Comparing the performance of SBS and thermoplastics modified asphalt binders and asphalt mixes

Abstract

This study comprehensively compares the conventional, rheological, morphological, and asphalt mix performance among SBS and several thermoplastics (TPs) modified binders. TPs modified binders (TP-MBs) may have modulus values similar to SBS modified binders (SBS-MBs), but several other critical properties were far inferior. Percent elastic recovery of ungrafted TP-MBs was < 10 percent, phase angle values were close to 80°, and the softening point was 15–20°C lesser than SBS-MBs. At intermediate and low temperatures, TP-MBs exhibited higher complex modulus values and increased the PG intermediate and low temperature. The presence of TP polymer even reduces the ductility compared to the base binder. Similarly, TP-MBs enhance the Marshall stability and rut resistance in mixes by 20–40 percent, but the improvement was not observed in moisture susceptibility, indirect tensile strength, and fatigue crack performance. Hence, analysis limited to the modulus of the MBs, Marshall stability, and rutting in mixes can falsely indicate that TPs can increase the overall performance of asphalt binders and mixes.