Analysis of Reclaimed Asphalt Pavement Heating with Microwave Radiation

The research focuses on the assessment of the potential use of microwave radiation as alternative heating method for reclaimed asphalt pavement (RAP) in hot mix asphalt (HMA) production. Recent studies on the use of microwave radiation in road engineering mostly focused on the cracked asphalt pavement. In the study, microwave heating performance was assessed based on the physical and mechanical characteristics of HMA with different RAP contents containing various amount of moisture. Results were compared to the HMA consisting of high amount of RAP containing Styrene–Butadiene–Styrene (SBS) polymer modified binder. The test results confirmed the possibility of microwaves utilization in order to heat the HMA without adversely affecting its basic properties. The research also shows the possibility of heating RAP in the process of HMA production, especially if the RAP moisture level is above 3%. In addition, the tests on HMA did not reveal any negative impact of microwave heating in the case of using wet RAP for the production of HMA. The susceptibility of the SBS polymer to microwave radiation was indicated by comparing the behavior of the two HMA types under its influence. HMA containing modified bitumen appears to achieve higher temperatures than HMA with unmodified bitumen after the same time of microwave heating.