Ceramics-Silikáty 43, (1) 29 - 33 (1999)

In the present work calcium acetate is used as accelerator and water reducer for the silica fume blended cement. The blended cement was prepared from 80 wt.% of ordinary Portland cement and 20 wt.% of silica fume. The dosages of calcium acetate were 0.0, 1.0, 2.0 and 2.5 wt.%. The water of consistency, and the times of initial and final set were determined. The rate of hydration was established by determining the content of free lime, that of chemically combined water, apparent density, total porosity and compressive strength of the hardened cement pastes. Calcium acetate acted as plasticizer, reducing the water of consistency of the blended cement pastes. It also shortened the times of initial and final set, reduced the content of free lime and increased the content of chemically bound water. The compressive strength increased with additions of calcium acetate up to 2.0 wt.% (the optimum), while higher additions caused the strength to decrease.