THE EFFECT OF THE CEMENT TYPE AND OF CURING ON THE MASS AND DEFORMATIONS OF HARDENED CEMENT PASTE

We have prepared test cylinders out of three cements significantly different in composition (clean portland cement, cement with 40% blast furnace slag content and cement with 20% fly ash content) changing the water/cement ratio (0.10, 0.15, 0.20) and the stamping force (5, 15, 50, 100 N/mm 2 ). The cylinders were cured under different conditions (air of 50-60% or 95% relative humidity or in lime saturated water), examined the change in length and the mass of them by time and determined their strength at the age of 90 days. Out of the three cement types - stamped under the same conditions - the cylinders with fly ash content had the biggest porosity. The curing method has significantly influenced the change of porosity, mass and deformation of the cylinders by time. The effect of cement type has shown on one hand in porosity and on the other hand especially in the initial deformations of the cylinders the physical and chemical processes during setting (e.g. formation of ettringite).