This study presents the physical-mechanical characteristics of the concretes (7 compositions) accomplished with 10% fly ash (FA), 10% metakaolin (MK), 10%FA+10%MK, 10% silica fume (SF), 10% SF+10%FA, 10%SF+10%MK additions by substitution of 10% respectively 20% cement. According to the analysis performed on the fresh concrete - density, slump, flow and entrapped air volume, this concrete is  of normal volume mass concretes type. The compressive strengths of the concretes with additions of fly ash, silica fume and metakaolin to 28 days are closely to those of the reference concrete i.e. 55.01 MPa, or even higher. The flexural tensile strengths are higher after longer hardening periods of time, except the 10% FA + 10% MK concrete composition (S-4). The elasticity modulus, for all the studied compositions, has higher values than the minimum allowed value for C35/45 concrete class. The experimental studies showed that the reduction of the cement quantity in the concretes, without altering the properties, is possible by using of some industrial byproducts or wastes (fly ash or silica fume) and fired clay(metakaolin).