Statistical Analysis of Long-Term Aging Parameters of Laboratory- and Field-Aged Asphalt Binders Considering Rheological and Chemical Properties

Aging has long been recognized as an important factor that accelerates damage to flexible pavements. This study investigates the effects of long-term aging protocols on critical rheological and chemical parameters in the laboratory and field by focusing on the evaluation of aged binders under various aging conditions. To fabricate aged binders with various long-term aging levels, five laboratory aging protocols were considered, including a standard pressure aging vessel for binder and loose-mix aging protocols (70 degrees C, 85 degrees C, 95 degrees C, and 135 degrees C) with various aging durations. The rheological properties and chemical composition of laboratory-aged binders were extensively evaluated. For comparison, field-aged binders were extracted from 14 top layers and measured in a similar manner. A general linear model statistical analysis was conducted on the relationship between the rheological and chemical parameters to explore the potential differences between various aging protocols. Loose-mix aging in the range of 70-95 degrees was found to be relatively closer to the in situ aging trend using statistical analyses. The results of this work provide a reasonable simulation of long-term-aged in-service asphalt pavement that can assist in material selection, mixture design, and maintenance operations.