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The interfacial adhesion between aggregate and asphalt is a critical factor affecting the water damage resistance performance of asphalt mixtures. To enhance the adhesion between aggregate and asphalt, Methyltrimethoxysilane (MPTMS) and Dimethyldimethoxysilane (DMDMOS) were co-opted to modify the aggregate surface. The interfacial strength between aggregate and asphalt was analyzed by water boiling test and contact angle experiment, and the mechanism of aggregate interfacial modification was investigated by combining SEM, FTIR and MD. The results showed that: hydrophobic treatment of aggregates reduces the water absorption rate of aggregates in a wet environment and significantly improves the water damage resistance of asphalt mixtures; MPTMS and DMDMOS reduced the aggregate surface polarity component, thus improving the match between aggregate and asphalt; The optimal processing environment for aggregates is acidity and 30 minutes. Further mechanistic tests and simulations showed that the reactive Si-O portion of the polymer reacts with the Si-O-C portion of MPTMS and DMDMOS to form hydrophobic clusters on the surface of the polymer, increasing the aggregate surface roughness. The clusters attract asphalt molecules to arrange closely and orderly around them. The intramolecular interactions and molecular angular energy of asphalt molecules are significantly reduced, which improves the stability of the aggregate-asphalt system, and further enhances the bonding energy between the aggregate and the asphalt, thus improving the water damage resistance of asphalt mixtures. • MPTMS and DMDMOS can improves the adhesion properties of asphalt mixtures. • An acidic environment and a 30-minute processing time are optimal. • MPTMS and DMDMOS react with aggregates to form Si-O-Si and produce fluffy protrusions. • The fluffy protrusions affects the arrangement of asphalt molecules. [ABSTRACT FROM AUTHOR]

• A matrix binder was modified to possess excellent low-temperature properties and anti-ultraviolet aging properties. • The response surface method was used to determine the dosage of modifies. • The interaction and modification mechanism of modifiers were revealed by FTIR and SEM. In order to improve the high-temperature performance and anti-ultraviolet aging performance of butadiene styrene rubber (SBR) modified asphalt, nano-TiO 2 and Montmorillonite (MMT) were used for composite modification, and the test scheme was determined by Box Behnken Design (BBD). The high-speed shearing method is used to prepare nano-TiO 2 /MMT/SBR composite modified asphalt. Meanwhile, the dynamic shear rheometer (DSR) test and the bending beam rheometer (BBR) test were used to evaluate the rheological properties of the composite modified asphalt before and after aging to evaluate its anti-ultraviolet aging performance. Finally, the interaction and modification mechanism of the modifiers were revealed by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The results show that the optimal dosage of nano-TiO 2 , nano-MMT and SBR latex (solid content 60%) are 1.5%, 4%, and 6%, respectively. The synergistic effect of nano-TiO 2 and nano-MMT can significantly delay the conversion process of light components to asphaltenes during asphalt aging, and makes CMI value of SBR modified asphalt significantly reduced and almost stabilized at about 2, and the average stiffness modulus change rate decreases from 0.27 to 0.13, and the carbonyl index dropped from 5.16 to 0.28. SEM test results show that nano-TiO 2 particles can be used as physical cross-linking points to promote the combination of nano-MMT/SBR modifiers and asphalt, making the microstructure of nano-TiO 2 /MMT/SBR modified asphalt more stable and uniform. The modification of Nano-TiO 2 /MMT/SBR to asphalt is a physical modification process, more Si-O-Si functional groups were generated during the aging process of MMT, which further promote the formation of MMT and asphalt network structure. In conclusion, the study of nano-TiO 2 /MMT/SBR composite modified asphalt in this paper provided a reference for the selection of modified asphalt in cold and ultraviolet regions. [ABSTRACT FROM AUTHOR]

• The improvement of the rheological properties of asphalt by graphene was studied. • Using multiple-scale experiments combined with molecular dynamics simulation. • The focus is on the size effect of graphene on the modification efficiency. The use of waste rubber powder modified asphalt (RA) in road engineering can lead to environmental and economic benefits. However, there are still some concerns over the performance of the pavement with RA, especially the rheological properties under heavy traffic conditions. This paper aims to investigate the improvement effects of graphene on the rheological properties of RA using multiple-scale experimental characterizations combined with molecular dynamics simulation. Special attention was paid to the influence of geometric characteristics of graphene on the modification efficiency. The experimental findings demonstrated that the physical blending of graphene and RA could enhance viscoelasticity, persistent deformation, and mobility resistance of modified asphalt, while its low-temperature performances were marginally improved with the graphene. Graphene with a single layer or a few layers was more efficient in enhancing the high-temperature deformation and rutting resistance and microstructures of RA than that with multiple layers. The molecular dynamics simulation results showed that graphene could improve the shear viscosity of the modified asphalt and inhibit the diffusion of asphalt components, and the effect on the low-temperature performance is related to the size effect. Moreover, the size of graphene particles could strongly influence the performances of the modified asphalt. Specifically, increasing the graphene size decreased the shear viscosity, free volume fraction, and glass transition temperature, indicating the improved deformation resistance. The change in the number of graphene layers was more effective in altering the modification effect of small-sized graphene compared to large-sized graphene. This research can offer a theoretical guideline for optimizing the use of graphene in modified asphalt. [ABSTRACT FROM AUTHOR]