HP-GPC Characterization of Asphalt Aging and Selected Properties

Abstract
Long-term age-hardening behavior of asphalt cements was simulated by the thin-film-oven test procedure with extended oven durations. Seven AC-20 asphalt cements from different crude sources were aged for 5, 14, and 24 h. Testing of selected physical properties (e.g., absolute and kinematic viscosity) and high-performance gel permeation chromatography (HP-GPC) analyses were conducted on the virgin and aged asphalt cements. HP-GPC profiles were partitioned into three, four, and 10 segments (HP-GPC parameters) based on equal elution time. Statistical analysis conducted on HP-GPC profiles indicated that long-term laboratory aging produced significant differences among HP-GPC parameters. It also indicated that significant compositional differences existed among the AC-20 asphalt cement sources. Regression models were developed for predicting physical properties of asphalt cements based on HP-GPC parameters. Strong relationships ( R2 > 0.75) were established between four physical properties and HP-GPC partitions into tenths. Partitioning of chromatograms into 10 segments provided a better resolution of the data than the division into thirds and fourths.