47, corresponding to high-quality underwater concrete. Four binder compositions were used: a standard Canadian Type 10 cement, the same cement with 10% silica fume replacement, the cement with 50% granulated blast-furnace slag replacement, and a ternary cement containing 6% silica fume and 20% Class F fly ash. The concentrations of anti-washout admixture have direct impact on washout resistance. For a given washout loss, greater slump flow consistency can be achieved with the increases in anti-washout admixture concentration and decreases in water-binder ratio. The washout mass loss can be reduced, for a given consistency, when the ternary binder or 10% silica fume replacement is used.