Interface bonding performance between engineered cementitious composites (ECC)/hybrid fibre ECCs and masonry after high-temperature exposure

The use of a hybrid fibre engineered cementitious composite (HECC) as a replacement for ordinary mortar (OM) in masonry reinforcement was investigated. The HECC, which included polyvinyl alcohol fibre (PVAF) and steel fibre (SF), was found to improve both bonding performance and fire resistance. Bonding properties were assessed through tensile and shear bond strength tests after exposure to various temperatures. The results showed that, after exposure to temperatures up to 600°C, the HECC outperformed the OM and the engineered cementitious composite (ECC) made with only PVAF in terms of both tensile and shear strength. After 600°C exposure, the HECC exhibited tensile and shear strengths of 0.59 MPa and 0.78 MPa, respectively, significantly higher than the tensile strengths of the OM (0.22 MPa) and the ECC (0.49 MPa). The energy consumption of the HECC was also higher, suggesting enhanced mechanical energy absorption. Scanning electron microscopy analysis revealed that the incorporation of SF improved the microstructure and high-temperature bonding behaviour. Overall, these findings indicate that HECC is a highly effective alternative to conventional mortar, offering improved durability, bonding strength and fire resistance for masonry structures.