Airborne Emissions Assessment of Hot Asphalt Mixing Methods and Limitations

Abstract

Hot mix asphalt industries are required to meet airborne emissions thresholds, yet only a few types of emission measurements are available. This study is therefore aimed at evaluating the influence of operating parameters on airborne emissions at the plant stack, especially Gaseous Organic Compounds (GOC), in addition to identifying both the best mixing conditions and bitumen influence through laboratory testing. Emission measurements have been performed for a given set of production conditions, and results highlight significant changes in emission flows. CO2, SO2, NOx, and GOC all seem to be correlated with combustion intensity and energy consumption, whereas CO tends instead to be associated with combustion efficiency. Laboratory GOC variations exhibit monotonic increases with temperature; at the plant level, these effects are concealed by combustion scattering due to burner adjustment. Flow assessment is provided at the plant for each pollutant along with its dispersion.