Comprehensive performance evaluation of high polymer-modified asphalt binders beyond linear viscoelastic rheological surrogates

Abstract

• High polymer-modified (HP) binders exhibit superior performance compared to PMA. • LVE surrogates fail to predict failure properties of complex and modified binders. • HP binders displayed higher strain tolerance in DENT compared to conventional PMA. • HP binders tend to have lower cracking temperature in ABCD compared to typical PMA. • FTIR I PTDB and I PVDB indices can be used to detect potential polymer degradation. Polymer modification of asphalt binders has progressively become more common over recent decades. Styrene-Butadiene-Styrene (SBS) is a well-recognized elastomer that has been commonly used in asphalt pavements. SBS polymer specifically exhibits a chemical morphology of hard polystyrene segment tethered by soft polybutadiene segment. Concerns related to binder pump clogging and reduced mixture workability have limited the SBS copolymer content in polymer-modified asphalt (PMA) to around 3 %. This motivated researchers to develop a new SBS polymer structure by modifying the midblock structure to have much higher vinyl content. High polymer-modified (HP) binder technology allowed the use of SBS at higher levels of 7–8 %. Although several studies have highlighted the positive impacts of HP on asphalt binders, they were mostly limited to the linear viscoelastic (LVE) domain. Therefore, there is still a need for a comprehensive evaluation of HP binders that considers failure properties, which constituted the main motivation of this research. In this study, Multiple Stress Creep Recovery (MSCR), Double Edge Notched Tension (DENT) and Asphalt Binder Cracking Device (ABCD) test results showed that HP binders exhibited superior performance compared to PMA in terms of higher strain recovery and lower non-recoverable creep compliance at high temperatures (52–70 °C), higher strain tolerance at intermediate temperature (25 °C), and lower (colder) cracking temperatures at sub-zero temperatures. Additionally, chemical analysis showed minimal HP degradation potential compared to PMA.