International Journal of Roads and Airports (IJRA) ISSN 2036-2595 [on-line] - http://ijra.univpm.it Physical Hardening: from Binders to Mixtures Augusto Cannone Falchetto 1 , Mihai O. Marasteanu 1 1 University of Minnesota Date received: 30 November 2010 _______________________________________________________________________________________________________________ Abstract. The significant effect of physical hardening on asphalt binder properties at low tem- perature is well documented. However, there are very few studies addressing physical hardening in asphalt mixtures. This paper investigates physical hardening effect on asphalt mixtures creep behavior at low temperatures. Bending Beam Rheometer (BBR) creep tests were performed on asphalt binder and asphalt mixture beams conditioned at the test temperature for 1h and 24h to quantify physical hardening effects. Both laboratory-prepared and field samples were used. For all asphalt binders, the additional conditioning time resulted in significant increase in creep stiffness and in significant reduction in m-values. For asphalt mixtures, much less significant changes are observed, and the type of aggregate appears to be significant. A semi-empirical model is used to predict asphalt mixture creep stiffness from binder creep stiffness to better understand the role played by the aggregate matrix in physical hardening. Keywords. Asphalt Binder, Asphalt Mixture, Bending Beam Rheometer, Physical Hardening, Hirsch Model This work is licensed under the current Creative Commons Attribution-Noncommercial License.  Corresponding Author, canno125@umn.edu v. 1, n. 1 (2011) 18-34. doi:10.5568/ijra.2011-01-02.1834