This study focuses on the green maintenance technology using 60% RAP plant-mix hot recycling, aiming to reveal the emission characteristics of asphalt mixtures with different gradations in road green maintenance and support low-carbon transportation infrastructure. Three asphalt mixtures, GAC-13, SMA-13 and GAC-20, were tested. Emissions of VOCs, inorganic gases and particulate matter during production and construction were monitored. Summa canisters with GC-MS, flue gas analyzers and filter membrane gravimetric methods were adopted for pollutant measurement. Results show that under 60% RAP hot recycling, SMA-13 emits more alkanes and amines than GAC-13 and GAC-20 at both construction sites and mixing plants. For CO₂ and particulate matter, emissions at construction sites and mixing plants both follow the order SMA-13 > GAC-13 > GAC-20. These findings clarify the gaseous emission differences among gradations and provide data support for low-carbon road maintenance technology selection and emission control.
Liu et al. (Tue,) studied this question.