This paper presents the results of experimental investigations witch have been conducted to determine the characteristics of strength and durability of concrete prepared with a cement with a high addition of slag, type CEM III/A 32.5R. The results were used to establish, on an experimental way, the applications of blended cements according to the rules of SR EN 206-1 regarding the composition of concrete on the basis of exposure classes of the concrete. The data obtained, in conjunction with international experience in the field, were the basis for technical Romanian regulations.