Multi-Scale Characterization of Asphalt Aggregates: Linking Lithological Origin, Engineering Performance, and Stripping Resistance

Featured Application: The proposed lithology-based multi-scale framework can support asphalt aggregate selection by integrating mechanical durability, inferred binder–aggregate interaction potential, moisture susceptibility, stripping resistance, and hydrated lime response under different lithological conditions. This study investigates how lithological origin influences the engineering performance, stripping resistance, and multi-scale material characteristics of aggregates used in asphalt pavement applications. Three representative aggregate systems—carbonate limestone from Cebeci (Istanbul), siliciclastic sandstone from Arnavutköy (Istanbul), and mafic volcanic basalt from the Karatepe Formation (Çorlu, Tekirdağ)—were comparatively evaluated. The experimental program included physical and mechanical tests, X-ray diffraction, inductively coupled plasma optical emission spectroscopy, inductively coupled plasma mass spectrometry, thin-section petrography, and stripping resistance testing. Physical, mechanical, and durability test results were evaluated using replicate measurements and are reported as mean ± standard deviation where applicable. Basalt showed the best mechanical and durability performance, with the lowest flakiness index, Los Angeles abrasion value, and magnesium sulfate soundness loss, but exhibited the lowest unmodified retained coating. Limestone showed a higher inferred binder-affinity potential, interpreted from its calcite-dominated mineralogy, whereas sandstone displayed higher sensitivity related to particle shape, mineralogical heterogeneity, phyllosilicate-bearing components, and petrographic pore/microvoid characteristics. The addition of 0.5% CL 90 S hydrated lime produced an intermediate improvement in stripping resistance, increasing retained coating values to 75–80% for all aggregates, whereas 1.0% hydrated lime further improved retained coating to 80–85%. Higher lime contents of 1.5% and 2.0% did not provide additional improvement under the applied laboratory conditions. These results indicate that 1.0% CL 90 S hydrated lime represents the most effective dosage among the tested conditions. Overall, the results demonstrate that aggregate performance is governed by coupled lithological controls involving mineralogy, petrography, geochemistry, inferred surface-related interaction potential, mechanical durability, stripping resistance, and anti-stripping additive response. The proposed framework should therefore be interpreted as a comparative multi-scale assessment rather than a direct predictive model.