Effects of asphalt source and mixing temperature on the generated asphalt fumes.

Asphalt fumes generated in pavement construction have been extensively studied from the perspective of occupational health. In this paper, they are examined from the perspective of material and construction. Asphalt binders from different sources were used to create standard mixtures. An asphalt fume generation and collection system was designed and built for generating fumes at simulated construction conditions and collecting fumes similar to the procedure used in field exposure studies. Total particulates (TP) in the fume samples were analyzed gravimetrically, and the chemical components of the samples were identified by using GC/MS. Results indicate that the TP concentration and chemical component of asphalt fumes are dependent on asphalt source and temperature. The concentration from one asphalt can be several times higher than that from another. With a temperature rise in 20 °C, the concentration increases about 3-7 times. At 140 °C, the total number of detected PAHs ranges from 4 to 9; at 160 °C, the number ranges from 4 to 12. The hazardous potentials of asphalt fumes vary with asphalt source and mixing temperature. Therefore, standardized laboratory test procedures are needed for risk assessment, based on which proper material selection and construction strategies may be chosen for hazard mitigation.