Preparation And Microstructure And Properties Of Modified Oxidized Asphalt With ESO And Fibers

With the increasing of road construction and the improving of highway quality in China, the demand of the high-grade pavement asphalt is getting higher, thus the production of the asphalt is needed urgently. At present the expedient solution is mass importation. Moreover, the roads paved with general-purpose asphalt can't afford the the gradual increase of heavy traffic and suffer the over-loaded vehicles, the road construction practice has showed that the dosaging of synthetic fibers into asphalt extended the pavement service life in addition to its economical competition and convenient application.The epoxidized soyabean oil was used to modify oxidized asphalt, and the modification mechanism, the microstructure and the physical and mechanical properties as well as the thermally aging behavior of the modified were investigated in detail. Two kinds of polyester fibers were mixed into the modified asphalt and their structure-property relations were studied. The structure and properties of the AH-70 heavy transport pavement asphalt and of the modified oxidized asphalt were compared after polyacrylonitrile fiber was added. The important conclusions were made as follows:(1) The softening temperature and the penetration were decreased and the ductility was increased with the increase of epoxidized soyabean oil. The experimental results indicated that, agitation temperature majorly controlled the oxidation of asphalt, while mixing time mainly dominated the mixture uniformity. The microstructural analysis of the modified asphalt showed that, there existed a strong physical-chemical interaction between the polar epoxy group of epoxidized soyabean oil and the hydroxyl group in oxidized asphalt, which substantially improved the compatibility of the oil and the asphalt. The physical and mechanical properties of the modified asphalt more or less approximated those of high quality road asphalt.(2) The softening temperature of the modified increased and the penetration and the ductility decreased with the increase of polyester fiber. The fiber supported network structure in the modified mixtures was formed as the fiber content surpassed 3%, afterwards the physical and mechanical properties were changed slightly. After subjected to the fatigue experiment, the penetration and the ductility of the fiber-asphalt binders decreased to less extent. This implied that a stabilization effect of the fiber network structure took place.(3) The comparison experiment showed that, the fracture toughness of PAN fiber-oxidized asphalt binders was very close to that of the fiber-heavy traffic pavement asphalt when the fiber content was in the range of 1%～3%, and the fracture toughness of PAN fiber-oxidized asphalt binder was slightly better than that of the fiber-pavement asphalt when the fiber content was 1 %.(4) The surface morphology of fibers influenced their mixing and dispersion. PAN fiber with the longitudinal gullies helped to strengthen its dispersion and interfacial adhesion, whereas the oil adsorption of polyester fiber aggravated the flow ability of asphalt.The innovation point in this thesis is that, the epoxidized soyabean oil was first employed to improve the ductility and penetration of the oxidized asphalt, and fracture toughness was improved substantially.