Deformation mechanisms of pure bitumen

Experimental data for pure bitumens and simplified theoretical models for their deformation behavior are assembled into a single framework that summarizes their steady-state inelastic response to stress. A number of regimes are identified: a low temperature elastic regime, a low temperature plastic regime, a power-law creep regime, and a Newtonian flow regime. Data for a number of pure bitumens are fitted to constitutive equations for each regime. The equations are then used to construct deformation mechanism maps for a particular type of bitumen commonly used in pavement construction in the U.K. These maps relate strength to temperature and strain rate over a wide range of these variables.