Study on the Properties and Mechanism of Recycled Aggregate/Asphalt Interface Modified by Silane Coupling Agent

The use of recycled concrete aggregates (RCA) instead natural in hot-mix asphalt mixtures is one the ways to achieve energy savings and reduce carbon emissions road engineering. However, cement mortar on surface RCA adversely affects adhesion properties between aggregates, leading a reduction performance characteristics mixtures. In this study, silane coupling agent (SCA) was employed improve RCA/asphalt interface. enhancement mechanism SCA interface investigated from multiple perspectives, including macroscopic properties, interfacial microstructure, nanoscale interactions. Firstly, behavior tensile strength were determined through boiling water test direct test, both before after modification. Secondly, scanning electron microscopy (SEM) observe microstructure Finally, main component mortar, calcium silicate hydrate (C-S-H), taken as research subject investigation examine hydrogen bonding, interaction energy, transition zone C-S-H/asphalt system using molecular dynamics methodology. results demonstrate two-level at scale following increased by 72.2% 119.7% under dry wet conditions, respectively. At microscopic scale, it observed that pores repaired modification, resulting more tightly bonded asphalt. nanoscale, modification reduces hydrophilicity C-S-H surface, increases resistance interface, enhances weak This study provides theoretical basis for enhance bond lays foundation application highways.