EXPERIMENTAL STUDY ON THE STRUCTURAL BEHAVIOUR OF ASPHALT MIXTURES EXPOSED TO UV RADIATION

Asphalt mixtures are the most commonly used material in road construction. It is necessary to know the properties of the mixtures and their constituents, as well as the changes in properties that occur during their service life. The demands on road durability are constantly increasing. The main problem with asphalt mixtures is degradation. Due to the effects during asphalt pavement production and service, there is a gradual degradation of properties. One of the degradation factors is the impact of traffic, climate and weather on the road surface. One climatic factor whose influence on pavement degradation has not yet been researched in detail is solar UV radiation. The main cause of ageing is known to be the oxidation of asphalt molecules by oxygen. However, UV radiation also has a photo-oxidation effect on the pavement in service. Oxidation processes cause gradual hardening and embrittlement of the asphalt layer. Understanding these processes could lead to better design of asphalt mixtures and more appropriate material selection to improve performance and extend pavement life. In this article, the results of the measure of the effect of UV radiation on the stiffness changes for AC11 50/70 asphalt mix will be presented. In order to more accurately determine the effect of UV radiation on asphalt mixtures, we used AC11 50/70 mixtures unaged, long-term aged by the loosely distributed mix method, and long-term aged by the compacted specimen method. The modulus of stiffness was measured by the IT-CY laboratory method at 20 C. The monitored changes in the stiffness of the asphalt mixture were exactly 3 times after 200 hours of UV radiation, a totally of 600 hours of UV radiation.