| Wax in the asphalt poses serious problems on pavement performance such as formingruts in summer and cracks in winter. Therefore study on wax-reducing technology is of greatsignificance. In the thesis, vacuum residue LYVR with high wax content was taken as thefeedstock and thermal treatment wax-reducing method was adopted. On the basis oftheoretical study of asphaltene, asphaltene dispersion stabilizer and hydrogen donor wereselected， vacuum residue LYVR as the feedstock was thermally treated in order to examinechanges in wax content with or without additives was investigated.The material LYVR in thermal treatment process, it indicated that operation in hightemperature short time(HTST) is much better than low temperature long time(LTLT) in waxreducing. When LHVR was thermally treated alone, the minimum wax-content was3.3w%and the wax-content was reduced by19.5%. When LYVR was thermally treated withadditives, for at a normal or high temperature, the selected asphaltene dispersion stabilizer canreduce the association of asphaltene molecules so that phase separation during thermaltreatment caused by physical congregation of asphaltene molecues got decreased; FCC decantoil as a hydrogen donor can release active H to suppress condensed reactions，increase thecracking severity，the minimum wax-content was2.2w%and the wax-content was reduced by46.3%. As to GDVR with wax content above3.0w%, the wax content can be reduced to2.8w%.ADSA surfactant is good effect in asphaltene stability, and as a additive, the order ofslurry oil and its fraction Hydrogen donor ability is F3﹥F2﹥F﹥F1﹥F4, light fraction F2isselected as a hydrogen donor in thermal treatment process. In residual oil thermal treatmentsystem, ADSA additive can weaken phase separation cause by asphaltene molecules physicscoacervation.Reactive hydrogen is provided by light fraction F2can restrain condensationreaction,The above two aspects in reducing coking interact with others.On the basis of studying Wax-Reducing technology, according to the principle of materialdiversify and operating process simple and feasible, we broaden and adjust the Wax-Reducingmaterial, process flow and parameters, laboratory research was finished and accomplishindustrial applications. SBS modification of base asphalt, their dosage and compatibility were also examined inthe paper，The effects of the SBS modifier and stabilizer quantity on the properties ofmodified asphalt were analyzed. The optimal dosage of SBS modifier was4.0-5.0%and thatof stabilizer was0.15-0.25%. A comprehensive evaluation of performance and compositionwas made in this thesis. It was found out the addition of SBS modifier caused theredistribution of the group fractions, and the stabilizer improved its compatibility of SBSmodified asphalt. For saving resource, on the basis of SBS modified asphalt theory, study onwaste rubber powders as modified asphalt, we finish laboratory research and study onperformance of products and mixture, at last,we accomplish industrial applications.The ageing of pavement asphalt indicated that as the ageing time was prolonged and thetemperature increased, its saturates almost kept constant, aromatics and resins obviouslydecreased, whereas asphaltenes increased. In the ageing process, with the penetration numberdecreasing exponentially and the softening point increasing linearly, the ductility was reducedand the colloid instable index was raised gradually；the structure and feature of base asphaltand asphalt before and after ageing was characterized by1H-NMR and XPS，the structuralparameter change in the ageing process showed that the composition and structure of pavingasphalt had great influence on its ageing performance. The structural uncontinuity led to thepoorer performance of ageing performance. Meanwhile, the condensation reactions occurred.Functional groups such as carbonyl and sulphoxide were formed during the aging process. Itwas shown that the ageing of pavement asphalt followed the first order reaction, followed onfree radical reaction mechanism. |
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