Cross blend mechanism of SBS modified asphalt based on infrared spectra

High-speed shearing technique was utilized to provide the SBS physical and chemical modified asphalt in the laboratory. Based on the infrared spectra, the heterocyclic compound and the diagnostic functional group of the asphalt are analyzed and the cross blend mechanism of SBS modified asphalt is revealed by comparing the spectrogram of matrix asphalt, SBS, SBS physical and chemical modified asphalt. It was found that the spectrogram of SBS physical modified asphalt is the simple superposition of the SBS spectrogram and asphalt spectrogram. There is only physical mixing without any chemical reaction between SBS and matrix asphalt. However, the spectrogram of SBS chemical modified asphalt does not just show that the chemical reaction occurs between SBS and matrix asphalt due to the appearance of macromolecule free radical in the SBS under the action of shearing force and stabilizer. It also can be caused by the graft reaction between SBS and matrix asphalt after the joint reaction by SBS itself. The content of SBS in SBS modified asphalt can be determined by infared spectra to evaluate the pavement performance of SBS modified asphalt.