Intermediate- and high-temperature damage of bitumen modified by HDPE from various sources

This research investigated the effect of high-density polyethylene (HDPE) from various sources on the damage-related behaviour of bitumen in the intermediate- and high-temperature domains. For this purpose, base bitumen was modified by the mass fraction of 1.5% of HDPE from post-industrial recycled pellets and from post-consumer recycled flakes. The experimental programme consisted of the multiple stress creep and recovery from 40 to 70 degrees C and of the linear shear strain amplitude sweep at 10, 20, and 30 degrees C. The HDPE significantly reduced the non-recoverable creep compliance but increased the elastic recovery. The post-industrial HDPE-modified bitumen exhibited superior resistance to permanent deformation, with its crystallinity recognised as the most important factor. This reduced the susceptibility of its behaviour to shear stress and temperature. The HDPE-modified bitumen had a considerably longer fatigue life, but its sensitivity to premature failure at low temperatures and the conspicuously high brittleness represented the main issue for further improvements.