Experimental and numerical performance evaluation of hot mix asphalt with waste natural pozzolanic fillers

Mineral fillers affect mastic properties and high-temperature performance of hot mix asphalts (HMA). This study investigated three waste natural pozzolans as mineral fillers and their effects on Marshall response, mixture stiffness, moisture susceptibility, and static creep behaviour. HMAs were evaluated using Marshall stability and flow, moisture susceptibility, indirect tensile stiffness modulus (ITSM), and static creep tests. Creep behaviour was modelled using the finite element method with a time-hardening power law, calibrated against experimental static creep responses. Performance varied with filler type and substitution level. Marshall stability and stiffness generally increased with waste pozzolan, and the highest performance was obtained with 100% green pozzolan. Marshall stability increased by approximately 24% and ultimate creep stiffness by approximately 23% compared with the pure mixture. All mixtures met the 80% tensile strength ratio (TSR) specification limit, indicating no negative impact on moisture susceptibility. The green pozzolan’s performance may be associated with its higher CaO content, although filler physical and surface characteristics were not assessed. The calibrated finite element model closely reproduced experimental creep curves and ultimate stiffness at 150 kPa and explored responses at additional stress levels. Waste pozzolans are therefore technically viable fillers, although environmental and economic sustainability were not quantitatively assessed..