ANTI-WASHOUT ADMIXTURE FOR UNDERWATER CONCRETE.

Underwater concreting methods include: concrete bagwork, grouting preplaced aggregate, concrete mixed conventionally, but placed either by tremie pipe or skip, and pumping. Whatever the method adopted. There is always a tendency for cement to get washed away and for the fine aggregate to become segregated from the coarse one. To overcome this problem, experiments were recently carried out by the US Army Corps of Engineers at the Waterways Experiment Station, to evaluate the use of anti-washout admixtures in concrete for underwater repair of stilling basins. This article discusses the test program and results.