Properties of Fresh Concrete

Abstract

The last RILEM Seminar on the Technology of Fresh Concrete took place in 1973 in Leeds. The main interest of this seminar was focused on workability, measuring techniques and the use of additives. In the meantime nearly two decades have passed. During this period, considerable changes have taken place in concrete production. In many countries concrete production has been shifted from the site to the plant almost completely. This development presents new questions for technology, especially how to achieve an exactly defined consistency at the moment of delivery on site, from plant to builder. This problem turned out to be a difficult one, since consistency changes take place during the period between mixing and delivery, not only depending on the duration of transport, but also on other parameters, for example temperature. The development and growth of the ready-mixed concrete industry coincided in many countries with drastic changes in the cement industry: a trend to larger sized furnaces and mills. The new techniques involved also influenced the cement properties and their effect on the workability of fresh concrete. All these developments caused the RILEM Coordinating Committee for Concrete Technology (CCC) to hold a colloquium on the Properties of Fresh Concrete. Members of the scientific committee were