The effects of different cement dosages, slumps and pumice aggregate ratios on the freezing and thawing of concrete

This research was conducted to determine effect of pumice aggregate ratio, cement dosage and slumps on freeze-thaw resistance, density, water absorption and elasticity of concrete. In the first batch, 300 kg/m3 cement dosage were kept constant and pumice ratios were changed as 25%, 50%, 75% and 100% of replacement for normal aggregate by volume for 3? cm, 5? cm and 7? cm slumps. Other batches were prepared with 200 kg/m3, 250 kg/m3, 350 kg/m3, 400 kg/m3 and 500 kg/m3 cement dosages and 25% pumice aggregate +75% normal aggregate at a constant slump. Test results showed that when pumice-aggregate ratio decreased the density and freeze-thaw resistance of concretes increased. With increasing of cement dosage in the mixtures, density of the concretes increased, however, freeze-thaw resistance of concretes decreased. Water absorption of the concrete decreased with increasing cement dosage but increased with the pumice ratio. Water absorption of the concrete also decreased after freeze-thaw cycles. Freeze-thaw resistance of concretes was decreased with increasing the slumps.