NATURAL CRUSHED ROCK AS AGGREGATE FOR ULTRA HIGH STRENGTH CEMENT CONCRETES

Because of strong competition and new trends of concrete construction, cement industry isstarting to offer cement of high class in world markets (62.5; 72.5; 82.5) with whom production ofultra hard concretes of 100 MPa up to 250 MPa of withstanding is possible. To achieve suchwithstanding, not only cement of high class are needed but also rock aggregates of at least 30% higherrigidity than the required rigidity of concrete. Technological solutions for this kind of concrete will behighly demanded by the cement industry, civil engineering industry and industry for the exploitation ofraw mineral materials. Production of such crushed aggregates will find its use in the production of ultrahigh rigidity concretes and will open new surroundings.This paper offers the overview of tests in laboratories conducted on samples of aggregates made ofgabbro rock under Nero Zimbabwe’s name, as an initial phase of research. In later phases itcovers a larger number of above mentioned samples from various excavation sites, with a specialaccent on these kinds of sites in former Yugoslavia. It is expected that these premises may havereserves of rock aggregate resistant to pressures of 150 MPa to 330 MPa which would openpossibilities of constructing ultra high rigidity concretes.In addition to analyzing the required production of ultra high strength concrete, the authors consciouslypoint out the problem of interpreting the mechanical characteristics of the material. The technicalprofession does not consider the physical state of the investigated materials, where the compressivestrength of concrete is in the form of relative strength. From the aspect of legal sciences, the concept ofrelative at the construction of large and small objects can cause legal consequences for the constructorand its profession.