DYNAMIC MODULUS PROPERTIES OF ASPHALT RUBBER MIXTURES

The main objective of this research study was to evaluate material properties of typical Asphalt Rubber (AR) mixtures used by the Arizona Department of Transportation (ADOT). The AR mixtures have been showing remarkable performance in the field over at least two decades. The research plan goal involves characterizing AR mixes in order to determine their properties for future use in the AASHTO 2002 Pavement Design Guide. The 2002 Design Guide uses the Dynamic Modulus as an important material property, which can be obtained either by laboratory tests or using predictive equation. Currently, several AR mixtures are being tested in an unconfined state of stress and also using different levels of confinements. Some of these test results are presented in this paper. The results were also compared with conventional mixes tested at Arizona State University (ASU). The performance of these mixes was also evaluated by comparing them to mixtures of known field performance.