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Investigating the field short-term aging of high content polymer-modified asphalt

ABSTRACT High Content Polymer-Modified Asphalt (HCPMA) is gaining popularities due to its superior performance. However, high production temperatures are required during the HCPMA pavement construction, which could easily lead to serious short-term aging. This study aims to study the impact of field short-term aging on HCPMA’s chemical and rheological properties. HCPMA binders used in three field projects were recovered and examined using Gel Permeation Chromatography (GPC), Fourier Transform Infrared (FTIR) and Dynamic shear rheology (DSR). Additionally, to compare between the laboratory aging and field aging, binders recovered from the laboratory Short-term Oven Aging (STOA) as well as binders aged by Rolling Thin Film Oven Aging Test (RTFOT) were examined. The result suggests the aging effects of the standard RTFOT are too weak to simulate the field aging of HCPMA and the actual field aging level lies between RTFOT and STOA. It is also found the aging of HCPMA contains the hardening of asphalt and the degradation of SBS polymer, and the process of polymer degradation exerts more influence on the HCPMA binder’s viscoelastic response (i.e. phase angle) rather than its stiffness (i.e. modulus). After field short-term aging, HCPMA binder becomes stiffer and less elastic.