Composite Asphalt Binder Formulation Utilizing Residual EPDM Rubber and Waste Plastic Pyrolysis Oil

Abstract

The exploration of alternative energy sources has broadened to include modifying or partially replacing asphalt binders with materials derived from waste for use in road construction. This study optimized the formulation for preparing composite or hybrid asphalt binders by combining waste plastic pyrolysis oil (WPPO), produced during the pyrolysis of waste plastics, with waste ethylene propylene diene monomer (EPDM) rubber granules from nontire automotive rubber components. The study was executed in three phases: (1) the use of grey relational analysis (GRA) to optimize parameters for formulating composite rubberized asphalt binders using three distinct approaches—sequential addition, heat pretreatment, and microwave pretreatment; (2) application of the response surface methodology (RSM) to optimize blending parameters for formulating composite rubberized asphalt binders, encompassing shear rates, blending and curing temperatures, blending time, and curing time; and (3) evaluation of the viscoelastic rheological performance and microstructural features of differently modified asphalt binders under optimized conditions. The heat-pretreated composite asphalt binder, with WPPO-EPDM rubber composite, subjected to optimized heat-pretreatment conditions (90°C for 2 h) and formulated with optimal blending parameters (shear rate of 5,000 rpm, blending and curing temperatures of 160°C, blending time of 1 h, and curing time of 2 h), exhibited significant and synergistic improvements across a broad temperature and performance range. The study’s findings highlight the potential of using waste plastic pyrolysis oil and EPDM rubber granules from nontire automotive rubber components to enhance the performance of asphalt binders through composite modification.