Study On Performance And Suppression Effect Of Inhibitors Modified Asphalts

Asphalt can produce a large number of toxic and hazardous asphalt fumes at theprocessing of mixing and paving and in the service process, which are not onlyharmful for the constructors, but also bring different levels of pollution to naturalenvironment, such as atmosphere, soil and water. There has the vital significance onthe health and ecological environment to explore how to reduce asphalt fumes. On thebasis of consulting a large number of literatures and sacrificing the performances ofasphalt, asphalt additives were investigated in this paper to reduce the emission ofasphalt fumes to achieve the best control of asphalt fumes emission.First, this paper investigated the influences of these inhibitors on physical andrheological properties of the bitumen. Results show that the penetration and ductilityof inhibitor bitumen are decreased, whereas the softening point and are increased withthe addition of inhibitors. The complex shear modulus reduces slightly while thephase angle increases when the inhibitors are added. The inhibitors can improve theability of bitumen to resist cracking. TLC-FID analysis shows that the content ofaromatics and saturates changes slightly when the inhibitors are added. The content ofresins decreases, whereas the content of asphaltenes increases with the addition ofinhibitors. FT-IR test tells that there is little change in peak position and peak areawith the addition of inhibitors.Second, based on the laboratory conditions of asphalt fumes emission,conducting the researches of the laws and examining the inhibitory effect of threekinds of inhibitors on the asphalt, the best inhibitor and its content were got. Theresults showed that the asphalt fumes were mainly composed by the particles whichdiameter are large than1μm, but the particles which diameter are less than1μm andthe gaseous substances were very small, the factors of affecting asphalt fumescontains asphalt types, heating time, heating temperature, etc. When heatingtemperature is up to180℃, the emission of asphalt fume increased quickly. Theemission of asphalt fume increases with the increasing of heating time. For the threeasphalt additives used in this paper, SBS and activated carbon have better effects onfumes suppression, while the suppressive effect of layered double hydroxides (LDHs)is relatively poor. The optimal amount of LDHs, SBS and activated carbon for achieving the best control of fumes emission is4wt%,4wt%and5wt%, respectively,when the adding level of activated carbon is5wt%, the reducing rate of the asphaltcan reach33.5%.Finally, Thermogravimetry–mass spectrometry (TG–MS) was used to analysissome compositions of the asphalt fume. TG data show that the rate loss of asphaltreduced with inhibitor increases. DSC shows that asphalt heat quantity was decreasedby comparing with the fresh asphalt, so the compositions may change in theexperiment temperature range decrease. With mass spectrometry, the thesis detectedthe production of asphalt volatilization and thermal decomposition course, whichcontain the mass-to-charge ratio below90, polycyclic aromatic hydrocarbons (PAHs)and other organic compounds. Results show that SBS and activated carbon havebetter effects on asphalt fume while the suppressive effect of layered doublehydroxides (LDHs) is relatively poor. With respect to restrain asphalt fumes emission,the optimal amount of LDHs and activated carbon is4wt%and5wt%. However, it isdifficult to decide the best control ratio for SBS because of SBS inhibitor has choicefor the effect of suppression to compounds.