Investigation Of Hot Mix Asphalt Aging Effect On Binder Performance

Asphalt roads continuously experience physicochemical changes under the combined influence of oxygen, heat, ultraviolet (UV) radiation, and water. Oxidation increases molecular polarity and association, causes maltenes loss, and continues hardening the asphalt binder, reducing ductility, stress-relaxation capacity, and resistance to cracking (Petersen 1982; Colbert and You 2012). Because aging is a cumulative process beginning at plant production, accelerating during construction/compacting, and continuing in service, the laboratory tests and indices must capture the extent of short-and long-term aging to support performance-related specification and Balanced Mix Design (BMD) (AASHTO R30 2022; Kim et al. 2017). This chapter reviews: (i) laboratory and field-representative aging procedures and their equivalence; (ii) the thin-film effect due to the reasons why mixture-aged binders develop more rapidly than bulk binder; (iii) impacts of reclaimed asphalt pavement (RAP), binder content, gradation, and rejuvenators; (iv) rheo-chemical indices |G*|×sind, Glover–Rowe (G-R), and FTIR-derived carbonyl index (ICO), and their relation with mixture cracking tests like Overlay Test (OT) and IDEAL Cracking Test (IDEAL-CT); and (v) Quality Assurance (QA), BMD, and specifications implications. Where relevant, recent experimental findings from this research are incorporated to complement and update the existing state of knowledge.