Physicochemical compatibility assessment of bio-additives and bitumen using solubility science-based approaches

Hu, Yongping; Sreeram, Anand; Al-Tabbaa, Abir; Airey, Gordon D.

Abstract

Increasing environmental concerns necessitate the urgent investigation of alternative, sustainable resources as replacement for fossil fuel-derived bitumen; the primary material used for road construction. One of the promising approaches is the use of bio-based alternatives as partial or full bitumen substitutes in asphalt mixtures. Currently, the selection of bio-additives is subjective, resulting in significant variations in the quality of bio-based bitumen produced and its resulting utility as an engineering material. This study utilised solubility-based measurements using the Hansen solubility parameters (HSP) to assess the fundamental physicochemical compatibility between bitumen and two bio-based additives. Firstly, tall oil (bio-additive-1) and waste cooking oil (bio-additive-2) were employed as bio-sourced additives and bitumen was separated into its basic polarity-based building blocks i.e. maltenes and asphaltenes. Afterwards, the HSPs of bitumen, its subfractions and bio-additives were measured. Frequency sweep tests, linear amplitude sweep (LAS) tests and bending beam rheometer (BBR) tests were carried out to assess the rheological properties of blended bio-bitumen and its relation to solubility-based indices. Bio-additive-1 showed better performance and efficiency compared to bio-additive-2 in improving the low-temperature performance, fatigue life and durability of bio-bitumen. The HSP of bio-additive-1 was closer to those of bitumen and its subfractions compared to bio-additive-2, which likely contributes to increased compatibility. The overlapping ratios of Hansen spheres and bitumen subfractions were positively correlated with the rheological properties of the bio-bitumen. Overall, the findings represent a first step towards development of a robust framework for the scientific design of bio-bitumen in future paving applications.

Citation

Hu, Y., Sreeram, A., Al-Tabbaa, A., & Airey, G. D. (2025). Physicochemical compatibility assessment of bio-additives and bitumen using solubility science-based approaches. Fuel, 387, Article 134361. https://doi.org/10.1016/j.fuel.2025.134361

• Journal Article Type: Article
• Acceptance Date: Jan 7, 2025
• Online Publication Date: Jan 11, 2025
• Publication Date: May 1, 2025
• Deposit Date: Jan 11, 2025
• Publicly Available Date: Jan 15, 2025
• Journal: Fuel
• Print ISSN: 0016-2361
• Electronic ISSN: 1873-7153
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 387
• Article Number: 134361
• DOI: https://doi.org/10.1016/j.fuel.2025.134361
• Keywords: Asphalt, Bio-bitumen, Bio-binder, Hansen Solubility Parameter (HSP), Compatibility
• Public URL: https://nottingham-repository.worktribe.com/output/44078024
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0016236125000857?via%3Dihub