Characterization and Performance Evaluation of Polymer-Modified Flexible Pavement Incorporating Waste Plastics

This study investigates the characterization and performance of polymer-modified flexible pavement mixes incorporating waste plastic and crumb rubber. VG-30 bitumen was modified using two approaches: (i) a dry-mix plastic coating process and (ii) crumb rubber addition to produce CRMB. A control mix and six modified mixes—P5, P10, R10, R15, P5+R10, and P10+R15 (numbers indicating percentage by weight of bitumen)—were designed using the Marshall method. Performance evaluation included Marshall Stability and Flow, Indirect Tensile Strength (ITS), Moisture Susceptibility (TSR), Wheel-Tracking Rutting, and Fatigue Life. Results showed that all modified mixes performed better than the control. After converting stability values from kgf to kN, stability increased from 11.60 kN (Control) to 14.91 kN (P10+R15), while maintaining acceptable flow values (2.9–3.8 mm). ITS improved from 0.95 MPa to 1.82 MPa, and TSR values exceeded the 80% durability threshold, reaching a maximum of 87% for P10+R15. Rutting depth decreased from 4.8 mm to 2.5 mm, and fatigue life increased significantly from 14,000 to 23,000 cycles. The combined modification enhanced stiffness through plastic and elasticity through rubber, resulting in superior overall performance and promoting effective solid-waste utilization. The mix P10+R15 is recommended for heavy-traffic corridors in warm and wet regions, subject to field validation and compliance with IS/IRC/AASHTO specifications. Environmental benefits include reduced waste disposal and lower binder consumption.