Research On Quantitative Analysis Of Asphalt VOCs And Inhibitor Contribution Of Zeolites

Asphalt are the most important pavement materials in the field of road engineering.However,the processing of pavement,maintenance,regeneration and service is accompanied by the generation of volatile organic compounds(VOCs).It has different degrees of harm to the physical health and environmental safety of construction personnel.General standard in research method for the analysis of asphalt VOCs is unavailable due to the complex and variable structures of it components.Based on research status of asphalt VOCs,this study focuses on the composition characteristics of asphalt VOCs.Systematic research was conducted on the characteristics of all components.The volatility laws and molecular reaction mechanisms of asphalt VOCs is investigated.Database of Asphalt VOCs Fingerprint Components and its standard curve of mass-spectrum peak area are established for quantitative analysis of single-release VOCs and the total release.At the same time,a study is conducted on the inhibition effect of zeolites on asphalt VOCs based on the full-component quantitative analysis of asphalt VOCs.The specific conclusions of this study can be summarized as follow.1.The composition characteristics of asphalt VOCs and their differences among different sources of asphalt are clarified:a closed system pyrolysis gas chromatography-mass spectrometry(PY-GC-MS)and a thermal desorption gas chromatography-mass spectrometer(TD-GC-MS)are used for synchronous comparison the asphalt VOCs.It is found that the release characteristics of asphalt VOCs are linearly and positively correlated with the sample depth.The repeatability of same VOCs relsased by same kind of asphalt material can reach about 90%.TD-GC-MS research shows that during the construction of hot-mixed asphalt,asphalt can release more than 70-100 kinds of VOCs,mainly including alkanes,olefins,hydrocarbon derivatives,cyclic substances and sulfur-containing substances.2.The reliable asphalt VOCs fingerprint component information database are established.Based on 75 asphalt VOCs component data of 16 other researchers and the full data of 5 asphalt VOCs components in this study,the Asphalt VOCs Fingerprint Components Library is established with reference to three criteria:large chromatographic peak area,high mass spectrum matching and strong pharmacological toxicity.It contains 12 components,with acetone,carbon disulfide,2-methylpentane,n-hexane,methacryl,n-butyraldehyde,3-methylhexane,benzene,isovaleraldehyde,heptane,2-methylheptane and toluene and 12 standard curves of mass-spectrum peak area for GC-MS analysis.It can achieve the quantitative analysis of any component and the total release of VOCs based on Asphalt VOCs Fingerprint Components Library.The more fingerprint component types appear in the analyzed asphalt,the higher the calculation accuracy.3.The effect of zeolite material on inhibiting the release of asphalt VOCs is analyzed.The total release of asphalt VOCs shows a binomial growth trend with increasing heating temperature.The amount of VOCs released by asphalt at 160~oC is about 2.40-4.40?g/g.Seven different characteristics of ZSM-5 zeolites were used to study the reduction effect of asphalt VOCs.The study found that 7 types of zeolites can effectively reduce 3-10 types of asphalt VOCs,but only three types of zeolites have an inhibitory effect on the total volatility,with the inhibition percentages are 42.9%,16.0%and 11.1%,respectively.The nano-polycrystalline zeolite with high granularity and high Si/Al has high inhibition effect.This study provides an important basic theory for the reduction of asphalt VOCs.In particular,the Asphalt VOCs Fingerprint Components Library was established in this study to analyze the release of major components and total release involved in asphalt VOCs quantitatively.At the same time,zeolites are used to analyze the inhibition of asphalt VOCs,to provide support for the design of bitumen VOCs highly inhibited zeolites.