<p>This study aims to investigate the failure modes at the interface of semi-flexible pavement (SFP) materials. The cohesive and wetting properties of asphalt materials, as well as two types of grout (early strength cement grout - ELS and high strength cement grout - CHS), were evaluated through pull-out tests and contact angle experiments. The rheological properties of the grout/asphalt mortar were assessed using dynamic shear rheometer (DSR) testing. The interaction coefficient, complex shear modulus, and complex viscosity coefficients of the grout/asphalt mortar were calculated to analyze the interaction between the grout and asphalt. Failure modes were identified through image analysis of semi-circular bending test (SCB) specimens. Results indicate that ELS specimens exhibit a lower grout/asphalt interface failure ratio compared to CHS specimens, due to the superior wettability and interaction of ELS grout. As the temperature increases, the proportions of cement fracture and aggregate failure decrease, while the proportion of asphalt cohesive failure surfaces increases. Furthermore, the bonding strength of SBS-modified asphalt with the grout exceeds that of pure asphalt.</p>