Experimental study on aging properties and modification mechanism of Trinidad lake asphalt modified bitumen

• TLA can effectively ameliorate aging resistance of thermal-oxidative and UV-aging.
• TLA modification on asphalt was mainly physical modification.
• TLA can improve the intersection effect between asphaltene and other components in bitumen.
• Asphalt with TLA was a more stable system than without modifier.

Trinidad lake asphalt (TLA) modified bitumen was prepared to study effect on aging properties and study modification mechanism. The aged blend was prepared by thin film oven test (TFOT), pressure aging vessel (PAV) and ultraviolet (UV) radiation, respectively. Morphology characteristics of modified bitumen were investigated by infrared spectra (IR) and atomic force microscope (AFM). The retained penetration (RP) can be increased while viscosity aged index (VAI) and softening point increment (ΔS) get decreased after aging simulation. It indicated the addition of TLA can effectively ameliorate aging resistance of thermal-oxidative and UV-aging. The susceptible degree of softening point ratio was higher than ΔS but lower than RP. From IR spectra, there are no new absorption peaks added for TLA addition and the modification was mainly physical. Investigation of AFM showed that addition of TLA change the intersection effect between asphaltene and other bitumen components to form the more stable system. Besides, the association effect of the dispersed phase improved system rigidity, softening point and viscosity.