Physico-chemo-rheological characterization of neat and polymer-modified asphalt binders

Abstract

The physico-chemo-rheological properties of asphalt binder are critical for the long-term performance of asphalt pavement infrastructures. The objectives of this study are to characterize the physico-rheological properties of unmodified neat and polymer-modified asphalt binders with newly developed rheological performance tests, and further investigate the binder chemical properties as well as the possible performance relationship from macroscale to microscale perspective. Three neat asphalt binders and two styrene–butadiene–styrene (SBS) modified asphalt binders are selected in this study. The physical properties of asphalt binder include traditional penetration, softening point and ductility. The saturates, aromatics, resins and asphaltenes (SARA) fractionation test, gel permeation chromatography (GPC) and fourier transform infrared spectroscopy (FTIR) tests are respectively conducted to quantify the chemical composition, molecular weight distribution and structure properties of asphalt binders. The rheological rutting and fatigue resistance are evaluated through the multiple stress creep recovery (MSCR), linear amplitude sweep (LAS) and DSR-based elastic recovery (DSR-ER) tests. Experimental results indicate that the physical properties are only effective to distinguish the rheological performance of neat asphalt binders. The lower aromatics contents improve the binder rutting resistance and an unified relationship between aromatic contents and binder rutting performance is obtained for both neat and modified binders. In addition, increasing the amount of small asphalt molecules decrease the resistance to permanent deformation respectively for neat and modified binders. However, the small asphalt molecule is favorable for improving the binder fatigue performance. The large molecular size (LMS) parameter from GPC test is demonstrated a unified correlation to the fatigue life of both neat and modified binders.