Multiscale study on aging process and mechanism of high viscosity Asphalt: Macro-micro experiments and quantum chemical molecular simulation

•The experiments were combined with the quantum chemical simulation, so as to study the performance changes and reaction mechanisms of HVA during aging.•The macro experiments including penetration, softening point, ductility, viscosity, dynamic shear rheological (DSR) and bending beam rheological (BBR) tests were conducted, so as to clarify the macro property and performance changes.•The micro tests including Fourier transform infrared spectroscopy (FTIR), fluorescence microscope (FM), scanning electron microscopy (SEM) and gel permeation chromatography (GPC) tests were carried out, so as to obtain the changes of macro properties, functional groups, molecular weight and microstructure.•Quantum chemical molecular simulation was conducted to analyze the reaction sites, steps and products of styrene–butadienestyrene (SBS) and asphalt components in HVA under the coupling effect of oxygen, water and ultraviolet.