Microstructure and rheological response of laboratory-aged SBS-modified bitumens

Cuciniello, Giacomo; Leandri, Pietro; Filippi, Sara; Lo Presti, Davide; Polacco, Giovanni; Losa, Massimo; Airey, Gordon

Abstract

Polymer additives are widely used to improve the performance of road bitumens including their resistance to hardening during oxidation, although their oxidative inhibitor effect has not been well documented. This study aims to investigate the effect of laboratory-simulated ageing on the microstructure, and rheological properties of Polymer Modified Bitumens (PMBs) prepared with a Styrene-Butadiene-Styrene (SBS) copolymer and sulphur as a cross-linker. The laboratory ageing was conducted through the Rolling Thin Film Oven (RTFO) and the Pressure Aging Vessel (PAV) procedures. The unaged and aged binders were characterised using the Multiple Stress Creep and Recovery (MSCR) test, Gel Permeation Chromatography (GPC) and fluorescence microscopy. The MSCR test showed that the cross-linked polymer had a higher capability of mitigating the effect of bitumen hardening on the rheological response, while for the PMBs without cross-linking, the polymer effects decreased significantly after RTFOT ageing. The GPC results showed that the aromatics, resins and asphaltenes fractions of the unmodified bitumens shifted towards heavier molecules after one cycle of PAV ageing but showed limited variation with further ageing. Similar behaviour was observed for the uncross-linked polymer binders, while for the cross-linked polymer binder, the behaviour depended on the polymer concentration.

Citation

Cuciniello, G., Leandri, P., Filippi, S., Lo Presti, D., Polacco, G., Losa, M., & Airey, G. (2019). Microstructure and rheological response of laboratory-aged SBS-modified bitumens. Road Materials and Pavement Design, https://doi.org/10.1080/14680629.2019.1621771

• Journal Article Type: Article
• Acceptance Date: May 13, 2019
• Online Publication Date: May 27, 2019
• Publication Date: May 27, 2019
• Deposit Date: May 28, 2019
• Publicly Available Date: May 28, 2020
• Journal: Road Materials and Pavement Design
• Print ISSN: 1468-0629
• Electronic ISSN: 2164-7402
• Publisher: Taylor and Francis
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1080/14680629.2019.1621771
• Keywords: Polymer-modified bitumen; SBS; Ageing; GPC; Percent recovery; Sulphur; MSCR
• Public URL: https://nottingham-repository.worktribe.com/output/2101494
• Publisher URL: https://www.tandfonline.com/doi/full/10.1080/14680629.2019.1621771
• Additional Information: This is an Accepted Manuscript of an article published by Taylor & Francis in Road Materials and Pavement Design on 27.05.2019, available online: http://www.tandfonline.com/10.1080/14680629.2019.1621771
• Contract Date: May 30, 2019