Arrhenius model-based analysis of high-temperature properties and temperature sensitivity of SBS/CR modified asphalt

The response of modified asphalt binders to temperature exhibits considerable variability depending on the binder type and composition. This variability can lead to biases in evaluating high-temperature performance. This study comprehensively evaluates the high-temperature rheological properties and thermal stability of SBS-modified and crumb rubber (CR)-modified bitumen, utilizing Dynamic Shear Rheometer, FM, FTIR, TGA-DSC tests. The findings indicate that mechanical properties—including dynamic shear modulus, rutting factor, non-recoverable creep compliance, and zero shear viscosity—adhere to Arrhenius behavior as a function of temperature, yet phase angle presents non-Arrhenius characteristics. The thermal dependence of mechanical properties is quantified by the Arrhenius model parameter activation energy (E_a), with E_a values varying by binder type, polymer content, and test method. Specifically, the rutting factor exhibits weak temperature dependence for all binders, likely due to test conditions of linear elasticity and small strain. Furthermore, the E_a parameter of viscoelastic properties of SBS and CR binders shows a nonlinear frequency dependence within the experimental frequency range (0.01 Hz to 10 Hz). Increasing polymer concentration, the response of E_a to frequency changes accelerated. TGA-DSC testing revealed that CR and SBS raise the initial decomposition temperature of pure asphalt by 6.1 % and 5.4 %, respectively, while the thermal decomposition of SBS accelerated mass loss in the modified asphalt. FTIR analysis showed that CR formed chemical bonds with asphalt, while SBS provided physical modification. During aging, storage modulus showed greater aging sensitivity than loss modulus, making it a better indicator of aging resistance. A refined ranking parameter $\left[\frac{E_a}{G^{*}/\sin \delta }\right]$was proposed based on rheological theory and the Arrhenius model applied across a wide temperature range. The parameter not only enhances the evaluation of the rutting factor in the SHRP system but also provides an important reference for considering temperature sensitivity in high-temperature specifications.