ABSTRACT
In order to determine how silica fumes-compacted, non-compacted and in water suspension (slurry)—affected the consistence of a high performance concrete mix, a series of approximately twenty mixtures were prepared under laboratory conditions. The series included two cements of low alkali type and with low contents of C3A. The investigation also included three different mixing successions. The properties of the fresh concrete were measured by a slump and with a BML-type series 2 concrete viscometer, over a time domain of 5 to 60 minutes. The results indicate that silica slurry yields the most favourable consistencies if the properties of the concrete in fresh state are characterised in terms of slump, yield value and viscosity. The mixing procedure giving cement the best possible prospect to dispere in the paste phase, proved to be the most favourable. The choice of cement affected the consistencies in a conspicuous way. The more finely ground P 400 resulted in a significantly higher yield value in the mixtures and lower slump values.
