Fracture resistance and thermo-mechanical performance of asphalt mixes with crushed waste glass fine aggregates

This study investigates the fracture resistance and thermo-mechanical performance of dense graded hot mix asphalt (HMA) incorporating Crushed Waste Glass (CWG) fine aggregates, replacing Crushed Rock (CR) at 0%, 2.5%, 10% and 42.5% by total mix weight; using standard testing methods and novel experimental techniques. The Marshall tests provided insights into mixture volumetrics, while load-displacement curves highlighted stiffness variations across mix designs. Fracture resistance was studied using the Indirect tensile Asphalt Cracking Test (IDEAL-CT) test on 150 and 101.6 mm samples. The CTindex and fracture parameters depended on CWG content and sample size. The thermo-mechanical behaviour and crack propagation characteristics of mixes were further analysed using the Brazilian indirect tensile splitting test at −20°C, 0°C and 60°C, integrated with stereo high-speed photography. Results revealed tensile and shear crack formations with ultimate tensile strength, peak stiffness, crack initiation loads, and crack speeds influenced by test temperatures and mix designs. Thermal parameters-specific heat, thermal conductivity, and diffusivity were measured using the Transient Plane Source (TPS) method, offering additional information on the fracture response. Finally, the Hamburg Wheel Tracking tests demonstrated improved rutting and moisture resistance in mixes with 10% CWG, with the lowest rut depth and highest Stripping Inflection Point (SIP).