This paper investigates the possibility of developing low temperature limit criteria for asphalt mixtures, similarly to what is currently available in the standard specification for asphalt binder. The investigation is based on extensive experimental work that includes Bending Beam Rheometer (BBR) creep tests on asphalt binders and asphalt mixtures at low temperature and on semi-empirical Hirsch model, and on the rheological model proposed by Christensen, Anderson and Marasteanu (CAM). Limiting asphalt mixture creep stiffness values are predicted from Pressure Aging Vessel (PAV; Long term aging) binder creep stiffness data and are next compared with results available in literature. Then, BBR creep data for Rolling Thin-Film Oven Test (RTFOT; Short term aging) asphalt binder are used to predict creep stiffness of the corresponding short term aged asphalt mixtures. Based on these results, a range of limiting stiffness values is obtained. Due to large variations in the calculated slopes of the mixture creep stiffness curves, a limiting value for the relaxation parameter m-value could not be recommended.
Bibliographical noteFunding Information:
This research was sponsored by Federal Highway Administration National Pooled Fund Study TPF 5(132). This support is gratefully acknowledged. The results and opinions presented are those of the authors and do not necessarily reflect those of the sponsoring agencies.
- BBR creep test
- CAM model
- Hirsch model
- creep stiffness
- limiting criteria
- low temperature cracking