Effects and mechanism of oil-absorbing organogel as a novel modifier on the performance of bitumen mixture

The unstable thermochemical properties of conventional polymer bitumen modifiers lead to a gradual invalid of effects on the bitumen performance in real service environments. As a novel modifier, the oil-absorbing organogel has been shown to enhance the properties of bitumen due to its superior stability and ability to absorb bitumen components. However, its effects and mechanisms on the performance of bitumen mixtures remain unclear. In this study, the oil-absorbing organogel polystyrene-stearyl methacrylate (P(S-SMAL)) was synthesized and used to prepare modified bitumens and mixtures. Rheological tests on bitumen and mechanical tests on the bitumen mixture indicated that P(S-SMAL) could enhance the high-temperature properties of bitumen and the mechanical properties of the bitumen mixture, while maintaining the low-temperature performance of both. With 5 % P(S-SMAL) added, the modified bitumen deformation resistance improved by 22.25 %, permanent deformation reduced by 47.65 %, and the anti-rutting properties of the modified bitumen mixture improved by 111.22 %. The enhanced performance of the bitumen mixture is attributed to the improved properties of P(S-SMAL) modified bitumen, resulting from the "supporting" and "hardening" effects of P(S-SMAL), as well as the hydrophobic nature of the modified bitumen film within the aggregates, driven by the lipophilic characteristics of P(S-SMAL). • Organogel polystyrene-stearyl methacrylate (P(S-SMAL)) was applied to produce modified bitumen and mixtures. • P(S-SMAL) modified bitumen exhibited improved high-temperature properties, particularly with higher addition content. • Increasing the content of P(S-SMAL) can gradually enhance the mechnical and anti-rutting properties of the bitumen mixture. • Enhanced performance of P(S-SMAL) modified bitumen results in improved properties of the bitumen mixture.