Evaluation method of storage stability of SBS modified bitumen based on dynamic rheological properties

Abstract

In order to better evaluate the storage stability of Styrene-Butadiene-Styrene Block copolymer (SBS) modified bitumen at high temperature, this paper analyzed the law of Dynamic shear rheological (DSR) test results of SBS modified bitumen after high-temperature storage and proposed DSR segregation parameters and DSR segregation index of SBS modified bitumen based on DSR test. Many kinds of SBS modified bitumen were prepared, and the application of DSR segregation index to evaluate the high-temperature storage stability of SBS modified bitumen was carried out. The main conclusions are: Take the DSR test results of SBS modified bitumen stored at high temperature but continuously stirred without segregation as the reference value, under the same storage temperature and time, the percentage of the difference of Complex modulus (G*) or Phase angle (δ) or Rutting factor (G*/sin δ) between the upper 1/3 and the bottom 1/3 of SBS modified bitumen to the reference value shows a linear relationship at different scanning temperatures. The closer the slope of DSR segregation parameters with temperature is to 0, the better the storage stability of the bitumen is. DSR segregation index takes DSR segregation parameter as parameters and is associated with the difference of segregation softening point. When the DSR segregation index is greater than 0, the storage stability of SBS modified bitumen can meet the requirements of the current standard. DSR segregation index is not bound to the type of bitumen, it is speculated that it is closely related to the compatibility between bitumen and SBS modifier. All factors affecting the storage stability of SBS modified bitumen affect the DSR segregation index. DSR segregation index has high stability in the evaluation of high-temperature storage stability of SBS modified bitumen and can be used as an auxiliary evaluation index of 48 h segregation softening point difference.