Enhanced waterproofing and adhesion of emulsified asphalt via WER/WPU composite multi-component modification

Modified emulsified asphalt is widely applied as a waterproof adhesive layer for bridge decks. However, the increasing prevalence of deck distress indicates that conventional formulations cannot satisfy the stringent durability requirements under complex service conditions. To overcome these limitations, a polymer-composite multi-component modified emulsified asphalt (PCMEA) binder with superior waterproofing and adhesion was developed. The modification mechanism was investigated using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), fluorescence microscopy (FM), and Fourier transform infrared spectroscopy (FTIR), while hydrophobic characteristics were analyzed via 3D confocal imaging, SEM, and contact angle measurements. Results indicate that waterborne epoxy resin (WER) and waterborne polyurethane (WPU) form an interpenetrating polymer network through hydrogen bonding and molecular diffusion, integrating epoxy rigidity with polyurethane flexibility. The synergistic effects of poly(trifluoropropylmethylsiloxane) (PF), silica (SiO₂), and glass fiber (GF) further enhance surface energy regulation, mechanical strength, and toughness. PCMEA exhibits significantly improved hydrophobicity, with no water penetration under 0.3 MPa pressure. Mechanical tests confirm its high bonding strength, thermal stability, frost resistance, and corrosion resistance. This study elucidates the modification mechanism of polymer-composite emulsified asphalt and provides a feasible strategy for developing high-performance waterproof adhesive materials, offering valuable implications for extending bridge deck durability and mitigating pavement distresses.