ABSTRACT
Civil engineers are responsible for the production, transport, placing, compacting and curing of fresh concrete. This chapter considers the properties when freshly mixed, between placing and setting, and during the early stages of hydration. Experience in mixing, handling and placing fresh concrete quickly gives concrete workers (and students) a subjective understanding of the behaviour and an ability to recognise 'good' and 'bad' concrete. Rigorous measurement of the flow behaviour of any fluid is normally carried out in a rheometer or viscometer of some sort. A large number of simple but arbitrary tests for consistence or workability have been devised over many years, some only being used by their inventors. In the Vebe test, the response of the concrete to vibration is determined. The flow table test was devised to differentiate between high workability mixes. Although concrete remains sufficiently workable for handling and placing for some time after it has been mixed, its consistence continually decreases.
