“…Both the set acceleration caused by the silica fume and the set retardation caused by the superplasticizer correlate with the reported effects of these materials on the rate of cement hydrationÐthat is, silica fume accelerates, and superplasticizer retards the rate of hydration of the cement. 5,6 Whereas the foregoing experimental findings 4 compared the setting behaviour of mixtures with fixed cement content with and without silica fume and superMagazine of Concrete Research, 2000, 52, No. 5, Oct., 345±352 plasticizer, this paper adds new data in which silica fume is used to partially replace cement at various levels, while varying superplasticizer dosage to maintain workability.…”