Analysis of low temperature performance and viscoelastic properties of SBS-modified epoxy recycled asphalt

ABSTRACT The application of recycled asphalt materials in pavement engineering has been significantly hindered by excessive stiffness and susceptibility to cracking. SBS-modified epoxy asphalt has demonstrated a remarkable ability to enhance material toughness. This study aims to investigate the influence of varying aged asphalt content and epoxy resin content on the low-temperature performance of SBS-modified asphalt. Through the tensile test and bending beam rheometer (BBR) analysis, the low-temperature cracking resistance was evaluated. The viscoelastic constitutive relation was established based on the Burgers model. The results indicate that increasing epoxy content enhances material strength, reduces elongation at break and improves anti-crack performance. The toughening effect of epoxy enhances the asphalt's resistance to deformation and stress relaxation. Differential scanning calorimetry (DSC) was employed to study the curing behaviour, and nonisothermal curing kinetic equations were established. Frequency sweep tests were conducted to construct complex modulus and phase angle master curves, revealing that the maximum complex modulus and optimal low-temperature performance were achieved at 40% epoxy content. The glass transition temperatures of all materials were below 15°C, confirming their superior toughness at ambient temperatures. It lays the foundation for optimising the material design and facilitating the widespread application of epoxy-modified recycled asphalt.