Characterization of long term field aging of polymer modified bitumen in porous asphalt

The effect of long term field aging on different types of polymer modified binders used in two-layer porous asphalt is studied using different test methods. Chemical and rheological tests are performed on samples taken from road sections at different moments in time in search of trends in long term field aging. The results show that chemical analyses performed with GPC and infrared can be used to study the effect of short term aging. However, these tests are not accurate enough to establish the more subtle trends that play a role in long term field aging. The tests proved to be very valuable to determine the type of modification in the binder. Master curves showing the complex modulus and the phase angle at different temperatures determined with the Dynamic Shear Rheometer (DSR) show linear trends for long term aging when an aging period of 8 years is observed. As expected the complex modulus increases with aging, while the phase angle decreases. There is one exception to this, in polymer modified binders the phase angle decrease with age at low loading frequencies which can be related to degradation of the polymer modification. Long term field aging, polymer modified binder, GPC, FTIR, DSR. © RILEM 2012