Research Methodologies On The VOC Emissions From Bituminous Materials And Its Inhibitor

The expressway mileage in China has already exceed 111.95 thousand kilometer by the year 2014,ranking NO.1 all over the world, of which asphalt pavement accounts for more than 90%. In addition, the road asphalt consumes over 15 million annually. As the main raw material of road construction, asphalt is composed of different hydrocarbon and its derivatives, which has complicated species and different chemical stability, acting as anticorrosion, water-proof and adhesion. However, volatile organic compounds(VOC) volatilize in quantity during production and application of asphalt, especially the pavement with high temperature. VOC coagulates in the air as gas, aerosol and particulate matter, resulting in serious pollution. There are abundant research manifesting that benzopyrene, anthracene naphthalene, acridines, pyridines and phenols in over 100 kinds of components of asphalt would create great damage to human health.Actually, there aren't that many researches on asphalt VOC particularly on the components of VOC, in that qualitative and quantitative analyses are quite difficult for VOC's small quantity, various species and dynamic activity. One of the difficulties in research is that complicated components and lean density of VOC require more accurate and extensive apparatus. The other is that the open fields on which asphalt is paved change a lot, which adds to the difficulty for gathering VOC. Therefore, it's crucial to seek out rational qualitative-quantitative analysis methods and VOC analysis instruments which can simulate construction site in the lab, in order to decrease VOC's emission and develop effective asphalt VOC inhibitor.Considering the difficult research on analysis and suppression of asphalt VOC, firstly, the paper establishes three kinds of apparatus to collect asphalt VOC in lab. One is used to collect VOC that volatilizes after being heated with certain temperature. Another is designed to gather VOC when asphalt correct is agitated. And the third one is to collect VOC when asphalt correct is put to use and from high temperature to cooling. After asphalt VOC being gathered, the factor and law for asphalt VOC emission in the condition of the laboratory environment can be seek out with the methods of gravimetric and ultraviolet and visible spectrophotometry(UV-VIS), providing theoretical foundation and reference data to develop environmental asphalt. Secondly, this paper provides a innovative way in asphalt VOC qualitative and quantitative analyses. The paper applies some modern analytical techniques such as TG-MS coupling technique to analyze components of asphalt VOC and the content of specific constituent. The result not only reflects the inhibitor's effect on asphalt VOC, but also proves that TG-MS coupling technique is qualified to make qualitative and quantitative analyses on asphalt VOC, estimate effects of different inhibitors and supply simple but valid criterion to develop inhibitor.Thirdly, the paper refers to three kinds of monomer inhibitors and two composite inhibitors. Selecting LDHs, SBS and activated carbon and utilizing the testing methods and VOC's gathering-analysis apparatus mentioned above, this paper successfully testifies that SBS and activated carbon restrain asphalt VOC's emission obviously but have little influence on asphalt functional types. On the basis of confirming the best dosage of monomer inhibitors, this paper discovers two composite inhibitors, that is 4% SBS together with 4% activated carbon and 5% SBS together with 4% activated carbon, and certifies composite inhibitors own better effects both on asphalt itself and agitation & pavement. Moreover, inspected by the PM micro particles tester, the amount of modified asphalt correct releases substantially less after composite inhibitors added into asphalt.Lastly, the paper discusses the influence of composite inhibitors on asphalt and asphalt correct performance. The experiment proves that composite inhibitors make positive effects on asphalt regular performance, rheological property and ageing resistance, nevertheless, it has little effect on the four components of asphalt. The water damage resistance and high-temperature stability are both improved owing to the addition of composite inhibitors, which illustrates composite inhibitors are beneficial to asphalt pavement performance as well.