ABSTRACT
Abstract Superplasticizers provide spectacular gains in fresh concrete workability. However, the effectiveness o f these products sometimes does not last more than some 10-20 minutes. It is therefore essential, when using such admixtures, to assess not only the initial workability, but also its evolution. BTRHEOM, the new rheometer developed at LCPC, is especially suitable for doing this job with only one 7-litre specimen. The quantification o f the friction of the seal between container and rotating part is first pre sented. A model is built which allows to deduce from bulk measurements the contri bution o f concrete to the apparent rheological properties.
