Comparing Laboratory Conditioning Protocols to Longer-Term Aging of Asphalt Mixtures in the Southeast United States

Abstract

This paper uses mixture tests on cores from a full-scale and untrafficked test section to evaluate mixture conditioning protocols intended to simulate asphalt mixture damage experienced from non–load-associated environmental factors. Seven protocols were evaluated against up to 5 years of aging in a hot climate. After matching conditioning protocols to field aging with multiple mixture tests, this paper places secondary emphasis on selecting a suitable mixture test to detect mixture damage caused by non–load-associated environmental factors or laboratory damage mechanisms (i.e., oxidation, moisture, and volume change by freeze-thaw cycles). The data suggest that Cantabro mass loss was appropriate for pairing conditioning protocols to field aging and that 5 days of oven oxidation at 85°C in compacted mixtures was the least severe conditioning protocol considered (simulating 0–2 years of field aging). The protocol that conditioned field cores for 5 days of oven oxidation at 85°C followed by 14 days in 64°C water and one freeze-thaw cycle simulated 4–5 years of field aging in Columbus, Mississippi.