Improvement of thermal-oxidative stability of petroleum bitumen using “overoxidation–dilution” technology and introduction of antioxidant additives

Abstract

ABSTRACTThis article presents the results of the research that was aimed at obtaining road bitumen with increased thermal-oxidative stability. Road bitumen samples with increased thermal-oxidative stability were obtained by the method of “overoxidation–dilution” by means of selection of raw materials, oxidation process parameters, and also a plasticizer at the stage of compounding. To estimate the thermal-oxidative stability of the bitumen samples change in the value of softening point of bitumen after heating the samples for 5 hr was used. The “overoxidation–dilution” technology makes it possible to obtain a concentrate of asphaltenes or to produce a dispersed phase at the first stage, then a diluent is introduced into the system to create a dispersion medium of bitumen with required characteristics. Also, the possibility of regulation of road bitumen aging by introducing antioxidant additives from the class of sterically hindered phenols was investigated. During the research, it has been revealed that the effectiveness of antioxidants is influenced by the time of their input to a bitumen system: the lesser the bitumen stored before introducing an additive, the higher the effect of additives introduction.