Sustainable Transportation Center
Harvey, John T. (2009) Environmental Impacts and Energy Efficiency of Rubberized Warm Mix Asphalt (R-WMA) for Sustainable Road Construction: Final Progress Report . Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-09-60
Emissions from the production and paving of hot-mix asphalt are being increasingly scrutinized. The introduction of a range of warm-mix asphalt (WMA) technologies could potentially lead to a reduction in these emissions. However, the measurement of these emissions is both complex and expensive. To overcome this, a simplified protocol was developed as part of this investigation that can be used in addition to conventional methods, and which allows direct comparison of emissions from different mixes measured at the pavement surface during construction. A portable “flux” chamber is used to capture and directly measure emissions before and immediately after compaction and then two hours after compaction. Emissions are collected in activated charcoal sorbent tubes and analyzed using gas chromatography mass spectrometry (GC/MS) in the laboratory to identify individual compounds. The protocol was evaluated during the construction of a test track, which was later used in an accelerated pavement test to compare the performance of three rubberized hot-mix asphalt (R HMA) controls against seven different rubberized warm-mix asphalt (R-WMA) sections. The measured reactive organic gases (ROGs) included selected volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs). The results demonstrated that the warm mix asphalt technology type, temperature and level of compaction influence the emission characteristics significantly.