LABORATORY AGING OF ASPHALT-AGGREGATE MIXTURES: FIELD VALIDATION

The hardening or stiffening associated with heating asphalt is referred to as aging and occurs in two stages: short-term aging, which occurs during mixture mixing and placement, and long-term aging, which occurs throughout the life of the pavement. A portion of the Strategic Highway Research Program has been dedicated to developing accelerated performance tests for aging asphalt mixtures. Two test procedures developed at the Oregon State University utilize oven aging at 135 deg C and 85 or 100 deg C to simulate short- and long-term field aging. This report presents the results of the field validation of these two procedures. Continued analysis of the field sites used in this study and selection of additional sites is required to develop prediction models for all combinations of climatic region and asphalt grade. Younger sites would require additional cores to be drilled, possibly in 5, 10, and 15 years, to determine the field moduli at those times.