Modified Asphalt with Styrene Butadiene Styrene and Polyethylene Glycol: Assessment of Water Susceptibility and Rutting Resistance of Asphalt Mixture

Abstract Use of hybrid-polymer binders is important to minimize the failure of asphalt pavements due to temperature variations. So, this research assesses the performance of asphalt mixtures with the modification of styrene-butadiene-styrene (SBS) and polyethylene glycol (PEG) as single and hybrid-polymer binders. The SBS content in the asphalt binder was 2%, 3%, and 4% and the PEG content, 1.5%, 2.5%, and 3.5% by weight of binder. Further, SBS-PEG blend binders were also developed to assess the effect of their combination on the properties of asphalt binder and mixture. Asphalt binder tests were done to measure the change in consistency and tensile strength of the asphalt binder. While, testing of the mixtures' performance was done via splitting test in dry and wet conditions to measure their water resistance, as well as wheel tracking test to measure rutting resistance. It was observed that the mixtures containing 4% SBS and 3.5% PEG (SP3) had the highest softening point and the lowest penetration value, suggesting increased strength and thermal stability. Hybrid modified mixtures demonstrated improved strength and moisture resistance, with SP3 mixture showing the maximum splitting strengths (1588 and 1470 kPa under dry and wet conditions, respectively) and a better strength ratio than the control mixture. The rutting test also showed an improvement in permanent deformation, with rut depths of 1.4–1.44 mm for the modified mixtures compared to 4.49 mm for unmodified mixture. The hybrid polymer method could be a potential solution to increase the life of pavements in areas with high traffic and harsh climatic conditions.