LAUSR

Abstract To improve the properties of styrene-isoprene-styrene (SIS) modified asphalt and decline the SIS content in asphalt further, SIS compound modified asphalt has been prepared by the addition of SIS, polyphosphoric acid (PPA) and sulfur. The physical and rheological properties of modified asphalts were studied and the structural characteristics were analyzed by adopting morphology observation, infrared spectroscopy and thermal analysis. The research showed the suitable addition of PPA improved the high- and low-temperature properties of asphalt and declined the SIS content without negative effect. The use of sulfur can improve the storage stability of modified asphalt greatly and increase the susceptibility to ageing. The morphology and infrared analysis indicate the effects of PPA, sulfur and ageing on the structural characteristics of asphalt. The calculation for the characteristic peaks of enthalpy curves in thermal analysis was used to investigate the influence of PPA and sulfur on the distribution of molecule weight and constitutes of SIS modified (SM) asphalt before and after ageing efficiently.