The objective of this in-situ concrete frame building project at Cardington was to re-engineer the business process of such buildings in order to reduce costs, increase speed and improve quality. A full scale seven-storey in-situ advanced reinforced concrete building frame designed to Eurocode 2 by Buro Happold was constructed in the BRE Cardington laboratory encompassing a range of different concrete mixes and construction techniques. This provided a focus for a number of construction-phase research investigations. The one described here (task 6) was concerned with early age acceptance of concrete. 94 pages.