Efficiency and performance analysis of electromagnetic heating method in asphalt recycling

Today, increasing industrialization, population growth, and the intensification of economic activities have accelerated the consumption of natural resources, leading to serious waste related problems. In this context, recycling and recovery practices are gaining growing importance to reduce environmental impacts and use existing resources more efficiently. The transportation sector is one of the most resource-consuming and waste-generating sectors. In particular, asphalt pavements used in road infrastructure lose their functionality over time and need renewal, resulting in the generation of large amounts of asphalt waste. The reuse of asphalt layers that have reached the end of their service life holds significant potential both economically and in terms of environmental sustainability. In this thesis, the effects of using reclaimed asphalt pavement (RAP) in asphalt production on the performance of asphalt mixtures were investigated comparatively using different RAP contents and two different heating methods. A total of 24 different mixtures were prepared, containing 0%, 10%, 30%, and 50% RAP. The mixtures were produced using the conventional heating method (CHM) and the electromagnetic heating method (EHM), specifically employing microwave radiation, and the effects of these methods on mixture properties were analyzed in detail. Experimental analyses evaluated the bulk specific gravity, water absorption, stability, flow values, and Marshall quotient of the mixtures. The results showed that EHM provided higher bulk specific gravity, particularly in mixtures containing 10% and 30% RAP, resulting in a denser structure. Moreover, EHM reduced water absorption rates, thereby decreasing the moisture susceptibility of the mixtures, and improved stability by 25–30% at 10% and 50% RAP contents. The observed decrease in flow values indicates that the mixtures prepared with EHM are more resistant to elastic deformation. In terms of the Marshall quotient, EHM also enabled the production of mixtures with greater resistance to deformation. In light of all these findings, it was concluded that asphalt mixtures prepared with EHM performed better than those prepared with CHM in terms of both physical and mechanical properties.