Mechanistic – empirical calculation method is applied worldwide in calculation of new pavement structures and evaluation of the existing ones. The majority of mechanistic methods of dimensioning is based on the evaluation of the structural behaviour of structures, i.e. critical relation of stress and deformity during application of certain load on the pavement. Stiffness of asphalt mixtures is an essential parameter in evaluation of induced load, temperature stress and distribution of deformities in pavement structure. In certain parts of Croatia the average maximal summer temperatures on pavement surface reach approximately 40°C. At such high temperatures, the asphalt stiffness modulus is significantly decreased and there is a high possibility of occurrence of driving surface plastic flow in the form of rutting. During winter, temperatures decrease to -10°C and the combination of low temperatures and cyclic changes, with very high stiffness modulus, may cause cracks in asphalt pavement. Systematic measurement of asphalt mixture stiffness modulus was carried out within the research through application of the indirect tensile test method at temperatures those mixtures would be exposed to during their project life span. This Paper presents elaboration of stiffness modulus test results achieved through application of the indirect tensile test on several types of asphalt mixtures at different temperatures. Furthermore, it presents the stiffness modulus test results for several asphalt concrete mixtures AC 11 of different composition, i.e. of different physical – mechanical properties.

stiffness modulus; asphalt mixture; indirect tensile test; rutting