Study on the effect of USP modifier on the high temperature rheological properties of SBS-modified asphalt

In recent years, domestically produced USP low-temperature modifiers have attracted attention because of their simple raw materials, low prices and good viscosity reduction effects. However, viscosity reduction may also impair high temperature performance. This study examined the effects of USP-C1 type modifier at 2%, 4%, 6%, and 8% dosage on the conventional and high temperature rheological properties of SBS-modified asphalt. From the results of the three index tests and Brinell rotational viscosity test, it can be seen that the USP modifier can considerably lower the viscosity of SBS modified asphalt and enhance its low temperature performance; from the results of the dynamic temperature scanning test, it can be seen that the USP modifier reduces the complex modulus and the rutting factor of SBS modified asphalt, which adversely affects its high temperature performance; from the results of the Multiple Stress Creep Recovery (MSCR) test, it is evident that the the addition of USP increased the cumulative strain response and irrecoverable creep flexibility of SBS modified asphalt. The research in this paper provides theoretical support for the application of USP modifiers in road engineering.