The Effect of Baghouse Fines and Incomplete Combustion Products in a Drum Drier on the Characteristics of Asphalt Paving Mixtures - Phase I

The major purpose of this study was to use the high pressure-gel permeation techniques to evaluate the changes in asphalt subjected to different mix production parameters, including plant type, level of aging and fuel used in the burner of the drier. Additional objectives were to establish correlations between physical parameters of asphalts and their chromatographic parameters, and to determine whether the HPGPC technique could be used to detect burner fuel contamination in the mix produced by asphalt plants. This study determined that the HPGPC technique is an excellent comparative analysis tool, capable of detecting changes in the aging of asphalt, but not repeatably capable of establishing direct relationships between chromatograms and physical parameters. Results of the study also show that no significant differences could be found by HPGPC between mixes produced by drum plants and batch plants, or by plants using different burner fuels. HPGPC can also detect fuel contamination at the 1% contamination level, not detectable by physical measures. Finally, results of this study show that the 5 hour thin film oven test does not simulate aging produced by asphalt plants, and should be reevaluated