Effects of warm mix asphalt additives on performance properties of polymer modified asphalt binders
This study presents an experimental evaluation for the performance properties of polymer modified asphalt (PMA) binders containing warm mix asphalt (WMA) additives. The PMA binders with the additives were produced using two of the available warm asphalt processes (i.e., Aspha-min and Sasobit) and three PMA binders graded as performance grade (PG) 76-22. The warm PMA binders were artificially short-term and then long-term aged using the rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were carried out on the binders through the rotational viscometer (RV), the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). In general, the results of this research indicated that (1) the addition of the WMA additives into the PMA binders showed positive effects on increasing rutting resistance at high temperature (based on the high failure temperature values from the DSR test); (2) the PMA binders containing the additives were observed to be less resistant to fatigue cracking at intermediate temperatures compared to the control PMA binders (based on the G*sin δ values at 25 °C from the DSR test); and (3) the addition of wax additive represented a possible lower resistance on low temperature cracking (based on the stiffness and the m-value at –12 °C from the BBR test).