Abstract:
Waste or end-of-life tires are generated in huge quantities all over the
world and pose a serious challenge for the environment. Pyrolysis is a quite effective
chemical route for recycling of waste tires, and produces three-phase products:
liquid pyrolytic oil, gases, and solid tire pyrolytic char (TPC). The TPC is generally
considered a by-product of waste tire pyrolysis process and has recently gained
interest as an additive/modifier to road asphalt binders. Rutting in thick asphalt layers
is a commonly observed distress on heavy-duty flexible pavements, which are quite
preferred in India as well as throughout the globe. Rutting in the asphalt-bound pavement
layers refers to the accumulation of permanent deformation under the influence
of high pavement temperatures and heavy traffic. Asphalt binders play a significant
role in imparting rutting resistance to an asphalt concrete pavement layer. Evaluation
of rutting resistance of TPC modified binders and mixtures is thus quite important
to support its wide-spread use in construction of asphalt pavements. This study first
evaluated the rutting performance of TPC modified binders (prepared at five TPC
contents) at multiple temperatures (40, 50, 60, and 70 °C) and stress levels through
five rheological parameters: (1) Superpave rutting parameter; (2) Shenoy rutting
parameter; (3) zero shear viscosity; (4) non-recoverable creep compliance (Jnr) from
multiple stress creep and recovery (MSCR) test; and (5) non-recoverable strain rate
( εnr ) from the MSCR test. A dynamic shear rheometer was used to measure the
TPC modified asphalt binder rutting characteristics. Asphalt mixtures were then
fabricated using the TPC modified binders and evaluated for rutting performance
using the Hamburg wheel-tracking device. Correlation analysis was performed for
binder rutting parameters and mixture rut depth. Overall, the findings indicate that
the addition of TPC enhances the rutting performance of both asphalt binders and
the asphalt mixtures.
