Study on the impact of field-simulated short-term aging on crack resistance performance of porous ultra‑thin overlay mixtures

Porous Ultra-Thin Overlay (PUTO) mixtures using high-viscosity modified asphalt require substantially higher mixing and paving temperatures than conventional asphalt mixtures. However, the widely adopted short-term aging protocol (163 °C for 2 h) cannot adequately represent the severe thermal exposure and potential construction delays in actual PUTO construction practice. This study investigated the cracking resistance evolution of PUTO mixtures under field-simulated short-term aging conditions (150 °C to 190 °C, aging durations 0 h to 8 h), via IDEAL-CT test combined with rheological characterization of the asphalt binder.. Results reveal a transition region around 170 °C: below this temperature, mixture behavior is dominated by oxidative hardening, while above it, cracking performance deteriorates severely with intensified aging damage.. The evolution of CTIndex with aging time can be well described by a unified exponential decay model, y = Ae−Bx. Further analysis suggests a decoupled interpretation of the model parameters: Parameter A reflects the initial cracking-resistance potential of the mixture and is mainly related to mixture design, while Parameter B characterises aging sensitivity and is primarily governed by temperature within the tested system. These findings confirm that increasing asphalt film thickness enhances initial performance reserve, while strict construction temperature control is essential to mitigate aging-driven deterioration..