Performance evaluation of asphalt binder modified with lignin-derived nanocarbon

ABSTRACT

This paper evaluates the mechanical behavior of nanocarbon modified asphalt binder. The nanocarbon was produced by a pyrolysis process of lignin. Three samples of asphalt binder were used as base for modification, a Pen 30/45, a Pen 50/70, and a SBS-polymer-modified 55/75. Different conditions of temperature, stirring speed, and modification time periods were evaluated to identify the best operational conditions. The characterization of nanocarbon was performed by different methodologies. Performance tests were conducted in a dynamic shear rheometer (DSR) to determine dynamic shear modulus, phase angle, and parameters of the Linear Amplitude Sweep test (LAS) and Multiple Stress Creep and Recovery test (MSCR) on the modified and unmodified asphalt samples. Furthermore, tests were performed in a bending beam rheometer (BBR) to measure the flexural creep stiffness and m-value at low temperatures, as well as the ∆Tc parameter. The samples were submitted to short- and long-term aging, and then master curves were constructed from frequency sweep dynamical shear tests. The results indicated that small amounts (0.02% to 0.05%, w/w) of nanocarbon adopted in the research were enough to improve rutting, fatigue, and aging resistance. Finally, the results also revealed that the modified asphalt 55/75 was better homogenized with the nanocarbon than the neat asphalt cements 30/45 and 50/70.

Keywords
Nanocarbon; aging; asphalt binder; fatigue; rutting