Effects of Polyphosphoric Acid on Physical, Rheological, and Chemical Properties of Styrene-Butadiene-Styrene (SBS)-Modified Asphalt Binder

Albayati, Amjad H; Al-Kheetan, Mazen J; Al-Ani, Aliaa F; Wang, Yu; Mohammed, Ahmed M; Moudhafar, Mustafa M

Abstract

High temperatures combined with heavy traffic load necessitate asphalt binder modification to enhance its performance and durability. This research examines the effects of polyphosphoric acid (PPA) on the physical, rheological, and chemical properties of styrene-butadiene-styrene (SBS)-modified asphalt binders. Asphalt binders were prepared by adding 3% SBS and varying PPA dosages of 0.3%, 0.6%, and 0.9% by weight of asphalt cement. The experiment investigated the physical properties (penetration, softening point, ductility, viscosity, and specific gravity), the rheological properties (the performance grading (PG), multi-stress creep recovery (MSCR), and linear amplitude sweep (LAS)), and the microstructure and chemical composition of the modified asphalt binder. The results demonstrated impressive improvements in rutting resistance and stiffness. Adding 3% SBS and 0.9% PPA increased the rutting factor (G*/sin δ) by 165% and the high-temperature PG from 74.2 °C to 93.6 °C compared to the virgin asphalt binder. However, the optimum fatigue resistance was obtained by adding 0.3% PPA to the SBS asphalt binder. The microstructure and composition analysis revealed that using SBS and PPA together enhanced binder homogeneity and reduced voids. Lastly, an Overall Desirability (OD) analysis suggested the 3% SBS and 0.3% PPA to be the most effectively balanced formulation for the demand of high temperature and heavy traffic conditions. However, further field studies are recommended to validate the results under real-world conditions.

• Journal Article Type: Article
• Acceptance Date: Feb 6, 2025
• Online Publication Date: Feb 9, 2025
• Publication Date: Feb 9, 2025
• Deposit Date: Feb 10, 2025
• Publicly Available Date: Feb 10, 2025
• Journal: Journal of Composites Science
• Electronic ISSN: 2504-477X
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Issue: 2
• Pages: 78
• DOI: https://doi.org/10.3390/jcs9020078
• Keywords: polyphosphoric acid (PPA); SBS-modified asphalt; rheological properties; MSCR; LAS