Regional Variations in the Physical and Rheological Properties of Asphalt Binders Recovered from Earthquake-Damaged Roads Following the February 6, 2023 Türkiye Earthquakes

This study investigates the physical and rheological properties of asphalt binders recovered from earthquake damaged road sections in Hatay, Kahramanmaras, Gaziantep, and Malatya following the February 6, 2023, earthquakes in southern Türkiye (Mw = 7.8 and Mw = 7.5). Asphalt mixture samples were collected from severely deteriorated pavements, and bitumen was extracted through solvent extraction and rotary evaporation. The recovered binders were subjected to penetration, softening point, rotational viscosity, and Dynamic Shear Rheometer (DSR) tests to evaluate aging, stiffness, high-temperature performance, and viscoelastic behavior. Results revealed significant regional differences: Hatay binders exhibited the lowest penetration, highest softening point, highest viscosity, and the greatest rutting resistance (high G*/sinδ values) while maintaining lower phase angles, indicating enhanced stiffness and elasticity. In contrast, Kahramanmaras binders showed the highest penetration, lowest softening point, and lower viscosity, combined with high phase angles, reflecting a softer, more viscous character with reduced deformation resistance. Malatya and Gaziantep binders displayed intermediate characteristics, with Malatya showing moderate stiffness and Gaziantep retaining greater flexibility. Across all samples, viscosity decreased markedly with increasing temperature, and rutting resistance diminished at higher service temperatures; however, binders with higher initial G*/sinδ values retained better performance. The findings highlight the influence of regional seismic intensity, climatic conditions, and pavement history on binder behavior and emphasize the need for region-specific maintenance and rehabilitation strategies in post-disaster pavement management.