A 3D rendering-assisted quantitative evaluation of stripping in recycled asphalt materials

Stripping resistance of recycled asphalt materials is a key factor affecting the long-term durability of pavements, yet conventional methods such as the boiling test (ASTM D3625) remain qualitative and lack spatial quantification. To address this limitation, this study employed an ultrasonic stripping test to simulate dynamic water pressure, combined with Pixel 3D image reconstruction and rendering to systematically evaluate the interfacial adhesion between three typical aggregates and five recycled asphalt systems. The proposed 3D rendering method enabled spatially resolved and quantitative visualization of residual asphalt coverage, offering higher accuracy and reproducibility than conventional 2D image-based methods and adhesion grade–based evaluations. The method was further validated and mechanistically interpreted using contact angle measurements, GPC, and DSR tests. The results demonstrate that this method can clearly differentiate adhesion performance among recycled asphalts incorporating different rejuvenators. After ultrasonic stripping at 60°C for 60 min, soybean oil recycled asphalt shows the best performance, with asphalt retention rates of 96.5% on limestone, 94.51% on diabase, and 85.97% on granite, all higher than tall oil and aromatic oil systems. SBS-recycled asphalt outperforms base asphalt, maintaining an average retention of 90.48% on limestone after 120 min. Contact angle and surface energy analyses confirm adhesion differences among rejuvenators, consistent with 3D rendering outcomes. This work provides an effective evaluation method for quantitatively characterizing the stripping resistance of recycled asphalt, providing a reliable approach for accurate interfacial evaluation and material optimization.