Fatigue Performance Evaluation of Rubberized Porous European Mixture by Simplified Viscoelastic Continuum Damage Model

The study investigated the fatigue performance of rubberized porous
European mix (PEM) and control PEM and the influence introducing
methods of crumb rubber modifier (CRM) on the fatigue performance
of PEM. Four PEM mixtures were used: rubberized PEM in dry process,
rubberized PEM in wet process, rubberized PEM with terminal blend
binder, and control styrene–butadiene–styrene (SBS) modified PEM.
Dynamic modulus and direct tension fatigue tests were performed with
an asphalt mixture performance tester system. The fatigue test data
were analyzed by the simplified viscoelastic continuum damage theory.
There were four main results. First, the rutting resistance of the rubberized
PEM in the dry process was similar to that of the wet process but
slightly lower than that of the rubberized PEM with the terminal blend
binder and SBS modified PEM. Second, the fatigue cracking resistance
of the rubberized PEM in the dry process was similar to that of the wet
process but significantly lower than those of the rubberized PEM with
the terminal blend binder and SBS modified PEM. Third, the use of
smaller size CRM and transpolyoctenamer (TOR) in the dry process
may have made the properties of the dry process PEM close to those
of the wet process. However, the 10% CRM or 4.5% TOR used in the
study could not make rubberized PEMs produce longer fatigue life like
the control SBS modified PEM. Fourth, the introduction of SBS into
rubberized PEM by the terminal blend method may have significantly
improved the fatigue performance of PEM.