Cementless pressed blocks from waste products of coal-firing power station

The effect of altering composition of cementless building materials on basis of waste products of power station including hydrophobic additive and the molding compaction on the compressive strength, water uptake and water absorption was examined. A possibility to get water-stable materials at curing in the ambient air was established. It was shown that water uptake might be reduced by different methods, the best of which is short-term impregnation by a hydrophobic liquid of the siloxane group. Results from experiments with small specimens and full size pressed blocks were compared. It is noted that blocks answered to the requirements of Israeli Standard to cement concrete blocks.