Bonding performance and damage assessment of BFRP- ECC interface

: The interfacial bonding behavior between basalt fiber reinforced polymer (BFRP) grids and engineered cementitious composites (ECC) governs the synergistic stress response of the composite system. Nevertheless, very few studies have been dedicated to investigating the interfacial bonding behavior and damage evaluation of this composite interface. This study investigates, via pull-off tests the effects of ECC protective layer thickness, ECC strength, BFRP grid anchorage length, grid distribution rate, and transverse fiber bundle length on the bond-slip behavior at the BFRP grid and ECC (BFRP-ECC) interface. The interfacial bond failure evolution was analyzed, and a quantitative model for bond-slip characteristic values was established. Results demonstrate that increasing the ECC protective layer thickness, ECC strength and transverse fiber bundle length enhances interfacial bonding performance. Notably, increasing ECC strength provides the most significant improvement (58.8% increase in bond strength). Conversely, higher BFRP grid distribution rates and longer anchorage lengths reduce bonding performance. Finally, formulas for ultimate bond stress, and a damage prediction model were developed using statistical regression analysis. This study offers robust theoretical support for the optimal design of BFRP-ECC composite components.