Mechanical investigation and environmental life cycle assessment of warm mix asphalts

The road sector is continuously seeking for more sustainable solutions to build and maintain asphalt pavements with lower energy and non-renewable resources consumption; the Warm Mix Asphalt (WMA) potentially matches these targets combining lower mixing/laying temperatures and high RAP content. The study develops an investigation workflow for the simultaneous assessment of the mechanical and environmental features of 9 WMAs characterized by different RAP contents (30/40/50%) and mixing/laying temperatures (110/120/140°C). The methodology involves the determination of air voids, compaction energy, stiffness modulus, moisture sensitivity, fatigue resistance and Life Cycle Assessment applied to 1 m2 of asphalt pavement for a 20 y analysis period. The results show that accompanying the mix design phase with an assessment of the CO2 equivalent emissions of the life cycle of the pavement allows to achieve the best mechanical-environmental synergy, leading to a reduction of 45 kg CO2eq/m2 in 20 years compared to the baseline WMA.