Maxwell Model Analysis of Bitumen Rheological Data
Date of Original Version
Maxwell models have been parameterized on the basis of rheological data from the literature for bitumens used in pavements to relate differences in rheology to underlying differences in mechanical relaxation times. The data employed were previously measured for bitumens without aging, with rolling thin-film oven (RTFO) aging, and with subsequent pressure aging vessel (PAV) aging. Bitumens in different data sets included different types of bitumen modification. Full time-temperature superposition was applied, with horizontal shift factors aT based on achieving superposition of phase angle tangent (tanδ) and vertical shift factors bT determined based on overlap of storage and loss moduli. The results determined for the horizontal shift factor followed the Williams-Landel-Ferry equation with parameters that differed for each bitumen. Dynamic modulus data were represented by using a series of discrete Maxwell models. Fand suggested a continuous yet asymmetric distribution of relaxation times on a logarithmic time axis. PAV-aged bitumens showed increased modulus contributions at longer relaxation times than RTFO-aged bitumens. © 2011 American Society of Civil Engineers.
Journal of Materials in Civil Engineering
Badami, Joseph V., and Michael L. Greenfield. "Maxwell Model Analysis of Bitumen Rheological Data." Journal of Materials in Civil Engineering 23, 10 (2011): 1387-1395. doi:10.1061/(ASCE)MT.1943-5533.0000318.