Stabilisation mechanism of emulsified rubberised asphalt revealed by coarse-grained molecular dynamics

To address the limitations of the long-standing reliance on inefficient trial-and-error testing in the formulation of emulsified asphalt, this study combined coarse-grained molecular dynamics (CGMD) simulations with macroscopic experiments to investigate the formation stability of emulsified rubberised asphalt (ERA) and evaluate the reliability of CGMD for preliminary formulation screening. The results show that the addition of waste tire rubber reduces the stability of emulsified asphalt systems prepared with either cationic emulsifier cetyltrimethylammonium bromide (CTAB) or anionic emulsifier sodium dodecyl sulfonate (SDSN). However, at high rubber content, the SDSN system forms a thicker interfacial adsorption film with lower interfacial formation energy, demonstrating better stability than the CTAB system. The emulsifier content has a critical value of 5%; exceeding this threshold effectively stabilises the interfacial tension. Among asphalt components, resin and aromatics help reduce interfacial tension, whereas asphaltenes increase the difficulty of emulsion formation.