Mechanistic-Empirical Analysis of Asphalt Dynamic Modulus for Rehabilitation Projects in Iran

In the Mechanistic–Empirical Pavement Design Guide (MEPDG), dynamic modulus of asphalt mixes are used as one of the input parameters in pavement analysis and design. For in-service pavements, MEPDG method uses a combination of some field and laboratory tests for structural evaluation of asphalt layers in rehabilitation projects. In this study, ten new and rehabilitated in-service asphalt pavements with different physical characteristics were selected in provinces of Khuzestan and Kerman in south of Iran. These provinces are known as hot climate areas and have sever climatic conditions. At each site, Falling Weight Deflectometer (FWD) testing was conducted and core samples were taken. These samples were extracted and mix volumetric properties and bitumen characteristics were determined. The results of these tests were used as input parameters in Witczak dynamic modulus prediction model for determination of MEPDG undamaged dynamic modulus master curves. Finally, the damaged (in-situ) dynamic modulus master curves were developed upon modifying the undamaged master curves with the damage factors determined from backcalculation analysis of FWD data. It was found that with the above mechanistic-empirical procedure, it would be possible to successfully evaluate in-service asphalt layers located in sever climatic areas.