Modification of bitumen by EPDM blended with hybrid nanoparticles: Physical, thermal, and rheological properties

The aim of this research is to study the physical, thermal, and rheological properties of bitumen modified with ethylene propylene diene monomer (EPDM) elastomer and hybrid nanoparticles including carbon nanotubes (CNTs) masterbatch and bentonite nanoclay. Modified bitumen samples were prepared by mixing 60/70 bitumen with 3% EPDM, 0.1% CNT masterbatch, and 1.5% and 4.5% bentonite nanoclay. It was found that addition of these nanoparticles increased the softening point, reduced the penetration degree as well as temperature susceptibility of the modified bitumens. Results of rheological studies in the linear viscoelastic range showed that for the hybrid samples reinforced with EPDM, CNT masterbatch, and nanoclay, complex shear modulus was increased at high temperatures and the rutting factor was shifted from 81 degrees C for the unmodified bitumen to >90 degrees C for the EPDM-nano-modified bitumens. Thermogravimetric analysis also showed the improvement in the thermal degradation behavior of the hybrid samples. Our results indicate that the addition of small amounts of the additives used in this work can highly enhance the viscoelastic behavior of the bitumen at elevated temperatures. According to the findings of this work, the addition of EPDM (3%) and hybrid nanoparticles of CNT masterbatch (0.1%) and bentonite nanoclay (1.5%) to bitumen can synergistically result in the lowest penetration degree, highest softening point, and lowest temperature susceptibility and has the potential to have a better performance in warm areas.