Enhancing bond performance of near surface mounted CFRP in high-strength strain-hardening cementitious composites (SHCC) through surface treatment

Strain-hardening cementitious composites (SHCC) and near surface mounted (NSM) carbon fiber reinforced polymer (CFRP) systems are pivotal for enhancing the durability and load-bearing capacity of reinforced concrete structures. However, the interaction between NSM-CFRP laminate strips and high-strength SHCC remains less understood, while the efficacy of available surface treatment method for CFRP-concrete bond remains unvalidated in high-strength SHCC systems. To fill this research gap, we explored their bond by examining the effects of CFRP strip configurations and surface treatments (with silica sands in various mesh sizes). Experimental findings indicated that fine sand particles (mesh 80–120) substantially improved the bond strength. Notably, configurations with CFRP strips oriented in the load direction and those with increased layering demonstrate enhanced load-bearing capacities and stress distribution. A comprehensive 3D finite element model (FEM) was developed and validated against experimental results to simulate the bond characteristics under varying conditions. The FEM successfully predicted improvements in bond performance with changes in surface texture and CFRP configuration, aligning closely with experimental data on bond strength enhancements. These findings elucidate the significant impact of material configuration on the performance of NSM-CFRP systems in SHCC, providing a robust foundation for design and application of these composites in structural reinforcement. • Sand coating with 80–120 mesh silica significantly improved CFRP–SHCC bond strength. • NSM-CFRP strips in high-strength SHCC achieved a peak bond stress of 4.35 MPa. • Strip orientation (90°) enhanced bond efficiency compared to 0° placement. • Increasing CFRP layers shifted the failure mode from rupture to interfacial debonding. • A validated 3D FEM accurately predicted load–slip behavior for NSM-CFRP systems.