Abstract

This study examined the effects of adding polyethylene glycol (PEG) on the conventional properties and temperature susceptibility of Iraqi asphalt binder. The asphalt binder, a 40/50 penetration grade obtained from a local site, was modified by adding PEG at various amounts (1, 3, 5, and 7 wt%) through mechanical blending at a controlled temperature. Conventional binder characterization (penetration, softening point, and ductility) was carried out to compare the properties of the neat and modified bitumens, as the penetration index (PI) was calculated to assess the temperature susceptibility. It was found that as the amount of PEG in the blend increased, the softening point decreased from 54 to 45 C gradually, the penetration increased from 60 to 78 (0.1 mm), while the ductility decreased from 150 to 103 cm, which is an indication that the deformation characteristics of the soft-head asphalt binder were altered by PEG addition. The penetration index also decreased from +0.20 to −1.51, implying that temperature susceptibility increased as the PEG level increased. The most balanced conventional properties were found in the modified binder with 3 wt, ductility of 132 cm and PI of −0.42. Based on the results discussed in this paper, moderate PEG addition may be a promising option for altering the consistency and flexibility of Iraqi asphalt binder, but high PEG content may adversely affect resistance to temperature variations. Further rheological and aging studies are needed to verify its practical suitability for pavement applications.