http://orcid.org/0000-0001-9018-0719
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Abstract
In this paper, the combined effect of aging temperatures and cooling medium on the rheological properties of asphalt binder was experimentally investigated and evaluated. Two 70/100 penetration grade binders, which were part of the core materials used by the active RILEM committee CMB-252, were selected for this purpose. The materials were artificially aged to six different conditions, first with the Rolling Thin Film Oven Test (RTFOT) at three different temperatures (123°C, 143°C, and 163°C), and then, with the standard Pressure Aging Vessel (PAV). Next, temperature and frequency sweep (T-f-sweep) tests were performed on the entire set of materials by using the Dynamic Shear Rheometer (DSR) from −30°C to 80°C while low-temperature creep tests were conducted on the long-term aged asphalt binders with the Bending Beam Rheometer (BBR) devices in air and in ethanol, respectively. Then, the 2 Spring 2 Parabolic element 1 Dashpot model (2S2P1D) and Huet model were used to evaluate the rheological properties of asphalt binders based on the DSR and BBR results, respectively. Moreover, two parameters, crossover temperature, Tδ=45°, and the difference in critical temperature, ΔTc, were used to evaluate the aging properties of the materials. Finally, the relationship between the time domain complex modulus based on DSR and the creep stiffness obtained with the BBR was established to investigate the effect of the cooling medium at low-temperatures. The results indicate that a temperature reduced process may lead to a mitigation of the short-term aging of asphalt binders, while a temperature reduction of only 40°C can result in a consistently milder long-term aging. In the BBR test, higher creep stiffness and smaller m-values can be observed in the air compared to ethanol. Huet and 2S2P1D models show that complex modulus and creep stiffness share the same core parameters only in the case of air. Based on the finding in this research, the temperature reduced mixing process and the use of air for BBR creep tests are recommended.
Acknowledgements
The RILEM Technical Committee on Chemo-Mechanical Characterization of Bituminous Materials (CMB) 252 is gratefully acknowledged. The authors would also like to thank the China Scholarship Council, National Natural Science Foundation of China (51508064, 51408083) for the financial support to the graduate studies of the first author. The support provided by the laboratory team at the Institut für Straßenwesen, Technische Universität Braunschweig, Germany, and the Japan Society for the Promotion of Science - JSPS for international research in Japan are also acknowledged.
Disclosure statement
No potential conflict of interest was reported by the authors.
ORCID
Di Wanghttp://orcid.org/0000-0001-9018-0719
Augusto Cannone Falchettohttp://orcid.org/0000-0002-3240-6158
Peter Mikhailenko http://orcid.org/0000-0001-6359-2937
Lily Poulikakoshttp://orcid.org/0000-0002-7011-0542
Bernhard Hofkohttp://orcid.org/0000-0002-8329-8687
Laurent Porothttp://orcid.org/0000-0002-7173-9035
Michael P. Wistubahttp://orcid.org/0000-0002-4406-7050