Chemical, morphological and rheological investigations of SBR/SBS modified asphalt emulsions with waterborne acrylate and polyurethane

The performance of asphalt emulsion tended to be unsatisfactory for pavement maintenance or cold mix paving due to deficiency of cohesive strength, even if SBR/SBS modification had been conducted. Compared to the traditional modified asphalt emulsion, the application of waterborne modifier showed greater advantages on convenience and flexibility. In this research, the feasibility of waterborne acrylate and polyurethane, as novel potential modifiers, to further enhance performances of SBR/SBS modified asphalt emulsion was investigated. The compatibility between modifier and emulsified asphalt was studied firstly and the chemical changes during the modification process were characterized by Fourier transform infrared (FTIR). The dynamic shear rheometer (DSR) tests were carried out to comprehensively evaluate the high-temperature rheological properties, including performance grade (PG) determination, frequency sweep and multi-stress creep recovery (MSCR) tests. Then fluorescence microscope was applied to observe the distribution of modifier in the residue. Finally, the statistical analysis was conducted based on gray relational analysis (GRA). The results revealed that waterborne cationic acrylate presented the best effectiveness of modification for SBS modified asphalt emulsion with considering storage stability and improved high-temperature properties, potentially providing a more effective and modified method to prepare cold binder with high performances. (C) 2020 Elsevier Ltd. All rights reserved.