The complex factors during the asphalt production process and subsequent traffic loading, climatic and weather conditions lead to a decrease in durability of asphalt thereby reducing pavement surface service life. The physical and mechanical properties of asphalts change over time and are different than at the beginning. The paper focuses on the laboratory research on effect of thermo-oxidative aging (short term and long term), ultraviolet radiation and water on stiffness and indirect tensile strength of asphalt mixtures. Experimental measurements were performed with different asphalts in terms of mix type (asphalt concrete AC, stone mastic asphalt SMA) and composition (paving grade bitumen 50/70, polymer modified bitumen PMB45/80-75, coarse aggregate andesite and granodiorite). The stiffness modulus at different temperatures (10, 20 and 30oC) using the indirect tension method and indirect tensile strength have been evaluated in relation to the degree of aging, water and UV radiation. The experimental analysis showed a significant increase in the stiffness of polymer-modified asphalt with increasing aging intensity. Exposure to ultraviolet radiation adds to an increase of 35 to 40% in stiffness for unaged PMB asphalt and 12 to 17% for short-term aged mixtures. Accelerated water conditioning reduced the indirect tensile strength of asphalt by an average of 9%, significant in long-term aged samples using the loose mixture method (9 to 17%). The indirect tensile strengths for dry and wet conditioning showed greater changes due to the degree of aging. An understanding of the changes in asphalt properties during design allows for predicting asphalt surface behaviour after a period of use.

aging; asphalt; stiffness