A Method to Estimate the Rheological Properties of Aged Asphalt Binders without Actually aging them

Asphalt binder stiffens due to aging during the mixing and lay down operations as well as during the service life of the pavement. The aging processes in the field have been simulated in the laboratory through the use of accelerated test procedures and tracked through rheological characterization of the aged asphalts. However, the laboratory aging procedures along with the rheological characterization of the aged samples are time-consuming processes. Some researchers have been seeking methods to shorten the time involved in generating this information, while others have been suggesting improvements in the test procedures to get reproducible and reliable data, and still others are attempting to find the procedures that would give information in the laboratory that is closer to the reality in the field. In all cases, it is the rheological properties of the aged binders that are used for characterizing the extent of aging. The present work is a step in the same direction but chooses a different approach. A method is proposed to shorten the time involved in generating the information on the aged binder rheology. The suggested procedure aids in estimating the rheological properties of aged asphalts without actually going through the aging process. In order to establish the procedure, rheological data on unaged asphalts are compared with rheological data on aged samples after the Rolling Thin Film Oven Test (RTFOT) and Pressure Aging Vessel (PAV)-aging. It is shown that estimates of the specification temperatures based on the high and intermediate temperature rheological properties of the aged asphalts can be obtained without actually aging the binders in the laboratory. By eliminating the laboratory aging procedures to obtain rheological properties of the aged asphalts, there is a great saving in time and the information is obtained rapidly.