Structural Characterization and Life Cycle Assessment of Conventional and Rejuvenated Cold Recycled Mixtures at the NCAT Test Track

Abstract

With growing interest in replacing conventional asphalt concrete (AC) mixtures on low volume roads, cold recycling mixtures incorporating 100% reclaimed asphalt pavement (RAP) have gained significant attention. Recent advancements include the use of engineered emulsions, polymer-modified emulsions, and rejuvenators to enhance cold recycling performance. This thesis focuses on the structural characterization and environmental evaluation of both conventional and rejuvenated Cold Central Plant Recycling (CCPR) mixtures. Five test sections were constructed on an off-ramp at the National Center for Asphalt Technology (NCAT) Test Track in 2021 to assess field performance. Structural characterization of CCPR mixtures was conducted using four approaches: effective structural number, modulus correlation, field performance data, and empirical design charts. Results showed that conventional CCPR mixtures exhibited higher structural layer coefficients (0.41–0.45) than rejuvenated CCPR mixtures (0.28–0.34). These values were assessed using the AASHTOWare Pavement ME Design software, incorporating mix-specific dynamic modulus and calibrated rutting transfer functions. Simulated rutting at design life confirmed the accuracy of the derived coefficients. Additionally, a comparative Life Cycle Assessment (LCA) was performed to evaluate the environmental impacts of the CCPR sections relative to a conventional AC control section. While all CCPR sections demonstrated a 38–62% reduction in global warming potential (GWP), some impact categories such as smog formation and ozone depletion potential were elevated in rejuvenated mixes, primarily due to the rejuvenators used