Rheological, Mechanical, and Chemical Characterization of Asphalt Binders and Mixtures with Waste Tire and Plastic Pyrolytic Chars

Abstract

Pyrolysis technology is receiving growing attention for managing postconsumer tire and plastic waste streams. Pyrolytic char is generated as a byproduct in the pyrolysis process and faces challenges regarding its stable and reliable reuse. The use of tire pyrolytic char (TPC) and plastic pyrolytic char (PPC) has recently gained interest in asphalt binder modification, which can be a feasible and attractive alternative for their utilization. The present study focused on a multifaceted investigation at three levels: (1) characterization of the pyrolytic chars (TPC and PPC), (2) characterization of asphalt binders modified with different dosages (0%, 5%, 10%, 15%, and 20%) of TPC and PPC focusing on conventional, rheological, microscopic, and thermochemical tests, and (3) mechanical characterization of asphalt mixtures fabricated with TPC- and PPC-modified binders in terms of rutting, moisture damage, and fatigue performance. Leachate toxicity was also evaluated to ensure that the use of TPC and PPC in asphalt mixtures is safe for the environment. Results showed that both TPC- and PPC-modified binders and mixtures showed better rutting resistance than the control binder and mixture up to 20% dosage. Fourier transform infrared (FTIR) spectroscopy showed that TPC and PPC interacted chemically with the base binder during modification. Leaching tests indicated that TPC and PPC could be safely used in asphalt mixtures for pavement construction. Comparing the fatigue and moisture damage results, it was found that the optimum performance was achieved at a 10% dosage of both TPC and PPC. This observation was consistent with fatigue tests on binders and asphalt mixtures.